WorldWideScience

Sample records for altamont pass wind

  1. Bird Mortaility at the Altamont Pass Wind Resource Area: March 1998--September 2001

    Energy Technology Data Exchange (ETDEWEB)

    Smallwood, K. S.; Thelander, C. G.

    2005-09-01

    Over the past 15 years, research has shown that wind turbines in the Altamont Pass Wind Resource Area (APWRA) kill many birds, including raptors, which are protected by the Migratory Bird Treaty Act (MBTA), the Bald and Golden Eagle Protection Act, and/or state and federal Endangered Species Acts. Early research in the APWRA on avian mortality mainly attempted to identify the extent of the problem. In 1998, however, the National Renewable Energy Laboratory (NREL) initiated research to address the causal relationships between wind turbines and bird mortality. NREL funded a project by BioResource Consultants to perform this research directed at identifying and addressing the causes of mortality of various bird species from wind turbines in the APWRA.With 580 megawatts (MW) of installed wind turbine generating capacity in the APWRA, wind turbines there provide up to 1 billion kilowatt-hours (kWh) of emissions-free electricity annually. By identifying and implementing new methods and technologies to reduce or resolve bird mortality in the APWRA, power producers may be able to increase wind turbine electricity production at the site and apply similar mortality-reduction methods at other sites around the state and country.

  2. A Population Study of Golden Eagles in the Altamont Pass Wind Resource Area: Population Trend Analysis, 1994-1997

    International Nuclear Information System (INIS)

    The wind industry has annually reported 28-43 turbine blade strike casualties of golden eagles in the Altamont Pass Wind Resource Area, and many more carcasses have doubtless gone unnoticed. Because this species is especially sensitive to adult survival rate changes, we focused upon estimating the demographic trend of the population. In aerial surveys, we monitored survival within a sample of 179 radio-tagged eagles over a four-year period. We also obtained data on territory occupancy and reproduction of about 65 eagle pairs residing in the area. Of 61 recorded deaths of radio-tagged eagles during the four-year investigation, 23 (38%) were caused by wind turbine blade strikes. Additional fatalities were unrecorded because blade strikes sometimes destroy radio transmitters. Annual survival was estimated at 0.7867 (SE=0.0263) for non-territorial eagles and 0.8964 (SE=0.0371) for territorial ones. Annual reproduction was 0.64 (SE=0.08) young per territorial pair (0.25 per female). These parameters were used to estimate population growth rates under different modeling frameworks. At present, there are indications that a reserve of non-breeding adults still exists, i.e., there is an annual territorial re-occupancy rate of 100% and a low incidence (3%) of sub-adults as members of breeding pairs

  3. Response of Red-Tailed Hawks and Golden Eagles to Topographical Features, Weather, and Abundance of a Dominant Prey Species at the Altamont Pass Wind Resource Area, California: April 1999-December 2000

    Energy Technology Data Exchange (ETDEWEB)

    Hoover, S.

    2002-06-01

    Studies have shown that raptors flying within the Altamont Pass WRA are vulnerable to fatal turbine collisions, possibly because of their specific foraging and flight behavior. Between June 1999 and June 2000, I conducted 346.5 hours of raptor observations within the Atlamont Pass WRA. Behavior was recorded in relation to characteristics of the topography (slope aspect, elevation, and inclination), the weather, and ground squirrel abundance, as determined by active burrow entrances. The most significant finding of this study revealed that red-tailed hawks and golden eagles flew more in strong winds than in weak winds, particularly along hillsides facing into prevailing winds (as opposed to hillsides shielded from the wind). This is likely a result of the birds' use of declivity currents for lift during flights. These results suggest that certain combinations of topography and weather produce wind currents that are sought out by foraging red-tailed hawks and golden eagles within the Altamont Pass WRA. To decrease raptor mortality, mitigation measures can be targeted to specific areas likely to attract foraging raptors because of their capacity to create particularly favorable wind currents.

  4. Avian risk behavior and fatalities at the Altamont Wind Resource Area: March 1998 - February 1999

    International Nuclear Information System (INIS)

    Since 1981, more than 7,000 wind turbines have been installed in the Altamont Wind Resource Area in north-central California. Currently, about 5,000 turbines are operating. Past research efforts demonstrated that wind turbines frequently kill birds, especially raptors. Little is known about the specific flight and perching behaviors by birds near wind turbines. A better understanding of these interactions may one day yield insights on how to minimize bird fatalities. This Phase 1 progress report summarizes research findings obtained at 20 study plots totaling 785 turbines of various configurations and conducted between March 1998 and February 1999. The authors examined bird use and behaviors and collected data on fatalities at the same turbines throughout the course of the surveys. They completed 745 30-minute point counts (1,702 bird observations) that quantified bird risk behaviors and bird use of the study plots. The four most frequently observed bird species were red-tailed hawks, common ravens, turkey vultures, and golden eagles. During the same period, the authors recorded 95 bird fatalities. Raptors represent 51% (n=49) of the kills found. The data indicate that the relative abundance of species observed does not predict the relative frequency of fatalities per species. Phase II of the research is underway

  5. Session: What can we learn from developed wind resource areas

    Energy Technology Data Exchange (ETDEWEB)

    Thelander, Carl; Erickson, Wally

    2004-09-01

    This session at the Wind Energy and Birds/Bats workshop was composed of two parts intended to examine what existing science tells us about wind turbine impacts at existing wind project sites. Part one dealt with the Altamont Wind Resource area, one of the older wind projects in the US, with a paper presented by Carl Thelander titled ''Bird Fatalities in the Altamont Pass Wind Resource Area: A Case Study, Part 1''. Questions addressed by the presenter included: how is avian habitat affected at Altamont and do birds avoid turbine sites; are birds being attracted to turbine strings; what factors contribute to direct impacts on birds by wind turbines at Altamont; how do use, behavior, avoidance and other factors affect risk to avian species, and particularly impacts those species listed as threatened, endangered, or of conservation concern, and other state listed species. The second part dealt with direct impacts to birds at new generation wind plants outside of California, examining such is sues as mortality, avoidance, direct habitat impacts from terrestrial wind projects, species and numbers killed per turbine rates/MW generated, impacts to listed threatened and endangered species, to USFWS Birds of Conservation Concern, and to state listed species. This session focused on newer wind project sites with a paper titled ''Bird Fatality and Risk at New Generation Wind Projects'' by Wally Erickson. Each paper was followed by a discussion/question and answer period.

  6. Standard metrics and methods for conducting Avian/wind energy interaction studies

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R.L. [California Energy Commission, Sacramento, CA (United States); Davis, H. [National Renewable Energy Lab., Golden, CO (United States); Kendall, W. [National Biological Service, Laurel, MD (United States)] [and others

    1997-12-31

    The awareness of the problem of avian fatalities at large scale wind energy developments first emerged in the late 1980`s at the Altamont Pass Wind Resource Area (WRA) in Central California. Observations of dead raptors at the Altamont Pass WRA triggered concern on the part of regulatory agencies, environmental/conservation groups, resource agencies, and wind and electric utility industries. This led the California Energy Commission staff, along with the planning departments of Alameda, Contra Costa, and Solano counties, to commission a study of bird mortality at the Altamont Pass WRA. In addition to the Altamont Pass WRA, other studies and observations have established that windplants kill birds. Depending upon the specific factors, this may or may not be a serious problem. The current level of scrutiny and caution exhibited during the permitting of a new windplant development in the United States results in costly delays and studies. This is occurring during a highly competitive period for electrical production companies in the USA. Clarification of the bird fatality issue is needed to bring it into perspective. This means standardizing metrics, defining terms, and recommending methods to be used in addressing or studying wind energy/bird interactions.

  7. Quantifying the health and environmental benefits of wind power to natural gas

    International Nuclear Information System (INIS)

    How tangible are the costs of natural gas compared to the benefits of one of the fastest growing sources of electricity – wind energy – in the United States? To answer this question, this article calculates the benefits of wind energy derived from two locations: the 580 MW wind farm at Altamont Pass, CA, and the 22 MW wind farm in Sawtooth, ID. Both wind farms have environmental and economic benefits that should be considered when evaluating the comparative costs of natural gas and wind energy. Though there are uncertainties within the data collected, for the period 2012–2031, the turbines at Altamont Pass will likely avoid anywhere from $560 million to $4.38 billion in human health and climate related externalities, and the turbines at Sawtooth will likely avoid $18 million to $104 million of human health and climate-related externalities. Translating these negative externalities into a cost per kWh of electricity, we estimate that Altamont will avoid costs of 1.8–11.8 cents/kWh and Sawtooth will avoid costs of 1.5–8.2 cents/kWh. - Highlights: ► This study compares the benefits of wind energy with natural gas. ► The Altamont Pass windfarm will avoid $560 million to $4.38 billion in externalities. ► The Sawtooth wind farm will produce about $18 million to $104 million in human health and climate benefits. ► Natural gas prices rise by 1.5–11.8 cents/kWh if they include the cost of such externalities.

  8. Election Districts and Precincts, Altamont, Published in 2001, Duchesne County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Election Districts and Precincts dataset, was produced all or in part from Other information as of 2001. It is described as 'Altamont'. Data by this publisher...

  9. Wind farm array wake losses

    Energy Technology Data Exchange (ETDEWEB)

    Baker, R.W. [Impact Weather, Washougal, WA (United States); McCarthy, E.F. [Wind Economics & Technology, Inc., Martinez, CA (United States)

    1997-12-31

    A wind turbine wake study was conducted in the summer of 1987 at an Altamont Pass wind electric generating facility. The wind speed deficits, turbulence, and power deficits from an array consisting of several rows of wind turbines is discussed. A total of nine different test configurations were evaluated for a downwind spacing ranging from 7 rotor diameters (RD) to 34 RD and a cross wind spacing of 1.3 RD and 2.7 RD. Wake power deficits of 15% were measured at 16 RD and power losses of a few percent were even measurable at 27 RD for the closer cross wind spacing. For several rows of turbines separated by 7-9 RD the wake zones overlapped and formed compound wakes with higher velocity deficits. The wind speed and direction turbulence in the wake was much higher than the ambient turbulence. The results from this study are compared to the findings from other similar field measurements.

  10. 76 FR 69222 - Radio Broadcasting Services; Altamont, OR

    Science.gov (United States)

    2011-11-08

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 Radio Broadcasting Services; Altamont, OR AGENCY: Federal Communications Commission. ACTION: Proposed rule. SUMMARY: This document sets forth a proposal to amend the FM Table of...

  11. Numerical study on the restriction speed of train passing curved rail in cross wind

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The results of numerical investigations of aerodynamic forces and moment coefficients of flow passing a simplified train geometry under different wind speeds are summarized. To compute numerically the different coefficients, the three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations, combined with the k-ε turbulence model, were solved using finite volume technique. The pres-sure-velocity fields were coupled using the SIMPLE algorithm. At each iteration the pressure correction was obtained by solving a velocity divergence-derived Poisson-like equation. With the computed aerodynamic forces, the formula of the restriction speed at which the train passed curved rail in cross wind was deduced to analyse the influences of aerodynamic forces on the restriction speed. Results of numerical investigations showed that aerodynamic lift and overturn moment increased more and more rapidly with train speed and wind speed. The enhancement trends showed nonlinear phenomena and enhanced risk in the course of train movement. When the train travels at a high speed and encounters a huge cross wind, the influence involved by nonlinear risk increment will extremely impair safety of train. The following conclusion can also be drawn: The effect of aerodynamic lift makes restriction speed reduce, however, the influences of aerodynamic drag to the limit train speed rest on the direction of wind flow. When the wind blows from inner rail to outer rail, aerodynamic forces shall reduce the restriction speed, by contraries, when the wind blows from outer rail to inner rail, aerodynamic forces shall increase the restriction speed.

  12. Numerical study on the restriction speed of train passing curved rail in cross wind

    Institute of Scientific and Technical Information of China (English)

    CHEN RuiLin; ZENG QingYuan; ZHONG XinGu; XIANG Jun; GUO XiaoGang; ZHAO Gang

    2009-01-01

    The results of numerical investigations of aerodynamic forces and moment coefficients of flow passing a simplified train geometry under different wind speeds are summarized. To compute numerically the different coefficients, the three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations,combined with the k-ε turbulence model, were solved using finite volume technique. The pressure-velocity fields were coupled using the SIMPLE algorithm. At each iteration the pressure correction was obtained by solving a velocity divergence-derived Poisson-Iike equation. With the computed aerodynamic forces, the formula of the restriction speed at which the train passed curved rail in cross wind was deduced to analyse the influences of aerodynamic forces on the restriction speed. Results of numerical investigations showed that aerodynamic lift and overturn moment increased more and more rapidly with train speed and wind speed. The enhancement trends showed nonlinear phenomena and enhanced risk in the course of train movement. When the train travels at a high speed and encounters a huge cross wind, the influence involved by nonlinear risk increment will extremely impair safety of train.The following conclusion can also he drawn: The effect of aerodynamic lift makes restriction speed reduce, however, the influences of aerodynamic drag to the limit train speed rest on the direction of wind flow. When the wind blows from inner rail to outer rail, aerodynamic forces shall reduce the restriction speed, by contraries, when the wind blows from outer rail to inner rail, aerodynamic forces shall increase the restriction speed.

  13. Potential and site evaluation for a wind energy project on the Gotthard pass

    International Nuclear Information System (INIS)

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of a study that investigated the suitability of a site on the Gotthard pass in Switzerland for the installation of wind turbines. The aims of the study - to provide estimates of wind potential and to clarify various points in connection with building permission - are discussed. The results of the evaluation of measurements made using a 30-metre measuring tower and a portable 10-metre mast are presented. The portable mast was used to estimate wind strengths at different points over the whole area which is being considered for the installation of wind turbines. Possible problems with vertical air-flow and turbulence caused by the specific topography of some parts of the site are discussed. The authors state that around seven megawatt-class wind turbines could be operated with a total installed capacity of around 9 MW. The feeding of the power into the grid and the price of the electricity generated are discussed

  14. Wind Power Curve Modeling Using Statistical Models: An Investigation of Atmospheric Input Variables at a Flat and Complex Terrain Wind Farm

    Energy Technology Data Exchange (ETDEWEB)

    Wharton, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bulaevskaya, V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Irons, Z. [Enel Green Power North America, Andover, MA (United States); Qualley, G. [Infigen Energy, Dallas, TX (United States); Newman, J. F. [Univ. of Oklahoma, Norman, OK (United States); Miller, W. O. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-09-28

    The goal of our FY15 project was to explore the use of statistical models and high-resolution atmospheric input data to develop more accurate prediction models for turbine power generation. We modeled power for two operational wind farms in two regions of the country. The first site is a 235 MW wind farm in Northern Oklahoma with 140 GE 1.68 turbines. Our second site is a 38 MW wind farm in the Altamont Pass Region of Northern California with 38 Mitsubishi 1 MW turbines. The farms are very different in topography, climatology, and turbine technology; however, both occupy high wind resource areas in the U.S. and are representative of typical wind farms found in their respective areas.

  15. Short term hydroelectric power system scheduling with wind turbine generators using the multi-pass iteration particle swarm optimization approach

    International Nuclear Information System (INIS)

    This paper uses multi-pass iteration particle swarm optimization (MIPSO) to solve short term hydroelectric generation scheduling of a power system with wind turbine generators. MIPSO is a new algorithm for solving nonlinear optimal scheduling problems. A new index called iteration best (IB) is incorporated into particle swarm optimization (PSO) to improve solution quality. The concept of multi-pass dynamic programming is applied to modify PSO further and improve computation efficiency. The feasible operational regions of the hydro units and pumped storage plants over the whole scheduling time range must be determined before applying MIPSO to the problem. Wind turbine power generation then shaves the power system load curves. Next, MIPSO calculates hydroelectric generation scheduling. It begins with a coarse time stage and searching space and refines the time interval between two time stages and the search spacing pass by pass (iteration). With the cooperation of agents called particles, the near optimal solution of the scheduling problem can be effectively reached. The effects of wind speed uncertainty were also considered in this paper. The feasibility of the new algorithm is demonstrated by a numerical example, and MIPSO solution quality and computation efficiency are compared to those of other algorithms

  16. Observation Targeting for the Tehachapi Pass and Mid-Columbia Basin: WindSENSE Phase III Project Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Hanley, D

    2011-10-22

    applied and evaluated for the wind plants in the Tehachapi Pass region for a period during the warm season. That research demonstrated that forecast sensitivity derived from the dataset was characterized by well-defined, localized patterns for a number of state variables such as the 80-m wind and the 25-m to 1-km temperature difference prior to the forecast time. The sensitivity patterns produced as part of the Tehachapi Pass study were coherent and consistent with the basic physical processes that drive wind patterns in the Tehachapi area. In Phase II of the WindSENSE project, the ESA-MOOA approach was extended and applied to the wind plants located in the Mid-Columbia Basin wind generation area of Washington-Oregon during the summer and to the Tehachapi Pass region during the winter. The objective of this study was to identify measurement locations and variables that have the greatest positive impact on the accuracy of wind forecasts in the 0- to 6-hour look-ahead periods for the two regions and to establish a higher level of confidence in ESA-MOOA for mesoscale applications. The detailed methodology and results are provided in separate technical reports listed in the publications section below. Ideally, the data assimilation scheme used in the Phase III experiments would have been based upon an ensemble Kalman filter (EnKF) that was similar to the ESA method used to diagnose the Mid-Columbia Basin sensitivity patterns in the previous studies. However, running an EnKF system at high resolution is impractical because of the very high computational cost. Thus, it was decided to use a three-dimensional variational (3DVAR) analysis scheme that is less computationally intensive. The objective of this task is to develop an observation system deployment strategy for the mid Columbia Basin (i.e. the BPA wind generation region) that is designed to produce the maximum benefit for 1- to 6-hour ahead forecasts of hub-height ({approx}80 m) wind speed with a focus on periods of large

  17. Wind Power Curve Modeling in Simple and Complex Terrain

    Energy Technology Data Exchange (ETDEWEB)

    Bulaevskaya, V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wharton, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Irons, Z. [Enel Green Power North America, Andover, MA (United States); Qualley, G. [Pentalum, Colleyville, TX (United States)

    2015-02-09

    Our previous work on wind power curve modeling using statistical models focused on a location with a moderately complex terrain in the Altamont Pass region in northern California (CA). The work described here is the follow-up to that work, but at a location with a simple terrain in northern Oklahoma (OK). The goal of the present analysis was to determine the gain in predictive ability afforded by adding information beyond the hub-height wind speed, such as wind speeds at other heights, as well as other atmospheric variables, to the power prediction model at this new location and compare the results to those obtained at the CA site in the previous study. While we reach some of the same conclusions at both sites, many results reported for the CA site do not hold at the OK site. In particular, using the entire vertical profile of wind speeds improves the accuracy of wind power prediction relative to using the hub-height wind speed alone at both sites. However, in contrast to the CA site, the rotor equivalent wind speed (REWS) performs almost as well as the entire profile at the OK site. Another difference is that at the CA site, adding wind veer as a predictor significantly improved the power prediction accuracy. The same was true for that site when air density was added to the model separately instead of using the standard air density adjustment. At the OK site, these additional variables result in no significant benefit for the prediction accuracy.

  18. Opportunities and challenges in assessing climate change impacts on wind energy-a critical comparison of wind speed projections in California

    International Nuclear Information System (INIS)

    Future climate change is expected to alter the spatial and temporal distribution of surface wind speeds (SWS), with associated impacts on electricity generation from wind energy. However, the predictions for the direction and magnitude of these changes hinge critically on the assessment methods used. Many climate change impact analyses, including those focused on wind energy, use individual climate models and/or statistical downscaling methods rooted in historical observations. Such studies may individually suggest an unrealistically high level of scientific certainty due to the absence of competing projections (over the same region, time period, etc). A new public data archive, the North American Regional Climate Change Assessment Program (NARCCAP), allows for a more comprehensive perspective on regional climate change impacts, here applied to three wind farm sites in California. We employ NARCCAP regional climate model data to estimate changes in SWS expected to occur in the mid-21st century at three wind farm regions: Altamont Pass, San Gorgonio Pass, and Tehachapi Pass. We examined trends in SWS magnitude and frequency using three different global/regional model pairs, focused on model evaluation, seasonal cycle, and long-term trends. Our results, while specific to California, highlight the opportunities and limitations in NARCCAP and other publicly available meteorological data sets for energy analysis, and the importance of using multiple models for climate change impact assessment. Although spatial patterns in current wind conditions agree fairly well among models and with NARR (North American Regional Reanalysis) data, results vary widely at our three sites of interest. This poor performance and model disagreement may be explained by complex topography, limited model resolution, and differences in model physics. Spatial trends and site-specific estimates of annual average changes (1980-2000 versus 2051-71) also differed widely across models. All models

  19. Map-Based Repowering and Reorganization of a Wind Resource Area to Minimize Burrowing Owl and Other Bird Fatalities

    Directory of Open Access Journals (Sweden)

    Lee Neher

    2009-10-01

    Full Text Available Wind turbines in the Altamont Pass Wind Resource Area (Alameda/Contra Costa Counties, California, USA generate about 730 GWh of electricity annually, but have been killing thousands of birds each year, including >2,000 raptors and hundreds of burrowing owls. We have developed collision hazard maps and hazard ratings of wind turbines to guide relocation of existing wind turbines and careful repowering to modern turbines to reduce burrowing owl fatalities principally, and other birds secondarily. Burrowing owls selected burrow sites lower on slopes and on smaller, shallower slopes than represented by the average 10 × 10 m2 grid cell among 187,908 grid cells sampled from 2,281,169 grid cells comprising a digital elevation model (DEM of the study area. Fuzzy logic and discriminant function analysis produced likelihood surfaces encompassing most burrowing owl burrows within a fraction of the study area, and the former corresponded with burrowing owl fatalities and the latter with other raptor fatalities. Our ratings of wind turbine hazard were more predictive of burrowing owl fatalities, but would be more difficult to implement. Careful repowering to modern wind turbines would most reduce fatalities of burrowing owls and other birds while adding about 1,000 GWh annually toward California’s 33% Renewable Portfolio Standard.

  20. Low frequency sound from wind turbine arrays

    International Nuclear Information System (INIS)

    Due to the effects of tower wakes and atmospheric turbulence, wind turbines emit sounds at low frequencies characterized by the turbine blade passage frequency and its harmonics. These frequencies range from the sub-audible tones of a few hertz up to frequencies in the lower audible range of 50 to 100 Hz. The results of tests on a small controlled array of turbines at the U.S. Windpower Windplant in Altamont Pass, California, indicate that the low frequency sound propagates according to the well established physical principle of spherical spreading. The effect of operating multiple turbines can be accurately modeled by considering each turbine to be a randomly phased acoustic point source. In order to characterize the low frequency sound, the AWEA Standard, Low-Frequency, C-Weighted metric is recommended for both rms and impulse-hold transient signal processing. To assess the effects of this low frequency sound on community receptors an appropriate criterion based on previous results and a corresponding simplified methodology are developed. (Author)

  1. Wind energy development in California, USA

    Science.gov (United States)

    Wilshire, H.; Prose, D.

    1987-01-01

    Windfarms have been developed rapidly in California in the last few years. The impetus has been a legislated goal to generate 10% of California's electricity by windpower by the year 2000, and generous state and federal tax incentives. Windpower is promoted as environmentally benign, which it is in traditional uses. The California program, however, is not traditional: it calls for centralized development of a magnitude sufficient to offset significant amounts of fossil fuels now used to generate electricity. Centralized windfarm development, as exemplified by the Altamont Pass, Tehachapi Mountains, and San Gorgonio Pass developments, involves major road building projects in erosion-sensitive terrain, effective closure of public lands, and other detrimental effects. A windfarm consisting of 200 turbines with 17-m rotors located in steep terrain 16 km from an existing corridor might occupy 235 ha and physically disturb 86 ha. With average annual wind speeds of 22.5 km/h, the farm would generate about 10??106 kWh/year at present levels of capacity. This annual production would offset 1% of one day's consumption of oil in California. To supply 10% of the state's electricity (at 1984 production rates) would require about 600,000 turbines of the type in common use today and would occupy more than 685,000 ha. It is likely that indirect effects would be felt in much larger areas and would include increased air and water pollution resulting from accelerated erosion, degradation of habitat of domestic and wild animals, damage to archaeological sites, and reduction of scenic quality of now-remote areas of the state. ?? 1987 Springer-Verlag New York Inc.

  2. Passing excellence

    Science.gov (United States)

    Tsoupikova, Daria

    2007-02-01

    This paper describes the research and development of a virtual reality visualization project "Passing excellence" about the world famous architectural ensemble "Kizhi". The Kizhi Pogost is located on an island in Lake Onega in northern Karelia in Russia. It is an authentic museum of an ancient wood building tradition which presents a unique artistic achievement. This ensemble preserves a concentration of masterpieces of the Russian heritage and is included in the List of Most Endangered Sites of the World Monuments Watch protected by World Heritage List of UNESCO. The project strives to create a unique virtual observation of the dynamics of the architectural changes of the museum area beginning from the 15th Century up to the 21st Century. The visualization is being created to restore the original architecture of Kizhi island based on the detailed photographs, architectural and geometric measurements, textural data, video surveys and resources from the Kizhi State Open-Air Museum archives. The project is being developed using Electro, an application development environment for the tiled display high-resolution graphics visualization system and can be shown on the virtual reality systems such as the GeoWall TM and the C-Wall.

  3. Passing and Catching in Rugby.

    Science.gov (United States)

    Namudu, Mike M.

    This booklet contains the fundamentals for rugby at the primary school level. It deals primarily with passing and catching the ball. It contains instructions on (1) holding the ball for passing, (2) passing the ball to the left--standing, (3) passing the ball to the left--running, (4) making a switch pass, (5) the scrum half's normal pass, (6) the…

  4. The Band Pass Filter

    OpenAIRE

    Christiano, Lawrence J.; Terry J. Fitzgerald

    1999-01-01

    The `ideal' band pass filter can be used to isolate the component of a time series that lies within a particular band of frequencies. However, applying this filter requires a dataset of infinite length. In practice, some sort of approximation is needed. Using projections, we derive approximations that are optimal when the time series representations underlying the raw data have a unit root, or are stationary about a trend. We identify one approximation which, though it is only optimal for one...

  5. Multiple-pass reflectometer

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, D.F. (Los Alamos National Lab., NM); Baumeister, P.

    1981-11-15

    The multiple-pass reflectometer has been shown to be a convenient and precise instrument for measuring absolute spectral reflectance values in excess of 0.99. Given here is an extension of earlier work. We present details of the setup, operation, parameter optimization, and some limitations of the reflectometer. For a carefully aligned instrument the precision of the measurement is limited by the uncertainty in the computer fit of a straight line to the data. For the uv and visible spectral regions, typical reflectance precision is a few parts in 10/sup 4/. Systematic errors due to nonuniform photosurfaces and astigmatism have been minimized for the setup described here.

  6. TRT Barrel milestones passed

    CERN Multimedia

    Ogren, H

    2004-01-01

    The barrel TRT detector passed three significant milestones this spring. The Barrel Support Structure (BSS) was completed and moved to the SR-1 building on February 24th. On March 12th the first module passed the quality assurance testing in Building 154 and was transported to the assembly site in the SR-1 building for barrel assembly. Then on April 21st the final production module that had been scanned at Hampton University was shipped to CERN. TRT Barrel Module Production The production of the full complement of barrel modules (96 plus 9 total spares) is now complete. This has been a five-year effort by Duke University, Hampton University, and Indiana University. Actual construction of the modules in the United States was completed in the first part of 2004. The production crews at each of the sites in the United States have now completed their missions. They are shown in the following pictures. Duke University: Production crew with the final completed module. Indiana University: Module producti...

