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Sample records for wind vectors liu

  1. Liu Xiaopan

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science. Liu Xiaopan. Articles written in Bulletin of Materials Science. Volume 32 Issue 5 October 2009 pp 549-554 Composites. High-temperature oxidation behaviour of Ti3Si(1–)AlC2 in air · Liu Xiaopan Wan Long Bu Zhongheng Nie Daojun · More Details Abstract Fulltext PDF.

  2. Hurricane Wind Vector Estimates from WindSat Polarimetric Radiometer

    National Research Council Canada - National Science Library

    Adams, Ian S; Hennon, Christopther C; Jones, W. L; Ahmad, Khalil

    2005-01-01

    .... In late 2004, the first preliminary oceanic wind vector results were released, and this paper presents the first evaluation of this product for several Atlantic hurricanes during the 2003 season...

  3. H B Liu

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana. H B Liu. Articles written in Sadhana. Volume 34 Issue 4 August 2009 pp 599-606. Of light, of MEMS: Optical MEMS in telecommunications and beyond · F Chollet H B Liu M Ashraf B Thubthimthong X M Zhang G Hegde A Asundi V M Murukeshan A Q Liu · More Details Abstract Fulltext PDF.

  4. WAN-MING LIU

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana. WAN-MING LIU. Articles written in Sadhana. Volume 41 Issue 7 July 2016 pp 713-719. Integrated fleet assignment and aircraft routing based on delay propagation · WAN-MING LIU XING-HUI ZHU YAN-LONG QI · More Details Abstract Fulltext PDF. Airlines' expensive resources, especially aircraft ...

  5. LIU 2011 event

    CERN Multimedia

    BE Department

    2011-01-01

    The LHC injectors upgrade (LIU) project was launched at the end of 2010 to coordinate the preparation of the CERN accelerator complex to meet the needs of the High Luminosity LHC (HL-LHC) until at least 2030. It should be completed by the end of the second long LHC shutdown, presently scheduled for 2018.   The goal of the LIU-2011 event is to present the status and plans of the LIU project, describing the needs and the actions foreseen in the different accelerators, from Linac4 to the PSB, PS and SPS.  

  6. Day-Ahead Wind Speed Forecasting Using Relevance Vector Machine

    Directory of Open Access Journals (Sweden)

    Guoqiang Sun

    2014-01-01

    Full Text Available With the development of wind power technology, the security of the power system, power quality, and stable operation will meet new challenges. So, in this paper, we propose a recently developed machine learning technique, relevance vector machine (RVM, for day-ahead wind speed forecasting. We combine Gaussian kernel function and polynomial kernel function to get mixed kernel for RVM. Then, RVM is compared with back propagation neural network (BP and support vector machine (SVM for wind speed forecasting in four seasons in precision and velocity; the forecast results demonstrate that the proposed method is reasonable and effective.

  7. Impact of Scatterometer Ocean Wind Vector Data on NOAA Operations

    Science.gov (United States)

    Jelenak, Z.; Chang, P.; Brennan, M. J.; Sienkiewicz, J. M.

    2015-12-01

    Near real-time measurements of ocean surface vector winds (OSVW), including both wind speed and direction from non-NOAA satellites, are being widely used in critical operational NOAA forecasting and warning activities. The scatterometer wind data data have had major operational impact in: a) determining wind warning areas for mid-latitude systems (gale, storm,hurricane force); b) determining tropical cyclone 34-knot and 50-knot wind radii. c) tracking the center location of tropical cyclones, including the initial identification of their formation. d) identifying and warning of extreme gap and jet wind events at all latitudes. e) identifying the current location of frontal systems and high and low pressure centers. f) improving coastal surf and swell forecasts Much has been learned about the importance and utility of satellite OSVW data in operational weather forecasting and warning by exploiting OSVW research satellites in near real-time. Since December 1999 when first data from QuikSCAT scatterometer became available in near real time NOAA operations have been benefiting from ASCAT scatterometer observations on MetOp-A and B, Indian OSCAT scatterometer on OceanSat-3 and lately NASA's RapidScat mission on International Space Station. With oceans comprising over 70 percent of the earth's surface, the impacts of these data have been tremendous in serving society's needs for weather and water information and in supporting the nation's commerce with information for safe, efficient, and environmentally sound transportation and coastal preparedness. The satellite OSVW experience that has been gained over the past decade by users in the operational weather community allows for realistic operational OSVW requirements to be properly stated for future missions. Successful model of transitioning research data into operation implemented by Ocean Winds Team in NOAA's NESDIS/STAR office and subsequent data impacts will be presented and discussed.

  8. Blended 6-Hourly Sea Surface Wind Vectors and Wind Stress on a Global 0.25 Degree Grid (1987-2011)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Blended Global Sea Surface Winds products contain ocean surface wind vectors and wind stress on a global 0.25 degree grid, in multiple time resolutions of...

  9. A Novel Empirical Mode Decomposition With Support Vector Regression for Wind Speed Forecasting.

    Science.gov (United States)

    Ren, Ye; Suganthan, Ponnuthurai Nagaratnam; Srikanth, Narasimalu

    2016-08-01

    Wind energy is a clean and an abundant renewable energy source. Accurate wind speed forecasting is essential for power dispatch planning, unit commitment decision, maintenance scheduling, and regulation. However, wind is intermittent and wind speed is difficult to predict. This brief proposes a novel wind speed forecasting method by integrating empirical mode decomposition (EMD) and support vector regression (SVR) methods. The EMD is used to decompose the wind speed time series into several intrinsic mode functions (IMFs) and a residue. Subsequently, a vector combining one historical data from each IMF and the residue is generated to train the SVR. The proposed EMD-SVR model is evaluated with a wind speed data set. The proposed EMD-SVR model outperforms several recently reported methods with respect to accuracy or computational complexity.

  10. Poynting Vector in High-Temperature Superconducting Transformers with a Separate Excitation Winding

    Science.gov (United States)

    Volkov, E. P.; Dzhafarov, E. A.

    2017-12-01

    The HTSC transformer with a separate winding for excitation of the mutual magnetic flux is considered; the windings of the transformer are performed of first- or second-generation HTSC wires. The article presents the design and the electrical circuit of the transformer, the equations of electromagnetic balance, and the total resistance of the primary and secondary power windings and the separate excitation winding. The transfer of the electromagnetic field energy is considered in a single-phase HTSC transformer with the separate excitation winding using the Poynting vector. The temporal change in the reactive and active components of the Poynting vector and the decrease in the leakage energy flux of the separate excitation winding are shown, which causes an increase in the critical current density of the HTSC power windings, a decrease in the energy losses in the latter, and an increase the in the specific power of the HTSC transformer.

  11. Auto-correlation analysis of ocean surface wind vectors

    Indian Academy of Sciences (India)

    The nature of the inherent temporal variability of surface winds is analyzed by comparison of winds obtained through different measurement methods. In this work, an auto-correlation analysis of a time series data of surface winds measured in situ by a deep water buoy in the Indian Ocean has been carried out. Hourly time ...

  12. Estimation of the wind turbine yaw error by support vector machines

    DEFF Research Database (Denmark)

    Sheibat-Othman, Nida; Othman, Sami; Tayari, Raoaa

    2015-01-01

    Wind turbine yaw error information is of high importance in controlling wind turbine power and structural load. Normally used wind vanes are imprecise. In this work, the estimation of yaw error in wind turbines is studied using support vector machines for regression (SVR). As the methodology...... is data-based, simulated data from a high fidelity aero-elastic model is used for learning. The model simulates a variable speed horizontal-axis wind turbine composed of three blades and a full converter. Both partial load (blade angles fixed at 0 deg) and full load zones (active pitch actuators...

  13. Auto-correlation analysis of ocean surface wind vectors

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    satellite and in situ measurements. A case study using the TRMM Microwave Imager (TMI) and. Indian Ocean buoy wind speed data resulted in an improvement of about 10%. 1. Introduction. The need for studying temporal variability of oceanic winds has been pointed out by many authors (for example, Ezraty R S 1989).

  14. High stability vector-based direct power control for DFIG-based wind turbine

    DEFF Research Database (Denmark)

    Zhu, Rongwu; Chen, Zhe; Wu, Xiaojie

    2015-01-01

    This paper proposes an improved vector-based direct power control (DPC) strategy for the doubly-fed induction generator (DFIG)-based wind energy conversion system. Based on the small signal model, the proposed DPC improves the stability of the DFIG, and avoids the DFIG operating in the marginal...... stable region (the real part of eigenvalue is equal to zero). The vector-based DPC combines with a space vector modulation technique to achieve a constant switching frequency. The simulation and experimental results clearly validate the effectiveness and feasibility of the proposed vector-based DPC...

  15. Plants and ventifacts delineate late Holocene wind vectors in the Coachella Valley, USA

    Science.gov (United States)

    Griffiths, P.G.; Webb, R.H.; Fisher, M.; Muth, Allan

    2009-01-01

    Strong westerly winds that emanate from San Gorgonio Pass, the lowest point between Palm Springs and Los Angeles, California, dominate aeolian transport in the Coachella Valley of the western Sonoran Desert. These winds deposit sand in coppice dunes that are critical habitat for several species, including the state and federally listed threatened species Uma inornata, a lizard. Although wind directions are generally defined in this valley, the wind field has complex interactions with local topography and becomes more variable with distance from the pass. Local, dominant wind directions are preserved by growth patterns of Larrea tridentata (creosote bush), a shrub characteristic of the hot North American deserts, and ventifacts. Exceptionally long-lived, Larrea has the potential to preserve wind direction over centuries to millennia, shaped by the abrasive pruning of windward branches and the persistent training of leeward branches. Wind direction preserved in Larrea individuals and clones was mapped at 192 locations. Compared with wind data from three weather stations, Larrea vectors effectively reflect annual prevailing winds. Ventifacts measured at 24 locations record winds 10° more westerly than Larrea and appear to reflect the direction of the most erosive winds. Based on detailed mapping of local wind directions as preserved in Larrea, only the northern half of the Mission-Morongo Creek floodplain is likely to supply sand to protected U. inornata habitat in the Willow Hole ecological reserve.

  16. Plants and ventifacts delineate late Holocene wind vectors in the Coachella Valley, USA

    Science.gov (United States)

    Griffiths, Peter G.; Webb, Robert H.; Fisher, Mark; Muth, Allan

    Strong westerly winds that emanate from San Gorgonio Pass, the lowest point between Palm Springs and Los Angeles, California, dominate aeolian transport in the Coachella Valley of the western Sonoran Desert. These winds deposit sand in coppice dunes that are critical habitat for several species, including the state and federally listed threatened species Uma inornata, a lizard. Although wind directions are generally defined in this valley, the wind field has complex interactions with local topography and becomes more variable with distance from the pass. Local, dominant wind directions are preserved by growth patterns of Larrea tridentata (creosote bush), a shrub characteristic of the hot North American deserts, and ventifacts. Exceptionally long-lived, Larrea has the potential to preserve wind direction over centuries to millennia, shaped by the abrasive pruning of windward branches and the persistent training of leeward branches. Wind direction preserved in Larrea individuals and clones was mapped at 192 locations. Compared with wind data from three weather stations, Larrea vectors effectively reflect annual prevailing winds. Ventifacts measured at 24 locations record winds 10° more westerly than Larrea and appear to reflect the direction of the most erosive winds. Based on detailed mapping of local wind directions as preserved in Larrea, only the northern half of the Mission-Morongo Creek floodplain is likely to supply sand to protected U. inornata habitat in the Willow Hole ecological reserve.

  17. Auto-correlation analysis of ocean surface wind vectors

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    In this work, an auto-correlation analysis of a time series data of surface winds measured in situ by a deep water buoy in the Indian Ocean has been carried out. Hourly time series data available for 240 hours in the month of May, 1999 were subjected to an auto-correlation analysis. The analysis indicates an exponential fall ...

  18. Very-short-term wind power probabilistic forecasts by sparse vector autoregression

    DEFF Research Database (Denmark)

    Dowell, Jethro; Pinson, Pierre

    2016-01-01

    A spatio-temporal method for producing very-shortterm parametric probabilistic wind power forecasts at a large number of locations is presented. Smart grids containing tens, or hundreds, of wind generators require skilled very-short-term forecasts to operate effectively, and spatial information...... is highly desirable. In addition, probabilistic forecasts are widely regarded as necessary for optimal power system management as they quantify the uncertainty associated with point forecasts. Here we work within a parametric framework based on the logit-normal distribution and forecast its parameters....... The location parameter for multiple wind farms is modelled as a vector-valued spatiotemporal process, and the scale parameter is tracked by modified exponential smoothing. A state-of-the-art technique for fitting sparse vector autoregressive models is employed to model the location parameter and demonstrates...

  19. A Vector Control for Grid-connected Wind Power Generation with Doubly Fed Induction Generator

    Science.gov (United States)

    Kai, Takaaki; Tanaka, Yuji; Kaneda, Hirotoshi; Kobayashi, Daichi; Tanaka, Akio

    Recently, doubly fed induction generator (DFIG) and synchronous generator are mostly applied for wind power generation due to high efficiently for wind energy capture. An inverter system is required to control wind turbine speed and power factor in those generators. The inverter rating of the synchronous generator equals to generator rating. However, DFIG has the advantage that the inverter rating is about 25% to the generator rating. The paper describes a vector control of DFIG inter-connected to power line. The performance of proposed vector control is examined using power system simulation software PSCAD/EMTDC for the DFIG inter-connected to 6.6kv distribution line. The results show good dynamic responses and high accuracy to the stator active power control and the stator reactive power control.

  20. A Statistical Approach to WindSat Ocean Surface Wind Vector Retrieval

    Science.gov (United States)

    2006-01-01

    Crane for assisting in initial development of the regression software. REFERENCES [1] P. W. Gaiser, K. St. Germain, E. M. Twarog , G. A. Poe, W. Purdy...Remote Sens., vol. 40, no. 1, pp. 79–89, Jan. 2002. [12] E. Twarog , P. W. Gaiser, B. Purdy, L. Jones, K. St. Germain, and G. Poe, “WindSat post-launch

  1. Fault diagnosis of direct-drive wind turbine based on support vector machine

    International Nuclear Information System (INIS)

    An, X L; Jiang, D X; Li, S H; Chen, J

    2011-01-01

    A fault diagnosis method of direct-drive wind turbine based on support vector machine (SVM) and feature selection is presented. The time-domain feature parameters of main shaft vibration signal in the horizontal and vertical directions are considered in the method. Firstly, in laboratory scale five experiments of direct-drive wind turbine with normal condition, wind wheel mass imbalance fault, wind wheel aerodynamic imbalance fault, yaw fault and blade airfoil change fault are carried out. The features of five experiments are analyzed. Secondly, the sensitive time-domain feature parameters in the horizontal and vertical directions of vibration signal in the five conditions are selected and used as feature samples. By training, the mapping relation between feature parameters and fault types are established in SVM model. Finally, the performance of the proposed method is verified through experimental data. The results show that the proposed method is effective in identifying the fault of wind turbine. It has good classification ability and robustness to diagnose the fault of direct-drive wind turbine.

  2. Operational Utilization of High Resolution Ocean Surface Wind Vectors (25km or better) in the Marine Forecasting Environment

    National Research Council Canada - National Science Library

    Chang, Paul S; Sienkiewicz, Joseph; Knabb, Richard; Gaiser, Peter W; Long, David G; Freeberg, Mark

    2005-01-01

    .... This work will build upon an ongoing effort to quantify the impacts of QuikSCAT ocean vector wind data in the operational short-term warnings and forecasts issued by the NWS Ocean Prediction Center (OPC...

  3. Operational Utilization of High Resolution Ocean Surface Wind Vectors (25km or Better) in the Marine Forecasting Environment

    National Research Council Canada - National Science Library

    Chang, Paul S; Sienkiewicz, Joseph; Knabb, Richard; Gaiser, Peter W; Long, David G; Freeberg, Mark

    2004-01-01

    .... This work will build upon an ongoing effort to quantify the impacts of QuikSCAT ocean vector wind data in the operational short-term warnings and forecasts issued by the NWS Ocean Prediction Center (OPC...

  4. Fine tuning support vector machines for short-term wind speed forecasting

    International Nuclear Information System (INIS)

    Zhou Junyi; Shi Jing; Li Gong

    2011-01-01

    Research highlights: → A systematic approach to tuning SVM models for wind speed prediction is proposed. → Multiple kernel functions and a wide range of tuning parameters are evaluated, and optimal parameters for each kernel function are obtained. → It is found that the forecasting performance of SVM is closely related to the dynamic characteristics of wind speed. → Under the optimal combination of parameters, different kernels give comparable forecasting accuracy. -- Abstract: Accurate forecasting of wind speed is critical to the effective harvesting of wind energy and the integration of wind power into the existing electric power grid. Least-squares support vector machines (LS-SVM), a powerful technique that is widely applied in a variety of classification and function estimation problems, carries great potential for the application of short-term wind speed forecasting. In this case, tuning the model parameters for optimal forecasting accuracy is a fundamental issue. This paper, for the first time, presents a systematic study on fine tuning of LS-SVM model parameters for one-step ahead wind speed forecasting. Three SVM kernels, namely linear, Gaussian, and polynomial kernels, are implemented. The SVM parameters considered include the training sample size, SVM order, regularization parameter, and kernel parameters. The results show that (1) the performance of LS-SVM is closely related to the dynamic characteristics of wind speed; (2) all parameters investigated greatly affect the performance of LS-SVM models; (3) under the optimal combination of parameters after fine tuning, the three kernels give comparable forecasting accuracy; (4) the performance of linear kernel is worse than the other two kernels when the training sample size or SVM order is small. In addition, LS-SVMs are compared against the persistence approach, and it is found that they can outperform the persistence model in the majority of cases.

  5. The Alignment of the Mean Wind and Stress Vectors in the Unstable Surface Layer

    Science.gov (United States)

    Bernardes, M.; Dias, N. L.

    2010-01-01

    A significant non-alignment between the mean horizontal wind vector and the stress vector was observed for turbulence measurements both above the water surface of a large lake, and over a land surface (soybean crop). Possible causes for this discrepancy such as flow distortion, averaging times and the procedure used for extracting the turbulent fluctuations (low-pass filtering and filter widths etc.), were dismissed after a detailed analysis. Minimum averaging times always less than 30 min were established by calculating ogives, and error bounds for the turbulent stresses were derived with three different approaches, based on integral time scales (first-crossing and lag-window estimates) and on a bootstrap technique. It was found that the mean absolute value of the angle between the mean wind and stress vectors is highly related to atmospheric stability, with the non-alignment increasing distinctively with increasing instability. Given a coordinate rotation that aligns the mean wind with the x direction, this behaviour can be explained by the growth of the relative error of the u- w component with instability. As a result, under more unstable conditions the u- w and the v- w components become of the same order of magnitude, and the local stress vector gives the impression of being non-aligned with the mean wind vector. The relative error of the v- w component is large enough to make it undistinguishable from zero throughout the range of stabilities. Therefore, the standard assumptions of Monin-Obukhov similarity theory hold: it is fair to assume that the v- w stress component is actually zero, and that the non-alignment is a purely statistical effect. An analysis of the dimensionless budgets of the u- w and the v- w components confirms this interpretation, with both shear and buoyant production of u- w decreasing with increasing instability. In the v- w budget, shear production is zero by definition, while buoyancy displays very low-intensity fluctuations around

  6. 78 FR 58519 - Denial of Export Privileges; Sixing Liu

    Science.gov (United States)

    2013-09-24

    ... Powers Act (50 U.S.C. 1701, et seq. (2006 & Supp. IV 2010)). I have received notice of Liu's conviction... DEPARTMENT OF COMMERCE Bureau of Industry and Security Denial of Export Privileges; Sixing Liu In the Matter of: Sixing Liu, a/k/a Steve Liu, Inmate 43102-424, FCI Oxford, Federal Correctional...

  7. Aspects of the determination of winds by means of scatterometry and of the utilization of vector wind data for meteorological forecasts

    Science.gov (United States)

    Pierson, W. J., Jr.; Sylvester, W. B.; Donelan, M. A.

    1986-01-01

    The present paper provides a description of four aspects of scatterometer winds and their uses. The theory of wave generation by the wind is considered along with an analysis of the properties of superobservations, and studies of intermittent versus continuous data assimilation methods for numerical weather predictions which use remotely sensed data. A comparison of the sum of squares versus the maximum likelihood method for recovering the vector winds is also conducted. Questions regarding wind speed, friction velocity, or normal stress are discussed and synoptic scale fields from Seasat-SASS data are examined.

  8. LHC Injectors Upgrade (LIU) Project at CERN

    CERN Document Server

    Shaposhnikova, Elena; Damerau, Heiko; Funken, Anne; Gilardoni, Simone; Goddard, Brennan; Hanke, Klaus; Kobzeva, Lelyzaveta; Lombardi, Alessandra; Manglunki, Django; Mataguez, Simon; Meddahi, Malika; Mikulec, Bettina; Rumolo, Giovanni; Scrivens, Richard; Vretenar, Maurizio

    2016-01-01

    A massive improvement program of the LHC injector chain is presently being conducted under the LIU project. For the proton chain, this includes the replacement of Linac2 with Linac4 as well as all necessary upgrades to the Proton Synchrotron Booster (PSB), the Proton Synchrotron (PS) and Super Proton Synchrotron (SPS), aimed at producing beams with the challenging High Luminosity LHC (HL-LHC) parameters. Regarding the heavy ions, plans to improve the performance of Linac3 and the Low Energy Ion Ring (LEIR) are also pursued under the general LIU program. The full LHC injection chain returned to operation after Long Shutdown 1, with extended beam studies taking place in Run 2. A general project Cost and Schedule Review also took place in March 2015, and several dedicated LIU project reviews were held to address issues awaiting pending decisions. In view of these developments, 2014 and 2015 have been key years to define a number of important aspects of the final LIU path. This paper will describe the reviewed LI...

  9. Recurrence quantification analysis in Liu's attractor

    International Nuclear Information System (INIS)

    Balibrea, Francisco; Caballero, M. Victoria; Molera, Lourdes

    2008-01-01

    Recurrence Quantification Analysis is used to detect transitions chaos to periodical states or chaos to chaos in a new dynamical system proposed by Liu et al. This system contains a control parameter in the second equation and was originally introduced to investigate the forming mechanism of the compound structure of the chaotic attractor which exists when the control parameter is zero

  10. NASA's GMAO Atmospheric Motion Vectors Simulator: Description and Application to the MISTiC Winds Concept

    Science.gov (United States)

    Carvalho, David; McCarty, Will; Errico, Ron; Prive, Nikki

    2018-01-01

    An atmospheric wind vectors (AMVs) simulator was developed by NASA's GMAO to simulate observations from future satellite constellation concepts. The synthetic AMVs can then be used in OSSEs to estimate and quantify the potential added value of new observations to the present Earth observing system and, ultimately, the expected impact on the current weather forecasting skill. The GMAO AMV simulator is a tunable and flexible computer code that is able to simulate AMVs expected to be derived from different instruments and satellite orbit configurations. As a case study and example of the usefulness of this tool, the GMAO AMV simulator was used to simulate AMVs envisioned to be provided by the MISTiC Winds, a NASA mission concept consisting of a constellation of satellites equipped with infrared spectral midwave spectrometers, expected to provide high spatial and temporal resolution temperature and humidity soundings of the troposphere that can be used to derive AMVs from the tracking of clouds and water vapor features. The GMAO AMV simulator identifies trackable clouds and water vapor features in the G5NR and employs a probabilistic function to draw a subset of the identified trackable features. Before the simulator is applied to the MISTiC Winds concept, the simulator was calibrated to yield realistic observations counts and spatial distributions and validated considering as a proxy instrument to the MISTiC Winds the Himawari-8 Advanced Imager (AHI). The simulated AHI AMVs showed a close match with the real AHI AMVs in terms of observation counts and spatial distributions, showing that the GMAO AMVs simulator synthesizes AMVs observations with enough quality and realism to produce a response from the DAS equivalent to the one produced with real observations. When applied to the MISTiC Winds scanning points, it can be expected that the MISTiC Winds will be able to collect approximately 60,000 wind observations every 6 hours, if considering a constellation composed of

  11. Time Series Analysis and Forecasting for Wind Speeds Using Support Vector Regression Coupled with Artificial Intelligent Algorithms

    Directory of Open Access Journals (Sweden)

    Ping Jiang

    2015-01-01

    Full Text Available Wind speed/power has received increasing attention around the earth due to its renewable nature as well as environmental friendliness. With the global installed wind power capacity rapidly increasing, wind industry is growing into a large-scale business. Reliable short-term wind speed forecasts play a practical and crucial role in wind energy conversion systems, such as the dynamic control of wind turbines and power system scheduling. In this paper, an intelligent hybrid model for short-term wind speed prediction is examined; the model is based on cross correlation (CC analysis and a support vector regression (SVR model that is coupled with brainstorm optimization (BSO and cuckoo search (CS algorithms, which are successfully utilized for parameter determination. The proposed hybrid models were used to forecast short-term wind speeds collected from four wind turbines located on a wind farm in China. The forecasting results demonstrate that the intelligent hybrid models outperform single models for short-term wind speed forecasting, which mainly results from the superiority of BSO and CS for parameter optimization.

  12. Vectors

    DEFF Research Database (Denmark)

    Boeriis, Morten; van Leeuwen, Theo

    2017-01-01

    This article revisits the concept of vectors, which, in Kress and van Leeuwen’s Reading Images (2006), plays a crucial role in distinguishing between ‘narrative’, action-oriented processes and ‘conceptual’, state-oriented processes. The use of this concept in image analysis has usually focused...... on the most salient vectors, and this works well, but many images contain a plethora of vectors, which makes their structure quite different from the linguistic transitivity structures with which Kress and van Leeuwen have compared ‘narrative’ images. It can also be asked whether facial expression vectors...... should be taken into account in discussing ‘reactions’, which Kress and van Leeuwen link only to eyeline vectors. Finally, the question can be raised as to whether actions are always realized by vectors. Drawing on a re-reading of Rudolf Arnheim’s account of vectors, these issues are outlined...

  13. Calibration Performance and Capabilities of the New Compact Ocean Wind Vector Radiometer System

    Science.gov (United States)

    Brown, S. T.; Focardi, P.; Kitiyakara, A.; Maiwald, F.; Montes, O.; Padmanabhan, S.; Redick, R.; Russell, D.; Wincentsen, J.

    2014-12-01

    The paper describes performance and capabilities of a new satellite conically imaging microwave radiometer system, the Compact Ocean Wind Vector Radiometer (COWVR), being built by the Jet Propulsion Laboratory (JPL) for an Air Force demonstration mission. COWVR is an 18-34 GHz fully polarimetric radiometer designed to provide measurements of ocean vector winds with an accuracy that meets or exceeds that provided by WindSat, but using a simpler design which has both calibration and cost advantages. Heritage conical radiometer systems, such as WindSat, AMSR, GMI or SSMI(S), all have a similar overall architecture and have exhibited significant intra-channel and inter-sensor calibration biases, due in part to the relative independence of the radiometers between the different polarizations and frequencies in the system. The COWVR system uses a broadband compact hybrid combining architecture and Electronic Polarization Basis Rotation to minimize the number of free calibration parameters between polarization and frequencies, as well as providing a definitive calibration reference from the modulation of the mean polarized signal from the Earth. This second calibration advantage arises because the sensor modulates the incoming polarized signal at the input antenna aperture in a known way based only on the instrument geometry which forces relative calibration consistency between the polarimetric channels of the sensor and provides a gain and offset calibration independent of a model or other ancillary data source, which has typically been a weakness in the calibration and inter-calibration of heritage microwave sensors. This paper will give a description of the COWVR instrument and an overview of the technology demonstration mission. We will discuss the overall calibration approach for this system, its advantages over existing systems and how many of the calibration issues that impact existing satellite radiometers can be eliminated in future operational systems based on

  14. Vectors

    DEFF Research Database (Denmark)

    Boeriis, Morten; van Leeuwen, Theo

    2017-01-01

    This article revisits the concept of vectors, which, in Kress and van Leeuwen’s Reading Images (2006), plays a crucial role in distinguishing between ‘narrative’, action-oriented processes and ‘conceptual’, state-oriented processes. The use of this concept in image analysis has usually focused...... should be taken into account in discussing ‘reactions’, which Kress and van Leeuwen link only to eyeline vectors. Finally, the question can be raised as to whether actions are always realized by vectors. Drawing on a re-reading of Rudolf Arnheim’s account of vectors, these issues are outlined...

  15. Correlation-constrained and sparsity-controlled vector autoregressive model for spatio-temporal wind power forecasting

    DEFF Research Database (Denmark)

    Zhao, Yongning; Ye, Lin; Pinson, Pierre

    2018-01-01

    The ever-increasing number of wind farms has brought both challenges and opportunities in the development of wind power forecasting techniques to take advantage of interdependenciesbetweentensorhundredsofspatiallydistributedwind farms, e.g., over a region. In this paper, a Sparsity......-Controlled Vector Autoregressive (SC-VAR) model is introduced to obtain sparse model structures in a spatio-temporal wind power forecasting framework by reformulating the original VAR model into a constrained Mixed Integer Non-Linear Programming (MINLP) problem. It allows controlling the sparsity of the coefficient...... and forecasting, the original SC-VAR is modified and a Correlation-Constrained SC-VAR (CCSC-VAR) is proposed based on spatial correlation information about wind farms. Our approach is evaluated based on a case study of very-short-term forecasting for 25 wind farms in Denmark. Comparison is performed with a set...

  16. Short term prediction of the horizontal wind vector within a wake vortex warning system

    Energy Technology Data Exchange (ETDEWEB)

    Frech, M.; Holzaepfel, F.; Gerz, T. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Wessling (Germany). Inst. fuer Physik der Atmosphaere; Konopka, J. [Deutsche Flugsicherung (DFS) GmbH, Langen (Germany)

    2000-07-14

    A wake vortex warning system (WVWS) has been developed for Frankfurt airport. This airport has two parallel runways which are separated by 518 m, a distance too short to operate them independently because wake vortices may be advected to the adjacent runway. The objective of the WVWS is to enable operation with reduced separation between two aircraft approaching the parallel runways at appropriate wind conditions. The WVWS applies a statistical persistence model to predict the crosswind within a 20 minute period. One of the main problems identified in the old WVWS are discontinuities between successive forecasts. These forecast breakdowns were not acceptable to airtraffic controllers. At least part of the problem was related to the fact that the forecast was solely based on the prediction of crosswind. A new method is developed on the basis of 523 days of sonic anemometer measurements at Frankfurt airport. It is demonstrated that the prediction of the horizontal wind vector avoids these difficulties and significantly improves the system's performance. (orig.)

  17. Retrieving current and wind vectors from ATI SAR data: airborne evidence and inversion strategy

    Science.gov (United States)

    Martin, Adrien; Gommenginger, Christine; Chapron, Bertrand; Marquez, José; Doody, Sam

    2017-04-01

    Conventional and along-track interferometric (ATI) Synthetic Aperture Radar (SAR) sense the motion of the ocean surface by measuring the Doppler shift of reflected signals. Together with the water displacement associated with ocean currents, the SAR measurements are also affected by a Wind-wave induced Artefact Surface Velocity (WASV) caused by the velocity of Bragg scatterers and the orbital velocity of ocean surface gravity waves. The WASV has been modelled theoretically in past studies but has been estimated empirically only once using Envisat ASAR. Here we propose, firstly, to evaluate this WASV from airborne ATI SAR data, secondly, to validate the airborne retrieved surface current after correction of the WASV against HF radar measurements and thirdly to examine the best inversion strategy for a an Ocean Surface Current (OSC) satellite mission to retrieve accurately both the ocean surface current vector (OSCV) and the wind vector in the frame of an OSC satellite mission. The airborne ATI SAR data were acquired in the tidally dominated Irish Sea using a Wavemill-type dual-beam SAR interferometer. A comprehensive collection of airborne Wavemill data acquired in a star pattern over a well-instrumented site made it possible to estimate the magnitude and dependence on azimuth and incidence angle of the WASV. The airborne results compare favourably with those reported for Envisat ASAR, empirical model, which has been used to correct for it. Validation of the current retrieval capabilities of the proof-of-concept has been conducted against HF radar giving a precisions typically better than 0.1 m/s for surface current speed and 7° for direction. Comparisons with POLCOMS (1.8 km) indicate that the model reproduces well the overall temporal evolution but does not capture the high spatial variability of ocean surface currents at the maximum ebb flow. Airborne retrieved currents highlight a short-scale spatial variability up to 100m related to bathymetry channels, which

  18. Noise model based ν-support vector regression with its application to short-term wind speed forecasting.

    Science.gov (United States)

    Hu, Qinghua; Zhang, Shiguang; Xie, Zongxia; Mi, Jusheng; Wan, Jie

    2014-09-01

    Support vector regression (SVR) techniques are aimed at discovering a linear or nonlinear structure hidden in sample data. Most existing regression techniques take the assumption that the error distribution is Gaussian. However, it was observed that the noise in some real-world applications, such as wind power forecasting and direction of the arrival estimation problem, does not satisfy Gaussian distribution, but a beta distribution, Laplacian distribution, or other models. In these cases the current regression techniques are not optimal. According to the Bayesian approach, we derive a general loss function and develop a technique of the uniform model of ν-support vector regression for the general noise model (N-SVR). The Augmented Lagrange Multiplier method is introduced to solve N-SVR. Numerical experiments on artificial data sets, UCI data and short-term wind speed prediction are conducted. The results show the effectiveness of the proposed technique. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Qi Liu - Bulletin of Materials Science | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science. QI LIU. Articles written in Bulletin of Materials Science. Volume 34 Issue 2 April 2011 pp 183-189. Study of structural transformations and phases formation upon calcination of Zn–Ni–Al hydrotalcite nanosheets · Zhanshuang Li Yanchao Song Jun Wang Qi Liu Piaoping Yang ...

  20. Attraction of the cutaneous leishmaniasis vector Nyssomyia neivai (Diptera: Psychodidae) to host odour components in a wind tunnel

    Science.gov (United States)

    2012-01-01

    Background Laboratory studies of host-seeking olfactory behaviour in sandflies have largely been restricted to the American visceral leishmaniasis vector Lutzomyia longipalpis. In comparison, almost nothing is known about the chemical ecology of related species, which transmit American cutaneous leishmaniasis (ACL), due in part to difficulties in raising these insects in the laboratory. Understanding how ACL vectors locate their hosts will be essential to developing new vector control strategies to combat this debilitating disease. Methods This study examined host-odour seeking behaviour of the ACL vector Nyssomyia neivai (Pinto) (=Lutzomyia neivai) using a wind tunnel olfactometer. The primary aim was to determine whether field-collected female N. neivai would respond to host odours in the laboratory, thereby eliminating the need to maintain colonies of these insects for behavioural experiments. Responses to two key host odour components, 1-octen-3-ol and lactic acid, and a commercially-available mosquito lure (BG-Lure™) were assessed and compared relative to an air control. We also tested whether trials could be conducted outside of the normal evening activity period of N. neivai without impacting on fly behaviour, and whether the same flies could be used to assess baseline responses to air without affecting responses to octenol, thereby reducing the number of flies required for experiments. Results Octenol was found to both activate host-seeking behaviour and attract female N. neivai in the wind tunnel, while lactic acid elicited weaker responses of activation and attractiveness under identical conditions. The BG-Lure did not activate or attract N. neivai under test conditions. Further experiments showed that sandfly behaviour in the wind tunnel was not affected by time of day, such that experiments need not be restricted to nocturnal hours. Moreover, using the same flies to measure both baseline responses to air and attraction to test compounds did not affect

  1. On the Liu and almost unbiased Liu estimators in the presence of multicollinearity with heteroscedastic or correlated errors

    Directory of Open Access Journals (Sweden)

    Mustafa I. Alheety

    2009-11-01

    Full Text Available This paper introduces a new biased estimator, namely, almost unbiased Liu estimator (AULE of β for the multiple linear regression model with heteroscedastics and/or correlated errors and suffers from the problem of multicollinearity. The properties of the proposed estimator is discussed and the performance over the generalized least squares (GLS estimator, ordinary ridge regression (ORR estimator (Trenkler, 1984, and Liu estimator (LE (Kaçiranlnar, 2003 in terms of matrix mean square error criterion are investigated. The optimal values of d for Liu and almost unbiased Liu estimators have been obtained. Finally, a simulation study has been conducted which indicated that under certain conditions on d, the proposed estimator performed well compared to GLS, ORR and LE estimators.

  2. Buoy perspective of a high-resolution global ocean vector wind analysis constructed from passive radiometers and active scatterometers (1987-present)

    Science.gov (United States)

    Yu, Lisan; Jin, Xiangze

    2012-11-01

    The study used 126 buoy time series as a benchmark to evaluate a satellite-based daily, 0.25-degree gridded global ocean surface vector wind analysis developed by the Objectively Analyzed airs-sea Fluxes (OAFlux) project. The OAFlux winds were produced from synthesizing wind speed and direction retrievals from 12 sensors acquired during the satellite era from July 1987 onward. The 12 sensors included scatterometers (QuikSCAT and ASCAT), passive microwave radiometers (AMSRE, SSMI and SSMIS series), and the passive polarimetric microwave radiometer from WindSat. Accuracy and consistency of the OAFlux time series are the key issues examined here. A total of 168,836 daily buoy measurements were assembled from 126 buoys, including both active and archive sites deployed during 1988-2010. With 106 buoys from the tropical array network, the buoy winds are a good reference for wind speeds in low and mid-range. The buoy comparison shows that OAFlux wind speed has a mean difference of -0.13 ms-1 and an RMS difference of 0.71 ms-1, and wind direction has a mean difference of -0.55 degree and an RMS difference of 17 degrees. Vector correlation of OAFlux and buoy winds is of 0.9 and higher over almost all the sites. Influence of surface currents on the OAFlux/buoy mean difference pattern is displayed in the tropical Pacific, with higher (lower) OAFlux wind speed in regions where wind and current have the opposite (same) sign. Improved representation of daily wind variability by the OAFlux synthesis is suggested, and a decadal signal in global wind speed is evident.

  3. Full vector (3-D) inflow simulation in natural and wind farm environments using an expanded version of the SNLWIND (Veers) turbulence code

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, N.D.

    1992-11-01

    We have recently expanded the numerical turbulence simulation (SNLWIND) developed by Veers [1] to include all three components of the turbulent wind vector. We have also configured the code to simulate the characteristics of turbulent wind fields upwind and downwind of a large wind farm, as well as over uniform, flat terrain. Veers's original method only simulates the longitudinal component of the wind in neutral flow. This paper overviews the development of spectral distribution, spatial coherence, and cross correlation models used to expired the SNLWIND code to include the three components of the turbulent wind over a range of atmospheric stabilities. These models are based on extensive measurements of the turbulence characteristics immediately upwind and downwind of a large wind farm in San Gorgonio Pass, California.

  4. Full vector (3-D) inflow simulation in natural and wind farm environments using an expanded version of the SNLWIND (Veers) turbulence code

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, N.D.

    1992-11-01

    We have recently expanded the numerical turbulence simulation (SNLWIND) developed by Veers [1] to include all three components of the turbulent wind vector. We have also configured the code to simulate the characteristics of turbulent wind fields upwind and downwind of a large wind farm, as well as over uniform, flat terrain. Veers`s original method only simulates the longitudinal component of the wind in neutral flow. This paper overviews the development of spectral distribution, spatial coherence, and cross correlation models used to expired the SNLWIND code to include the three components of the turbulent wind over a range of atmospheric stabilities. These models are based on extensive measurements of the turbulence characteristics immediately upwind and downwind of a large wind farm in San Gorgonio Pass, California.

  5. Alignment of stress, mean wind, and vertical gradient of the velocity vector

    DEFF Research Database (Denmark)

    Berg, Jacob; Mann, Jakob; Patton, E.G.

    2012-01-01

    In many applications in the atmospheric surface layer the turbulent-viscosity hypothesis is applied, i.e. the stress vector can be described through the vertical gradient of velocity. In the atmospheric surface layer, where the Coriolis force and baroclinic effects are considered negligible...

  6. Quadrotor Thrust Vectoring Control with Time Optimal Trajectory Planning in Constant Wind Fields

    NARCIS (Netherlands)

    Silva, Joao Paulo; de Wagter, C.; de Croon, G.C.H.E.

    2017-01-01

    This paper proposes a trajectory planning and control strategy to optimally visit a given set of waypoints in the presence of wind. First, aerodynamic properties of quadrotors which affect trajectory planning and tracking performance are investigated. Blade flapping, induced and parasitic drag are

  7. Evaluation of HY-2A Scatterometer Wind Vectors Using Data from Buoys, ERA-Interim and ASCAT during 2012–2014

    Directory of Open Access Journals (Sweden)

    Jianyong Xing

    2016-05-01

    Full Text Available The first Chinese operational Ku-band scatterometer on board Haiyang-2A (HY-2A, launched in August 2011, is designed for monitoring the global ocean surface wind. This study estimates the quality of the near-real-time (NRT retrieval wind speed and wind direction from the HY-2A scatterometer for 36 months from 2012 to 2014. We employed three types of sea-surface wind data from oceanic moored buoys operated by the National Data Buoy Center (NDBC and the Tropical Atmospheric Ocean project (TAO, the European Centre for Medium Range Weather Forecasting (ECMWF reanalysis data (ERA-Interim, and the advanced scatterometer (ASCAT to calculate the error statistics including mean bias, root mean square error (RMSE, and standard deviation. In addition, the rain effects on the retrieval winds were investigated using collocated Climate Prediction Center morphing method (CMORPH precipitation data. All data were collocated with the HY-2A scatterometer wind data for comparison. The quality performances of the HY-2A NRT wind vectors data (especially the wind speeds were satisfactory throughout the service period. The RMSEs of the HY-2A wind speeds relative to the NDBC, TAO, ERA-Interim, and ASCAT data were 1.94, 1.73, 2.25, and 1.62 m·s−1, respectively. The corresponding RMSEs of the wind direction were 46.63°, 43.11°, 39.93°, and 47.47°, respectively. The HY-2A scatterometer overestimated low wind speeds, especially under rainy conditions. Rain exerted a diminishing effect on the wind speed retrievals with increasing wind speed, but its effect on wind direction was robust at low and moderate wind speeds. Relative to the TAO buoy data, the RMSEs without rain effect were reduced to 1.2 m·s−1 and 39.68° for the wind speed direction, respectively, regardless of wind speed. By investigating the objective laws between rain and the retrieval winds from HY-2A, we could improve the quality of wind retrievals through future studies.

  8. a comparative study of some robust ridge and liu estimators

    African Journals Online (AJOL)

    Dr A.B.Ahmed

    ABSTRACT. In multiple linear regression analysis, multicollinearity and outliers are two main problems. When multicollinearity exists, biased estimation techniques such as Ridge and Liu Estimators are preferable to Ordinary Least Square. On the other hand, when outliers exist in the data, robust estimators like M, MM, LTS ...

  9. A comparative study of some robust ridge and liu estimators ...

    African Journals Online (AJOL)

    In multiple linear regression analysis, multicollinearity and outliers are two main problems. When multicollinearity exists, biased estimation techniques such as Ridge and Liu Estimators are preferable to Ordinary Least Square. On the other hand, when outliers exist in the data, robust estimators like M, MM, LTS and S ...

  10. The adaptive synchronization of fractional-order Liu chaotic system ...

    Indian Academy of Sciences (India)

    In this paper, the chaos control and the synchronization of two fractional-order Liu chaotic systems with unknown parameters are studied. According to the Lyapunov stabilization theory and the adaptive control theorem, the adaptive control rule is obtained for the described error dynamic stabilization. Using the adaptive rule ...

  11. The adverse reaction of chitooligosaccharides in rats | Liu | African ...

    African Journals Online (AJOL)

    The adverse reaction of chitooligosaccharides in rats. A Liu, K Sun, C Si, Z Zhu, W Zhang. Abstract. In this study, hair removal effect after subcutaneous injection of chitooligosaccharides in mice was investigated. Different methods of observation of hair removal, tissue slices and detection of hematological parameters, like ...

  12. The influence of small-scale sea surface temperature gradients on surface vector winds and subsequent impacts on oceanic Ekman pumping

    Science.gov (United States)

    Hughes, Paul J.

    Satellite observations have revealed a small-scale (air--sea coupling in regions of strong sea surface temperature (SST) gradients (e.g., fronts, currents, eddies, and tropical instability waves), where the surface wind and wind stress are modified. Surface winds and wind stresses are persistently higher over the warm side of the SST front compared to the cool side, causing perturbations in the dynamically and thermodynamically curl and divergence fields. Capturing this small-scale SST--wind variability is important because it can significantly impact both local and remote (i.e., large scale) oceanic and atmospheric processes. The SST--wind relationship is not well represented in numerical weather prediction (NWP) and climate models, and the relative importance of the physical processes that are proposed to be responsible for this relationship is actively and vehemently debated. This study focuses on the physical mechanisms that are primarily responsible for the SST-induced changes in surface wind and wind stress, and on the physical implication on ocean forcing through Ekman pumping. The roles that SST-induced atmospheric baroclinicity and boundary-layer stability play in modifying the surface vector wind in regions of strong SST gradients are examined with an idealized model. Modeled changes in surface wind speed due to changes in atmospheric boundary-layer stability and baroclinicity are largely between -2.0 and 2.0 m s-1, which is consistent with past observational findings. The baroclinic-related changes in the surface vector wind are found to have a largely linear dependence on the SST gradient, whereas the stability-related changes are highly non-linear. The linearity of the baroclinic impacts matches that of the observed (satellite and in situ) SST--wind relationship. This result suggests that the baroclinic-related mechanism is the leading factor in driving the observed surface wind response to strong open ocean SST fronts on scales greater than 25 km

  13. Maximum power extraction under different vector-control schemes and grid-synchronization strategy of a wind-driven Brushless Doubly-Fed Reluctance Generator.

    Science.gov (United States)

    Mousa, Mohamed G; Allam, S M; Rashad, Essam M

    2018-01-01

    This paper proposes an advanced strategy to synchronize the wind-driven Brushless Doubly-Fed Reluctance Generator (BDFRG) to the grid-side terminals. The proposed strategy depends mainly upon determining the electrical angle of the grid voltage, θ v and using the same transformation matrix of both the power winding and grid sides to ensure that the generated power-winding voltage has the same phase-sequence of the grid-side voltage. On the other hand, the paper proposes a vector-control (power-winding flux orientation) technique for maximum wind-power extraction under two schemes summarized as; unity power-factor operation and minimum converter-current. Moreover, a soft-starting method is suggested to avoid the employed converter over-current. The first control scheme is achieved by adjusting the command power-winding reactive power at zero for a unity power-factor operation. However, the second scheme depends on setting the command d-axis control-winding current at zero to maximize the ratio of the generator electromagnetic-torque per the converter current. This enables the system to get a certain command torque under minimum converter current. A sample of the obtained simulation and experimental results is presented to check the effectiveness of the proposed control strategies. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  14. Short-Term Wind Speed Forecasting Using the Data Processing Approach and the Support Vector Machine Model Optimized by the Improved Cuckoo Search Parameter Estimation Algorithm

    Directory of Open Access Journals (Sweden)

    Chen Wang

    2016-01-01

    Full Text Available Power systems could be at risk when the power-grid collapse accident occurs. As a clean and renewable resource, wind energy plays an increasingly vital role in reducing air pollution and wind power generation becomes an important way to produce electrical power. Therefore, accurate wind power and wind speed forecasting are in need. In this research, a novel short-term wind speed forecasting portfolio has been proposed using the following three procedures: (I data preprocessing: apart from the regular normalization preprocessing, the data are preprocessed through empirical model decomposition (EMD, which reduces the effect of noise on the wind speed data; (II artificially intelligent parameter optimization introduction: the unknown parameters in the support vector machine (SVM model are optimized by the cuckoo search (CS algorithm; (III parameter optimization approach modification: an improved parameter optimization approach, called the SDCS model, based on the CS algorithm and the steepest descent (SD method is proposed. The comparison results show that the simple and effective portfolio EMD-SDCS-SVM produces promising predictions and has better performance than the individual forecasting components, with very small root mean squared errors and mean absolute percentage errors.