  7. Passing the baton

    CERN Multimedia

    2011-01-01

    It was not only in South Korea that batons were being passed last week. While the cream of the world’s athletes were competing in the World Athletics Championships, the cream of the world’s accelerator scientists were on their way to San Sebastian in Spain for the International Particle Accelerator Conference.  One of them was carrying a rather special baton for a handover of a different kind.   When Fermilab’s Vladimir Shiltsev handed the high-energy frontier baton to CERN’s Mike Lamont on Tuesday, it marked the end of an era: a time to look back on the phenomenal contribution the Tevatron has made to particle physics over its 25-year operational lifetime, and the great contribution Fermilab has made over that period to global collaboration in particle physics. There’s always a lot of emotion involved in passing the baton. In athletics, it’s the triumph of wining or the heartbreak of losing. But for this special baton, the...

  8. WebPASS Explorer (HR Personnel Management)

    Data.gov (United States)

    US Agency for International Development — WebPass Explorer (WebPASS Framework): USAID is partnering with DoS in the implementation of their WebPass Post Personnel (PS) Module. WebPassPS does not replace...

  9. WebPASS PP (HR Personnel Management)

    Data.gov (United States)

    US Agency for International Development — WebPass Explorer (WebPASS Framework): USAID is partnering with DoS in the implementation of their WebPass Post Personnel (PS) Module. WebPassPS does not replace...

  10. Advanced Performance Hydraulic Wind Energy

    Science.gov (United States)

    Jones, Jack A.; Bruce, Allan; Lam, Adrienne S.

    2013-01-01

    The Jet Propulsion Laboratory, California Institute of Technology, has developed a novel advanced hydraulic wind energy design, which has up to 23% performance improvement over conventional wind turbine and conventional hydraulic wind energy systems with 5 m/sec winds. It also has significant cost advantages with levelized costs equal to coal (after carbon tax rebate). The design is equally applicable to tidal energy systems and has passed preliminary laboratory proof-of-performance tests, as funded by the Department of Energy.

  11. Multi-pass spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Spectroscopic ellipsometry is an established technique, particularly useful for thickness measurements of thin films. It measures polarization rotation after a single reflection of a beam of light on the measured substrate at a given incidence angle. In this paper, we report the development of multi-pass spectroscopic ellipsometry where the light beam reflects multiple times on the sample. We have investigated both theoretically and experimentally the effect of sample reflectivity, number of reflections (passes), angles of incidence and detector dynamic range on ellipsometric observables tanΨ and cosΔ. The multiple pass approach provides increased sensitivity to small changes in Ψ and Δ, opening the way for single measurement determination of optical thickness T, refractive index n and absorption coefficient k of thin films, a significant improvement over the existing techniques. Based on our results, we discuss the strengths, the weaknesses and possible applications of this technique. - Highlights: • We present multi-pass spectroscopic ellipsometry (MPSE), a multi-pass approach to ellipsometry. • Different detectors, samples, angles of incidence and number of passes were tested. • N passes improve polarization ratio sensitivity to the power of N. • N reflections improve phase shift sensitivity by a factor of N. • MPSE can significantly improve thickness measurements in thin films

  12. Synthesis and Comparison of Baseline Avian and Bat Use, Raptor Nesting and Mortality Information from Proposed and Existing Wind Developments: Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Erickson, Wallace P.

    2002-12-01

    Primarily due to concerns generated from observed raptor mortality at the Altamont Pass (CA) wind plant, one of the first commercial electricity generating wind plants in the U.S., new proposed wind projects both within and outside of California have received a great deal of scrutiny and environmental review. A large amount of baseline and operational monitoring data have been collected at proposed and existing U.S. wind plants. The primary use of the avian baseline data collected at wind developments has been to estimate the overall project impacts (e.g., very low, low, moderate, and high relative mortality) on birds, especially raptors and sensitive species (e.g., state and federally listed species). In a few cases, these data have also been used for guiding placement of turbines within a project boundary. This new information has strengthened our ability to accurately predict and mitigate impacts from new projects. This report should assist various stakeholders in the interpretation and use of this large information source in evaluating new projects. This report also suggests that the level of baseline data (e.g., avian use data) required to adequately assess expected impacts of some projects may be reduced. This report provides an evaluation of the ability to predict direct impacts on avian resources (primarily raptors and waterfowl/waterbirds) using less than an entire year of baseline avian use data (one season, two seasons, etc.). This evaluation is important because pre-construction wildlife surveys can be one of the most time-consuming aspects of permitting wind power projects. For baseline data, this study focuses primarily on standardized avian use data usually collected using point count survey methodology and raptor nest survey data. In addition to avian use and raptor nest survey data, other baseline data is usually collected at a proposed project to further quantify potential impacts. These surveys often include vegetation mapping and state or

  13. The Name-Passing Calculus

    OpenAIRE

    Fu, Yuxi; Zhu, Han

    2015-01-01

    Name-passing calculi are foundational models for mobile computing. Research into these models has produced a wealth of results ranging from relative expressiveness to programming pragmatics. The diversity of these results call for clarification and reorganization. This paper applies a model independent approach to the study of the name-passing calculi, leading to a uniform treatment and simplification. The technical tools and the results presented in the paper form the foundation for a theory...

  14. Session: Avoiding, minimizing, and mitigating avian and bat impacts

    International Nuclear Information System (INIS)

    This session at the Wind Energy and Birds/Bats workshop consisted of two presentations followed by a discussion/question answer period. The session addressed a variety of questions related to avoiding, minimizing, and mitigating the avian and bat impacts of wind power development including: what has been learned from operating turbines and mitigating impacts where they are unavoidable, such as at Altamont Pass WRA, and should there be mitigation measures such as habitat creation or land conservation where impacts occur. Other impact minimization and mitigation approaches discussed included: location and siting evaluations; options for construction and operation of wind facilities; turbine lighting; and the physical alignment/orientation. Titles and authors of the presentations were: 'Bird Fatalities in the Altamont Pass Wind Resource Area: A Case Study, Part II' by Carl Thelander and 'Prevention and Mitigation of Avian Impacts at Wind Power Facilities' by Paul Kerlinger

  15. Low pass filter compensation integrator based sensorless control of direct-drive permanent magnet wind generators%基于低通滤波补偿积分器的直驱型永磁风力发电机无位置传感器控制

    Institute of Scientific and Technical Information of China (English)

    唐芬; 金新民; 周啸; 童亦斌

    2011-01-01

    With the characteristics of direct-drive permanent magnet synchronous generators (PMSG),a sensorless zero d-axis current control(ZDAC) method based on low pass filter compensation integrator (LPFCI) is proposed. Its implementation principle is introduced in detail. Furthermore, LPFCI is discussed in depth. Finally, simulation and experiment results on a low power permanent magnet wind generation platform indicate the feasibility of the method. Results also show its excellent steady and torque dynamic response performance as well as easy implementation.%针对永磁直驱风力发电机的特点,本文采用一种基于低通滤波补偿积分器的无位置传感器零d轴电流控制技术.在论述该控制技术实现原理的基础上,深入分析了低通滤波补偿积分器特点,最后通过仿真和小功率直驱型永磁风力发电实验平台,验证了其有效性.结果表明,该方法具有较好的稳态与转矩动态响应性能,且工程实现较为简单.

  16. Outsourcing and Pass-Through

    OpenAIRE

    Hellerstein, Rebecca; Villas-Boas, Sofia B.

    2010-01-01

    A large share of international trade occurs through intra-firm transactions. We show that this common cross-border organization of the firm has implications for the well-documented incomplete transmission of shocks across such borders. We present new evidence of an inverse relationship between a firm’s outsourcing of inputs and its rate of exchange-rate pass-through. We then develop a structural econometric model with final assemblers and upstream parts suppliers to quantify how firms’ organi...

  17. MDMP: Managed Data Message Passing

    OpenAIRE

    Jackson, Adrian; Strand, Par

    2013-01-01

    MDMP is a new parallel programming approach that aims to provide users with an easy way to add parallelism to programs, optimise the message passing costs of traditional scientific simulation algorithms, and enable existing MPI-based parallel programs to be optimised and extended without requiring the whole code to be re-written from scratch. MDMP utilises a directives based approach to enable users to specify what communications should take place in the code, and then implements those commun...

  18. Outsourcing and pass-through

    OpenAIRE

    Hellerstein, Rebecca; Villas-Boas, Sofia B.

    2006-01-01

    A large share of international trade occurs through intra-firm transactions. We show that this common cross-border organization of the firm has implications for the well-documented incomplete transmission of shocks across such borders. We present new evidence of an inverse relationship between a firm’s outsourcing of inputs and its rate of exchange-rate pass-through. We then develop a structural econometric model with final assemblers and upstream parts suppliers to quantify how firms’ or...

  19. A single pass electron accelerator

    International Nuclear Information System (INIS)

    Higher volumes, increasing competition and the need to improve quality have led us to re-examine the process for irradiation of tubing and wire. Traditionally in Raychem, product irradiation has involved the use of large multi-purpose facilities that were designed to handle relatively small volumes of a large variety of products as a separate process. Today, with larger volumes of certain products, there is an interest in combining processes to improve quality and reduce cost. We have recently designed and constructed a small, low voltage accelerator system that can be placed in-line with another manufacturing process and can uniformly irradiate a tube or wire product in a single pass. The system is comprised to two conventional accelerator systems having elongated filaments and placed on opposite sides of a linear product path. The ribbon shaped electron beams from these two accelerators are scanned, after acceleration toward the product path, in a conventional manner and 180 degrees out of phase from each other. The two accelerated electron beams then enter a third magnetic field that is synchronous with the scanning magnets and whose oscillating polarity is such that the ribbon beams are converged onto a tubular shaped window close to and around a segment of the product path. Trials with a prototype system have produced tubing having a dose concentricity of better than ± 10 percent on a single pass through the system. (author)

  20. A single pass electron accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Schuetz, M.N.; Vroom, D.A. [Raychem Corp., Menlo Park, CA (United States)

    1995-10-01

    Higher volumes, increasing competition and the need to improve quality have led us to re-examine the process for irradiation of tubing and wire. Traditionally in Raychem, product irradiation has involved the use of large multi-purpose facilities that were designed to handle relatively small volumes of a large variety of products as a separate process. Today, with larger volumes of certain products, there is an interest in combining processes to improve quality and reduce cost. We have recently designed and constructed a small, low voltage accelerator system that can be placed in-line with another manufacturing process and can uniformly irradiate a tube or wire product in a single pass. The system is comprised to two conventional accelerator systems having elongated filaments and placed on opposite sides of a linear product path. The ribbon shaped electron beams from these two accelerators are scanned, after acceleration toward the product path, in a conventional manner and 180 degrees out of phase from each other. The two accelerated electron beams then enter a third magnetic field that is synchronous with the scanning magnets and whose oscillating polarity is such that the ribbon beams are converged onto a tubular shaped window close to and around a segment of the product path. Trials with a prototype system have produced tubing having a dose concentricity of better than {+-} 10 percent on a single pass through the system. (author).

  1. A single pass electron accelerator

    Science.gov (United States)

    Schuetz, Marlin N.; Vroom, David A.

    1995-02-01

    Higher volumes, increasing competition and the need to improve quality have led us to re-examine the process for irradiation of tubing and wire. Traditionallyin Raychem, product irradiation has involved the use of large multi-purpose facilities that were designed to handle relatively small volumes of a large variety of products as a separate process. Today, with larger volumes of certain products, there is an interest in combining processes to improve quality and reduce cost. We have recently designed and constructed a small, low voltage accelerator system that can be placed in-line with another manufacturing process and can uniformly irradiate a tube or wire product in a single pass. The system is comprised of two conventional accelerator systems having elongated filaments and placed on opposite sides of a linear product path. The ribbon shaped electron beams from these two accelerators are scanned, after acceleration toward the product path, in a conventional manner and 180 degrees out of phase from each other. The two accelerated electron beams then enter a third magnetic field that is synchronous with the scanning magnets and whose oscillating polarity is such that the ribbon beams are converged onto a tubular shaped window close to and around a segment of the product path. Trials with a prototype system have produced tubing having a dose concentricity of better than ± 10 percent on a single pass through the system.

  2. Solar wind travel time

    Science.gov (United States)

    Russell, C. T.

    A useful rule of thumb in solar terrestrial studies is that the solar wind travels 4 Earth radii (RE) per minute. Long-term studies of solar wind velocity [e.g., Luhmann et al., 1993; 1994] show that the median velocity is about 420 km/s, corresponding to 3.96 RE min-1. The quartiles are about 370 km/s and 495 km/s, corresponding to 3.48 Re min-1 and 4.66 Re min-1 respectively. This number helps estimate the delays expected when observing a discontinuity at a solar wind monitor; one example is ISEE-3 when it was at the forward libration point (about 60 min). It is also helpful for estimating how much time passes before the dayside magnetosphere is compressed as denser solar wind flows by (about 2.5 min).

  3. Senate passes clean air bill

    Science.gov (United States)

    In an 89 to 11 vote the Senate passed a clean air bill aimed at reducing pollution by the turn of the century by imposing tougher controls on American industry. The bill is the first revision of the Clean Air Act of 1970 in 13 years and calls for new limits on auto pollution to clean up smog in most U.S. cities, decreasing by half emissions by power plants that cause acid rain to protect the ecology, and increasing technological controls on factories to protect against cancer-causing and toxic substances. The bill will add about $20 billion per year to the estimated $33 billion cost of complying with current pollution laws.

  4. The PASS project architectural model

    International Nuclear Information System (INIS)

    The PASS project has as its goal the implementation of solutions to the foreseen data access problems of the next generation of scientific experiments. The architectural model results from an evaluation of the operational and technical requirements and is described in terms of an abstract reference model, an implementation model and a discussion of some design aspects. The abstract reference model describes a system that matches the requirements in terms of its components and the mechanisms by which they communicate, but does not discuss policy or design issues that would be necessary to match the model to an actual implementation. Some of these issues are discussed, but more detailed design and simulation work will be necessary before choices can be made

  5. WebPASS ICASS (HR Personnel Management)

    Data.gov (United States)

    US Agency for International Development — WebPASS Joint Administrative Support Platforms Post Administrative Software Suite - U.S. Department of State Executive Officers application suite. Web.PASS is the...

  6. Triplets pass their pressure test

    CERN Multimedia

    2007-01-01

    All the LHC inner triplets have now been repaired and are in position. The first ones have passed their pressure tests with flying colours. The repaired inner triplet at LHC Point 1, right side (1R). Ranko Ostojic (on the right), who headed the team responsible for repairing the triplets, shows the magnet to Robert Zimmer, President of the University of Chicago and of Fermi Research Alliance, who visited CERN on 20th August.Three cheers for the triplets! All the LHC inner triplets have now been repaired and are in position in the tunnel. Thanks to the mobilisation of a multidisciplinary team from CERN and Fermilab, assisted by the KEK Laboratory and the Lawrence Berkeley National Laboratory (LBNL), a solution has been found, tested, validated and applied. At the end of March this year, one of the inner triplets at Point 5 failed to withstand a pressure test. A fault was identified in the supports of two out of the three quadruple magne...

  7. Wind Power

    OpenAIRE

    Makhalas, Kharsan Al; Alsehlli, Faisal

    2015-01-01

    This Bachelor thesis has been written at the Blekinge Institute of Technology. This thesis concentrates on the wind power and their components, also the large wind farm is studied. The electrical power is generated by using the power in wind to drive a wind turbine to produce mechanical power. This mechanical power can be converted into electrical power by using electrical induction generators. There are two types of the wind turbines, the horizontal axis and vertical axis wind turbine, where...

  8. Background sound levels and wind turbine noise

    International Nuclear Information System (INIS)

    This paper reviewed the regulators' approach to the challenge of establishing sound level limits in wind turbine arrays that allow for variations in background sound level with wind speed. Wind speed influences the amount of noise produced by wind turbines and also the noise associated with wind passing over terrain and through foliage. New guidelines by Ontario's Ministry of the Environment were discussed along with wind noise as a function of speed in remote locations having a variety of terrain and foliage types. It was concluded that wind induced noise can effectively mask the steady noise of wind turbine generators, especially during high wind conditions. The extent of wind induced noise depends on the local terrain, foliage and wind speed through vegetation. Masking wind turbine noise by wind induced noise in vegetation can be reduced during stable atmospheric conditions which are common at night. The extent of masking by wind induced noise depends on the level and characteristics of wind turbine noise and wind induced noise. 9 refs., 2 tabs., 2 figs

  9. Economics of Residential Photovoltaic and Wind Systems in Arizona and California

    Science.gov (United States)

    An, Wen

    Renewable energy has been a very hot topic in recent years due to the traditional energy crisis. Incentives that encourage the renewables have been established all over the world. Ordinary homeowners are also seeking ways to exploit renewable energy. In this thesis, residential PV system, wind turbine system and a hybrid wind/solar system are all investigated. The solar energy received by the PV panels varies with many factors. The most essential one is the irradiance. As the PV panel been installed towards different orientations, the incident insolation received by the panel also will be different. The differing insolation corresponds to the different angles between the irradiance and the panel throughout the day. The result shows that for PV panels in the northern hemisphere, the ones facing south obtain the highest level insolation and thus generate the most electricity. However, with the two different electricity rate plans, flat rate plan and TOU (time of use) plan, the value of electricity that PV generates is different. For wind energy, the wind speed is the most significant variable to determine the generation of a wind turbine. Unlike solar energy, wind energy is much more regionally dependent. Wind resources vary between very close locations. As expected, the result shows that, larger wind speed leads to more electricity generation and thus shorter payback period. For the PV/wind hybrid system, two real cases are analyzed for Altamont and Midhill, CA. In this part, the impact of incentives, system cost and system size are considered. With a hybrid system, homeowners may choose different size combinations between PV and wind turbines. It turns out that for these two locations, the system with larger PV output always achieve a shorter payback period due to the lower cost. Even though, for a longer term, the system with a larger wind turbine in locations with excellent wind resources may lead to higher return on investment. Meanwhile, impacts of both wind

  10. The prevention of wind erosion in agriculture

    NARCIS (Netherlands)

    Zaslavsky, D.

    1977-01-01

    The wind erosion is a problem over more than 80 000 hectares in the Netherlands. The damage in wind erodible areas is on the average at least 150 Dfl. per hectare per year. A lot of damages very probably pass unobserved or unreported.

  11. Photoacoustic Soot Spectrometer (PASS) Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, M [Los Alamos National Laboratory; Springston, S [Brookhaven National Laboratory; Koontz, A [Pacific Northwest National Laboratory; Aiken, A [Los Alamos National Laboratory

    2013-01-17

    The photoacoustic soot spectrometer (PASS) measures light absorption by aerosol particles. As the particles pass through a laser beam, the absorbed energy heats the particles and in turn the surrounding air, which sets off a pressure wave that can be detected by a microphone. The PASS instruments deployed by ARM can also simultaneously measure the scattered laser light at three wavelengths and therefore provide a direct measure of the single-scattering albedo. The Operator Manual for the PASS-3100 is included here with the permission of Droplet Measurement Technologies, the instrument’s manufacturer.

  12. Cost pass-through under delegation

    OpenAIRE

    2008-01-01

    The rate of cost pass-through exceeds 50% under strategic delegation of decision-making to managers with sales revenue contracts - regardless of the number of firms in the industry and demand curvature. This contrasts sharply with profit-maximization, for which cost pass-through can take on any positive value. The key intuition is that firms under delegation act as if they faced more rivals than they actually do, thus pushing cost pass-through towards 100%. Cost pass-through with market share...

  13. Pass-transistor very large scale integration

    Science.gov (United States)

    Maki, Gary K. (Inventor); Bhatia, Prakash R. (Inventor)

    2004-01-01

    Logic elements are provided that permit reductions in layout size and avoidance of hazards. Such logic elements may be included in libraries of logic cells. A logical function to be implemented by the logic element is decomposed about logical variables to identify factors corresponding to combinations of the logical variables and their complements. A pass transistor network is provided for implementing the pass network function in accordance with this decomposition. The pass transistor network includes ordered arrangements of pass transistors that correspond to the combinations of variables and complements resulting from the logical decomposition. The logic elements may act as selection circuits and be integrated with memory and buffer elements.

  14. Low-Noise Band-Pass Amplifier

    Science.gov (United States)

    Kleinberg, L.

    1982-01-01

    Circuit uses standard components to overcome common limitation of JFET amplifiers. Low-noise band-pass amplifier employs JFET and operational amplifier. High gain and band-pass characteristics are achieved with suitable choice of resistances and capacitances. Circuit should find use as low-noise amplifier, for example as first stage instrumentation systems.

  15. Basic DTU Wind Energy controller

    DEFF Research Database (Denmark)

    Hansen, Morten Hartvig; Henriksen, Lars Christian

    This report contains a description and documentation, including source code, of the basic DTU Wind Energy controller applicable for pitch-regulated, variable speed wind turbines. The controller features both partial and full load operation capabilities as well as switching mechanisms ensuring...... in the feedback. The controller relies on generator speed as the primary feedback sensor. Additionally, the reference generator power is used as a feedback term to smoothen the switching between partial and full load operation. Optionally, a low-pass filtered wind speed measurement can be used for...... wind speed dependent minimum blade pitch in partial load operation. The controller uses the collective blade pitch angle and electromagnetic generator torque to control the wind turbine. In full load operation a feedback term from the collective blade pitch angle is used to schedule the gains of the...

  16. Humans Can Pass Staph Germs to Monkeys

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_160157.html Humans Can Pass Staph Germs to Monkeys Scientists found ... green monkeys in The Gambia were acquired from humans. Most of the human-to-monkey transmission likely ...

  17. How to pass higher English colour

    CERN Document Server

    Bridges, Ann

    2009-01-01

    How to Pass is the Number 1 revision series for Scottish qualifications across the three examination levels of Standard Grade, Intermediate and Higher! Second editions of the books present all of the material in full colour for the first time.

  18. Automated Procedure for Roll Pass Design

    Science.gov (United States)

    Lambiase, F.; Langella, A.

    2009-04-01

    The aim of this work has been to develop an automatic roll pass design method, capable of minimizing the number of roll passes. The adoption of artificial intelligence technologies, particularly expert systems, and a hybrid model for the surface profile evaluation of rolled bars, has allowed us to model the search for the minimal sequence with a tree path search. This approach permitted a geometrical optimization of roll passes while allowing automation of the roll pass design process. Moreover, the heuristic nature of the inferential engine contributes a great deal toward reducing search time, thus allowing such a system to be employed for industrial purposes. Finally, this new approach was compared with other recently developed automatic systems to validate and measure possible improvements among them.

  19. Message Passing Framework for Globally Interconnected Clusters

    Science.gov (United States)

    Hafeez, M.; Asghar, S.; Malik, U. A.; Rehman, A.; Riaz, N.

    2011-12-01

    In prevailing technology trends it is apparent that the network requirements and technologies will advance in future. Therefore the need of High Performance Computing (HPC) based implementation for interconnecting clusters is comprehensible for scalability of clusters. Grid computing provides global infrastructure of interconnecting clusters consisting of dispersed computing resources over Internet. On the other hand the leading model for HPC programming is Message Passing Interface (MPI). As compared to Grid computing, MPI is better suited for solving most of the complex computational problems. MPI itself is restricted to a single cluster. It does not support message passing over the internet to use the computing resources of different clusters in an optimal way. We propose a model that provides message passing capabilities between parallel applications over the internet. The proposed model is based on Architecture for Java Universal Message Passing (A-JUMP) framework and Enterprise Service Bus (ESB) named as High Performance Computing Bus. The HPC Bus is built using ActiveMQ. HPC Bus is responsible for communication and message passing in an asynchronous manner. Asynchronous mode of communication offers an assurance for message delivery as well as a fault tolerance mechanism for message passing. The idea presented in this paper effectively utilizes wide-area intercluster networks. It also provides scheduling, dynamic resource discovery and allocation, and sub-clustering of resources for different jobs. Performance analysis and comparison study of the proposed framework with P2P-MPI are also presented in this paper.

  20. Message Passing Framework for Globally Interconnected Clusters

    International Nuclear Information System (INIS)

    In prevailing technology trends it is apparent that the network requirements and technologies will advance in future. Therefore the need of High Performance Computing (HPC) based implementation for interconnecting clusters is comprehensible for scalability of clusters. Grid computing provides global infrastructure of interconnecting clusters consisting of dispersed computing resources over Internet. On the other hand the leading model for HPC programming is Message Passing Interface (MPI). As compared to Grid computing, MPI is better suited for solving most of the complex computational problems. MPI itself is restricted to a single cluster. It does not support message passing over the internet to use the computing resources of different clusters in an optimal way. We propose a model that provides message passing capabilities between parallel applications over the internet. The proposed model is based on Architecture for Java Universal Message Passing (A-JUMP) framework and Enterprise Service Bus (ESB) named as High Performance Computing Bus. The HPC Bus is built using ActiveMQ. HPC Bus is responsible for communication and message passing in an asynchronous manner. Asynchronous mode of communication offers an assurance for message delivery as well as a fault tolerance mechanism for message passing. The idea presented in this paper effectively utilizes wide-area intercluster networks. It also provides scheduling, dynamic resource discovery and allocation, and sub-clustering of resources for different jobs. Performance analysis and comparison study of the proposed framework with P2P-MPI are also presented in this paper.

  1. Wind energy

    International Nuclear Information System (INIS)

    Wind is not only free, it is inexhaustible. Wind energy has come a very long way since the prototypes of just 20 years ago. Today's wind turbines are state-of-the-art technology - modular and quick to install anywhere where there is sufficient wind potential to provide secure, centralised or distributed generation. It is a global phenomenon, the world's fastest growing energy sector, a clean and effective modern technology that completely avoids pollution and thus reducing the 'green house' effect. (Original)

  2. The market for wind power plants in Germany

    International Nuclear Information System (INIS)

    The report focuses on development and production on the market for wind power plants in Germany. It is expected that the German market for wind power plants will grow strongly in the coming years, due to the present small utilisation of the wind power potential combined with the passing of the new German electricity act. The marketing possibilities will be very interesting for the Danish exporters - provided that the Danish wind power industry is dynamic enough to meet the demands

  3. Wind turbine

    International Nuclear Information System (INIS)

    The title invention concerns a wind turbine with a rotor, consisting of a number of blades, each with a front edge and an irregular shaped (sawtooth) back edge. This wind turbine aims at reducing the noise pollution of wind turbines. 1 fig

  4. A cryogenic circulating advective multi-pass absorption cell

    International Nuclear Information System (INIS)

    A novel absorption cell has been developed to enable a spectroscopic survey of a broad range of polycyclic aromatic hydrocarbons (PAH) under astrophysically relevant conditions and utilizing a synchrotron radiation continuum to test the still controversial hypothesis that these molecules or their ions could be carriers of the diffuse interstellar bands. The cryogenic circulating advective multi-pass absorption cell resembles a wind tunnel; molecules evaporated from a crucible or injected using a custom gas feedthrough are entrained in a laminar flow of cryogenically cooled buffer gas and advected into the path of the synchrotron beam. This system includes a multi-pass optical White cell enabling absorption path lengths of hundreds of meters and a detection sensitivity to molecular densities on the order of 107 cm-3. A capacitively coupled radio frequency dielectric barrier discharge provides ionized and metastable buffer gas atoms for ionizing the candidate molecules via charge exchange and the Penning effect. Stronger than expected clustering of PAH molecules has slowed efforts to record gas phase PAH spectra at cryogenic temperatures, though such clusters may play a role in other interstellar phenomena.

  5. A cryogenic circulating advective multi-pass absorption cell

    Energy Technology Data Exchange (ETDEWEB)

    Stockett, M. H.; Lawler, J. E. [Department of Physics, University of Wisconsin, 1150 University Avenue, Madison, Wisconsin 53706 (United States)

    2012-03-15

    A novel absorption cell has been developed to enable a spectroscopic survey of a broad range of polycyclic aromatic hydrocarbons (PAH) under astrophysically relevant conditions and utilizing a synchrotron radiation continuum to test the still controversial hypothesis that these molecules or their ions could be carriers of the diffuse interstellar bands. The cryogenic circulating advective multi-pass absorption cell resembles a wind tunnel; molecules evaporated from a crucible or injected using a custom gas feedthrough are entrained in a laminar flow of cryogenically cooled buffer gas and advected into the path of the synchrotron beam. This system includes a multi-pass optical White cell enabling absorption path lengths of hundreds of meters and a detection sensitivity to molecular densities on the order of 10{sup 7} cm{sup -3}. A capacitively coupled radio frequency dielectric barrier discharge provides ionized and metastable buffer gas atoms for ionizing the candidate molecules via charge exchange and the Penning effect. Stronger than expected clustering of PAH molecules has slowed efforts to record gas phase PAH spectra at cryogenic temperatures, though such clusters may play a role in other interstellar phenomena.

  6. 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...

  7. Wind power

    International Nuclear Information System (INIS)

    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

  8. Convergent message passing algorithms - a unifying view

    CERN Document Server

    Meltzer, Talya; Weiss, Yair

    2012-01-01

    Message-passing algorithms have emerged as powerful techniques for approximate inference in graphical models. When these algorithms converge, they can be shown to find local (or sometimes even global) optima of variational formulations to the inference problem. But many of the most popular algorithms are not guaranteed to converge. This has lead to recent interest in convergent message-passing algorithms. In this paper, we present a unified view of convergent message-passing algorithms. We present a simple derivation of an abstract algorithm, tree-consistency bound optimization (TCBO) that is provably convergent in both its sum and max product forms. We then show that many of the existing convergent algorithms are instances of our TCBO algorithm, and obtain novel convergent algorithms "for free" by exchanging maximizations and summations in existing algorithms. In particular, we show that Wainwright's non-convergent sum-product algorithm for tree based variational bounds, is actually convergent with the right...

  9. Two-pass greedy regular expression parsing

    DEFF Research Database (Denmark)

    Grathwohl, Niels Bjørn Bugge; Henglein, Fritz; Nielsen, Lasse; Rasmussen, Ulrik Terp

    by: operating in only 2 passes; using only O(m) words of random-access memory (independent of n); requiring only kn bits of sequentially written and read log storage, where k < 1/3 m is the number of alternatives and Kleene stars in the RE; processing the input string as a symbol stream and not...... requiring it to be stored at all. Previous RE parsing algorithms do not scale linearly with input size, or require substantially more log storage and employ 3 passes where the first consists of reversing the input, or do not or are not known to produce a greedy parse. The performance of our unoptimized C...

  10. Passing off: Frameworks of Liability Debated

    OpenAIRE

    Hazel Carty

    2012-01-01

    In theory the tort of passing off is limited to the protection of traders where a misrepresentation has damaged their goodwill: the so-called classic trinity. But passing off is a protean commercial tort, with a dual development in equity and the common law and the subject at times of ad hoc interim decisions. So at times it is applied beyond the confines of this classic trinity. For this reason a rigorous academic debate is needed, to help shape this tort. Recently, Wadlow and Davis have m...

  11. Contact conditions in skin-pass rolling

    DEFF Research Database (Denmark)

    Kijima, Hideo; Bay, Niels

    2007-01-01

    The special contact conditions in skin-pass rolling of steel strip is analysed by studying plane strain upsetting of thin sheet with low reduction applying long narrow tools and dry friction conditions. An extended sticking region is estimated by an elasto-plastic FEM analysis of the plane strain...... upsetting. This sticking region causes a highly inhomogeneous elasto-plastic deformation with large influence of work-hardening and friction. A numerical analysis of skin-pass rolling shows the same contact conditions, i.e. an extended sticking region around the center of the contact zone. The calculated...

  12. The PASS project: A progress report

    International Nuclear Information System (INIS)

    The PASS project has as its goal the implementation of solutions to the foreseen data access problems of the next generation of scientific experiments. It is in the process of transitioning from an exploratory phase, where the focus has been on understanding the requirements and available technologies to an implementation phase, where detailed design work is commencing on a conunon framework for scientific applications

  13. Choisir un bon mot de passe

    OpenAIRE

    Archimbaud, Jean-Luc

    1992-01-01

    Cet article historique est un des premiers sur des recommandations de sécurité informatique au CNRS. Il était destiné à tous les utilisateurs de systèmes informatiques qui possèdent un mot de passe.

  14. Generalizing Galileo's Passe-Dix Game

    Science.gov (United States)

    Hombas, Vassilios

    2012-01-01

    This article shows a generalization of Galileo's "passe-dix" game. The game was born following one of Galileo's [G. Galileo, "Sopra le Scoperte dei Dadi" (Galileo, Opere, Firenze, Barbera, Vol. 8). Translated by E.H. Thorne, 1898, pp. 591-594] explanations on a paradox that occurred in the experiment of tossing three fair "six-sided" dice.…

  15. EMISAR single pass topographic SAR interferometer modes

    DEFF Research Database (Denmark)

    Madsen, Søren Nørvang; Skou, Niels; Woelders, Kim;

    1996-01-01

    The Danish Center for Remote Sensing (DCRS) has augmented its dual-frequency polarimetric synthetic aperture radar system (EMISAR) with single pass across-track interferometric (XTI) modes. This paper describes the system configuration, specifications and the operating modes. Analysis of data acq...

  16. State Council Passed Textile Reviving Plan

    Institute of Scientific and Technical Information of China (English)

    Dennis; K.; Zhao

    2009-01-01

    Textile reviving program is passed at the top administration level of government. To deal with the economic crisis that impacts textile industry, this New Deal characteristic of five segments of prior considerations means a lot more significant not only for China, but also for foreign business people who wish to know where to go in marketing or investment direction.

  17. Wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Yeoman, J.C. Jr.

    1978-12-01

    This evaluation of wind turbines is part of a series of Technology Evaluations of possible components and subsystems of community energy systems. Wind turbines, ranging in size from 200 W to 10 MW, are discussed as candidates for prime movers in community systems. Estimates of performance characteristics and cost as a function of rated capacity and rated wind speed are presented. Data concerning material requirements, environmental effects, and operating procedures also are given and are represented empirically to aid computer simulation.

  18. Large scale test of a novel back-pass non-perforated unglazed solar air collector

    OpenAIRE

    Paya-Marin, Miguel A.; Lim, James B P; Chen, Jian-Fei; Lawson, R. Mark; Gupta, Bhaskar Sen

    2015-01-01

    This paper describes large scale tests conducted on a novel unglazed solar air collector system. The proposed system, referred to as a back-pass solar collector (BPSC), has on-site installation and aesthetic advantages over conventional unglazed transpired solar collectors (UTSC) as it is fully integrated within a standard insulated wall panel. This paper presents the results obtained from monitoring a BPSC wall panel over one year. Measurements of temperature, wind velocity and solar irradia...

  19. Wind Energy

    Energy Technology Data Exchange (ETDEWEB)

    Ganley, Jason; Zhang, Jie; Hodge, Bri-Mathias

    2016-03-15

    Wind energy is a variable and uncertain renewable resource that has long been used to produce mechanical work, and has developed into a large producer of global electricity needs. As renewable sources of energy and feedstocks become more important globally to produce sustainable products, many different processes have started adopting wind power as an energy source. Many times this is through a conversion to hydrogen through electrolysis that allows for a more continuous process input. Other important pathways include methanol and ammonia. As the demand for sustainable products and production pathways increases, and wind power capital costs decrease, the role of wind power in chemical and energy production seems poised to increase significantly.

  20. Cross-Wind Modal Properties of Offshore Wind Turbines Identified by Full Scale Testing

    DEFF Research Database (Denmark)

    Damgaard, Mads; Ibsen, Lars Bo; Andersen, Lars Vabbersgaard; K. F. Andersen, Jacob

    Cross-wind vibrations due to wave loading misaligned with wind turbulence are often a design driver for offshore wind turbine foundations. The phenomenon is characterised by increasing fatigue loads compared to the fore-aft fatigue and a small amount of system damping since almost no aerodynamic...... damping from the blades takes place. In addition, modern offshore wind turbines are flexible structures with resonance frequencies close to environmental loads and turbine blades passing the tower. Therefore, in order to avoid conservatism during the load calculation and the design phase leading to...... additional costs, the structural response must be analysed with reliable estimations of the dynamic properties of the wind turbines. Based on a thorough investigation of “rotor-stop” tests performed on offshore wind turbines supported by a monopile foundation for different wind parks in the period 2006...

  1. Aleutian Pribilof Islands Wind Energy Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Bruce A. Wright

    2012-03-27

    Under this project, the Aleutian Pribilof Islands Association (APIA) conducted wind feasibility studies for Adak, False Pass, Nikolski, Sand Point and St. George. The DOE funds were also be used to continue APIA's role as project coordinator, to expand the communication network quality between all participants and with other wind interest groups in the state and to provide continued education and training opportunities for regional participants. This DOE project began 09/01/2005. We completed the economic and technical feasibility studies for Adak. These were funded by the Alaska Energy Authority. Both wind and hydro appear to be viable renewable energy options for Adak. In False Pass the wind resource is generally good but the site has high turbulence. This would require special care with turbine selection and operations. False Pass may be more suitable for a tidal project. APIA is funded to complete a False Pass tidal feasibility study in 2012. Nikolski has superb potential for wind power development with Class 7 wind power density, moderate wind shear, bi-directional winds and low turbulence. APIA secured nearly $1M from the United States Department of Agriculture Rural Utilities Service Assistance to Rural Communities with Extremely High Energy Costs to install a 65kW wind turbine. The measured average power density and wind speed at Sand Point measured at 20m (66ft), are 424 W/m2 and 6.7 m/s (14.9 mph) respectively. Two 500kW Vestas turbines were installed and when fully integrated in 2012 are expected to provide a cost effective and clean source of electricity, reduce overall diesel fuel consumption estimated at 130,000 gallons/year and decrease air emissions associated with the consumption of diesel fuel. St. George Island has a Class 7 wind resource, which is superior for wind power development. The current strategy, led by Alaska Energy Authority, is to upgrade the St. George electrical distribution system and power plant. Avian studies in Nikolski

  2. Harnessing Wind

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China’s wind power industry shifts into full gear The global oil crunch and environmental degradation have given rise to an ardent search for alternative and green energies throughout the world. For China, wind power is a choice one and its development is sizzling hot backed by

  3. Distributed Consensus with Finite Message Passing

    CERN Document Server

    Dash, Debashis

    2010-01-01

    Inspired by distributed resource allocation problems in dynamic topology networks, we initiate the study of distributed consensus with finite messaging passing. We first find a sufficient condition on the network graph for which no distributed protocol can guarantee a conflict-free allocation after $R$ rounds of message passing. Secondly we fully characterize the conflict minimizing zero-round protocol for path graphs, namely random allocation, which partitions the graph into small conflict groups. Thirdly, we enumerate all one-round protocols for path graphs and show that the best one further partitions each of the smaller groups. Finally, we show that the number of conflicts decrease to zero as the number of available resources increase.

  4. Wind energy.

    Science.gov (United States)

    Leithead, W E

    2007-04-15

    From its rebirth in the early 1980s, the rate of development of wind energy has been dramatic. Today, other than hydropower, it is the most important of the renewable sources of power. The UK Government and the EU Commission have adopted targets for renewable energy generation of 10 and 12% of consumption, respectively. Much of this, by necessity, must be met by wind energy. The US Department of Energy has set a goal of 6% of electricity supply from wind energy by 2020. For this potential to be fully realized, several aspects, related to public acceptance, and technical issues, related to the expected increase in penetration on the electricity network and the current drive towards larger wind turbines, need to be resolved. Nevertheless, these challenges will be met and wind energy will, very likely, become increasingly important over the next two decades. An overview of the technology is presented. PMID:17272245

  5. Interest rate pass-through in Kenya

    OpenAIRE

    Roseline N. Misati; Esman M. Nyamongo; Anne W. Kamau

    2011-01-01

    Purpose – This study aims to quantitatively measure the size and speed of monetary policy interest rate transmission to long-term interest rates in Kenya. Design/methodology/approach – The study uses autoregressive distributed lag specification re-parameterized as an error correction model and mean adjustment lag methods. Findings – The study finds incomplete pass-through of policy rates both in the short and the long run. The study also shows that it takes approximately between 11 months to ...

  6. Double-pass quantum volume hologram

    International Nuclear Information System (INIS)

    We propose a scheme for parallel, spatially multimode quantum memory for light. The scheme is based on the propagation in different directions of a quantum signal wave and strong classical reference wave, like in a classical volume hologram and the previously proposed quantum volume hologram [D. V. Vasilyev et al., Phys. Rev. A 81, 020302(R) (2010)]. The medium for the hologram consists of a spatially extended ensemble of cold spin-polarized atoms. In the absence of the collective spin rotation during the interaction, two passes of light for both storage and retrieval are required, and therefore the present scheme can be called a double-pass quantum volume hologram. The scheme is less sensitive to diffraction and therefore is capable of achieving a higher density of storage of spatial modes as compared to the previously proposed thin quantum hologram [D. V. Vasilyev et al., Phys. Rev. A 77, 020302(R) (2008)], which also requires two passes of light for both storage and retrieval. However, the present scheme allows one to achieve a good memory performance with a lower optical depth of the atomic sample as compared to the quantum volume hologram. A quantum hologram capable of storing entangled images can become an important ingredient in quantum information processing and quantum imaging.

  7. Transmission of wave energy through an offshore wind turbine farm

    DEFF Research Database (Denmark)

    Christensen, Erik Damgaard; Johnson, Martin; Sørensen, Ole Rene;

    2013-01-01

    The transmission of wave energy passing an offshore wind farm is studied. Three effects that can change the wave field are analysed, which is the A) energy dissipation due to drag resistance, B) wave reflection/diffraction from structures, and C) the effect of a modified wind field inside and on...

  8. Wind: the future is now

    Energy Technology Data Exchange (ETDEWEB)

    Ku, J.; Lew, D.; Shi Pengfei; Wallace, W.

    2005-08-01

    The ever-increasing demand for electric power in China presents an opportunity for wind power to supplement the electric power now largely generated from fossil fuels. China has highly attractive wind resources both onshore and offshore and the wind power potential is nearly double China's total energy generation capacity. The installed wind power capacity in China was 764 MW in 2004 which was a 35% increase over 2003. The Chinese government showed little interest in wind power before 2003 when it changed its policy dramatically and began issuing blocks of 100 MW concessions through public tender. Concessions guaranteed the developer a 25-year power purchase agreement with a fixed price for the first 10-15 years. In addition, VAT was cut from 17% to 8.5%. In February 2005, China passed the Renewable Energy Law with the specific purpose of supporting large-scale wind power development. There seems little doubt that China now provides real opportunities for domestic and international developers and investors.

  9. Investigation of the transient aerodynamic phenomena associated with passing manoeuvres

    Science.gov (United States)

    Noger, C.; Regardin, C.; Széchényi, E.

    2005-11-01

    Passing manoeuvres and crosswind can have significant effects on the stability of road vehicles. The transient aerodynamics, which interacts with suspension, steering geometry and driver reaction is not well understood. When two vehicles overtake or cross, they mutually influence the flow field around each other, and under certain conditions, can generate severe gust loads that act as additional forces on both vehicles. The transient forces acting on them are a function of the longitudinal and transverse spacings and of the relative velocity between the two vehicles. Wind tunnel experiments have been conducted in one of the automotive wind tunnels of the Institut Aérotechnique of Saint-Cyr l’École to simulate the transient overtaking process between two models of a simple generic automobile shape. The tests were designed to study the effects of various parameters such as the longitudinal and transverse spacing, the relative velocity and the crosswind on the aerodynamic forces and moments generated on the overtaken and overtaking vehicles. Test results characterize the transient aerodynamic side force as well as the yawing moment coefficients in terms of these parameters. Measurements of the drag force coefficient as well as the static pressure distribution around the overtaken vehicle complete the understanding. The main results indicate the aerodynamic coefficients of the overtaken vehicle to be velocity independent within the limit of the test parameters, while unsteady aerodynamic effects appear in the case of an overtaking vehicle. The mutual interference effects between the vehicles vary as a linear function of the transverse spacing and the crosswind does not really generate any new unsteady behaviour.

  10. Wind Energy

    Energy Technology Data Exchange (ETDEWEB)

    Beurskens, H.J.M. [SET Analysis, Kievitlaan 26, 1742 AD Schagen (Netherlands); Brand, A.J. [Energy research Centre of the Netherlands ECN, Unit Wind Energy, P.O. Box 1, 1755 ZG Petten (Netherlands)

    2013-02-15

    Over the years, wind energy has become a major source of renewable energy worldwide. The present chapter addresses the wind resource, which is available for exploitation for large-scale electricity production, and its specific physical properties. Furthermore, the technical options available to convert the energy of the air flow into mechanical energy and electricity are described. Specific problems of large-scale integration of wind energy into the grid as well as the present and future market developments are described in this chapter. Finally, environmental aspects are discussed briefly.

  11. Effect of Ball Mass on Dribble, Pass, and Pass Reception in 9-11-Year-Old Boys' Basketball

    Science.gov (United States)

    Arias, Jose L.; Argudo, Francisco M.; Alonso, Jose I.

    2012-01-01

    The objective of the study was to analyze the effect of ball mass on dribble, pass, and pass reception in real game situations in 9-11-year-old boys' basketball. Participants were 54 boys identified from six federated teams. The independent variable was ball mass, and dependent variables were number of dribbles, passes, and pass receptions. Three…

  12. Interest rate pass-through in Hungary

    OpenAIRE

    Csilla Horváth; Judit Krekó; Anna Naszódi

    2004-01-01

    This paper studies the pass-through from the short-term money market rate to various forint denominated bank rates in Hungary between 1997-2004. The analysis is based on linear and non-linear error correction models (ECMs), using both aggregated and bank level data. According to the linear ECM results, corporate loan rates adjust to the market rate completely and reasonably fast, whereas the adjustment of the deposit rates and household loan rates is characterised by incompleteness and/or slu...

  13. Quantum three-pass cryptography protocol

    Science.gov (United States)

    Yang, Li; Wu, Ling-An; Liu, Songhao

    2002-09-01

    We present a new kind of quantum cryptography protocol based on Shamir's three-pass protocol of classical cryptography, which allows the transmission of qubits directly and secretly via the aid of an unjammable classical channel. In this protocol we implement the encryption and decryption transformations via rotations on the Poincare sphere of the photons polarization parameters. The key technique is that Bob's encryption rotation must be commutative with Alice s decryption rotation; this means that the axes of these two rotations must be parallel. We also present a security analysis of the protocol under a man-in-the-middle attack.

  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. An experimental evaluation of multi-pass solar air heaters

    Energy Technology Data Exchange (ETDEWEB)

    Satcunanathan, S.; Persad, P.

    1980-12-01

    Three collectors of identical dimensions but operating in the single-pass, two-pass and three-pass modes were tested simultaneously under ambient conditions. It was found that the two-pass air heater was consistently better than the single-pass air heater over the day for the range of mass flow rates considered. It was also found that at a mass flow rate of 0.0095 kg s/sup -1/ m/sup -2/, the thermal performances of the two-pass and three-pass collectors were identical, but at higher flow rates the two-pass collector was superior to the three-pass collector, the superiority decreasing with increasing mass flow rate.

  16. Fabrication of seamless calandria tubes by cold pilgering route using 3-pass and 2-pass schedules

    Science.gov (United States)

    Saibaba, N.

    2008-12-01

    Calandria tube is a large diameter, extremely thin walled zirconium alloy tube which has diameter to wall thickness ratio as high as 90-95. Such tubes are conventionally produced by the 'welded route', which involves extrusion of slabs followed by a series of hot and cold rolling passes, intermediate anneals, press forming of sheets into circular shape and closing the gap by TIG welding. Though pilgering is a well established process for the fabrication of seamless tubes, production of extremely thin walled tubes offers several challenges during pilgering. Nuclear fuel complex (NFC), Hyderabad, has successfully developed a process for the production of Zircaloy-4 calandria tubes by adopting the 'seamless route' which involves hot extrusion of mother blanks followed by three-pass pilgering or two-pass pilgering schedules. This paper deals with standardization of the seamless route processes for fabrication of calandria tubes, comparison between the tubes produced by 2-pass and 3-pass pilgering schedules, role of ultrasonic test charts for control of process parameters, development of new testing methods for burst testing and other properties.

  17. Fabrication of seamless calandria tubes by cold pilgering route using 3-pass and 2-pass schedules

    International Nuclear Information System (INIS)

    Calandria tube is a large diameter, extremely thin walled zirconium alloy tube which has diameter to wall thickness ratio as high as 90-95. Such tubes are conventionally produced by the 'welded route', which involves extrusion of slabs followed by a series of hot and cold rolling passes, intermediate anneals, press forming of sheets into circular shape and closing the gap by TIG welding. Though pilgering is a well established process for the fabrication of seamless tubes, production of extremely thin walled tubes offers several challenges during pilgering. Nuclear fuel complex (NFC), Hyderabad, has successfully developed a process for the production of Zircaloy-4 calandria tubes by adopting the 'seamless route' which involves hot extrusion of mother blanks followed by three-pass pilgering or two-pass pilgering schedules. This paper deals with standardization of the seamless route processes for fabrication of calandria tubes, comparison between the tubes produced by 2-pass and 3-pass pilgering schedules, role of ultrasonic test charts for control of process parameters, development of new testing methods for burst testing and other properties

  18. Characterisation of wind farm infrasound and low-frequency noise

    Science.gov (United States)

    Zajamšek, Branko; Hansen, Kristy L.; Doolan, Con J.; Hansen, Colin H.

    2016-05-01

    This paper seeks to characterise infrasound and low-frequency noise (ILFN) from a wind farm, which contains distinct tonal components with distinguishable blade-pass frequency and higher harmonics. Acoustic measurements were conducted at dwellings in the vicinity of the wind farm and meteorological measurements were taken at the wind farm location and dwellings. Wind farm ILFN was measured frequently under stable and very stable atmospheric conditions and was also found to be dependent on the time of year. For noise character assessment, wind farm ILFN was compared with several hearing thresholds and also with the spectra obtained when the wind farm was not operating. Wind farm ILFN was found to exceed the audibility threshold at distances up to 4 km from the wind farm and to undergo large variations in magnitude with time.

  19. PASSING STANDARDIZED ASSESSMENTS WITH FADING PROMPTS

    Directory of Open Access Journals (Sweden)

    Amy Marie GREENE

    2015-11-01

    Full Text Available Introduction: No Child Left Behind Act of 2001 mandates that all students perform at a level of proficient on state assessments. This includes students with learning and intellectual disabilities who are inherently performing below grade level. Given that schools are held accountable for meeting these goals and some states are not allowing students to graduate if they do not pass the assessments, this is a large concern for students, parents, teachers, and administration Method: Forty-five students with a disability in writing or an intellectual disability participated in this quasi-experimental, single-group, pretest-posttest design that evaluated the effectiveness of the Fading Prompts through Graphic Organizers method for students with learning and intellectual disabilities in written expression as measured according to the Pennsylvania System of School Assessment. Results: Data analyses were conducted through the use of four dichotomies for percent differences, which compared teacher administered pretests and posttests, pretests and the state administered PSSA, teacher administered posttests and the PSSA, and the participants’ PSSA and the average state PSSA score. All forty-five students performed at a below basic level during baseline and a proficient level on the posttest. The learned skills generalized to the PSSA with forty-three students earning a passing score of proficient, while two students advanced to basic. Conclusion: Based on the outcomes of this study, it is highly recommended that this program be utilized at least for students with learning and intellectual disabilities until further research can be done.

  20. Wake interaction and power production of variable height model wind farms

    DEFF Research Database (Denmark)

    Vested, Malene Hovgaard; Hamilton, N.; Sørensen, Jens Nørkær; Cal, R. B.

    2014-01-01

    Understanding wake dynamics is an ongoing research topic in wind energy, since wakes have considerable effects on the power production when wind turbines are placed in a wind farm. Wind tunnel experiments have been conducted to study the wake to wake interaction in a model wind farm in tandem wit...... of a tall wind turbine to some extent passes above the standard height wind turbine. Overall the experiments show that the velocity field downstream of the exit row changes considerably when the mast height is alternating....

  1. The effect of the Sep wind park near Oosterbierum, Friesland, The Netherlands, on birds

    International Nuclear Information System (INIS)

    The study concerns 1984-1991. The wind park consists of 18 three-bladed 300 kW horizontal axis wind turbines of 35 meters height, and a rotor diameter of 30 meters, seven meteorological towers, and three cluster and control buildings. Aspects studied included disturbance of breeding, resting or feeding, and migrating birds, behavior of birds approaching the wind turbines during the day and night, and bird victims due to collision with the wind turbines and the meteorological towers. The flight behavior of birds approaching the wind park system during daylight is also dealt with. For at least a fifth of the observations it was noted whether the birds passing within 100 meters distance of a turbine showed a reaction or not. The proportion of the reactions was related to the wind park in operation or not in operation, and to the distance between the wind turbines, species, flight height, the passing distance, wind direction and wind force. Secondly the flight path of birds approaching the wind park from eastern directions during daylight (real autumn migration) and from southern directions during late afternoon (flights of gulls to night roosts) was studied in detail. Significantly more reactions (11-18%) were recorded with the wind park fully operational compared to the wind park not operational (2%). In total 2203 flight paths of birds approaching the wind park were recorded during 151 hours of observation. The test results showed that a passing distance of less or more than 100 meters of the nearest wind turbine did not affect the proportion of reactions. Several reaction types and combinations were noted, varying from gradual and calm reactions (circa 75%), and panic reactions, occurring just before or while passing the wind turbines. The reactions are shift in the flight path in the horizontal plane (30%), shift in the flight path in the vertical plane (14%), one passing attempt (87%), an accelerated wing beat (14%), an alteration of the angle of the body (21%)

  2. Galactic Winds

    Science.gov (United States)

    Veilleux, Sylvain

    Galactic winds have become arguably one of the hottest topics in extragalactic astronomy. This enthusiasm for galactic winds is due in part to the detection of winds in many, if not most, high-redshift galaxies. Galactic winds have also been invoked by theorists to (1) suppress the number of visible dwarf galaxies and avoid the "cooling catastrophe" at high redshift that results in the overproduction of massive luminous galaxies, (2) remove material with low specific angular momentum early on and help enlarge gas disks in CDM + baryons simulations, (3) reduce the dark mass concentrations in galaxies, (4) explain the mass-metallicity relation of galaxies from selective loss of metal-enriched gas from smaller galaxies, (5) enrich and "preheat" the ICM, (6) enrich the IGM without disturbing the Lyαforest significantly, and (7) inhibit cooling flows in galaxy clusters with active cD galaxies. The present paper highlights a few key aspects of galactic winds taken from a recent ARAA review by Veilleux, Cecil, &Bland-Hawthorn (2005; herafter VCBH). Readers interested in a more detailed discussion of this topic are encouraged to refer to the original ARAA article.

  3. Alongshore momentum transfer to the nearshore zone from energetic ocean waves generated by passing hurricanes

    Science.gov (United States)

    Mulligan, Ryan P.; Hanson, Jeffrey L.

    2016-06-01

    Wave and current measurements from a cross-shore array of nearshore sensors in Duck, NC, are used to elucidate the balance of alongshore momentum under energetic wave conditions with wide surf zones, generated by passing hurricanes that are close to and far from to the coast. The observations indicate that a distant storm (Hurricane Bill, 2009) with large waves has low variability in directional wave characteristics resulting in alongshore currents that are driven mainly by the changes in wave energy. A storm close to the coast (Hurricane Earl, 2010), with strong local wind stress and combined sea and swell components in wave energy spectra, has high variability in wave direction and wave period that influence wave breaking and nearshore circulation as the storm passes. During both large wave events, the horizontal current shear is strong and radiation stress gradients, bottom stress, wind stress, horizontal mixing, and cross-shore advection contribute to alongshore momentum at different spatial locations across the nearshore region. Horizontal mixing during Hurricane Earl, estimated from rotational velocities, was particularly strong suggesting that intense eddies were generated by the high horizontal shear from opposing wind-driven and wave-driven currents. The results provide insight into the cross-shore distribution of the alongshore current and the connection between flows inside and outside the surf zone during major storms, indicating that the current shear and mixing at the interface between the surf zone and shallow inner shelf is strongly dependent on the distance from the storm center to the coast.