  15. [Preliminary study on Professor SUN Liu-he's academic thought].

    Science.gov (United States)

    Sun, Guo-Sheng; Zhang, Jing-Feng

    2005-07-01

    Professor SUN Liu-he has been engaged in scientific research, clinical and teaching works for tens years and he is a meticulous scholar with great learning, rich clinical experience and great theoretical attainments. In clinical practice of many years, he summarizes and develops Kangai Plaster, Kangai Fushui Plaster, Ai tong Ling Plaster, and so on for acupoint sticking to treat tumors, and establishes Nu-needle hot-reinforcing method and Ti-Yun reducing method, enriching contents of needling methods, and he is good at application of specific points, established points and channel acupoints to treat refractory diseases with good results.

  16. On the Improvement of Convergence Performance for Integrated Design of Wind Turbine Blade Using a Vector Dominating Multi-objective Evolution Algorithm

    Science.gov (United States)

    Wang, L.; Wang, T. G.; Wu, J. H.; Cheng, G. P.

    2016-09-01

    A novel multi-objective optimization algorithm incorporating evolution strategies and vector mechanisms, referred as VD-MOEA, is proposed and applied in aerodynamic- structural integrated design of wind turbine blade. In the algorithm, a set of uniformly distributed vectors is constructed to guide population in moving forward to the Pareto front rapidly and maintain population diversity with high efficiency. For example, two- and three- objective designs of 1.5MW wind turbine blade are subsequently carried out for the optimization objectives of maximum annual energy production, minimum blade mass, and minimum extreme root thrust. The results show that the Pareto optimal solutions can be obtained in one single simulation run and uniformly distributed in the objective space, maximally maintaining the population diversity. In comparison to conventional evolution algorithms, VD-MOEA displays dramatic improvement of algorithm performance in both convergence and diversity preservation for handling complex problems of multi-variables, multi-objectives and multi-constraints. This provides a reliable high-performance optimization approach for the aerodynamic-structural integrated design of wind turbine blade.

  17. Necessary LIU studies in the injectors during 2012

    International Nuclear Information System (INIS)

    Rumolo, G.; Bartosik, H.; Papaphilippou, Y.

    2012-01-01

    A significant fraction of the Machine Development (MD) time in the LHC injectors in 2011 was devoted to the study of the intensity limitations in the injectors (e.g. space charge effects in PS and SPS, electron cloud effects in the PS and SPS, single bunch and multi-bunch instabilities in PS and SPS, emittance preservation across the injector chain, etc.). The main results achieved in 2011 are presented as well as the questions that still remain unresolved and are of relevance for the LHC Injector Upgrade (LIU) project. 2012 MD will also continue exploring the potential of scenarios that might become operational in the future, like the development of a low gamma transition optics in the SPS or alternative production schemes for the LHC beams in the PS. A tentative prioritized list of studies is provided. (authors)

  18. Pharmacological Evaluation of LiuWei Zhuanggu Granules in Rats

    Directory of Open Access Journals (Sweden)

    Haiming Zhu

    2012-07-01

    Full Text Available Many commonly consumed foods, herbs and spices contain a complex array of naturally occurring bioactive molecules called phytochemicals, which may confer health benefits. In this study, the impact of LiuWei Zhuanggu Granules (LWZGG on mineral metabolism in osteopenia development was evaluated. Results showed that serum estrogen, bone gla protein (BGP, and calcitonin (CT levels, bone Ca, Zn and Cu levels, femur, lumbar vertebrae and trabecular bone density, tibia maximum stress and maximum bending strength were increased, and serum parathyroid hormone (PTH, serum and urine Ca, Zn and Cu levels were decreased in rat bone. It can be concluded that LWZGG is useful to improve bone quality in ovariectomized (OVX rats.

  19. Necessary LIU studies in the injectors during 2012

    CERN Document Server

    Rumolo, G; Papaphilippou, Y

    2012-01-01

    A significant fraction of the Machine Development (MD) time in the LHC injectors in 2011 was devoted to the study of the intensity limitations in the injectors (e.g. space charge effects in PS and SPS, electron cloud effects in the PS and SPS, single bunch and multi-bunch instabilities in PS and SPS, emittance preservation across the injector chain, etc.). The main results achieved in 2011 will be presented as well as the questions that still remain unresolved and are of relevance for the LIU project. 2012 MDs will also continue exploring the potential of scenarios that might become operational in the future, like the development of a low gamma transition optics in the SPS or alternative production schemes for the LHC beams in the PS. A tentative prioritized list of studies is provided.

  20. Comparison Between Wind Power Prediction Models Based on Wavelet Decomposition with Least-Squares Support Vector Machine (LS-SVM and Artificial Neural Network (ANN

    Directory of Open Access Journals (Sweden)

    Maria Grazia De Giorgi

    2014-08-01

    Full Text Available A high penetration of wind energy into the electricity market requires a parallel development of efficient wind power forecasting models. Different hybrid forecasting methods were applied to wind power prediction, using historical data and numerical weather predictions (NWP. A comparative study was carried out for the prediction of the power production of a wind farm located in complex terrain. The performances of Least-Squares Support Vector Machine (LS-SVM with Wavelet Decomposition (WD were evaluated at different time horizons and compared to hybrid Artificial Neural Network (ANN-based methods. It is acknowledged that hybrid methods based on LS-SVM with WD mostly outperform other methods. A decomposition of the commonly known root mean square error was beneficial for a better understanding of the origin of the differences between prediction and measurement and to compare the accuracy of the different models. A sensitivity analysis was also carried out in order to underline the impact that each input had in the network training process for ANN. In the case of ANN with the WD technique, the sensitivity analysis was repeated on each component obtained by the decomposition.

  1. Evaluation of wind vectors measured by QuikSCAT using ocean buoy data along the Galician coast (NW Iberian Peninsula)

    Science.gov (United States)

    Alvarez, I.; Gomez-Gesteira, M.; deCastro, M.; Sousa, M. C.; Dias, J. M.; Santos, F.

    2012-04-01

    Wind above sea surface constitutes a key parameter to analyze coastal phenomena, like upwelling in the NW part of the Iberian Peninsula. The present work analyzes the accuracy of QuikSCAT for the period 2000-2009 by comparing satellite data with in situ data from three buoys placed along the NW coast of the Iberian Peninsula. The use of these long data series has two main objectives, on the one hand, the margin of error diminishes with the extent of the series and, on the other hand, it allows capturing the high inter-annual variability of the area. According to previous studies, the wet season is characterized by a high variability, in such a way that wind patterns change from year to year. The comparison confirms a low skill of QuikSCAT for low speed winds (<3 m/s) as previously pointed out by other authors. Once these winds were discarded, QuikSCAT revealed a higher accuracy for winds within the range 6-12 m/s. In direction, winds blowing from coast seem to be less accurately calculated by the satellite. Statistical results were similar for the three buoys in spite of the different coastal orientations. In average, the RMSE and bias for wind speed were 1.5 m/s and 0.2 m/s, respectively. Statistical data were also similar for wind direction, with the mean RMSE on the order of 34° and the mean bias on the order of 4° in absolute value. These statistical parameters are at least as accurate as those calculated in other near-shore areas all over the world. In particular, the bias was observed to be lower (in absolute value) than measured by most of the authors, which is possibly due to the high percentage of sampled winds lying within the interval [6-12] m/s, where satellite measurements are more accurate.

  2. On the Performance of Principal Component Liu-Type Estimator under the Mean Square Error Criterion

    Directory of Open Access Journals (Sweden)

    Jibo Wu

    2013-01-01

    Full Text Available Wu (2013 proposed an estimator, principal component Liu-type estimator, to overcome multicollinearity. This estimator is a general estimator which includes ordinary least squares estimator, principal component regression estimator, ridge estimator, Liu estimator, Liu-type estimator, r-k class estimator, and r-d class estimator. In this paper, firstly we use a new method to propose the principal component Liu-type estimator; then we study the superior of the new estimator by using the scalar mean squares error criterion. Finally, we give a numerical example to show the theoretical results.

  3. Correlation-constrained and sparsity-controlled vector autoregressive model for spatio-temporal wind power forecasting

    DEFF Research Database (Denmark)

    Zhao, Yongning; Ye, Lin; Pinson, Pierre

    2018-01-01

    and forecasting, the original SC-VAR is modified and a Correlation-Constrained SC-VAR (CCSC-VAR) is proposed based on spatial correlation information about wind farms. Our approach is evaluated based on a case study of very-short-term forecasting for 25 wind farms in Denmark. Comparison is performed with a set...... of traditional local methods and spatio-temporal methods. The results obtained show the proposed CCSC-VAR has better overall performance than both the original SC-VAR and other benchmark methods, taking into account all evaluation indicators, including sparsitycontrol ability, sparsity, accuracy and efficiency...

  4. On the Witt vector Frobenius

    DEFF Research Database (Denmark)

    Davis, Christopher James; Kedlaya, Kiran

    2014-01-01

    We study the kernel and cokernel of the Frobenius map on the p-typical Witt vectors of a commutative ring, not necessarily of characteristic p. We give many equivalent conditions to surjectivity of the Frobenius map on both finite and infinite length Witt vectors. In particular, surjectivity...... on finite Witt vectors turns out to be stable under certain integral extensions; this provides a clean formulation of a strong generalization of Faltings’s almost purity theorem from p-adic Hodge theory, incorporating recent improvements by Kedlaya–Liu and by Scholze....

  5. Combining dispersion modelling with synoptic patterns to understand the wind-borne transport into the UK of the bluetongue disease vector.

    Science.gov (United States)

    Burgin, Laura; Ekström, Marie; Dessai, Suraje

    2017-07-01

    Bluetongue, an economically important animal disease, can be spread over long distances by carriage of insect vectors (Culicoides biting midges) on the wind. The weather conditions which influence the midge's flight are controlled by synoptic scale atmospheric circulations. A method is proposed that links wind-borne dispersion of the insects to synoptic circulation through the use of a dispersion model in combination with principal component analysis (PCA) and cluster analysis. We illustrate how to identify the main synoptic situations present during times of midge incursions into the UK from the European continent. A PCA was conducted on high-pass-filtered mean sea-level pressure data for a domain centred over north-west Europe from 2005 to 2007. A clustering algorithm applied to the PCA scores indicated the data should be divided into five classes for which averages were calculated, providing a classification of the main synoptic types present. Midge incursion events were found to mainly occur in two synoptic categories; 64.8% were associated with a pattern displaying a pressure gradient over the North Atlantic leading to moderate south-westerly flow over the UK and 17.9% of the events occurred when high pressure dominated the region leading to south-easterly or easterly winds. The winds indicated by the pressure maps generally compared well against observations from a surface station and analysis charts. This technique could be used to assess frequency and timings of incursions of virus into new areas on seasonal and decadal timescales, currently not possible with other dispersion or biological modelling methods.

  6. Directional Bias of TAO Daily Buoy Wind Vectors in the Central Equatorial Pacific Ocean from November 2008 to January 2010

    Directory of Open Access Journals (Sweden)

    Ge Peng

    2014-07-01

    Full Text Available This article documents a systematic bias in surface wind directions between the TAO buoy measurements at 0°, 170°W and the ECMWF analysis and forecasts. This bias was of the order 10° and persisted from November 2008 to January 2010, which was consistent with a post-recovery calibration drift in the anemometer vane. Unfortunately, the calibration drift was too time-variant to be used to correct the data so the quality flag for this deployment was adjusted to reflect low data quality. The primary purpose of this paper is to inform users in the modelling and remote-sensing community about this systematic, persistent wind directional bias, which will allow users to make an educated decision on using the data and be aware of its potential impact to their downstream product quality. The uncovering of this bias and its source demonstrates the importance of continuous scientific oversight and effective user-data provider communication in stewarding scientific data. It also suggests the need for improvement in the ability of buoy data quality control procedures of the TAO and ECMWF systems to detect future wind directional systematic biases such as the one described here.

  7. Word population analysis and other evidences indicate that Shiji was amended by Liu Xiang

    Science.gov (United States)

    Chi, Ting-Ting; Wang, Shih-Chieh; Hu, Chin-Kun

    2015-11-01

    Shiji prepared by Shima Qian in Western Han Dynasty (202 BC-9 AD) was the most famous historical book in historical China. The current version of Shiji contains 130 chapters, including 10 chapters which contains some parts starting with the sentence ;Mr. Chu said …;; such parts were considered to be written by Chu Shaosun by Chang Yen in the Three Kingdoms Period (220-280 AD), which was widely accepted. We have analyzed the word population in Shiji and books written by Liu Xiang (77 BC-6 BC) in Western Han Dynasty, who was a member of the royal family. Our results and other evidences indicate that the parts of Shiji starting with the sentence ;Mr. Chu said …; were prepared by Liu Xiang. The other evidences include (1) The ending year of the events mentioned in ;Mr. Chu said...; was considered to be 47 BC, the second year of Emperor Yuan (as Emperor in 48 BC-32 BC) of Western Han Dynasty, and in the same year Liu Xiang was put into a jail, then left power center for many years. Such coincidence suggests that Liu Xiang wrote the parts ;Mr. Chu said …; in Shiji. (2) Liu Xiang's education, interest, and writings are quite consistent with the parts with ;Mr. Chu said …; in Shiji. On the other hand, one cannot find such a connection with Chu Shaosun, who did not have any other identified writings for comparison.

  8. Modified Liu-Carter Compression Model for Natural Clays with Various Initial Water Contents

    Directory of Open Access Journals (Sweden)

    Sen Qian

    2016-01-01

    Full Text Available The initial water content has a significant effect on the compression behaviour of reconstituted clays. This effect has to be considered in the Liu-Carter model to ensure the addition voids ratio only related to soil structure. A modified Liu-Carter compression model is proposed by introducing the empirical equations for reconstituted clays at different initial water contents into the Liu-Carter model. The proposed model is verified against the experimental results from the literature. The simulations by the proposed method are also compared with that by old method where the influence of initial water content is not considered. The results show that the predicted virgin compression curves of natural clays are similar, but the values of b and Δey may be very different.

  9. Proof and Pedagogy in Ancient China: Examples from Liu Hui's Commentary on "JIU ZHANG SUAN SHU".

    Science.gov (United States)

    Siu, Man-Keung

    1993-01-01

    Illustrates the pedagogical implications embodied in Liu Hui's discussion on the ancient Chinese mathematical classic "JIU ZHANG SUAN SHU" (Nine Chapters on the Mathematical Art) with respect to aspects of proof and, more generally, the role of proof in mathematics. Provides examples involving area and volume. (Contains 25 references.)…

  10. Liu et al., Afr J Tradit Complement Altern Med. (2016) 13(3):230-242 ...

    African Journals Online (AJOL)

    immunomodulatory by promoting splenic lymphocyte proliferation and stimulating the secretion of cytokines IL-2 and IFN-γ, as well as free radical (DPPH) ... As a clinical preparation, it has been used to treat lung cancer, liver cancer and gastric cancer, and also used to relieve the pain caused by chemotherapy (Liu et al., ...

  11. Chasing the Ghost of Melesina Trench: A film by Qina Liu in collaboration with Katharine Kittredge

    Directory of Open Access Journals (Sweden)

    Katherine Kittredge

    2013-04-01

    Full Text Available Filmmaker Qina Liu has created a short documentary about Katharine Kittredge's decade-long quest to learn about the life and work of Anglo-Irish diarist and poet Melesina Trench. The story tells of remarkable coincidences, documents lost and found, and the emergence of Trench's descendants in the project's final chapter.

  12. Segmentation of Handwritten Chinese Character Strings Based on improved Algorithm Liu

    Directory of Open Access Journals (Sweden)

    Zhihua Cai

    2014-09-01

    Full Text Available Algorithm Liu attracts high attention because of its high accuracy in segmentation of Japanese postal address. But the disadvantages, such as complexity and difficult implementation of algorithm, etc. have an adverse effect on its popularization and application. In this paper, the author applies the principles of algorithm Liu to handwritten Chinese character segmentation according to the characteristics of the handwritten Chinese characters, based on deeply study on algorithm Liu.In the same time, the author put forward the judgment criterion of Segmentation block classification and adhering mode of the handwritten Chinese characters.In the process of segmentation, text images are seen as the sequence made up of Connected Components (CCs, while the connected components are made up of several horizontal itinerary set of black pixels in image. The author determines whether these parts will be merged into segmentation through analyzing connected components. And then the author does image segmentation through adhering mode based on the analysis of outline edges. Finally cut the text images into character segmentation. Experimental results show that the improved Algorithm Liu obtains high segmentation accuracy and produces a satisfactory segmentation result.

  13. Possible Outflow Formation in the Central Engine of GRBs Tong Liu ...

    Indian Academy of Sciences (India)

    Astr. (2011) 32, 285–287 c Indian Academy of Sciences. Possible Outflow Formation in the Central Engine of GRBs. Tong Liu, Wei-Min Gu. ∗. & Ju-Fu Lu. Department of Physics and Institute of Theoretical Physics and Astrophysics,. Xiamen University, Xiamen, Fujian 361005, China. ∗ e-mail: guwm@xmu.edu.cn. Abstract.

  14. When Liu Hui Meets Archimedes: Students' Epistemological and Cultural Interpretations of Mathematics

    Science.gov (United States)

    Liu, Po-Hung

    2014-01-01

    The present study aimed to investigate in what way and to what extent Taiwanese college students' epistemological views of mathematics had evolved during a history-based liberal arts mathematics course titled: "When Liu Hui Meets Archimedes--Development of Eastern and Western Mathematics." The course was designed to help college students…

  15. γ-Rays Radiation of High Redshift Fermi Blazars WG Liu1, SH Fu2 ...

    Indian Academy of Sciences (India)

    γ-Rays Radiation of High Redshift Fermi Blazars. W. G. Liu1, S. H. Fu2, X. Zhang1, L. Ma1,∗. , Y. B. Li1 & D. R. Xiong1. 1Department of Physics, Yunnan Normal University, Kunming 650500, China. 2Yunnan Entry-Exit Inspection and Quarantine Bureau, Kunming 650228, China. ∗ e-mail: astromali@126.com. Abstract.

  16. Modelling growth of five different colour types of mink | Liu | South ...

    African Journals Online (AJOL)

    Modelling growth of five different colour types of mink. Z Liu, F Ning, Z Du, C Yang, J Fu, X Wang, X Bai. Abstract. The objective of this study was to estimate and compare the growth curve parameters for live weight of standard black, brown, mahogany, Hedlund white and sapphire minks. The data were collected from five ...

  17. Risk Characteristics of Real Estate Related Securities--An Extension of Liu and Mei (1992)

    OpenAIRE

    Hsien-hsing Liao; Jianping Mei

    1998-01-01

    This study extends from Liu and Mei (1992) by further investigation of assets, real estate related securities, which includes both equity and mortgage real estate investment trusts (REITs), the stocks of builder- and owner-companies, and mortgage-backed securities (MBSs). There are five major findings. First, expected excess returns of real estate related securities are more predictable than the expected excess returns of value-weighted stocks and bonds. Second, right market timing is importa...

  18. Assessment and Analysis of QuikSCAT Vector Wind Products for the Gulf of Mexico: A Long-Term and Hurricane Analysis

    Directory of Open Access Journals (Sweden)

    Eurico D’Sa

    2008-03-01

    Full Text Available The northern Gulf of Mexico is a region that has been frequently impacted in recent years by natural disasters such as hurricanes. The use of remote sensing data such as winds from NASA’s QuikSCAT satellite sensor would be useful for emergency preparedness during such events. In this study, the performance of QuikSCAT products, including JPL’s latest Level 2B (L2B 12.5 km swath winds, were evaluated with respect to buoy-measured winds in the Gulf of Mexico for the period January 2005 to February 2007. Regression analyses indicated better accuracy of QuikSCAT’s L2B DIRTH, 12.5 km than the Level 3 (L3, 25 km wind product. QuikSCAT wind data were compared directly with buoy data keeping a maximum time interval of 20 min and spatial interval of 0.1° (≈10 km. R2 values for moderate wind speeds were 0.88 and 0.93 for L2B, and 0.75 and 0.89 for L3 for speed and direction, respectively. QuikSCAT wind comparisons for buoys located offshore were better than those located near the coast. Hurricanes that took place during 2002-06 were studied individually to obtain regressions of QuikSCAT versus buoys for those events. Results show QuikSCAT’s L2B DIRTH wind product compared well with buoys during hurricanes up to the limit of buoy measurements. Comparisons with the National Hurricane Center (NHC best track analyses indicated QuikSCAT winds to be lower than those obtained by NHC, possibly due to rain contamination, while buoy measurements appeared to be constrained at high wind speeds. This study has confirmed good agreement of the new QuikSCAT L2B product with buoy measurements and further suggests its potential use during extreme weather conditions in the Gulf of Mexico.

  19. On Geometric Problems Related to Brown-York and Liu-Yau Quasilocal Mass

    Science.gov (United States)

    Miao, Pengzi; Shi, Yuguang; Tam, Luen-Fai

    2010-09-01

    We discuss some geometric problems related to the definitions of quasilocal mass proposed by Brown and York (Contemporary mathematics, vol 132, American Mathematical Society, Providence, pp 129-142, 1992; Phys Rev D (3) 47(4):1407-1419, 1993) and Liu and Yau (Phys Rev Lett 90(23):231102, 2003; J Am Math Soc 19(1):181-204, 2006). Our discussion consists of three parts. In the first part, we propose a new variational problem on compact manifolds with boundary, which is motivated by the study of Brown-York mass. We prove that critical points of this variation problem are exactly static metrics. In the second part, we derive a derivative formula for the Brown-York mass of a smooth family of closed two dimensional surfaces evolving in an ambient three dimensional manifold. As a by-product, we are able to write the ADM mass (Arnowitt et al. in Phys. Rev. (2), 122:997-1006, 1961) of an asymptotically flat 3-manifold as the sum of the Brown-York mass of a coordinate sphere S r and an integral of the scalar curvature plus a geometrically constructed function Φ( x) in the asymptotic region outside S r . In the third part, we prove that for any closed, spacelike, 2-surface Σ in the Minkowski space {mathbb {R}^{3,1}} for which the Liu-Yau mass is defined, if Σ bounds a compact spacelike hypersurface in {mathbb {R}^{3,1}} , then the Liu-Yau mass of Σ is strictly positive unless Σ lies on a hyperplane. We also show that the examples given by Ó Murchadha et al. (Phys Rev Lett 92:259001, 2004) are special cases of this result.

  20. [On Liu qin xi (six animal frolics) in Huai nan zi (Discourses of Master Huainanzi)].

    Science.gov (United States)

    Sun, Xiaozhong

    2014-05-01

    The six styles of the art of Daoyin recorded in Liu An's Huai nan zi (Discourses of Master Huainanzi) of the Western Han Dynasty was called the Liu qin xi which was simplified from the complicated ancient Daoyin art of bionic practice imitating the movements of six kinds of animal. Among them, the "xiong jing"imitates the erecting walking style of a bear so as to strengthen the waist and lower extremities; the "niao shen"follows the spreading of wings of a bird so as to extend the arms and legs, to train the shoulders and extremities; the "fu yu"imitates the movements of swimming and moving head of a wild duck so as to train the head and neck; the "yuan jue"imitates the jumping of a monkey among the tree branches so as to train the legs and waist; the "chi shi"imitates the streching neck movements of an eagle so as to strengthen the neck and improvement of vision; while the "hu gu"imitates the movement of turning head of a tiger so as to train one's nape and the buttock.

  1. Stakeholders Opinions on Multi-Use Deep Water Offshore Platform in Hsiao-Liu-Chiu, Taiwan.

    Science.gov (United States)

    Sie, Ya-Tsune; Château, Pierre-Alexandre; Chang, Yang-Chi; Lu, Shiau-Yun

    2018-02-06

    This paper describes a group model building activity designed to elicit the potential effects a projected multi-use deep water offshore platform may have on its local environment, including ecological and socio-economic issues. As such a platform is proposed for construction around the island of Hsiao-Liu-Chiu, Taiwan, we organized several meetings with the local stakeholders and structured the debates using group modeling methods to promote consensus. During the process, the participants iteratively built and revised a causal-loop diagram that summarizes their opinions. Overall, local stakeholders concluded that a multi-use deep water offshore marine platform might have beneficial effects for Hsiao-Liu-Chiu because more tourists and fish could be attracted by the structure, but they also raised some potential problems regarding the law in Taiwan and the design of the offshore platform, especially its resistance to extreme weather. We report the method used and the main results and insights gained during the process.

  2. Thermal and Pressure Characterization of a Wind Tunnel Force Balance Using the Single Vector System. Experimental Design and Analysis Approach to Model Pressure and Temperature Effects in Hypersonic Wind Tunnel Research

    Science.gov (United States)

    Lynn, Keith C.; Commo, Sean A.; Johnson, Thomas H.; Parker, Peter A,

    2011-01-01

    Wind tunnel research at NASA Langley Research Center s 31-inch Mach 10 hypersonic facility utilized a 5-component force balance, which provided a pressurized flow-thru capability to the test article. The goal of the research was to determine the interaction effects between the free-stream flow and the exit flow from the reaction control system on the Mars Science Laboratory aeroshell during planetary entry. In the wind tunnel, the balance was exposed to aerodynamic forces and moments, steady-state and transient thermal gradients, and various internal balance cavity pressures. Historically, these effects on force measurement accuracy have not been fully characterized due to limitations in the calibration apparatus. A statistically designed experiment was developed to adequately characterize the behavior of the balance over the expected wind tunnel operating ranges (forces/moments, temperatures, and pressures). The experimental design was based on a Taylor-series expansion in the seven factors for the mathematical models. Model inversion was required to calculate the aerodynamic forces and moments as a function of the strain-gage readings. Details regarding transducer on-board compensation techniques, experimental design development, mathematical modeling, and wind tunnel data reduction are included in this paper.

  3. Vector analysis

    CERN Document Server

    Newell, Homer E

    2006-01-01

    When employed with skill and understanding, vector analysis can be a practical and powerful tool. This text develops the algebra and calculus of vectors in a manner useful to physicists and engineers. Numerous exercises (with answers) not only provide practice in manipulation but also help establish students' physical and geometric intuition in regard to vectors and vector concepts.Part I, the basic portion of the text, consists of a thorough treatment of vector algebra and the vector calculus. Part II presents the illustrative matter, demonstrating applications to kinematics, mechanics, and e

  4. About vectors

    CERN Document Server

    Hoffmann, Banesh

    1975-01-01

    From his unusual beginning in ""Defining a vector"" to his final comments on ""What then is a vector?"" author Banesh Hoffmann has written a book that is provocative and unconventional. In his emphasis on the unresolved issue of defining a vector, Hoffmann mixes pure and applied mathematics without using calculus. The result is a treatment that can serve as a supplement and corrective to textbooks, as well as collateral reading in all courses that deal with vectors. Major topics include vectors and the parallelogram law; algebraic notation and basic ideas; vector algebra; scalars and scalar p

  5. Multichannel computerized control system of current pulses in LIU-30 electron accelerator

    CERN Document Server

    Gerasimov, A I; Kulgavchuk, V V; Pluzhnikov, A V

    2002-01-01

    In LIU-30 power linear pulsed induction electron accelerator (40 MeV, 10 kA, 25 ns) 288 radial lines with water insulation serve as energy accumulators and shapers of accelerating voltage pulses. The lines are charged simultaneously up to 500 kV using a system comprising 72 Arkadiev-Marx screened generators. To control parameter of synchronous pulses of charging current with up to 60 kA amplitude and 0.85 mu s duration in every of 72 charging circuits one applies a computer-aided system. Current pulse is recorded at output of every generator using the Rogowski coil signal from which via a cable line is transmitted to an analog-digital converter, is processed with 50 ns sampling and is recorded to a memory unit. Upon actuation of accelerator the signals are sequentially or selectively displayed and are compared with pulse typical shape

  6. Verification of the IVA4 film boiling model with the data base of Liu and Theofanous

    Energy Technology Data Exchange (ETDEWEB)

    Kolev, N.I. [Siemens AG Unternehmensbereich KWU, Erlangen (Germany)

    1998-01-01

    Part 1 of this work presents a closed analytical solution for mixed-convection film boiling on vertical walls. Heat transfer coefficients predicted by the proposed model and experimental data obtained at the Royal Institute of Technology in Sweden by Okkonen et al are compared. All data predicted are inside the {+-}10% error band, with mean averaged error being below 4% using the slightly modified analytical solution. The solution obtained is recommended for practical applications. The method presented here is used in Part 2 as a guideline for developing model for film boiling on spheres. The new semi-empirical film boiling model for spheres used in IVA4 computer code is compared with the experimental data base obtained by Liu and Theofanous. The data are predicted within {+-}30% error band. (author)

  7. Results of adjustment of electron source for the LIU-30 accelerator

    International Nuclear Information System (INIS)

    Androsov, A.V.; Kladnitskij, V.S.; Platonov, S.L.; Shvets, V.A.

    1988-01-01

    A new design of an electron source (electron gun) for the LIU-30 accelerator is described. Unlike the earlier used ones it has been made as a separate unit connected via a special adapter with increasing pulsed 300 kW transformer constructed on the base of an accelerating section. Ferromagnetic screen of a special shape and antisolenoid placed behind the cathode in a hollow of an oil-filled insulator and switched on antiparallely to the main focusing solenoid permit to diminish the gun emittance by 10-15%due to zero magnetic field in the cathode region. Various electron-optical systems were tested and that one based on the Pierse gun in which the anode orifice was covered with a wire gauze with 2.5 mm cell was chosen. 3 refs.; 1 fig

  8. Injection septa position and angle optimisation in view of the 2 GeV liu upgrade of the CERN PS

    CERN Document Server

    Serluca, HM; Forte, V; Fraser, M; Sterbini, G

    2017-01-01

    In the framework of the LHC Injector Upgrade (LIU)project the CERN PS injection kinetic energy will be up-graded from 1.4 to 2 GeV. The injection equipment, whichis already operating close to its limit, is being redesigned tocope with 30% increase in the beam rigidity. In this paper wepresent the experimental results from Machine Development(MD) studies on the present septum to explore its operationalhardware limits with respect to aperture restrictions, beamlosses and kick strengths in view of the LIU upgrade

  9. Elementary vectors

    CERN Document Server

    Wolstenholme, E Œ

    1978-01-01

    Elementary Vectors, Third Edition serves as an introductory course in vector analysis and is intended to present the theoretical and application aspects of vectors. The book covers topics that rigorously explain and provide definitions, principles, equations, and methods in vector analysis. Applications of vector methods to simple kinematical and dynamical problems; central forces and orbits; and solutions to geometrical problems are discussed as well. This edition of the text also provides an appendix, intended for students, which the author hopes to bridge the gap between theory and appl

  10. A robust combination approach for short-term wind speed forecasting and analysis – Combination of the ARIMA (Autoregressive Integrated Moving Average), ELM (Extreme Learning Machine), SVM (Support Vector Machine) and LSSVM (Least Square SVM) forecasts using a GPR (Gaussian Process Regression) model

    International Nuclear Information System (INIS)

    Wang, Jianzhou; Hu, Jianming

    2015-01-01

    With the increasing importance of wind power as a component of power systems, the problems induced by the stochastic and intermittent nature of wind speed have compelled system operators and researchers to search for more reliable techniques to forecast wind speed. This paper proposes a combination model for probabilistic short-term wind speed forecasting. In this proposed hybrid approach, EWT (Empirical Wavelet Transform) is employed to extract meaningful information from a wind speed series by designing an appropriate wavelet filter bank. The GPR (Gaussian Process Regression) model is utilized to combine independent forecasts generated by various forecasting engines (ARIMA (Autoregressive Integrated Moving Average), ELM (Extreme Learning Machine), SVM (Support Vector Machine) and LSSVM (Least Square SVM)) in a nonlinear way rather than the commonly used linear way. The proposed approach provides more probabilistic information for wind speed predictions besides improving the forecasting accuracy for single-value predictions. The effectiveness of the proposed approach is demonstrated with wind speed data from two wind farms in China. The results indicate that the individual forecasting engines do not consistently forecast short-term wind speed for the two sites, and the proposed combination method can generate a more reliable and accurate forecast. - Highlights: • The proposed approach can make probabilistic modeling for wind speed series. • The proposed approach adapts to the time-varying characteristic of the wind speed. • The hybrid approach can extract the meaningful components from the wind speed series. • The proposed method can generate adaptive, reliable and more accurate forecasting results. • The proposed model combines four independent forecasting engines in a nonlinear way.

  11. Dr Liu Yanhua, Deputy Minister of Science and Technology, Ministry of Science and Technology, People's Republic of China

    CERN Multimedia

    Patrice Loiez

    2004-01-01

    China and CERN renew co-operation agreement for a further five years. During a visit to CERN on 17 February, Liu Yanhua, the vice-minister of science and technology of the People's Republic of China, signed a new co-operation agreement with the laboratory.

  12. OW CCMP Ocean Surface Wind

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Cross-Calibrated Multi-Platform (CCMP) Ocean Surface Wind Vector Analyses (Atlas et al., 2011) provide a consistent, gap-free long-term time-series of monthly...

  13. Vector analysis

    CERN Document Server

    Brand, Louis

    2006-01-01

    The use of vectors not only simplifies treatments of differential geometry, mechanics, hydrodynamics, and electrodynamics, but also makes mathematical and physical concepts more tangible and easy to grasp. This text for undergraduates was designed as a short introductory course to give students the tools of vector algebra and calculus, as well as a brief glimpse into these subjects' manifold applications. The applications are developed to the extent that the uses of the potential function, both scalar and vector, are fully illustrated. Moreover, the basic postulates of vector analysis are brou

  14. Improving the Predictability of Severe Convective Weather Processes by Using Wind Vectors and Potential Temperature Changes: A Case Study of a Severe Thunderstorm

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2016-01-01

    Full Text Available Strong, local convective weather events are capable of causing extensive damage, but weather observation systems with limited resolution and radar monitoring can typically provide only a few minutes to hours of prior warning time. This paper presents a comprehensive case study of the cumulative evolution of several characteristic quantities during one extremely severe convective weather process. The research results indicate that the main feature of strong convective weather is the uneven distribution of thermal energy in the atmosphere, and the structure of this heat distribution determines the level of instability in the atmosphere. A vertical “clockwise rolling current” occurs in the wind field structure at the beginning of the process, and this is accompanied by a rapid drop in temperature at the top of the troposphere. When these signs occurred in the case study, radar technology was used to refine the precipitation region and spatial characteristics of the approaching storm. The height and vertical evolution of radar echoes were indicative of the characteristics of the system’s movement through space. Such findings may be useful for improving the forecasting times for strong convective weather.

  15. Geomagnetic displacement of the electron beam in the LIU-30 accelerator

    International Nuclear Information System (INIS)

    Rakityanskij, S.A.

    1987-01-01

    An influence of weak lateral magnetic field upon the motion of the intense electron beam inside a linear cylindrical vacuum channel is numerically explored. The problem is solved in the framework of a simple model with a thread-like beam. It also takes into account the charge and current of the image, induced in conducting surface of the vacuum tube. The dependence of the beam displacement from axis, caused by the lateral magnetic field, on the energy and on the degree of nonuniformity of the longitudinal focusing field is explored. A calculation of the beam displacement for the LIU-30 accelerating structure is performed. It is shown by this example that the earth magnetic field may cause a significant displacement. It is also shown that a smoothing away of the longitudinal field nonuniformities reduces the displacement by some times. A conclusion about advisability of orientation of the short accelerators along the geomagnetic lines and about indispensability of a removal of geomagnetic field in beginning parts of the long mashines is made

  16. Vector velocimeter

    DEFF Research Database (Denmark)

    2012-01-01

    The present invention relates to a compact, reliable and low-cost vector velocimeter for example for determining velocities of particles suspended in a gas or fluid flow, or for determining velocity, displacement, rotation, or vibration of a solid surface, the vector velocimeter comprising a laser...

  17. Wind energy

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This chapter discusses the role wind energy may have in the energy future of the US. The topics discussed in the chapter include historical aspects of wind energy use, the wind energy resource, wind energy technology including intermediate-size and small wind turbines and intermittency of wind power, public attitudes toward wind power, and environmental, siting and land use issues

  18. Three-Dimensional Wind Profiling of Offshore Wind Energy Areas With Airborne Doppler Lidar

    Science.gov (United States)

    Koch, Grady J.; Beyon, Jeffrey Y.; Cowen, Larry J.; Kavaya, Michael J.; Grant, Michael S.

    2014-01-01

    A technique has been developed for imaging the wind field over offshore areas being considered for wind farming. This is accomplished with an eye-safe 2-micrometer wavelength coherent Doppler lidar installed in an aircraft. By raster scanning the aircraft over the wind energy area (WEA), a three-dimensional map of the wind vector can be made. This technique was evaluated in 11 flights over the Virginia and Maryland offshore WEAs. Heights above the ocean surface planned for wind turbines are shown to be within the marine boundary layer, and the wind vector is seen to show variation across the geographical area of interest at turbine heights.

  19. Cloning vector

    Science.gov (United States)

    Guilfoyle, R.A.; Smith, L.M.

    1994-12-27

    A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site. 2 figures.

  20. Cloning vector

    Science.gov (United States)

    Guilfoyle, Richard A.; Smith, Lloyd M.

    1994-01-01

    A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site.

  1. [Protocol of Miao medical LIU's infant tuina genre "Tui Wu Jing" in western Hunan province for prevention of asthma recurrence].

    Science.gov (United States)

    Li, Zhongzheng; Jia, Yuanbin; Guo, Jing; Wang, Xiaojun; Su, Shaomin; Liu, Yingying; Deng, Yu; Liu, Liangjing; Shi, Weikun; Yang, Renda

    2017-07-12

    The Miao medical LIU 's ( LIU Kaiyun ) infant tuina genre in western Hunan Province is one of the most famous infant tuina genres in China. Based on physiological and pathological characteristics of infants, generation-inhibition theory of five-elements and Miao medical's promotion-inhibition theory of five-meridians, the tuina protocol of " Tui Wu Jing " was flexibly adjusted; according to different constitution types, including lung-deficiency type, spleen-deficiency type, kidney-deficiency type, qi -deficiency type, yin -deficiency type, yang -deficiency type, phlegm-wet type, phlegm-heat type, different protocols were adopted to prevent or reduce the asthma recurrence and reach the aim of regulating constitution and disease prevention.

  2. On a model of mixtures with internal variables: Extended Liu procedure for the exploitation of the entropy principle

    Directory of Open Access Journals (Sweden)

    Francesco Oliveri

    2016-01-01

    Full Text Available The exploitation of second law of thermodynamics for a mixture of two fluids with a scalar internal variable and a first order nonlocal state space is achieved by using the extended Liu approach. This method requires to insert as constraints in the entropy inequality either the field equations or their gradient extensions. Consequently, the thermodynamic restrictions imposed by the entropy principle are derived without introducing extra terms neither in the energy balance equation nor in the entropy inequality.

  3. Liu Tungsheng: A geologist from a traditional Chinese cultural background who became an international star of science

    Science.gov (United States)

    Zhang, Yuhong; Guan, Li; Liu, Qiang

    2018-04-01

    Liu Tungsheng (1917-2008) resumed his scientific career and became actively involved on the international stage in the field of Quaternary Sciences after 1982, at the age of 65, following Deng Xiaoping's 'Reform and Open Up' policy, after his first international publication of China loess research published in 1950s. Though his best known contribution to Quaternary research is his pioneering study of the extensive loess deposits of China, several other important scientific contributions are less widely known, as they were published in Chinese. By studying about 400 well-preserved fieldwork notebooks left by Liu Tungsheng, as well as many biographical and personal photographic collections, we have mapped his remarkable life during his 91-year journey and the contributions to geoscience. From a historical point of view, Liu Tungsheng created a unique chapter in the history of modern geological science in China in his role as a geologist emerging from a traditional Chinese cultural background who became a star on the international scientific stage.

  4. Vector geometry

    CERN Document Server

    Robinson, Gilbert de B

    2011-01-01

    This brief undergraduate-level text by a prominent Cambridge-educated mathematician explores the relationship between algebra and geometry. An elementary course in plane geometry is the sole requirement for Gilbert de B. Robinson's text, which is the result of several years of teaching and learning the most effective methods from discussions with students. Topics include lines and planes, determinants and linear equations, matrices, groups and linear transformations, and vectors and vector spaces. Additional subjects range from conics and quadrics to homogeneous coordinates and projective geom

  5. Retrieval of vertical wind profiles during monsoon from satellite ...

    Indian Academy of Sciences (India)

    algorithm which ensures the retrieval of vertical profiles of winds using satellite tracked cloud motion vector winds. Under the assumption that accurate measurements of wind are available at the above mentioned levels, the r.m.s. error of retrieval of each component of wind is estimated to range between. 2 msю1 and 6 ...

  6. VECTOR INTEGRATION

    NARCIS (Netherlands)

    Thomas, E. G. F.

    2012-01-01

    This paper deals with the theory of integration of scalar functions with respect to a measure with values in a, not necessarily locally convex, topological vector space. It focuses on the extension of such integrals from bounded measurable functions to the class of integrable functions, proving

  7. Liu Na’ou And The 1930s Soft Film Movement: A New Approach In Revisionist Chinese Film Historiography

    OpenAIRE

    Donna Ong

    2013-01-01

    This essay analyzes how the 1930s Chinese “Soft Film” movement emerged and developed in film historiography, and finds it is a discursive formation by the Leftists to create an ideological enemy that serves to define its own group’s identity through a struggle against an “other”. It challenges the naming of “Soft Film” through examining documents beyond the official archive. Unearthing the film writings of Liu Na’ou as the movement’s leading figure is a good entry point into excavating the hi...

  8. An introduction to vectors, vector operators and vector analysis

    CERN Document Server

    Joag, Pramod S

    2016-01-01

    Ideal for undergraduate and graduate students of science and engineering, this book covers fundamental concepts of vectors and their applications in a single volume. The first unit deals with basic formulation, both conceptual and theoretical. It discusses applications of algebraic operations, Levi-Civita notation, and curvilinear coordinate systems like spherical polar and parabolic systems and structures, and analytical geometry of curves and surfaces. The second unit delves into the algebra of operators and their types and also explains the equivalence between the algebra of vector operators and the algebra of matrices. Formulation of eigen vectors and eigen values of a linear vector operator are elaborated using vector algebra. The third unit deals with vector analysis, discussing vector valued functions of a scalar variable and functions of vector argument (both scalar valued and vector valued), thus covering both the scalar vector fields and vector integration.

  9. Wind Energy

    International Nuclear Information System (INIS)

    Rodriguez D, J.M.

    1998-01-01

    The general theory of the wind energy conversion systems is presented. The availability of the wind resource in Colombia and the ranges of the speed of the wind in those which is possible economically to use the wind turbines are described. It is continued with a description of the principal technological characteristics of the wind turbines and are split into wind power and wind-powered pumps; and its use in large quantities grouped in wind farms or in autonomous systems. Finally, its costs and its environmental impact are presented

  10. Distributed approximating functional fit of the H3 ab initio potential-energy data of Liu and Siegbahn

    International Nuclear Information System (INIS)

    Frishman, A.; Hoffman, D.K.; Kouri, D.J.

    1997-01-01

    We report a distributed approximating functional (DAF) fit of the ab initio potential-energy data of Liu [J. Chem. Phys. 58, 1925 (1973)] and Siegbahn and Liu [ibid. 68, 2457 (1978)]. The DAF-fit procedure is based on a variational principle, and is systematic and general. Only two adjustable parameters occur in the DAF leading to a fit which is both accurate (to the level inherent in the input data; RMS error of 0.2765 kcal/mol) and smooth (open-quotes well-tempered,close quotes in DAF terminology). In addition, the LSTH surface of Truhlar and Horowitz based on this same data [J. Chem. Phys. 68, 2466 (1978)] is itself approximated using only the values of the LSTH surface on the same grid coordinate points as the ab initio data, and the same DAF parameters. The purpose of this exercise is to demonstrate that the DAF delivers a well-tempered approximation to a known function that closely mimics the true potential-energy surface. As is to be expected, since there is only roundoff error present in the LSTH input data, even more significant figures of fitting accuracy are obtained. The RMS error of the DAF fit, of the LSTH surface at the input points, is 0.0274 kcal/mol, and a smooth fit, accurate to better than 1cm -1 , can be obtained using more than 287 input data points. copyright 1997 American Institute of Physics

  11. Hydrogen as a vector in Mercosul for the transmission of wind power from Patagonia and as a vehicle to its overseas exportation; Hidrogeno como vector en el Mercosur para transmision de energia eolica desde la Patagonia y como vehiculo para su exportacion a ultramar

    Energy Technology Data Exchange (ETDEWEB)

    Spinadel, Erico; Gracia Nunes, Sabas Luis; Gamallo, Florencio [Buenos Aires Univ. (Argentina). Facultad de Ingenieria. GENCo - Grupo de I y D en Energias No Convencionales

    1997-12-31

    The wind resource in Patagonia is one of the most important energetic reserves in Latin America, and should be taken into account in any high-scale generation project proposed for this area. However, the direct connection of wind farms to the net introduces some unstability problems that limit the amount of admissible wind power in it. The authors`s proposal is applying all the obtained wind energy to an electrolytic process for hydrogen production, for using it later as an alternative fuel in conventional power stations. (author) 8 refs.; e-mail: postmaster at genco.uba.ar

  12. Liu Na’ou And The 1930s Soft Film Movement: A New Approach In Revisionist Chinese Film Historiography

    Directory of Open Access Journals (Sweden)

    Donna Ong

    2013-06-01

    Full Text Available This essay analyzes how the 1930s Chinese “Soft Film” movement emerged and developed in film historiography, and finds it is a discursive formation by the Leftists to create an ideological enemy that serves to define its own group’s identity through a struggle against an “other”. It challenges the naming of “Soft Film” through examining documents beyond the official archive. Unearthing the film writings of Liu Na’ou as the movement’s leading figure is a good entry point into excavating the history of the people and films associated with the label “Soft Film”. Reconstructing this “reactionary cinema” will reveal previously unknown cultural connections with classical and avant-garde Western film theories, and more importantly renovate the established Chinese film canon of the 1930s.

  13. Introduction to the special issue of "Loess and Climatic Record": Memory of Professor Liu Tungsheng for his scientific contributions and his centenary birthday

    Science.gov (United States)

    Ding, Zhongli; Derbyshire, Edward; Sun, Jimin

    2018-04-01

    This special issue is to memory Professor Liu Tungsheng for his scientific contributions and his centenary birthday. Liu Tungsheng was the former President of the International Association for Quaternary Association (INQUA), and the Honorary President of the Chinese Association for Quaternary Research (CHIQUA). Liu's best known contribution to Quaternary research is his pioneering and systematic study of the extensive loess deposits of China, which has been regarded as the best terrestrial paleoclimatic archive on the Earth. He won many international awards including the Tyler Prize for Environmental Achievement in 2002 and the Alexander von Humboldt Medal in 2007. He was an inspiring leader, one of China's, and indeed one of the world's most outstanding Earth scientists. This introduction aims to explore the personal factors behind his great achievements and reviews the papers included in this special issue from his colleagues, friends, and students.

  14. Wind Structure and Wind Loading

    DEFF Research Database (Denmark)

    Brorsen, Michael

    The purpose of this note is to provide a short description of wind, i.e. of the flow in the atmosphere of the Earth and the loading caused by wind on structures. The description comprises: causes to the generation of windhe interaction between wind and the surface of the Earthhe stochastic nature...... of windhe interaction between wind and structures, where it is shown that wind loading depends strongly on this interaction...

  15. Lidar Turbulence Measurements for Wind Energy

    DEFF Research Database (Denmark)

    Mann, Jakob; Sathe, Ameya; Gottschall, Julia

    2012-01-01

    Modeling of the systematic errors in the second-order moments of wind speeds measured by continuous-wave (ZephIR) and pulsed (WindCube) lidars is presented. These lidars use the velocity azimuth display technique to measure the velocity vector. The model is developed for the line-of-sight averaging...