  4. The Pension Fund passes important milestones

    CERN Multimedia

    2012-01-01

    In this column, the Chairman of the Pension Fund Governing Board (PFGB) presents the Board's latest main decisions, initiatives and accomplishments to the Fund's members and beneficiaries.   Since my last report in October, the PFGB has passed several milestones in actuarial, technical and investment matters. The PFGB has completed an analysis of a request by the European Organisation for Astronomical Research in the Southern Hemisphere (ESO) to reduce the increased cost of pension insurance for new ESO recruits that has been caused by the increased CHF/€ exchange ratio. Currently the staff of ESO are admitted to the CERN Pension Fund, pursuant to a co-operation agreement between CERN and ESO dating back to 1968. This analysis assessed the actuarial, financial, administrative and legal implications, and is scheduled to be presented to the CERN Council and the Finance Committee in December. After an open tendering process the PFGB has selected Buck Consultants Limited...

  5. The baton passes to the LHC

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    Held in the picturesque mountain setting of La Thuile in the Italian Alps, the international conference “Rencontres de Moriond” showed how the baton of discovery in the field of high-energy physics is definitely passing to the LHC experiments. In the well-known spirit of Moriond, the conference was an important platform for young students to present their latest results. The Higgs boson might well be within reach this year and the jet-quenching phenomenon might reveal new things soon…   New physics discussed over the Italian Alps during the "Les rencontres de Moriond" conference.  (Photographer: Paul Gerritsen. Adapted by Katarina Anthony) Known by physicists as one of the most important winter conferences, “Les rencontres de Moriond” are actually a series of conferences spread over two weeks covering the main themes of electroweak interactions, QCD and high-energy interactions, cosmology, gravitation, astropar...

  6. Effects of high-pass and low-pass spatial filtering on face identification.

    Science.gov (United States)

    Costen, N P; Parker, D M; Craw, I

    1996-05-01

    If face images are degraded by block averaging, there is a nonlinear decline in recognition accuracy as block size increases, suggesting that identification requires a critical minimum range of object spatial frequencies. The identification of faces was measured with equivalent Fourier low-pass filtering and block averaging preserving the same information and with high-pass transformations. In Experiment 1, accuracy declined and response time increased in a significant nonlinear manner in all cases as the spatial-frequency range was reduced. However, it did so at a faster rate for the quantized and high-passed images. A second experiment controlled for the differences in the contrast of the high-pass faces and found a reduced but significant and nonlinear decline in performance as the spatial-frequency range was reduced. These data suggest that face identification is preferentially supported by a band of spatial frequencies of approximately 8-16 cycles per face; contrast or line-based explanations were found to be inadequate. The data are discussed in terms of current models of face identification. PMID:8934690

  7. 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.

  8. A Vondrak Low Pass Filter for IMU Sensor Initial Alignment on a Disturbed Base

    Directory of Open Access Journals (Sweden)

    Zengke Li

    2014-12-01

    Full Text Available The initial alignment of the Inertial Measurement Unit (IMU is an important process of INS to determine the coordinate transformation matrix which is used in the integration of Global Positioning Systems (GPS with Inertial Navigation Systems (INS. In this paper a novel alignment method for a disturbed base, such as a vehicle disturbed by wind outdoors, implemented with the aid of a Vondrak low pass filter, is proposed. The basic principle of initial alignment including coarse alignment and fine alignment is introduced first. The spectral analysis is processed to compare the differences between the characteristic error of INS force observation on a stationary base and on disturbed bases. In order to reduce the high frequency noise in the force observation more accurately and more easily, a Vondrak low pass filter is constructed based on the spectral analysis result. The genetic algorithms method is introduced to choose the smoothing factor in the Vondrak filter and the corresponding objective condition is built. The architecture of the proposed alignment method with the Vondrak low pass filter is shown. Furthermore, simulated experiments and actual experiments were performed to validate the new algorithm. The results indicate that, compared with the conventional alignment method, the Vondrak filter could eliminate the high frequency noise in the force observation and the proposed alignment method could improve the attitude accuracy. At the same time, only one parameter needs to be set, which makes the proposed method easier to implement than other low-pass filter methods.

  9. Noise annoyance from wind turbines a review

    International Nuclear Information System (INIS)

    This study summarises present knowledge on noise perception and annoyances from wind turbines in areas were people live or spend recreation time. There are two main types of noise from a wind turbine: mechanical noise and aerodynamic noise. The aerodynamic noise emits from the rotor blades passing the air. It has a swishing character with a modulation that makes it noticeable from the background noise. This part of the wind turbine noise was found to be the most annoying. Field studies performed among people living in the vicinity of wind turbines showed that there was a correlation between sound pressure level and noise annoyance, but annoyance was also influenced by visual factors such as the attitude to wind turbines' impact on the landscape. Noise annoyance was found at lower sound pressure levels than in studies of annoyance from traffic noise. There is no scientific evidence that noise at levels created by wind turbines could cause health problems other than annoyance. No studies on noise from wind turbines in wilderness areas have been found, but the reaction to other noise sources such as aircraft have been studied. In recreational areas, the expectation of quietness is high among visitors, but wind turbines are, in contrary to aircraft, stationary and could be avoided by recreationists. The visual impact of wind turbines might though be the dominant source of annoyance. Regulations on noise from wind turbines are based on different principles. Some states, e.g. Denmark, have a special legislation concerning wind turbines, while others, like Sweden, have used recommendations originally developed for a different noise source. The noise level could either be absolute, as in Germany, or related to the background noise level as in France. This background noise level could be standardised, measured or related to wind speed

  10. Wind direction variations in the natural wind – A new length scale

    DEFF Research Database (Denmark)

    Johansson, Jens; Christensen, Silas Sverre

    2016-01-01

    During an observation period of e.g. 10min, the wind direction will differ from its mean direction for short periods of time, and a body of air will pass by from that direction before the direction changes once again. The present paper introduces a new length scale which we have labeled the angul...

  11. Astor Pass Seismic Surveys Preliminary Report

    Energy Technology Data Exchange (ETDEWEB)

    Louie, John [UNR; Pullammanappallil, Satish [Optim; Faulds, James; Eisses, Amy; Kell, Annie; Frary, Roxanna; Kent, Graham

    2011-08-05

    In collaboration with the Pyramid Lake Paiute Tribe (PLPT), the University of Nevada, Reno (UNR) and Optim re-processed, or collected and processed, over 24 miles of 2d seismic-reflection data near the northwest corner of Pyramid Lake, Nevada. The network of 2d land surveys achieved a near-3d density at the Astor Pass geothermal prospect that the PLPT drilled during Nov. 2010 to Feb. 2011. The Bureau of Indian Affairs funded additional seismic work around the Lake, and an extensive, detailed single-channel marine survey producing more than 300 miles of section, imaging more than 120 ft below the Lake bottom. Optim’s land data collection utilized multiple heavy vibrators and recorded over 200 channels live, providing a state-of-the-art reflection-refraction data set. After advanced seismic analysis including first-arrival velocity optimization and prestack depth migration, the 2d sections show clear fault-plane reflections, in some areas as deep as 4000 ft, tying to distinct terminations of the mostly volcanic stratigraphy. Some lines achieved velocity control to 3000 ft depth; all lines show reflections and terminations to 5000 ft depth. Three separate sets of normal faults appear in an initial interpretation of fault reflections and stratigraphic terminations, after loading the data into the OpendTect 3d seismic visualization system. Each preliminary fault set includes a continuous trace more than 3000 ft long, and a swarm of short fault strands. The three preliminary normal-fault sets strike northerly with westward dip, northwesterly with northeast dip, and easterly with north dip. An intersection of all three fault systems documented in the seismic sections at the end of Phase I helped to locate the APS-2 and APS-3 slimholes. The seismic sections do not show the faults connected to the Astor Pass tufa spire, suggesting that we have imaged mostly Tertiary-aged faults. We hypothesize that the Recent, active faults that produced the tufa through hotspring

  12. Wind tunnel investigation on wind turbine wakes and wind farms

    Science.gov (United States)

    Iungo, G. V.; Coëffé, J.; Porté-Agel, F.

    2012-04-01

    The interaction between atmospheric boundary layer and wind farms leads to flow modifications, which need to be deeply characterized in order to relate them to wind farm performance. The wake flow produced from a wind farm is the result of a strong interaction between multiple turbine wakes, so that the wind farm configuration turns out to be one of the dominant features to enhance power production. For the present work a wind tunnel investigation was carried out with hot-wire anemometry and velocity measurements performed with multi-hole pressure probes. The tested wind farms consist of miniature three-bladed wind turbine models. Preliminarily, the wake flow generated from a single wind turbine is surveyed, which is characterized by a strong velocity defect lying in proximity of the wind turbine hub height. The wake gradually recovers by moving downstream; the characteristics of the incoming boundary layer and wind turbulence intensity can strongly affect the wake recovery, and thus performance of following wind turbines. An increased turbulence level is typically detected downstream of each wind turbine for heights comparable to the wind turbine blade top-tip. These wake flow fluctuations produce increased fatigue loads on the following wind turbines within a wind farm, which could represent a significant hazard for real wind turbines. Dynamics of vorticity structures present in wind turbine wakes are also investigated; particular attention is paid to the downstream evolution of the tip helicoidal vortices and to oscillations of the hub vortex. The effect of wind farm layout on power production is deeply investigated. Particular emphasis is placed on studying how the flow adjusts as it moves inside the wind farm and can affect the power production. Aligned and staggered wind farm configurations are analysed, also with varying separation distances in the streamwise and spanwise directions. The present experimental results are being used to test and guide the

  13. 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.

  14. Do cold, low salinity waters pass through the Indo-Sri Lanka Channel during winter?

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, R.R.; Girishkumar, M.S.; Ravichandran, M.; Gopalakrishna, V.V.; Pankajakshan, T.

    also noticed in the intense localized mini-cold pool observed south of the ISLC, primarily driven by the surface wind and net heat flux fields during winter (Rao et al. 2008). These cooling episodes also show strong interannual variability... International Journal of Remote Sensing Vol. 32, No. 22, 20 November 2011, 7383–7398 Do cold, low salinity waters pass through the Indo-Sri Lanka Channel during winter? R. R. RAO†‡, M. S. GIRISHKUMAR§, M. RAVICHANDRAN*§, V. V. GOPALAKRISHNA¶ and P. THADATHIL...

  15. Do cold, low salinity waters pass through the Indo-Sri Lanka Channel during winter?

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, R.R.; Girishkumar, M.S.; Ravichandran, M.; Gopalakrishna, V.V.; Pankajakshan, T.

    Author version: Int. J. Remote Sens., vol.32(22); 2011; 7383-7398 Do the cold and low salinity waters pass through the Indo-Sri Lanka Channel during winter? R. R. Rao 1 , M. S. Girish Kumar 2 , M. Ravichandran 2 , V.V.Gopalakrishna 3 and P... in intense localized sea surface cooling which is primarily attributed to wind driven mixing and the associated turbulent heat losses (Kawamura, 2000, Luis and Kawamura, 2001 and 2002, Rao et al., 2008). However, no direct current measurements are available...

  16. Tracking particles by passing messages between images

    Energy Technology Data Exchange (ETDEWEB)

    Chertkov, Michael [Los Alamos National Laboratory; Kroc, Lukas [Los Alamos National Laboratory; Zdeborova, Lenka [Los Alamos National Laboratory; Krakala, Florent [ESPCI; Vergassola, M [CNRS

    2009-01-01

    Methods to extract information from the tracking of mobile objects/particles have broad interest in biological and physical sciences. Techniques based on the simple criterion of proximity in time-consecutive snapshots are useful to identify the trajectories of the particles. However, they become problematic as the motility and/or the density of the particles increases because of the uncertainties on the trajectories that particles have followed during the acquisition time of the images. Here, we report efficient methods for learning parameters of the dynamics of the particles from their positions in time-consecutive images. Our algorithm belongs to the class of message-passing algorithms, also known in computer science, information theory and statistical physics under the name of Belief Propagation (BP). The algorithm is distributed, thus allowing parallel implementation suitable for computations on multiple machines without significant inter-machine overhead. We test our method on the model example of particle tracking in turbulent flows, which is particularly challenging due to the strong transport that those flows produce. Our numerical experiments show that the BP algorithm compares in quality with exact Markov Chain Monte-Carlo algorithms, yet BP is far superior in speed. We also suggest and analyze a random-distance model that provides theoretical justification for BP accuracy. Methods developed here systematically formulate the problem of particle tracking and provide fast and reliable tools for its extensive range of applications.

  17. Single Pass Multi-component Harvester

    Energy Technology Data Exchange (ETDEWEB)

    Reed Hoskinson; J. Richard Hess

    2004-08-01

    Abstract. In order to meet the U. S. government’s goal of supplementing the energy available from petroleum by increasing the production of energy from renewable resources, increased production of bioenergy has become one of the new goals of the United States government and our society. U.S. Executive Orders and new Federal Legislation have mandated changes in government procedures and caused reorganizations within the government to support these goals. The Biomass Research and Development Initiative is a multi-agency effort to coordinate and accelerate all U.S. Federal biobased products and bioenergy research and development. The Initiative is managed by the National Biomass Coordination Office, which is staffed by both the DOE and the USDA. One of the most readily available sources of biomass from which to produce bioenergy is an agricultural crop residue, of which straw from small grains is the most feasible residue with which to start. For the straw residue to be used its collection must be energy efficient and its removal must not impact the sustainability of the growing environment. In addition, its collection must be economically advantageous to the producer. To do all that, a single pass multi-component harvester system is most desirable. Results from our first prototype suggest that current combines probably do adequate threshing and that a separate chassis can be developed that does additional separation and that is economically feasible.

  18. Anon-Pass: Practical Anonymous Subscriptions.

    Science.gov (United States)

    Lee, Michael Z; Dunn, Alan M; Katz, Jonathan; Waters, Brent; Witchel, Emmett

    2013-12-31

    We present the design, security proof, and implementation of an anonymous subscription service. Users register for the service by providing some form of identity, which might or might not be linked to a real-world identity such as a credit card, a web login, or a public key. A user logs on to the system by presenting a credential derived from information received at registration. Each credential allows only a single login in any authentication window, or epoch. Logins are anonymous in the sense that the service cannot distinguish which user is logging in any better than random guessing. This implies unlinkability of a user across different logins. We find that a central tension in an anonymous subscription service is the service provider's desire for a long epoch (to reduce server-side computation) versus users' desire for a short epoch (so they can repeatedly "re-anonymize" their sessions). We balance this tension by having short epochs, but adding an efficient operation for clients who do not need unlinkability to cheaply re-authenticate themselves for the next time period. We measure performance of a research prototype of our protocol that allows an independent service to offer anonymous access to existing services. We implement a music service, an Android-based subway-pass application, and a web proxy, and show that adding anonymity adds minimal client latency and only requires 33 KB of server memory per active user. PMID:24504081

  19. Galactic cluster winds in presence of a dark energy

    CERN Document Server

    Bisnovatyi-Kogan, G S

    2013-01-01

    We obtain a solution for the hydrodynamic outflow of the polytropic gas from the gravitating center, in presence of the uniform Dark Energy (DE). The antigravity of DE is enlightening the outflow and make the outflow possible at smaller initial temperature, at the same density. The main property of the wind in presence of DE is its unlimited acceleration after passing the critical point. In application of this solution to the winds from galaxy clusters we suggest that collision of the strongly accelerated wind with another galaxy cluster, or with another galactic cluster wind could lead to the formation of a highest energy cosmic rays.

  20. Galactic cluster winds in presence of a dark energy

    Science.gov (United States)

    Bisnovatyi-Kogan, G. S.; Merafina, M.

    2013-10-01

    We obtain a solution for the hydrodynamic outflow of the polytropic gas from the gravitating centre, in the presence of the uniform dark energy (DE). The antigravity of DE is enlightening the outflow and makes the outflow possible at smaller initial temperature, at the same density. The main property of the wind in the presence of DE is its unlimited acceleration after passing the critical point. In application of this solution to the winds from galaxy clusters, we suggest that collision of the strongly accelerated wind with another galaxy cluster, or with another galactic cluster wind, could lead to the formation of a highest energy cosmic rays.

  1. Compressive Hyperspectral Imaging via Approximate Message Passing

    Science.gov (United States)

    Tan, Jin; Ma, Yanting; Rueda, Hoover; Baron, Dror; Arce, Gonzalo R.

    2016-03-01

    We consider a compressive hyperspectral imaging reconstruction problem, where three-dimensional spatio-spectral information about a scene is sensed by a coded aperture snapshot spectral imager (CASSI). The CASSI imaging process can be modeled as suppressing three-dimensional coded and shifted voxels and projecting these onto a two-dimensional plane, such that the number of acquired measurements is greatly reduced. On the other hand, because the measurements are highly compressive, the reconstruction process becomes challenging. We previously proposed a compressive imaging reconstruction algorithm that is applied to two-dimensional images based on the approximate message passing (AMP) framework. AMP is an iterative algorithm that can be used in signal and image reconstruction by performing denoising at each iteration. We employed an adaptive Wiener filter as the image denoiser, and called our algorithm "AMP-Wiener." In this paper, we extend AMP-Wiener to three-dimensional hyperspectral image reconstruction, and call it "AMP-3D-Wiener." Applying the AMP framework to the CASSI system is challenging, because the matrix that models the CASSI system is highly sparse, and such a matrix is not suitable to AMP and makes it difficult for AMP to converge. Therefore, we modify the adaptive Wiener filter and employ a technique called damping to solve for the divergence issue of AMP. Our approach is applied in nature, and the numerical experiments show that AMP-3D-Wiener outperforms existing widely-used algorithms such as gradient projection for sparse reconstruction (GPSR) and two-step iterative shrinkage/thresholding (TwIST) given a similar amount of runtime. Moreover, in contrast to GPSR and TwIST, AMP-3D-Wiener need not tune any parameters, which simplifies the reconstruction process.

  2. Single pass kernel -means clustering method

    Indian Academy of Sciences (India)

    T Hitendra Sarma; P Viswanath; B Eswara Reddy

    2013-06-01

    In unsupervised classification, kernel -means clustering method has been shown to perform better than conventional -means clustering method in identifying non-isotropic clusters in a data set. The space and time requirements of this method are $O(n^2)$, where is the data set size. Because of this quadratic time complexity, the kernel -means method is not applicable to work with large data sets. The paper proposes a simple and faster version of the kernel -means clustering method, called single pass kernel k-means clustering method. The proposed method works as follows. First, a random sample $\\mathcal{S}$ is selected from the data set $\\mathcal{D}$. A partition $\\Pi_{\\mathcal{S}}$ is obtained by applying the conventional kernel -means method on the random sample $\\mathcal{S}$. The novelty of the paper is, for each cluster in $\\Pi_{\\mathcal{S}}$, the exact cluster center in the input space is obtained using the gradient descent approach. Finally, each unsampled pattern is assigned to its closest exact cluster center to get a partition of the entire data set. The proposed method needs to scan the data set only once and it is much faster than the conventional kernel -means method. The time complexity of this method is $O(s^2+t+nk)$ where is the size of the random sample $\\mathcal{S}$, is the number of clusters required, and is the time taken by the gradient descent method (to find exact cluster centers). The space complexity of the method is $O(s^2)$. The proposed method can be easily implemented and is suitable for large data sets, like those in data mining applications. Experimental results show that, with a small loss of quality, the proposed method can significantly reduce the time taken than the conventional kernel -means clustering method. The proposed method is also compared with other recent similar methods.

  3. Comparison and validation of full-scale data from wind measurements in the Cape Peninsula, South Africa

    DEFF Research Database (Denmark)

    Kruger, Andries C.; Goliger, Adam M.; Larsén, Xiaoli Guo;

    2014-01-01

    . These differences between the wind at the different locations are further complicated by the main strong wind mechanisms prevailing in the region, i.e. north-westerly winds from passing extratropical cyclones, mainly in the austral winter, and south-easterlies from ridging high-pressure systems, mainly...

  4. 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)

  5. Winds at the Phoenix landing site

    DEFF Research Database (Denmark)

    Holstein-Rathlou, C.; Gunnlaugsson, H.P.; Merrison, J.P.;

    2010-01-01

    frost formation are described and discussed. Two different mechanisms of dust lifting affecting the Phoenix site are proposed based on observations made with Mars Color Imager on Mars Reconnaissance Orbiter and the Telltale. The first is related to evaporation of the seasonal CO2 ice and is observed up...... to Ls ∼95°. These events are not associated with increased wind speeds. The second mechanism is observed after Ls ∼111° and is related to the passing of weather systems characterized by condensate clouds in orbital images and higher wind speeds as measured with the Telltale....

  6. Wind energy. From small wind turbines to offshore wind farms

    International Nuclear Information System (INIS)

    This bibliographical sheet presents a book in which the authors present and discuss the present and future developments, challenges and problematic of wind energy. They notably focus on offshore wind farms, their technical solutions and current French projects, with their potentials, economic, administrative and environmental aspects, their sizing issue, and so on. They also explain in detail the potential of wind energy and its conversion, present the different subsystems of a wind turbine and their operation, and describe how to build up a wind farm project. They also address the issues related to small wind turbines

  7. Establishing Pass/Fail Criteria for Bronchoscopy Performance

    DEFF Research Database (Denmark)

    Konge, Lars; Clementsen, Paul; Larsen, Klaus Richter;

    2012-01-01

    Background: Several tools have been created to assess competence in bronchoscopy. However, educational guidelines still use an arbitrary number of performed procedures to decide when basic competency is acquired. Objectives: The purpose of this study was to define pass/fail scores for two...... perform on each item of the test. Results: Using the contrasting-groups method we found a standard that would fail all novices and pass all consultants. A clear pass related to prior experience of 75 procedures. The consequences of using the extended Angoff method were also acceptable: all trainees who...... had performed less than 50 bronchoscopies failed the test and all consultants passed. A clear pass related to 80 procedures. Conclusions: Our proposed pass/fail scores for these two methods seem appropriate in terms of consequences. Prior experience with the performance of 75 and 80 bronchoscopies...

  8. Chelyabinsk fireball and Dyatlov pass tragedy

    Science.gov (United States)

    Kochemasov, G. G.

    2013-09-01

    The Chelyabinsk bolide as well as the Kunashak meteorite in 1949 (Fig. 3, black square) hit ground in ectonically peculiar place in the Ural Mountains. The main explosion was followed by a series of weaker bangs. The long Uralian fold belt (Pz) separates two subsectors (1 & 2, Fig. 1) of the Eurasian sector (1+2) of the Eastern hemisphere sectoral structure (Fig. 1). At the Pamirs-Hindukush massif (the "Pamirs' cross") meet four tectonic sectors of this structure: two opposite differently uplifted (Africa-Mediterranean ++ and Asian +) and separating them two opposite differently subsided (Eurasian - and Indooceanic - -). Tectonic bisectors divide the sectors into two differently tectonically elevated subsectors. The Ural Mountains is one of these bisectors dividing the somewhat risen East-European subsector and the relatively fallen West-Siberian one. Even more important is the sharp tectonic boundary between subsided Eurasian sector and uplifted Asian one (between 2 and 3, Fig. 1). Fig. 3 shows distribution of electrophonic bolides over USSR [1]. Observations numbers are in circles. The total of 343 observations is distributed at relevant districts; accompanied meteorites were found only in 23-24 cases; in the chart are excluded background values of 1-2 observations per district. Two areas are obviously anomalous. These of the Urals, and the Eurasia-Asia sectoral contact (Novosibirsk - Yenisei R. - Tunguska). A location in the long Uralian belt is determined by its intersection with the Timan fold belt coming from the northwest (Fig. 3). The catastrophic Dyatlov pass where nine people mysteriously died at once occurs there (triangle in Fig. 3). Mancy aborigines know this place as deadly where killing white shining spheres appear. Moreover this belt intersection is well known among hunters for UFO as the Permian triangle (Fig. 2). They meet there to observe unusual atmospheric shining and other anomalous phenomena. In the Yenisei-Tunguska-Baikal region lightning

  9. The Single Pass Multi-component Harvester

    Energy Technology Data Exchange (ETDEWEB)

    Reed Hoskinson; John R. Hess

    2004-08-01

    collection must be economically advantageous to the producer. To do all that, a single pass multi-component harvester system is most desirable. Results from our first prototype suggest that current combines probably do adequate threshing and that a separate chassis can be developed that does additional separation and that is economically feasible.

  10. Calculation of trajectory parameters of long pass in basketball.

    Directory of Open Access Journals (Sweden)

    Charikova K.M.

    2011-08-01

    Full Text Available Values of a ball's flight trajectory parameters depending on a distance of long pass, a corner of a ball's start and height of a throwing point are submitted in article. Coordinates of reference points installation for training to long pass with an optimum trajectory of a ball's flight are designed. Requirements to simulators design are determined. Corners of ball's long pass performance in various game situations are recommended.

  11. Hill Cipher pada Skema Shamir's Three Pass Protocol

    OpenAIRE

    Hasdiana

    2015-01-01

    In this study the authors use the scheme of Shamir's Three Pass Protocol for Hill Cipher operation. Scheme of Shamir's Three Pass Protocol is an attractive scheme that allows senders and receivers to communicate without the key exchange. Hill Cipher is chosen because of the key-shaped matrix, which is expected to complicate the various techniques of cryptanalyst. The results of this study indicate that the weakness of the scheme of Shamir's Three Pass Protocol for XOR operation...

  12. Tax Basis Determinations, Pass-Through Entities, and Taxpayer Noncompliance

    OpenAIRE

    James Alm; Jay A. Soled

    2014-01-01

    In the United States, one of the most popular ways to conduct business is to use a pass- through entity such as a partnership, limited liability company, or S corporation. Investor taxpayers in such pass-through entities commonly hold their ownership interest for years or decades. Over this lengthy period of time, a taxpayer's tax basis in the entity is subject to constant annual adjustments, which generally have no immediate tax consequences. However, when the pass-through entity investment ...

  13. Modified Quantum Three Pass Protocol Based on Hybrid Cryptosystem

    OpenAIRE

    Abdullah, Alharith Abdulkareem

    2015-01-01

    In this thesis we propose an enhancement to the Quantum Three-Pass Protocol (QTPP) by adding quantum authentication. After detailed analysis of all possible classical as well as quantum attack methods of the original Quantum Three-Pass Protocol, we identified, that the original Quantum Three-Pass Protocol is only vulnerable against the man-in-the-middle attack. By adding authentication and an agent called the Quantum Distribution Centre, the man-in-the-middle attack is eliminated. All communi...

  14. 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.

  15. 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...

  16. Computational analysis of flow field around Ahmed car model passing underneath a flyover

    Science.gov (United States)

    Musa, Md Nor; Osman, Kahar; Hamat, Ab Malik A.

    2012-06-01

    A flow structure around a ground vehicle has been studied by many researchers using numerous methods, either computational or experimental. However, no analysis of flow field generated by a car passing under a flyover has been carried out. One of the famous simplified models of a car is the Ahmed body that has been established to investigate the influence of the flow structure on the drag. In this paper, we investigate a flow field around Ahmed body of a single cruising condition as the vehicle passes under a flyover, using a computational method with RANS equation. The main objective of this paper is to evaluate the turbulence kinetic energy and velocity magnitude developed within the wall boundary created by the flyover, to the air flow field that is generated by the Ahmed reference car. It was observed that the simulated airflow passes the vehicle was bounded by the wall of the flyover and consequently changes the pattern of the flow field. Understanding the characteristic of this flow field under a flyover is essential if one wants to maximize the recovery of the dissipated energy which, for example, can be used to power a small vertical-axis wind turbine to produce and store electrical energy for lighting under the flyover.