  16. Lidar Turbulence Measurements for Wind Energy

    DEFF Research Database (Denmark)

    Mann, Jakob; Sathe, Ameya; Gottschall, Julia

    2012-01-01

    Modeling of the systematic errors in the second-order moments of wind speeds measured by continuous-wave (ZephIR) and pulsed (WindCube) lidars is presented. These lidars use the velocity azimuth display technique to measure the velocity vector. The model is developed for the line-of-sight averagi...

  17. An Asymmetrical Space Vector Method for Single Phase Induction Motor

    DEFF Research Database (Denmark)

    Cui, Yuanhai; Blaabjerg, Frede; Andersen, Gert Karmisholt

    2002-01-01

    the motor torque performance is not good enough. This paper addresses a new control method, an asymmetrical space vector method with PWM modulation, also a three-phase inverter is used for the main winding and the auxiliary winding. This method with PWM modulation is implemented to control the motor speed...

  18. Planned experiments and corpus based research play a complementary role. Comment on "Dependency distance: A new perspective on syntactic patterns in natural languages" by Haitao Liu et al.

    Science.gov (United States)

    Vasishth, Shravan

    2017-07-01

    This interesting and informative review by Liu and colleagues [17] in this issue covers the full spectrum of research on the idea that in natural language, dependency distance tends to be small. The authors discuss two distinct research threads: experimental work from psycholinguistics on online processes in comprehension and production, and text-corpus studies of dependency length distributions.

  19. Comparative study of the efficacy of Wright-Giemsa stain and Liu's stain in the detection of Auer rods in acute promyelocytic leukemia.

    Science.gov (United States)

    Yue, Qing Fang; Xiong, Bei; Chen, Wan Xin; Liu, Xin Yue

    2014-07-01

    In view of the importance of Auer rods in the rapid diagnosis of acute promyelocytic leukemia, we compared the results of Wright-Giemsa stain and Liu's stain (a rapid and simple stain, which is also a kind of modified Romanowsky stain) in the detection of Auer rods. This study was based on 53 cases of acute promyelocytic leukemia. Two staining methods were respectively performed on the bone marrow smears of these cases, and presence of Auer rods as well as nuclear features, cytoplasmic features and the degree of granularity of the cytoplasm were compared in each case. Our results showed that the occurrence of Auer rods as well as faggots in leukemic promyelocytes were significantly higher under Liu's stain than under Wright-Giemsa stain. Significant differences also existed in the occurrence of hypergranular cells and cytoplasmic protrusions between smears stained with Liu's stain and Wright-Giemsa stain. Liu's stain is important for the rapid diagnosis of suspicious APL, especially in recognizing Auer rods. Copyright © 2014 Elsevier GmbH. All rights reserved.

  20. Wind power

    International Nuclear Information System (INIS)

    Gipe, P.

    2007-01-01

    This book is a translation of the edition published in the USA under the title of ''wind power: renewable energy for home, farm and business''. In the wake of mass blackouts and energy crises, wind power remains a largely untapped resource of renewable energy. It is a booming worldwide industry whose technology, under the collective wing of aficionados like author Paul Gipe, is coming of age. Wind Power guides us through the emergent, sometimes daunting discourse on wind technology, giving frank explanations of how to use wind technology wisely and sound advice on how to avoid common mistakes. Since the mid-1970's, Paul Gipe has played a part in nearly every aspect of wind energy development from installing small turbines to promoting wind energy worldwide. As an American proponent of renewable energy, Gipe has earned the acclaim and respect of European energy specialists for years, but his arguments have often fallen on deaf ears at home. Today, the topic of wind power is cropping up everywhere from the beaches of Cape Cod to the Oregon-Washington border, and one wind turbine is capable of producing enough electricity per year to run 200 average American households. Now, Paul Gipe is back to shed light on this increasingly important energy source with a revised edition of Wind Power. Over the course of his career, Paul Gipe has been a proponent, participant, observer, and critic of the wind industry. His experience with wind has given rise to two previous books on the subject, Wind Energy Basics and Wind Power for Home and Business, which have sold over 50,000 copies. Wind Power for Home and Business has become a staple for both homeowners and professionals interested in the subject, and now, with energy prices soaring, interest in wind power is hitting an all-time high. With chapters on output and economics, Wind Power discloses how much you can expect from each method of wind technology, both in terms of energy and financial savings. The book updated models

  1. Liu Jun Zi Tang—A Potential, Multi-Herbal Complementary Therapy for Chemotherapy-Induced Neurotoxicity

    Directory of Open Access Journals (Sweden)

    Chun-Tang Chiou

    2018-04-01

    Full Text Available Liu Jun Zi Tang (LJZT has been used to treat functional dyspepsia and depression, suggesting its effects on gastrointestinal and neurological functions. LJZT is currently used as a complementary therapy to attenuate cisplatin-induced side effects, such as dyspepsia. However, its effect on chemotherapy-induced neuropathic pain or neurotoxicity has rarely been studied. Thus, we explored potential mechanisms underlying LJZT protection against cisplatin-induced neurotoxicity. We observed that LJZT attenuated cisplatin-induced thermal hyperalgesia in mice and apoptosis in human neuroblastoma SH-SY5Y cells. Furthermore, it also attenuated cisplatin-induced cytosolic and mitochondrial free radical formation, reversed the cisplatin-induced decrease in mitochondrial membrane potential, and increased the release of mitochondrial pro-apoptotic factors. LJZT not only activated the peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α promoter region, but also attenuated the cisplatin-induced reduction of PGC-1α expression. Silencing of the PGC-1α gene counteracted the protection of LJZT. Taken together, LJZT mediated, through anti-oxidative effect and mitochondrial function regulation, to prevent cisplatin-induced neurotoxicity.

  2. Simulating spread of Bluetongue Virus by flying vectors between hosts on pasture

    DEFF Research Database (Denmark)

    Græsbøll, Kaare; Bødker, Rene; Enøe, Claes

    2012-01-01

    and display search behavior to locate areas with hosts. We also include wind spread of vectors, host movements, and vector seasonality. Results show that temperature and seasonality of vectors determines the period in which an incursion of Bluetongue may lead to epidemic spread in Denmark. Within this period...

  3. A high resolution WRF model for wind energy forecasting

    Science.gov (United States)

    Vincent, Claire Louise; Liu, Yubao

    2010-05-01

    The increasing penetration of wind energy into national electricity markets has increased the demand for accurate surface layer wind forecasts. There has recently been a focus on forecasting the wind at wind farm sites using both statistical models and numerical weather prediction (NWP) models. Recent advances in computing capacity and non-hydrostatic NWP models means that it is possible to nest mesoscale models down to Large Eddy Simulation (LES) scales over the spatial area of a typical wind farm. For example, the WRF model (Skamarock 2008) has been run at a resolution of 123 m over a wind farm site in complex terrain in Colorado (Liu et al. 2009). Although these modelling attempts indicate a great hope for applying such models for detailed wind forecasts over wind farms, one of the obvious challenges of running the model at this resolution is that while some boundary layer structures are expected to be modelled explicitly, boundary layer eddies into the inertial sub-range can only be partly captured. Therefore, the amount and nature of sub-grid-scale mixing that is required is uncertain. Analysis of Liu et al. (2009) modelling results in comparison to wind farm observations indicates that unrealistic wind speed fluctuations with a period of around 1 hour occasionally occurred during the two day modelling period. The problem was addressed by re-running the same modelling system with a) a modified diffusion constant and b) two-way nesting between the high resolution model and its parent domain. The model, which was run with horizontal grid spacing of 370 m, had dimensions of 505 grid points in the east-west direction and 490 points in the north-south direction. It received boundary conditions from a mesoscale model of resolution 1111 m. Both models had 37 levels in the vertical. The mesoscale model was run with a non-local-mixing planetary boundary layer scheme, while the 370 m model was run with no planetary boundary layer scheme. It was found that increasing the

  4. Raster images vectorization system

    OpenAIRE

    Genytė, Jurgita

    2006-01-01

    The problem of raster images vectorization was analyzed and researched in this work. Existing vectorization systems are quite expensive, the results are inaccurate, and the manual vectorization of a large number of drafts is impossible. That‘s why our goal was to design and develop a new raster images vectorization system using our suggested automatic vectorization algorithm and the way to record results in a new universal vectorial file format. The work consists of these main parts: analysis...

  5. Kochen-Specker vectors

    International Nuclear Information System (INIS)

    Pavicic, Mladen; Merlet, Jean-Pierre; McKay, Brendan; Megill, Norman D

    2005-01-01

    We give a constructive and exhaustive definition of Kochen-Specker (KS) vectors in a Hilbert space of any dimension as well as of all the remaining vectors of the space. KS vectors are elements of any set of orthonormal states, i.e., vectors in an n-dimensional Hilbert space, H n , n≥3, to which it is impossible to assign 1s and 0s in such a way that no two mutually orthogonal vectors from the set are both assigned 1 and that not all mutually orthogonal vectors are assigned 0. Our constructive definition of such KS vectors is based on algorithms that generate MMP diagrams corresponding to blocks of orthogonal vectors in R n , on algorithms that single out those diagrams on which algebraic (0)-(1) states cannot be defined, and on algorithms that solve nonlinear equations describing the orthogonalities of the vectors by means of statistically polynomially complex interval analysis and self-teaching programs. The algorithms are limited neither by the number of dimensions nor by the number of vectors. To demonstrate the power of the algorithms, all four-dimensional KS vector systems containing up to 24 vectors were generated and described, all three-dimensional vector systems containing up to 30 vectors were scanned, and several general properties of KS vectors were found

  6. Data mining analysis of Professor Liu Shangyi’s prescription characteristics in clinical medicine for the treatment of cancer patients with stomachache

    Directory of Open Access Journals (Sweden)

    Wen-Qi Huang

    2018-01-01

    Full Text Available Objective: To analyze National Chinese Medicine Master Liu Shangyi’s prescription characteristics of clinical medicine for the treatment of cancer patients with stomachache. Methods: Data on prescriptions for cancer patients with stomachache between January 2014 and July 2016 were collected. The composing principles were analyzed by unsupervised data mining methods including Apriori algorithm in association rules and complex system entropy cluster. Results: Based on the analysis of 120 prescriptions, the frequency of each herb and association rules among the herbs were computed. Four core combinations and two new prescriptions were mined from the database. Compared to the before treatment, the clinical symptomatic grading of stomachache after treatment was lower (P < 0.001. Conclusion: Professor Liu has been successful in the treatment of cancer patients with stomachache by prescribing medication that aids in activating blood circulation, removing dampness, and alleviating pain.

  7. Vector regression introduced

    Directory of Open Access Journals (Sweden)

    Mok Tik

    2014-06-01

    Full Text Available This study formulates regression of vector data that will enable statistical analysis of various geodetic phenomena such as, polar motion, ocean currents, typhoon/hurricane tracking, crustal deformations, and precursory earthquake signals. The observed vector variable of an event (dependent vector variable is expressed as a function of a number of hypothesized phenomena realized also as vector variables (independent vector variables and/or scalar variables that are likely to impact the dependent vector variable. The proposed representation has the unique property of solving the coefficients of independent vector variables (explanatory variables also as vectors, hence it supersedes multivariate multiple regression models, in which the unknown coefficients are scalar quantities. For the solution, complex numbers are used to rep- resent vector information, and the method of least squares is deployed to estimate the vector model parameters after transforming the complex vector regression model into a real vector regression model through isomorphism. Various operational statistics for testing the predictive significance of the estimated vector parameter coefficients are also derived. A simple numerical example demonstrates the use of the proposed vector regression analysis in modeling typhoon paths.

  8. Temporal Courses in EEG Theta and Alpha Activity in the Dynamic Health Qigong Techniques Wu Qin Xi and Liu Zi Jue.

    Science.gov (United States)

    Henz, Diana; Schöllhorn, Wolfgang I

    2017-01-01

    Health Qigong is a common technique of Traditional Chinese Medicine applied to strengthen mental and physical health. Several studies report increases in EEG theta and alpha activity after meditative Qigong techniques indicating a relaxed state of mind. To date, little is known on the effects of dynamic Health Qigong techniques that comprise bodily movements on brain activity. In the current study, we compared effects of two dynamic Health Qigong techniques on EEG brain activity. Subjects performed the techniques Wu Qin Xi (five animals play) and Liu Zi Jue (six healing sounds) in a within-subjects design. Eyes-open and eyes-closed resting EEG was recorded before and immediately after each 15-min practice block. Additionally, the Profile of Mood States (POMS) questionnaire was administered at pretest, and after each 15-min practice block. Results show a decrease in alpha activity after 15 min, followed by an increase after 30 min in the Health Qigong technique Liu Zi Jue . Theta activity was decreased after 15 min, followed by an increase after 30 min in the technique Wu Qin Xi . Results of the POMS indicated an increased vigor-activity level with decreased fatigue and tension-anxiety levels in both techniques after 30 min of practice. Our results demonstrate different temporal dynamics in EEG theta and alpha activity for the Health Qigong techniques Wu Qin Xi and Liu Zi Jue . We hypothesize that the found brain activation patterns result from different attentional focusing styles and breathing techniques performed during the investigated Health Qigong techniques.

  9. Light axial vector mesons

    Science.gov (United States)

    Chen, Kan; Pang, Cheng-Qun; Liu, Xiang; Matsuki, Takayuki

    2015-04-01

    Inspired by the abundant experimental observation of axial-vector states, we study whether the observed axial-vector states can be categorized into the conventional axial-vector meson family. In this paper we carry out an analysis based on the mass spectra and two-body Okubo-Zweig-Iizuka-allowed decays. Besides testing the possible axial-vector meson assignments, we also predict abundant information for their decays and the properties of some missing axial-vector mesons, which are valuable for further experimental exploration of the observed and predicted axial-vector mesons.

  10. Wind energy

    CERN Document Server

    Woll, Kris

    2016-01-01

    Across the country, huge open spaces are covered in gently turning wind turbines. In Wind Energy, explore how these machines generate electricity, learn about the history of wind power, and discover the latest advances in the field. Easy-to-read text, vivid images, and helpful back matter give readers a clear look at this subject. Features include a table of contents, infographics, a glossary, additional resources, and an index. Aligned to Common Core Standards and correlated to state standards. Core Library is an imprint of Abdo Publishing, a division of ABDO.

  11. [Study on an outbreak of echovirus type 6 of meningitis in Liu'an city, Anhui province].

    Science.gov (United States)

    He, Shu-Chun; Xiong, Chuan-Long; Wu, Jia-Bing; Peng, Da-Yuan; Zhao, Yue-Ping

    2007-07-01

    To understand the epidemiological, clinical and etiological characteristics of an Echovirus type 6 meningitis outbreak in Jinzhai county, Liu'an city in Anhui, and to find out the proper way in controlling the aseptic meningitis outbreak. A surveillance system for aseptic meningitis was established in Jinzhai to confirm the case definition. Stool or cerebrospinal fluid (CSF) specimens from some cases were collected for entero-viruses isolation and identification. Case-control study was conducted. The case group involved patients while the controls would include: patients' classmate with same gender and the age difference was not over one year. Neutralization antibody in serum specimens were collected and tested in cases and in healthy people. 105 cases were distributed in 17 of the 30 towns in Jinzhai county while 41.0% of the cases were in Banzhuyuan town with an incidence rate of 203/10(5). Cases were clustered by school and classroom with age ranging from 3 to 15 years old and the highest as 10.9/10(5) in the 6 to 10 group. The incidence in males was 24.2/10(5) compared to 8.4/10(5) in females. The main clinic characteristics of cases were: fever, headache and vomiting. Echovirus type 6 from 25 of the 72 CSF samples (35%) was isolated. When comparing the cases group with control group, the OR of drinking home-made beverages was 4.1 (95% CI: 1.4-12.0), especially the beverages sacked by plastic bag: 3.3 (95% CI: 1.3-8.8). 6 out of 7 workers engaging in producing home-made beverages were detected to have carried Echovirus type 6 from their stool specimens. The Echovirus type 6 neutralization antibody positive rate in cases (73.5%) was significantly higher than that in 100 healthy people (46.0%) (X2 = 12. 526, P = 0.000). This episode of meningitis outbreak was caused by Echovirus type 6. The proportion of drinking home-made beverages, especially the beverages sacked by plastic bag in cases group was higher than in control group.

  12. VectorBase

    Data.gov (United States)

    U.S. Department of Health & Human Services — VectorBase is a Bioinformatics Resource Center for invertebrate vectors. It is one of four Bioinformatics Resource Centers funded by NIAID to provide web-based...

  13. Electrostatic Solitary Waves in the Solar Wind: Evidence for Instability at Solar Wind Current Sheets

    Science.gov (United States)

    Malaspina, David M.; Newman, David L.; Wilson, Lynn Bruce; Goetz, Keith; Kellogg, Paul J.; Kerstin, Kris

    2013-01-01

    A strong spatial association between bipolar electrostatic solitary waves (ESWs) and magnetic current sheets (CSs) in the solar wind is reported here for the first time. This association requires that the plasma instabilities (e.g., Buneman, electron two stream) which generate ESWs are preferentially localized to solar wind CSs. Distributions of CS properties (including shear angle, thickness, solar wind speed, and vector magnetic field change) are examined for differences between CSs associated with ESWs and randomly chosen CSs. Possible mechanisms for producing ESW-generating instabilities at solar wind CSs are considered, including magnetic reconnection.

  14. World Wind

    Data.gov (United States)

    National Aeronautics and Space Administration — World Wind allows any user to zoom from satellite altitude into any place on Earth, leveraging high resolution LandSat imagery and SRTM elevation data to experience...

  15. Custodial vector model

    DEFF Research Database (Denmark)

    Becciolini, Diego; Franzosi, Diogo Buarque; Foadi, Roshan

    2015-01-01

    We analyze the Large Hadron Collider (LHC) phenomenology of heavy vector resonances with a $SU(2)_L\\times SU(2)_R$ spectral global symmetry. This symmetry partially protects the electroweak S-parameter from large contributions of the vector resonances. The resulting custodial vector model spectrum...

  16. 78 FR 29364 - Exelon Corporation, Exelon Wind 1, LLC, Exelon Wind 2, LLC, Exelon Wind 3, LLC, Exelon Wind 4...

    Science.gov (United States)

    2013-05-20

    ...-005, QF07-257-004] Exelon Corporation, Exelon Wind 1, LLC, Exelon Wind 2, LLC, Exelon Wind 3, LLC, Exelon Wind 4, LLC, Exelon Wind 5, LLC, Exelon Wind 6, LLC, Exelon Wind 7, LLC, Exelon Wind 8, LLC, Exelon Wind 9, LLC, Exelon Wind 10, LLC, Exelon Wind 11, LLC, High Plains Wind Power, LLC v. Xcel Energy...

  17. Modeling and Control of Direct Driven PMSG for Ultra Large Wind Turbines

    OpenAIRE

    Ahmed M. Hemeida; Wael A. Farag; Osama A. Mahgoub

    2011-01-01

    This paper focuses on developing an integrated reliable and sophisticated model for ultra large wind turbines And to study the performance and analysis of vector control on large wind turbines. With the advance of power electronics technology, direct driven multi-pole radial flux PMSG (Permanent Magnet Synchronous Generator) has proven to be a good choice for wind turbines manufacturers. To study the wind energy conversion systems, it is important to develop a wind turbin...

  18. 25 November 2008 - State Councilor in charge of Science, Technology and Education Y. Liu, People's Repblic of China, visiting AMS experiment with CERN Director-General R. Aymar and AMS Collaborator Y. Yang.

    CERN Multimedia

    Maximilien Brice

    2008-01-01

    25 November 2008 - State Councilor in charge of Science, Technology and Education Y. Liu, People's Repblic of China, visiting AMS experiment with CERN Director-General R. Aymar and AMS Collaborator Y. Yang.

  19. Rotations with Rodrigues' vector

    International Nuclear Information System (INIS)

    Pina, E

    2011-01-01

    The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears to be a fundamental matrix that is used to express the components of the angular velocity, the rotation matrix and the angular momentum vector. The Hamiltonian formalism of rotational dynamics in terms of this vector uses the same matrix. The quantization of the rotational dynamics is performed with simple rules if one uses Rodrigues' vector and similar formal expressions for the quantum operators that mimic the Hamiltonian classical dynamics.

  20. Understanding Inertial and Frequency Response of Wind Power Plants: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, E.; Gevorgian, V.; Singh, M.; Santoso, S.

    2012-07-01

    The objective of this paper is to analyze and quantify the inertia and frequency responses of wind power plants with different wind turbine technologies (particularly those of fixed speed, variable slip with rotor-resistance controls, and variable speed with vector controls).

  1. A bistatic sodar for precision wind profiling in complex terrain

    DEFF Research Database (Denmark)

    Bradley, Stuart; Hünerbein, Sabine Von; Mikkelsen, Torben

    2012-01-01

    A new ground-based wind profiling technology-a scanned bistatic sodar-is described. The motivation for this design is to obtain a "mastlike"wind vector profile in a single atmospheric column extending from the ground to heights of more than 200 m. The need for this columnar profiling arises from ...

  2. Mechanics of interrill erosion with wind-driven rain

    Science.gov (United States)

    The vector physics of wind-driven rain (WDR) differs from that of wind-free rain, and the interrill soil detachment equations in the Water Erosion Prediction Project (WEPP) model were not originally developed to deal with this phenomenon. This article provides an evaluation of the performance of the...

  3. Determination of key parameters of vector multifractal vector fields

    Science.gov (United States)

    Schertzer, D. J. M.; Tchiguirinskaia, I.

    2017-12-01

    For too long time, multifractal analyses and simulations have been restricted to scalar-valued fields (Schertzer and Tchiguirinskaia, 2017a,b). For instance, the wind velocity multifractality has been mostly analysed in terms of scalar structure functions and with the scalar energy flux. This restriction has had the unfortunate consequences that multifractals were applicable to their full extent in geophysics, whereas it has inspired them. Indeed a key question in geophysics is the complexity of the interactions between various fields or they components. Nevertheless, sophisticated methods have been developed to determine the key parameters of scalar valued fields. In this communication, we first present the vector extensions of the universal multifractal analysis techniques to multifractals whose generator belong to a Levy-Clifford algebra (Schertzer and Tchiguirinskaia, 2015). We point out further extensions noting the increased complexity. For instance, the (scalar) index of multifractality becomes a matrice. Schertzer, D. and Tchiguirinskaia, I. (2015) `Multifractal vector fields and stochastic Clifford algebra', Chaos: An Interdisciplinary Journal of Nonlinear Science, 25(12), p. 123127. doi: 10.1063/1.4937364. Schertzer, D. and Tchiguirinskaia, I. (2017) `An Introduction to Multifractals and Scale Symmetry Groups', in Ghanbarian, B. and Hunt, A. (eds) Fractals: Concepts and Applications in Geosciences. CRC Press, p. (in press). Schertzer, D. and Tchiguirinskaia, I. (2017b) `Pandora Box of Multifractals: Barely Open ?', in Tsonis, A. A. (ed.) 30 Years of Nonlinear Dynamics in Geophysics. Berlin: Springer, p. (in press).

  4. WIND TURBINES FOR WIND POWER INSTALLATIONS

    Directory of Open Access Journals (Sweden)

    Barladean A.S.

    2008-04-01

    Full Text Available The problem of wind turbine choice for wind power stations is examined in this paper. It is shown by comparison of parameters and characteristics of wind turbines, that for existing modes and speeds of wind in territory of Republic of Moldova it is necessary to use multi-blade small speed rotation wind turbines of fan class.

  5. Temporal Courses in EEG Theta and Alpha Activity in the Dynamic Health Qigong Techniques Wu Qin Xi and Liu Zi Jue

    Directory of Open Access Journals (Sweden)

    Diana Henz

    2018-01-01

    Full Text Available Health Qigong is a common technique of Traditional Chinese Medicine applied to strengthen mental and physical health. Several studies report increases in EEG theta and alpha activity after meditative Qigong techniques indicating a relaxed state of mind. To date, little is known on the effects of dynamic Health Qigong techniques that comprise bodily movements on brain activity. In the current study, we compared effects of two dynamic Health Qigong techniques on EEG brain activity. Subjects performed the techniques Wu Qin Xi (five animals play and Liu Zi Jue (six healing sounds in a within-subjects design. Eyes-open and eyes-closed resting EEG was recorded before and immediately after each 15-min practice block. Additionally, the Profile of Mood States (POMS questionnaire was administered at pretest, and after each 15-min practice block. Results show a decrease in alpha activity after 15 min, followed by an increase after 30 min in the Health Qigong technique Liu Zi Jue. Theta activity was decreased after 15 min, followed by an increase after 30 min in the technique Wu Qin Xi. Results of the POMS indicated an increased vigor-activity level with decreased fatigue and tension-anxiety levels in both techniques after 30 min of practice. Our results demonstrate different temporal dynamics in EEG theta and alpha activity for the Health Qigong techniques Wu Qin Xi and Liu Zi Jue. We hypothesize that the found brain activation patterns result from different attentional focusing styles and breathing techniques performed during the investigated Health Qigong techniques.

  6. Wind turbine

    Science.gov (United States)

    Cheney, Jr., Marvin C.

    1982-01-01

    A wind turbine of the type having an airfoil blade (15) mounted on a flexible beam (20) and a pitch governor (55) which selectively, torsionally twists the flexible beam in response to wind turbine speed thereby setting blade pitch, is provided with a limiter (85) which restricts unwanted pitch change at operating speeds due to torsional creep of the flexible beam. The limiter allows twisting of the beam by the governor under excessive wind velocity conditions to orient the blades in stall pitch positions, thereby preventing overspeed operation of the turbine. In the preferred embodiment, the pitch governor comprises a pendulum (65,70) which responds to changing rotor speed by pivotal movement, the limiter comprising a resilient member (90) which engages an end of the pendulum to restrict further movement thereof, and in turn restrict beam creep and unwanted blade pitch misadjustment.

  7. Coevolution of dependency distance, hierarchical structure and word order. Comment on "Dependency distance: a new perspective on syntactic patterns in natural languages" by Haitao Liu et al.

    Science.gov (United States)

    Jing, Yingqi

    2017-07-01

    Exploring the relationships between structural rules and their linearization constraints have been a central issue in formal syntax and linguistic typology [1]. Liu et al. give a historical overview of the investigation of dependency distance minimization (DDM) in various fields, and specify its potential connections with the graphic patterns of syntactic structure and the linear ordering of words and constituents in real sentences [2]. This comment focuses on discussing the relations between dependency distance (DD), hierarchical structure and word order, and advocates further study on the coevolution of these traits in language histories.

  8. On the relation between dependency distance, crossing dependencies, and parsing. Comment on "Dependency distance: a new perspective on syntactic patterns in natural languages" by Haitao Liu et al.

    Science.gov (United States)

    Gómez-Rodríguez, Carlos

    2017-07-01

    Liu et al. [1] provide a comprehensive account of research on dependency distance in human languages. While the article is a very rich and useful report on this complex subject, here I will expand on a few specific issues where research in computational linguistics (specifically natural language processing) can inform DDM research, and vice versa. These aspects have not been explored much in [1] or elsewhere, probably due to the little overlap between both research communities, but they may provide interesting insights for improving our understanding of the evolution of human languages, the mechanisms by which the brain processes and understands language, and the construction of effective computer systems to achieve this goal.

  9. Projectivity is the mathematical code of syntax. Comment on "Dependency distance: A new perspective on syntactic patterns in natural languages" by Haitao Liu et al.

    Science.gov (United States)

    Ninio, Anat

    2017-07-01

    The thought-provoking proposal by Liu, Xu and Liang [1] to integrate cognitive considerations involved in Dependency distance minimization (DDM) in syntactic theory will, I am sure, be much discussed in the literature. The authors are to be congratulated for a most serious, thorough and mature presentation. I am sure that DDM will find its rightful place alongside other cognitive factors that are considered to significantly affect the structure and evolution of language such as frequency with its serious impact on grammaticalization [2].

  10. Dependency distance in language evolution. Comment on "Dependency distance: A new perspective on syntactic patterns in natural languages" by Haitao Liu et al.

    Science.gov (United States)

    Liu, Bingli; Chen, Xinying

    2017-07-01

    In the target article [1], Liu et al. provide an informative introduction to the dependency distance studies and proclaim that language syntactic patterns, that relate to the dependency distance, are associated with human cognitive mechanisms, such as limited working memory and syntax processing. Therefore, such syntactic patterns are probably 'human-driven' language universals. Sufficient evidence based on big data analysis is also given in the article for supporting this idea. The hypotheses generally seem very convincing yet still need further tests from various perspectives. Diachronic linguistic study based on authentic language data, on our opinion, can be one of those 'further tests'.

  11. Southern hemisphere low level wind circulation statisticsfrom the Seasat scatterometer

    OpenAIRE

    G. Levy

    1994-01-01

    Analyses of remotely sensed low-level wind vector data over the Southern Ocean are performed. Five-day averages and monthly means are created and the month-to-month variability during the winter (July-September) of 1978 is investigated. The remotely sensed winds are compared to the Australian Bureau of Meteorology (ABM) and the National Meteorological Center (NMC) surface analyses. In southern latitudes the remotely sensed winds are stronger than what the weather services' analyses sugge...

  12. Supergravity inspired vector curvaton

    International Nuclear Information System (INIS)

    Dimopoulos, Konstantinos

    2007-01-01

    It is investigated whether a massive Abelian vector field, whose gauge kinetic function is growing during inflation, can be responsible for the generation of the curvature perturbation in the Universe. Particle production is studied and it is shown that the vector field can obtain a scale-invariant superhorizon spectrum of perturbations with a reasonable choice of kinetic function. After inflation the vector field begins coherent oscillations, during which it corresponds to pressureless isotropic matter. When the vector field dominates the Universe, its perturbations give rise to the observed curvature perturbation following the curvaton scenario. It is found that this is possible if, after the end of inflation, the mass of the vector field increases at a phase transition at temperature of order 1 TeV or lower. Inhomogeneous reheating, whereby the vector field modulates the decay rate of the inflaton, is also studied

  13. Measuring tropospheric wind with microwave sounders

    Science.gov (United States)

    Lambrigtsen, B.; Su, H.; Turk, J.; Hristova-Veleva, S. M.; Dang, V. T.

    2017-12-01

    In its 2007 "Decadal Survey" of earth science missions for NASA the U.S. National Research Council recommended that a Doppler wind lidar be developed for a three-dimensional tropospheric winds mission ("3D-Winds"). The technology required for such a mission has not yet been developed, and it is expected that the next Decadal Survey, planned to be released by the end of 2017, will put additional emphasis on the still pressing need for wind measurements from space. The first Decadal Survey also called for a geostationary microwave sounder (GMS) on a Precipitation and All-weather Temperature and Humidity (PATH) mission, which could be used to measure wind from space. Such a sounder, the Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR), has been developed at the Jet Propulsion Laboratory (JPL). The PATH mission has not yet been funded by NASA, but a low-cost subset of PATH, GeoStorm has been proposed as a hosted payload on a commercial communications satellite. Both PATH and GeoStorm would obtain frequent (every 15 minutes of better) measurements of tropospheric water vapor profiles, and they can be used to derive atmospheric motion vector (AMV) wind profiles, even in the presence of clouds. Measurement of wind is particularly important in the tropics, where the atmosphere is largely not in thermal balance and wind estimates cannot generally be derived from temperature and pressure fields. We report on simulation studies of AMV wind vectors derived from a GMS and from a cluster of low-earth-orbiting (LEO) small satellites (e.g., CubeSats). The results of two separate simulation studies are very encouraging and show that a ±2 m/s wind speed precision is attainable, which would satisfy WMO requirements. A GMS observing system in particular, which can be implemented now, would enable significant progress in the study of atmospheric dynamics. Copyright 2017 California Institute of Technology. Government sponsorship acknowledged

  14. Orthogonalisation of Vectors

    Indian Academy of Sciences (India)

    The vectors aI, a2 are lin- early independent and each of them has norm 1. How- ever, they are not orthogonal to each other. The Gram-. Schmidt process applied to them gives the vectors ql == (1,0), q2 = (0,1). The distance between the pair {all a2} and the pair {q I' q2} is (t) ~. Can we find another pair of orthonormal vectors ...

  15. Doppler Lidar for Wind Measurements on Venus

    Science.gov (United States)

    Singh, Upendra N.; Emmitt, George D.; Yu, Jirong; Kavaya, Michael J.

    2010-01-01

    NASA Langley Research Center has a long history of developing 2-micron laser transmitter for wind sensing. With support from NASA Laser Risk Reduction Program (LRRP) and Instrument Incubator Program (IIP), NASA Langley Research Center has developed a state-of-the-art compact lidar transceiver for a pulsed coherent Doppler lidar system for wind measurement. The transmitter portion of the transceiver employs the high-pulse-energy, Ho:Tm:LuLiF, partially conductively cooled laser technology developed at NASA Langley. The transceiver is capable of 250 mJ pulses at 10 Hz. It is very similar to the technology envisioned for coherent Doppler lidar wind measurements from Earth and Mars orbit. The transceiver is coupled to the large optics and data acquisition system in the NASA Langley VALIDAR mobile trailer. The large optics consists of a 15-cm off-axis beam expanding telescope, and a full-hemispheric scanner. Vertical and horizontal vector winds are measured, as well as relative backscatter. The data acquisition system employs frequency domain velocity estimation and pulse accumulation. It permits real-time display of the processed winds and archival of all data. This lidar system was recently deployed at Howard University facility in Beltsville, Mary-land, along with other wind lidar systems. Coherent Doppler wind lidar ground-based wind measurements and comparisons with other sensors will be presented. A simulation and data product for wind measurement at Venus will be presented.

  16. Wind power

    International Nuclear Information System (INIS)

    2006-06-01

    This road-map proposes by the Group Total aims to inform the public on the wind power. It presents the principles, the technology takes off, its applications and technology focus, the global market trends and the outlooks and Total commitments in the domain. (A.L.B.)

  17. Wind energy

    International Nuclear Information System (INIS)

    Portilla S, L.A.

    1995-01-01

    The wind energy or eolic energy is a consequence of solar energy, the one which is absorbed by the atmosphere and is transformed into energy of movement of large bulks of air. In this process the atmosphere acts as the filter to the solar radiation and demotes the ultraviolet beams that result fatal to life in the Earth. The ionosphere is the most external cap and this is ionized by means of absorption process of ultraviolet radiation arising to the Sun. The atmosphere also acts as a trap to the infrared radiation, it that results from the continual process of energetic degradation. In this way, the interaction between Earth - Atmospheres, is behaved as a great greenhouse, maintaining the constant temperatures, including in the dark nights. Processes as the natural convection (that occur by the thermodynamic phenomenon), equatorial calmness, trade winds and against trade winds and global distribution of the air currents are described. The other hand, techniques as the transformation of the wind into energy and its parameters also are shown

  18. Vectors and their applications

    CERN Document Server

    Pettofrezzo, Anthony J

    2005-01-01

    Geared toward undergraduate students, this text illustrates the use of vectors as a mathematical tool in plane synthetic geometry, plane and spherical trigonometry, and analytic geometry of two- and three-dimensional space. Its rigorous development includes a complete treatment of the algebra of vectors in the first two chapters.Among the text's outstanding features are numbered definitions and theorems in the development of vector algebra, which appear in italics for easy reference. Most of the theorems include proofs, and coordinate position vectors receive an in-depth treatment. Key concept

  19. Wind Energy Japan

    Energy Technology Data Exchange (ETDEWEB)

    Komatsubara, Kazuyo [Embassy of the Kingdom of the Netherlands, Tokyo (Japan)

    2012-06-15

    An overview is given of wind energy in Japan: Background; Wind Energy in Japan; Japanese Wind Energy Industry; Government Supports; Useful Links; Major Japanese Companies; Profiles of Major Japanese Companies; Major Wind Energy Projects in Japan.

  20. Bluetongue vector species of Culicoides in Switzerland.

    Science.gov (United States)

    Cagienard, A; Griot, C; Mellor, P S; Denison, E; Stärk, K D C

    2006-06-01

    Switzerland is historically recognized by the Office Internationale des Epizooties as free from bluetongue disease (BT) because of its latitude and climate. With bluetongue virus (BTV) moving north from the Mediterranean, an entomological survey was conducted in Switzerland in 2003 to assess the potential of the BTV vectors present. A total of 39 cattle farms located in three geographical regions, the Ticino region, the Western region and the region of the Grisons, were monitored during the vector season. Farms were located in areas at high risk of vector introduction and establishment based on the following characteristics: annual average temperature > 12.5 degrees C, average annual humidity >or= 60%, cattle farm. Onderstepoort black light traps were operated at the cattle farms generally for one night in July and one night in September. A total of 56 collections of Culicoides (Diptera: Ceratopogonidae) were identified morphologically. Only one single individual of Culicoides (Avaritia) imicola, the major Old World vector of BTV, was found in July 2003 in the Ticino region, one of the southernmost regions of Switzerland. In the absence of further specimens of C. imicola from Switzerland it is suggested that this individual may be a vagrant transported by wind from regions to the south of the country where populations of this species are known to occur. Alternative potential BTV vectors of the Culicoides (Culicoides) pulicaris and Culicoides (Avaritia) obsoletus complexes were abundant in all sampled regions with individual catches exceeding 70 000 midges per trap night.

  1. Study of wind change for the development of loads reduction techniques for the space shuttle

    Science.gov (United States)

    Adelfang, S. I.

    1987-01-01

    Wind change statistics are analyzed for Vandenberg AFB, California (VAFB) and Kennedy Space Center, Florida (KSC). Means and standard deviations of wind component change and vector wind change modulus within 3-9 and 9-16 km altitude bands are tabulated. The contribution to 3.5 hr wind component change by wind perturbations in various wavelength bands is evaluated. Probability distributions of maximum 3.5 hr wind change in an altitude band are presented and a model for wind change at a specified altitude is tested with data derived from six data bases from VAFB and Santa Monica, California.

  2. Feasibility Study of the PS Injection for 2 GeV LIU Beams with an Upgraded KFA-45 Injection Kicker System Operating in Short Circuit Mode

    CERN Document Server

    Kramer, Thomas; Borburgh, Jan; Ducimetière, Laurent; Feliciano, Luis; Ferrero Colomo, Alvaro; Goddard, Brennan; Sermeus, Luc

    2016-01-01

    Under the scope of the LIU project the CERN PS Booster to PS beam transfer will be modified to match the requirements for the future 2 GeV beams. This paper describes the evaluation of the proposed upgrade of the PS injection kicker. Different schemes of an injection for LIU beams into the PS have been outlined in the past already under the aspect of individual transfer kicker rise and fall time performances. Homogeneous rise and fall time requirements in the whole PSB to PS transfer chain have been established which allowed to consider an upgrade option of the present injection kicker system operated in short circuit mode. The challenging pulse quality constraints require an improvement of the flat top and post pulse ripples. Both operation modes, terminated and short circuit mode are analysed and analogue circuit simulations for the present and upgraded system are outlined. Recent measurements on the installed kickers are presented and analysed together with the simulation data. First measurements verifying...

  3. Multivariable Wind Modeling in State Space

    DEFF Research Database (Denmark)

    Sichani, Mahdi Teimouri; Pedersen, B. J.

    2011-01-01

    -spectral density matrix a frequency response matrix is constructed which determines the turbulence vector as a linear filtration of Gaussian white noise. Finally, an accurate state space modeling method is proposed which allows selection of an appropriate model order, and estimation of a state space model......Turbulence of the incoming wind field is of paramount importance to the dynamic response of wind turbines. Hence reliable stochastic models of the turbulence should be available from which time series can be generated for dynamic response and structural safety analysis. In the paper an empirical...... cross-spectral density function for the along-wind turbulence component over the rotor plane is taken as the starting point. The spectrum is spatially discretized in terms of a Hermitian cross-spectral density matrix for the turbulence state vector which turns out not to be positive definite. Since...

  4. CHROMASSI: a therapy advice system based on chrono-massage and acupression using the method of ZiWuLiuZhu.

    Science.gov (United States)

    Nguyen, H P; Le, D L; Tran, Q M; Nguyen, V T; Nguyen, N O

    1995-01-01

    Massage and Acupression have a history of many years of use by the Vietnamese people in the treatment of diseases, and they can give wonderful therapeutic effects in painful syndromes and chronic diseases, etc. On the other hand, some methods of Chrono-Acupuncture based on chronobiological theory and the holistic concept of traditional medicine are studied and applied in clinical applications. This paper presents the therapy advice system based on Chrono-Massage and Acupression using the method of ZiWuLiuZhu called CHROMASSI. The system includes four major parts. Massage and Acupression Teaching: This part can provide the user with some background in Massage and Acupression theory such as the pathology of the meridians, the classification of points and their function, the therapeutic properties of points, the methods of Massage and Acupression (including Pression, Friction, Rubbing, Light Massage, Petrissage, Rolling and Rubbing, Percussion and Vibration), and the direction of the meridians circulation, displaying AcuPoints represented by color pictures of the 12 main meridians and 2 vessels. More than 330 popular AcuPoints are used in the system. Open AcuPoint Calculating: This module can help us to calculate open AcuPoints based on data about days, months, years and hours using the special method of ZiWuLiuZhu. The Points adopted by ZiWuLiuZhu are the Five Shu Points and Source Points including 66 points (all of them are located below the elbows and knees). The effectiveness of these points becomes particularly evident when they are needled or punctured at optimum time intervals. For example, at 9:00 a.m., September 22, 1994, the open Points by the ZiWuLiuZhu method will be the points K2 (Nhien Coc) and K10 (Am Coc). According to the chronotherapeutic method, first we have to pressure (or puncture) the above points in order to attain the sensation RDac KhiS (arrival of energy), then pressure the other treating points as in ordinary Massage and Acupression

  5. Wind Loads on Structures

    DEFF Research Database (Denmark)

    Dyrbye, Claes; Hansen, Svend Ole

    Wind loads have to be taken into account when designing civil engineering structures. The wind load on structures can be systematised by means of the wind load chain: wind climate (global), terrain (wind at low height), aerodynamic response (wind load to pressure), mechanical response (wind...... pressure to structural response) and design criteria. Starting with an introduction of the wind load chain, the book moves on to meteorological considerations, atmospheric boundary layer, static wind load, dynamic wind load and scaling laws used in wind-tunnel tests. The dynamic wind load covers vibrations...... induced by wind turbulence, vortex shedding, flutter and galloping. The book gives a comprehensive treatment of wind effects on structures and it will be useful for consulting engineers designing wind-sensitive structures. It will also be valuable for students of civil engineering as textbook...

  6. Vector-Vector Scattering on the Lattice

    Science.gov (United States)

    Romero-López, Fernando; Urbach, Carsten; Rusetsky, Akaki

    2018-03-01

    In this work we present an extension of the LüScher formalism to include the interaction of particles with spin, focusing on the scattering of two vector particles. The derived formalism will be applied to Scalar QED in the Higgs Phase, where the U(1) gauge boson acquires mass.

  7. De Vector wetenschappelijk bekeken

    NARCIS (Netherlands)

    Slot, D.E.; van der Weijden, F.

    2009-01-01

    In juni 2008 heeft de sectie Parodontologie van ACTA een systematische review gepubliceerd over het effect van de Vector®. De vraagstelling luidde: Wat is het effect van het gebruik van de Vector® op (menselijke) gebitselementen vergeleken met ultrasone apparatuur of handinstrumentarium op

  8. Brane vector phenomenology

    International Nuclear Information System (INIS)

    Clark, T.E.; Love, S.T.; Nitta, Muneto; Veldhuis, T. ter; Xiong, C.

    2009-01-01

    Local oscillations of the brane world are manifested as massive vector fields. Their coupling to the Standard Model can be obtained using the method of nonlinear realizations of the spontaneously broken higher-dimensional space-time symmetries, and to an extent, are model independent. Phenomenological limits on these vector field parameters are obtained using LEP collider data and dark matter constraints

  9. Advancing vector biology research

    NARCIS (Netherlands)

    Kohl, Alain; Pondeville, Emilie; Schnettler, Esther; Crisanti, Andrea; Supparo, Clelia; Christophides, George K.; Kersey, Paul J.; Maslen, Gareth L.; Takken, Willem; Koenraadt, Constantianus J.M.; Oliva, Clelia F.; Busquets, Núria; Abad, F.X.; Failloux, Anna Bella; Levashina, Elena A.; Wilson, Anthony J.; Veronesi, Eva; Pichard, Maëlle; Arnaud Marsh, Sarah; Simard, Frédéric; Vernick, Kenneth D.

    2016-01-01

    Vector-borne pathogens impact public health, animal production, and animal welfare. Research on arthropod vectors such as mosquitoes, ticks, sandflies, and midges which transmit pathogens to humans and economically important animals is crucial for development of new control measures that target

  10. Vector mesons in matter

    Indian Academy of Sciences (India)

    One consequence of the chiral restoration is the mixing of parity partners. We look for a possible signature of the mixing of vector and axial vector mesons in heavy-ion collisions. We suggest an experimental method for its observation. The dynamical evolution of the heavy-ion collision is described by a transport equation of ...

  11. Architecture and Vector Control

    DEFF Research Database (Denmark)

    von Seidlein, Lorenz; Knols, Bart GJ; Kirby, Matthew

    2012-01-01

    The character of buildings plays a major role in disease control. It is understood that water supply and sanitation are critical for the well-being of residents. Current vector control programs aim to prevent the access of vector to the human host. This can be achieved through screened windows, c...

  12. Complex Polynomial Vector Fields

    DEFF Research Database (Denmark)

    Dias, Kealey

    The two branches of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions...... or meromorphic (allowing poles as singularities) functions. There already exists a well-developed theory for iterative holomorphic dynamical systems, and successful relations found between iteration theory and flows of vector fields have been one of the main motivations for the recent interest in holomorphic...... vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...

  13. Complex Polynomial Vector Fields

    DEFF Research Database (Denmark)

    vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...... of parameter spaces into structurally stable domains, and a description of the bifurcations. For this reason, the talk will focus on these questions for complex polynomial vector fields.......The two branches of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions...

  14. Stellar winds

    International Nuclear Information System (INIS)

    Weymann, R.J.

    1978-01-01

    It is known that a steady outflow of material at comparable rates of mass loss but vastly different speeds is now known to be ubiquitous phenomenon among both the luminous hot stars and the luminous but cool red giants. The flows are probably massive enough in both cases to give rise to significant effects on stellar evolution and the mass balance between stars and the interstellar medium. The possible mechanisms for these phenomena as well as the methods of observation used are described. In particular, the mass-loss processes in stars other than the sun that also involve a steady flow of matter are considered. The evidence for their existence is described, and then the question of whether the process thought to produce the solar wind is also responsible for producing these stellar winds is explored

  15. CubeSat Constellation Cloud Winds(C3Winds) A New Wind Observing System to Study Mesoscale Cloud Dynamics and Processes

    Science.gov (United States)

    Wu, D. L.; Kelly, M.A.; Yee, J.-H.; Boldt, J.; Demajistre, R.; Reynolds, E. L.; Tripoli, G. J.; Oman, L. D.; Prive, N.; Heidinger, A. K.; hide

    2016-01-01

    The CubeSat Constellation Cloud Winds (C3Winds) is a NASA Earth Venture Instrument (EV-I) concept with the primary objective to better understand mesoscale dynamics and their structures in severe weather systems. With potential catastrophic damage and loss of life, strong extratropical and tropical cyclones (ETCs and TCs) have profound three-dimensional impacts on the atmospheric dynamic and thermodynamic structures, producing complex cloud precipitation patterns, strong low-level winds, extensive tropopause folds, and intense stratosphere-troposphere exchange. Employing a compact, stereo IR-visible imaging technique from two formation-flying CubeSats, C3Winds seeks to measure and map high-resolution (2 km) cloud motion vectors (CMVs) and cloud geometric height (CGH) accurately by tracking cloud features within 5-15 min. Complementary to lidar wind observations from space, the high-resolution wind fields from C3Winds will allow detailed investigations on strong low-level wind formation in an occluded ETC development, structural variations of TC inner-core rotation, and impacts of tropopause folding events on tropospheric ozone and air quality. Together with scatterometer ocean surface winds, C3Winds will provide a more comprehensive depiction of atmosphere-boundary-layer dynamics and interactive processes. Built upon mature imaging technologies and long history of stereoscopic remote sensing, C3Winds provides an innovative, cost-effective solution to global wind observations with potential of increased diurnal sampling via CubeSat constellation.