  17. Wind power plants

    Energy Technology Data Exchange (ETDEWEB)

    Stiller, W.

    1980-01-01

    Wind power plants have practically faded into oblivion in Germany. These wind power plants are systems converting wind power into other usable energy forms, mainly into electric current. The irregularity of wind currents requires storage of the energy produced. The cost situation is calculated for a small wind power plant.

  18. 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…

  19. Wind-energy program

    Science.gov (United States)

    Mitchell, R.; Noun, R. J.; Flaim, T.; Deutsch, M.; Jacobs, E.; Hock, S.; Sklar, H.; Kelley, N. D.

    1982-05-01

    Progress on the wind energy tasks is summarized: program management and planning; WECS applications in nongenerating utilities; technical feasibility of stand-alone SWECS; WECS/storage assessment and options; WECS performance/value analysis; wind energy industry analysis; wind systems coordination; wind workshops; noise and television interference studies; and advanced and innovative wind energy concepts.

  20. 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…

  1. Second Order Low-Pass and High-Pass Filter Designs Using Method of Synthetic Immitance Elements

    Directory of Open Access Journals (Sweden)

    Pavel Brandstetter

    2013-01-01

    Full Text Available The paper briefly describes the basics of frequency filter design method using synthetic immittance elements with current conveyors. An introduction of the paper explains the advantages and also disadvantages of using this method. Other chapters briefly introduce a design process of simple second order low-pass and high-pass filter. A theory of current conveyors is discussed too, because they are the basic building blocs of proposed synthetic element and also active frequency filters. Finally, the particular solutions of low-pass and high-pass filters are given and verified by OrCAD PSpice simulations.

  2. Galactic cluster winds in presence of a dark energy

    OpenAIRE

    Bisnovatyi-Kogan, G. S.; Merafina, M.

    2013-01-01

    We obtain a solution for the hydrodynamic outflow of the polytropic gas from the gravitating center, in presence of the uniform Dark Energy (DE). The antigravity of DE is enlightening the outflow and make the outflow possible at smaller initial temperature, at the same density. The main property of the wind in presence of DE is its unlimited acceleration after passing the critical point. In application of this solution to the winds from galaxy clusters we suggest that collision of the strongl...

  3. Sodar data about wind profiles in Moscow city

    Directory of Open Access Journals (Sweden)

    Mikhail A. Lokoshchenko

    2009-06-01

    Full Text Available The results of wind measurements in the lowermost 500 m air layer above Moscow by Doppler sodar 'MODOS' produced by METEK firm are presented for the period from 2004 to 2008. General features both of the annual cycle of wind profiles and of the diurnal one are being discussed. In average, the highest wind speed values are observed in autumn and in winter, the least ones in spring and in summer. The recordable maximal value of the wind speed averaged over 10 minutes in Moscow city has been found as nearly 31 m/s. The distributions of wind speed values regularly show a positive asymmetry and are close to the logarithmically normal law. For the first time, seasonal dynamics of the skewness coefficient and of the kurtosis of wind distributions are analyzed. The most frequently detected wind directions are South-Western and Western-South-Western; the rarest are directions with an Eastern component. The crossover height of wind profiles varies in average from 60-80 m in autumn and in winter to nearly of 100 m in summer. For the first time, mean values of wind turning during the passing of atmospheric fronts have been received and are studied by sodar data. It was found that right-hand (clockwise turning of wind at cold fronts is more and occurs more quickly compared to warm fronts. The occlusion fronts show intermediate mean values of wind turning.

  4. Pass-Fail Grading at Berkeley: Facts and Opinions.

    Science.gov (United States)

    Suslow, Sidney

    The facts and opinions regarding pass/no pass grading at Berkeley discussed in this report are based on three sources of information. These sources include a survey of faculty conducted in the spring quarter 1970, a survey of undergraduate students in the winter quarter 1971, and the records routinely generated in the Registrar's Office for the…

  5. Teaching Strategies for the Forearm Pass in Volleyball

    Science.gov (United States)

    Casebolt, Kevin; Zhang, Peng; Brett, Christine

    2014-01-01

    This article shares teaching strategies for the forearm pass in the game of volleyball and identifies how they will help students improve their performance and development of forearm passing skills. The article also provides an assessment rubric to facilitate student understanding of the skill.

  6. Exchange Rate Pass-Through And Monetary Policy

    OpenAIRE

    Mishkin, Frederic S.

    2008-01-01

    This paper discusses what recent economic research tells us about exchange rate pass-through and what this suggests for the control of monetary policy. It first focuses on exchange rate pass-through from a macroeconomic perspective and then examines the microeconomic evidence. In light of this evidence, it then discusses the implications of exchange rate movements on the conduct of monetary policy.

  7. Challenges posed by transgender - passing within ambiguities and interrelations

    OpenAIRE

    Jules Tamas Fuetty

    2010-01-01

    This article critically interrogates current academic knowledge productions on transgender exemplified by figurations of passing. Following a deconstructivist approach, I challenge normalizations and silenced differences within dominant conceptionalizations of passing related to transgender. By investigating interconnected positionings of transgender within power relations, I will argue in favor of intersectional approaches to transgender. Regarding interrelations ofknowledge productions and ...

  8. 12 CFR 560.32 - Pass-through investments.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Pass-through investments. 560.32 Section 560.32 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY LENDING AND INVESTMENT Lending and Investment Powers for Federal Savings Associations § 560.32 Pass-through investments. (a)...

  9. Wind power; Windenergie

    Energy Technology Data Exchange (ETDEWEB)

    Molly, J.P.

    2003-07-01

    The author reports about wind power in Germany: installed capacity, number of wind turbines, average installed power, annual increase in installation, share of energy consumption, size of turbines, global development of wind energy market. (uke)

  10. Wind energy program overview

    International Nuclear Information System (INIS)

    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

  11. 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....

  12. 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...

  13. 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.

  14. 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.

  15. Development of wind energy in Morocco

    International Nuclear Information System (INIS)

    Morocco's national energy policy includes the use of renewable energy sources to lessen its reliance on fossil fuels such as coal and oil. Legislation was recently passed to increase the threshold of electrical power from 10 MW to 50 MW. Solar and wind energy are the most abundant renewable energy resources in the country and are recommended for exploitation on a large scale. Feasibility studies conducted by the Centre de Developpement des Energies Renouvelables have shown that Morocco has enough wind energy to produce electricity on a large scale and interconnect it with the national power grid. Wind energy in the country could also be used for on-site power generation in remote villages or for desalination of seawater, particularly in the southern regions of Morocco which are most affected by drought. Essaouira, Tangier, Tetouan, Tarfaya, Dakhla, Laayoune and Taza were among the regions identified with significant wind resources. The total wind energy potential for Morocco is estimated to be 2,650 GW, while the technical wind energy potential is estimated to be 1,600 GW. Several projects have been realized in the areas of electricity production, interconnection to the national power grid, decentralized rural electrification and eventually the introduction of water pumping. It was concluded that exporting green energy to Europe, via the Morocco-Spain route after the restructuring of Morocco's electricity sector will create a viable market for the medium and long-term. 3 figs

  16. 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, A.

    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.

  17. High resolution interferometer with multiple-pass optical configuration.

    Science.gov (United States)

    Ahn, Jeongho; Kim, Jong-Ahn; Kang, Chu-Shik; Kim, Jae-Wan; Kim, Soohyun

    2009-11-01

    An interferometer having fourteen times higher resolution than a conventional single-pass interferometer has been developed by making multiple-pass optical path. To embody the multiple-pass optical configuration, a two-dimensional corner cube array block was designed, and its symmetric structure minimized the measurement error. The effect from the alignment error and the imperfection of corner cube is calculated as picometer level. An experiment proves that the suggested interferometer has about 45 nm of optical resolution and its nonlinearity is about 0.5 nm in peak-to-valley. PMID:19997342

  18. NMFS Prioritization, Allocation & Scheduling System (NMFS Asset PASS)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NMFS Asset PASS is a web-based enterprise application and ORACLE database that collects research platform requests. The first release initially focused on line...

  19. Number of Migration Scenarios Passing through each HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Forest dwelling neotropical migratory birds require intact forested stopovers during migration. The number of paths that pass through a HUC highlight that huc's...

  20. Number of Migration Scenarios Passing through each HUC (future)

    Data.gov (United States)

    U.S. Environmental Protection Agency — Forest dwelling neotropical migratory birds require intact forested stopovers during migration. The number of paths that pass through a HUC highlight that huc's...

  1. Emergency wind erosion control

    Science.gov (United States)

    February through May is the critical time for wind erosion in Kansas, but wind erosion can happen any time when high winds occur on smooth, wide fields with low vegetation and poor soil structure. The most effective wind erosion control is to ensure a protective cover of residue or growing crop thro...

  2. 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.)

  3. Wind turbine state estimation

    DEFF Research Database (Denmark)

    Knudsen, Torben

    2014-01-01

    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...

  4. Sparse Multinomial Logistic Regression via Approximate Message Passing

    OpenAIRE

    Byrne, Evan; Schniter, Philip

    2015-01-01

    For the problem of multi-class linear classification and feature selection, we propose approximate message passing approaches to sparse multinomial logistic regression. First, we propose two algorithms based on the Hybrid Generalized Approximate Message Passing (HyGAMP) framework: one finds the maximum a posteriori (MAP) linear classifier and the other finds an approximation of the test-error-rate minimizing linear classifier. Then we design computationally simplified variants of these two al...

  5. Exchange Rate Pass-Through in the Euro Area

    OpenAIRE

    Rajmund MIRDALA

    2015-01-01

    Time-varying exchange rate pass-through effects to domestic prices under fixed euro exchange rate perspective represent one of the most challenging implications of the common currency. The problem is even more crucial when examining crisis related redistributive effects associated with relative price changes. The degree of the exchange rate pass-through to domestic prices reveals its role as the external price shocks absorber especially in the situation when the leading path of exchange rates...

  6. Interest rate pass-through estimates from vector autoregressive models

    OpenAIRE

    Burgstaller, Johann

    2005-01-01

    The empirical literature on interest rate transmission presents diverse and sometimes conflicting estimates. By discussing methodological and specification-related issues, the results of this paper contribute to the understanding of these differences. Eleven Austrian bank lending and deposit rates are utilized to illustrate the pass-through of impulses from monetary policy and banks’ cost of funds. Results from vector autoregressions suggest that the long-run pass-through is higher for moveme...

  7. Gestalt-like representations hijack Chunk-and-Pass processing.

    Science.gov (United States)

    Dumitru, Magda L

    2016-01-01

    Christiansen & Chater (C&C) make two related and somewhat contradictory claims, namely that the ever abstract language representations built during Chunk-and-Pass processing allow for ever greater interference from extra-linguistic information, and that it is nevertheless the language system that re-codes incoming information into abstract representations. I analyse these claims and discuss evidence suggesting that Gestalt-like representations hijack Chunk-and-Pass processing. PMID:27562687

  8. Safe and Efficient Data Sharing for Message-Passing Concurrency

    OpenAIRE

    Morandi, Benjamin; Nanz, Sebastian; Meyer, Bertrand

    2014-01-01

    Message passing provides a powerful communication abstraction in both distributed and shared memory environments. It is particularly successful at preventing problems arising from shared state, such as data races, as it avoids sharing in general. Message passing is less effective when concurrent access to large amounts of data is needed, as the overhead of messaging may be prohibitive. In shared memory environments, this issue could be alleviated by supporting direct access to shared data; bu...

  9. Terrorismihirm sunnib muretsema kalleid mikrokiibiga passe / Andrus Karnau

    Index Scriptorium Estoniae

    Karnau, Andrus

    2005-01-01

    Alates 1. septembrist 2006 peavad kõik EL-i liikmesriigid hakkama väljastama mikrokiibiga varustatud passe, mille hinnaks võib kujuneda kuni 1000 krooni ja kehtivus lüheneb viiele aastale. Mikrokiip sisaldab inimese biomeetrilisi andmeid - esialgu vaid näokujutist, alates 2008. aastast näpujälgi ning hiljem ka andmeid silmaiirise ja juuksevärvi kohta. Lisa: Biomeetriline pass peidab intiimseid isikuandmeid. Kommenteerib Kohtuekspertiisi ja Kriminalistika Keskuse infojuht Aivar Pau

  10. Single-pass multi-view volume rendering

    OpenAIRE

    Hübner, T; Pajarola, R.

    2007-01-01

    In this paper, we introduce a new direct volume rendering (DVR) algorithm for multi-view auto-stereoscopic displays. Common multi-view methods perform multi-pass rendering (one pass for each view) and subsequent image compositing and masking for generating multiple views. The rendering time increases therefore linearly with the number of views, but sufficient frame-rates are achieved by sub-resolution rendering, at the expense of degraded image quality. To overcome these disadvantages for DVR...

  11. Wind Loads on Structures

    DEFF Research Database (Denmark)

    Dyrbye, Claes; Hansen, Svend Ole

    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...... background material. It derives the theoretical background of wind loaded structures and gives practical applications for a large variety of structures, such as low rise static structures, buildings, chimneys and cable-supported bridges. The European Prestandard on Wind Actions, ENV 1991-2-4, is used...

  12. Transbronchial needle aspirates: how many passes per target site?

    Science.gov (United States)

    Diacon, A H; Schuurmans, M M; Theron, J; Brundyn, K; Louw, M; Wright, C A; Bolliger, C T

    2007-01-01

    Transbronchial needle aspiration is a bronchoscopic sampling method for a variety of bronchial and pulmonary lesions. The present study investigated whether and how serial needle passes contribute to the yield of transbronchial needle aspiration at specific target sites. A total of 1,562 needle passes, performed at 374 target sites in 245 patients with neoplastic disease (82%), non-neoplastic disease (15%) or undiagnosed lesions (3%), were prospectively recorded and rated for anatomical location, size, bronchoscopic appearance and underlying disease. Positive aspirates were obtained in 75% of patients and at 68% of target sites. A diagnosis was established with the first, second, third and fourth needle pass at 64, 87, 95 and 98% of targets, respectively. The absolute yield varied strongly with target site features, but the stepwise increment to the maximum yield provided by serial passes was similar across target sites. In conclusion, three transbronchial needle passes per site are appropriate when only a tissue diagnosis is sought and when alternative sites or sampling modalities are available. At least four or five passes should be carried out at lymph node stations critical for the staging of lung cancer. PMID:17005579

  13. An Icelandic wind atlas

    Science.gov (United States)

    Nawri, Nikolai; Nína Petersen, Gudrun; Bjornsson, Halldór; Arason, Þórður; Jónasson, Kristján

    2013-04-01

    While Iceland has ample wind, its use for energy production has been limited. Electricity in Iceland is generated from renewable hydro- and geothermal source and adding wind energy has not be considered practical or even necessary. However, adding wind into the energy mix is becoming a more viable options as opportunities for new hydro or geothermal power installation become limited. In order to obtain an estimate of the wind energy potential of Iceland a wind atlas has been developed as a part of the Nordic project "Improved Forecast of Wind, Waves and Icing" (IceWind). The atlas is based on mesoscale model runs produced with the Weather Research and Forecasting (WRF) Model and high-resolution regional analyses obtained through the Wind Atlas Analysis and Application Program (WAsP). The wind atlas shows that the wind energy potential is considerable. The regions with the strongest average wind are nevertheless impractical for wind farms, due to distance from road infrastructure and power grid as well as harsh winter climate. However, even in easily accessible regions wind energy potential in Iceland, as measured by annual average power density, is among the highest in Western Europe. There is a strong seasonal cycle, with wintertime power densities throughout the island being at least a factor of two higher than during summer. Calculations show that a modest wind farm of ten medium size turbines would produce more energy throughout the year than a small hydro power plants making wind energy a viable additional option.

  14. Quick start file for the panel "Labour market and social security" (PASS) : analysing the PASS data using SPSS/PASW

    OpenAIRE

    Fuchs, Benjamin; Lödel, Sarah; Otto, Michael

    2015-01-01

    This FDZ-Methodenreport is meant to help users of SPSS/PASW handling the data of the Panel Study "Labour Market and Social Security" (PASS). It uses practical examples as can be found in the User Guide of PASS (Bethmann/Fuchs/Wurdack, 2013: Part II), which was written with a focus on STATA users. Therefore, it draws heavily on the work of Gebhardt/Bethmann (2013a), Gebhardt/Bethmann (2013b), Gebhardt/Bethmann (2013c) and Trappmann (2013).

  15. Second order low-pass and high-pass filter designs using method of synthetic immitance elements

    OpenAIRE

    Pavel Brandstetter; Lukas Klein

    2013-01-01

    The paper briefly describes the basics of frequency filter design method using synthetic immittance elements with current conveyors. An introduction of the paper explains the advantages and also disadvantages of using this method. Other chapters briefly introduce a design process of simple second order low-pass and high-pass filter. A theory of current conveyors is discussed too, because they are the basic building blocs of proposed synthetic element and also active frequency filters. Finally...

  16. 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...... 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....

  17. Wind energy development policy and prospects in Lithuania

    Energy Technology Data Exchange (ETDEWEB)

    Markevicius, Antanas; Katinas, Vladislovas; Marciukaitis, Mantas [Lithuanian Energy Institute, Laboratory of Renewable Energy, Breslaujos str. 3, LT-44403 Kaunas (Lithuania)

    2007-10-15

    According to the EU Directive 2001/77/EC 7% of all electricity production is to be generated from renewable energy sources (RES) in Lithuania in 2010. Electricity production from RES is determined by hydro, biomass and wind energy resources in Lithuania. Further development of hydro power plants is limited by environmental restrictions, therefore priority is given to wind energy development. The aim of this paper is to show estimation of the maximum wind power penetration in the Lithuanian electricity system using such criteria as wind potential, possibilities of the existing electricity network, possible environmental impact, and social and economical aspects. Generalization of data from the meteorological stations and special measurements shows that the highest average wind speed in Lithuanian territory is in the coastal region and at 50 m above ground level reaches 6.4 m/s. In regard to wind resource distribution in this region, arrangement of electricity grid and environment protection requirements, six zones have been determined for wind power plant construction. Calculations have shown that the largest total installed capacity of wind farms, which could cause no significant increase in power transmission expenses, is 170 MW. The threshold, which cannot be passed without capital reconstruction of electricity network, is 500 MW of total capacity of wind farms. (author)

  18. NUMERICAL SIMULATION ANALYSIS OF EXTERNAL FLOW FIELD OF WAGON-SHAPED CAR AT THE MOMENT OF PASSING

    Institute of Scientific and Technical Information of China (English)

    GU Zhengqi; HE Yibin; ZHOU Wei; JIANG Bo

    2008-01-01

    In the course of studying on aerodynamic change and its effect on steering stability and controllability of an automobile in passing, because of multi interaction streams, it is difficult to use traditional methods, such as wind tunnel test and road test. If the passing process of an automobile is divided into many time segments, so as to avoid the use of moving mesh which takes large calculation resource and CPU processing time in calculating, the segments are simulated with computational fluid dynamics (CFD) method, then the approximate computational results about external flow field will be obtained. On the basis of the idea, the change of external flow field of wagon-shaped car at the moment of passing is simulated through solving three-dimensional, steady and uncompressible N-S equations with finite volume method. Numerical simulation analysis of side force coefficient, stream lines, body surface pressure distribution of wagon-shaped car are presented and a preliminary discussion of aerodynamic characteristics of correlative situations is obtained. Finally, the Cs -x/l curve of side force coefficient(Cs) of car following relative distance (x/l) between cars is obtained. By comparison, the curve is coincident well with the experimental data,which shows creditability of numerical simulation methods presented.Key words: External flow field Passing Numerical simulation Side force coefficient

  19. Wind turbine wakes for wind energy

    OpenAIRE

    Gunner C. Larsen; Crespo Martínez, Antonio

    2011-01-01

    During recent years, wind energy has moved from an emerging technology to a nearly competitive technology. This fact, coupled with an increasing global focus on environmental concern and a political desire of a certain level of diversification in the energy supply, ensures wind energy an important role in the future electricity market. For this challenge to be met in a cost-efficient way, a substantial part of new wind turbine installations is foreseen to be erected in big onshore or offshore...

  20. Wind speed forecasting for wind energy applications

    Science.gov (United States)

    Liu, Hong

    With more wind energy being integrated into our grid systems, forecasting wind energy has become a necessity for all market participants. Recognizing the market demands, a physical approach to site-specific hub-height wind speed forecasting system has been developed. This system is driven by the outputs from the Canadian Global Environmental Multiscale (GEM) model. A simple interpolation approach benchmarks the forecasting accuracy inherited from GEM. Local, site specific winds are affected on a local scale by a variety of factors including representation of the land surface and local boundary-layer process over heterogeneous terrain which have been a continuing challenge in NWP models like GEM with typical horizontal resolution of order 15-km. In order to resolve these small scale effects, a wind energy industry standard model, WAsP, is coupled with GEM to improve the forecast. Coupling the WAsP model with GEM improves the overall forecasts, but remains unsatisfactory for forecasting winds with abrupt surface condition changes. Subsequently in this study, a new coupler that uses a 2-D RANS model of boundary-layer flow over surface condition changes with improved physics has been developed to further improve the forecasts when winds coming from a water surface to land experience abrupt changes in surface conditions. It has been demonstrated that using vertically averaged wind speeds to represent geostrophic winds for input into the micro-scale models could reduce forecast errors. The hub-height wind speed forecasts could be further improved using a linear MOS approach. The forecasting system has been evaluated, using a wind energy standard evaluation matrix, against data from an 80-m mast located near the north shore of Lake Erie. Coupling with GEM-LAM and a power conversion model using a theoretical power curve have also been investigated. For hub-height wind speeds GEM appears to perform better with a 15-Ian grid than the high resolution GEM-2.5Ian version at the

  1. 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

  2. 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 re...... constraints at the same time. In this way, the resulting airfoil should remain a realistic candidate for wind turbine applications and comparisons between the original and optimized airfoils remain fair. As for the verification in wind tunnel, the reader is referred to Section 7.3....

  3. 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

    ... Energy Regulatory Commission Alta Wind VII, LLC, Alta Wind IX, LLC, Alta Wind X, LLC, Alta Wind XI, LLC... Practice and Procedure, 18 CFR 385.207, Alta Wind VII, LLC, Alta Wind IX, LLC, Alta Wind X, LLC, Alta Wind... to firm transmission rights to the capacity of three transmission lines to be constructed by Alta...

  4. Development of Message Passing Routines for High Performance Parallel Computations

    Science.gov (United States)

    Summers, Edward K.

    2004-01-01

    Computational Fluid Dynamics (CFD) calculations require a great deal of computing power for completing the detailed computations involved. In an effort shorten the time it takes to complete such calculations they are implemented on a parallel computer. In the case of a parallel computer some sort of message passing structure must be used to communicate between the computers because, unlike a single machine, each computer in a parallel computing cluster does not have access to all the data or run all the parts of the total program. Thus, message passing is used to divide up the data and send instructions to each machine. The nature of my work this summer involves programming the "message passing" aspect of the parallel computer. I am working on modifying an existing program, which was written with OpenMP, and does not use a multi-machine parallel computing structure, to work with Message Passing Interface (MPI) routines. The actual code is being written in the FORTRAN 90 programming language. My goal is to write a parameterized message passing structure that could be used for a variety of individual applications and implement it on Silicon Graphics Incorporated s (SGI) IRIX operating system. With this new parameterized structure engineers would be able to speed up computations for a wide variety of purposes without having to use larger and more expensive computing equipment from another division or another NASA center.

  5. 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.

  6. 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....

  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. 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.

  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. Arctic wind energy

    International Nuclear Information System (INIS)

    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.)

  11. Maximizing Number of Passes in Recirculating Energy Recovery Linacs

    Science.gov (United States)

    Bogacz, S. Alex

    2016-03-01

    The next generation of high energy recirculating linear accelerators (RLAs) will rely on the energy recovery (ER) process for their extreme high current operation. Here, we discuss optimum design of multi-pass linac optics for an RLA based on a large scale superconducting linac. Initial strategy used in the design of 60 GeV, 6 pass RLA for the LHeC, has been extended to 10 passes for the proposed CEBAF ER experiment. The presented optimization scheme addresses overall beam transport performance, as well as specific beam dynamics issues, such as, beam stability due to collective effects. Work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.

  12. The effects of low pass filters of peak ground acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Park, Dong Hee; Chang, Chun Joong [KHNP Central Resrach Institute, Daejeon (Korea, Republic of)

    2012-10-15

    This paper studies actual records of earthquake waveforms to analyze attenuation characteristics of peak ground Acceleration(PGA) resulting from low pass filters. For this purpose, we acquired raw data of major earthquakes around the world including the Western U.S., Taiwan, Italy, Iran, and Turkey etc., and analyzed peak ground acceleration(PGA) values before and after passing through low pass filters. In addition, we presented results of analyzing case studies, such as the automatic shutdown of a nuclear power plant in the Niigata Prefecture, Japan on July 16, 2007 when an earthquake (magnitude 6.8) shook the plant beyond its design basis, and the earthquake (magnitude 9.0) that occurred off the Pacific coast of Tohoku on March 11, 2011.

  13. Design and Development of Low Pass Filter at 60 GHz

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar Shah

    2013-07-01

    Full Text Available This paper describes the design and development of low pass filter (LPF at 60 GHz. The present design uses stepped impedance method in suspended strip line. The design is modeled and optimized using CST (Computer Simulation Technology microwave studio. The design of a filter types that Tchebysheve 0.1 dB ripple in the passband with the standard bandwidth of 2% and 30 dB attenuation at 94 GHz. The 60 GHz low pass filter exhibits an insertion loss of 1 dB with 3 dB relative bandwidth at a cut-off frequency of 60 GHz and the return loss is better than -18 dB at a cut-off frequency. The designed and fabricated low pass filter shows the good performance for planar integrated millimeter-wave circuits

  14. A First-Order One-Pass CPS Transformation

    DEFF Research Database (Denmark)

    Danvy, Olivier; Nielsen, Lasse Reichstein

    We present a new transformation of call-by-value lambdaterms into continuation-passing style (CPS). This transformation operates in one pass and is both compositional and first-order. Because it operates in one pass, it directly yields compact CPS programs that are comparable to what one would...... write by hand. Because it is compositional, it allows proofs by structural induction. Because it is first-order, reasoning about it does not require the use of a logical relation. This new CPS transformation connects two separate lines of research. It has already been used to state a new and simpler...... correctness proof of a direct-style transformation, and to develop a new and simpler CPS transformation of control-flow information....

  15. A First-Order One-Pass CPS Transformation

    DEFF Research Database (Denmark)

    Danvy, Olivier; Nielsen, Lasse Reichstein

    2003-01-01

    We present a new transformation of λ-terms into continuation-passing style (CPS). This transformation operates in one pass and is both compositional and first-order. Previous CPS transformations only enjoyed two out of the three properties of being first-order, one-pass, and compositional, but the...... new transformation enjoys all three properties. It is proved correct directly by structural induction over source terms instead of indirectly with a colon translation, as in Plotkin's original proof. Similarly, it makes it possible to reason about CPS-transformed terms by structural induction over...... source terms, directly.The new CPS transformation connects separately published approaches to the CPS transformation. It has already been used to state a new and simpler correctness proof of a direct-style transformation, and to develop a new and simpler CPS transformation of control-flow information....