  16. Wind conditions for wind turbine design

    Energy Technology Data Exchange (ETDEWEB)

    Maribo Pedersen, B.

    1999-04-01

    Delegates from Europe and USA attended the meeting and discussed general aspects of wind conditions for wind turbine design. The subjects and the presented papers covered a very broad range of aspects of wind conditions and related influence on the wind turbine. (EHS)

  17. Revisiting the vector and axial-vector vacuum susceptibilities

    International Nuclear Information System (INIS)

    Chang Lei; Liu Yuxin; Sun Weimin; Zong Hongshi

    2008-01-01

    We re-investigate the vector and axial-vector vacuum susceptibilities by taking advantage of the vector and axial-vector Ward-Takahashi identities. We show analytically that, in the chiral limit, the vector vacuum susceptibility is zero and the axial-vector vacuum susceptibility equals three fourths of the square of the pion decay constant. Besides, our analysis reproduces the Weinberg sum rule

  18. SSMI Wind Speed Climatology of the Time of Monsoon Wind Offset in the Western Arabian Sea

    Science.gov (United States)

    Halpern, David

    2000-01-01

    Forecasting the time of onset of monsoon wind in the western Arabian Sea, which is believed to precede the onset of rainfall along the west coast of India, is an important unsolved problem. Prior to measurements of the surface wind field by satellite, there was an absence of suitable surface wind observations. NASA scatterometer (NSCAT) surface wind vectors revealed that the time of the 1997 onset of 12 m/s southwest monsoon wind speeds in the western Arabian Sea preceded the onset of monsoon rainfall in Goa, India, by 3 - 4 days. Wind speed and direction data were necessary to establish a dynamical mechanism between times of onset of 12 m/s wind speed off Somalia and rainfall in Goa. Except for NSCAT, no satellite scatterometer wind product recorded adequately sampled 2-day 1deg x 1deg averaged wind vectors, which are the required space and time scales, to examine the wind-rain relationship in other years. However, the greater-than-95% steadiness of summer monsoon winds allows an opportunity to use satellite measurements of surface wind speed. The Special Sensor Microwave Imager (SSMI) recorded surface wind speed with adequate sampling to produce a 1-day, 1deg x 1deg data product during 1988 - 1998. SSMI data had been uniformly processed throughout the period. Times of onset of 12 m/s wind speed off Somalia determined with the SSMI data set were 21 May 1988, 24 May 1989, 17 May 1990, 28 May 1991, 8 June 1992, 28 May 1993, 30 May 1994, 7 June 1995, 29 May 1996, 12 June 1997, and 15 May 1998. Uncertainty of the 1992 and 1996 times of onset were increased because of the absence of SSMI data on 6 and 7 June 1992 and on 30 May 1996. Correlations of timing of monsoon wind onset with El Nino will be described. Variability of the time difference between times of onset of 12 m/s wind speed and Goa rainfall will be discussed. At the time of submission of the abstract, the Goa rainfall data have not arrived from the India Meteorological Department.

  19. Wind Technologies & Evolving Opportunities (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Robichaud, R.

    2014-07-01

    This presentation covers opportunities for wind technology; wind energy market trends; an overview of the National Wind Technology Center near Boulder, Colorado; wind energy price and cost trends; wind turbine technology improvements; and wind resource characterization improvements.

  20. Computer simulation as an important approach to explore language universal. Comment on "Dependency distance: a new perspective on syntactic patterns in natural languages" by Haitao Liu et al.

    Science.gov (United States)

    Lu, Qian

    2017-07-01

    Exploring language universal is one of the major goals of linguistic researches, which are largely devoted to answering the ;Platonic questions; in linguistics, that is, what is the language knowledge, how to get and use this knowledge. However, if solely guided by linguistic intuition, it is very difficult for syntactic studies to answer these questions, or to achieve abstractions in the scientific sense. This suggests that linguistic analyses based on the probability theory may provide effective ways to investigate into language universals in terms of biological motivations or cognitive psychological mechanisms. With the view that ;Language is a human-driven system;, Liu, Xu & Liang's review [1] pointed out that dependency distance minimization (DDM), which has been corroborated by big data analysis of corpus, may be a language universal shaped in language evolution, a universal that has profound effect on syntactic patterns.

  1. Retraction: 'Imaging characteristics of liver Langerhans cell histiocytosis in children' by Hui Liu, Xueying Long, Xiaoyi Wang, Wenzheng Li and Yigang Pei.

    Science.gov (United States)

    2017-09-01

    The above article from Pediatrics International, published as an Accepted Article online on April 28, 2017 in Wiley Online Library (http://wileyonlinelibrary.com) has been withdrawn by agreement between the authors, the Journal Editor-in-Chief, Atsushi Manabe, and John Wiley & Sons Australia, Ltd, on behalf of the Japan Pediatric Society. The withdrawal has been agreed at the request of the authors who have identified some serious problems that need to be addressed and who have found that some important information is missing. 1 Liu, H., Long, X., Wang, X., Li W. and Pei, Y. (2017), Imaging characteristics of liver Langerhans cell histiocytosis in children. Pediatrics International. Doi 10.1111/ped.13313. © 2017 Japan Pediatric Society.

  2. [An exploration of the training of medical talents in China for Ryukyu islands based on the Liu qiu bai wen (One Hundred Question of Ryukyu)].

    Science.gov (United States)

    He, Lanping

    2014-09-01

    Ryukyu sent more than 20 batches of returned students to China for studying during the Ming and Qing Dynasties, many of whom were studying medicine. Liu qiu bai wen (One Hundred Question of Ryukyu) was the record of discussion between Cao Cunxin, a famous doctor of the Qing Dynasty, and the oversea disciples of Lü Fengyi from Ryukyu. However, it was not only a medical book, but also served as an important witness on overseas dissemination of TCM, and the fresh case of Chinese training medical talented persons for Ryukyu. Training Ryukyu medical students in the Qing Dynasty was good for the expansion of Chinese medicine in the Ryukyu, and promoted the development and social progress of the Ryukyu medicine and health, made a significant contribution to maintain the friendly relationship between the two countries.

  3. Dependency distance minimization in understanding of ambiguous structure. Comment on "Dependency distance: A new perspective on syntactic patterns in natural languages" by Haitao Liu et al.

    Science.gov (United States)

    Zhao, Yiyi

    2017-07-01

    Dependency Distance, proposed by Hudson [1], calculated by Liu [2,3], is an important concept in Dependency Theory. It can be used as a measure of the syntactic difficulty, and lots of research [2,4] have testified the universal of Dependency Distance in various languages. Human languages seem to present a preference for short dependency distance, which may be explained in terms of general cognitive constraint of limited working memory [5]. Psychological experiments in English, German, Russian and Chinese support the hypothesis that Dependency Distance minimization (DDM) make languages to evolve into some syntactic patterns to reduce memory burden [6-9]. The study of psychology focuses on the process and mechanism of syntactic structure selection in speech comprehension. In many speech comprehension experiments [10], ambiguous structure is an important experimental material.

  4. Spatio-temporal data analytics for wind energy integration

    CERN Document Server

    Yang, Lei; Zhang, Junshan

    2014-01-01

    This SpringerBrief presents spatio-temporal data analytics for wind energy integration using stochastic modeling and optimization methods. It explores techniques for efficiently integrating renewable energy generation into bulk power grids. The operational challenges of wind, and its variability are carefully examined. A spatio-temporal analysis approach enables the authors to develop Markov-chain-based short-term forecasts of wind farm power generation. To deal with the wind ramp dynamics, a support vector machine enhanced Markov model is introduced. The stochastic optimization of economic di

  5. Wind Power Meteorology

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik; Mortensen, Niels Gylling; Landberg, Lars

    Wind power meteorology has evolved as an applied science, firmly founded on boundary-layer meteorology, but with strong links to climatology and geography. It concerns itself with three main areas: siting of wind turbines, regional wind resource assessment, and short-term prediction of the wind...... resource. The history, status and perspectives of wind power meteorology are presented, with emphasis on physical considerations and on its practical application. Following a global view of the wind resource, the elements of boundary layer meteorology which are most important for wind energy are reviewed......: wind profiles and shear, turbulence and gust, and extreme winds. The data used in wind power meteorology stem mainly from three sources: onsite wind measurements, the synoptic networks, and the re-analysis projects. Wind climate analysis, wind resource estimation and siting further require a detailed...

  6. 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.

  7. Noncausal Bayesian Vector Autoregression

    DEFF Research Database (Denmark)

    Lanne, Markku; Luoto, Jani

    We propose a Bayesian inferential procedure for the noncausal vector autoregressive (VAR) model that is capable of capturing nonlinearities and incorporating effects of missing variables. In particular, we devise a fast and reliable posterior simulator that yields the predictive distribution...

  8. Tagged Vector Contour (TVC)

    Data.gov (United States)

    Kansas Data Access and Support Center — The Kansas Tagged Vector Contour (TVC) dataset consists of digitized contours from the 7.5 minute topographic quadrangle maps. Coverage for the state is incomplete....

  9. Vector hysteresis models

    Czech Academy of Sciences Publication Activity Database

    Krejčí, Pavel

    1991-01-01

    Roč. 2, - (1991), s. 281-292 ISSN 0956-7925 Keywords : vector hysteresis operator * hysteresis potential * differential inequality Subject RIV: BA - General Mathematics http://www.math.cas.cz/~krejci/b15p.pdf

  10. Prospecting for Wind

    Science.gov (United States)

    Swapp, Andy; Schreuders, Paul; Reeve, Edward

    2011-01-01

    Many people use wind to help meet their needs. Over the years, people have been able to harness or capture the wind in many different ways. More recently, people have seen the rebirth of electricity-generating wind turbines. Thus, the age-old argument about technology being either good or bad can also be applied to the wind. The wind can be a…

  11. Careers in Wind Energy

    Science.gov (United States)

    Liming, Drew; Hamilton, James

    2011-01-01

    As a common form of renewable energy, wind power is generating more than just electricity. It is increasingly generating jobs for workers in many different occupations. Many workers are employed on wind farms: areas where groups of wind turbines produce electricity from wind power. Wind farms are frequently located in the midwestern, western, and…

  12. Support vector machines applications

    CERN Document Server

    Guo, Guodong

    2014-01-01

    Support vector machines (SVM) have both a solid mathematical background and good performance in practical applications. This book focuses on the recent advances and applications of the SVM in different areas, such as image processing, medical practice, computer vision, pattern recognition, machine learning, applied statistics, business intelligence, and artificial intelligence. The aim of this book is to create a comprehensive source on support vector machine applications, especially some recent advances.

  13. Vector financial rogue waves

    International Nuclear Information System (INIS)

    Yan, Zhenya

    2011-01-01

    The coupled nonlinear volatility and option pricing model presented recently by Ivancevic is investigated, which generates a leverage effect, i.e., stock volatility is (negatively) correlated to stock returns, and can be regarded as a coupled nonlinear wave alternative of the Black–Scholes option pricing model. In this Letter, we analytically propose vector financial rogue waves of the coupled nonlinear volatility and option pricing model without an embedded w-learning. Moreover, we exhibit their dynamical behaviors for chosen different parameters. The vector financial rogue wave (rogon) solutions may be used to describe the possible physical mechanisms for the rogue wave phenomena and to further excite the possibility of relative researches and potential applications of vector rogue waves in the financial markets and other related fields. -- Highlights: ► We investigate the coupled nonlinear volatility and option pricing model. ► We analytically present vector financial rogue waves. ► The vector financial rogue waves may be used to describe the extreme events in financial markets. ► This results may excite the relative researches and potential applications of vector rogue waves.

  14. Effect of Fu-Zheng-Xiao-Liu Granules on Expression of Human Epidermal Growth Factor Receptor 2 (HER-2) and Proliferation and Apoptosis of Breast Cancer Cell Line SKBR-3

    OpenAIRE

    Mo, Ting; Yue, Shuangbing; Tian, Huan; Lin, Hong; Zhang, Guanglu; Zhang, Zili

    2016-01-01

    Background Previous research showed that granulized Fu-Zheng-Xiao-Liu has a significant effect on breast cancer. However, it remains unclear whether HER-2 plays a role in this anti-cancer effect. Material/Methods Serum of male SD rats administered Fu-Zheng-Xiao-Liu granules (SF) was prepared and used to treat HER-2 positive breast cancer cell line SKBR-3. PBS and herceptin were used as negative and positive controls, respectively. MTT was used to detect the proliferation of SKBR-3 cells. Flow...

  15. Offshore wind climatology based on synergetic use of Envisat ASAR, ASCAT and QuikSCAT

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Mouche, Alexis; Badger, Merete

    2015-01-01

    The offshore wind climatology in the Northern European seas is analysed from ten years of Envisat synthetic aperture radar (SAR) images using a total of 9256 scenes, ten years of QuikSCAT and two years of ASCAT gridded ocean surface vector wind products and high-quality wind observations from four...... of such measurements is very high and therefore they are only sparsely available. An alternative method is the application of satellite remote sensing. Comparison of wind resource statistics from satellite products is presented and discussed including the uncertainty on the wind resource. The diurnal wind variability...

  16. Vectorization of nuclear codes for atmospheric transport and exposure calculation of radioactive materials

    International Nuclear Information System (INIS)

    Asai, Kiyoshi; Shinozawa, Naohisa; Ishikawa, Hirohiko; Chino, Masamichi; Hayashi, Takashi

    1983-02-01

    Three computer codes MATHEW, ADPIC of LLNL and GAMPUL of JAERI for prediction of wind field, concentration and external exposure rate of airborne radioactive materials are vectorized and the results are presented. Using the continuous equation of incompressible flow as a constraint, the MATHEW calculates the three dimensional wind field by a variational method. Using the particle-in -cell method, the ADPIC calculates the advection and diffusion of radioactive materials in three dimensional wind field and terrain, and gives the concentration of the materials in each cell of the domain. The GAMPUL calculates the external exposure rate assuming Gaussian plume type distribution of concentration. The vectorized code MATHEW attained 7.8 times speedup by a vector processor FACOM230-75 APU. The ADPIC and GAMPUL are estimated to attain 1.5 and 4 times speedup respectively on CRAY-1 type vector processor. (author)

  17. Influence of wind loading

    OpenAIRE

    MAVLONOV RAVSHANBEK ABDUJABBOROVICH; VAKKASOV KHAYRULLO SAYFULLAHANOVICH

    2015-01-01

    Each wind load is determined by a probabilistic-statistical method based on the concept of “equivalent static wind load”, on the assumption that structural frames and components/cladding behave elastically in strong wind.

  18. Tower Winds - Cape Kennedy

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Digitized data taken from Wind Gust Charts. Record contains hourly wind directions and speed with a peak wind recorded at the end of each day. Sorted by: station,...

  19. Wind energy program overview

    International Nuclear Information System (INIS)

    1992-02-01

    This overview emphasizes the amount of electric power that could be provided by wind power rather than traditional fossil fuels. New wind power markets, advances in technology, technology transfer, and wind resources are some topics covered in this publication

  20. Modeling and analysis of doubly fed induction generator wind energy systems

    CERN Document Server

    Fan, Lingling

    2015-01-01

    Wind Energy Systems: Modeling, Analysis and Control with DFIG provides key information on machine/converter modelling strategies based on space vectors, complex vector, and further frequency-domain variables. It includes applications that focus on wind energy grid integration, with analysis and control explanations with examples. For those working in the field of wind energy integration examining the potential risk of stability is key, this edition looks at how wind energy is modelled, what kind of control systems are adopted, how it interacts with the grid, as well as suitable study

  1. Modelling Wind for Wind Farm Layout Optimization Using Joint Distribution of Wind Speed and Wind Direction

    OpenAIRE

    Ju Feng; Wen Zhong Shen

    2015-01-01

    Reliable wind modelling is of crucial importance for wind farm development. The common practice of using sector-wise Weibull distributions has been found inappropriate for wind farm layout optimization. In this study, we propose a simple and easily implementable method to construct joint distributions of wind speed and wind direction, which is based on the parameters of sector-wise Weibull distributions and interpolations between direction sectors. It is applied to the wind measurement data a...

  2. Denmark Wind Energy Programme

    DEFF Research Database (Denmark)

    Shen, Wen Zhong

    2014-01-01

    In this paper, a summary of some ongoing wind energy projects in Denmark is given. The research topics comprise computational model development, wind turbine design, low noise airfoil and blade design, control device development, wake modelling, and wind farm layout optimization.......In this paper, a summary of some ongoing wind energy projects in Denmark is given. The research topics comprise computational model development, wind turbine design, low noise airfoil and blade design, control device development, wake modelling, and wind farm layout optimization....

  3. Superconducting Wind Turbine Generators

    OpenAIRE

    Yunying Pan; Danhzen Gu

    2016-01-01

    Wind energy is well known as a renewable energy because its clean and less polluted characteristic, which is the foundation of development modern wind electricity. To find more efficient wind turbine is the focus of scientists around the world. Compared from conventional wind turbines, superconducting wind turbine generators have advantages at zero resistance, smaller size and lighter weight. Superconducting wind turbine will inevitably become the main trends in this area. This paper intends ...

  4. Wind turbines, is it just wind?

    International Nuclear Information System (INIS)

    Boiteux, M.

    2012-01-01

    The author first outlines that wind energy is not only random, but almost absent in extreme situations when it would be needed (for example and notably, very cold weather without wind). He suggests the association of a gas turbine to each wind turbine, so that the gas turbine will replace non operating wind turbines. He notices that wind turbines are not proximity energy as they were said to be, and that profitability in fact requires tens of grouped giant wind turbines. He also outlines the high cost of construction of grids for the connection of these wind turbines. Thus, he states that wind energy is far from being profitable in the present conditions of electricity tariffs in France

  5. Advanced structural wind engineering

    CERN Document Server

    Kareem, Ahsan

    2013-01-01

    This book serves as a textbook for advanced courses as it introduces state-of-the-art information and the latest research results on diverse problems in the structural wind engineering field. The topics include wind climates, design wind speed estimation, bluff body aerodynamics and applications, wind-induced building responses, wind, gust factor approach, wind loads on components and cladding, debris impacts, wind loading codes and standards, computational tools and computational fluid dynamics techniques, habitability to building vibrations, damping in buildings, and suppression of wind-induced vibrations. Graduate students and expert engineers will find the book especially interesting and relevant to their research and work.

  6. Wind for Schools (Poster)

    Energy Technology Data Exchange (ETDEWEB)

    Baring-Gould, I.

    2010-05-01

    As the United States dramatically expands wind energy deployment, the industry is challenged with developing a skilled workforce and addressing public resistance. Wind Powering America's Wind for Schools project addresses these issues by developing Wind Application Centers (WACs) at universities; WAC students assist in implementing school wind turbines and participate in wind courses, by installing small wind turbines at community "host" schools, by implementing teacher training with interactive curricula at each host school. This poster provides an overview of the first two years of the Wind for Schools project, primarily supporting activities in Colorado, Kansas, Nebraska, South Dakota, Montana, and Idaho.

  7. Learning to forecast wind at remote sites for wind energy applications. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Notis, C.; Trettel, D.W.; Aquino, J.T.; Piazza, T.R.; Taylor, L.E.; Trask, D.C.; Wegley, H.L.; Miller, A.H.

    1983-01-01

    Observed wind patterns are correlated with synoptic or mescoscale weather systems. Six sites selected for analysis include Montauk Point, New York; Boone, North Carolina; Ludington, Michigan; Clayton, New Mexico; Amarillo, Texas; and San Gorgonio Pass, California. Objectives of the analysis are: to identify synoptic and/or mesoscale weather patterns that are associated with recognizable wind events at the sites; to define a set of criteria that uniquely describes such weather patterns; to estimate the reliability (accuracy) of forecasting rules derived from the association of weather patterns and site winds; and to attempt to separate any mesoscale effects of local topography from the synoptic-scale effects. One-to-one mapping of wind regimes onto synoptic types was not found. It was concluded that four factors should be examined when stratifying wind regimes: synoptic situation, descriptive climatology, pressure gradient vector, and winds aloft. The wind forecasting approach developed was intended for forecasting hourly average winds out to the 24 hour or possibly 36 hour time horizon. (LEW)

  8. Numerical Investigation of Wind Conditions for Roof-Mounted Wind Turbines: Effects of Wind Direction and Horizontal Aspect Ratio of a High-Rise Cuboid Building

    Directory of Open Access Journals (Sweden)

    Takaaki Kono

    2016-11-01

    Full Text Available From the viewpoint of installing small wind turbines (SWTs on rooftops, this study investigated the effects of wind direction and horizontal aspect ratio (HAR = width/length of a high-rise cuboid building on wind conditions above the roof by conducting large eddy simulations (LESs. The LES results confirmed that as HAR decreases (i.e., as the building width decreases, the variation in wind velocity over the roof tends to decrease. This tendency is more prominent as the angle between the wind direction and the normal vector of the building’s leeward face with longer roof edge increases. Moreover, at windward corners of the roof, wind conditions are generally favorable at relatively low heights. In contrast, at the midpoint of the roof's windward edge, wind conditions are generally not favorable at relatively low heights. At leeward representative locations of the roof, the bottoms of the height range of favorable wind conditions are typically higher than those at the windward representative locations, but the favorable wind conditions are much better at the leeward representative locations. When there is no prevailing wind direction, the center of the roof is more favorable for installing SWTs than the corners or the edge midpoints of the roof.

  9. Dependency distance: A new perspective on the syntactic development in second language acquisition. Comment on "Dependency distance: A new perspective on syntactic patterns in natural language" by Haitao Liu et al.

    Science.gov (United States)

    Jiang, Jingyang; Ouyang, Jinghui

    2017-07-01

    Liu et al. [1] offers a clear and informative account of the use of dependency distance in studying natural languages, with a focus on the viewpoint that dependency distance minimization (DDM) can be regarded as a linguistic universal. We would like to add the perspective of employing dependency distance in the studies of second languages acquisition (SLA), particularly the studies of syntactic development.

  10. Multithreading in vector processors

    Energy Technology Data Exchange (ETDEWEB)

    Evangelinos, Constantinos; Kim, Changhoan; Nair, Ravi

    2018-01-16

    In one embodiment, a system includes a processor having a vector processing mode and a multithreading mode. The processor is configured to operate on one thread per cycle in the multithreading mode. The processor includes a program counter register having a plurality of program counters, and the program counter register is vectorized. Each program counter in the program counter register represents a distinct corresponding thread of a plurality of threads. The processor is configured to execute the plurality of threads by activating the plurality of program counters in a round robin cycle.

  11. Twisting of paramodular vectors

    OpenAIRE

    Johnson-Leung, Jennifer; Roberts, Brooks

    2013-01-01

    Let $F$ be a non-archimedean local field of characteristic zero, let $(\\pi,V)$ be an irreducible, admissible representation of $\\GSp(4,F)$ with trivial central character, and let $\\chi$ be a quadratic character of $F^\\times$ with conductor $c(\\chi)>1$. We define a twisting operator $T_\\chi$ from paramodular vectors for $\\pi$ of level $n$ to paramodular vectors for $\\chi \\otimes \\pi$ of level $\\max(n+2c(\\chi),4c(\\chi))$, and prove that this operator has properties analogous to the well-known $...

  12. Matrix vector analysis

    CERN Document Server

    Eisenman, Richard L

    2005-01-01

    This outstanding text and reference applies matrix ideas to vector methods, using physical ideas to illustrate and motivate mathematical concepts but employing a mathematical continuity of development rather than a physical approach. The author, who taught at the U.S. Air Force Academy, dispenses with the artificial barrier between vectors and matrices--and more generally, between pure and applied mathematics.Motivated examples introduce each idea, with interpretations of physical, algebraic, and geometric contexts, in addition to generalizations to theorems that reflect the essential structur

  13. Sums and Gaussian vectors

    CERN Document Server

    Yurinsky, Vadim Vladimirovich

    1995-01-01

    Surveys the methods currently applied to study sums of infinite-dimensional independent random vectors in situations where their distributions resemble Gaussian laws. Covers probabilities of large deviations, Chebyshev-type inequalities for seminorms of sums, a method of constructing Edgeworth-type expansions, estimates of characteristic functions for random vectors obtained by smooth mappings of infinite-dimensional sums to Euclidean spaces. A self-contained exposition of the modern research apparatus around CLT, the book is accessible to new graduate students, and can be a useful reference for researchers and teachers of the subject.

  14. Compact 3D Wind Sensor for Unmanned Aerial Vehicles, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Accurate wide-area mapping of three-dimensional (3D) wind vectors plays an important role in our ability to understand climate processes, predict weather patterns...

  15. Wind loads for bar-truss structures

    Science.gov (United States)

    Katow, M. S.

    1981-01-01

    An analysis method developed to calculate the wind loads on the nodes or joints of the truss type support structure of the 64 meter antenna is described. The method uses the CBAR element and GRID coordinate cards of the NASTRAN or IDEAS structural analysis programs as inputs to the computer model of the structure. Cross flow principles and vector analysis are also used in the analysis. The algorithms used are described and probable accuracy of the solution is discussed.

  16. A general winding law of modular stellarator coils

    International Nuclear Information System (INIS)

    Harmeyer, E.; Kisslinger, J.; Rau, F.; Wobig, H.

    1985-03-01

    A general winding law for twisted coils is described in terms of analytic functions. On a toroidal surface given as x vector = x vector (φ,Θ) (φ = toroidal coordinate, Θ = poloidal coordinate) the current filaments φ = φ κ (Θ) are represented in terms of sin-functions. The paper includes several examples of classical stellarator and HELIAC configurations. By specifying a separate winding law for every single coil also WVII-AS type configurations can be modelled. The numerical code describing the central filament and the borderlines of the coils are given in the appendix. (orig.)

  17. Wind engineering in Africa

    NARCIS (Netherlands)

    Wisse, J.A.; Stigter, C.J.

    2007-01-01

    The International Association for Wind Engineering (IAWE) has very few contacts in Africa, the second-largest continent. This paper reviews important wind-related African issues. They all require data on wind climate, which are very sparse in Africa. Wind engineering in Africa can assist in

  18. Wind energy; Energie eolienne

    Energy Technology Data Exchange (ETDEWEB)

    Vachey, C.

    2000-05-01

    This public information paper presents the wind energy resource in the Languedoc Roussillon region, explains how a wind turbine works, the different types of utilization and the cost of the wind energy. The environmental impacts of the wind energy, on the noise and the landscape, are also discussed. (A.L.B.)

  19. Nuclear medium effects via quasielastic (p vector, p vector') and (p vector, n vector) scattering

    International Nuclear Information System (INIS)

    Hillhouse, G.C.; Ventel, B.I.S. van der; Wyngaardt, S.M.; De Kock, P.R.

    1997-01-01

    For a 40 Ca target at a fixed momentum transfer of 1.97 fm -1 , and incident energies between 135 and 300 MeV, we quantitatively investigate the sensitivity of complete sets of quasielastic (p vector, p vector') and (p vector, n vector) spin observables to medium effects, pseudoscalar versus pseudovector forms of the πNN vertex, and exchange contributions to the NN amplitudes using a relativistic PWIA. The qualitative nature of previous studies failed to give an indication of the experimental statistical uncertainty required for distinguishing between the various model predictions. New Horowitz-Love-Franey relativistic NN amplitudes have been generated in order to yield improved and more quantitative spin observable values than before. This study indicates at which energies particular spin observables need to be measured in order to test current nuclear models. A comparison to the limited available data indicates that the relativistic parametrization of the NN scattering amplitudes in terms of only the five Fermi invariants (the SVPAT form) is questionable. (author)

  20. Orthogonalisation of Vectors

    Indian Academy of Sciences (India)

    converting these vectors to orthonormal ones demanded by the model. The process of finding the closest or- thonormal basis is called the Lowdin orthogonalisation after the Swedish chemist P 0 Lowdin who introduced it. This is related to one of the basic theorems in linear algebra as we will see. Matrix Approximation ...

  1. Calculus with vectors

    CERN Document Server

    Treiman, Jay S

    2014-01-01

    Calculus with Vectors grew out of a strong need for a beginning calculus textbook for undergraduates who intend to pursue careers in STEM. fields. The approach introduces vector-valued functions from the start, emphasizing the connections between one-variable and multi-variable calculus. The text includes early vectors and early transcendentals and includes a rigorous but informal approach to vectors. Examples and focused applications are well presented along with an abundance of motivating exercises. All three-dimensional graphs have rotatable versions included as extra source materials and may be freely downloaded and manipulated with Maple Player; a free Maple Player App is available for the iPad on iTunes. The approaches taken to topics such as the derivation of the derivatives of sine and cosine, the approach to limits, and the use of "tables" of integration have been modified from the standards seen in other textbooks in order to maximize the ease with which students may comprehend the material. Additio...

  2. Estimation of vector velocity

    DEFF Research Database (Denmark)

    2000-01-01

    Using a pulsed ultrasound field, the two-dimensional velocity vector can be determined with the invention. The method uses a transversally modulated ultrasound field for probing the moving medium under investigation. A modified autocorrelation approach is used in the velocity estimation. The new...

  3. Sesquilinear uniform vector integral

    Indian Academy of Sciences (India)

    absolute integral which generalizes the Lebesgue integral and is more easy to manipulate. We speak so far about scalar integrals (scalar functions integrated with respect to positive measures-speaking approximately). The idea of integrating vector functions with respect to scalar measures came naturally on the scene of ...

  4. Vector-borne Infections

    Centers for Disease Control (CDC) Podcasts

    2011-04-18

    This podcast discusses emerging vector-borne pathogens, their role as prominent contributors to emerging infectious diseases, how they're spread, and the ineffectiveness of mosquito control methods.  Created: 4/18/2011 by National Center for Emerging Zoonotic and Infectious Diseases (NCEZID).   Date Released: 4/27/2011.

  5. Offshore Wind Farms

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik; Hasager, Charlotte Bay; Courtney, Michael

    2015-01-01

    The technology behind constructing wind farms offshore began to develop in 1991 when the Vindeby wind farm was installed off the Danish coast (11 Bonus 450 kW turbines). Resource assessment, grid connection, and wind farm operation are significant challenges for offshore wind power just...... concern are the problems associated with locating the turbines close together in a wind farm and the problems of placing several large wind farms in a confined area. The environmental impacts of offshore wind farms are also treated, but not the supply chain, that is, the harbors, the installation vessels...

  6. Direct vector controlled six-phase asymmetrical induction motor with power balanced space vector PWM multilevel operation

    DEFF Research Database (Denmark)

    Padmanaban, Sanjeevi Kumar; Grandi, Gabriele; Ojo, Joseph Olorunfemi

    2016-01-01

    -winding terminals. An original synchronous field oriented control (FOC) algorithm with three variables as degree of freedom is proposed, allowing power sharing among the four VSIs in symmetric/asymmetric conditions. A standard three-level space vector pulse width modulation (SVPWM) by nearest three vector (NTV......) approach was adopted for each couple of VSIs to operate as multilevel output voltage generators. The proposed power sharing algorithm is verified for the ac drive system by observing the dynamic behaviours in different set conditions by complete simulation modelling in software (Matlab...

  7. Linguistic complex networks as a young field of quantitative linguistics. Comment on "Approaching human language with complex networks" by J. Cong and H. Liu

    Science.gov (United States)

    Köhler, Reinhard

    2014-12-01

    We have long been used to the domination of qualitative methods in modern linguistics. Indeed, qualitative methods have advantages such as ease of use and wide applicability to many types of linguistic phenomena. However, this shall not overshadow the fact that a great part of human language is amenable to quantification. Moreover, qualitative methods may lead to over-simplification by employing the rigid yes/no scale. When variability and vagueness of human language must be taken into account, qualitative methods will prove inadequate and give way to quantitative methods [1, p. 11]. In addition to such advantages as exactness and precision, quantitative concepts and methods make it possible to find laws of human language which are just like those in natural sciences. These laws are fundamental elements of linguistic theories in the spirit of the philosophy of science [2,3]. Theorization effort of this type is what quantitative linguistics [1,4,5] is devoted to. The review of Cong and Liu [6] has provided an informative and insightful survey of linguistic complex networks as a young field of quantitative linguistics, including the basic concepts and measures, the major lines of research with linguistic motivation, and suggestions for future research.

  8. Zhutheca Liu, Li et Hilton gen. nov., the fertile pinnules of Fascipteris densata Gu et Zhi and their significance in marattialean evolution.

    Science.gov (United States)

    Liu; Li; Hilton

    2000-04-01

    The morphology of the fertile pinnules of Fascipteris densata Gu et Zhi have been subjected to a detailed morphological investigation based on recently collected specimens from the Upper Permian of Yunnan Province, south China. These investigations have revealed that this species possesses synangia of the Asterotheca-type, situated in two or three rows either side of the midrib on a Fascipteris-type pinnule. This arrangement of Asterotheca-type synangia is extremely unusual considering that all other reports of this genus are with a single row of synangia located on each side of the midrib of a pecopteroid-type pinnule. As a consequence of this unique morphological arrangement, a new genus, Zhutheca densata Liu, Li et Hilton gen. et comb. nov. has been created to distinguish this material from other specimens of the Asterotheca and Fascipteris types. The structure and arrangement of the fertile pinnule of Zhutheca are compared with other Palaeozoic and Mesozoic marattialean taxa with which it shares certain features of its morphology. In addition, the stratigraphic, evolutionary and phylogenetic significance of Zhutheca are considered in detail.

  9. Dependency distance distribution - from the perspective of genre variation. Comment on "Dependency distance: a new perspective on syntactic patterns in natural languages" by Haitao Liu et al.

    Science.gov (United States)

    Wang, Yaqin

    2017-07-01

    Language can be regarded as a system where different components fit together, according to Saussure [1]. Likewise, the central axiom of synergetic linguistic is that language is a self-organized and self-adapting system. One of its main concerns is to view language as ;a psycho-social phenomenon and a biological-cognitive one at the same time; [2, 760]. Based on this assumption, Liu, Xu and Liang propose a novel approach, i.e., dependency distance, to study the general tendency hidden beneath diverse human languages [3]. As the authors describe in sections 1-3, variations within and between human languages all show the similar tendency towards dependency distance minimization (DDM). In sections 4-5, they introduce certain syntactic patterns related to both short and long dependency distances. However, the effect of genre seems to be given less sufficient attention by the authors. A study suggests that different distributions of closeness and degree centralities across genres can broaden the understanding of dependency distance distribution [4]. Another one shows that different genres have different parameters in terms of modeling dependency distance distribution [5]. Further research on the genre variation, therefore, can provide additional support for this issue.

  10. Wind power. [electricity generation

    Science.gov (United States)

    Savino, J. M.

    1975-01-01

    A historical background on windmill use, the nature of wind, wind conversion system technology and requirements, the economics of wind power and comparisons with alternative systems, data needs, technology development needs, and an implementation plan for wind energy are presented. Considerable progress took place during the 1950's. Most of the modern windmills feature a wind turbine electricity generator located directly at the top of their rotor towers.

  11. The CMEMS L3 scatterometer wind product

    Science.gov (United States)

    de Kloe, Jos; Stoffelen, Ad; Verhoef, Anton

    2017-04-01

    Within the Copernicus Marine Environment Monitoring Service KNMI produces several ocean surface Level 3 wind products. These are daily updated global maps on a regular grid of the available scatterometer wind observations and derived properties, and produced from our EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI SAF) operational near-real time (NRT) Level 2 swath-based wind products by linear interpolation. Currently available products are the ASCAT on Metop A/B stress equivalent wind vectors, accompanied by ECMWF NWP reference stress equivalent winds from the operational ECMWF NWP model. For each ASCAT scatterometer we provide products on 2 different resolutions, 0.25 and 0.125 degrees. In addition we provide wind stress vectors, and derivative fields (curl and divergence) for stress equivalent wind and wind stress, both for the observations and for the NWP reference winds. New NRT scatterometer products will be made available when additional scatterometer instruments become available, and NRT access to the data can be arranged. We hope OSCAT on the Indian ScatSat-1 satellite will be the the next NRT product to be added. In addition multi-year reprocessing datasets have been made available for ASCAT on Metop-A (1-Jan-2007 up to 31-Mar-2014) and Seawinds on QuikScat (19-Jul-1999 up to 21-Nov-2009). For ASCAT 0.25 and 0.125 degree resolution products are provided, and for QuikScat 0.50 and 0.25 degree resolution products are provided, These products are based on reprocessing the L2 scatterometer products with the latest processing software version, and include reference winds from the ECMWF ERA-Interim model. Additional reprocessing datasets will be added when reprocessed L2 datasets become available. This will hopefully include the ERS-1 and ERS-2 scatterometer datasets (1992-2001), which will extend the available date range back to 1992. These products are available for download through the CMEMS portal website: http://marine.copernicus.eu/

  12. Simulation of Wind-Battery Microgrid Based on Short-Term Wind Power Forecasting

    Directory of Open Access Journals (Sweden)

    Konstantinos N. Genikomsakis

    2017-11-01

    Full Text Available The inherently intermittent and highly variable nature of wind necessitates the use of wind power forecasting tools in order to facilitate the integration of wind turbines in microgrids, among others. In this direction, the present paper describes the development of a short-term wind power forecasting model based on artificial neural network (ANN clustering, which uses statistical feature parameters in the input vector, as well as an enhanced version of this approach that adjusts the ANN output with the probability of lower misclassification (PLM method. Moreover, it employs the Monte Carlo simulation to represent the stochastic variation of wind power production and assess the impact of energy management decisions in a residential wind-battery microgrid using the proposed wind power forecasting models. The results indicate that there are significant benefits for the microgrid when compared to the naïve approach that is used for benchmarking purposes, while the PLM adjustment method provides further improvements in terms of forecasting accuracy.

  13. Doppler Lidar Vector Retrievals and Atmospheric Data Visualization in Mixed/Augmented Reality

    Science.gov (United States)

    Cherukuru, Nihanth Wagmi

    Environmental remote sensing has seen rapid growth in the recent years and Doppler wind lidars have gained popularity primarily due to their non-intrusive, high spatial and temporal measurement capabilities. While lidar applications early on, relied on the radial velocity measurements alone, most of the practical applications in wind farm control and short term wind prediction require knowledge of the vector wind field. Over the past couple of years, multiple works on lidars have explored three primary methods of retrieving wind vectors viz., using homogeneous windfield assumption, computationally extensive variational methods and the use of multiple Doppler lidars. Building on prior research, the current three-part study, first demonstrates the capabilities of single and dual Doppler lidar retrievals in capturing downslope windstorm-type flows occurring at Arizona's Barringer Meteor Crater as a part of the METCRAX II field experiment. Next, to address the need for a reliable and computationally efficient vector retrieval for adaptive wind farm control applications, a novel 2D vector retrieval based on a variational formulation was developed and applied on lidar scans from an offshore wind farm and validated with data from a cup and vane anemometer installed on a nearby research platform. Finally, a novel data visualization technique using Mixed Reality (MR)/ Augmented Reality (AR) technology is presented to visualize data from atmospheric sensors. MR is an environment in which the user's visual perception of the real world is enhanced with live, interactive, computer generated sensory input (in this case, data from atmospheric sensors like Doppler lidars). A methodology using modern game development platforms is presented and demonstrated with lidar retrieved wind fields. In the current study, the possibility of using this technology to visualize data from atmospheric sensors in mixed reality is explored and demonstrated with lidar retrieved wind fields as well as

  14. Wind gust measurements using pulsed Doppler wind-lidar: comparison of direct and indirect techniques

    DEFF Research Database (Denmark)

    wind vector, we need information from at least three different lines of sight pointing towards different directions. The instrument sensitivity depends on the amount of aerosol present and the velocity measurement uncertainty is directly related to the amount of signal. With the commercial lidars...... traditionally used today it takes several seconds to measure each line of sight with sufficient sensitivity and therefore the temporal resolution of the wind measurement is of the order of tens of seconds, which is not sufficient for gusts. Here we deploy a fast scanning lidar (temporal resolution for a scan...

  15. Climatic wind tunnel for wind engineering tasks

    Czech Academy of Sciences Publication Activity Database

    Kuznetsov, Sergeii; Pospíšil, Stanislav; Král, Radomil

    2015-01-01

    Roč. 112, 2-B (2015), s. 303-316 ISSN 1897-628X R&D Projects: GA ČR(CZ) GA14-12892S Keywords : climatic tunnel * wind tunnel * atmospheric boundary layer * flow resistance * wind tunnel contraction Subject RIV: JM - Building Engineering https://suw.biblos.pk.edu.pl/resources/i5/i6/i6/i7/i6/r56676/KuznetsovS_ClimaticWind.pdf

  16. Wind Atlas for Egypt

    DEFF Research Database (Denmark)

    Mortensen, Niels Gylling; Said Said, Usama; Badger, Jake

    2006-01-01

    The results of a comprehensive, 8-year wind resource assessment programme in Egypt are presented. The objective has been to provide reliable and accurate wind atlas data sets for evaluating the potential wind power output from large electricityproducing wind turbine installations. The regional wind...... climates of Egypt have been determined by two independent methods: a traditional wind atlas based on observations from more than 30 stations all over Egypt, and a numerical wind atlas based on long-term reanalysis data and a mesoscale model (KAMM). The mean absolute error comparing the two methods is about...... 10% for two large-scale KAMM domains covering all of Egypt, and typically about 5% for several smaller-scale regional domains. The numerical wind atlas covers all of Egypt, whereas the meteorological stations are concentrated in six regions. The Wind Atlas for Egypt represents a significant step...

  17. Wind Atlas for Egypt

    DEFF Research Database (Denmark)

    The results of a comprehensive, 8-year wind resource assessment programme in Egypt are presented. The objective has been to provide reliable and accurate wind atlas data sets for evaluating the potential wind power output from large electricityproducing wind turbine installations. The regional wind...... climates of Egypt have been determined by two independent methods: a traditional wind atlas based on observations from more than 30 stations all over Egypt, and a numerical wind atlas based on long-term reanalysis data and a mesoscale model (KAMM). The mean absolute error comparing the two methods is about...... 10% for two large-scale KAMM domains covering all of Egypt, and typically about 5% for several smaller-scale regional domains. The numerical wind atlas covers all of Egypt, whereas the meteorological stations are concentrated in six regions. The Wind Atlas for Egypt represents a significant step...

  18. Vector-borne diseases

    DEFF Research Database (Denmark)

    More, Simon J.; Bicout, Dominique; Bøtner, Anette

    2017-01-01

    After a request from the Europea n Commission, EFSA’s Panel on Animal Health and Welfaresummarised the main characteristics of 36 vector-borne disease s (VBDs) in 36 web-based storymaps.The risk of introduction in the EU through movement of livestock or pets was assessed for eac h of the36 VBDs...... individually, using a semiquantitative Metho d to INTegrate all relevant RISK aspects(MINTRI SK model), which was further modified to a European scale into the EFSA-VBD-RISK-m odel .Only eight of the 36 VBD-agents had an overall rate of introduction in the EU (being the combinationof the rate of entry, vector...... transmission and establishment) which was estimated to be above 0.001introductions per year. These were Crimean-Congo haemorrhagic fever virus, bluetongue virus, WestNile virus, Schmallenberg virus, Hepatozoon canis, Leishmania infantum, Bunyamwera virus andHighlands J. virus. For these eight dise ases...

  19. Extreme wind estimate for Hornsea wind farm

    DEFF Research Database (Denmark)

    Larsén, Xiaoli Guo

    The purpose of this study is to provide estimation of the 50-year winds of 10 min and 1-s gust value at hub height of 100 m, as well as the design parameter shear exponent for the Hornsea offshore wind farm. The turbulence intensity required for estimating the gust value is estimated using two ap....... The greatest sector-wise extreme winds are from west to northwest. Different data, different periods and different methods have provided a range of values of the 50-year wind and accordingly the gust values, as summarized in Table 15.......The purpose of this study is to provide estimation of the 50-year winds of 10 min and 1-s gust value at hub height of 100 m, as well as the design parameter shear exponent for the Hornsea offshore wind farm. The turbulence intensity required for estimating the gust value is estimated using two...... approaches. One is through the measurements from the wind Doppler lidar, WindCube, which implies serious uncertainty, and the other one is through similarity theory for the atmospheric surface layer where the hub height is likely to belong to during strong storms. The turbulence intensity for storm wind...

  20. Wind power electric systems modeling, simulation and control

    CERN Document Server

    Rekioua, Djamila

    2014-01-01

    The book helps readers understand key concepts in standalone and grid connected wind energy systems and features analysis into the modeling and optimization of commonly used configurations through the implementation of different control strategies.Utilizing several electrical machinery control approaches, such as vector control and direct torque control 'Wind Power Electric Systems' equips readers with the means to understand, assess and develop their own wind energy systems and to evaluate the performance of such systems.Mathematical models are provided for each system and a corresponding MAT

  1. Effects of wind turbine wake on atmospheric sound propagation

    DEFF Research Database (Denmark)

    Barlas, Emre; Zhu, Wei Jun; Shen, Wen Zhong

    2017-01-01

    In this paper, we investigate the sound propagation from a wind turbine considering the effects of wake-induced velocity deficit and turbulence. In order to address this issue, an advanced approach was developed in which both scalar and vector parabolic equations in two dimensions are solved. Flow...... field input was obtained using the actuator line (AL) technique with Large Eddy Simulation (LES) to model the wind turbine and its wake and from an analytical wake model. The effect of incoming wind speed and atmospheric stability was investigated with the analytical wake input using a single point...

  2. Tensor Calculus: Unlearning Vector Calculus

    Science.gov (United States)

    Lee, Wha-Suck; Engelbrecht, Johann; Moller, Rita

    2018-01-01

    Tensor calculus is critical in the study of the vector calculus of the surface of a body. Indeed, tensor calculus is a natural step-up for vector calculus. This paper presents some pitfalls of a traditional course in vector calculus in transitioning to tensor calculus. We show how a deeper emphasis on traditional topics such as the Jacobian can…

  3. Propagating Gateway Vectors.

    Science.gov (United States)

    Reece-Hoyes, John S; Walhout, Albertha J M

    2018-01-02

    Generating stocks of Entry and Destination vectors for use in the Gateway recombinatorial cloning system requires transforming them into Escherichia coli strain DB3.1, where they can replicate because this strain is immune to the effects of the ccdB gene carried in the Gateway cassette. However, mutations in the ccdB gene can arise at low frequency, and these mutant plasmids will consequently allow growth of standard cloning strains of E. coli (e.g., DH5α). Therefore, after making new stocks of Gateway plasmids, their ability to grow in cloning strains of E. coli must be tested. This involves obtaining multiple stocks of vector, each arising from a single plasmid grown in a single DB3.1 bacterial colony, and transforming each stock into both DB3.1 and the preferred cloning strain of E. coli in a controlled fashion. Only vector stocks that effectively kill the standard cloning strain (i.e., no or few colonies are obtained after transformation) should be used in Gateway cloning reactions. The sequence can be performed in 3 d. © 2018 Cold Spring Harbor Laboratory Press.

  4. Adaptive path following for Unmanned Aerial Vehicles in time-varying unknown wind environments

    NARCIS (Netherlands)

    Zhou, Bingyu; Satyavada, Harish; Baldi, S.; Sun, J.; Rajamani, R.

    2017-01-01

    In this paper, an adaptive control scheme for Unmanned Aerial Vehicles (UAVs) path following under slowly time-varying wind is developed. The proposed control strategy integrates the path following law based on the vector field method with an adaptive term counteracting the effect of wind's

  5. Offshore wind energy developments

    DEFF Research Database (Denmark)

    Stolpe, Mathias; Buhl, Thomas; Sumer, B. Mutlu

    2014-01-01

    This chapter will give a brief overview of a few of the activities within offshore wind energy research, specifically 1) Support structure optimization, 2) Blade coatings for wind turbines; 3) Scour protection of foundations, 4) Offshore HVDC and 5) Offshore wind services.......This chapter will give a brief overview of a few of the activities within offshore wind energy research, specifically 1) Support structure optimization, 2) Blade coatings for wind turbines; 3) Scour protection of foundations, 4) Offshore HVDC and 5) Offshore wind services....

  6. Wind energy information guide

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-04-01

    This book is divided into nine chapters. Chapters 1--8 provide background and annotated references on wind energy research, development, and commercialization. Chapter 9 lists additional sources of printed information and relevant organizations. Four indices provide alphabetical access to authors, organizations, computer models and design tools, and subjects. A list of abbreviations and acronyms is also included. Chapter topics include: introduction; economics of using wind energy; wind energy resources; wind turbine design, development, and testing; applications; environmental issues of wind power; institutional issues; and wind energy systems development.

  7. Wind Power Career Chat

    Energy Technology Data Exchange (ETDEWEB)

    2011-01-01

    This document will teach students about careers in the wind energy industry. Wind energy, both land-based and offshore, is expected to provide thousands of new jobs in the next several decades. Wind energy companies are growing rapidly to meet America's demand for clean, renewable, and domestic energy. These companies need skilled professionals. Wind power careers will require educated people from a variety of areas. Trained and qualified workers manufacture, construct, operate, and manage wind energy facilities. The nation will also need skilled researchers, scientists, and engineers to plan and develop the next generation of wind energy technologies.

  8. Arctic wind energy

    International Nuclear Information System (INIS)

    Peltola, E.; Holttinen, H.; Marjaniemi, M.; Tammelin, B.

    1998-01-01

    Arctic wind energy research was aimed at adapting existing wind technologies to suit the arctic climatic conditions in Lapland. Project research work included meteorological measurements, instrument development, development of a blade heating system for wind turbines, load measurements and modelling of ice induced loads on wind turbines, together with the development of operation and maintenance practices in arctic conditions. As a result the basis now exists for technically feasible and economically viable wind energy production in Lapland. New and marketable products, such as blade heating systems for wind turbines and meteorological sensors for arctic conditions, with substantial export potential, have also been developed. (orig.)

  9. Arctic wind energy

    Energy Technology Data Exchange (ETDEWEB)

    Peltola, E. [Kemijoki Oy (Finland); Holttinen, H.; Marjaniemi, M. [VTT Energy, Espoo (Finland); Tammelin, B. [Finnish Meteorological Institute, Helsinki (Finland)

    1998-12-31

    Arctic wind energy research was aimed at adapting existing wind technologies to suit the arctic climatic conditions in Lapland. Project research work included meteorological measurements, instrument development, development of a blade heating system for wind turbines, load measurements and modelling of ice induced loads on wind turbines, together with the development of operation and maintenance practices in arctic conditions. As a result the basis now exists for technically feasible and economically viable wind energy production in Lapland. New and marketable products, such as blade heating systems for wind turbines and meteorological sensors for arctic conditions, with substantial export potential, have also been developed. (orig.)

  10. Wind power today

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-04-01

    This publication highlights initiatives of the US DOE`s Wind Energy Program. 1997 yearly activities are also very briefly summarized. The first article describes a 6-megawatt wind power plant installed in Vermont. Another article summarizes technical advances in wind turbine technology, and describes next-generation utility and small wind turbines in the planning stages. A village power project in Alaska using three 50-kilowatt turbines is described. Very brief summaries of the Federal Wind Energy Program and the National Wind Technology Center are also included in the publication.

  11. Large-scale, high-resolution wind resource mapping for wind farm planning and development in South Africa

    DEFF Research Database (Denmark)

    Mortensen, Niels Gylling; Badger, Jake; Hansen, Jens Carsten

    2014-01-01

    -climatological inputs to the wind resource mapping are wind atlas data sets derived from mesoscale modelling using the Karlsruhe Atmospheric Mesoscale Model (KAMM). The topographical inputs to the microscale modelling are 20-m digital height contours from 1:50,000 South African topographical maps and vector-format land...... estimates are designed for national and provincial planning and strategic environmental impact assessment for wind power in South Africa and the results have therefore been made available in common GIS formats. The database of results is in the public domain and can be downloaded from the WASA web site...

  12. Optimizing Lidar Scanning Strategies for Wind Energy Measurements (Invited)

    Science.gov (United States)

    Newman, J. F.; Bonin, T. A.; Klein, P.; Wharton, S.; Chilson, P. B.

    2013-12-01

    Environmental concerns and rising fossil fuel prices have prompted rapid development in the renewable energy sector. Wind energy, in particular, has become increasingly popular in the United States. However, the intermittency of available wind energy makes it difficult to integrate wind energy into the power grid. Thus, the expansion and successful implementation of wind energy requires accurate wind resource assessments and wind power forecasts. The actual power produced by a turbine is affected by the wind speeds and turbulence levels experienced across the turbine rotor disk. Because of the range of measurement heights required for wind power estimation, remote sensing devices (e.g., lidar) are ideally suited for these purposes. However, the volume averaging inherent in remote sensing technology produces turbulence estimates that are different from those estimated by a sonic anemometer mounted on a standard meteorological tower. In addition, most lidars intended for wind energy purposes utilize a standard Doppler beam-swinging or Velocity-Azimuth Display technique to estimate the three-dimensional wind vector. These scanning strategies are ideal for measuring mean wind speeds but are likely inadequate for measuring turbulence. In order to examine the impact of different lidar scanning strategies on turbulence measurements, a WindCube lidar, a scanning Halo lidar, and a scanning Galion lidar were deployed at the Southern Great Plains Atmospheric Radiation Measurement (ARM) site in Summer 2013. Existing instrumentation at the ARM site, including a 60-m meteorological tower and an additional scanning Halo lidar, were used in conjunction with the deployed lidars to evaluate several user-defined scanning strategies. For part of the experiment, all three scanning lidars were pointed at approximately the same point in space and a tri-Doppler analysis was completed to calculate the three-dimensional wind vector every 1 second. In another part of the experiment, one of

  13. Chow-Liu trees are sufficient predictive models for reproducing key features of functional networks of periictal EEG time-series.

    Science.gov (United States)

    Steimer, Andreas; Zubler, Frédéric; Schindler, Kaspar

    2015-09-01

    Seizure freedom in patients suffering from pharmacoresistant epilepsies is still not achieved in 20-30% of all cases. Hence, current therapies need to be improved, based on a more complete understanding of ictogenesis. In this respect, the analysis of functional networks derived from intracranial electroencephalographic (iEEG) data has recently become a standard tool. Functional networks however are purely descriptive models and thus are conceptually unable to predict fundamental features of iEEG time-series, e.g., in the context of therapeutical brain stimulation. In this paper we present some first steps towards overcoming the limitations of functional network analysis, by showing that its results are implied by a simple predictive model of time-sliced iEEG time-series. More specifically, we learn distinct graphical models (so called Chow-Liu (CL) trees) as models for the spatial dependencies between iEEG signals. Bayesian inference is then applied to the CL trees, allowing for an analytic derivation/prediction of functional networks, based on thresholding of the absolute value Pearson correlation coefficient (CC) matrix. Using various measures, the thus obtained networks are then compared to those which were derived in the classical way from the empirical CC-matrix. In the high threshold limit we find (a) an excellent agreement between the two networks and (b) key features of periictal networks as they have previously been reported in the literature. Apart from functional networks, both matrices are also compared element-wise, showing that the CL approach leads to a sparse representation, by setting small correlations to values close to zero while preserving the larger ones. Overall, this paper shows the validity of CL-trees as simple, spatially predictive models for periictal iEEG data. Moreover, we suggest straightforward generalizations of the CL-approach for modeling also the temporal features of iEEG signals. Copyright © 2015 Elsevier Inc. All rights

  14. Supplementing Oscat winds with Saral Altika observations for cyclone studies

    Science.gov (United States)

    Niharika, K.; Usha Sundari, H. S. V.; Prasad, A. V. V.; Kumari, E. V. S. Sita; Dadhwal, V. K.; Ali, M. M.

    2014-11-01

    Accurate prediction of life cycle of cyclone is very critical to the disaster management practices. Since the cyclones originate over the oceans where in situ observations are limited, we have to resort to the remote sensing techniques. Both optical and microwave sensors help studying the cyclones. While scatterometer provide wind vectors, altimeters can give only wind speed. In this paper we present how altimeter measurements can supplement the scatterometer observations in determining the radius of maximum winds (RMW). Sustained maximum winds, indicator for the intensity of the cyclone, are within the eye wall of a cyclone at a distance of RMW. This parameter is also useful in predicting right time of the storm surge. In this paper we used the wind speed estimations from AltiKa, an altimeter operating at Ka band.

  15. Leishmaniasis vector behaviour in Kenya

    International Nuclear Information System (INIS)

    Mutinga, M.J.

    1980-01-01

    Leishmaniasis in Kenya exists in two forms: cutaneous and visceral. The vectors of visceral leishmaniasis have been the subject of investigation by various researchers since World War II, when the outbreak of the disease was first noticed. The vectors of cutaneous leishmaniasis were first worked on only a decade ago after the discovery of the disease focus in Mt. Elgon. The vector behaviour of these diseases, namely Phlebotomus pedifer, the vector of cutaneous leishmaniasis, and Phlebotomus martini, the vector of visceral leishmaniasis, are discussed in detail. P. pedifer has been found to breed and bite inside caves, whereas P. martini mainly bites inside houses. (author)

  16. Evolution of wind towards wind turbine

    NARCIS (Netherlands)

    Giyanani, A.H.; Bierbooms, W.A.A.M.; Van Bussel, G.J.W.

    2015-01-01

    Remote sensing of the atmospheric variables with the use of LiDAR is a relatively new technology field for wind resource assessment in wind energy. The validation of LiDAR measurements and comparisons is of high importance for further applications of the data.

  17. 5MW Direct Drive Wind Turbine Generator Design

    DEFF Research Database (Denmark)

    Zaidi, Arsalan; Senn, Lucile; Ortega, Iratxe

    2012-01-01

    A 5MW direct drive offshore wind turbine generator was studied and simulated using Vector Fields OPERA. This software allows calculation of the flux density, force, torque, and eddy currents in the machine at different rotor positions. Based on the data obtained from the model, initial assumptions...

  18. WindScanner.dk - a new Remote Sensing based Research Infrastructure for on- and offshore Wind Energy Research

    DEFF Research Database (Denmark)

    Mikkelsen, Torben

    obtained in planetary boundary layer turbulent flow have been acquired from both ground-based and wind turbine-integrated space by time and space synchronized scanning lidars. Results to date include: turbulent inflow over complex terrain scanned in a horizontal-vertical 2D scan plane, and 2-dimensional...... and 3-dimensional wind vector scan measurements obtained during various WindScanner boundary-layer field campaigns. A special designed `2D upwind rotor plane scanning SpinnerLidar', mounted in the rotating spinner, and able to provide the wind turbine control systems with detailed upwind feed......-forward inflow information, is also investigated as a provider of rotor plane inflow for accurate power curve measurements. The instrument development involves both a short range (10 -200 m) and a long-range (100 - 6000 m) synchronized 3D scanning wind lidar system....

  19. Characterization of wind velocities in the upstream induction zone of a wind turbine using scanning continuous-wave lidars

    DEFF Research Database (Denmark)

    Simley, Eric; Angelou, Nikolas; Mikkelsen, Torben Krogh

    2016-01-01

    9% and 3% of the freestream longitudinal wind speed were measured for the abovementioned high and low CP values, respectively. Turbulence statistics, calculated using 2.5-min time series, suggest that the standard deviation of the longitudinal wind component decreases close to the rotor, while...... Technical University’s Risø campus is investigated using a scanning Light Detection and Ranging (lidar) system. Three short-range continuous-wave “WindScanner” lidars are positioned in the field around the V27 turbine allowing detection of all three components of the wind velocity vectors within...... the induction zone. The time-averaged mean wind speeds at different locations in the upstream induction zone are measured by scanning a horizontal plane at hub height and a vertical plane centered at the middle of the rotor extending roughly 1.5 rotor diameters (D) upstream of the rotor. Turbulence statistics...

  20. Wind Tunnel Measurements at LM Wind Power

    DEFF Research Database (Denmark)

    Bertagnolio, Franck

    2012-01-01

    The optimization of airfoil profiles specifically designed for wind turbine application was initiated in the late 80’s [67, 68, 30, 15]. The first attempts to reduce airfoil noise for wind turbines made use of airfoil trailing edge serration. Themodification of airfoil shapes targeted at noise...... reduction is more recent. An important effort was produced in this direction within the SIROCCO project. This latter work involved measurements on full size wind turbines and showed that trailing edge serration may proved a viable solution for mitigating wind turbine noise though it has not been implemented...... on commercial wind turbine yet. It should be mentioned here that the attenuation of turbulent inflow noise using wavy leading edge has recently been investigated [55], but this technique has still to be further validated for practical applications. In this paper, it is proposed to optimize an airfoil which...

  1. An evaluation of the WindEye wind lidar

    DEFF Research Database (Denmark)

    Dellwik, Ebba; Sjöholm, Mikael; Mann, Jakob

    Prevision of the wind field by remote sensing wind lidars has the potential to improve the performance of wind turbines. The functionality of a WindEye lidar developed by Windar Photonics A/S (Denmark) for the wind energy market was tested in a two months long field experiment. The WindEye sensor...... with a high accuracy during the whole campaign....

  2. Wind electric power generation

    International Nuclear Information System (INIS)

    Koch, M.K.; Wind, L.; Canter, B.; Moeller, T.

    2001-01-01

    The monthly statistics of wind electric power generation in Denmark are compiled from information given by the owners of the private wind turbines. For each wind turbine the name of the site and of the type of turbine is given, and the power generation data are given for the month in question together with the total production in 1999 and 2000. Also the data of operation start are given. On the map of Denmark the sites of the wind turbines are marked. (CLS)

  3. The Irish Wind Atlas

    Energy Technology Data Exchange (ETDEWEB)

    Watson, R. [Univ. College Dublin, Dept. of Electronic and Electrical Engineering, Dublin (Ireland); Landberg, L. [Risoe National Lab., Meteorology and Wind Energy Dept., Roskilde (Denmark)

    1999-03-01

    The development work on the Irish Wind Atlas is nearing completion. The Irish Wind Atlas is an updated improved version of the Irish section of the European Wind Atlas. A map of the irish wind resource based on a WA{sup s}P analysis of the measured data and station description of 27 measuring stations is presented. The results of previously presented WA{sup s}P/KAMM runs show good agreement with these results. (au)

  4. Turbulence and wind turbines

    DEFF Research Database (Denmark)

    Brand, Arno J.; Peinke, Joachim; Mann, Jakob

    2011-01-01

    The nature of turbulent flow towards, near and behind a wind turbine, the effect of turbulence on the electricity production and the mechanical loading of individual and clustered wind turbines, and some future issues are discussed.......The nature of turbulent flow towards, near and behind a wind turbine, the effect of turbulence on the electricity production and the mechanical loading of individual and clustered wind turbines, and some future issues are discussed....

  5. On vector equilibrium problem

    Indian Academy of Sciences (India)

    Let X be a real topological vector space; K & X be a nonempty closed convex set; ЕYY PЖ be a real ordered ... induced by a solid pointed closed convex cone P, thus x P y@Ay └ x P P, VxY y P Y; f : X ┬ X└3Y with .... tone; VxY y P K, the function t P Й0Y 1К└3gЕty З Е1 └ tЖxY yЖ is continuous at 0З; g is a P-convex and ...

  6. Scalar and vector Galileons

    Science.gov (United States)

    Rodríguez, Yeinzon; Navarro, Andrés A.

    2017-03-01

    An alternative for the construction of fundamental theories is the introduction of Galileons. These are fields whose action leads to non higher than second-order equations of motion. As this is a necessary but not sufficient condition to make the Hamiltonian bounded from below, as long as the action is not degenerate, the Galileon construction is a way to avoid pathologies both at the classical and quantum levels. Galileon actions are, therefore, of great interest in many branches of physics, specially in high energy physics and cosmology. This proceedings contribution presents the generalities of the construction of both scalar and vector Galileons following two different but complimentary routes.

  7. A Nonlinear Optimization Algorithm for WindSat Wind Vector Retrievals

    Science.gov (United States)

    2006-03-01

    reflection model. The authors also thank B. Johnston and L. Connor for their as- sistance in assembling the collocated datasets and E. Twarog for comments...are available at www.remss.com. REFERENCES [1] P. W. Gaiser, K. M. St. Germain, E. M. Twarog , G. A. Poe, W. Purdy, D. Richardson, W. Grossman, W. L

  8. Wind Power Now!

    Science.gov (United States)

    Inglis, David Rittenhouse

    1975-01-01

    The government promotes and heavily subsidizes research in nuclear power plants. Federal development of wind power is slow in comparison even though much research with large wind-electric machines has already been conducted. Unless wind power programs are accelerated it will not become a major energy alternative to nuclear power. (MR)

  9. Power from the Wind

    Science.gov (United States)

    Roman, Harry T.

    2004-01-01

    Wind energy is the fastest-growing renewable energy source in the world. Over the last 20 years, the wind industry has done a very good job of engineering machines, improving materials, and economies of production, and making this energy source a reality. Like all renewable energy forms, wind energy's successful application is site specific. Also,…

  10. Extreme winds in Denmark

    DEFF Research Database (Denmark)

    Kristensen, L.; Rathmann, O.; Hansen, S.O.

    1999-01-01

    Wind-speed data from four sites in Denmark have been analyzed in order to obtain estimates of the basic wind velocity, defined as the 50-year wind speed (ten minute averages) under standard conditions, i.e. 10 meter over a homogeneous terrain with the roughness length 0.05 m. The sites are Skjern...

  11. Extreme winds in Denmark

    DEFF Research Database (Denmark)

    Kristensen, L.; Rathmann, Ole; Hansen, S.O.

    1999-01-01

    Wind-speed data from four sites in Denmark have been analyzed in order to obtain estimates of the basic wind velocity which is defined as the 50-year wind speed under standard conditions, i.e. ten-minute averages at the height 10 m over a uniform terrainwith the roughness length 0.05 m. The sites...

  12. Modelling Wind for Wind Farm Layout Optimization Using Joint Distribution of Wind Speed and Wind Direction

    DEFF Research Database (Denmark)

    Feng, Ju; Shen, Wen Zhong

    2015-01-01

    Reliable wind modelling is of crucial importance for wind farm development. The common practice of using sector-wise Weibull distributions has been found inappropriate for wind farm layout optimization. In this study, we propose a simple and easily implementable method to construct joint distribu......Reliable wind modelling is of crucial importance for wind farm development. The common practice of using sector-wise Weibull distributions has been found inappropriate for wind farm layout optimization. In this study, we propose a simple and easily implementable method to construct joint...... quite well in terms of the coefficient of determination R-2. Then, the best of these joint distributions is used in the layout optimization of the Horns Rev 1 wind farm and the choice of bin sizes for wind speed and wind direction is also investigated. It is found that the choice of bin size for wind...... direction is especially critical for layout optimization and the recommended choice of bin sizes for wind speed and wind direction is finally presented....

  13. Wind and Yaw correlation

    DEFF Research Database (Denmark)

    Federici, Paolo; Kock, Carsten Weber

    The report describes measurements carried out on a given turbine and period. The measurements are carried out in accordance to Ref. [1]. A comparison between wind speed and wind direction on the met mast and nacelle wind speed and yaw direction is made in accordance to Ref. [2] and the results...... are presented on graphs and in a table....

  14. Wind power soars

    Energy Technology Data Exchange (ETDEWEB)

    Flavin, C. [Worldwatch Inst., Washington, DC (United States)

    1996-12-31

    Opinions on the world market for wind power are presented in this paper. Some data for global wind power generating capacity are provided. European and other markets are discussed individually. Estimated potential for wind power is given for a number of countries. 3 figs.

  15. Wind power outlook 2006

    Energy Technology Data Exchange (ETDEWEB)

    anon.

    2006-04-15

    This annual brochure provides the American Wind Energy Association's up-to-date assessment of the wind industry in the United States. This 2006 general assessment shows positive signs of growth, use and acceptance of wind energy as a vital component of the U.S. energy mix.

  16. Wind and Yaw correlation

    DEFF Research Database (Denmark)

    Federici, Paolo; Kock, Carsten Weber

    The report describes measurements carried out on a given turbine and period. The measurements are carried out in accordance to Ref. [1]. A comparison between wind speed and wind direction on the met mast and nacelle wind speed and yaw direction is made in accordance to Ref. [2] and the results...

  17. Wind: French revolutions

    International Nuclear Information System (INIS)

    Jones, C.

    2006-01-01

    Despite having the second best wind resources in Europe after the UK, the wind industry in France lags behind its European counterparts with just 6 W of installed wind capacity per person. The electricity market in France is dominated by the state-owned Electricite de France (EdF) and its nuclear power stations. However, smaller renewable generators are now in theory allowed access to the market and France has transposed the EU renewables directive into national law. The French governement has set a target of generating 10,000 MW of renewable capacity by 2010. The announcement of an increased feed-in tariff and the introduction of 'development zones' (ZDEs) which could allow fast-tracking of planning for wind projects are also expected to boost wind projects. But grid access and adminstrative burdens remain major barriers. In addition, French politicians and local authorities remain committed to nuclear, though encouraged by the European Commission, wind is beginning to gain acceptance; some 325 wind farms (representing 1557 MW of capacity) were approved between February 2004 and January 2005. France is now regarded by the international wind energy sector as a target market. One of France's leading independent wind developers and its only listed wind company, Theolia, is expected to be one of the major beneficiaries of the acceleration of activity in France, though other companies are keen to maximise the opportunities for wind. France currently has only one indigenous manufacturer of wind turbines, but foreign suppliers are winning orders

  18. Denmark Wind Energy Programme

    DEFF Research Database (Denmark)

    Shen, Wen Zhong

    2015-01-01

    In this chapter, a summary of some ongoing wind energy projects in Denmark is given. The research topics comprise computational model development, wind turbine (WT) design, low-noise airfoil and blade design, control device development, wake modelling and wind farm layout optimization....

  19. Wind energy in Mediterranean Basin

    International Nuclear Information System (INIS)

    Gaudiosi, G.

    1991-01-01

    In its examination of wind energy potential in the Mediterranean Basin, this paper provides brief notes on the Basin's geography; indicates power production and demand; describes the area's wind characteristics and wind monitoring activities; illustrates wind velocity distributions; estimates local wind power production potential; reviews the Basin's wind energy marketing situation and each bordering country's wind energy programs; surveys installed wind energy farms; and assesses national research and commercialization efforts

  20. Vertical vector face lift.

    Science.gov (United States)

    Somoano, Brian; Chan, Joanna; Morganroth, Greg

    2011-01-01

    Facial rejuvenation using local anesthesia has evolved in the past decade as a safer option for patients seeking fewer complications and minimal downtime. Mini- and short-scar face lifts using more conservative incision lengths and extent of undermining can be effective in the younger patient with lower face laxity and minimal loose, elastotic neck skin. By incorporating both an anterior and posterior approach and using an incision length between the mini and more traditional face lift, the Vertical Vector Face Lift can achieve longer-lasting and natural results with lesser cost and risk. Submentoplasty and liposuction of the neck and jawline, fundamental components of the vertical vector face lift, act synergistically with superficial musculoaponeurotic system plication to reestablish a more youthful, sculpted cervicomental angle, even in patients with prominent jowls. Dramatic results can be achieved in the right patient by combining with other procedures such as injectable fillers, chin implants, laser resurfacing, or upper and lower blepharoplasties. © 2011 Wiley Periodicals, Inc.

  1. Offshore wind resource estimation for wind energy

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Badger, Merete; Mouche, A.

    2010-01-01

    Satellite remote sensing from active and passive microwave instruments is used to estimate the offshore wind resource in the Northern European Seas in the EU-Norsewind project. The satellite data include 8 years of Envisat ASAR, 10 years of QuikSCAT, and 23 years of SSM/I. The satellite observati......Satellite remote sensing from active and passive microwave instruments is used to estimate the offshore wind resource in the Northern European Seas in the EU-Norsewind project. The satellite data include 8 years of Envisat ASAR, 10 years of QuikSCAT, and 23 years of SSM/I. The satellite...... observations are compared to selected offshore meteorological masts in the Baltic Sea and North Sea. The overall aim of the Norsewind project is a state-of-the-art wind atlas at 100 m height. The satellite winds are all valid at 10 m above sea level. Extrapolation to higher heights is a challenge. Mesoscale...... modeling of the winds at hub height will be compared to data from wind lidars observing at 100 m above sea level. Plans are also to compare mesoscale model results and satellite-based estimates of the offshore wind resource....

  2. Potentials of wind power

    International Nuclear Information System (INIS)

    Bezrukikh, P.P.; Bezrukikh, P.P.

    2000-01-01

    The ecological advantages of the wind power facilities (WPF) are considered. The possibilities of small WPF, generating the capacity from 40 W up to 10 kW, are discussed. The basic technical data on the national and foreign small WPF are presented. The combined wind power systems are considered. Special attention is paid to the most perspective wind-diesel systems, which provide for all possible versions of the electro-power supply. Useful recommendations and information on the wind power engineering are given for those, who decided to build up a wind facility [ru

  3. Visualization of wind farms

    International Nuclear Information System (INIS)

    Pahlke, T.

    1994-01-01

    With the increasing number of wind energy installations the visual impact of single wind turbines or wind parks is a growing problem for landscape preservation, leading to resistance of local authorities and nearby residents against wind energy projects. To increase acceptance and to form a basis for planning considerations, it is necessary to develop instruments for the visualization of planned wind parks, showing their integration in the landscape. Photorealistic montages and computer animation including video sequences may be helpful in 'getting the picture'. (orig.)

  4. Mapping Wind Energy Controversies

    DEFF Research Database (Denmark)

    Munk, Anders Kristian

    As part the Wind2050 project funded by the Danish Council for Strategic Research we have mapped controversies on wind energy as they unfold online. Specifically we have collected two purpose built datasets, a web corpus containing information from 758 wind energy websites in 6 different countries......, and a smaller social media corpus containing information from 14 Danish wind energy pages on Facebook. These datasets have been analyzed to answer questions like: How do wind proponents and opponents organize online? Who are the central actors? And what are their matters of concern? The purpose of this report...

  5. Wind energy applications guide

    Energy Technology Data Exchange (ETDEWEB)

    anon.

    2001-01-01

    The brochure is an introduction to various wind power applications for locations with underdeveloped transmission systems, from remote water pumping to village electrification. It includes an introductory section on wind energy, including wind power basics and system components and then provides examples of applications, including water pumping, stand-alone systems for home and business, systems for community centers, schools, and health clinics, and examples in the industrial area. There is also a page of contacts, plus two specific example applications for a wind-diesel system for a remote station in Antarctica and one on wind-diesel village electrification in Russia.

  6. Wind energy systems

    International Nuclear Information System (INIS)

    Richardson, R.D.; McNerney, G.M.

    1993-01-01

    Wind energy has matured to a level of development where it is ready to become a generally accepted utility generation technology. A brief discussion of this development is presented, and the operating and design principles are discussed. Alternative designs for wind turbines and the tradeoffs that must be considered are briefly compared. Development of a wind energy system and the impacts on the utility network including frequency stability, voltage stability, and power quality are discussed. The assessment of wind power station economics and the key economic factors that determine the economic viability of a wind power plant are presented

  7. Fault Tolerant Wind Farm Control

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2013-01-01

    In the recent years the wind turbine industry has focused on optimizing the cost of energy. One of the important factors in this is to increase reliability of the wind turbines. Advanced fault detection, isolation and accommodation are important tools in this process. Clearly most faults are dealt...... with best at a wind turbine control level. However, some faults are better dealt with at the wind farm control level, if the wind turbine is located in a wind farm. In this paper a benchmark model for fault detection and isolation, and fault tolerant control of wind turbines implemented at the wind farm...... control level is presented. The benchmark model includes a small wind farm of nine wind turbines, based on simple models of the wind turbines as well as the wind and interactions between wind turbines in the wind farm. The model includes wind and power references scenarios as well as three relevant fault...

  8. Wind Tunnel Measurements at LM Wind Power

    DEFF Research Database (Denmark)

    Bertagnolio, Franck

    2012-01-01

    This section presents the results obtained during the experimental campaign that was conducted in the wind tunnel at LM Wind Power in Lunderskov from August 16th to 26th, 2010. The goal of this study is to validate the so-called TNO trailing edge noise model through measurements of the boundary...... layer turbulence characteristics and the far-field noise generated by the acoustic scattering of the turbulent boundary layer vorticies as they convect past the trailing edge. This campaign was conducted with a NACA0015 airfoil section that was placed in the wind tunnel section. It is equipped with high...

  9. Wind energy in Europe

    International Nuclear Information System (INIS)

    Evans, L.C.

    1992-01-01

    Wind energy should be an important part of the energy supply mix, both at home and abroad, to provide cleaner air and a more stable fuel supply. Not only can wind energy contribute to solving complex global issues, it also can provide a large market for American technological leadership. Even though utilities are paying more attention to wind in a number of states, there are no plans for major installations of wind power plants in the United States. At the same time, European nations have developed aggressive wind energy development programs, including both ambitious research and development efforts and market incentives. Many countries recognize the importance of the clean energy provided by wind technology and are taking steps to promote their fledgling domestic industries. The emphasis on market incentives is starting to pay off. In 1991, European utilities and developers installed nearly twice as much wind capacity as Americans did. In 1992 the gap will be even greater. This article reviews aggressive incentives offered by European governments to boost their domestic wind industries at home and abroad in this almost $1 billion per year market. By offering substantial incentives - considerably more than the American Wind Energy Association (AWEA) is proposing - European nations are ensuring dramatic near-term wind energy development and are taking a major step toward dominating the international wind industry of the 21st century

  10. Kansas Wind Energy Consortium

    Energy Technology Data Exchange (ETDEWEB)

    Gruenbacher, Don [Kansas State Univ., Manhattan, KS (United States)

    2015-12-31

    This project addresses both fundamental and applied research problems that will help with problems defined by the DOE “20% Wind by 2030 Report”. In particular, this work focuses on increasing the capacity of small or community wind generation capabilities that would be operated in a distributed generation approach. A consortium (KWEC – Kansas Wind Energy Consortium) of researchers from Kansas State University and Wichita State University aims to dramatically increase the penetration of wind energy via distributed wind power generation. We believe distributed generation through wind power will play a critical role in the ability to reach and extend the renewable energy production targets set by the Department of Energy. KWEC aims to find technical and economic solutions to enable widespread implementation of distributed renewable energy resources that would apply to wind.

  11. Wind Turbine Technologies

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela

    2017-01-01

    The wind turbine technology is a very complex technology involving multidisciplinary and broad technical disciplines such as aerodynamics, mechanics, structure dynamics, meteorology as well as electrical engineering addressing the generation, transmission, and integration of wind turbines...... into the power system. Wind turbine technology has matured over the years and become the most promising and reliable renewable energy technology today. It has moved very fast, since the early 1980s, from wind turbines of a few kilowatts to today’s multimegawatt-sized wind turbines [13]. Besides their size......, the design of wind turbines has changed from being convention driven to being optimized driven within the operating regime and market environment. Wind turbine designs have progressed from fixed speed, passive controlled and with drive trains with gearboxes, to become variable speed, active controlled...

  12. Wind tower service lift

    Science.gov (United States)

    Oliphant, David; Quilter, Jared; Andersen, Todd; Conroy, Thomas

    2011-09-13

    An apparatus used for maintaining a wind tower structure wherein the wind tower structure may have a plurality of legs and may be configured to support a wind turbine above the ground in a better position to interface with winds. The lift structure may be configured for carrying objects and have a guide system and drive system for mechanically communicating with a primary cable, rail or other first elongate member attached to the wind tower structure. The drive system and guide system may transmit forces that move the lift relative to the cable and thereby relative to the wind tower structure. A control interface may be included for controlling the amount and direction of the power into the guide system and drive system thereby causing the guide system and drive system to move the lift relative to said first elongate member such that said lift moves relative to said wind tower structure.

  13. Turning to the wind

    Science.gov (United States)

    Sorensen, B.

    1981-10-01

    Consideration is given the economic and technological aspects of both free-stream (horizontal-axis) and cross-wind (vertical-axis) wind energy conversion systems, with attention to operational devices ranging in rotor diameter from 10 to 40 m and in output from 22 to 630 kW. After a historical survey of wind turbine design and applications development, the near-term technical feasibility and economic attractiveness of combined wind/fossil-fueled generator and wind/hydroelectric systems are assessed. Also presented are estimates of wind energy potential extraction in the U.S. and Denmark, the industrial requirements of large-scale implementation, energy storage possibilities such as pumped hydro and flywheels, and cost comparisons of electrical generation by large and small wind systems, coal-fired plants, and light-water fission reactors.

  14. Wind power takes over

    International Nuclear Information System (INIS)

    2002-01-01

    All over the industrialized world concentrated efforts are being made to make wind turbines cover some of the energy demand in the coming years. There is still a long way to go, however, towards a 'green revolution' as far as energy is concerned, for it is quite futile to use wind power for electric heating. The article deals with some of the advantages and disadvantages of developing wind power. In Norway, for instance, environmentalists fear that wind power plants along the coast may have serious consequences for the stocks of white-tailed eagle and golden eagle. An other factor that delays the large-scale application of wind power in Norway is the low price of electricity. Some experts, however, maintain that wind power may already compete with new hydroelectric power of intermediate cost. The investment costs are expected to go down with one third by 2020, when wind power may be the most competitive energy source to utilize

  15. Wind energy conversion system

    Science.gov (United States)

    Longrigg, Paul

    1987-01-01

    The wind energy conversion system includes a wind machine having a propeller connected to a generator of electric power, the propeller rotating the generator in response to force of an incident wind. The generator converts the power of the wind to electric power for use by an electric load. Circuitry for varying the duty factor of the generator output power is connected between the generator and the load to thereby alter a loading of the generator and the propeller by the electric load. Wind speed is sensed electro-optically to provide data of wind speed upwind of the propeller, to thereby permit tip speed ratio circuitry to operate the power control circuitry and thereby optimize the tip speed ratio by varying the loading of the propeller. Accordingly, the efficiency of the wind energy conversion system is maximized.

  16. Optimality Conditions in Vector Optimization

    CERN Document Server

    Jiménez, Manuel Arana; Lizana, Antonio Rufián

    2011-01-01

    Vector optimization is continuously needed in several science fields, particularly in economy, business, engineering, physics and mathematics. The evolution of these fields depends, in part, on the improvements in vector optimization in mathematical programming. The aim of this Ebook is to present the latest developments in vector optimization. The contributions have been written by some of the most eminent researchers in this field of mathematical programming. The Ebook is considered essential for researchers and students in this field.

  17. Symmetric vectors and algebraic classification

    International Nuclear Information System (INIS)

    Leibowitz, E.

    1980-01-01

    The concept of symmetric vector field in Riemannian manifolds, which arises in the study of relativistic cosmological models, is analyzed. Symmetric vectors are tied up with the algebraic properties of the manifold curvature. A procedure for generating a congruence of symmetric fields out of a given pair is outlined. The case of a three-dimensional manifold of constant curvature (''isotropic universe'') is studied in detail, with all its symmetric vector fields being explicitly constructed

  18. Vector continued fractions using a generalized inverse

    International Nuclear Information System (INIS)

    Haydock, Roger; Nex, C M M; Wexler, Geoffrey

    2004-01-01

    A real vector space combined with an inverse (involution) for vectors is sufficient to define a vector continued fraction whose parameters consist of vector shifts and changes of scale. The choice of sign for different components of the vector inverse permits construction of vector analogues of the Jacobi continued fraction. These vector Jacobi fractions are related to vector and scalar-valued polynomial functions of the vectors, which satisfy recurrence relations similar to those of orthogonal polynomials. The vector Jacobi fraction has strong convergence properties which are demonstrated analytically, and illustrated numerically

  19. Improved Offshore Wind Resource Assessment in Global Climate Stabilization Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Arent, D.; Sullivan, P.; Heimiller, D.; Lopez, A.; Eurek, K.; Badger, J.; Jorgensen, H. E.; Kelly, M.; Clarke, L.; Luckow, P.

    2012-10-01

    This paper introduces a technique for digesting geospatial wind-speed data into areally defined -- country-level, in this case -- wind resource supply curves. We combined gridded wind-vector data for ocean areas with bathymetry maps, country exclusive economic zones, wind turbine power curves, and other datasets and relevant parameters to build supply curves that estimate a country's offshore wind resource defined by resource quality, depth, and distance-from-shore. We include a single set of supply curves -- for a particular assumption set -- and study some implications of including it in a global energy model. We also discuss the importance of downscaling gridded wind vector data to capturing the full resource potential, especially over land areas with complex terrain. This paper includes motivation and background for a statistical downscaling methodology to account for terrain effects with a low computational burden. Finally, we use this forum to sketch a framework for building synthetic electric networks to estimate transmission accessibility of renewable resource sites in remote areas.

  20. Multifrequency spiral vector model for the brushless doubly-fed induction machine

    DEFF Research Database (Denmark)

    Han, Peng; Cheng, Ming; Zhu, Xinkai

    2017-01-01

    This paper presents a multifrequency spiral vector model for both steady-state and dynamic performance analysis of the brushless doubly-fed induction machine (BDFIM) with a nested-loop rotor. Winding function theory is first employed to give a full picture of the inductance characteristics...... analytically, revealing the underlying relationship between harmonic components of stator-rotor mutual inductances and the airgap magnetic field distribution. Different from existing vector models, which only model the fundamental components of mutual inductances, the proposed vector model takes...

  1. Second wind in the offshore wind industry

    International Nuclear Information System (INIS)

    Philippe, Edouard; Neyme, Eric; Deboos, Christophe; Villageois, Jean-Remy; Gouverneur, Philippe; Gerard, Bernard; Fournier, Eric; Petrus, Raymond; Lemarquis, David; Dener, Marc; Bivaud, Jean-Pierre; Lemaire, Etienne; Nielsen, Steffen; Lafon, Xavier; Lagandre, Pierre; Nadai, Alain; Pinot de Villechenon, Edouard; Westhues, Markus; Herpers, Frederick; Bisiaux, Christophe; Sperlich, Miriam; Bales, Vincent; Vandenbroeck, Jan; His, Stephane; Derrey, Thierry; Barakat, Georges; Dakyo, Brayima; Carme, Laurent; Petit, Frederic; Ytournel, Sophie; Westhues, Markus; Diller, Armin; Premont, Antoine de; Ruer, Jacques; Lanoe, Frederic; Declercq, Jan; Holmager, Morten; Fidelin, Daniel; Guillet, Jerome; Dudziak, Gregory; Lapierre, Anne; Couturier, Ludovic; Audineau, Jean-Pierre; Rouaix, Eric; De Roeck, Yann-Herve; Quesnel, Louis; Duguet, Benjamin

    2011-06-01

    After several keynote addresses, this publication contains contributions and Power Point presentations proposed during this conference on the development of offshore wind energy. The successive sessions addressed the following issues: the offshore mass production of electricity (examples of Denmark and Belgium, laying and protecting offshore cables), the space, economic and environmental planning (the Danish experience, the role of the Coastal area integrated management, importance of the public debate, so on), the logistics of port infrastructures (simulation tools, example of Bremerhaven, issues related to project management), innovation at the core of industrial strategies (high power wind turbines, the 6 MW Alstom turbine, chain value and innovation in offshore wind energy, the Vertiwing innovating project of a floating wind turbine, a bench test in Charleston, foundations, gravity base structures, the British experience, the Danish experience), the economic and organisational conditions for development, the validation and certification of technologies

  2. Covariant Lyapunov vectors

    International Nuclear Information System (INIS)

    Ginelli, Francesco; Politi, Antonio; Chaté, Hugues; Livi, Roberto

    2013-01-01

    Recent years have witnessed a growing interest in covariant Lyapunov vectors (CLVs) which span local intrinsic directions in the phase space of chaotic systems. Here, we review the basic results of ergodic theory, with a specific reference to the implications of Oseledets’ theorem for the properties of the CLVs. We then present a detailed description of a ‘dynamical’ algorithm to compute the CLVs and show that it generically converges exponentially in time. We also discuss its numerical performance and compare it with other algorithms presented in the literature. We finally illustrate how CLVs can be used to quantify deviations from hyperbolicity with reference to a dissipative system (a chain of Hénon maps) and a Hamiltonian model (a Fermi–Pasta–Ulam chain). This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Lyapunov analysis: from dynamical systems theory to applications’. (paper)

  3. Covariant Lyapunov vectors

    Science.gov (United States)

    Ginelli, Francesco; Chaté, Hugues; Livi, Roberto; Politi, Antonio

    2013-06-01

    Recent years have witnessed a growing interest in covariant Lyapunov vectors (CLVs) which span local intrinsic directions in the phase space of chaotic systems. Here, we review the basic results of ergodic theory, with a specific reference to the implications of Oseledets’ theorem for the properties of the CLVs. We then present a detailed description of a ‘dynamical’ algorithm to compute the CLVs and show that it generically converges exponentially in time. We also discuss its numerical performance and compare it with other algorithms presented in the literature. We finally illustrate how CLVs can be used to quantify deviations from hyperbolicity with reference to a dissipative system (a chain of Hénon maps) and a Hamiltonian model (a Fermi-Pasta-Ulam chain). This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Lyapunov analysis: from dynamical systems theory to applications’.

  4. Chameleon vector bosons

    International Nuclear Information System (INIS)

    Nelson, Ann E.; Walsh, Jonathan

    2008-01-01

    We show that for a force mediated by a vector particle coupled to a conserved U(1) charge, the apparent range and strength can depend on the size and density of the source, and the proximity to other sources. This chameleon effect is due to screening from a light charged scalar. Such screening can weaken astrophysical constraints on new gauge bosons. As an example we consider the constraints on chameleonic gauged B-L. We show that although Casimir measurements greatly constrain any B-L force much stronger than gravity with range longer than 0.1 μm, there remains an experimental window for a long-range chameleonic B-L force. Such a force could be much stronger than gravity, and long or infinite range in vacuum, but have an effective range near the surface of the earth which is less than a micron.

  5. 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.

  6. Observability of wind power

    International Nuclear Information System (INIS)

    Gonot, J.P.; Fraisse, J.L.

    2009-01-01

    The total installed capacity of wind power grows from a few hundred MW at the beginning of 2005 to 3400 MW at the end of 2008. With such a trend, a total capacity of 7000 MW could be reached by 2010. The natural variability of wind power and the difficulty of its predictability require a change in the traditional way of managing supply/demand balance, day-ahead margins and the control of electrical flows. As a consequence, RTE operators should be informed quickly and reliably of the real time output power of wind farms and of its evolvement some hours or days ahead to ensure the reliability of the French electrical power system. French specificities are that wind farms are largely spread over the territory, that 95 % of wind farms have an output power below 10 MW and that they are connected to the distribution network. In this context, new tools were necessary to acquire as soon as possible data concerning wind power. In two years long, RTE set up an observatory of wind production 'IPES system' enable to get an access to the technical characteristics of the whole wind farms, to observe in real time 75 % of the wind generation and to implement a forecast model related to wind generation. (authors)

  7. Financing wind projects

    International Nuclear Information System (INIS)

    Manson, J.

    2006-01-01

    This presentation reviewed some of the partnership opportunities available from GE Energy. GE Energy's ecomagination commitment has promised to double research investment, make customers true partners and reduce greenhouse gases (GHGs). GE Energy's renewable energy team provides a broad range of financial products, and has recently funded 30 wind farms and 2 large solar projects. The company has a diverse portfolio of technology providers and wind regimes, and is increasing their investment in technology. GE Energy recognizes that the wind industry is growing rapidly and has received increased regulatory support that is backed by strong policy and public support. It is expected that Canada will have 3006 wind projects either planned or under construction by 2007. According to GE Energy, successful wind financing is dependent on the location of the site and its wind resources, as well as on the wind developer's power sales agreement. The success of a wind project is also determined by clear financing goals. Site-specific data is needed to determine the quality of wind resource, and off-site data can also be used to provide validation. Proximity to load centres will help to minimize capital costs. Power sales agreements should be based on the project's realistic net capacity factor as well as on the cost of the turbines. The economics of many wind farms is driven by the size of the turbines used. Public consultations are also needed to ensure the success of wind power projects. It was concluded that a good partner will have staying power in the wind power industry, and will understand the time-lines and needs that are peculiar to wind energy developers. refs., tabs., figs

  8. Windscanner: 3-D wind and turbulence measurements from three steerable doppler lidars

    International Nuclear Information System (INIS)

    Mikkelsen, T; Mann, J; Courtney, M; Sjoeholm, M

    2008-01-01

    At RISOe DTU we has started to build a new-designed laser-based lidar scanning facility for detailed remote measurements of the wind fields engulfing the huge wind turbines of today. Our aim is to measure in real-time 3D wind vector data at several hundred points every second: 1) upstream of the turbine, 2) near the turbine, and 3) in the wakes of the turbine rotors. Our first proto-type Windscanner is now being built from three commercially available Continuous Wave (CW) wind lidars modified with fast adjustable focus length and equipped with 2-D prism-based scan heads, in conjunction with a commercially available pulsed wind lidar for extended vertical profiling range. Design, construction and initial testing of the new 3-D wind lidar scanning facility are described and the functionality of the Windscanner and its potential as a new research facility within the wind energy community is discussed

  9. Simplified Representation of Vector Fields

    NARCIS (Netherlands)

    Telea, Alexandru; Wijk, Jarke J. van

    1999-01-01

    Vector field visualization remains a difficult task. Although many local and global visualization methods for vector fields such as flow data exist, they usually require extensive user experience on setting the visualization parameters in order to produce images communicating the desired insight. We

  10. The Neural Support Vector Machine

    NARCIS (Netherlands)

    Wiering, Marco; van der Ree, Michiel; Embrechts, Mark; Stollenga, Marijn; Meijster, Arnold; Nolte, A; Schomaker, Lambertus

    2013-01-01

    This paper describes a new machine learning algorithm for regression and dimensionality reduction tasks. The Neural Support Vector Machine (NSVM) is a hybrid learning algorithm consisting of neural networks and support vector machines (SVMs). The output of the NSVM is given by SVMs that take a

  11. Estimation of Motion Vector Fields

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    1993-01-01

    This paper presents an approach to the estimation of 2-D motion vector fields from time varying image sequences. We use a piecewise smooth model based on coupled vector/binary Markov random fields. We find the maximum a posteriori solution by simulated annealing. The algorithm generate sample...

  12. Disease Vector Ecology Profile: Peru

    Science.gov (United States)

    1998-12-01

    vector of urban plague in Peru is the Oriental rat flea, Xenopsylla cheopis. The human flea, Pulex irritans, although biologically an inefficient vector...TEL: (215) 688-4400 Peru - 10 Instituto Nacional de Hygiene Lima, Peru Peru – 11 Institutos Nacionales de Salud Departamento de Animales

  13. GPU Accelerated Vector Median Filter

    Science.gov (United States)

    Aras, Rifat; Shen, Yuzhong

    2011-01-01

    Noise reduction is an important step for most image processing tasks. For three channel color images, a widely used technique is vector median filter in which color values of pixels are treated as 3-component vectors. Vector median filters are computationally expensive; for a window size of n x n, each of the n(sup 2) vectors has to be compared with other n(sup 2) - 1 vectors in distances. General purpose computation on graphics processing units (GPUs) is the paradigm of utilizing high-performance many-core GPU architectures for computation tasks that are normally handled by CPUs. In this work. NVIDIA's Compute Unified Device Architecture (CUDA) paradigm is used to accelerate vector median filtering. which has to the best of our knowledge never been done before. The performance of GPU accelerated vector median filter is compared to that of the CPU and MPI-based versions for different image and window sizes, Initial findings of the study showed 100x improvement of performance of vector median filter implementation on GPUs over CPU implementations and further speed-up is expected after more extensive optimizations of the GPU algorithm .