  16. A First-Order One-Pass CPS Transformation

    DEFF Research Database (Denmark)

    Danvy, Olivier; Nielsen, Lasse Reichstein

    We present a new transformation of λ-terms into continuation-passing style (CPS). This transformation operates in one pass and is both compositional and first-order. Previous CPS transformations only enjoyed two out of the three properties of being first-order, one-pass, and compositional, but the...... new transformation enjoys all three properties. It is proved correct directly by structural induction over source terms instead of indirectly with a colon translation, as in Plotkin's original proof. Similarly, it makes it possible to reason about CPS-transformed terms by structural induction over...... source terms, directly.The new CPS transformation connects separately published approaches to the CPS transformation. It has already been used to state a new and simpler correctness proof of a direct-style transformation, and to develop a new and simpler CPS transformation of control-flow information....

  17. The ABL due to a Mountain Pass and Coriolis Effect

    OpenAIRE

    Grisogono, B.; Enger, L.; Belušić, D.

    2005-01-01

    Abstract: Idealized airflow over a mountain with a pass is studied using a numerical mesoscale model with a trustful higher-order turbulence parameterization scheme. A uniformly stratified inflow of 8 m/s over mountain, 100km x 20km x 1km, yields Froude number 0.6, while Rossby number along the flow ranges from 7.6 to infinity. A pass drops the mountain top to ~ 400m locally increasing Froude number and modifying the overall wave breaking and the ABL. In the presence of the Earth rotation, f ...

  18. Delay Bound: Fractal Traffic Passes through Network Servers

    Directory of Open Access Journals (Sweden)

    Ming Li

    2013-01-01

    Full Text Available Delay analysis plays a role in real-time systems in computer communication networks. This paper gives our results in the aspect of delay analysis of fractal traffic passing through servers. There are three contributions presented in this paper. First, we will explain the reasons why conventional theory of queuing systems ceases in the general sense when arrival traffic is fractal. Then, we will propose a concise method of delay computation for hard real-time systems as shown in this paper. Finally, the delay computation of fractal traffic passing through severs is presented.

  19. Loss of European silver eel passing a hydropower station

    DEFF Research Database (Denmark)

    Pedersen, Michael Ingemann; Jepsen, Niels; Aarestrup, Kim; Koed, Anders; Pedersen, Stig; Økland, F.

    2012-01-01

    The aim of this study was to assess escapement success of silver eels, Anguilla anguilla (L.), in a lowland river while passing a reservoir and a hydropower station. It was hypothesized that passage success would be lowest at the hydropower station and that survival and migration speed would be...... within the study period, only 23% of the tagged eels reached the tidal limit, mainly due to difficulties in passing the hydropower dam. With such high loss-rates, the escapement goals set in the management plan cannot be achieved...

  20. Algorithm on robot soccer pass and shoot a ball

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Introduces of robot soccer's competition software of Harbin Institute of Technology(HIT), the con cept of running range and the method of calculating the running range for both the opponent and our teammates according to the distances Between the ball and robot soccers, and therefore the method of calculating the angle that the robot passes or shoots the ball according to the running ranges of both sides. And gives the examples of passing the ball when the ball's position is in the backcourt and shooting the ball when the ball's position is in the frontcourt.

  1. Message-Passing Interface - Selected Topics and Best Practices

    OpenAIRE

    Janetzko, Florian

    2014-01-01

    The Message-Passing Interface (MPI) is a widely-used standard library for programming parallel applications using the distributed-memory model. In the first part of this talk we will give a short overview over concepts and properties of modern HPC hardware architectures as well as basic programming concepts. A brief introduction into a design strategy for parallel algorithms is presented.The focus of the second part will be on the Message-Passing interface. After a short overview over general...

  2. Continuum Mechanical Modelling of Skin-pass Rolling

    DEFF Research Database (Denmark)

    Kijima, Hideo; Bay, Niels

    2007-01-01

    The special contact conditions in skin-pass rolling of steel strip is analyzed by studying plane strain upsetting of thin sheet with low reduction applying long narrow tools and dry friction conditions. An extended sticking region is estimated by an elasto-plastic FEM analysis of the plane strain...... upsetting. This sticking region causes a highly inhomogeneous elasto-plastic deformation with large influence of work-hardening and friction. A numerical analysis of skin-pass rolling shows the same contact conditions, i.e. an extended sticking region around the center of the contact zone. The calculated...

  3. 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.

  4. 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...

  5. WindWaveFloat

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, Alla [Principle Power Inc., Berkeley, CA (United States)

    2011-11-01

    Presentation from the 2011 Water Peer Review includes in which principal investigator Alla Weinstein discusses project progress in development of a floating offshore wind structure - the WindFloat - and incorporation therin of a Spherical Wave Energy Device.

  6. Of Winds and Waves

    CERN Document Server

    Kirk, John G

    2011-01-01

    Recent work on the properties of superluminal waves in pulsar winds is summarized. It is speculated that these waves play an important role in the termination shock that divides the wind from the surrounding nebula.

  7. NESDIS VIIRS Polar Winds

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains the Level 3 Polar Winds Northern and Southern Hemisphere datasets. The Level 3 Polar Winds data from VIIRS for the Arctic and Antarctic from...

  8. Urban Wind Energy

    DEFF Research Database (Denmark)

    Beller, Christina

    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....... However, an overview of the energy content of the wind in cities and how consequently turbines shall be designed for such wind climates is lacking. The objective of the present work is to deliver an objective and fundamental overview of the social, practical and physical conditions relevant for the...... important for the implementation of wind energy conversion systems are the macro and micro wind climate, the siting within a micro wind climate and the choice of a wind turbine model most appropriate for the selected site. In the frame of this work, all these important elements are analyzed and a row of...

  9. BOEM Wind Planning Areas

    Data.gov (United States)

    Bureau of Ocean Energy Management, Department of the Interior — This data set represents the most recent changes for the Wind Development Planning Areas in the Atlantic. Wind Planning Areas in this dataset represent up to six...

  10. 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....

  11. 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....

  12. 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)

  13. 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...... operating expenditures, which, along with the energy produced, determine the cost of energy. A better system-level understanding of wind farms is hence of critical importance to the wind-energy industry....

  14. An investigation of the levels of electromagnetic radiation generated by wind turbines

    International Nuclear Information System (INIS)

    The issue of electromagnetic interference is arising with some regularity as various wind energy projects throughout the UK reach the stage where local authority planning approval is sought. To many of the parties involved, wind turbines represent an unknown quantity and hence objections to their siting must be expected. Wind turbines may cause electromagnetic interference through two quite distinct processes. The first occurs when the wind turbine scatters electromagnetic signals passing through the area of the site and essentially, provides a second path between the transmitter and receiver of the signal. The second source of interference arises when signals generated within the wind turbine itself affect communications equipment or, indeed, any electronic circuitry. A case in point is a wind farm project under development by Bonython Estates of Cornwall. The aim of this project was to investigate the emissions from the wind turbines proposed for the Bonython development. This was achieved by means of field measurements on existing installations. (author)

  15. Offshore wind energy developments

    OpenAIRE

    Stolpe, Mathias; Buhl, Thomas; Sumer, B. Mutlu; Kiil, Søren; Holbøll, Joachim; Piirainen, Kalle

    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.

  16. 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....

  17. Sensing the wind profile

    DEFF Research Database (Denmark)

    Pena Diaz, Alfredo

    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 Høvsøre, Denmark. Both sensing techniques show a high degree of agreement for wind speed measurements performed at either sites. The wind speed...

  18. Wind and Yaw correlation

    DEFF Research Database (Denmark)

    Vesth, Allan; 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...

  19. 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.

  20. Wind and Yaw correlation

    DEFF Research Database (Denmark)

    Kock, Carsten Weber; Vesth, Allan

    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....

  1. 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.

  2. Denmark Wind Energy Programme

    OpenAIRE

    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.

  3. Wind farm electrical system

    Science.gov (United States)

    Erdman, William L.; Lettenmaier, Terry M.

    2006-07-04

    An approach to wind farm design using variable speed wind turbines with low pulse number electrical output. The output of multiple wind turbines are aggregated to create a high pulse number electrical output at a point of common coupling with a utility grid network. Power quality at each individual wind turbine falls short of utility standards, but the aggregated output at the point of common coupling is within acceptable tolerances for utility power quality. The approach for aggregating low pulse number electrical output from multiple wind turbines relies upon a pad mounted transformer at each wind turbine that performs phase multiplication on the output of each wind turbine. Phase multiplication converts a modified square wave from the wind turbine into a 6 pulse output. Phase shifting of the 6 pulse output from each wind turbine allows the aggregated output of multiple wind turbines to be a 24 pulse approximation of a sine wave. Additional filtering and VAR control is embedded within the wind farm to take advantage of the wind farm's electrical impedence characteristics to further enhance power quality at the point of common coupling.

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

    Directory of Open Access Journals (Sweden)

    Ju Feng

    2015-04-01

    Full Text Available 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 at Horns Rev and three different joint distributions are obtained, which all fit the measurement data quite well in terms of the coefficient of determination . 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.

  5. Wind: French revolutions

    International Nuclear Information System (INIS)

    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

  6. 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...

  7. STRUCTURE OF ECAP ALUMINIUM AFTER DIFFERENT NUMBER OF PASSES

    Directory of Open Access Journals (Sweden)

    Lucia Ilucová

    2011-05-01

    Full Text Available The structure of high purity (99.99% aluminium processed by equal channel angular pressing in the as pressed state after different number of passes was examined using various stereological methods. An extreme inhomogeneity and complicated anisotropy was observed along the body of rod-like specimens.

  8. The ISO 5-pass authentication in χ-Spaces

    DEFF Research Database (Denmark)

    Cáccamo, Mario J.; Crazzolara, Federico; Milicia, Giuseppe

    2002-01-01

    We implement the ISO 5-pass authentication protocol and study its correctness using the χ-Space framework. χ-Spaces is a novel domain specific programming language designed for developing protocols and in particular security protocols. χ-Spaces programming language is an implementation of SPL...

  9. Analysis and Design of Binary Message-Passing Decoders

    DEFF Research Database (Denmark)

    Lechner, Gottfried; Pedersen, Troels; Kramer, Gerhard

    2012-01-01

    Binary message-passing decoders for low-density parity-check (LDPC) codes are studied by using extrinsic information transfer (EXIT) charts. The channel delivers hard or soft decisions and the variable node decoder performs all computations in the L-value domain. A hard decision channel results i...

  10. Vehicle dynamic effects in the course of passing over turnouts

    Directory of Open Access Journals (Sweden)

    Zelenka J.

    2007-11-01

    Full Text Available For the quantification of vehicle dynamic effects at passing over turnouts at a higher speed there was developed a methodology for evaluating of acceleration measured on vehicle axle boxes in the year 2003. The methodology is based on statistical evaluation of lateral and vertical acceleration measured values at passing over both critical parts of a turnout (tongue, frog. The created methodology was used for investigation of vehicle dynamic effects by running at speed up to 230 km/h in the year 2004 in terms of high speed tests of tilting-body unit class 680 CD. There was found relatively high values of dynamic effects already at a speed 160 km/h. In terms of tilting-body unit class 680 tests at a higher speed in curves of chosen track lines of 1st and 2nd corridor of Czech Railways there was carried out also verification of curved turnouts state according to methodology mentioned above with a view to possibility of speed increasing at curved throats of chosen stations. Lateral vehicle dynamic effects at passing over a curved turnout frog area were evaluated. There were carried out simulation calculations of vehicle passing over a turnout based on measured geometric parameters of wheelset as well as chosen turnouts. Results of the calculations were compared with measurements. The increased vehicle dynamic effects found in pulsed beats character influence negatively the turnouts part (not only wheel contacting parts as well as operating life all unsuspended parts of vehicles.

  11. Band-Pass Amplifier Without Discrete Reactance Elements

    Science.gov (United States)

    Kleinberg, L.

    1984-01-01

    Inherent or "natural" device capacitance exploited. Band-Pass Circuit has input impedance of equivalent circuit at frequencies much greater than operational-amplifier rolloff frequency. Apparent inductance and capacitance arise from combined effects of feedback and reactive component of amplifier gain in frequency range.

  12. Modelling of a one pass smoke tube boiler

    DEFF Research Database (Denmark)

    Karstensen, Claus M. S.; Sørensen, Kim

    2004-01-01

    A nonlinear state-space model with five states describing a one pass smoke tube boiler has been formulated. By means of mass- and energy-balance the model describes the dynamics of the Furnace, the Convection Zone and the Water/Steam Part and the three sub models are merged into an overall model....

  13. Thin-disk laser multi-pass amplifier

    CERN Document Server

    Schuhmann, K; Graf, T; Hänsch, T W; Kirch, K; Kottmann, F; Pohl, R; Taqqu, D; Voß, A; Weichelt, B; Antognini, A

    2015-01-01

    In the context of the Lamb shift measurement in muonic helium we developed a thin-disk laser composed of a Q-switched oscillator and a multi-pass amplifier delivering pulses of 150 mJ at a pulse duration of 100 ns. Its peculiar requirements are stochastic trigger and short delay time (< 500 ns) between trigger and optical output. The concept of the thin-disk laser allows for energy and power scaling with high efficiency. However the single pass gain is small (about 1.2). Hence a multi-pass scheme with precise mode matching for large beam waists (w = 2 mm) is required. Instead of using the standard 4f design, we have developed a multi-pass amplifier with a beam propagation insensitive to thermal lens effects and misalignments. The beam propagation is equivalent to multiple roundtrips in an optically stable resonator. To support the propagation we used an array of 2 x 8 individually adjustable plane mirrors. Astigmatism has been minimized by a compact mirror placement. Precise alignment of the kinematic arra...

  14. Complete genes may pass from food to human blood

    DEFF Research Database (Denmark)

    Spisák, Sándor; Solymosi, Norbert; Ittzés, Péter;

    2013-01-01

    Our bloodstream is considered to be an environment well separated from the outside world and the digestive tract. According to the standard paradigm large macromolecules consumed with food cannot pass directly to the circulatory system. During digestion proteins and DNA are thought to be degraded...

  15. 36 CFR 72.37 - Pass-through funding.

    Science.gov (United States)

    2010-07-01

    ... and Innovation § 72.37 Pass-through funding. Section 1006(a)(1) of the Act states that at the... Innovation grants may be transferred in whole or in part to independent special purpose local governments... which has provided other social services to the community, or a newly formed, but reliable and...

  16. Protocol-Based Verification of Message-Passing Parallel Programs

    DEFF Research Database (Denmark)

    López-Acosta, Hugo-Andrés; Eduardo R. B. Marques, Eduardo R. B.; Martins, Francisco;

    2015-01-01

    a protocol language based on a dependent type system for message-passing parallel programs, which includes various communication operators, such as point-to-point messages, broadcast, reduce, array scatter and gather. For the verification of a program against a given protocol, the protocol is first...

  17. An Analysis of Passing from the Psychological Perspective

    Institute of Scientific and Technical Information of China (English)

    马莲; 胡笑瑛

    2012-01-01

      The short novel Passing, written by Nella Larsen, who is an American novelist and short story writer. Larsen was best known for her contributions to the literary development in Harlem renaissance. This paper aims at analyzing the short novel from the psychological perspective.

  18. E.D.F. - Fish passes: follow up and efficiency

    International Nuclear Information System (INIS)

    After a brief recall on the steps of E.D.F. towards fish passes, this paper presents the different methods used for the control of fish passage facilities and the results obtained for structure conception or dimensioning. Informations on fish counting techniques, costs, efficiency and follow up of fish passage facilities are also given. 2 figs., 2 tabs., 8 photos

  19. Turbulent spots detection during boundary layer by-pass transition

    Czech Academy of Sciences Publication Activity Database

    Jonáš, Pavel; Elsner, W.; Mazur, Oton; Uruba, Václav; Wysocki, M.

    -, č. 80 (2009), s. 16-19. ISSN N R&D Projects: GA AV ČR(CZ) IAA200760614; GA MŠk MEB050810 Institutional research plan: CEZ:AV0Z20760514 Keywords : turbulent spot * boundary layer * by-pass transition * turbulent spot detection Subject RIV: BK - Fluid Dynamics

  20. 20 CFR 416.2096 - Basic pass-along rules.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Basic pass-along rules. 416.2096 Section 416.2096 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED State Supplementation Provisions; Agreement; Payments § 416.2096 Basic...

  1. Historical events: Single pass reactors and fuels fabrication

    Energy Technology Data Exchange (ETDEWEB)

    DeNeal, D.L.

    1970-04-10

    The intent of this report is to record, in one place, the significant historical events associated with the Single Pass Reactors from initial startup through December 1969. Significant events are chronologically listed in Section 1 and specific programs are summarized in Section 2.

  2. "Pass to Play" Legislation in California: Vegetables before Dessert!

    Science.gov (United States)

    Slater, Jana Kay

    1988-01-01

    The impact of legislation in California establishing "Pass to Play" policies of minimum academic requirements for extracurricular and co-curricular activities in grades 7 through 12 was examined. District policies varied widely and most were more stringent than required by legislation. Overall, the legislation helped establish academics as a…

  3. Wind profiles in Moscow city by the sodar data

    International Nuclear Information System (INIS)

    The results of wind measurements in the low 500 m air layer above Moscow by Doppler sodar 'MODOS' have been presented for period from 2004 to 2008. General features of both annual course and the diurnal one of wind profiles have been discussed. The most wind speed values are observed in average in autumn and in winter, the least ones - in spring and in summer. The most frequent wind direction is south-western; the rarest one is northern. The crossover height of wind profiles has been analyzed. As it was found it consists of 60-80 m in average in warm period. For the first time, mean values of wind turning during passing of atmospheric fronts have been received and studied by sodar data. It was found that right-hand (clockwise) turning of wind at cold fronts is more and occurs more quickly in time in the comparison with warm fronts. The occlusion fronts demonstrate intermediate mean values of wind turning

  4. In the wind of change. The wind power as pacesetters and guide to a fast turn to renewable energies; Im Wind des Wandels. Die Windkraft als Schrittmacher und Wegweiser zu einer schnellen Wende zu Erneuerbaren Energien

    Energy Technology Data Exchange (ETDEWEB)

    Scheer, H.; Alt, F.

    2007-07-01

    All renewable energy potentials (water power, bioenergy, wave power, geothermal energy) clearly are widespread as oil, natural gas, coal or uranium. For these potentials there are natural, spatial restrictions. In contrast to this, there exist any spatial restrictions for solar power and wind force. Under this aspect, the author of the contribution under consideration reports on wind force as a pacesetter and guide to a fast turn to renewable energy. Solar energy and wind energy have two crucial advantages of realizations: (a) The solar power plants and wind power plants can be installed faster than all other plants for generation of electrical power; (b) Solar power plants and wind power plants enable a radical shortening and simplification for the power supply. The generation and supply of electricity from solar power and wind power are also economically undefeatable. It is not a utopia to increase the contribution of the wind energy at the German power generation on basis of the renewable energy law in few years on over 40 %. The thesis, a further development of the wind power only is possible with offshore installations, because no suitable locations are present in the inland, is not correct. The emphasis of the use of wind power must remain with onshore plants. A broad dispersion of wind power plants should have priority, because the grid entrance is more easily realizable. The political attention must be directed toward the overcoming of the permission obstacles. Wind energy enables the passing of electricity from the shade of atomic and fossil power supply.

  5. LES investigation of infinite staggered wind-turbine arrays

    International Nuclear Information System (INIS)

    The layouts of turbines affect the turbine wake interactions and thus the wind farm performance. The wake interactions in infinite staggered wind-turbine arrays are investigated and compared with infinite aligned turbine arrays in this paper. From the numerical results we identify three types of wake behaviours, which are significantly different from wakes in aligned wind-turbine arrays. For the first type, each turbine wake interferes with the pair of staggered downstream turbine wakes and the aligned downstream turbine. For the second type, each turbine wake interacts with the first two downstream turbine wakes but does not show significant interference with the second aligned downstream turbine. For the third type, each turbine wake recovers immediately after passing through the gap of the first two downstream turbines and has little interaction with the second downstream turbine wakes The extracted power density and power efficiency are also studied and compared with aligned wind-turbine arrays

  6. LES investigation of infinite staggered wind-turbine arrays

    Science.gov (United States)

    Yang, Xiaolei; Sotiropoulos, Fotis

    2014-12-01

    The layouts of turbines affect the turbine wake interactions and thus the wind farm performance. The wake interactions in infinite staggered wind-turbine arrays are investigated and compared with infinite aligned turbine arrays in this paper. From the numerical results we identify three types of wake behaviours, which are significantly different from wakes in aligned wind-turbine arrays. For the first type, each turbine wake interferes with the pair of staggered downstream turbine wakes and the aligned downstream turbine. For the second type, each turbine wake interacts with the first two downstream turbine wakes but does not show significant interference with the second aligned downstream turbine. For the third type, each turbine wake recovers immediately after passing through the gap of the first two downstream turbines and has little interaction with the second downstream turbine wakes The extracted power density and power efficiency are also studied and compared with aligned wind-turbine arrays.

  7. 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.

  8. Wind electric power generation

    International Nuclear Information System (INIS)

    The monthly statistics of wind electric power generation in Denmark are compiled from information given by the owners of 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 1988 and 1989. Also the data of operation start are given. On the map of Denmark the sites of the wind turbines are marked. The statistics for December 1994 comprise 2328 wind turbines

  9. Wind energy; Energia eolica

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Marcus Vinicius Gusmao do; Lima, Jorge H. Greco; Francescutti, Fabio Gino; Dutra, Ricardo Marques; Silva, Patricia de Castro; Giannini, Marcio; Vianna Junior, Affonso [Centro de Pesquisa de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)

    2003-07-01

    This chapter gives an overview on energy generation from wind energy, presenting a panoramic approaching on the state-of-art of wind energy, the evolution of the technological dynamics of the sector in Brazil, description of the wind energy technology, the environment and the wind energy, analysis of the economic viability, the strategy for the development of a Brazilian wind energy technology, the estimative for the necessary financial resources, the identification of the present barriers to the penetration of the technology, the mechanisms for the viabilization of the technology introduction.

  10. Wind Power Outlook 2004

    Energy Technology Data Exchange (ETDEWEB)

    anon.

    2004-01-01

    The brochure, expected to be updated annually, provides the American Wind Energy Association's (AWAE's) up-to-date assessment of the wind industry. It provides a summary of the state of wind power in the U.S., including the challenges and opportunities facing the industry. It provides summary information on the growth of the industry, policy-related factors such as the federal wind energy production tax credit status, comparisons with natural gas, and public views on wind energy.

  11. 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...

  12. Wind energy information directory

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-10-01

    Wind Energy Information has been prepared to provide researchers, designers, manufacturers, distributors, dealers, and users of wind energy conversion systems with easy access to technical information. This directory lists organizations and publications which have the main objective of promoting the use of wind energy conversion systems, some organizations that can respond to requests for information on wind energy or make referrals to other sources of information, and some publications that occasionally include information on wind energy. The bibliography contains references to information for both the neophyte and the expert.

  13. Wind Turbine Structural Dynamics

    Science.gov (United States)

    Miller, D. R. (Editor)

    1978-01-01

    A workshop on wind turbine structural dynamics was held to review and document current United States work on the dynamic behavior of large wind turbines, primarily of the horizontal-axis type, and to identify and discuss other wind turbine configurations that may have lower cost and weight. Information was exchanged on the following topics: (1) Methods for calculating dynamic loads; (2) Aeroelasticity stability (3) Wind loads, both steady and transient; (4) Critical design conditions; (5) Drive train dynamics; and (6) Behavior of operating wind turbines.

  14. 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...

  15. Wind energy in Europe

    International Nuclear Information System (INIS)

    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

  16. Piezoelectric wind turbine

    Science.gov (United States)

    Kishore, Ravi Anant; Priya, Shashank

    2013-03-01

    In past few years, there has been significant focus towards developing small scale renewable energy based power sources for powering wireless sensor nodes in remote locations such as highways and bridges to conduct continuous health monitoring. These prior efforts have led to the development of micro-scale solar modules, hydrogen fuel cells and various vibration based energy harvesters. However, the cost effectiveness, reliability, and practicality of these solutions remain a concern. Harvesting the wind energy using micro-to-small scale wind turbines can be an excellent solution in variety of outdoor scenarios provided they can operate at few miles per hour of wind speed. The conventional electromagnetic generator used in the wind mills always has some cogging torque which restricts their operation above certain cut-in wind speed. This study aims to develop a novel piezoelectric wind turbine that utilizes bimorph actuators for electro-mechanical energy conversion. This device utilizes a Savonius rotor that is connected to a disk having magnets at the periphery. The piezoelectric actuators arranged circumferentially around the disk also have magnets at the tip which interacts with the magnetic field of the rotating disk and produces cyclical deflection. The wind tunnel experiments were conducted between 2-12 mph of wind speeds to characterize and optimize the power output of the wind turbine. Further, testing was conducted in the open environment to quantify the response to random wind gusts. An attempt was made towards integration of the piezoelectric wind turbine with the wireless sensor node.

  17. The aeolian wind tunnel

    Science.gov (United States)

    Iversen, J. D.

    1991-01-01

    The aeolian wind tunnel is a special case of a larger subset of the wind tunnel family which is designed to simulate the atmospheric surface layer winds to small scale (a member of this larger subset is usually called an atmospheric boundary layer wind tunnel or environmental wind tunnel). The atmospheric boundary layer wind tunnel is designed to simulate, as closely as possible, the mean velocity and turbulence that occur naturally in the atmospheric boundary layer (defined as the lowest portion of the atmosphere, of the order of 500 m, in which the winds are most greatly affected by surface roughness and topography). The aeolian wind tunnel is used for two purposes: to simulate the physics of the saltation process and to model at small scale the erosional and depositional processes associated with topographic surface features. For purposes of studying aeolian effects on the surface of Mars and Venus as well as on Earth, the aeolian wind tunnel continues to prove to be a useful tool for estimating wind speeds necessary to move small particles on the three planets as well as to determine the effects of topography on the evolution of aeolian features such as wind streaks and dune patterns.

  18. Offshore Wind Power Data

    DEFF Research Database (Denmark)

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

    2012-01-01

    – 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...... this work was to create a dataset containing forecast and realised wind power time series with hourly resolution. The database should cover all Europe, i.e. onshore and offshore and it will be further used in the project for the economic assessment impact, Tasks 16.2.2 and 16.2.3. For the onshore wind...

  19. Estonian wind climate

    International Nuclear Information System (INIS)

    Estonia is situated on the eastern coast of the Baltic Sea. This is a region with intensive cyclonic activity and therefore with a relatively high mean wind speed. Atmospheric circulation and its seasonal variation determine the general character of the Estonian wind regime over the Atlantic Ocean and Eurasia. However, the Baltic sea itself is a very important factor affecting wind climate, it has an especially strong influence on the wind regime in costal areas. The mean energy density (W/m2) is a wind energy characteristic that is proportional to the third power of wind speed and describes energy available in a flow of air through a unit area. The mean energy density is a characteristic which has practical importance in regional assessment of snowdrift, storm damage and wind energy

  20. 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.

  1. 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.