  14. Archimedeanization of ordered vector spaces

    OpenAIRE

    Emelyanov, Eduard Yu.

    2014-01-01

    In the case of an ordered vector space with an order unit, the Archimedeanization method has been developed recently by V.I Paulsen and M. Tomforde. We present a general version of the Archimedeanization which covers arbitrary ordered vector spaces.

  15. Offshore Wind Power Data

    DEFF Research Database (Denmark)

    Cutululis, Nicolaos Antonio; Litong-Palima, Marisciel; Zeni, Lorenzo

    2012-01-01

    Wind power development scenarios are critical when trying to assess the impact of the demonstration at national and European level. The work described in this report had several objectives. The main objective was to prepare and deliver the proper input necessary for assessing the impact of Demo 4...... – Storm management at national and European level. For that, detailed scenarios for offshore wind power development by 2020 and 2030 were required. The aggregation level that is suitable for the analysis to be done is at wind farm level. Therefore, the scenarios for offshore wind power development offer...... details about the wind farms such as: capacity and coordinates. Since the focus is on the impact of storm fronts passage in Northen Europe, the offshore wind power scenarios were estimated only for the countries at North and Baltic Sea. The sources used are public sources, mentioned in the reference list...

  16. Wind farm economics

    International Nuclear Information System (INIS)

    Milborrow, D.J.

    1995-01-01

    The economics of wind energy are changing rapidly, with improvements in machine performance and increases in size both contributing to reduce costs. These trends are examined and future costs assessed. Although the United Kingdom has regions of high wind speed, these are often in difficult terrain and construction costs are often higher than elsewhere in Europe. Nevertheless, wind energy costs are converging with those of the conventional thermal sources. At present, bank loan periods for wind projects are shorter than for thermal plant, which means that energy prices are higher. Ways of overcoming this problem are explored. It is important, also, to examine the value of wind energy. It is argued that wind energy has a higher value than energy from centralized plant, since it is fed into the low-voltage distribution network. (Author)

  17. Wind power in France

    International Nuclear Information System (INIS)

    Tuille, F.; Courtel, J.

    2015-01-01

    After 3 years of steady decreasing, wind power has resumed growth in 2014 in France and the preliminary figures of 2015 confirm this trend. About 1100 MW were installed in 2014 which was almost twice as much as it was installed the year before. This renaissance is mostly due to the implementation of Brottes' law that eases the installations of wind farms by suppressing the wind power development areas (that were interfering with regional wind power schemes) and by suppressing the minimum number of 5 turbines for any new wind farms. Another important incentive measure was the announcement in January 2015 of a new financial support scheme in replacement of the policy of guaranteed purchase price for the electricity produced. In 2014 the total wind power produced in mainland France reached 17 TW which represented 3.1% of the production of electricity. (A.C.)

  18. Extreme winds in Denmark

    DEFF Research Database (Denmark)

    Kristensen, L.; Rathmann, O.; Hansen, S.O.

    2000-01-01

    ), Kegnaes (7 yr), Sprogo (20 yr), and Tystofte (16 yr). The measured data are wind speed, wind direction, temperature and pressure. The wind records are cleaned for terrain effects by means of WASP (Mortensew ct al., Technical Report I-666 (EN), Riso National Laboratory, 1993. Vol. 2. User's Guide......): assuming geostrophic balance, all the wind-velocity data are transformed to friction velocity u(*) and direction at standard conditions by means of the geostrophic drag law for neutral stratification. The basic wind velocity in 30 degrees sectors are obtained through ranking of the largest values...... of the friction velocity pressure pu(*)(2)/2 taken once every two months. The main conclusion is that the basic wind velocity is significantly larger at the west coast of Jutland (25 +/- 1 m/s) than at any of the other sites (22 +/- 1 m/s). These results are in agreement with those obtained by Jensen and Franck...

  19. Wind turbine state estimation

    DEFF Research Database (Denmark)

    Knudsen, Torben

    2014-01-01

    the results using full-scale wind turbine data. The previously developed methods were based on extended Kalman filtering. This method has several drawback compared to unscented Kalman filtering which has therefore been developed. The unscented Kalman filter was first tested on linear and non-linear test cases......Dynamic inflow is an effect which is normally not included in the models used for wind turbine control design. Therefore, potential improvement from including this effect exists. The objective in this project is to improve the methods previously developed for this and especially to verify...... which was successful. Then the estimation of a wind turbine state including dynamic inflow was tested on a simulated NREL 5MW turbine was performed. This worked perfectly with wind speeds from low to nominal wind speed as the output prediction errors where white. In high wind where the pitch actuator...

  20. Noise from wind turbines

    International Nuclear Information System (INIS)

    Andersen, B.; Jakobsen, J.

    1992-11-01

    Based on a previous project concerning the calculation of the amount of noise emanating from wind turbine arrays, this one examines the subject further by investigating whether there could be significant differences in the amount of noise made by individual wind turbines in an array, and whether the noise is transmitted in varying directions - so that when it is carried in the same direction as the wind blows it would appear to be louder. The aim was also to determine whether the previously used method of calculation lacked precision. It was found that differences in noise niveaux related to individual wind turbines were insignificant and that noise was not so loud when it was not borne in the direction of the wind. It was necessary to change the method of calculation as reckoning should include the influence of the terrain, wind velocity and distance. The measuring and calculation methods are exemplified and the resulting measurements are presented in detail. (AB)

  1. Wind turbine pitch optimization

    DEFF Research Database (Denmark)

    Biegel, Benjamin; Juelsgaard, Morten; Stoustrup, Jakob

    2011-01-01

    We consider a static wind model for a three-bladed, horizontal-axis, pitch-controlled wind turbine. When placed in a wind field, the turbine experiences several mechanical loads, which generate power but also create structural fatigue. We address the problem of finding blade pitch profiles......% compared to any constant pitch profile while sacrificing at most 7% of the maximum attainable output power. Using iterative learning, we show that very similar performance can be achieved by using only load measurements, with no knowledge of the wind field or wind turbine model....... for maximizing power production while simultaneously minimizing fatigue loads. In this paper, we show how this problem can be approximately solved using convex optimization. When there is full knowledge of the wind field, numerical simulations show that force and torque RMS variation can be reduced by over 96...

  2. SERI Wind Energy Program

    Energy Technology Data Exchange (ETDEWEB)

    Noun, R. J.

    1983-06-01

    The SERI Wind Energy Program manages the areas or innovative research, wind systems analysis, and environmental compatibility for the U.S. Department of Energy. Since 1978, SERI wind program staff have conducted in-house aerodynamic and engineering analyses of novel concepts for wind energy conversion and have managed over 20 subcontracts to determine technical feasibility; the most promising of these concepts is the passive blade cyclic pitch control project. In the area of systems analysis, the SERI program has analyzed the impact of intermittent generation on the reliability of electric utility systems using standard utility planning models. SERI has also conducted methodology assessments. Environmental issues related to television interference and acoustic noise from large wind turbines have been addressed. SERI has identified the causes, effects, and potential control of acoustic noise emissions from large wind turbines.

  3. Wind Energy Systems

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Ma, Ke

    2017-01-01

    Wind power now represents a major and growing source of renewable energy. Large wind turbines (with capacities of up to 6-8 MW) are widely installed in power distribution networks. Increasing numbers of onshore and offshore wind farms, acting as power plants, are connected directly to power...... transmission networks at the scale of hundreds of megawatts. As its level of grid penetration has begun to increase dramatically, wind power is starting to have a significant impact on the operation of the modern grid system. Advanced power electronics technologies are being introduced to improve...... the characteristics of the wind turbines, and make them more suitable for integration into the power grid. Meanwhile, there are some emerging challenges that still need to be addressed. This paper provides an overview and discusses some trends in the power electronics technologies used for wind power generation...

  4. Danish Wind Power

    DEFF Research Database (Denmark)

    Lund, Henrik; Hvelplund, Frede; Østergaard, Poul Alberg

    In a normal wind year, Danish wind turbines generate the equivalent of approx. 20 percent of the Danish electricity demand. This paper argues that only approx. 1 percent of the wind power production is exported. The rest is used to meet domestic Danish electricity demands. The cost of wind power......, a study made by the Danish think tank CEPOS claimed the opposite, i.e. that most of the Danish wind power has been exported in recent years. However, this claim is based on an incorrect interpretation of statistics and a lack of understanding of how the international electricity markets operate...... is paid solely by the electricity consumers and the net influence on consumer prices was as low as 1-3 percent on average in the period 2004-2008. In 2008, the net influence even decreased the average consumer price, although only slightly. In Denmark, 20 percent wind power is integrated by using both...

  5. Wind Turbines Wake Aerodynamics

    DEFF Research Database (Denmark)

    Vermeer, L.; Sørensen, Jens Nørkær; Crespo, A.

    2003-01-01

    The aerodynamics of horizontal axis wind turbine wakes is studied. The contents is directed towards the physics of power extraction by wind turbines and reviews both the near and the far wake region. For the near wake, the survey is restricted to uniform, steady and parallel flow conditions......, thereby excluding wind shear, wind speed and rotor setting changes and yawed conditions. The emphasis is put on measurements in controlled conditions.For the far wake, the survey focusses on both single turbines and wind farm effects, and the experimental and numerical work are reviewed; the main interest...... is to study how the far wake decays downstream, in order to estimate the effect produced in downstream turbines.The article is further restricted to horizontal axis wind turbines and excludes all other types of turbines....

  6. 77 FR 29633 - Alta Wind VII, LLC, Alta Wind IX, LLC, Alta Wind X, LLC, Alta Wind XI, LLC, Alta Wind XII, LLC...

    Science.gov (United States)

    2012-05-18

    ..., Alta Wind XIV, LLC, Alta Wind XV, LLC, Alta Windpower Development, LLC, TGP Development Company, LLC... XIII, LLC, Alta Wind XIV, LLC, Alta Wind XV, LLC, Alta Windpower Development, LLC, and TGP Development...

  7. Transcriptional Silencing of Retroviral Vectors

    DEFF Research Database (Denmark)

    Lund, Anders Henrik; Duch, M.; Pedersen, F.S.

    1996-01-01

    Although retroviral vector systems have been found to efficiently transduce a variety of cell types in vitro, the use of vectors based on murine leukemia virus in preclinical models of somatic gene therapy has led to the identification of transcriptional silencing in vivo as an important problem....... Extinction of long-term vector expression has been observed after implantation of transduced hematopoietic cells as well as fibroblasts, myoblasts and hepatocytes. Here we review the influence of vector structure, integration site and cell type on transcriptional silencing. While down-regulation of proviral...... transcription is known from a number of cellular and animal models, major insight has been gained from studies in the germ line and embryonal cells of the mouse. Key elements for the transfer and expression of retroviral vectors, such as the viral transcriptional enhancer and the binding site for the t...

  8. Vector superconductivity in cosmic strings

    International Nuclear Information System (INIS)

    Dvali, G.R.; Mahajan, S.M.

    1992-03-01

    We argue that in most realistic cases, the usual Witten-type bosonic superconductivity of the cosmic string is automatically (independent of the existence of superconducting currents) accompanied by the condensation of charged gauge vector bosons in the core giving rise to a new vector type superconductivity. The value of the charged vector condensate is related with the charged scalar expectation value, and vanishes only if the latter goes to zero. The mechanism for the proposed vector superconductivity, differing fundamentally from those in the literature, is delineated using the simplest realistic example of the two Higgs doublet standard model interacting with the extra cosmic string. It is shown that for a wide range of parameters, for which the string becomes scalarly superconducting, W boson condensates (the sources of vector superconductivity) are necessarily excited. (author). 14 refs

  9. Enabling Wind Power Nationwide

    Energy Technology Data Exchange (ETDEWEB)

    Jose Zayas, Michael Derby, Patrick Gilman and Shreyas Ananthan,

    2015-05-01

    Leveraging this experience, the U.S. Department of Energy’s (DOE’s) Wind and Water Power Technologies Office has evaluated the potential for wind power to generate electricity in all 50 states. This report analyzes and quantifies the geographic expansion that could be enabled by accessing higher above ground heights for wind turbines and considers the means by which this new potential could be responsibly developed.

  10. Wind and Yaw correlation

    DEFF Research Database (Denmark)

    Kock, Carsten Weber; Vesth, Allan

    The report describes measurements carried out on a given wind turbine. A comparison between wind speed on the metmast and Nacelle Windspeed are made and the results are presented on graphs and in a table. The data used for the comparison are identical with the data used for the Risø-I-3246(EN......) power curve report. The measurements are carried out in accordance to Ref. [1] and the wind and yaw correlation is analyzed in accordance to Ref. [2]....

  11. Current issues concerning the representativeness and utility of cloud drift winds in mesoscale meteorology

    Science.gov (United States)

    Koch, Steven E.

    1985-01-01

    High-resolution cloud motion wind (CMW) data sets obtained from geostationary satellites for approximately the past decade have been used for the purpose of estimating mesoscale wind fields in various research studies. Yet there remains much controversy surrounding the proper interpretation and use of the resultant wind vector and kinematic fields. This paper is concerned with: (1) how representative are cloud draft winds of actual ambient air motions; and (2) what is the degree of practical usefulness of CMW fields for both mesoscale analysis and as input to numerical weather prediction models.

  12. Annual and interannual variability of scatterometer ocean surface wind over the South China Sea

    DEFF Research Database (Denmark)

    Zhang, GS; Xu, Q.; Gong, Z.

    2014-01-01

    To investigate the annual and interannual variability of ocean surface wind over the South China Sea (SCS), the vector empirical orthogonal function (VEOF) method and the Hilbert-Huang transform (HHT) method were employed to analyze a set of combined satellite scatterometer wind data during...... the period from December 1992 to October 2009. The merged wind data were generated from European Remote Sensing Satellite (ERS)-1/2 Scatterometer, NASA Scatterometer (NSCAT) and NASA's Quick Scatterometer (QuikSCAT) wind products. The first VEOF mode corresponds to a winter-summer mode which accounts for 87...

  13. Auctioning wind power sites when environmental quality matters

    International Nuclear Information System (INIS)

    Ciaccia, Gervasio; Doni, Nicola; Fontini, Fulvio

    2010-01-01

    In this work, we propose an index that allows a public authority to order different projects for the construction of onshore wind energy plants and that explicitly takes into account their environmental quality. Wind farm projects are defined as vectors of four attributes: the technical properties of each project, its social impact, its environmental impact, and the share of earnings that proponents offer to the collectivity in compensation for the negative externalities of the wind plant. We define an absolute index that allows the ordering of different proposals and evaluation of the acceptability of each project, providing the monetary value of each point and inducing a truthful revelation of firms' private information. Moreover, we calibrate the index on the basis of data referring to wind plants in Southern Italy and derive the corresponding iso-scoring curves. (author)

  14. Classification of Solar Wind With Machine Learning

    Science.gov (United States)

    Camporeale, Enrico; Carè, Algo; Borovsky, Joseph E.

    2017-11-01

    We present a four-category classification algorithm for the solar wind, based on Gaussian Process. The four categories are the ones previously adopted in Xu and Borovsky (2015): ejecta, coronal hole origin plasma, streamer belt origin plasma, and sector reversal origin plasma. The algorithm is trained and tested on a labeled portion of the OMNI data set. It uses seven inputs: the solar wind speed Vsw, the temperature standard deviation σT, the sunspot number R, the F10.7 index, the Alfven speed vA, the proton specific entropy Sp, and the proton temperature Tp compared to a velocity-dependent expected temperature. The output of the Gaussian Process classifier is a four-element vector containing the probabilities that an event (one reading from the hourly averaged OMNI database) belongs to each category. The probabilistic nature of the prediction allows for a more informative and flexible interpretation of the results, for instance, being able to classify events as "undecided." The new method has a median accuracy larger than 90% for all categories, even using a small set of data for training. The Receiver Operating Characteristic curve and the reliability diagram also demonstrate the excellent quality of this new method. Finally, we use the algorithm to classify a large portion of the OMNI data set, and we present for the first time transition probabilities between different solar wind categories. Such probabilities represent the "climatological" statistics that determine the solar wind baseline.

  15. Analytic Theory of Wind-Driven Sea

    Science.gov (United States)

    Zakharov, V. E.

    2016-12-01

    Wind-driven sea is characterized by the spatial energy spectrum E(k), k - is a wave vector. The spectrum has a sharp maximum at k ≈ kp is defined by the wind velocity U and by the "wave-age" - degree of the sea development. For the"well developed sea" kp ≈ g/U2. For a typical value of U ≈ 15 m/sec (moderate gale) λp = 2π/kp≈ 100m. The minimalscale λcap λ > λcrit, λcrit ≈ 10-2λp. This range of scales contains more then 90% of wave energy. Wave dissipation in this range is negligibly small.2. Region of energy dissipation λ 5m/sec, the sea is also smooth and the dissipation is provided by transformation of gravity waves to capillary waves. For strong winds the dissipation is realized due to wave breaking. In this case one can observe the range of scales 5•10-2m method of theoretical physics. The statistical description of this part of the wind driven sea is described by the Hasselmann kinetic equation for the energy spectrum. This kinetic equation has a rich family of exact solutions, both stationary and time-dependent. It allows a comfortable and fast numerical simulations. Putting together results of the analytical theory and numerical simulations of waves it is possible to explain a bulk of facts, accumulated by experimentalists for decades.

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

    CERN Document Server

    Quang, Nguyen Phung

    2008-01-01

    Covers the area of vector control of 3-phase AC machines, in particular induction motors with squirrel-cage rotor, permanent excited synchronous motors and doubly-fed induction machines. This title summarizes the basic structure of a field-oriented controlled 3-phase AC drive and grid voltage orientated controlled wind power plant.

  17. Coastal and rain-induced wind variability depicted by scatterometers

    Science.gov (United States)

    Portabella, M.; Lin, W.; Stoffelen, A.; Turiel, A.; Verhoef, A.; Verspeek, J.; Ballabrera, J.; Vogelzang, J.

    2012-04-01

    A detailed knowledge of local wind variability near the shore is very important since it strongly affects the weather and microclimate in coastal regions. Since coastal areas are densely populated and most activity at sea occurs near the shore, sea-surface wind field information is important for a number of applications. In the vicinity of land sea-breeze, wave fetch, katabatic and current effects are more likely than in the open ocean, thus enhancing air-sea interaction. Also very relevant for air-sea interaction are the rain-induced phenomena, such as downbursts and convergence. Relatively cold and dry air is effectively transported to the ocean surface and surface winds are enhanced. In general, both coastal and rain-induced wind variability are poorly resolved by Numerical Weather Prediction (NWP) models. Satellite real aperture radars (i.e., scatterometers) are known to provide accurate mesoscale (25-50 km resolution) sea surface wind field information used in a wide variety of applications. Nowadays, there are two operating scatterometers in orbit, i.e., the C-band Advanced Scatterometer (ASCAT) onboard Metop-A and the Ku-band scatterometer (OSCAT) onboard Oceansat-2. The EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI SAF) delivers several ASCAT level 2 wind products with 25 km and 12.5 km Wind Vector Cell (WVC) spacing, including a pre-operational coastal wind product as well as an OSCAT level 2 wind product with 50 km spacing in development status. Rain is known to both attenuate and scatter the microwave signal. In addition, there is a "splashing" effect. The roughness of the sea surface is increased because of splashing due to rain drops. The so-called "rain contamination" is larger for Ku-band scatterometer systems than for C-band systems. Moreover, the associated downdrafts lead to variable wind speeds and directions, further complicating the wind retrieval. The C-band ASCAT high resolution wind processing is validated under rainy

  18. 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.

  19. Wind on the moors

    International Nuclear Information System (INIS)

    Martin, S.

    1992-01-01

    A local town councillor describes the setting up of a wind farm in the south Pennines which plans to sell electricity to the local electricity suppliers. The Coal Clough wind farm will generate sufficient electricity to meet the average demand of 7,500 households and will be managed by a consortium known as Wind Resources Limited linking the construction company and the utilities aiming to buy the electricity produced. While wind power offers many environmental advantages over other means of power generation, local opposition was strong on the basis of the noise produced and clearly visible structures in an area designated as being of outstanding natural beauty. (UK)

  20. Vertical axis wind turbine

    International Nuclear Information System (INIS)

    Obretenov, V.; Tsalov, T.; Chakarov, T.

    2012-01-01

    In recent years, the interest in wind turbines with vertical axis noticeably increased. They have some important advantages: low cost, relatively simple structure, reliable packaging system of wind aggregate long period during which require no maintenance, low noise, independence of wind direction, etc.. The relatively low efficiency, however, makes them applicable mainly for small facilities. The work presents a methodology and software for approximately aerodynamic design of wind turbines of this type, and also analyzed the possibility of improving the efficiency of their workflow

  1. Microsystem Aeromechanics Wind Tunnel

    Data.gov (United States)

    Federal Laboratory Consortium — The Microsystem Aeromechanics Wind Tunnel advances the study of fundamental flow physics relevant to micro air vehicle (MAV) flight and assesses vehicle performance...

  2. Winds of change

    International Nuclear Information System (INIS)

    Palmer, C.; Short, L.

    1998-01-01

    The British countryside is oversubscribed with multiple and often irreconcilable demands. The siting of wind turbines is but one facet of this situation. While the problems of these demands are widely recognised, there is little understanding or agreement on how to resolve them. The 1996 Future Landscape: New Partnerships was an attempt to address this challenge. The use of wind energy as a case study initiated a partnership between contemporary artists and the wind energy industry. It became clear that artists have an important role to play in creating new ways of seeing that will establish wind turbines as new icons for a sustainable future. (Author)

  3. Could wind replace nuclear?

    International Nuclear Information System (INIS)

    2017-01-01

    This article aims at assessing the situation produced by a total replacement of nuclear energy by wind energy, while facing consumption demand at any moment, notably in December. The authors indicate the evolution of the French energy mix during December 2016, and the evolution of the rate between wind energy production and the sum of nuclear and wind energy production during the same month, and then give briefly some elements regarding necessary investments in wind energy to wholly replace nuclear energy. According to them, such a replacement would be ruinous

  4. Climate Wind Power Resources

    Directory of Open Access Journals (Sweden)

    Nana M. Berdzenishvili

    2013-01-01

    Full Text Available Georgia as a whole is characterized by rather rich solar energy resources, which allows to construct alternative power stations in the close proximity to traditional power plants. In this case the use of solar energy is meant. Georgia is divided into 5 zones based on the assessment of wind power resources. The selection of these zones is based on the index of average annual wind speed in the examined area, V> 3 m / s and V> 5 m / s wind speed by the summing duration in the course of the year and V = 0. . . 2 m / s of passive wind by total and continuous duration of these indices per hour.

  5. Wind Energy Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Laurie, Carol

    2017-02-01

    This book takes readers inside the places where daily discoveries shape the next generation of wind power systems. Energy Department laboratory facilities span the United States and offer wind research capabilities to meet industry needs. The facilities described in this book make it possible for industry players to increase reliability, improve efficiency, and reduce the cost of wind energy -- one discovery at a time. Whether you require blade testing or resource characterization, grid integration or high-performance computing, Department of Energy laboratory facilities offer a variety of capabilities to meet your wind research needs.

  6. Vertical axis wind turbines

    Science.gov (United States)

    Krivcov, Vladimir [Miass, RU; Krivospitski, Vladimir [Miass, RU; Maksimov, Vasili [Miass, RU; Halstead, Richard [Rohnert Park, CA; Grahov, Jurij [Miass, RU

    2011-03-08

    A vertical axis wind turbine is described. The wind turbine can include a top ring, a middle ring and a lower ring, wherein a plurality of vertical airfoils are disposed between the rings. For example, three vertical airfoils can be attached between the upper ring and the middle ring. In addition, three more vertical airfoils can be attached between the lower ring and the middle ring. When wind contacts the vertically arranged airfoils the rings begin to spin. By connecting the rings to a center pole which spins an alternator, electricity can be generated from wind.

  7. Wind Power in Georgia

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-11-01

    Georgia has good wind power potential. Preliminary analyses show that the technical wind power potential in Georgia is good. Meteorological data shows that Georgia has four main areas in Georgia with annual average wind speeds of over 6 m/s and two main areas with 5-6 m/s at 80m. The most promising areas are the high mountain zone of the Great Caucasus, The Kura river valley, The South-Georgian highland and the Southern part of the Georgian Black Sea coast. Czech company Wind Energy Invest has recently signed a Memorandum of Understanding with Georgian authorities for development of the first wind farm in Georgia, a 50MW wind park in Paravani, Southern Georgia, to be completed in 2014. Annual generation is estimated to 170.00 GWh and the investment estimated to 101 million US$. Wind power is suited to balance hydropower in the Georgian electricity sector Electricity generation in Georgia is dominated by hydro power, constituting 88% of total generation in 2009. Limited storage capacity and significant spring and summer peaks in river flows result in an uneven annual generation profile and winter time shortages that are covered by three gas power plants. Wind power is a carbon-free energy source well suited to balance hydropower, as it is available (often strongest) in the winter and can be exported when there is a surplus. Another advantage with wind power is the lead time for the projects; the time from site selection to operation for a wind power park (approximately 2.5 years) is much shorter than for hydro power (often 6-8 years). There is no support system or scheme for renewable sources in Georgia, so wind power has to compete directly with other energy sources and is in most cases more expensive to build than hydro power. In a country and region with rapidly increasing energy demands, the factors described above nevertheless indicate that there is a commercial niche and a role to play for Georgian wind power. Skra: An example of a wind power development

  8. Wind Power Today: (2002) Wind Energy Research Highlights

    Energy Technology Data Exchange (ETDEWEB)

    2003-05-01

    Wind Power Today is an annual publication that provides an overview of the wind research conducted under the U.S. Department of Energy's Wind and Hydropower Technologies Program. The purpose of Wind Power Today is to show how DOE supports wind turbine research and deployment in hopes of furthering the advancement of wind technologies that produce clean, low-cost, reliable energy. Content objectives include: educate readers about the advantages and potential for widespread deployment of wind energy; explain the program's objectives and goals; describe the program's accomplishments in research and application; examine the barriers to widespread deployment; describe the benefits of continued research and development; facilitate technology transfer; and attract cooperative wind energy projects with industry. This 2002 edition of Wind Power Today also includes discussions about wind industry growth in 2002, how DOE is taking advantage of low wind speed regions through advancing technology, and distributed applications for small wind turbines.

  9. Sensing the wind profile

    Energy Technology Data Exchange (ETDEWEB)

    Pena, A.

    2009-03-15

    This thesis consists of two parts. The first is a synopsis of the theoretical progress of the study that is based on a number of journal papers. The papers, which constitute the second part of the report, aim to analyze, measure, and model the wind prole in and beyond the surface layer by combining observations from cup anemometers with lidars. The lidar is necessary to extend the measurements on masts at the Horns Rev offshore wind farm and over at land at Hoevsoere, Denmark. Both sensing techniques show a high degree of agreement for wind speed measurements performed at either sites. The wind speed measurements are averaged for several stability conditions and compare well with the surface-layer wind profile. At Hoevsoere, it is sufficient to scale the wind speed with the surface friction velocity, whereas at Horns Rev a new scaling is added, due to the variant roughness length. This new scaling is coupled to wind prole models derived for flow over the sea and tested against the wind proles up to 160 m at Horns Rev. The models, which account for the boundary-layer height in stable conditions, show better agreement with the measurements than compared to the traditional theory. Mixing-length parameterizations for the neutral wind prole compare well with length-scale measurements up to 300 m at Hoevsoere and 950 m at Leipzig. The mixing-length-derived wind proles strongly deviate from the logarithmic wind prole, but agree better with the wind speed measurements. The length-scale measurements are compared to the length scale derived from a spectral analysis performed up to 160 m at Hoevsoere showing high agreement. Mixing-length parameterizations are corrected to account for stability and used to derive wind prole models. These compared better to wind speed measurements up to 300 m at Hoevsoere than the surface-layer wind prole. The boundary-layer height is derived in nearneutral and stable conditions based on turbulent momentum uxes only and in unstable conditions

  10. Wind energy - an overview

    International Nuclear Information System (INIS)

    Rangi, R.; Oprisan, M.

    1998-01-01

    The current status of wind technology developments in Canada and around the world was reviewed. Information regarding the level of wind turbine deployment was presented. It was shown that significant effort has been made on the national and international level to increase the capacity of this clean, non-polluting form of energy. Wind energy has become competitive with conventional sources of electricity due to lower cost, higher efficiency and improved reliability of generating equipment. The advantages and disadvantages of wind electricity generating systems and the economics and atmospheric emissions of the systems were described. At present, there is about 23 MW of wind energy generating capacity installed in Canada, but the potential is very large. It was suggested that wind energy could supply as much as 60 per cent of Canada's electricity needs if only one per cent of the land with 'good winds' were covered by wind turbines. Recently, the Canadian government has provided an accelerated capital cost allowance for certain types of renewable energies under the Income Tax Act, and the flow-through share financing legislation to include intangible expenses in certain renewable energy projects has been extended. Besides the support provided to the private sector through tax advantages, the Government also supports renewable energy development by purchasing 'green' energy for its own buildings across the country, and by funding a research and development program to identify and promote application of wind energy technologies, improve its cost effectiveness, and support Canadian wind energy industries with technology development to enhance their competitiveness at home and abroad. Details of the Wind Energy Program, operated by Natural Resources Canada, are described. 3 tabs., 5 figs

  11. A short note on the paper of Liu et al. (2012). A relative Lempel-Ziv complexity: Application to comparing biological sequences. Chemical Physics Letters, volume 530, 19 March 2012, pages 107-112

    Science.gov (United States)

    Arit, Turkan; Keskin, Burak; Firuzan, Esin; Cavas, Cagin Kandemir; Liu, Liwei; Cavas, Levent

    2018-04-01

    The report entitled "L. Liu, D. Li, F. Bai, A relative Lempel-Ziv complexity: Application to comparing biological sequences, Chem. Phys. Lett. 530 (2012) 107-112" mentions on the powerful construction of phylogenetic trees based on Lempel-Ziv algorithm. On the other hand, the method explained in the paper does not give promising result on the data set on invasive Caulerpa taxifolia in the Mediterranean Sea. The phylogenetic trees are obtained by the proposed method of the aforementioned paper in this short note.

  12. Revisiting syntactic development in deaf and hearing children from a dependency approach. Comment on "Dependency distance: a new perspective on syntactic patterns in natural languages" by Haitao Liu et al.

    Science.gov (United States)

    Yan, Jingqi

    2017-07-01

    Linguists are always endeavoring to discover universal rules to explain the language phenomena and interrelations [1]. Through a handful of corpus-based studies and a vast body of supporting evidence from psychological experiments, Liu, Xu and Liang [2] arrive at a conclusion on a general tendency toward dependency distance minimization (DDM) and relate this linguistic universal to the constraints of memory. Dependency distance (DD) is hereby introduced as a linguistic property, with quantitative features of frequency, and profound cognitive grounding as well. However, since the authors do not include language development, in this comment, I would like to discuss some future prospects from this perspective.

  13. Enhancing poxvirus vectors vaccine immunogenicity.

    Science.gov (United States)

    García-Arriaza, Juan; Esteban, Mariano

    2014-01-01

    Attenuated recombinant poxvirus vectors expressing heterologous antigens from pathogens are currently at various stages in clinical trials with the aim to establish their efficacy. This is because these vectors have shown excellent safety profiles, significant immunogenicity against foreign expressed antigens and are able to induce protective immune responses. In view of the limited efficacy triggered by some poxvirus strains used in clinical trials (i.e, ALVAC in the RV144 phase III clinical trial for HIV), and of the restrictive replication capacity of the highly attenuated vectors like MVA and NYVAC, there is a consensus that further improvements of these vectors should be pursuit. In this review we considered several strategies that are currently being implemented, as well as new approaches, to improve the immunogenicity of the poxvirus vectors. This includes heterologous prime/boost protocols, use of co-stimulatory molecules, deletion of viral immunomodulatory genes still present in the poxvirus genome, enhancing virus promoter strength, enhancing vector replication capacity, optimizing expression of foreign heterologous sequences, and the combined use of adjuvants. An optimized poxvirus vector triggering long-lasting immunity with a high protective efficacy against a selective disease should be sought.

  14. Chikungunya Virus–Vector Interactions

    Science.gov (United States)

    Coffey, Lark L.; Failloux, Anna-Bella; Weaver, Scott C.

    2014-01-01

    Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that causes chikungunya fever, a severe, debilitating disease that often produces chronic arthralgia. Since 2004, CHIKV has emerged in Africa, Indian Ocean islands, Asia, Europe, and the Americas, causing millions of human infections. Central to understanding CHIKV emergence is knowledge of the natural ecology of transmission and vector infection dynamics. This review presents current understanding of CHIKV infection dynamics in mosquito vectors and its relationship to human disease emergence. The following topics are reviewed: CHIKV infection and vector life history traits including transmission cycles, genetic origins, distribution, emergence and spread, dispersal, vector competence, vector immunity and microbial interactions, and co-infection by CHIKV and other arboviruses. The genetics of vector susceptibility and host range changes, population heterogeneity and selection for the fittest viral genomes, dual host cycling and its impact on CHIKV adaptation, viral bottlenecks and intrahost diversity, and adaptive constraints on CHIKV evolution are also discussed. The potential for CHIKV re-emergence and expansion into new areas and prospects for prevention via vector control are also briefly reviewed. PMID:25421891

  15. Chikungunya Virus–Vector Interactions

    Directory of Open Access Journals (Sweden)

    Lark L. Coffey

    2014-11-01

    Full Text Available Chikungunya virus (CHIKV is a mosquito-borne alphavirus that causes chikungunya fever, a severe, debilitating disease that often produces chronic arthralgia. Since 2004, CHIKV has emerged in Africa, Indian Ocean islands, Asia, Europe, and the Americas, causing millions of human infections. Central to understanding CHIKV emergence is knowledge of the natural ecology of transmission and vector infection dynamics. This review presents current understanding of CHIKV infection dynamics in mosquito vectors and its relationship to human disease emergence. The following topics are reviewed: CHIKV infection and vector life history traits including transmission cycles, genetic origins, distribution, emergence and spread, dispersal, vector competence, vector immunity and microbial interactions, and co-infection by CHIKV and other arboviruses. The genetics of vector susceptibility and host range changes, population heterogeneity and selection for the fittest viral genomes, dual host cycling and its impact on CHIKV adaptation, viral bottlenecks and intrahost diversity, and adaptive constraints on CHIKV evolution are also discussed. The potential for CHIKV re-emergence and expansion into new areas and prospects for prevention via vector control are also briefly reviewed.

  16. Violation of vector dominance in the vector manifestation

    International Nuclear Information System (INIS)

    Sasaki, Chihiro

    2003-01-01

    The vector manifestation (VM) is a new pattern for realizing the chiral symmetry in QCD. In the VM, the massless vector meson becomes the chiral partner of pion at the critical point, in contrast with the restoration based on the linear sigma model. Including the intrinsic temperature dependences of the parameters of the hidden local symmetry (HLS) Lagrangian determined from the underlying QCD through the Wilsonian matching together with the hadronic thermal corrections, we present a new prediction of the VM on the direct photon-π-π coupling which measures the validity of the vector dominance (VD) of the electromagnetic form factor of the pion. We find that the VD is largely violated at the critical temperature, which indicates that the assumption of the VD made in several analysis on the dilepton spectra in hot matter may need to be weakened for consistently including the effect of the dropping mass of the vector meson. (author)

  17. Wind power integration : From individual wind turbine to wind park as a power plant

    NARCIS (Netherlands)

    Zhou, Y.

    2009-01-01

    As power capacities of single wind turbine, single wind park and total wind power installation are continuously increasing, the wind power begins to challenge the safety operation of the power system. This thesis focuses on the grid integration aspects such as the dynamic behaviours of wind power

  18. Comparison of ERS-1 scatterometer and Florida State University tropical winds

    Science.gov (United States)

    Legler, David M.; Obrien, James J.

    1994-01-01

    Monthly mean winds from the CMODFD (wind vector data set) ERS-1 Active Microwave Instrument (AMI) scatterometer are evaluated by comparing them to monthly mean tropical Pacific and Indian Ocean wind analyses based on in-situ data. The FSU (an observation based set of fields) winds agree qualitatively with the ERS-1 winds. Magnitudes of the vector differences are 2 to 4 m/s. Evident in the ERS-1 fields are north-south oriented bands which coincide with orbital sampling swaths. These bands are more evident in the curl maps of the mean monthly wind fields. Suitability of the ERS-1 monthly mean wind fields for ocean modeling is evaluated through a comparison of results from a model of the tropical Pacific forced by both FSU and ERS-1 wind fields. Model responses in the eastern equatorial Pacific are similar, and both track variability in the observed sea level. However, ERS-1 wind results do not correlate as well to the monthly variations in the sea level data.

  19. Wind speed dynamical model in a wind farm

    DEFF Research Database (Denmark)

    Soleimanzadeh, Maryam; Wisniewski, Rafal

    2010-01-01

    , the dynamic model for wind flow will be established. The state space variables are determined based on a fine mesh defined for the farm. The end goal of this method is to assist the development of a dynamical model of a wind farm that can be engaged for better wind farm control strategies.......This paper presents a model for wind speed in a wind farm. The basic purpose of the paper is to calculate approximately the wind speed in the vicinity of each wind turbine in a farm. In this regard the governing equations of flow will be solved for the whole wind farm. In ideal circumstances...

  20. Vector calculation of particle code

    International Nuclear Information System (INIS)

    Nishiguchi, A.; Yabe, T.; Orii, S.

    1985-01-01

    The development of vector computer requires the modification of the algorithm into a suitable form for vector calculation. Among many algorithms, the particle code is a typical example which has suffered a damage in the calculation on supercomputer owing to its possibility of recurrent data access in collecting cell-wise quantities from particle's quartities. In this article, we report a new method to liberate the particle code from recurrent calculations. It should be noticed, however, that the method may depend on the architecture of supercomputer, and works well on FACOM VP-100 and VP-200: the indirect data accessing must be vectorized and its speed should be fast. (Mori, K.)

  1. Synthetic Aperture Vector Flow Imaging

    DEFF Research Database (Denmark)

    Oddershede, Niels

    2008-01-01

    of the thesis considers a method for estimating the two-dimensional velocity vector within the image plane. This method, called synthetic aperture vector flow imaging, is first shortly reviewed. The main contribution of this work is partly an analysis of the method with respect to focusing effects, motion...... estimation. The method can be used for increasing the frame rate of color flow maps or alternatively for a new imaging modality entitled quadroplex imaging, featuring a color flow map and two independent spectrograms at a high frame rate. The second is an alternative method for ultrasonic vector velocity...

  2. Vector control of induction machines

    CERN Document Server

    Robyns, Benoit

    2012-01-01

    After a brief introduction to the main law of physics and fundamental concepts inherent in electromechanical conversion, ""Vector Control of Induction Machines"" introduces the standard mathematical models for induction machines - whichever rotor technology is used - as well as several squirrel-cage induction machine vector-control strategies. The use of causal ordering graphs allows systematization of the design stage, as well as standardization of the structure of control devices. ""Vector Control of Induction Machines"" suggests a unique approach aimed at reducing parameter sensitivity for

  3. Fixture for winding transformers

    Science.gov (United States)

    Mclyman, M. T.

    1980-01-01

    Bench-mounted fixture assists operator in winding toroid-shaped transformer cores. Toroid is rigidly held in place as wires are looped around. Arrangement frees both hands for rapid winding and untangling of wires that occurs when core is hand held.

  4. Wind turbines and infrasound

    International Nuclear Information System (INIS)

    Howe, B.

    2006-01-01

    This paper provided the results of a study conducted to assess the impacts of wind farm-induced infrasound on nearby residences and human populations. Infrasound occurs at frequencies below those considered as detectable by human hearing. Infrasonic levels caused by wind turbines are often similar to ambient levels of 85 dBG or lower that are caused by wind in the natural environment. This study examined the levels at which infrasound poses a threat to human health or can be considered as an annoyance. The study examined levels of infrasound caused by various types of wind turbines, and evaluated acoustic phenomena and characteristics associated with wind turbines. Results of the study suggested that infrasound near modern wind turbines is typically not perceptible to humans through either auditory or non-auditory mechanisms. However, wind turbines often create an audible broadband noise whose amplitude can be modulated at low frequencies. A review of both Canadian and international studies concluded that infrasound generated by wind turbines should not significantly impact nearby residences or human populations. 17 refs., 2 tabs., 4 figs

  5. NORCOWE Reference Wind Farm

    DEFF Research Database (Denmark)

    Bak, Thomas; Graham, Angus

    2015-01-01

    Offshore wind farms are complex systems, influenced by both the environment (e.g. wind, waves, current and seabed) and the design characteristics of the equipment available for installation (e.g. turbine type, foundations, cabling and distance to shore). These aspects govern the capital and opera...

  6. MWR, Meteor Wind Radars

    Science.gov (United States)

    Roper, R. G.

    1984-01-01

    The requirements of a state of the art meteor wind radar, and acceptable comprises in the interests of economy, are detailed. Design consideration of some existing and proposed radars are discussed. The need for international cooperation in mesopause level wind measurement, such as that being fostered by the MAP GLOBMET (Global Meteor Observations System) project, is emphasized.

  7. Research on wind energy

    CSIR Research Space (South Africa)

    Szewczuk, S

    2012-10-01

    Full Text Available & underlying technologies Ovid: composite man- rated trainer airplane Eskom?s wind farm, Klipheuwel, Cape Town ? CSIR, then DME & City of Cape Town undertook study on large grid connected wind turbines ? included a study tour to Europe. ? Recommended...

  8. Emerging wind energy technologies

    DEFF Research Database (Denmark)

    Rasmussen, Flemming; Grivel, Jean-Claude; Faber, Michael Havbro

    2014-01-01

    This chapter will discuss emerging technologies that are expected to continue the development of the wind sector to embrace new markets and to become even more competitive.......This chapter will discuss emerging technologies that are expected to continue the development of the wind sector to embrace new markets and to become even more competitive....

  9. Aerodynamics of wind turbines

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver

    Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its third edition, it has been substantially updated with respect to structural dynamics and control. The new control chapter now includes details on how to design...

  10. Aerodynamics of Wind Turbines

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver

    Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its second edition, it has been entirely updated and substantially extended to reflect advances in technology, research into rotor aerodynamics and the structural...

  11. The difficult wind power

    International Nuclear Information System (INIS)

    Groenaas, Sigbjoern

    2005-01-01

    The article presents a brief survey of the conditions for wind power production in Norway and points out that several areas should be well suited. A comparison to Danish climate is made. The wind variations, turbulence problems and regional conditions are discussed

  12. Wind Energy Systems.

    Science.gov (United States)

    Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

    During the 1920s and 1930s, millions of wind energy systems were used on farms and other locations far from utility lines. However, with passage of the Rural Electrification Act in 1939, cheap electricity was brought to rural areas. After that, the use of wind machines dramatically declined. Recently, the rapid rise in fuel prices has led to a…

  13. Fort Carson Wind Resource Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Robichaud, R.

    2012-10-01

    This report focuses on the wind resource assessment, the estimated energy production of wind turbines, and economic potential of a wind turbine project on a ridge in the southeastern portion of the Fort Carson Army base.

  14. Are Bred Vectors The Same As Lyapunov Vectors?

    Science.gov (United States)

    Kalnay, E.; Corazza, M.; Cai, M.

    Regional loss of predictability is an indication of the instability of the underlying flow, where small errors in the initial conditions (or imperfections in the model) grow to large amplitudes in finite times. The stability properties of evolving flows have been studied using Lyapunov vectors (e.g., Alligood et al, 1996, Ott, 1993, Kalnay, 2002), singular vectors (e.g., Lorenz, 1965, Farrell, 1988, Molteni and Palmer, 1993), and, more recently, with bred vectors (e.g., Szunyogh et al, 1997, Cai et al, 2001). Bred vectors (BVs) are, by construction, closely related to Lyapunov vectors (LVs). In fact, after an infinitely long breeding time, and with the use of infinitesimal ampli- tudes, bred vectors are identical to leading Lyapunov vectors. In practical applications, however, bred vectors are different from Lyapunov vectors in two important ways: a) bred vectors are never globally orthogonalized and are intrinsically local in space and time, and b) they are finite-amplitude, finite-time vectors. These two differences are very significant in a dynamical system whose size is very large. For example, the at- mosphere is large enough to have "room" for several synoptic scale instabilities (e.g., storms) to develop independently in different regions (say, North America and Aus- tralia), and it is complex enough to have several different possible types of instabilities (such as barotropic, baroclinic, convective, and even Brownian motion). Bred vectors share some of their properties with leading LVs (Corazza et al, 2001a, 2001b, Toth and Kalnay, 1993, 1997, Cai et al, 2001). For example, 1) Bred vectors are independent of the norm used to define the size of the perturba- tion. Corazza et al. (2001) showed that bred vectors obtained using a potential enstro- phy norm were indistinguishable from bred vectors obtained using a streamfunction squared norm, in contrast with singular vectors. 2) Bred vectors are independent of the length of the rescaling period as long as the

  15. Evaluating and Extending the Ocean Wind Climate Data Record

    Science.gov (United States)

    Ricciardulli, Lucrezia; Rodriguez, Ernesto; Stiles, Bryan W.; Bourassa, Mark A.; Long, David G.; Hoffman, Ross N.; Stoffelen, Ad; Verhoef, Anton; O'Neill, Larry W.; Farrar, J. Tomas; Vandemark, Douglas; Fore, Alexander G.; Hristova-Veleva, Svetla M.; Turk, F. Joseph; Gaston, Robert; Tyler, Douglas

    2017-01-01

    Satellite microwave sensors, both active scatterometers and passive radiometers, have been systematically measuring near-surface ocean winds for nearly 40 years, establishing an important legacy in studying and monitoring weather and climate variability. As an aid to such activities, the various wind datasets are being intercalibrated and merged into consistent climate data records (CDRs). The ocean wind CDRs (OW-CDRs) are evaluated by comparisons with ocean buoys and intercomparisons among the different satellite sensors and among the different data providers. Extending the OW-CDR into the future requires exploiting all available datasets, such as OSCAT-2 scheduled to launch in July 2016. Three planned methods of calibrating the OSCAT-2 σo measurements include 1) direct Ku-band σo intercalibration to QuikSCAT and RapidScat; 2) multisensor wind speed intercalibration; and 3) calibration to stable rainforest targets. Unfortunately, RapidScat failed in August 2016 and cannot be used to directly calibrate OSCAT-2. A particular future continuity concern is the absence of scheduled new or continuation radiometer missions capable of measuring wind speed. Specialized model assimilations provide 30-year long high temporal/spatial resolution wind vector grids that composite the satellite wind information from OW-CDRs of multiple satellites viewing the Earth at different local times. PMID:28824741

  16. WindSat Space Borne Polarimetric Microwave Radiometer: Data Products and System Performance

    Science.gov (United States)

    Truesdale, D.; Gaiser, P.; Bettenhausen, M. H.; Li, L.; Twarog, E.

    2017-12-01

    WindSat, a satellite-based multi-frequency polarimetric microwave radiometer developed by the Naval Research Laboratory for the U.S. Navy and the NPOESS Integrated Program Office (IPO), has collected over 14 years of fully-polarimetric microwave measurements from space since its launch in 2003. The primary WindSat mission was to demonstrate the capability to retrieve the ocean surface wind vector from a space-based microwave radiometer. The WindSat data is now being used to produce near-real-time products for the ocean surface wind vector, sea surface temperature (SST) and atmospheric columnar water vapor and cloud liquid water over the ocean at the U.S. Navy's Fleet Numerical Meteorological and Oceanographic Center (FNMOC). Several groups are assimilating WindSat data products into numerical weather models with positive results. In addition to providing environmental products over the ocean, the WindSat data set has been exploited for retrievals over land and ice. In particular, the WindSat channel set is well suited to retrieving soil moisture and land surface temperature. We have also built on heritage algorithms to derive sea ice concentration. This paper will provide highlights of WindSat environmental products. The success of the WindSat mission is directly traceable to the on-orbit sensor calibration. WindSat was designed with a one-year mission requirement and three year goal. Now in WindSat's fifteenth year on orbit, we continue to monitor the instrument performance and the calibration stability. Key system performance and calibration parameters include the receiver gains and NEDTs. These parameters are susceptible to component aging and changes in the payload thermal behavior. We will present trends in NEDT and receiver gains over the life of the mission. In addition to its primary mission, the long life of WindSat enables it to provide many forms of risk reduction and lessons learned for future microwave imagers.

  17. New techniques in 3D scalar and vector field visualization

    International Nuclear Information System (INIS)

    Max, N.; Crawfis, R.; Becker, B.

    1993-01-01

    At Lawrence Livermore National Laboratory (LLNL) we have recently developed several techniques for volume visualization of scalar and vector fields, all of which use back-to-front compositing. The first renders volume density clouds by compositing polyhedral volume cells or their faces. The second is a ''splatting'' scheme which composites textures used to reconstruct the scalar or vector fields. One version calculates the necessary texture values in software, and another takes advantage of hardware texture mapping. The next technique renders contour surface polygons using semi-transparent textures, which adjust appropriately when the surfaces deform in a flow, or change topology. The final one renders the ''flow volume'' of smoke or dye tracer swept out by a fluid flowing through a small generating polygon. All of these techniques are applied to a climate model data set, to visualize cloud density and wind velocity

  18. Offshore Wind Power

    DEFF Research Database (Denmark)

    Negra, Nicola Barberis

    The aim of the project is to investigate the influence of wind farms on the reliability of power systems. This task is particularly important for large offshore wind farms, because failure of a large wind farm might have significant influence on the balance of the power system, and because offshore...... Carlo simulation is used for these calculations: this method, in spite of an extended computation time, has shown flexibility in performing reliability studies, especially in case of wind generation, and a broad range of results which can be evaluated. The modelling is then extended to the entire power...... system considering conventional power plants, distributed generation based on wind energy and CHP technology as well as the load and transmission facilities. In particular, the different models are used to represent two well-known test systems, the RBTS and the IEEE-RTS, and to calculate...

  19. Urban Wind Energy

    DEFF Research Database (Denmark)

    Beller, Christina

    for the installation of wind turbines in cities, with Copenhagen, DK, as example. Focus is taken on turbine with a swept area of maximum 5m2, since turbines of this size are relatively easy to be integrated in the urban space and are in the financial range for small companies as well as for private persons. Elements......New trends e.g. in architecture and urban planning are to reduce energy needs. Several technologies are employed to achieve this, and one of the technologies, not new as such, is wind energy. Wind turbines are installed in cities, both by companies and private persons on both old and new buildings...... the lower wind energy in cities other factors foster the attractiveness of urban wind energy application, like the demand or wish to reduce CO2 emissions and the possibility to produce energy directly to ones household....

  20. Illinois Wind Workers Group

    Energy Technology Data Exchange (ETDEWEB)

    David G. Loomis

    2012-05-28

    The Illinois Wind Working Group (IWWG) was founded in 2006 with about 15 members. It has grown to over 200 members today representing all aspects of the wind industry across the State of Illinois. In 2008, the IWWG developed a strategic plan to give direction to the group and its activities. The strategic plan identifies ways to address critical market barriers to the further penetration of wind. The key to addressing these market barriers is public education and outreach. Since Illinois has a restructured electricity market, utilities no longer have a strong control over the addition of new capacity within the state. Instead, market acceptance depends on willing landowners to lease land and willing county officials to site wind farms. Many times these groups are uninformed about the benefits of wind energy and unfamiliar with the process. Therefore, many of the project objectives focus on conferences, forum, databases and research that will allow these stakeholders to make well-educated decisions.

  1. Aeroservoelasticity of Wind Turbines

    DEFF Research Database (Denmark)

    Kallesøe, Bjarne Skovmose

    2007-01-01

    This thesis deals with the fundamental aeroelastic interaction between structural motion, Pitch action and control for a wind turbine blade. As wind turbines become larger, the interaction between pitch action, blade motion, aerodynamic forces, and control become even more important to understand...... to a 2D blade section model, and it can be used instead of this in many applications, giving a transparent connection to a real wind turbine blade. In this work the aeroelastic blade model is used to analyze interaction between pitch action, blade motion and wind speed variations. Furthermore the model...... conditions. So, a new aeroelastic blade model has been derived, which includes important features of large wind turbines, yet simple enough to be suitable for analytical analysis and control design....

  2. Aerodynamics of Wind Turbines

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver

    Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its second edition, it has been entirely updated and substantially extended to reflect advances in technology, research into rotor aerodynamics and the structural...... response of the wind turbine structure. Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element...... Momentum method is also covered, as are eigenmodes and the dynamic behavior of a turbine. The new material includes a description of the effects of the dynamics and how this can be modeled in an aeroelastic code, which is widely used in the design and verification of modern wind turbines. Further...

  3. The wind energy potential in Argentina

    International Nuclear Information System (INIS)

    Alvarez, P

    2005-01-01

    associates with the wind generation, it is hardly to manage the incorporation to the network of a major part of this extraordinary potential without the aid of some type of stage of intermediate accumulation.In fact, to take full advantage of the wind energy rests in the adoption of electrolytic made hydrogen as 'vector' of the wind energy and/or in the development of 'wind-hydro' hybrid power stations with possibility of accumulation by pumping.The calculation has been based on a known methodology used in similar international works and the use of a Geographical Information System (GIS) that it has revealed to be a tool of enormous utility for this task.The base data are public and are available in the web page of the Secretariat of Energy: http://energia.mecon.gov.ar

  4. Vectorization at the KENO-IV code

    International Nuclear Information System (INIS)

    Asai, K.; Higuchi, K.; Katakura, J.

    1986-01-01

    The multigroup criticality safety code KENO-IV has been vectorized and tested on the FACOM VP-100 vector processor. At first, the vectorized KENO-IV on a scalar processor was slower than the original one by a factor of 1.4 because of the overhead introduced by vectorization. Making modifications of algorithms and techniques for vectorization, the vectorized version has become faster than the original one by a factor of 1.4 on the vector processor. For further speedup of the code, some improvements on compiler and hardware, especially on addition of Monte Carlo pipelines to the vector processor, are discussed

  5. European Wind Atlas and Wind Resource Research in Denmark

    DEFF Research Database (Denmark)

    Mortensen, Niels Gylling

    to estimate the actual wind climate at any specific site and height within this region. The Danish and European Wind Atlases are examples of how the wind atlas methodology can be employed to estimate the wind resource potential for a country or a sub-continent. Recently, the methodology has also been used...... - from wind measurements at prospective sites to wind tunnel simulations and advanced flow modelling. Among these approaches, the wind atlas methodology - developed at Ris0 National Laboratory over the last 25 years - has gained widespread recognition and is presently considered by many as the industry......-standard tool for wind resource assessment and siting of wind turbines. The PC-implementation of the methodology, the Wind Atlas Analysis and Application Program (WAsP), has been applied in more than 70 countries and territories world-wide. The wind atlas methodology is based on physical descriptions and models...

  6. Introduction to matrices and vectors

    CERN Document Server

    Schwartz, Jacob T

    2001-01-01

    In this concise undergraduate text, the first three chapters present the basics of matrices - in later chapters the author shows how to use vectors and matrices to solve systems of linear equations. 1961 edition.

  7. Disease Vector Ecology Profile: Ecuador

    Science.gov (United States)

    1998-12-01

    biologically an inefficient vector, has an insatiable feeding preference for Rattus spp., Cavia porcellus (guinea pigs), domestic animals (swine...71 Peru – 11 Institutos Nacionales de Salud Departamento de Animales Venenosos Calle Capac Yupanqui 1400 Apartado 451 Lima, Peru TEL

  8. GRE Enzymes for Vector Analysis

    Data.gov (United States)

    U.S. Environmental Protection Agency — Microbial enzyme data that were collected during the 2004-2006 EMAP-GRE program. These data were then used by Moorhead et al (2016) in their ecoenzyme vector...

  9. High Accuracy Vector Helium Magnetometer

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed HAVHM instrument is a laser-pumped helium magnetometer with both triaxial vector and omnidirectional scalar measurement capabilities in a single...

  10. Characterization of wind velocities in the wake of a full scale wind turbine using three ground-based synchronized WindScanners

    Science.gov (United States)

    Yazicioglu, Hasan; Angelou, Nikolas; Mikkelsen, Torben; José Trujillo, Juan

    2016-09-01

    The wind energy community is in need of detailed full-field measurements in the wake of wind turbines. Here, three dimensional(3D) wind vector field measurements obtained in the near-wake region behind a full-scale test turbine are presented. Specifically, the wake of a NEG Nordtank turbine, installed at Risoe test field, has been measured from 0 to 2 diameters downstream. For this, three ground-based synchronised short-range WindScanners and a spinner lidar have been used. The 3D wind velocity field has been reconstructed in horizontal and vertical planes crossing the hub. The 10-min mean values of the three wind components reveal detailed information regarding the wake properties while propagating downwind over flat terrain. Furthermore, the wake centre is tracked from the measurements and its meander is investigated as function of yaw misalignment of the turbine. The centre-line wake deficit is calculated both in a Nacelle and Moving Frame of Reference. The results can be used in quantitative validation of numerical wake models.

  11. Wind and tornado guidelines

    International Nuclear Information System (INIS)

    McDonald, J.R.

    1989-01-01

    The objective of the Department of Energy Natural Phenomena Hazards Project is to provide guidance and criteria for design of new facilities and for evaluation of existing ones subjected to extreme winds, earthquakes, and floods. This paper describes the treatment of wind and tornado hazards. Four facility-use categories are defined which represent increasing levels of risk to personnel or the environment in the event of a high wind event. Facilities are assigned to a particular category, depending on their mission, value, or toxic material content. The assigned facility-use category determines the design and evaluation criteria. The criteria are based on probabilistic hazard assessment. Performance goals are also specified for each facility-use category. A uniform approach to design wind loads, based on the ANSI A58.1-1982 standard, allows treatment of high winds and hurricane and tornado winds in a similar manner. Based on the wind hazard models, some sites must account for the possibility of tornadoes while others do not. Atmospheric pressure changes and missiles must be taken into account when considering tornadoes. The design and evaluation guidelines are designed to establish consistent levels of risk for different natural phenomena hazards and for facilities at different geographical locations

  12. Wind energy in Europe

    International Nuclear Information System (INIS)

    Sesto, E.

    1992-02-01

    Interest in wind energy as a supplementary source for the production of electricity has recently gained renewed momentum due to widespread concern about environmental impacts from the large scale use of fossil fuels and nuclear energy. In addition, political unrest in the Middle East has drawn attention to the importance of national energy self-sufficiency. European government administrations, however, have not yet fully appreciated the real worth of the 'clean energy' afforded by wind energy. In this regard, the European Wind Energy Association (EWEA) is acting as a strong voice to inform the public and energy planners by stimulating international wind energy R ampersand D cooperation, and organizing conferences to explain the advantages of wind energy. In October 1991, EWEA published a strategy document giving a picture of the real possibilities offered by wind energy within the geographical, social, and European economic context. This paper provides an overview of the more significant features to emerge from this document which represents a useful guideline for wind power plant technical/economic feasibility studies in that it contains brief notes on resource availability, land requirements, visual and acoustic impacts, turbine sizing, performance, interconnection to utility grids, maintenance and operating costs, safety, as well as, on marketing aspects

  13. Wind farms and planning

    International Nuclear Information System (INIS)

    Arkesteijn, L.; Havinga, R.; Benner, J.H.B.

    1992-01-01

    The siting of wind farms is becoming an increasingly important issue in the Netherlands. This paper gives an overview of the current situation concerning the planning of wind farms. We will pay attention to: Wind energy in official Dutch planning policy. To select the optimal sites, the government has made an administrative agreement with the 7 windy provinces. Nevertheless, wind energy is still fighting for a rightful position in physical planning policy. Some examples will illustrate this. Studies on siting and siting problems in the Netherlands. In order to gain more insight into aspects of wind farming several studies have been executed. In this paper special attention will be paid to the results of a study on the potential impact of large windturbine clusters on an existing agricutural area. Experiences with siting of wind farms in the Netherlands. Based on experiences with the planning and realization of farms, this paper gives the main problems. In the final part of the paper we present some general conclusions. Generally speaking, the knowledge is available for selecting optimal sites in the Netherlands. The basic problems for wind farming nowadays seem to be the visual impact and actually obtaining the ground. Nevertheless, there do seem to be enough sites for realizing the goals in the Netherlands. (au)

  14. Database on wind characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, K.S. [The Technical Univ. of Denmark (Denmark); Courtney, M.S. [Risoe National Lab., (Denmark)

    1999-08-01

    The organisations that participated in the project consists of five research organisations: MIUU (Sweden), ECN (The Netherlands), CRES (Greece), DTU (Denmark), Risoe (Denmark) and one wind turbine manufacturer: Vestas Wind System A/S (Denmark). The overall goal was to build a database consisting of a large number of wind speed time series and create tools for efficiently searching through the data to select interesting data. The project resulted in a database located at DTU, Denmark with online access through the Internet. The database contains more than 50.000 hours of measured wind speed measurements. A wide range of wind climates and terrain types are represented with significant amounts of time series. Data have been chosen selectively with a deliberate over-representation of high wind and complex terrain cases. This makes the database ideal for wind turbine design needs but completely unsuitable for resource studies. Diversity has also been an important aim and this is realised with data from a large range of terrain types; everything from offshore to mountain, from Norway to Greece. (EHS)

  15. The Forecasting Procedure for Long-Term Wind Speed in the Zhangye Area

    Directory of Open Access Journals (Sweden)

    Zhenhai Guo

    2010-01-01

    Full Text Available Energy crisis has made it urgent to find alternative energy sources for sustainable energy supply; wind energy is one of the attractive alternatives. Within a wind energy system, the wind speed is one key parameter; accurately forecasting of wind speed can minimize the scheduling errors and in turn increase the reliability of the electric power grid and reduce the power market ancillary service costs. This paper proposes a new hybrid model for long-term wind speed forecasting based on the first definite season index method and the Autoregressive Moving Average (ARMA models or the Generalized Autoregressive Conditional Heteroskedasticity (GARCH forecasting models. The forecasting errors are analyzed and compared with the ones obtained from the ARMA, GARCH model, and Support Vector Machine (SVM; the simulation process and results show that the developed method is simple and quite efficient for daily average wind speed forecasting of Hexi Corridor in China.

  16. Improving Low Voltage Ride Through Capability of Wind Generators Using Dynamic Voltage Restorer

    Science.gov (United States)

    Sivasankar, Gangatharan; Suresh Kumar, Velu

    2014-08-01

    The increasing wind power integration with power grid has forced the situation to improve the reliability of wind generators for stable operation. One important problem with induction generator based wind farm is its low ride through capability to the grid voltage disturbance. Any disturbance such as voltage dip may cause wind farm outages. Since wind power contribution is in predominant percentage, such outages may lead to stability problem. The proposed strategy is to use dynamic voltage controller (DVR) to compensate the voltage disturbance. The DVR provides the wind generator the ability to remain connected in grid and improve the reliability. The voltage dips due to symmetrical and unsymmetrical faults are considered for analysis. The vector control scheme is employed for fault compensation which uses software phase locked loop scheme and park dq0 transformation technique. Extensive simulation results are included to illustrate the control and operation of DVR.

  17. Time series analysis of wind speed using VAR and the generalized impulse response technique

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, Bradley T. [Area of Information Systems and Quantitative Sciences, Rawls College of Business and Wind Science and Engineering Research Center, Texas Tech University, Lubbock, TX 79409-2101 (United States); Kruse, Jamie Brown [Center for Natural Hazard Research, East Carolina University, Greenville, NC (United States); Schroeder, John L. [Department of Geosciences and Wind Science and Engineering Research Center, Texas Tech University, Lubbock, TX (United States); Smith, Douglas A. [Department of Civil Engineering and Wind Science and Engineering Research Center, Texas Tech University, Lubbock, TX (United States)

    2007-03-15

    This research examines the interdependence in time series wind speed data measured in the same location at four different heights. A multiple-equation system known as a vector autoregression is proposed for characterizing the time series dynamics of wind. Additionally, the recently developed method of generalized impulse response analysis provides insight into the cross-effects of the wind series and their responses to shocks. Findings are based on analysis of contemporaneous wind speed time histories taken at 13, 33, 70 and 160 ft above ground level with a sampling rate of 10 Hz. The results indicate that wind speeds measured at 70 ft was the most variable. Further, the turbulence persisted longer at the 70-ft measurement than at the other heights. The greatest interdependence is observed at 13 ft. Gusts at 160 ft led to the greatest persistence to an 'own' shock and led to greatest persistence in the responses of the other wind series. (author)

  18. Mongolia wind resource assessment project

    International Nuclear Information System (INIS)

    Elliott, D.; Chadraa, B.; Natsagdorj, L.

    1998-01-01

    The development of detailed, regional wind-resource distributions and other pertinent wind resource characteristics (e.g., assessment maps and reliable estimates of seasonal, diurnal, and directional) is an important step in planning and accelerating the deployment of wind energy systems. This paper summarizes the approach and methods being used to conduct a wind energy resource assessment of Mongolia. The primary goals of this project are to develop a comprehensive wind energy resource atlas of Mongolia and to establish a wind measurement program in specific regions of Mongolia to identify prospective sites for wind energy projects and to help validate some of the wind resource estimates. The Mongolian wind resource atlas will include detailed, computerized wind power maps and other valuable wind resource characteristic information for the different regions of Mongolia

  19. Type IV Wind Turbine Model

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Margaris, Ioannis D.

    (WPP) will be considered. The aggregate WPP model, which will be based on the upscaling of the individual wind turbine model on the electrical part, will make use of an equivalent wind speed. The implemented model follows the basic structure of the generic standard Type 4 wind turbine model proposed...... by the International Electrotechnical Commission (IEC), in the IEC61400-27-1 Committee Draft for electrical simulation models for wind power generation, which is currently under review, [1]. The Type 4 wind turbine model described in this report includes a set of adjustments of the standard Type 4 wind turbine model...... project to be incorporated in the wind power plant level. This document describes the Type 4 wind turbine simulation model, implemented in the EaseWind project. The implemented wind turbine model is one of the initial necessary steps toward integrating new control services in the wind power plant level...

  20. Satellite winds as a tool for offshore wind resource assessment: The Great Lakes Wind Atlas

    DEFF Research Database (Denmark)

    Doubrawa, Paula; Barthelmie, Rebecca Jane; Pryor, Sara C.

    2015-01-01

    This work presents a new observational wind atlas for the Great Lakes, and proposes a methodology to combine in situ and satellite wind observations for offshore wind resource assessment. Efficient wind energy projects rely on accurate wind resource estimates, which are complex to obtain offshore...... the North American Regional Reanalysis. Generalized wind climates are obtained for each buoy and coastal site with the wind model WAsP, and combined into a single wind speed estimate for the Great Lakes region. The method of classes is used to account for the temporal sparseness in the SAR data set...

  1. Wind for Schools: A Wind Powering America Project

    Science.gov (United States)

    US Department of Energy, 2007

    2007-01-01

    The U.S. Department of Energy's (DOE's) Wind Powering America program (based at the National Renewable Energy Laboratory) sponsors the Wind for Schools Project to raise awareness in rural America about the benefits of wind energy while simultaneously educating college seniors regarding wind energy applications. The three primary project goals of…

  2. Operation Design of Wind Turbines in Strong Wind Conditions

    DEFF Research Database (Denmark)

    Shen, Wen Zhong; Montes, Melissa Barroso; Odgaard, Peter Fogh

    2012-01-01

    and variable speed pitch regulated wind turbines. The variable speed design is more suitable for wind turbines to run at very high wind speeds which can help the turbine braking system to stop the turbine at the new "cut-out" wind speed. Reference power, rotational speed and pitch angle have been designed...

  3. Offshore wind speed and wind power characteristics for ten ...

    Indian Academy of Sciences (India)

    This paper utilizes wind speed data measured at 3 and 10 m above water surface level using buoys at 10 stations in Ionian and Aegean Seas to understand the behaviour of wind and thereafter energy yield at these stations using 5 MW rated power offshore wind turbine. With wind power densities of 971 and 693 W/m2 at ...

  4. Wind Turbine Converter Control Interaction with Complex Wind Farm Systems

    DEFF Research Database (Denmark)

    Kocewiak, Lukasz Hubert; Hjerrild, Jesper; Bak, Claus Leth

    2013-01-01

    in this study. It is shown that wind farm components, such as long high-voltage alternating current cables and park transformers, can introduce significant low-frequency series resonances seen from the wind turbine terminals that can affect wind turbine control system operation and overall wind farm stability...

  5. Assessing the vegetation canopy influences on wind flow using wind ...

    Indian Academy of Sciences (India)

    The effectiveness of vegetation in reducing wind ... Wind erosion; roughness length; shear velocity ratio; shear stress ratio; roughness density; wind tunnel. J. Earth .... flow direction induced by its kinematic viscosity. An increase in shear stress causes a proportional increase in the height-dependent change in wind velocity.

  6. Sensing the wind profile

    DEFF Research Database (Denmark)

    Pena Diaz, Alfredo

    This thesis consists of two parts. The first is a synopsis of the theoretical progress of the study that is based on a number of journal papers. The papers, which constitute the second part of the report, aim to analyze, measure, and model the wind prole in and beyond the surface layer by combining...... measurements are averaged for several stability conditions and compare well with the surface-layer wind profile. At Høvsøre, it is sufficient to scale the wind speed with the surface friction velocity, whereas at Horns Rev a new scaling is added, due to the variant roughness length. This new scaling is coupled...

  7. Wind Farm Wake

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Karagali, Ioanna; Volker, Patrick

    2017-01-01

    together to investigate the atmospheric conditions at the time of the photos by analysing local meteorological observations and wind turbine information, satellite remote sensing and nearby radiosonde data. Two wake models and one mesoscale model were used to model the case and explain what was seen.......On 25 January 2016 at 12:45 UTC several photographs of the offshore wind farm Horns Rev 2 were taken by helicopter pilot Gitte Lundorff with an iPhone. A very shallow layer of fog covered the sea. The photos of the fog over the sea dramatically pictured the offshore wind farm wake. Researchers got...

  8. Financing renewables - wind energy

    International Nuclear Information System (INIS)

    Armstrong, J.

    1998-01-01

    This paper describes the status of the wind energy markets world-wide, in Europe and in the UK. It outlines the main methods of financing wind energy installations and discusses why different institutional structures have led to different markets in the UK and in Germany, with some concern about the state of the UK onshore industry. The paper looks ahead to the opening up of the potentially much larger offshore wind resource, concluding that in this area, existing UK development and financing structures are well suited. (Author)

  9. Equivalent models of wind farms by using aggregated wind turbines and equivalent winds

    International Nuclear Information System (INIS)

    Fernandez, L.M.; Garcia, C.A.; Saenz, J.R.; Jurado, F.

    2009-01-01

    As a result of the increasing wind farms penetration on power systems, the wind farms begin to influence power system, and therefore the modeling of wind farms has become an interesting research topic. In this paper, new equivalent models of wind farms equipped with wind turbines based on squirrel-cage induction generators and doubly-fed induction generators are proposed to represent the collective behavior on large power systems simulations, instead of using a complete model of wind farms where all the wind turbines are modeled. The models proposed here are based on aggregating wind turbines into an equivalent wind turbine which receives an equivalent wind of the ones incident on the aggregated wind turbines. The equivalent wind turbine presents re-scaled power capacity and the same complete model as the individual wind turbines, which supposes the main feature of the present equivalent models. Two equivalent winds are evaluated in this work: (1) the average wind from the ones incident on the aggregated wind turbines with similar winds, and (2) an equivalent incoming wind derived from the power curve and the wind incident on each wind turbine. The effectiveness of the equivalent models to represent the collective response of the wind farm at the point of common coupling to grid is demonstrated by comparison with the wind farm response obtained from the detailed model during power system dynamic simulations, such as wind fluctuations and a grid disturbance. The present models can be used for grid integration studies of large power system with an important reduction of the model order and the computation time

  10. Wind turbine influence on surfers wind conditions at Hanstholm

    DEFF Research Database (Denmark)

    Larsen, Torben J.; Andersen, Søren Juhl

    alter the wind conditions on the lee side, which is an important area for wind and kite surfers. The Dynamic Wake Meander Model is used to investigate the wind conditions north east of the planned new turbines at Hanstholm covering a surf area from a location called “Fish Factory” to a location called...... “Hamborg”. This model, which predicts instationary wind conditions behind one or more wind turbines, has previously been used to predict the changed power and load conditions for wind turbines in wind farm conditions. Avery fine agreement to measurements is seen and the model is therefore considered...

  11. Wind resource estimation and siting of wind turbines

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik; Mortensen, N.G.; Landberg, L.

    1994-01-01

    Detailed knowledge of the characteristics of the natural wind is necessary for the design, planning and operational aspect of wind energy systems. Here, we shall only be concerned with those meteorological aspects of wind energy planning that are termed wind resource estimation. The estimation...... of the wind resource ranges from the overall estimation of the mean energy content of the wind over a large area - called regional assessment - to the prediction of the average yearly energy production of a specific wind turbine at a specific location - called siting. A regional assessment will most often...

  12. Short-term wind power prediction based on LSSVM–GSA model

    International Nuclear Information System (INIS)

    Yuan, Xiaohui; Chen, Chen; Yuan, Yanbin; Huang, Yuehua; Tan, Qingxiong

    2015-01-01

    Highlights: • A hybrid model is developed for short-term wind power prediction. • The model is based on LSSVM and gravitational search algorithm. • Gravitational search algorithm is used to optimize parameters of LSSVM. • Effect of different kernel function of LSSVM on wind power prediction is discussed. • Comparative studies show that prediction accuracy of wind power is improved. - Abstract: Wind power forecasting can improve the economical and technical integration of wind energy into the existing electricity grid. Due to its intermittency and randomness, it is hard to forecast wind power accurately. For the purpose of utilizing wind power to the utmost extent, it is very important to make an accurate prediction of the output power of a wind farm under the premise of guaranteeing the security and the stability of the operation of the power system. In this paper, a hybrid model (LSSVM–GSA) based on the least squares support vector machine (LSSVM) and gravitational search algorithm (GSA) is proposed to forecast the short-term wind power. As the kernel function and the related parameters of the LSSVM have a great influence on the performance of the prediction model, the paper establishes LSSVM model based on different kernel functions for short-term wind power prediction. And then an optimal kernel function is determined and the parameters of the LSSVM model are optimized by using GSA. Compared with the Back Propagation (BP) neural network and support vector machine (SVM) model, the simulation results show that the hybrid LSSVM–GSA model based on exponential radial basis kernel function and GSA has higher accuracy for short-term wind power prediction. Therefore, the proposed LSSVM–GSA is a better model for short-term wind power prediction

  13. Simultaneous measurements of the thermospheric wind profile at three separate positions in the dusk auroral oval

    International Nuclear Information System (INIS)

    Mikkelsen, I.S.; Friis-Christensen, E.; Larsen, M.F.; Kelley, M.C.; Vickrey, J.; Meriwether, J.; Shih, P.

    1987-01-01

    On March 20, 1985, two rockets were launched from Soendre Stroemfjord, Greenland, into the dusk auroral oval. Three trimethyl aluminium trails were released to measure the neutral wind profiles between 95 and 190 km of altitude at two points separated by 190 km normal to the invariant latitude circles and at a third point separated from the first two by 300 km along the invariant latitude circles. Two barium/strontium clouds were released at 250 km of altitude, extending two of the neutral wind profiles to this altitude. In the E region the tip of the wind vector traced an ellipse as a function of increasing altitude with maximum wind speeds of 100-150 m/s in the southeastward and northwestward directions. The F region winds were southward with speeds of 100-200 m/s. The zonal wind component between 115 and 140 km of altitude had a horizontal gradient in the southeastward direction, whereas the meridional wind component at the same heights was constant over the spatial extent covered by the measurements. The authors interpret the observed E region wind field as being part of a gravity wave with a period of 3 hours as estimated from the ellipticity of the wind hodograms. The wind vectors rotated 540 degree clockwise with increasing height, indicating that the wave energy is propagating upward. The Fabry-Perot interferometer at Soendre Stroemfjord was first able to detect the F region winds 45 min after the releases and measured winds of 100-400 m/s mainly in the southeastward or antisunward direction. The geomagnetic conditions were quiet, with Kp not exceeding 2 for the 24 hours preceding the experiment. The incoherent scatter radar at Soendre Stroemfjord observed a contracted plasma convection pattern associated with positive B y and B z components of the interplanetary magnetic field

  14. Decays of the vector glueball

    Science.gov (United States)

    Giacosa, Francesco; Sammet, Julia; Janowski, Stanislaus

    2017-06-01

    We calculate two- and three-body decays of the (lightest) vector glueball into (pseudo)scalar, (axial-)vector, as well as pseudovector and excited vector mesons in the framework of a model of QCD. While absolute values of widths cannot be predicted because the corresponding coupling constants are unknown, some interesting branching ratios can be evaluated by setting the mass of the yet hypothetical vector glueball to 3.8 GeV as predicted by quenched lattice QCD. We find that the decay mode ω π π should be one of the largest (both through the decay chain O →b1π →ω π π and through the direct coupling O →ω π π ). Similarly, the (direct and indirect) decay into π K K*(892 ) is sizable. Moreover, the decays into ρ π and K*(892 )K are, although subleading, possible and could play a role in explaining the ρ π puzzle of the charmonium state ψ (2 S ) thanks to a (small) mixing with the vector glueball. The vector glueball can be directly formed at the ongoing BESIII experiment as well as at the future PANDA experiment at the FAIR facility. If the width is sufficiently small (≲100 MeV ) it should not escape future detection. It should be stressed that the employed model is based on some inputs and simplifying assumptions: the value of glueball mass (at present, the quenched lattice value is used), the lack of mixing of the glueball with other quarkonium states, and the use of few interaction terms. It then represents a first step toward the identification of the main decay channels of the vector glueball, but shall be improved when corresponding experimental candidates and/or new lattice results will be available.

  15. Design of intelligent controllers for wind generation system with sensorless maximum wind energy control

    International Nuclear Information System (INIS)

    Lin, Whei-Min; Hong, Chih-Ming; Cheng, Fu-Sheng

    2011-01-01

    This paper presents the design of an on-line training recurrent fuzzy neural network (RFNN) controller with a high-performance model reference adaptive system (MRAS) observer for the sensorless control of a induction generator (IG). The modified particle swarm optimization (MPSO) is adopted in this study to adapt the learning rates in the back-propagation process of the RFNN to improve the learning capability. By using the proposed RFNN controller with MPSO, the IG system can work for stand-alone power application effectively. The proposed output maximization control is achieved without mechanical sensors such as the wind speed or position sensor, and the new control system will deliver maximum electric power with light weight, high efficiency, and high reliability. The estimation of the rotor speed is based on the MRAS control theory. A sensorless vector-control strategy for an IG operating in a grid-connected variable speed wind energy conversion system can be achieved.

  16. Local Patch Vectors Encoded by Fisher Vectors for Image Classification

    Directory of Open Access Journals (Sweden)

    Shuangshuang Chen

    2018-02-01

    Full Text Available The objective of this work is image classification, whose purpose is to group images into corresponding semantic categories. Four contributions are made as follows: (i For computational simplicity and efficiency, we directly adopt raw image patch vectors as local descriptors encoded by Fisher vector (FV subsequently; (ii For obtaining representative local features within the FV encoding framework, we compare and analyze three typical sampling strategies: random sampling, saliency-based sampling and dense sampling; (iii In order to embed both global and local spatial information into local features, we construct an improved spatial geometry structure which shows good performance; (iv For reducing the storage and CPU costs of high dimensional vectors, we adopt a new feature selection method based on supervised mutual information (MI, which chooses features by an importance sorting algorithm. We report experimental results on dataset STL-10. It shows very promising performance with this simple and efficient framework compared to conventional methods.

  17. Learning with LOGO: Logo and Vectors.

    Science.gov (United States)

    Lough, Tom; Tipps, Steve

    1986-01-01

    This is the first of a two-part series on the general concept of vector space. Provides tool procedures to allow investigation of vector properties, vector addition and subtraction, and X and Y components. Lists several sources of additional vector ideas. (JM)

  18. Operation and control of large wind turbines and wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Poul; Hansen, Anca D.; Thomsen, Kenneth (and others)

    2005-09-01

    This report is the final report of a Danish research project 'Operation and control of large wind turbines and wind farms'. The objective of the project has been to analyse and assess operational strategies and possibilities for control of different types of wind turbines and different wind farm concepts. The potentials of optimising the lifetime/energy production ratio by means of using revised operational strategies for the individual wind turbines are investigated. Different strategies have been simulated, where the power production is decreased to an optimum when taking loads and actual price of produced electricity into account. Dynamic models and control strategies for the wind farms have also been developed, with the aim to optimise the operation of the wind farms considering participation in power system control of power (frequency) and reactive power (voltage), maximise power production, keep good power quality and limit mechanical loads and life time consumption. The project developed models for 3 different concepts for wind farms. Two of the concepts use active stall controlled wind turbines, one with AC connection and one with modern HVDC/VSC connection of the wind farm. The third concept is based on pitch controlled wind turbines using doubly fed induction generators. The models were applied to simulate the behaviour of the wind farm control when they were connected to a strong grid, and some initial simulations were performed to study the behaviour of the wind farms when it was isolated from the main grid on a local grid. Also the possibility to use the available information from the wind turbine controllers to predict the wind speed has been investigated. The main idea has been to predict the wind speed at a wind turbine using up-wind measurements of the wind speed in another wind turbine. (au)

  19. Wind Turbine Acoustics

    Science.gov (United States)

    Hubbard, Harvey H.; Shepherd, Kevin P.

    2009-01-01

    Wind turbine generators, ranging in size from a few kilowatts to several megawatts, are producing electricity both singly and in wind power stations that encompass hundreds of machines. Many installations are in uninhabited areas far from established residences, and therefore there are no apparent environmental impacts in terms of noise. There is, however, the potential for situations in which the radiated noise can be heard by residents of adjacent neighborhoods, particularly those neighborhoods with low ambient noise levels. A widely publicized incident of this nature occurred with the operation of the experimental Mod-1 2-MW wind turbine, which is described in detail elsewhere. Pioneering studies which were conducted at the Mod-1 site on the causes and remedies of noise from wind turbines form the foundation of much of the technology described in this chapter.

  20. Wind farm production estimates

    DEFF Research Database (Denmark)

    Larsen, Torben J.; Larsen, Gunner Chr.; Aagaard Madsen, Helge

    2012-01-01

    inves- tigated for a full polar (i.e. as function of mean inflow wind direction). This investigation relates to a mean wind speed bin defined as 8m=s±1m=s. The impact of ambient turbu- lence intensity and turbine inter spacing on the production of a wind turbine operating under full wake conditions...... is investi- gated. Four different turbine inter spacings, ranging between 3.8 and 10.4 rotor diameters, are analyzed for ambient turbu- lence intensities varying between 2% and 20%. This analysis is based on full scale production data from three other wind farms Wieringermeer [3], Horns Rev [4] and Nysted [5......]. A very satisfactory agreement between experimental data and predictions is observed. This paper finally includes additionally an analysis of the production impact caused by atmospheric stability effects. For this study, atmospheric stability conditions are defined in terms of the Monin-Obukhov length...

  1. Superconducting wind turbine generators

    DEFF Research Database (Denmark)

    Mijatovic, Nenad

    in this thesis is a part of a larger endeavor, the Superwind project that focused on identifying the potentials that HTS machines could offer to the wind industry and addressing some of the challenges in the process. In order to identify these challenges, I have designed and constructed an HTS machine......A HTS machine could be a way to address some of the technical barriers offshore wind energy is about to face. Due to the superior power density of HTS machines, this technology could become a milestone on which many, including the wind industry, will rely on in the future. The work presented...... experimental setup which is made to serve as precursor, leading towards an optimized HTS machine concept proposed for wind turbines. In part, the work presented in this thesis will focus on the description of the experimental setup and reasoning behind the choices made during the design. The setup comprises...

  2. 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...

  3. South Baltic Wind Atlas

    DEFF Research Database (Denmark)

    Pena Diaz, Alfredo; Hahmann, Andrea N.; Hasager, Charlotte Bay

    A first version of a wind atlas for the South Baltic Sea has been developed using the WRF mesoscale model and verified by data from tall Danish and German masts. Six different boundary-layer parametrization schemes were evaluated by comparing the WRF results to the observed wind profiles...... at the masts. The WRF modeling was done in a nested domain of high spatial resolution for 4 years. In addition the longterm wind statistics using the NCAR-NCEP reanalysis data were performed during 30 years to provide basis for a long-term adjustment of the results and the final WRF results include a weighting...... for the long-term trends variability in the South Baltic Sea. Observations from Earth observing satellites were used to evaluate the spatial resolution of the WRF model results near the surface. The QuikSCAT and the WRF results compared well whereas the Envisat ASAR mean wind map showed some variation...

  4. Noise from wind turbines

    International Nuclear Information System (INIS)

    Andersen, B.; Larsen, P.

    1993-01-01

    Denmark has 3200 wind turbines with an installed maximum capacity of 418MW. The most important Danish research projects into wind turbine noise and the main results are listed. These date from 1983. Two comprehensive studies are currently in progress. The first is an analytical and empirical investigation of aerodynamic noise from wind turbine rotors and has so far dealt mainly with tip noise. The measurement method, using a hard board mounted microphone on the ground near the turbine, is described. Four different tip designs have been tested. Some examples of reference sound power level spectra for three of the designs are presented. During the past two years a computerbased data acquisition system has been used for real-time determination of sound power levels. The second study, which has just commenced, is on annoyance from wind turbine noise. It will include noise measurements, masking calculations and a social survey on the perceived nuisance. (UK)

  5. Aerodynamics of wind turbines

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver

    Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its third edition, it has been substantially updated with respect to structural dynamics and control. The new control chapter now includes details on how to design...... a classical pitch and torque regulator to control rotational speed and power, while the section on structural dynamics has been extended with a simplified mechanical system explaining the phenomena of forward and backward whirling modes. Readers will also benefit from a new chapter on Vertical Axis Wind...... Turbines (VAWT). Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element Momentum method...

  6. Wind Profiling Radar

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Clutter present in radar return signals as used for wind profiling is substantially removed by carrying out a Daubechies wavelet transformation on a time series of...

  7. Distributed Wind Market Applications

    Energy Technology Data Exchange (ETDEWEB)

    Forsyth, T.; Baring-Gould, I.

    2007-11-01

    Distributed wind energy systems provide clean, renewable power for on-site use and help relieve pressure on the power grid while providing jobs and contributing to energy security for homes, farms, schools, factories, private and public facilities, distribution utilities, and remote locations. America pioneered small wind technology in the 1920s, and it is the only renewable energy industry segment that the United States still dominates in technology, manufacturing, and world market share. The series of analyses covered by this report were conducted to assess some of the most likely ways that advanced wind turbines could be utilized apart from large, central station power systems. Each chapter represents a final report on specific market segments written by leading experts in this field. As such, this document does not speak with one voice but rather a compendium of different perspectives, which are documented from a variety of people in the U.S. distributed wind field.

  8. Wind Tunnel Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This ARDEC facility consists of subsonic, transonic, and supersonic wind tunnels to acquire aerodynamic data. Full-scale and sub-scale models of munitions are fitted...

  9. Aerodynamics of wind turbines

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver

    Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its third edition, it has been substantially updated with respect to structural dynamics and control. The new control chapter now includes details on how to design...... Turbines (VAWT). Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element Momentum method...... is also covered, as are eigenmodes and the dynamic behaviour of a turbine. The book describes the effects of the dynamics and how this can be modelled in an aeroelastic code, which is widely used in the design and verification of modern wind turbines. Furthermore, it examines how to calculate...

  10. Monitoring of wind turbines

    Science.gov (United States)

    White, Jonathan R.; Adams, Douglas E.; Paquette, Josh

    2017-07-25

    Method and apparatus for determining the deflection or curvature of a rotating blade, such as a wind turbine blade or a helicopter blade. Also, methods and apparatus for establishing an inertial reference system on a rotating blade.

  11. Performance of Wind Pump Prototype

    African Journals Online (AJOL)

    Mulu

    performance of the wind pump. One year wind speed data collected at 10 m height was extrapolated to the wind pump hub height using wind shear coefficient. The model assumed balanced rotor power and reciprocating pump, hence did not consider the effect of pump size. The theoretical model estimated the average ...

  12. 2010 Wind Technologies Market Report

    Energy Technology Data Exchange (ETDEWEB)

    Ryan Wiser, Mark Bolinger

    2011-06-01

    This report provides a comprehensive overview of trends in the U.S. wind power market in 2010. The report analyzes trends in wind power capacity, industry, manufacturing, turbines, installed project costs, project performance, and wind power prices. It also describes trends among wind power developers, project owners, and power purchasers, and discusses financing issues.

  13. Wind energy: A viable alternative

    International Nuclear Information System (INIS)

    Soin, R.S.

    1991-01-01

    This article examines the economic feasibility of wind energy in the current economic and political environment. The article specifically addresses the wind farm application to India, with asides to Europe and the US. Topics discussed include cost of energy generation for a 10 MW wind farm, cost comparison for captive energy options (diesel, coal, wind), environmental impacts, and social benefits

  14. Integrated Wind Power Planning Tool

    DEFF Research Database (Denmark)

    Rosgaard, Martin H.; Hahmann, Andrea N.; Nielsen, Torben S.

    This poster presents the Public Service Obligation (PSO) funded project PSO 10464 "Integrated Wind Power Planning Tool". The project goal is to integrate a Numerical Weather Prediction (NWP) model with statistical tools in order to assess wind power fluctuations, with focus on short term...... forecasting for existing wind farms, as well as long term power system planning for future wind farms....

  15. Wind energy utilization: A bibliography

    Science.gov (United States)

    1975-01-01

    Bibliography cites documents published to and including 1974 with abstracts and references, and is indexed by topic, author, organization, title, and keywords. Topics include: Wind Energy Potential and Economic Feasibility, Utilization, Wind Power Plants and Generators, Wind Machines, Wind Data and Properties, Energy Storage, and related topics.

  16. A FGGE water vapor wind data set

    Science.gov (United States)

    Stewart, Tod R.; Hayden, Christopher M.

    1985-01-01

    It has been recognized for some time that water vapor structure visible in infrared imagery offers a potential for obtaining motion vectors when several images are considered in sequence (Fischer et al., 1981). A study evaluating water vapor winds obtained from the VISSR atmospheric sounder (Stewart et al., 1985) has confirmed the viability of the approach. More recently, 20 data sets have been produced from METEOSAT water vapor imagery for the FGGE period of 10-25 November 1979. Where possible, two data sets were prepared for each day at 0000 and 1200 GMT and compared with rawinsondes over Europe, Africa, and aircraft observations over the oceans. Procedures for obtaining winds were, in general, similar to the earlier study. Motions were detected both by a single pixel tracking and a cross correlation method by using three images individually separated by one hour. A height assignment was determined by matching the measured brightness temperature to the temperature structure represented by the FGGE-IIIB analyses. Results show that the METEOSAT water vapor winds provide uniform horizontal coverage of mid-level flow over the globe with good accuracy.

  17. Wind flow through shrouded wind turbines

    Science.gov (United States)

    2017-03-01

    velocity and model angle were varied . Additionally, static wall pressures and cross section flow were studied with the addition of a screen. The pressure...the geometry of a wind lens or flange on the shroud and a gradually diverging shape, proved to accelerate the flow through the duct. 14. SUBJECT...Tunnel velocity and model angle were varied . Additionally, static wall pressures and cross section flow were studied with the addition of a screen. The

  18. Summertime wind climate in Yerevan: valley wind systems

    Science.gov (United States)

    Gevorgyan, Artur

    2017-03-01

    1992-2014 wind climatology analysis in Yerevan is presented with particular focus given to the summertime thermally induced valley wind systems. Persistence high winds are observed in Yerevan during July-August months when the study region is strongly affected by a heat-driven plain-plateau circulation. The local valley winds arrive in Yerevan in the evening hours, generally, from 1500 to 1800 UTC, leading to rapid enhancement of wind speeds and dramatic changes in wind direction. Valley-winds significantly impact the local climate of Yerevan, which is a densely populated city. These winds moderate evening temperatures after hot and dry weather conditions observed during summertime afternoons. On the other hand, valley winds result in significantly higher nocturnal temperatures and more frequent occurrence of warm nights (tn90p) in Yerevan due to stronger turbulent mixing of boundary layer preventing strong surface cooling and temperature drop in nighttime and morning hours. The applied WRF-ARW limited area model is able to simulate the key features of the observed spatial pattern of surface winds in Armenia associated with significant terrain channeling, wind curls, etc. By contrast, ECMWF EPS global model fails to capture mesoscale and local wind systems over Armenia. However, the results of statistical verification of surface winds in Yerevan showed that substantial biases are present in WRF 18-h wind forecasts, as well as, the temporal variability of observed surface winds is not reproduced adequately in WRF-ARW model.

  19. Wind energy handbook

    CERN Document Server

    Burton, Tony; Sharpe, David; Bossanyi, Ervin

    2011-01-01

    Named as one of Choice's Outstanding Academic Titles of 2012Every year, Choice subject editors recognise the most significant print and electronic works reviewed in Choice during the previous calendar year. Appearing annually inChoice's January issue, this prestigious list of publications reflects the best in scholarly titles and attracts extraordinary attention from the academic library community. The authoritative reference on wind energy, now fully revised and updated to include offshore wind power<

  20. Wind power barometer

    International Nuclear Information System (INIS)

    2006-01-01

    This annual evaluation is a synthesis of works published in 2006. Comparisons are presented between the wind power performances and European Commission White Paper and Biomass action plan objectives. Germany and Spain are no longer the only countries ensuring European Union market growth. The market sees also a rise in importance of wind power in United Kingdom, Portugal, Italy and France. (A.L.B.)

  1. Wind interviewet til politikken

    DEFF Research Database (Denmark)

    Wind, Marlene

    2017-01-01

    Fredag d. 29. september blev centerleder og professor ved Center for Europæisk Politik Marlene Wind interviewet til Politiken i forbindelse med det tyske forbundsvalgs betydning for EU's fremtid. Mange har spekuleret i om FDP (Freie Demokratische Partei) med deres unægtelige indflydelse på en...... kommende tysk koalition, kommer til at påvirke den tysk-franske alliance i EU-regi. Ikke hvis man spørger Marlene Wind:...

  2. Small wind turbine

    OpenAIRE

    Vélez Castellano, Didier

    2010-01-01

    The main objective is to develop a project on installing a small wind turbine at the University of Glyndwr in Wrexham Wales. Today are immersed in a world seeking clean energy for reduce greenhouse gases because this problem is becoming a global reality. So installing a small wind turbine at the university would provide large quantity of clean energy to supply a workshop and also reduce the expulsion of CO2 into the atmosphere. The main characteristic of the turbine under...

  3. Wind turbine state estimation

    OpenAIRE

    Knudsen, Torben

    2014-01-01

    Dynamic inflow is an effect which is normally not included in the models used for wind turbine control design. Therefore, potential improvement from including this effect exists. The objective in this project is to improve the methods previously developed for this and especially to verify the results using full-scale wind turbine data. The previously developed methods were based on extended Kalman filtering. This method has several drawback compared to unscented Kalman filtering which has the...

  4. Wind turbine reliability analysis

    OpenAIRE

    Pinar Pérez, Jesús María; García Márquez, Fausto Pedro; Tobias, Andrew Mark; Papaelias, Mayorkinos

    2013-01-01

    Against the background of steadily increasing wind power generation worldwide, wind turbine manufacturers are continuing to develop a range of configurations with different combinations of pitch control, rotor speeds, gearboxes, generators and converters. This paper categorizes the main designs, focusing on their reliability by bringing together and comparing data from a selection of major studies in the literature. These are not particularly consistent but plotting failure rates against hour...