  2. Wind power takes over

    International Nuclear Information System (INIS)

    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

  3. Statistics of Epidemics in Networks by Passing Messages

    Science.gov (United States)

    Shrestha, Munik Kumar

    Epidemic processes are common out-of-equilibrium phenomena of broad interdisciplinary interest. In this thesis, we show how message-passing approach can be a helpful tool for simulating epidemic models in disordered medium like networks, and in particular for estimating the probability that a given node will become infectious at a particular time. The sort of dynamics we consider are stochastic, where randomness can arise from the stochastic events or from the randomness of network structures. As in belief propagation, variables or messages in message-passing approach are defined on the directed edges of a network. However, unlike belief propagation, where the posterior distributions are updated according to Bayes' rule, in message-passing approach we write differential equations for the messages over time. It takes correlations between neighboring nodes into account while preventing causal signals from backtracking to their immediate source, and thus avoids "echo chamber effects" where a pair of adjacent nodes each amplify the probability that the other is infectious. In our first results, we develop a message-passing approach to threshold models of behavior popular in sociology. These are models, first proposed by Granovetter, where individuals have to hear about a trend or behavior from some number of neighbors before adopting it themselves. In thermodynamic limit of large random networks, we provide an exact analytic scheme while calculating the time dependence of the probabilities and thus learning about the whole dynamics of bootstrap percolation, which is a simple model known in statistical physics for exhibiting discontinuous phase transition. As an application, we apply a similar model to financial networks, studying when bankruptcies spread due to the sudden devaluation of shared assets in overlapping portfolios. We predict that although diversification may be good for individual institutions, it can create dangerous systemic effects, and as a result

  4. Behavior of bats at wind turbines.

    Science.gov (United States)

    Cryan, Paul M; Gorresen, P Marcos; Hein, Cris D; Schirmacher, Michael R; Diehl, Robert H; Huso, Manuela M; Hayman, David T S; Fricker, Paul D; Bonaccorso, Frank J; Johnson, Douglas H; Heist, Kevin; Dalton, David C

    2014-10-21

    Wind turbines are causing unprecedented numbers of bat fatalities. Many fatalities involve tree-roosting bats, but reasons for this higher susceptibility remain unknown. To better understand behaviors associated with risk, we monitored bats at three experimentally manipulated wind turbines in Indiana, United States, from July 29 to October 1, 2012, using thermal cameras and other methods. We observed bats on 993 occasions and saw many behaviors, including close approaches, flight loops and dives, hovering, and chases. Most bats altered course toward turbines during observation. Based on these new observations, we tested the hypotheses that wind speed and blade rotation speed influenced the way that bats interacted with turbines. We found that bats were detected more frequently at lower wind speeds and typically approached turbines on the leeward (downwind) side. The proportion of leeward approaches increased with wind speed when blades were prevented from turning, yet decreased when blades could turn. Bats were observed more frequently at turbines on moonlit nights. Taken together, these observations suggest that bats may orient toward turbines by sensing air currents and using vision, and that air turbulence caused by fast-moving blades creates conditions that are less attractive to bats passing in close proximity. Tree bats may respond to streams of air flowing downwind from trees at night while searching for roosts, conspecifics, and nocturnal insect prey that could accumulate in such flows. Fatalities of tree bats at turbines may be the consequence of behaviors that evolved to provide selective advantages when elicited by tall trees, but are now maladaptive when elicited by wind turbines. PMID:25267628

  5. Behavior of bats at wind turbines

    Science.gov (United States)

    Cryan, Paul M.; Gorresen, P. Marcos; Hine, Cris D.; Schirmacher, Michael; Diehl, Robert H.; Huso, Manuela M.; Hayman, David T.S.; Fricker, Paul D.; Bonaccorso, Frank J.; Johnson, Douglas H.; Heist, Kevin W.; Dalton, David C.

    2014-01-01

    Wind turbines are causing unprecedented numbers of bat fatalities. Many fatalities involve tree-roosting bats, but reasons for this higher susceptibility remain unknown. To better understand behaviors associated with risk, we monitored bats at three experimentally manipulated wind turbines in Indiana, United States, from July 29 to October 1, 2012, using thermal cameras and other methods. We observed bats on 993 occasions and saw many behaviors, including close approaches, flight loops and dives, hovering, and chases. Most bats altered course toward turbines during observation. Based on these new observations, we tested the hypotheses that wind speed and blade rotation speed influenced the way that bats interacted with turbines. We found that bats were detected more frequently at lower wind speeds and typically approached turbines on the leeward (downwind) side. The proportion of leeward approaches increased with wind speed when blades were prevented from turning, yet decreased when blades could turn. Bats were observed more frequently at turbines on moonlit nights. Taken together, these observations suggest that bats may orient toward turbines by sensing air currents and using vision, and that air turbulence caused by fast-moving blades creates conditions that are less attractive to bats passing in close proximity. Tree bats may respond to streams of air flowing downwind from trees at night while searching for roosts, conspecifics, and nocturnal insect prey that could accumulate in such flows. Fatalities of tree bats at turbines may be the consequence of behaviors that evolved to provide selective advantages when elicited by tall trees, but are now maladaptive when elicited by wind turbines.

  6. Effect of Wind Direction on ENVISAT ASAR Wind Speed Retrieval

    DEFF Research Database (Denmark)

    Takeyama, Yuko; Ohsawa, Teruo; Kozai, Katsutoshi;

    2010-01-01

    results, the WRF wind direction retrieves sea surface wind speeds with higher accuracies of the other wind directions at Hiratsuka. On the other hand, at Shirahama, it is not found an advantage of the WRF wind direction. Thus, the WRF wind direction cannot always retrieve wind speed with a high accuracy......This paper presents an evaluation of effects of wind directions (NCEP, MANAL, QuickSCAT and WRF) on the sea surface wind speed retrieval from 75 ENVISAT ASAR images with four C-band Geophysical model functions, CMOD4, CMOD_IFR2, CMOD5 and CMOD5N at two target areas, Hiratsuka and Shirahama. As....... However, a wind speed error generated with the WRF wind direction is the smallest of those with the other wind directions, and the error is as small as the level of SAR original radiometric errors. Consequently, the WRF wind direction is the most suitable of the four wind directions on the SAR wind speed...

  7. Wind power certificate marketing

    International Nuclear Information System (INIS)

    Wind Power Certificate marketing is a green power development program in Canada. The Pembina Institute partnered with Vision Quest Windelectric in October 2003 to sell Wind Power Certificates to individuals and businesses. Individuals who buy Wind Power Certificates directly support the development of wind energy in Canada and support one of Pembina's main areas of work, the development of sustainable energy. This presentation outlined both the successes and challenges of marketing the certificates. Wind Power Certificates represent the benefits that wind power generation provides, such as zero emissions of greenhouse gases and regional air pollutants; minimal impacts on the biosphere; and, offsetting life-cycle impacts of other energy sources such as fossil fuels. They also represent quality assurance on new wind power commissioned after April 2001. In the price structure of Pembina's Wind Power Certificate, a premium of 2.7 cents per kWh is charged above the regular electricity price. The premium is lowered slightly for purchases of 200 MWh or more. Pembina also began a secondary campaign in July 2004 to have 20,000 computers powered by wind across Canada. This PC campaign offers the general public an option to support wind power development in a way that is easy to understand. In the PC campaign, a consumer is asked to pay $16 per 3 years for a laptop computer or $32 per 3 years for an average desktop computer. Vision Quest has received a Market Incentive Program grant through Natural Resources Canada to help market Pembina's wind power programs. Although the programs are too new to provide important statistical information, some small successes have been reported to date including 1950 MWh of Wind Power Certificates that have been purchased, representing a reduction of about 1730 tonnes of carbon dioxide. One of the challenges facing the Wind Power Certificate program is that some companies feel they already pay too much for electricity and the premium cost of

  8. Second wind in the offshore wind industry

    International Nuclear Information System (INIS)

    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

  9. Terrain-influenced local wind forecasting for the Sasebo typhoon haven: Improved empirical techniques

    Science.gov (United States)

    Feldmeier, Joel W.; Nuss, Wendell A.; Elsberry, Russell L.

    2014-08-01

    Although the Sasebo, Japan harbor is usually a "typhoon haven" from tropical cyclone (TC) winds due to terrain-blocking effects, in rare cases damaging winds occur that may be attributed to terrain channeling. An empirical parametric model technique is developed and tested that includes consideration of the TC wind structure, land frictional effects, and terrain influences affecting the maximum wind speeds in the harbor when TCs pass within 200 nautical miles of Sasebo. The terrain influence is represented by two sets of wind direction-dependent acceleration factors. The first set, which is directly from the ratio of the local wind to the adjusted parametric wind for TCs passages during 2003-2010, provides mean values that represent the terrain blocking and channeling effects, but the variability with wind direction may be suspect. The second set derived from a large sample of reanalysis winds not limited to TCs has better variability properties, but is not easily related to just the TC passages. A new nomogram modified to include TC wind structure has higher estimates of Sasebo sustained winds for some TC tracks that may be related to terrain influences, but is limited due to the number of TC structure estimates in the developmental sample. These empirical models have the advantage of ease and low cost for future use in also estimating the combined uncertainty in the local winds in Sasebo harbor due to TCs.

  10. Finite element simulation of sink pass round tubes using Ansys

    Directory of Open Access Journals (Sweden)

    Nagarkar M.P.

    2012-01-01

    Full Text Available Modeling and simulation of metal forming processes are increasingly in demand from the industry as the resulting models are found to be valuable tools considering the optimization of the existing and development of new processes. By the application of modeling and simulation techniques, it is possible to reduce the number of time-consuming experiments such as prototyping. Seamless tubes of various sizes and shapes are manufactured by various processes like sinking, fixed plug, floating plug, moving mandrel, cold working and hot working. The present work deals with the simulation of round tubes while passing through the sink pass, using ANSYS software. The simulation results are the displacement and von Mises stresses. The procedure can be used to improve the product quality and to study the effect of various parameters like die angle on the product quality.

  11. PASS Syndrome: An IL-1-Driven Autoinflammatory Disease.

    Science.gov (United States)

    Leuenberger, Mathieu; Berner, Jeanne; Di Lucca, Julie; Fischer, Lara; Kaparos, Nikolaos; Conrad, Curdin; Hohl, Daniel; So, Alexander; Gilliet, Michel

    2016-01-01

    PASS syndrome is a rare inflammatory disease characterized by a chronic-relapsing course of pyoderma gangrenosum, acne vulgaris, hidradenitis suppurativa and ankylosing spondylitis. Here, we describe a case of a patient with spontaneously recurrent purulent skin lesions along with seronegative spondylarthritis consistent with the PASS syndrome. During his disease exacerbation, the patient displayed episodes of fever along with elevated serum levels of interleukin (IL)-1β. Skin lesions were characterized by sterile neutrophilic infiltrates and showed a rapid response to the IL-1 receptor antagonist anakinra (Kineret®) consistent with the autoinflammatory nature of this disease. However, unlike other autoinflammatory diseases such as PAPA and PAPASH, we did not find mutations in the gene PSTPIP1, raising the possibility that other specific mutations in the IL-1 pathway may be involved. PMID:26919742

  12. Optically tunable acoustic wave band-pass filter

    Directory of Open Access Journals (Sweden)

    N. Swinteck

    2014-12-01

    Full Text Available The acoustic properties of a hybrid composite that exhibits both photonic and phononic behavior are investigated numerically with finite-element and finite-difference time-domain simulations. The structure is constituted of a periodic array of photonic resonant cavities embedded in a background superlattice. The resonant cavities contain a photo-elastic chalcogenide glass that undergoes atomic-scale structural reorganization when irradiated with light having energy close to its band-gap. Photo-excitation of the chalcogenide glass changes its elastic properties and, consequently, augments the acoustic transmission spectrum of the composite. By modulating the intensity of light irradiating the hybrid photonic/phononic structure, the position and spectral width of phonon passing-bands can be controlled. This demonstration offers the technological platform for optically-tunable acoustic wave band-pass filters.

  13. FIRST PASS APPLICATION TO TURKEY FINANCIAL REPORTING STANDARDS FOR SMEs

    Directory of Open Access Journals (Sweden)

    Murat ERDOĞAN

    2014-06-01

    Full Text Available First pass application to Turkey financial reporting standards for SMEs is aimed to explain financial reporting style and conditions that is applied by companies and give informations to companies by using sample application with publication of International Financial Reporting Standards on 9th July 2009 and publication IFRS for SMEs on 1th November 2010 and in the 27746 Number Official News by Public Oversight, Accounting and Auditing Standards Authority in Turkey. The financial statements of a hotel with the nature of SME that trades in Turkey, doesn’t have any liabilities of public accountability, doesn’t publish any financial statements for external users have been reordered according to IFRS for SMEs and first-pass application to these standards has been studied in the third and last part of the study.

  14. Flow Analysis in Two Pass Smooth Square Channel

    Directory of Open Access Journals (Sweden)

    R.T.SARATH BABU

    2014-08-01

    Full Text Available This project aim is to presenting the air flow analysis in two pass smooth square channel experiments. The experiments were carried out on a horizontally oriented two pass smooth square channel with turn in sharp 1800 . The smooth square channel size was 2 cm. Calculations were performed by using CFD software “gambit &fluent”. The predictions results of mass flow rate & heat transfer rate of the air flow inside the sharp 180° turn in square channel with using different Reynolds numbers (10000, 20000, 40000 & 60000 were compared against with experiment results obtained from based on journal. Computational fluid dynamics simulations were performed using Gambit2.3.16&Fluent6.3.26 software with 2D, unsteady and turbulent flow conditions assumed. Three different turbulence models were used namely the k-ε, k  and Reynolds stress models in conjunction with non-equilibrium wall functions.

  15. Location constrained approximate message passing for compressed sensing MRI.

    Science.gov (United States)

    Sung, Kyunghyun; Daniel, Bruce L; Hargreaves, Brian A

    2013-08-01

    Iterative thresholding methods have been extensively studied as faster alternatives to convex optimization methods for solving large-sized problems in compressed sensing. A novel iterative thresholding method called LCAMP (Location Constrained Approximate Message Passing) is presented for reducing computational complexity and improving reconstruction accuracy when a nonzero location (or sparse support) constraint can be obtained from view shared images. LCAMP modifies the existing approximate message passing algorithm by replacing the thresholding stage with a location constraint, which avoids adjusting regularization parameters or thresholding levels. This work is first compared with other conventional reconstruction methods using random one-dimention signals and then applied to dynamic contrast-enhanced breast magnetic resonance imaging to demonstrate the excellent reconstruction accuracy (less than 2% absolute difference) and low computation time (5-10 s using Matlab) with highly undersampled three-dimentional data (244 × 128 × 48; overall reduction factor = 10). PMID:23042658

  16. Denoising Message Passing for X-ray Computed Tomography Reconstruction

    CERN Document Server

    Perelli, Alessandro; Can, Ali; Davies, Mike E

    2016-01-01

    X-ray Computed Tomography (CT) reconstruction from sparse number of views is becoming a powerful way to reduce either the radiation dose or the acquisition time in CT systems but still requires a huge computational time. This paper introduces an approximate Bayesian inference framework for CT reconstruction based on a family of denoising approximate message passing (DCT-AMP) algorithms able to improve both the convergence speed and the reconstruction quality. Approximate Message Passing for Compressed Sensing has been extensively analysed for random linear measurements but there are still not clear solutions on how AMP should be modified and how it performs with real world problems. In particular to overcome the convergence issues of DCT-AMP with structured measurement matrices, we propose a disjoint preconditioned version of the algorithm tailored for both the geometric system model and the noise model. In addition the Bayesian DCT-AMP formulation allows to measure how the current estimate is close to the pr...

  17. A Dynamic Continuation-Passing Style for Dynamic Delimited Continuations

    DEFF Research Database (Denmark)

    Biernacki, Dariusz; Danvy, Olivier; Millikin, Kevin Scott

    We present a new abstract machine that accounts for dynamic delimited continuations. We prove the correctness of this new abstract machine with respect to a pre-existing, definitional abstract machine. Unlike this definitional abstract machine, the new abstract machine is in defunctionalized form......, which makes it possible to state the corresponding higher-order evaluator. This evaluator is in continuation+state passing style and threads a trail of delimited continuations and a meta-continuation. Since this style accounts for dynamic delimited continuations, we refer to it as `dynamic continuation......-passing style.' We show that the new machine operates more efficiently than the definitional one and that the notion of computation induced by the corresponding evaluator takes the form of a monad. We also present new examples and a new simulation of dynamic delimited continuations in terms of static ones....

  18. Testing the Turing Test — do Men Pass It?

    Science.gov (United States)

    Adam, Ruth; Hershberg, Uri; Schul, Yaacov; Solomon, Sorin

    We are fascinated by the idea of giving life to the inanimate. The fields of Artificial Life and Artificial Intelligence (AI) attempt to use a scientific approach to pursue this desire. The first steps on this approach hark back to Turing and his suggestion of an imitation game as an alternative answer to the question "can machines think?".1 To test his hypothesis, Turing formulated the Turing test1 to detect human behavior in computers. But how do humans pass such a test? What would you say if you would learn that they do not pass it well? What would it mean for our understanding of human behavior? What would it mean for our design of tests of the success of artificial life? We report below an experiment in which men consistently failed the Turing test.

  19. Fault Tolerant Wind Farm Control

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2013-01-01

    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 scenarios. This benchmark model is used in an international competition dealing with Wind Farm fault detection and isolation and fault tolerant control....

  20. Fish pass assessment by remote control: a novel framework for quantifying the hydraulics at fish pass entrances

    Science.gov (United States)

    Kriechbaumer, Thomas; Blackburn, Kim; Gill, Andrew; Breckon, Toby; Everard, Nick; Wright, Ros; Rivas Casado, Monica

    2014-05-01

    Fragmentation of aquatic habitats can lead to the extinction of migratory fish species with severe negative consequences at the ecosystem level and thus opposes the target of good ecological status of rivers defined in the EU Water Framework Directive (WFD). In the UK, the implementation of the EU WFD requires investments in fish pass facilities of estimated 532 million GBP (i.e. 639 million Euros) until 2027 to ensure fish passage at around 3,000 barriers considered critical. Hundreds of passes have been installed in the past. However, monitoring studies of fish passes around the world indicate that on average less than half of the fish attempting to pass such facilities are actually successful. There is a need for frameworks that allow the rapid identification of facilities that are biologically effective and those that require enhancement. Although there are many environmental characteristics that can affect fish passage success, past research suggests that variations in hydrodynamic conditions, reflected in water velocities, velocity gradients and turbulences, are the major cues that fish use to seek migration pathways in rivers. This paper presents the first steps taken in the development of a framework for the rapid field-based quantification of the hydraulic conditions downstream of fish passes and the assessment of the attractivity of fish passes for salmonids and coarse fish in UK rivers. For this purpose, a small-sized remote control platform carrying an acoustic Doppler current profiler (ADCP), a GPS unit, a stereo camera and an inertial measurement unit has been developed. The large amount of data on water velocities and depths measured by the ADCP within relatively short time is used to quantify the spatial and temporal distribution of water velocities. By matching these hydraulic features with known preferences of migratory fish, it is attempted to identify likely migration routes and aggregation areas at barriers as well as hydraulic features that

  1. Exchange Rate Pass-through in a Small Open Economy

    OpenAIRE

    Boug, Pål; Cappelen, Ådne; Eika, Torbjørn

    2005-01-01

    Abstract: Several small open economies switched to inflation targeting during the 1990s, thereby giving up various forms of exchange rate targeting in favour of flexible exchange rates. Norway did the same early in 2001, and has thereafter experienced highly varying nominal exchange rates with consumer price inflation dropping far below the target during 2003 and 2004. Knowledge of the degree of exchange rate pass-through to import prices and further to consumer prices is essen...

  2. Citizen Monitoring Along Interstate 90 at Snoqualmie Pass

    OpenAIRE

    Watkins, Jen; Moskowitz, Dave

    2007-01-01

    Interstate 90 over the Cascades is significant barrier to over 250 species of wildlife, including cougar, elk, deer, mustelids (otters, fishers, badgers, etc.), amphibians and reptiles. In the vicinity of Snoqualmie Pass, urban development to the west and agriculture and resort development on the east has shrunk the forest connecting north and south Cascades to less than 64.6 kilometers wide. The Washington State Department of Transportation (WSDOT) is proposing to expand a 24.15-kil...

  3. A Message-Passing Model for Service Oriented Computing

    OpenAIRE

    Allam, Diana; Douence, Rémi; Grall, Hervé; Royer, Jean-Claude; Südholt, Mario

    2012-01-01

    Service-based applications can be built according to multiple technologies. Although there is a clear need for a model integrating them in multiple real-world contexts, no integrated model does (yet) exist. In this paper we introduce a model as a foundation for heterogeneous services, with particularly studying SOAP/WS* and RESTful models. The model completely abstracts away from service implementations, composes them in a truly concurrent manner, and supports asynchronous message passing as ...

  4. A SECURITY STRATEGY AGAINST STEAL-AND-PASS CREDENTIAL ATTACKS

    OpenAIRE

    Juan Ceballos

    2016-01-01

    Stealing and passing credentials is currently one of the preferred cyberattack techniques within the hacking community as shown by the increasing number of related incidents over the last years. Instead of targeting passwords, attackers focus on obtaining derived credentials like hashes and session tickets. This type of credentials facilitates taking advantage of omnipresent background mechanisms like Single Sign-On. A combination of malware and penetration tools is used in order to exploi...

  5. On the Complexity of Buffer Allocation in Message Passing Systems

    OpenAIRE

    Brodsky, Alex; Pedersen, Jan B.; Wagner, Alan

    2003-01-01

    Message passing programs commonly use buffers to avoid unnecessary synchronizations and to improve performance by overlapping communication with computation. Unfortunately, using buffers makes the program no longer portable, potentially unable to complete on systems without a sufficient number of buffers. Effective buffer use entails that the minimum number needed for a safe execution be allocated. We explore a variety of problems related to buffer allocation for safe and efficient execution ...

  6. NEAR-MILLIMETER WAVE BAND-PASS FILTERS

    Energy Technology Data Exchange (ETDEWEB)

    Timusk, T.; Richards, P. L.

    1980-11-01

    We report on the properties of band-pass filters for broad band photometry in the frequency range from 3 to 12cm{sup -1}. The filters are based on a combination of capacitive grids deposited on thick Mylar substrates and are designed to have very high out-of-band rejection. Low frequencies are blocked by a "thick grill" that consists of hexagonal grid of circular holes in a thick metal plate.

  7. Thermal efficiency of single-pass solar air collector

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, Zamry; Ibarahim, Zahari; Yatim, Baharudin [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan (Malaysia); Ruslan, Mohd Hafidz [Solar Energy Research Institute (SERI), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor Darul Ehsan (Malaysia)

    2013-11-27

    Efficiency of a finned single-pass solar air collector was studied. This paper presents the experimental study to investigate the effect of solar radiation and mass flow rate on efficiency. The fins attached at the back of absorbing plate to improve the thermal efficiency of the system. The results show that the efficiency is increased proportional to solar radiation and mass flow rate. Efficiency of the collector archived steady state when reach to certain value or can be said the maximum performance.

  8. Generalized Coupled-line All-Pass Phasers

    OpenAIRE

    Gupta, S.; Zhang, Q.; ZOU, L.; Jiang, L.; Caloz, C.

    2014-01-01

    Generalized coupled-line all-pass phasers, based on transversally-cascaded (TC), longitudinally-cascaded (LC) and hybrid-cascaded (HC) coupled transmission line sections, are presented and demonstrated using analytical, full-wave and experimental results. It is shown that for N commensurate coupled-line sections, LC and TC phasers exhibit N group delay peaks per coupled-line section harmonic frequency band, in contrast to the TC configuration, which exhibits only one peak within this band. It...

  9. Interest Rate Pass-through in Sri Lanka

    OpenAIRE

    Amarasekara, Chandranath

    2005-01-01

    The Central Bank of Sri Lanka has increasingly been relying on interest rates as the instrument for conducting monetary policy. Changes to the key monetary policy variables, the Repo and the Reverse Repo rates, are initially expected to be reflected in the OMO rates and the call money market rates, before being passedthrough to commercial bank retail interest rates. It is important to obtain a good understanding of the speed and magnitude of the interest rate pass-through to make timely monet...

  10. Pass-Through in United States Beef Cattle Prices

    OpenAIRE

    Huan Zhao; Xiaodong Du; Hennessy, David A.

    2009-01-01

    Feeder cattle are fattened to become fed live cattle six months later. The U.S. feeder cattle industry is intensively competitive, so that market efficiency suggests feeder cattle prices should fully reflect feed prices and information on future fed cattle prices. Employing a long time series (1979-2004) of feeder cattle futures, live cattle futures, and local corn prices, we test whether complete pass-through occurs. The results indicate that an increase of a dollar per hundred pounds in the...

  11. Interval-Passing Algorithm for Chemical Mixture Estimation

    OpenAIRE

    Danjean, Ludovic; Vasic, Bane; Marcellin, Michael; Declercq, David

    2013-01-01

    International audience In this letter we propose a compressive sensing scheme for the mixture estimation problem in spectroscopy. We show that by applying an appropriate measurement matrix on the chemical mixture spectrum, we obtain an overall measurement matrix which is sparse. This enables the use of a low-complexity iterative reconstruction algorithm, called the interval-passing algorithm, to estimate the concentration of each chemical present in the mixture. Simulation results for the ...

  12. Radiation of ultrarelativistic particles passing through ideal and mosaic crystals

    International Nuclear Information System (INIS)

    When a charged particle passes through an ideal crystal, then besides the transition radiation, a new kind of radiation, connected with the periodic structure of the crystal is produced. The influence of mosaic structure of a crystal on the intensity of this radiation is considered. Simple analytical expressions for the integral intensity of this radiation for the case of an ideal crystal are obtained. The results show, that the integral radiation intensity depends weakly on the degree of crystal perfection

  13. One pass learning for generalized classifier neural network.

    Science.gov (United States)

    Ozyildirim, Buse Melis; Avci, Mutlu

    2016-01-01

    Generalized classifier neural network introduced as a kind of radial basis function neural network, uses gradient descent based optimized smoothing parameter value to provide efficient classification. However, optimization consumes quite a long time and may cause a drawback. In this work, one pass learning for generalized classifier neural network is proposed to overcome this disadvantage. Proposed method utilizes standard deviation of each class to calculate corresponding smoothing parameter. Since different datasets may have different standard deviations and data distributions, proposed method tries to handle these differences by defining two functions for smoothing parameter calculation. Thresholding is applied to determine which function will be used. One of these functions is defined for datasets having different range of values. It provides balanced smoothing parameters for these datasets through logarithmic function and changing the operation range to lower boundary. On the other hand, the other function calculates smoothing parameter value for classes having standard deviation smaller than the threshold value. Proposed method is tested on 14 datasets and performance of one pass learning generalized classifier neural network is compared with that of probabilistic neural network, radial basis function neural network, extreme learning machines, and standard and logarithmic learning generalized classifier neural network in MATLAB environment. One pass learning generalized classifier neural network provides more than a thousand times faster classification than standard and logarithmic generalized classifier neural network. Due to its classification accuracy and speed, one pass generalized classifier neural network can be considered as an efficient alternative to probabilistic neural network. Test results show that proposed method overcomes computational drawback of generalized classifier neural network and may increase the classification performance. PMID

  14. Family networks and material inheritances: passing on the testimony

    Directory of Open Access Journals (Sweden)

    Marta Faria Patrão

    2012-11-01

    Full Text Available This study aims to deepen the knowledge about the process of material inheritance transmission in later life families, by studying the profiles of transmission of material legacy (what is transmitted, to whom, when and how?, the dynamics of support between donors and heirs and their influence on family satisfaction. Main results suggest that material inheritance is a normative process in later life families, involving the reorganization of the management of families’ material property and its transmission (passing on financial testimony.

  15. Switched Band-Pass Filters for Adaptive Transceivers

    Science.gov (United States)

    Wang, Ray

    2007-01-01

    Switched band-pass filters are key components of proposed adaptive, software- defined radio transceivers that would be parts of envisioned digital-data-communication networks that would enable real-time acquisition and monitoring of data from geographically distributed sensors. Examples of sensors to be connected to such networks include security cameras, radio-frequency identification units, and geolocation units based on the Global Positioning System. Through suitable software configuration and without changing hardware, these transceivers could be made to operate according to any of a number of complex wireless-communication standards that could be characterized by diverse modulation schemes, bandwidths, and data-handling protocols. The adaptive transceivers would include field-programmable gate arrays (FPGAs) and digital signal-processing hardware. In the receiving path of a transceiver, the incoming signal would be amplified by a low-noise amplifier (LNA). The output spectrum of the LNA would be processed by a band-pass filter operating in the frequency range between 900 MHz and 2.4 GHz. Then a down-converter would translate the signal to a lower frequency range to facilitate analog-to-digital conversion, which would be followed by baseband processing by one or more FPGAs. In the transmitting path, a digital stream would first be converted to an analog signal, which would then be up-converted to a selected frequency band before being applied to a transmitting power amplifier. The aforementioned band-pass filter in the receiving path would be a combination of resonant inductor-and-capacitor filters and switched band-pass filters. The overall combination would implement a switch function designed mathematically to exhibit desired frequency responses and to switch the signal in each frequency band to an analog-to-digital converter appropriate for that band to produce a digital intermediate-frequency signal for digital signal processing.