  5. Wind Streak and Crater

    Science.gov (United States)

    2004-01-01

    23 February 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a wind streak developed in the lee of a meteor impact crater in western Daedalia Planum. The dominant winds responsible for the streak blew from the bottom/lower right (southeast). The image is located near 9.9oS, 144.9oW. Sunlight illuminates the scene from the lower left; the picture covers an area 3 km (1.9 mi) wide.

  6. Next Generation Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Cheraghi, S. Hossein [Western New England Univ., Springfield, MA (United States); Madden, Frank [FloDesign Wind Turbine Corp., Waltham, MA (United States)

    2012-09-01

    The goal of this collaborative effort between Western New England University's College of Engineering and FloDesign Wind Turbine (FDWT) Corporation to wok on a novel areodynamic concept that could potentially lead to the next generation of wind turbines. Analytical studies and early scale model tests of FDWT's Mixer/Ejector Wind Turbine (MEWT) concept, which exploits jet-age advanced fluid dynamics, indicate that the concept has the potential to significantly reduce the cost of electricity over conventional Horizontal Axis Wind Turbines while reducing land usage. This project involved the design, fabrication, and wind tunnel testing of components of MEWT to provide the research and engineering data necessary to validate the design iterations and optimize system performance. Based on these tests, a scale model prototype called Briza was designed, fabricated, installed and tested on a portable tower to investigate and improve the design system in real world conditions. The results of these scale prototype efforts were very promising and have contributed significantly to FDWT's ongoing development of a product scale wind turbine for deployment in multiple locations around the U.S. This research was mutually beneficial to Western New England University, FDWT, and the DOE by utilizing over 30 student interns and a number of faculty in all efforts. It brought real-world wind turbine experience into the classroom to further enhance the Green Engineering Program at WNEU. It also provided on-the-job training to many students, improving their future employment opportunities, while also providing valuable information to further advance FDWT's mixer-ejector wind turbine technology, creating opportunities for future project innovation and job creation.

  7. Database on Wind Characteristics

    DEFF Research Database (Denmark)

    Højstrup, J.; Ejsing Jørgensen, Hans; Lundtang Petersen, Erik

    1999-01-01

    his report describes the work and results of the project: Database on Wind Characteristics which was sponsered partly by the European Commision within the framework of JOULE III program under contract JOR3-CT95-0061......his report describes the work and results of the project: Database on Wind Characteristics which was sponsered partly by the European Commision within the framework of JOULE III program under contract JOR3-CT95-0061...

  8. Reliability Analysis of Wind Turbines

    DEFF Research Database (Denmark)

    Toft, Henrik Stensgaard; Sørensen, John Dalsgaard

    2008-01-01

    In order to minimise the total expected life-cycle costs of a wind turbine it is important to estimate the reliability level for all components in the wind turbine. This paper deals with reliability analysis for the tower and blades of onshore wind turbines placed in a wind farm. The limit states......) the reliability level for a wind turbine placed in a wind farm is considered, and wake effects from neighbouring wind turbines is taken into account. An illustrative example with calculation of the reliability for mudline bending of the tower is considered. In the example the design is determined according...

  9. Wind Conditions for Wind Farm Hanstholm

    DEFF Research Database (Denmark)

    Pena Diaz, Alfredo; Hahmann, Andrea N.; Mann, Jakob

    The net annual energy production (AEP) of the Hanstholm Wind Farm is 158 GWh per year for the Siemens SWT-3.6-120 turbine and 140 GWh for the Vestas V112-3.0 turbine. These values have an uncertainty (standard deviation) of 6%. This result is mainly based on the data for Risø DTU’s test station...... at Høvsøre where wind speeds are measured at approximately the same height as the turbines at Hanstholm and where the terrain is similar. On top of that meso-scale modeling has been used to extrapolate the climatology from Høvsøre to Hanstholm increasing the AEP by almost 6% compared to just using...... the Høvsøre climatology directly. This method of extrapolation is rather new, but several older investigations indicate that the wind resource at Hanstholm is slightly higher than at Høvsøre. The work is carried out for Grontmij-Carl Bro according to a contract dated January 18th 2011....

  10. WindPACT Reference Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Dykes, Katherine L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rinker, Jennifer [Former National Renewable Energy Laboratory (NREL) employee

    2018-04-02

    To fully understand how loads and turbine cost scale with turbine size, it is necessary to have identical turbine models that have been scaled to different rated powers. The report presents the WindPACT baseline models, which are a series of four baseline models that were designed to facilitate investigations into the scalings of loads and turbine cost with size. The models have four different rated powers (750 kW, 1.5 MW, 3.0 MW, and 5.0 MW), and each model was designed to its specified rated power using the same design methodology. The models were originally implemented in FAST_AD, the predecessor to NREL's open-source wind turbine simulator FAST, but have yet to be implemented in FAST. This report contains the specifications for all four WindPACT baseline models - including structural, aerodynamic, and control specifications - along with the inherent assumptions and equations that were used to calculate the model parameters. It is hoped that these baseline models will serve as extremely useful resources for investigations into the scalings of costs, loads, or optimization routines.

  11. Floating wind turbine system

    Science.gov (United States)

    Viterna, Larry A. (Inventor)

    2009-01-01

    A floating wind turbine system with a tower structure that includes at least one stability arm extending therefrom and that is anchored to the sea floor with a rotatable position retention device that facilitates deep water installations. Variable buoyancy for the wind turbine system is provided by buoyancy chambers that are integral to the tower itself as well as the stability arm. Pumps are included for adjusting the buoyancy as an aid in system transport, installation, repair and removal. The wind turbine rotor is located downwind of the tower structure to allow the wind turbine to follow the wind direction without an active yaw drive system. The support tower and stability arm structure is designed to balance tension in the tether with buoyancy, gravity and wind forces in such a way that the top of the support tower leans downwind, providing a large clearance between the support tower and the rotor blade tips. This large clearance facilitates the use of articulated rotor hubs to reduced damaging structural dynamic loads. Major components of the turbine can be assembled at the shore and transported to an offshore installation site.

  12. Wind turbines and health

    International Nuclear Information System (INIS)

    Rideout, K.; Copes, R.; Bos, C.

    2010-01-01

    This document summarized the potential health hazards associated with wind turbines, such as noise and low frequency sound, vibration and infrasound; electromagnetic fields (EMF); shadow flicker; and ice throw and structural failure. Various symptoms can be attributed to wind turbines, including dizziness, sleep disruption, and headaches. A review of available research regarding potential health affects to residents living in close proximity to wind turbines showed that the sound level associated with wind turbines at common residential setbacks is not sufficient to damage hearing, but may lead to annoyance and sleep disturbance. Research has shown that wind turbines are not a significant source of EMF exposure, and although shadows caused by the blades may be annoying, they are not likely to cause epileptic seizures at normal operational speeds. The risk of injury from ice throw can be minimized with setbacks of 200 to 400 m. Examples of Canadian wind turbine setback guidelines and regulations were also offered. It was concluded that setbacks and operational guidelines can be utilized in combination to address safety hazards, sound levels, land use issues, and impacts on people. 46 refs., 2 tabs., 2 figs.

  13. European wind turbine catalogue

    International Nuclear Information System (INIS)

    1994-01-01

    The THERMIE European Community programme is designed to promote the greater use of European technology and this catalogue contributes to the fulfillment of this aim by dissemination of information on 50 wind turbines from 30 manufacturers. These turbines are produced in Europe and are commercially available. The manufacturers presented produce and sell grid-connected turbines which have been officially approved in countries where this approval is acquired, however some of the wind turbines included in the catalogue have not been regarded as fully commercially available at the time of going to print. The entries, which are illustrated by colour photographs, give company profiles, concept descriptions, measured power curves, prices, and information on design and dimension, safety systems, stage of development, special characteristics, annual energy production, and noise pollution. Lists are given of wind turbine manufacturers and agents and of consultants and developers in the wind energy sector. Exchange rates used in the conversion of the prices of wind turbines are also given. Information can be found on the OPET network (organizations recognised by the European Commission as an Organization for the Promotion of Energy Technologies (OPET)). An article describes the development of the wind power industry during the last 10-15 years and another article on certification aims to give an overview of the most well-known and acknowledged type approvals currently issued in Europe. (AB)

  14. EDITORIAL: Wind energy

    Science.gov (United States)

    Mann, Jakob; Nørkær Sørensen, Jens; Morthorst, Poul-Erik

    2008-01-01

    Wind energy is rapidly growing. In 2006 the installed generating capacity in the world increased by 25%, a growth rate which has more or less been sustained during the last decade. And there is no reason to believe that this growth will slow significantly in the coming years. For example, the United Kingdom's goal for installed wind turbines by 2020 is 33 GW up from 2 GW in 2006, an average annual growth rate of 22% over that period. More than half of all turbines are installed in Europe, but United States, India and lately China are also rapidly growing markets. The cradle of modern wind energy was set by innovative blacksmiths in rural Denmark. Now the wind provides more than 20% of the electrical power in Denmark, the industry has professionalized and has close ties with public research at universities. This focus issue is concerned with research in wind energy. The main purposes of research in wind energy are to: decrease the cost of power generated by the wind; increase the reliability and predictability of the energy source; investigate and reduce the adverse environmental impact of massive deployment of wind turbines; build research based educations for wind energy engineers. This focus issue contains contributions from several fields of research. Decreased costs cover a very wide range of activities from aerodynamics of the wind turbine blades, optimal site selection for the turbines, optimization of the electrical grid and power market for a fluctuating source, more efficient electrical generators and gears, and new materials and production techniques for turbine manufacturing. The United Kingdom recently started the construction of the London Array, a 1 GW off-shore wind farm east of London consisting of several hundred turbines. To design such a farm optimally it is necessary to understand the chaotic and very turbulent flow downwind from a turbine, which decreases the power production and increases the mechanical loads on other nearby turbines. Also

  15. Wind turbines and health

    Energy Technology Data Exchange (ETDEWEB)

    Rideout, K.; Copes, R.; Bos, C. [National Colaborating Centre for Environmental Health, Vancouver, BC (Canada)

    2010-01-15

    This document summarized the potential health hazards associated with wind turbines, such as noise and low frequency sound, vibration and infrasound; electromagnetic fields (EMF); shadow flicker; and ice throw and structural failure. Various symptoms can be attributed to wind turbines, including dizziness, sleep disruption, and headaches. A review of available research regarding potential health affects to residents living in close proximity to wind turbines showed that the sound level associated with wind turbines at common residential setbacks is not sufficient to damage hearing, but may lead to annoyance and sleep disturbance. Research has shown that wind turbines are not a significant source of EMF exposure, and although shadows caused by the blades may be annoying, they are not likely to cause epileptic seizures at normal operational speeds. The risk of injury from ice throw can be minimized with setbacks of 200 to 400 m. Examples of Canadian wind turbine setback guidelines and regulations were also offered. It was concluded that setbacks and operational guidelines can be utilized in combination to address safety hazards, sound levels, land use issues, and impacts on people. 46 refs., 2 tabs., 2 figs.

  16. Tornado type wind turbines

    Science.gov (United States)

    Hsu, Cheng-Ting

    1984-01-01

    A tornado type wind turbine has a vertically disposed wind collecting tower with spaced apart inner and outer walls and a central bore. The upper end of the tower is open while the lower end of the structure is in communication with a wind intake chamber. An opening in the wind chamber is positioned over a turbine which is in driving communication with an electrical generator. An opening between the inner and outer walls at the lower end of the tower permits radially flowing air to enter the space between the inner and outer walls while a vertically disposed opening in the wind collecting tower permits tangentially flowing air to enter the central bore. A porous portion of the inner wall permits the radially flowing air to interact with the tangentially flowing air so as to create an intensified vortex flow which exits out of the top opening of the tower so as to create a low pressure core and thus draw air through the opening of the wind intake chamber so as to drive the turbine.

  17. The potential of wind farms

    International Nuclear Information System (INIS)

    Hauge Madsen, P.; Lundsager, P.

    1992-09-01

    Papers presented at the European wind energy conference on the potential of wind farms are presented. The aim of the conference was to bring into focus the problems, experiences and potential of the application of wind power in wind power farms as a contribution to the European and global energy supply. It was considered that the interchange of experience among representatives of science, utilities, industry, environment and energy planning, together with those who represent financial and insurance interests, would create a better understanding of all aspects of wind power for its future successful development. The subjects covered concern surveys of national planning and policies regarding wind energy utilization and national and global development of wind turbine arrays. The performance of some individual wind farms is described. Papers also deal with utility and project planning, wind prediction and certification, wind loads and fatigues, wakes, noise and control. (AB)

  18. The potential of wind farms

    International Nuclear Information System (INIS)

    Hauge Madsen, P.; Lundsager, P.

    1992-09-01

    Papers presented at the European wind energy conference on the potential of wind farms are presented. The aim of the conference was to bring into focus the problems, experiences and potential of the application of wind power in wind power farms as a contribution to the European and global energy supply. It was considered that the interchange of experience among representatives of science, utilities, industry, environment and energy planning, together with those who represent financial and insurance interests, would create a better understanding of all aspects of wind power for its future successful development. The subjects covered concern surveys of national planning and policies regarding wind energy utilization and national and global development of wind turbine arrays. The performance of some individual wind farms is described. Papers also deal with utility and project planning, wind prediction and certification, wind loads and fatigus, wakes, noise and control. (AB)

  19. Offshore wind farm repowering optimization

    DEFF Research Database (Denmark)

    Hou, Peng; Enevoldsen, Peter; Hu, Weihao

    2017-01-01

    is focused on optimization of offshore wind farm repowering, which is one option for the wind farm owner at end of life for the offshore wind farm. The LCoE is used as the evaluation index to identify whether it is economical to invest in such a way. In an optimized repowering strategy, different types...... of wind turbines are selected to replace the original wind turbines to reconstruct the wind farm, which is demonstrated to be better than the refurbishment approach which replaces the old wind turbines with the same type. The simulations performed in this research reveal that the reconstructed wind farm......, which consists of multiple types of wind turbine, has a smaller LCoE (10.43%) than the refurbishment approach, which shows the superiority of the proposed method. This research contributes an optimization tool to the wind industry, which consequently drives down the cost of energy produced by offshore...

  20. Coastal Ohio Wind Project

    Energy Technology Data Exchange (ETDEWEB)

    Gorsevski, Peter [Bowling Green State Univ., OH (United States); Afjeh, Abdollah [Univ. of Toledo, OH (United States); Jamali, Mohsin [Univ. of Toledo, OH (United States); Bingman, Verner [Bowling Green State Univ., OH (United States)

    2014-04-04

    The Coastal Ohio Wind Project intends to address problems that impede deployment of wind turbines in the coastal and offshore regions of Northern Ohio. The project evaluates different wind turbine designs and the potential impact of offshore turbines on migratory and resident birds by developing multidisciplinary research, which involves wildlife biology, electrical and mechanical engineering, and geospatial science. Firstly, the project conducts cost and performance studies of two- and three-blade wind turbines using a turbine design suited for the Great Lakes. The numerical studies comprised an analysis and evaluation of the annual energy production of two- and three-blade wind turbines to determine the levelized cost of energy. This task also involved wind tunnel studies of model wind turbines to quantify the wake flow field of upwind and downwind wind turbine-tower arrangements. The experimental work included a study of a scaled model of an offshore wind turbine platform in a water tunnel. The levelized cost of energy work consisted of the development and application of a cost model to predict the cost of energy produced by a wind turbine system placed offshore. The analysis found that a floating two-blade wind turbine presents the most cost effective alternative for the Great Lakes. The load effects studies showed that the two-blade wind turbine model experiences less torque under all IEC Standard design load cases considered. Other load effects did not show this trend and depending on the design load cases, the two-bladed wind turbine showed higher or lower load effects. The experimental studies of the wake were conducted using smoke flow visualization and hot wire anemometry. Flow visualization studies showed that in the downwind turbine configuration the wake flow was insensitive to the presence of the blade and was very similar to that of the tower alone. On the other hand, in the upwind turbine configuration, increasing the rotor blade angle of attack

  1. Sand Drift Potential by Wind in Shileh Plain of Sistan

    Directory of Open Access Journals (Sweden)

    S. Poormand

    2016-02-01

    directions from 1992 to 2003 in order to predict the volume of sand transportation and its direction using sand-rose and wind-rose softwares. As described earlier, in this research, the drift potential (DP is estimated for all possible wind speed categories, summed up for all categories of each direction sector using Fryberger’s Equation. The sand drift potential in Shileh was estimated about 3439 vector units with a resultant drift direction along the Southeast, which places it in the high class of wind erosive power based on the Fryberger and Dean (1979 classification method. The sand drift potential values show that the resultant drift direction is from the Northwest towards the Southeast. It was also found that the most powerful winds (the prevailing winds blow in the summer and the spring seasons, respectively. In contrast, the percentage of calm winds increases during autumn and winter times. The sand transport discharge was predicted to be 20.422 t m-1 year-1 using Lattau and Lattau Equation. With regard to the monthly sand rose, it was seen that the resultant drift potential was low in December and January and high in June and July. The prevailing wind direction ranged from North to Northwest in all seasons. The winds with the highest velocities were observed in the summer, while the winds with lower velocities were observed during the winter. Wind velocities higher than 11 m s-1 had the largest frequencies in the summer and the lowest frequencies in the winter. Wind unidirectional index (UDI is estimated to be 0.95, implying that the index provides a suitable condition for the creation of transverse (barchanoid dunes. Conclusion: The Sistan plain is one of the windiest places in the world that is exposed to wind erosion and dust storms. The result of this study is very important due to the construction of an international roadway that connects Chabahar port to Sistan plain and continues towards the Afghanistan border. Therefore, the practical result of this

  2. Wind direction variability in Afternoon and Sunset Turbulence

    Science.gov (United States)

    Nilsson, Erik; Lothon, Marie; Lohou, Fabienne; Mahrt, Larry

    2014-05-01

    Understanding wind direction (WD) variability better is important for several reasons. Air pollution models need information about how variable wind direction is in different conditions (Davies and Thomson 1999). Accurate predictions of dispersion are important for human health and safety and allow for adaptation planning (Nagle et al. 2011). Other applications include horizontal diffusion, efficiency and fatigue of wind machines and air-sea interaction (Mahrt 2011). Most studies of wind direction variability have focused on nocturnal conditions because of greater variability in light winds. Modelling WD variability in transition periods when both mean wind speed and variance of the wind components are in a state of change can, however, also be very challenging and has not been the focus of earlier studies. The evening transitioning to the nocturnal boundary layer can play an important role in the diffusion process of pollutants and scalars emitted at surface and transported within the atmosphere. The Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) field campaign that took place in southern France in June and July 2011 focused on the decaying turbulence of the late afternoon boundary layer and related issues (Lothon et al. 2012). We analyse field measurements from BLLAST to investigate WD variability in the evening transition period. Standard deviations of horizontal wind direction fluctuations in the lowest 60 m of the boundary layer have been examined for dependence on mean wind speed, higher order moments and averaging time. Measurement results are interpreted using measured and idealized probability density functions of horizontal wind vectors. These are also used to develop analytical functions describing how WD variability depends on wind speed, variance and other controlling factors in the atmospheric boundary layer. References: Davies B.M., Thomson D.J., 1999. Comparison of some parameterizations of wind direction variability with observations

  3. Intermittent structures at ion scales in the turbulent solar wind

    Science.gov (United States)

    Perrone, Denise; Alexandrova, Olga; Lion, Sonny; Roberts, Owen W.; Maksimovic, Milan; Escoubet, Philippe C.; Zouganelis, Yannis

    2017-04-01

    Understanding the physical mechanisms of dissipation, and the related heating, in turbulent collisionless plasmas (such as the solar wind) represents nowadays one of the key issues of plasma physics. Although the complex behavior of the solar wind has been matter of investigation of many years, some of the primary problems still remain a puzzle for the scientific community. Here, we study coherent structures responsible for solar wind intermittency around ion characteristic scales. We find that, in fast solar wind, intermittency is due to current sheets and Alfvén vortex-like structures. In slow solar wind, we observe as well compressive structures like magnetic solitons, holes and shocks. By using high-time resolution magnetic field data of multi-point measurements of Cluster spacecraft, we characterize the observed coherent structures in terms of topology and propagation speed. We show that all structures, both in fast and slow solar wind, are characterized by a strong wave-vector anisotropy in the perpendicular direction with respect to the local magnetic field and typical scales around ion characteristic scales. Moreover, some of them propagate in the plasma rest frame. Moreover, a further analysis on the ion velocity distribution shows a high variability; in particular, close to coherent structures the proton distribution function appears strongly deformed and far from the thermodynamic equilibrium. We discuss possible interpretation of the observed structures and their role in the heating process of the plasma.

  4. Modelling of a PMSG Wind Turbine with Autonomous Control

    Directory of Open Access Journals (Sweden)

    Chia-Nan Wang

    2014-01-01

    Full Text Available The aim of this research is to model an autonomous control wind turbine driven permanent magnetic synchronous generator (PMSG which feeds alternating current (AC power to the utility grid. Furthermore, this research also demonstrates the effects and the efficiency of PMSG wind turbine which is integrated by autonomous controllers. In order for well autonomous control, two voltage source inverters are used to control wind turbine connecting with the grid. The generator-side inverter is used to adjust the synchronous generator as well as separating the generator from the grid when necessary. The grid-side inverter controls the power flow between the direct current (DC bus and the AC side. Both of them are oriented control by space vector pulse width modulation (PWM with back-to-back frequency inverter. Moreover, the proportional-integral (PI controller is enhanced to control both of the inverters and the pitch angle of the wind turbine. Maximum power point tracking (MPPT is integrated in generator-side inverter to track the maximum power, when wind speed changes. The simulation results in Matlab Simulink 2012b showing the model have good dynamic and static performance. The maximum power can be tracked and the generator wind turbine can be operated with high efficiency.

  5. Wind turbine control and monitoring

    CERN Document Server

    Luo, Ningsu; Acho, Leonardo

    2014-01-01

    Maximizing reader insights into the latest technical developments and trends involving wind turbine control and monitoring, fault diagnosis, and wind power systems, 'Wind Turbine Control and Monitoring' presents an accessible and straightforward introduction to wind turbines, but also includes an in-depth analysis incorporating illustrations, tables and examples on how to use wind turbine modeling and simulation software.   Featuring analysis from leading experts and researchers in the field, the book provides new understanding, methodologies and algorithms of control and monitoring, comput

  6. Wind Energy Workforce Development & Jobs

    Energy Technology Data Exchange (ETDEWEB)

    Tegen, Suzanne

    2016-11-08

    The United States needs a skilled and qualified wind energy workforce to produce domestic clean power. To assist with wind energy workforce development, the U.S. Department of Energy (DOE) and National Renewable Energy Laboratory are engaged with several efforts.This presentation by Suzanne Tegen describes these efforts, including a wind industry survey, DOE's Wind Career Map, the DOE Wind Vision report, and an in-depth discussion of the Jobs & Economic Development Impacts Model.

  7. Small Wind Site Assessment Guidelines

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, Tim [Advanced Energy Systems LLC, Eugene, OR (United States); Preus, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-09-01

    Site assessment for small wind energy systems is one of the key factors in the successful installation, operation, and performance of a small wind turbine. A proper site assessment is a difficult process that includes wind resource assessment and the evaluation of site characteristics. These guidelines address many of the relevant parts of a site assessment with an emphasis on wind resource assessment, using methods other than on-site data collection and creating a small wind site assessment report.

  8. Performance of spanish wind turbines

    International Nuclear Information System (INIS)

    Lago, C.

    1995-01-01

    In this document we can find a statistical evaluation for the wind energy generation from each spanish wind farm referred to 1994, going on with the work that has been carried out since 1992, by initiative of the Wind Energy Division from Renewable Energy Institute. The purpose of this work is to contribute with interesting information for the wind environment and offer a global view from monthly performances of different wind farms. (Author)

  9. Toward lattice fractional vector calculus

    Science.gov (United States)

    Tarasov, Vasily E.

    2014-09-01

    An analog of fractional vector calculus for physical lattice models is suggested. We use an approach based on the models of three-dimensional lattices with long-range inter-particle interactions. The lattice analogs of fractional partial derivatives are represented by kernels of lattice long-range interactions, where the Fourier series transformations of these kernels have a power-law form with respect to wave vector components. In the continuum limit, these lattice partial derivatives give derivatives of non-integer order with respect to coordinates. In the three-dimensional description of the non-local continuum, the fractional differential operators have the form of fractional partial derivatives of the Riesz type. As examples of the applications of the suggested lattice fractional vector calculus, we give lattice models with long-range interactions for the fractional Maxwell equations of non-local continuous media and for the fractional generalization of the Mindlin and Aifantis continuum models of gradient elasticity.

  10. Gauge Theories of Vector Particles

    Science.gov (United States)

    Glashow, S. L.; Gell-Mann, M.

    1961-04-24

    The possibility of generalizing the Yang-Mills trick is examined. Thus we seek theories of vector bosons invariant under continuous groups of coordinate-dependent linear transformations. All such theories may be expressed as superpositions of certain "simple" theories; we show that each "simple theory is associated with a simple Lie algebra. We may introduce mass terms for the vector bosons at the price of destroying the gauge-invariance for coordinate-dependent gauge functions. The theories corresponding to three particular simple Lie algebras - those which admit precisely two commuting quantum numbers - are examined in some detail as examples. One of them might play a role in the physics of the strong interactions if there is an underlying super-symmetry, transcending charge independence, that is badly broken. The intermediate vector boson theory of weak interactions is discussed also. The so-called "schizon" model cannot be made to conform to the requirements of partial gauge-invariance.

  11. Introduction to vector velocity imaging

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Udesen, Jesper; Hansen, Kristoffer Lindskov

    it virtually impossible to compensate for the factor and obtain correct velocity estimates for either CFM or spectral velocity estimation. This talk will describe methods for finding the correct velocity by estimating both the axial and lateral component of the velocity vector. The transverse oscillation...... method introduces an ultrasound field that oscillation not only along the ultrasound beam both also transverse to it to estimate both the lateral and axial velocity for the full velocity vector. The correct velocity magnitude can be found from this as well as the instantaneous angle. This can be obtained...... over the full region of interest and a real time image at a frame rate of 20 Hz can be displayed. Real time videos have been obtained from both our research systems and from commercial BK Medical scanners. The vector velocity images reveal the full complexity of the human blood flow. It is easy to see...

  12. 3D vector flow imaging

    DEFF Research Database (Denmark)

    Pihl, Michael Johannes

    The main purpose of this PhD project is to develop an ultrasonic method for 3D vector flow imaging. The motivation is to advance the field of velocity estimation in ultrasound, which plays an important role in the clinic. The velocity of blood has components in all three spatial dimensions, yet...... conventional methods can estimate only the axial component. Several approaches for 3D vector velocity estimation have been suggested, but none of these methods have so far produced convincing in vivo results nor have they been adopted by commercial manufacturers. The basis for this project is the Transverse...... on the TO fields are suggested. They can be used to optimize the TO method. In the third part, a TO method for 3D vector velocity estimation is proposed. It employs a 2D phased array transducer and decouples the velocity estimation into three velocity components, which are estimated simultaneously based on 5...

  13. Topological vector spaces and distributions

    CERN Document Server

    Horvath, John

    2012-01-01

    ""The most readable introduction to the theory of vector spaces available in English and possibly any other language.""-J. L. B. Cooper, MathSciNet ReviewMathematically rigorous but user-friendly, this classic treatise discusses major modern contributions to the field of topological vector spaces. The self-contained treatment includes complete proofs for all necessary results from algebra and topology. Suitable for undergraduate mathematics majors with a background in advanced calculus, this volume will also assist professional mathematicians, physicists, and engineers.The precise exposition o

  14. Synthetic Aperture Vector Flow Imaging

    DEFF Research Database (Denmark)

    Villagómez Hoyos, Carlos Armando

    The main objective of this project was to continue the development of a synthetic aperture vector flow estimator. This type of estimator is capable of overcoming two of the major limitations in conventional ultrasound systems: 1) the inability to scan large region of interest with high temporal......, this thesis showed that novel information can be obtained with vector velocity methods providing quantitative estimates of blood flow and insight into the complexity of the hemodynamics dynamics. This could give the clinician a new tool in assessment and treatment of a broad range of diseases....

  15. Generation of arbitrary vector beams

    Science.gov (United States)

    Perez-Garcia, Benjamin; López-Mariscal, Carlos; Hernandez-Aranda, Raul I.; Gutiérrez-Vega, Julio C.

    2017-08-01

    Optical vector beams arise from point to point spatial variations of the electric component of an electromagnetic field over the transverse plane. In this work, we present a novel experimental technique to generate arbitrary vec- tor beams, and provide sufficient evidence to validate their state of polarization. This technique takes advantage of the capability of a Spatial Light Modulator to simultaneously generate two components of an electromagnetic field by halving the screen of the device and subsequently recombining them in a Sagnac interferometer. Our experimental results show the versatility and robustness of this technique for the generation of vector beams.

  16. Learning with Support Vector Machines

    CERN Document Server

    Campbell, Colin

    2010-01-01

    Support Vectors Machines have become a well established tool within machine learning. They work well in practice and have now been used across a wide range of applications from recognizing hand-written digits, to face identification, text categorisation, bioinformatics, and database marketing. In this book we give an introductory overview of this subject. We start with a simple Support Vector Machine for performing binary classification before considering multi-class classification and learning in the presence of noise. We show that this framework can be extended to many other scenarios such a

  17. Wind Atlas of Bay of Bengal with Satellite Wind Measurement

    DEFF Research Database (Denmark)

    Nadi, Navila Rahman

    footstep towards offshore wind energy analysis for this region. Generally, it is difficult to find offshore wind data relative to the wind turbine hub heights, therefore a starting point is necessary to identify the possible wind power density of the region. In such scenario, Synthetic aperture radars (SAR......The objective of this study is to obtain appropriate offshore location in the Bay of Bengal, Bangladesh for further development of wind energy. Through analyzing the previous published works, no offshore wind energy estimation has been found here. That is why, this study can be claimed as the first......) have proven useful. In this study, SAR based dataset- ENVISAT ASAR has been used for Wind Atlas generation. Furthermore, a comparative study has been performed with Global Wind Atlas (GWA) to determine a potential offshore wind farm. Additionally, the annual energy production of that offshore windfarm...

  18. Wind power today: 1999 Wind Energy program highlights

    Energy Technology Data Exchange (ETDEWEB)

    Weis-Taylor, Pat

    2000-04-06

    Wind Power Today is an annual publication that provides an overview for the Department of Energy's Wind Energy Program. The purpose of Wind Power Today is to show how DOE's Wind Energy Program supports wind turbine research and deployment in hopes of furthering the advancement of wind technologies that produce clean, low-cost, reliable energy for the 21st century. Content objectives include: Educate readers about the advantages and potential for widespread deployment of wind energy; explain DOE wind energy program objectives and goals; describe program accomplishments in research and application; examine the barriers to widespread deployment; describe benefits of continued research and development; facilitate technology transfer; attract cooperative wind energy projects with industry.

  19. When real life wind speed exceeds design wind assumptions

    Energy Technology Data Exchange (ETDEWEB)

    Winther-Jensen, M.; Joergensen, E.R. [Risoe National Lab., Roskilde (Denmark)

    1999-03-01

    Most modern wind turbines are designed according to a standard or a set of standards to withstand the design loads with a defined survival probability. Mainly the loads are given by the wind conditions on the site defining the `design wind speeds`, normally including extreme wind speeds given as an average and a peak value. The extreme wind speeds are normally (e.g. in the upcoming IEC standard for wind turbine safety) defined as having a 50-year recurrence period. But what happens when the 100 or 10,000 year wind situation hits a wind turbine? Results on wind turbines of wind speeds higher than the extreme design wind speeds are presented based on experiences especially from the State of Gujarat in India. A description of the normal approach of designing wind turbines in accordance with the standards in briefly given in this paper with special focus on limitations and built-in safety levels. Based on that, other possibilities than just accepting damages on wind turbines exposed for higher than design wind speeds are mentioned and discussed. The presentation does not intend to give the final answer to this problem but is meant as an input to further investigations and discussions. (au)

  20. Evaluation of wind farm efficiency and wind turbine wakes at the Nysted offshore wind farm

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Jensen, L.E.

    2010-01-01

    be quantified, albeit with relatively large uncertainty due to stochastic effects in the data. There is evidence of the ‘deep array effect’ in that wake losses in the centre of the wind farm are under-estimated by the wind farm model WAsP, although overall efficiency of the wind farm is well predicted due......Here, we quantify relationships between wind farm efficiency and wind speed, direction, turbulence and atmospheric stability using power output from the large offshore wind farm at Nysted in Denmark. Wake losses are, as expected, most strongly related to wind speed variations through the turbine...... thrust coefficient; with direction, atmospheric stability and turbulence as important second order effects. While the wind farm efficiency is highly dependent on the distribution of wind speeds and wind direction, it is shown that the impact of turbine spacing on wake losses and turbine efficiency can...

  1. Wind turbine storage systems

    International Nuclear Information System (INIS)

    Ibrahim, H.; Ilinca, A.; Perron, J.

    2005-01-01

    Electric power is often produced in locations far from the point of utilization which creates a challenge in stabilizing power grids, particularly since electricity cannot be stored. The production of decentralized electricity by renewable energy sources offers a greater security of supply while protecting the environment. Wind power holds the greatest promise in terms of environmental protection, competitiveness and possible applications. It is known that wind energy production is not always in phase with power needs because of the uncertainty of wind. For that reason, energy storage is the key for the widespread integration of wind energy into the power grids. This paper proposed various energy storage methods that can be used in combination with decentralized wind energy production where an imbalance exists between electricity production and consumption. Energy storage can play an essential role in bringing value to wind energy, particularly if electricity is to be delivered during peak hours. Various types of energy storage are already in use or are being developed. This paper identified the main characteristics of various electricity storage techniques and their applications. They include stationary or embarked storage for long or short term applications. A comparison of characteristics made it possible to determine which types of electricity storage are best suited for wind energy. These include gravity energy; thermal energy; compressed air energy; coupled storage with natural gas; coupled storage with liquefied gas; hydrogen storage for fuel cells; chemical energy storage; storage in REDOX batteries; storage by superconductive inductance; storage in supercondensers; and, storage as kinetic energy. 21 refs., 21 figs

  2. Wind Power Today: 1998 Wind Energy Program Highlights

    Energy Technology Data Exchange (ETDEWEB)

    Tromly, K.

    1999-06-17

    The US Department of Energy's Office of Energy Efficiency and Renewable Energy manages the Federal Wind Energy Program. The mission of the program is to help the US wind industry to complete the research, testing, and field verification needed to fully develop advanced wind technologies that will lead the world in cost-effectiveness and reliability. This publication, printed annually, provides a summary of significant achievements in wind energy made during the previous calendar year. Articles include wind energy in the Midwest, an Alaskan wind energy project, the US certification program, structural testing, and the federal program in review.

  3. The Wind Integration National Dataset (WIND) toolkit (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Caroline Draxl: NREL

    2014-01-01

    Regional wind integration studies require detailed wind power output data at many locations to perform simulations of how the power system will operate under high penetration scenarios. The wind datasets that serve as inputs into the study must realistically reflect the ramping characteristics, spatial and temporal correlations, and capacity factors of the simulated wind plants, as well as being time synchronized with available load profiles.As described in this presentation, the WIND Toolkit fulfills these requirements by providing a state-of-the-art national (US) wind resource, power production and forecast dataset.

  4. Wind power production: from the characterisation of the wind resource to wind turbine technologies

    International Nuclear Information System (INIS)

    Beslin, Guy; Multon, Bernard

    2016-01-01

    Illustrated by graphs and tables, this article first describes the various factors and means related to the assessment of wind resource in the World, in Europe, and the factors which characterize a local wind resource. In this last respect, the authors indicate how local topography is taken into account to calculate wind speed, how time variations are taken into account (at the yearly, seasonal or daily level), the different methods used to model a local wind resource, how to assess the power recoverable by a wind turbine with horizontal axis (notion of Betz limit). In the second part, the authors present the different wind turbines, their benefits and drawbacks: vertical axis, horizontal axis (examples of a Danish-type wind turbine, of wind turbines designed for extreme conditions). Then, they address the technology of big wind turbines: evolution of technology and of commercial offer, aerodynamic characteristics of wind turbine and benefit of a varying speed (technological solutions, importance of the electric generator). They describe how to choose a wind turbine, how product lines are organised, how the power curve and energy capacity are determined. The issue of integration of wind energy into the power system is then addressed. The next part addressed the economy of wind energy production (annualized production cost, order of magnitude of wind electric power production cost). Future trends are discussed and offshore wind energy production is briefly addressed

  5. Aeroservoelasticity of wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Skovmose Kallesoee, B.

    2007-12-14

    This thesis deals with the fundamental aeroelastic interaction between structural motion, Pitch action and control for a wind turbine blade. As wind turbines become larger, the interaction between pitch action, blade motion, aerodynamic forces, and control become even more important to understand and address. The main contribution of this thesis is the development of an aeroelastic blade model which on the one hand includes the important effects of steady state blade deformation, gravity and pitch action, and on the other it is transparent, suitable for analytical analysis and parameter studies, and furthermore linear and therefore suitable for control design. The development of the primary aeroelastic blade model is divided into four steps: 1) Nonlinear partial differential equations (PDEs) of structural blade motion are derived together with equations of pitch action and rotor speed; the individual terms in these equations are discussed and given physical interpretations; 2) Steady state blade deformation and induced velocities are computed by combining the PDEs with a steady state aerodynamic model; 3) Aeroelastic modes of motion are computed by combining the linearized PDEs with a linear unsteady aerodynamic model; this model is used to analyze how blade deformation effects the modes of motion; and 4) the linear aeroelastic blade model is derived by a modal expansion of the linearized PDEs combined with a linear unsteady aerodynamic model. The aeroelastic blade model has many similarities to a 2D blade section model, and it can be used instead of this in many applications, giving a transparent connection to a real wind turbine blade. In this work the aeroelastic blade model is used to analyze interaction between pitch action, blade motion and wind speed variations. Furthermore the model is used to develop a state estimator for estimating the wind speed and wind shear, and to suggest a load reducing controller. The state estimator estimates the wind shear very

  6. Wind Farms: Modeling and Control

    DEFF Research Database (Denmark)

    Soleimanzadeh, Maryam

    2012-01-01

    is minimized. The controller is practically feasible. Yet, the results on load reduction in this approach are not very significant. In the second strategy, the wind farm control problem has been divided into below rated and above rated wind speed conditions. In the above rated wind speed pitch angle and power....... Distributed controller design commences with formulating the problem, where a structured matrix approach has been put in to practice. Afterwards, an H2 control problem is implemented to obtain the controller dynamics for a wind farm such that the structural loads on wind turbines are minimized.......The primary purpose of this work is to develop control algorithms for wind farms to optimize the power production and augment the lifetime of wind turbines in wind farms. In this regard, a dynamical model for wind farms was required to be the basis of the controller design. In the first stage...

  7. Wind energy potential in India

    International Nuclear Information System (INIS)

    Rangarajan, S.

    1995-01-01

    Though located in the tropics, India is endowed with substantial wind resources because of its unique geographical location which gets fully exposed to both the south-west and north-east monsoon winds. The westerly winds of the south-west monsoons provide bulk of the wind potential. Areas with mean annual wind speed exceeding 18 k mph and areas with mean annual power density greater than 140 W/m 2 have been identified using the wind data collected by the wind monitoring project funded by the Ministry of Non-conventional Energy Sources (MNES). Seasonal variations in wind speed at selected locations are discussed as also the frequency distribution of hourly wind speed. Annual capacity factors for 250 kW wind electric generators have been calculated for several typical locations. A good linear correlation has been found between mean annual wind speed and mean annual capacity factor. A method is described for assessing wind potential over an extended region where adequate data is available. It is shown that the combined wind energy potential over five selected areas of limited extent in Gujarat, Andhra Pradesh and Tamil Nadu alone amounts to 22,000 MW under the assumption of 20 per cent land availability for installing wind farms. For a higher percentage of land availability, the potential will be correspondingly higher. (author). 12 refs., 6 figs., 3 tabs

  8. The consequences of poor vectorization

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    This talk briefly discusses the vectorization problem and how it impacts scientific and engineering systems. A simple cost model of designing such system in context of different phases of software lifetime is considered. Finally a concept for scalable solution is presented.

  9. Parallel Sparse Matrix - Vector Product

    DEFF Research Database (Denmark)

    Alexandersen, Joe; Lazarov, Boyan Stefanov; Dammann, Bernd

    This technical report contains a case study of a sparse matrix-vector product routine, implemented for parallel execution on a compute cluster with both pure MPI and hybrid MPI-OpenMP solutions. C++ classes for sparse data types were developed and the report shows how these class can be used...

  10. Phlebotomine Vectors of Human Disease.

    Science.gov (United States)

    1983-12-30

    different. We refrain from naming this specimen until more material becomes available. 12. Lutzomyia olmeca bicolor Fairchild and Theodor 1971...Castillo (1958) and Arzube (1960). Lutzomyia olmeca bicolor is the suspected vector of Leishmania mexicana aristedesi among rodents and marsupials in

  11. Scalar Calibration of Vector Magnetometers

    DEFF Research Database (Denmark)

    Merayo, José M.G.; Brauer, Peter; Primdahl, Fritz

    2000-01-01

    The calibration parameters of a vector magnetometer are estimated only by the use of a scalar reference magnetometer. The method presented in this paper differs from those previously reported in its linearized parametrization. This allows the determination of three offsets or signals in the absence...

  12. Vector-meson dominance revisited

    Directory of Open Access Journals (Sweden)

    Terschlüsen Carla

    2012-12-01

    Full Text Available The interaction of mesons with electromagnetism is often well described by the concept of vector-meson dominance (VMD. However, there are also examples where VMD fails. A simple chiral Lagrangian for pions, rho and omega mesons is presented which can account for the respective agreement and disagreement between VMD and phenomenology in the sector of light mesons.

  13. Vector fields on nonorientable surfaces

    Directory of Open Access Journals (Sweden)

    Ilie Barza

    2003-01-01

    X, and the space of vector fields on X are proved by using a symmetrisation process. An example related to the normal derivative on the border of the Möbius strip supports the nontriviality of the concepts introduced in this paper.

  14. Portfolio Analysis for Vector Calculus

    Science.gov (United States)

    Kaplan, Samuel R.

    2015-01-01

    Classic stock portfolio analysis provides an applied context for Lagrange multipliers that undergraduate students appreciate. Although modern methods of portfolio analysis are beyond the scope of vector calculus, classic methods reinforce the utility of this material. This paper discusses how to introduce classic stock portfolio analysis in a…

  15. Vector ecology of equine piroplasmosis

    Science.gov (United States)

    Equine piroplasmosis (EP) is a disease of equidae including horses, donkeys, mules and zebras caused by either of two protozoan parasites, Theileria equi or Babesia caballi. These parasites are biologically transmitted between hosts via tick-vectors and although they have inherent differences, they ...

  16. Wind power barometer

    International Nuclear Information System (INIS)

    Anon.

    2010-01-01

    The global wind power market not only repelled the strictures of the financial crisis, but saw the installation of 37 GW in 2009, which is almost 10 GW up on 2008. China and the United States registered particularly steady growth and the European Union also picked up momentum to break its installation record. A total capacity of 158 GW of wind power are now installed across the world from which 74.8 GW in the European Union. Among the European countries Denmark has the highest wind capacity per inhabitant in 2009: 627.5 kW/1000 inhabitants. Spain seeks to limit its market's growth in order to better manage the development of wind energy across the country. German growth is back, Italy chalks up a new record for installation and the French market is becoming increasingly regulated. United-Kingdom is developing offshore wind farms: the offshore capacity could reasonably rise to 20000 MW by 2020. The last part of the article reports some economical news from the leading players: Vestas, GE-Energy, Gamesa, Enercon, Sinovel and Siemens. (A.C.)

  17. Wind Powering America

    International Nuclear Information System (INIS)

    Flowers, L.; Dougherty, P. J.

    2001-01-01

    At the June 1999 Windpower Conference, the Secretary of Energy launched the Office of Energy Efficiency and Renewable Energy's Wind Powering America (WPA) initiative. The goals of the initiative are to meet 5% of the nation's energy needs with wind energy by 2020 (i.e., 80,000 megawatts installed), to double the number of states that have more than 20 megawatts (MW) of wind capacity to 16 by 2005 and triple it to 24 by 2010, and to increase wind's contribution to Federal electricity use to 5% by 2010. To achieve the Federal government's goal, DOE would take the leadership position and work with its Federal partners. Subsequently, the Secretary accelerated the DOE 5% commitment to 2005. Achieving the 80,000 MW goal would result in approximately$60 billion investment and$1.5 billion of economic development in our rural areas (where the wind resources are the greatest). The purpose of this paper is to provide an update on DOE's strategy for achieving its goals and the activities it has undertaken since the initiative was announced

  18. Wind Powering America

    Energy Technology Data Exchange (ETDEWEB)

    Flowers, L. (NREL); Dougherty, P. J. (DOE)

    2001-07-07

    At the June 1999 Windpower Conference, the Secretary of Energy launched the Office of Energy Efficiency and Renewable Energy's Wind Powering America (WPA) initiative. The goals of the initiative are to meet 5% of the nation's energy needs with wind energy by 2020 (i.e., 80,000 megawatts installed), to double the number of states that have more than 20 megawatts (MW) of wind capacity to 16 by 2005 and triple it to 24 by 2010, and to increase wind's contribution to Federal electricity use to 5% by 2010. To achieve the Federal government's goal, DOE would take the leadership position and work with its Federal partners. Subsequently, the Secretary accelerated the DOE 5% commitment to 2005. Achieving the 80,000 MW goal would result in approximately $60 billion investment and $1.5 billion of economic development in our rural areas (where the wind resources are the greatest). The purpose of this paper is to provide an update on DOE's strategy for achieving its goals and the activities it has undertaken since the initiative was announced.

  19. Wind turbine noise diagnostics

    International Nuclear Information System (INIS)

    Richarz, W.; Richarz, H.

    2009-01-01

    This presentation proposed a self-consistent model for broad-band noise emitted from modern wind turbines. The simple source model was consistent with the physics of sound generation and considered the unique features of wind turbines. Although the acoustics of wind turbines are similar to those of conventional propellers, the dimensions of wind turbines pose unique challenges in diagnosing noise emission. The general features of the sound field were deduced. Source motion and source directivity appear to be responsible for amplitude variations. The amplitude modulation is likely to make wind-turbine noise more audible, and may be partly responsible for annoyance that has been reported in the literature. Acoustic array data suggests that broad-band noise is emitted predominantly during the downward sweep of each rotor blade. Source motion and source directivity account for the observed pattern. Rotor-tower interaction effects are of lesser importance. Predicted amplitude modulation ranges from 1 dB to 6dB. 2 refs., 9 figs.

  20. Wind energy and Turkey.

    Science.gov (United States)

    Coskun, Aynur Aydin; Türker, Yavuz Özhan

    2012-03-01

    The global energy requirement for sustaining economic activities, meeting social needs and social development is increasing daily. Environmentally friendly, renewable energy resources are an alternative to the primary non-renewable energy resources, which devastate ecosystems in order to meet increasing demand. Among renewable energy sources such as hydropower, biopower, geothermal power and solar power, wind power offers distinct advantages to Turkey. There is an increasing tendency toward wind globally and the European Union adjusted its legal regulations in this regard. As a potential EU Member state, Turkey is going through a similar process. The number of institutional and legal regulations concerning wind power has increased in recent years; technical infrastructure studies were completed, and some important steps were taken in this regard. This study examines the way in which Turkey has developed support for wind power, presents a SWOT analysis of the wind power sector in Turkey and a projection was made for the concrete success expected to be accomplished in the future.