  16. Petrological and geochemical investigations at the Cajon Pass Deep Drillhole

    OpenAIRE

    Silver, Leon T.; James, Eric W.; Chappell, Bruce W.

    1988-01-01

    Chemical analyses of cores from the Cajon Pass Deep Drillhole confirm vertical lithologic diversity of the basement rocks. They are metaluminous and calcalkaline; weak major element correlations with wide-ranging SiO_2 suggest they are not a simple cogenetic suite. Quartz contents correlate with the thermal gradient profile, supporting conduction as the principal thermal transport mechanism. Abundances of heat producing elements are variable and somewhat lower than average crustal values. Cro...

  17. Verification-Based Interval-Passing Algorithm for Compressed Sensing

    OpenAIRE

    Wu, Xiaofu; Yang, Zhen

    2013-01-01

    We propose a verification-based Interval-Passing (IP) algorithm for iteratively reconstruction of nonnegative sparse signals using parity check matrices of low-density parity check (LDPC) codes as measurement matrices. The proposed algorithm can be considered as an improved IP algorithm by further incorporation of the mechanism of verification algorithm. It is proved that the proposed algorithm performs always better than either the IP algorithm or the verification algorithm. Simulation resul...

  18. Direct message passing for hybrid Bayesian networks and performance analysis

    Science.gov (United States)

    Sun, Wei; Chang, K. C.

    2010-04-01

    Probabilistic inference for hybrid Bayesian networks, which involves both discrete and continuous variables, has been an important research topic over the recent years. This is not only because a number of efficient inference algorithms have been developed and used maturely for simple types of networks such as pure discrete model, but also for the practical needs that continuous variables are inevitable in modeling complex systems. Pearl's message passing algorithm provides a simple framework to compute posterior distribution by propagating messages between nodes and can provides exact answer for polytree models with pure discrete or continuous variables. In addition, applying Pearl's message passing to network with loops usually converges and results in good approximation. However, for hybrid model, there is a need of a general message passing algorithm between different types of variables. In this paper, we develop a method called Direct Message Passing (DMP) for exchanging messages between discrete and continuous variables. Based on Pearl's algorithm, we derive formulae to compute messages for variables in various dependence relationships encoded in conditional probability distributions. Mixture of Gaussian is used to represent continuous messages, with the number of mixture components up to the size of the joint state space of all discrete parents. For polytree Conditional Linear Gaussian (CLG) Bayesian network, DMP has the same computational requirements and can provide exact solution as the one obtained by the Junction Tree (JT) algorithm. However, while JT can only work for the CLG model, DMP can be applied for general nonlinear, non-Gaussian hybrid model to produce approximate solution using unscented transformation and loopy propagation. Furthermore, we can scale the algorithm by restricting the number of mixture components in the messages. Empirically, we found that the approximation errors are relatively small especially for nodes that are far away from

  19. Noise from wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Fegeant, Olivier [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Building Sciences

    2002-02-01

    A rapid growth of installed wind power capacity is expected in the next few years. However, the siting of wind turbines on a large scale raises concerns about their environmental impact, notably with respect to noise. To this end, variable speed wind turbines offer a promising solution for applications in densely populated areas like the European countries, as this design would enable an efficient utilisation of the masking effect due to ambient noise. In rural and recreational areas where wind turbines are sited, the ambient noise originates from the action of wind on the vegetation and about the listener's ear (pseudo-noise). It shows a wind speed dependence similar to that of the noise from a variable speed wind turbine and can therefore mask the latter for a wide range of conditions. However, a problem inherent to the design of these machines is their proclivity to pure tone generation, because of the enhanced difficulty of avoiding structural resonances in the mechanical parts. Pure tones are deemed highly annoying and are severely regulated by most noise policies. In relation to this problem, the vibration transmission of structure-borne sound to the tower of the turbine is investigated, in particular when the tower is stiffened at its upper end. Furthermore, since noise annoyance due to wind turbine is mostly a masking issue, the wind-related sources of ambient noise are studied and their masking potentials assessed. With this aim, prediction models for wind-induced vegetation noise and pseudo-noise have been developed. Finally, closely related to the effect of masking, is the difficulty, regularly encountered by local authorities and wind farm developers, to measure noise immission from wind turbines. A new measurement technique has thus been developed in the course of this work. Through improving the signal-to-noise ratio between wind turbine noise and ambient noise, the new technique yields more accurate measurement results.

  20. An evaluation of the WindEye wind lidar

    OpenAIRE

    Dellwik, Ebba; Sjöholm, Mikael; Mann, Jakob

    2015-01-01

    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 measures the wind speed along two beams to determine the wind direction of the incoming wind field. The field experiment utilized two sonic anemometers located in the two centers of the measurement v...

  1. 40 CFR 205.171-8 - Passing or failing under SEA.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Passing or failing under SEA. 205.171... Passing or failing under SEA. (a) A failing exhaust system is one which, when installed on any motorcycle... equal to the number in Column A, the sample passes. (c) Pass or failure of a SEA takes place when...

  2. Wind speed dynamical model in a wind farm

    DEFF Research Database (Denmark)

    Soleimanzadeh, Maryam; Wisniewski, Rafal

    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, the...

  3. 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 as it is...... for the more traditional onshore wind power, which has been under development since the 1970s. However, offshore projects face extra technical challenges some of which requires in-depth scientific investigations. This article deals with some of the most outstanding challenges concerning the turbine...... structure: the rotor, the nacelle, the tower, and the foundation. Further the determinations of the essential environmental conditions are treated: the wind field, the wave field, the sea current, and the soil conditions. The various options for grid connections, advantages, and disadvantages are discussed...

  4. Wind energy economics

    International Nuclear Information System (INIS)

    The economics of wind energy have improved rapidly in the past few years, with improvements in machine performance and increases in size both contributing to reduce costs. These trends are examined and future costs assessed. As bank loan periods for wind projects are shorter than for thermal plant, the effect on the price of wind energy is discussed. It is argued that wind energy has a higher value than that of centralised plant, since it is fed into the low voltage distribution network and it follows that the price of wind energy is converging with its value. The paper also includes a brief review of the capacity credit of wind plant and an assessment of the cost penalties which are incurred due to the need to hold extra plant on part load. These penalties are shown to be small. (author)

  5. 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...... for the installers, such as the dimension of the wind farm and the difficulty of reaching failed components in case of harsh weather. Each component that affects the assessment must be included and proper models for them are investigated in this thesis. The project provides a survey of available offshore wind farm...... 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...

  6. 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 for......% 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....... 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...

  7. 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....

  8. Wind turbine wake aerodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Vermeer, L.J. [Delft University of Technology (Netherlands). Section Wind Energy; Sorensen, J.N. [Technical University of Denmark, Lyngby (Denmark). Dept. of Mechanical Engineering; Crespo, A. [Universidad Politecnica de Madrid (Spain). Dpto. de Ingenieria Energetica y Fluidomecanica

    2003-10-01

    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 focuses 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. (author)

  9. Wind farm economics

    International Nuclear Information System (INIS)

    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)

  10. Analysis of CAB/UTIL & IFE/PASS SEAT Switch%浅谈CAB/UTIL和IFE/PASS SEAT电门

    Institute of Scientific and Technical Information of China (English)

    郭佳

    2015-01-01

    B737NG飞机P5-13电源面板存在两种构型,“CAB/UTIL”和“IFE/PASS SEAT”属于新构型中的两个电门,本文在结合手册与实际现象的基础上,分析了这两个电门的功用,避免在将来的排故过程中走弯路。%There are two configurations of B737NG aircraft P5-13 power supply panel, the"CAB/UTIL" and"IFE/PASS SEAT"belong to the two switches in the new configuration, based on the combination of manual and actual phenomena, this paper analyzes the function of these switches, to avoid detours during troubleshooting in the future.

  11. Why offshore wind energy?

    OpenAIRE

    Esteban Pérez, María Dolores; Diez Gonzalez, Jose Javier; López Gutiérrez, José Santos; Negro Valdecantos, Vicente

    2011-01-01

    At the beginning of 2010, only 2000 wind megawatts had been installed offshore. Although the first offshore wind farm experiment took place in 1990, most of the facilities built up to now have been pilot projects. Then, offshore wind power can be considered as an incipient market. However, just at this moment, the growth of this technology finally seems to be happening, being several countries at the top of its development (the United Kingdom, Denmark, Holland, Sweden and Germany). This curre...

  12. Wind energy in Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Hanagasioglu, Mehmet [Interwind Ltd., Zurich (Switzerland)

    1999-01-01

    Wind and wind energy has always played an important role in the historical and economical development of Asia Minor and the geographical area covered by the Republic of Turkey today. The ancient city of Troia probably became rich with harbor fees from commercial vessels, which could not sail up the Dardanelles because of strong north-easterly winds and swift currents. As early as 1389 AC wind mills were already dominant landmarks and found their way even into naval maps. In 1940s wind mills ground corn, pumped water to fields and even powered first radio sets at the Anatolian country side. Like elsewhere, with the onsets of oil era and construction of large hydroelectric and fossil fuel power plants this renewable energy sources was forgotten in Turkey until recently. Today there is a serious intention on part of Turkish authorities to promote wind energy. The Ministry of Energy and Natural Resources approved the first B.O.T. wind park with 12 x 600 kW turbines in December 1997 and the contract text was initialled on April 3, 1998. By the time we present this paper this wind park should be in operation along with the first Autoproducer wind park with 3 x 500 kW turbines, which was connected to the grid on February 20, 1998. Efforts to include wind energy also in the B.O.O. Law are also continuing. We at Interwind estimate the usable wind energy potential in Turkey, at around 8,000 MW. However, how much of this potential can be utilised in the near future will depend on three factors; 1) Definition of the specific place of renewable energy sources in the overall energy politics of Turkey. 2) Reinforcement of infrastructure of high wind locations as a matter of priority. 3) Revision of legal frame work for independent power producers to address the realities of the present and demands of the future. (Author)

  13. 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) po......) 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]....

  14. 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.

  15. WindCrete

    OpenAIRE

    Molins i Borrell, Climent; Campos Hortigüela, Alexis

    2016-01-01

    A novel concept of a floating platform for supporting wind turbines (named WindCrete) has been developed at the Universitat Politècnica de Catalunya (UPC) in order to substantially reduce the capital expenditure or CAPEX for floating offshore wind turbines. The concept is based on a monolithic full concrete structure, including the tower and the floater, which also allows a significant reduction of the operating expense, or OPEX. The basics of the concept are presented in this article, includ...

  16. Wind power barometer

    International Nuclear Information System (INIS)

    The worldwide wind power increased by 12.4% in 2013 to reach 318.6 GW but the world market globally decreased by losing 10 GW: only 35.6 GW have been installed in 2013 which is even less than was installed in 2009. This activity contraction is mainly due to the collapse of the American market, American authorities having been late to decide to maintain federal incentives. The European wind power market also contracted in 2013 because of the lack of trust of the investors in the new energy policies of the European governments. In the rest of the world wind energy has kept on growing particularly in China and Canada. At the end of 2013 the cumulated wind power reached 117,73 GW in Europe. About 1.5 MW out of 10 MW of wind power installed in Europe in 2013 come from off-shore wind farms, United-Kingdom and Denmark being the most important players by totalling more than 70% of the off-shore wind power installed at the end of 2013. Various charts and tables give the figures of the wind power cumulated and installed in 2013 in different parts of the world: Europe, North America and Asia, the time evolution of the worldwide wind power since 1995, the wind power cumulated and installed in 2013 for the different countries of Europe and the ratio between the cumulated wind power and the country population. A table lists the main manufacturers of wind turbines and gives their turnover and number of employees at the end of 2013

  17. Wind Turbine Blade Design

    OpenAIRE

    Richard J. Crossley; Peter J. Schubel

    2012-01-01

    A detailed review of the current state-of-art for wind turbine blade design is presented, including theoretical maximum efficiency, propulsion, practical efficiency, HAWT blade design, and blade loads. The review provides a complete picture of wind turbine blade design and shows the dominance of modern turbines almost exclusive use of horizontal axis rotors. The aerodynamic design principles for a modern wind turbine blade are detailed, including blade plan shape/quantity, aerofoil selection ...

  18. Wind Turbine Clutter

    OpenAIRE

    Gallardo-Hernando, Beatriz; Pérez-Martínez, Félix; Aguado-Encabo, Fernando

    2010-01-01

    In this chapter the main effects of wind turbines on the performance of radar systems have been explained. The radar signature of wind turbine clutter is unique and then, it requires a special treatment when developing mitigation techniques. WTC clutter remains spatially static, but it fluctuates continuously in time. In surveillance radars the return from wind turbines can be completely different from one scan to the following. In addition, apart from the powerful tower return, the movement ...

  19. Harnessing the Wind

    Institute of Scientific and Technical Information of China (English)

    Francois; Essomba

    2011-01-01

    Morocco expands its wind energy program to provide much needed clean energy resource THINK of the Kingdom of Morocco and you would not imagine wind farms stretching into the horizon. But the North African country has set itself a windfilled challenge,one that could be a model for sustainable development.Morocco aims to increase its electricity output from wind from its current 280 MW (megawatt) to 2,000 MW by 2020.

  20. Lab 6 winding facility

    International Nuclear Information System (INIS)

    This note describes the winding machine installed by the facility support group at lab 6 in the Fermilab village. It is available for use by outside users and groups within the lab. The machine can wind wire planes whose longest dimension is less than 10 feet. The Wire spacing range has an upper practical limit of about 5mm. Spacing beyond this requires a very long index time and therefore slows down the winding speed prohibitively

  1. Profile and depth prediction in single-pass and two-pass CO2 laser microchanneling processes

    International Nuclear Information System (INIS)

    Polymer based microfluidic channels are used in many chemical and biological devices. Polymethylmethacrylate (PMMA) has emerged as a key material for such devices owing to its high optical transparency and mechanical strength. The use of CO2 laser processing for fabricating microchannels on PMMA has been proved as an efficient and cost effective method. In this work, theoretical models for predicting microchannel profile and depth have been proposed. A model for single-pass laser processing has been proposed based on energy balance. A two-pass laser process for microchannel fabrication produces smoother microchannels with better surface topography and reduced bulging around the microchannel edges. An energy balance based model has also been proposed for two-pass processing. The experimental verification of the proposed models was conducted. Spectroscopic tests were carried out to determine the absorptivity, and simultaneous thermogravimetric analysis/differential scanning calorimetry (TGA/DSC) tests were performed to determine the thermo-physical properties of the PMMA used in the proposed model. The results predicted using the model were found to be in close agreement with the actual values. (paper)

  2. building integrated wind energy

    OpenAIRE

    Wang, Jialin

    2013-01-01

    In considering methods of reducing the emission of carbon dioxide; there is a growing interest for use of wind power at domestic building in U.K. But the technology of wind turbines development in building environment is more complicated than in open areas. Small wind turbines in suburban areas have been reported as having unsatisfactory energy output, but it is not clear whether this is due to insufficient wind resource or low turbine efficiency. The aim of this research is to discover wheth...

  3. Urban Wind Energy

    OpenAIRE

    Beller, Christina

    2011-01-01

    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. However, an overview of the energy content of the wind in cities and how consequently turbines shall be designed for such wind climates is lacking. The objective of the present work is to deliver a...

  4. Offshore Wind Energy

    Energy Technology Data Exchange (ETDEWEB)

    Strach-Sonsalla, Mareike; Stammler, Matthias; Wenske, Jan; Jonkman, Jason; Vorpahl, Fabian

    2016-07-27

    In 1991, the Vindeby Offshore Wind Farm, the first offshore wind farm in the world, started feeding electricity to the grid off the coast of Lolland, Denmark. Since then, offshore wind energy has developed from this early experiment to a multibillion dollar market and an important pillar of worldwide renewable energy production. Unit sizes grew from 450 kW at Vindeby to the 7.5 MW-class offshore wind turbines (OWT ) that are currently (by October 2014) in the prototyping phase. This chapter gives an overview of the state of the art in offshore wind turbine (OWT) technology and introduces the principles of modeling and simulating an OWT. The OWT components -- including the rotor, nacelle, support structure, control system, and power electronics -- are introduced, and current technological challenges are presented. The OWT system dynamics and the environment (wind and ocean waves) are described from the perspective of OWT modelers and designers. Finally, an outlook on future technology is provided. The descriptions in this chapter are focused on a single OWT -- more precisely, a horizontal-axis wind turbine -- as a dynamic system. Offshore wind farms and wind farm effects are not described in detail in this chapter, but an introduction and further references are given.

  5. Small wind turbines

    CERN Document Server

    Wood, David

    2011-01-01

    Small Wind Turbines provides a thorough grounding in analysing, designing, building, and installing a small wind turbine. Small turbines are introduced by emphasising their differences from large ones and nearly all the analysis and design examples refer to small turbines.The accompanying software includes MATLAB(R) programs for power production and starting performance, as well as programs for detailed multi-objective optimisation of blade design. A spreadsheet is also given to help readers apply the simple load model of the IEC standard for small wind turbine safety. Small Wind Turbines repr

  6. Wind energy cost reductions

    International Nuclear Information System (INIS)

    Commercial wind turbines manufactured today reliably generate electrical energy at approximately $0.07 - $0.09 per kWh, depending on the wind speeds at the site and the nature of the terrain. This paper reports that to be competitive with other electricity generation technologies these costs must be reduced 30 - 50% if current electricity pricing practices continue. Reductions of this magnitude can be achieved through reductions in wind turbine capital costs, increases in efficiency, and changes in the financial market's perception of wind energy technology. Advanced technology can make a significant contribution in each of these areas

  7. Wind Turbine Blade Design

    Directory of Open Access Journals (Sweden)

    Richard J. Crossley

    2012-09-01

    Full Text Available A detailed review of the current state-of-art for wind turbine blade design is presented, including theoretical maximum efficiency, propulsion, practical efficiency, HAWT blade design, and blade loads. The review provides a complete picture of wind turbine blade design and shows the dominance of modern turbines almost exclusive use of horizontal axis rotors. The aerodynamic design principles for a modern wind turbine blade are detailed, including blade plan shape/quantity, aerofoil selection and optimal attack angles. A detailed review of design loads on wind turbine blades is offered, describing aerodynamic, gravitational, centrifugal, gyroscopic and operational conditions.

  8. Wind on the moors

    International Nuclear Information System (INIS)

    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)

  9. 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...

  10. Generalized similarity in finite range solar wind magnetohydrodynamic turbulence

    OpenAIRE

    Chapman, S. C.; Nicol, R. M.

    2009-01-01

    Extended or generalized similarity is a ubiquitous but not well understood feature of turbulence that is realized over a finite range of scales. ULYSSES spacecraft solar polar passes at solar minimum provide \\textit{in situ} observations of evolving anisotropic magnetohydrodynamic turbulence in the solar wind under ideal conditions of fast quiet flow. We find a single generalized scaling function characterises this finite range turbulence and is insensitive to plasma conditions. The recent un...

  11. 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

  12. European Wind Atlas and Wind Resource Research in Denmark

    DEFF Research Database (Denmark)

    Mortensen, Niels Gylling

    The assessment of the available and exploitable resource base is naturally of primary concern to any power-producing technology. For wind power, this translates into assessment of the longterm wind speed and wind direction distributions at typical wind turbine hub heights - on a global, national......-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......, regional and local scale. In broad terms, wind resource assessment covers this entire range: from assessing the wind resource on a global scale to estimating the power production of a specific wind turbine at a specific site. Many different tools and techniques have been used for wind resource assessment...

  13. Evaluation of Optimal Distribution of Wind Power Facilities in Iowa for 2015

    Energy Technology Data Exchange (ETDEWEB)

    Factor, T. (Iowa Wind Energy Institute); Milligan, M. (National Renewable Energy Laboratory)

    1999-08-05

    By the end of June 1999, about 250 megawatts of wind generation will have been dedicated in the state of Iowa. This represents the beginning of what is likely to be significant wind capacity development during the next 20 years in the state, as a result of possible public and governmental mandates and consumers' desire for sustainable sources of energy. As the utility industry in the United States moves towards a new structure, renewable energy sources continue to be an important part of new resource development. In this paper, we consider the predicted trends in load growth in Iowa. After accounting for the retirement of nuclear and older fossil fuel facilities over the next 15 years, we estimate Iowa's potential renewable generating capacity through the year 2015 and anticipate the contribution of wind energy to Iowa's portfolio. The Iowa Wind Energy Institute (IWEI) has been monitoring the wind resource in Iowa since June 1994 to obtain wind speed averages at 10, 33 and 50 meters above ground at fourteen geographically dispersed potential wind farm sites. Winds in the Midwest are primarily generated by fronts moving through the region. The Northwest Buffalo Ridge area of Iowa typically has wind speed averages of 7-8 m/s. Central Iowa may have typical winds slightly below this mean value. However, as a front passes through the state, there will be times when a wind farm in Central Iowa will produce more energy than one on Buffalo Ridge.

  14. Do Wind Turbines Affect Weather Conditions?: A Case Study in Indiana

    Directory of Open Access Journals (Sweden)

    Meghan F. Henschen

    2011-01-01

    Full Text Available Wind turbines are becoming increasingly widespread in the United States as the world looks for cleaner sources of energy. Scientists, policymakers, and citizens have strong opinions regarding the positive and negative effects of wind energy projects, and there is a great deal of misinformation about wind energy circulating on the Web and other media sources. The purpose of this study is to gain a better understanding of how the rotation of hundreds of turbines can influence local weather conditions within a wind farm and in the surrounding areas. This experiment measures temperature, atmospheric pressure, wind speed, wind direction, relative humidity, and evaporation with five weather instruments at Meadow Lake Wind Farm located in White, Jasper, and Benton Counties, Indiana, from November 4 through November 18, 2010. The data show that as wind passes throughout the wind farm, the air warms during the overnight and early morning hours and cools during daytime hours. Observed lower humidity rates and higher evaporation rates downwind also demonstrate that the air dries out as it travels through the wind farm. Further research over multiple seasons is necessary to examine the effects of warmer nighttime temperatures and drier conditions progressively downwind of the installation. Nevertheless, wind turbines did not negatively affect local weather patterns in our small-scale research and may actually prevent frost, which could have important positive implications for farmers by potentially prolonging the growing season.

  15. Wind Field Measurements With Airborne Doppler Lidar

    Science.gov (United States)

    Menzies, Robert T.

    1999-01-01

    In collaboration with lidar atmospheric remote sensing groups at NASA Marshall Space Flight Center and National Oceanic and Atmospheric Administration (NOAA) Environmental Technology Laboratory, we have developed and flown the Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS) lidar on the NASA DC-8 research aircraft. The scientific motivations for this effort are: to obtain measurements of subgrid scale (i.e. 2-200 km) processes and features which may be used to improve parameterizations in global/regional-scale models; to improve understanding and predictive capabilities on the mesoscale; and to assess the performance of Earth-orbiting Doppler lidar for global tropospheric wind measurements. MACAWS is a scanning Doppler lidar using a pulsed transmitter and coherent detection; the use of the scanner allows 3-D wind fields to be produced from the data. The instrument can also be radiometrically calibrated and used to study aerosol, cloud, and surface scattering characteristics at the lidar wavelength in the thermal infrared. MACAWS was used to study surface winds off the California coast near Point Arena, with an example depicted in the figure below. The northerly flow here is due to the Pacific subtropical high. The coastal topography interacts with the northerly flow in the marine inversion layer, and when the flow passes a cape or point that juts into the winds, structures called "hydraulic expansion fans" are observed. These are marked by strong variation along the vertical and cross-shore directions. The plots below show three horizontal slices at different heights above sea level (ASL). Bottom plots are enlargements of the area marked by dotted boxes above. The terrain contours are in 200-m increments, with the white spots being above 600-m elevation. Additional information is contained in the original.

  16. 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

  17. Topologically modified teleparallelism, passing through the Nieh-Yan functional

    International Nuclear Information System (INIS)

    Recently, generalizations of the Ashtekar constraints are derived via the Nieh-Yan topological term. To be fair, such canonical transformations have been applied before in a gauge framework of gravity. Moreover, in the case of the teleparallelism equivalent of Einstein's theory, one can go further and show that the Chern-Simons solutions of the Gauss-type constraints wind around torsional instantons, thus establishing an analogue to the θ vacua of Yang-Mills theory.

  18. WIND BRAKING OF MAGNETARS

    Energy Technology Data Exchange (ETDEWEB)

    Tong, H. [Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi, Xinjiang 830011 (China); Xu, R. X.; Qiao, G. J. [KIAA and School of Physics, Peking University, Beijing 100871 (China); Song, L. M., E-mail: tonghao@xao.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2013-05-10

    We explore the wind braking of magnetars considering recent observations challenging the traditional magnetar model. There is evidence for strong multipole magnetic fields in active magnetars, but the dipole field inferred from spin-down measurements may be strongly biased by particle wind. Recent observations challenging the traditional model of magnetars may be explained naturally by the wind braking scenario: (1) the supernova energies of magnetars are of normal value; (2) the non-detection in Fermi observations of magnetars; (3) the problem posed by low magnetic field soft gamma-ray repeaters; (4) the relation between magnetars and high magnetic field pulsars; and (5) a decreasing period derivative during magnetar outbursts. Transient magnetars with L{sub x}<- E-dot{sub rot} may still be magnetic dipole braking. This may explain why low luminosity magnetars are more likely to have radio emissions. A strong reduction of the dipole magnetic field is possible only when the particle wind is very collimated at the star surface. A small reduction of the dipole magnetic field may result from detailed considerations of magnetar wind luminosity. In the wind braking scenario, magnetars are neutron stars with a strong multipole field. For some sources, a strong dipole field may no longer be needed. A magnetism-powered pulsar wind nebula will be one of the consequences of wind braking. For a magnetism-powered pulsar wind nebula, we should see a correlation between the nebula luminosity and the magnetar luminosity. Under the wind braking scenario, a braking index smaller than three is expected. Future braking index measurement of a magnetar may tell us whether magnetars are wind braking or magnetic dipole braking.

  19. WIND BRAKING OF MAGNETARS

    International Nuclear Information System (INIS)

    We explore the wind braking of magnetars considering recent observations challenging the traditional magnetar model. There is evidence for strong multipole magnetic fields in active magnetars, but the dipole field inferred from spin-down measurements may be strongly biased by particle wind. Recent observations challenging the traditional model of magnetars may be explained naturally by the wind braking scenario: (1) the supernova energies of magnetars are of normal value; (2) the non-detection in Fermi observations of magnetars; (3) the problem posed by low magnetic field soft gamma-ray repeaters; (4) the relation between magnetars and high magnetic field pulsars; and (5) a decreasing period derivative during magnetar outbursts. Transient magnetars with Lxrot may still be magnetic dipole braking. This may explain why low luminosity magnetars are more likely to have radio emissions. A strong reduction of the dipole magnetic field is possible only when the particle wind is very collimated at the star surface. A small reduction of the dipole magnetic field may result from detailed considerations of magnetar wind luminosity. In the wind braking scenario, magnetars are neutron stars with a strong multipole field. For some sources, a strong dipole field may no longer be needed. A magnetism-powered pulsar wind nebula will be one of the consequences of wind braking. For a magnetism-powered pulsar wind nebula, we should see a correlation between the nebula luminosity and the magnetar luminosity. Under the wind braking scenario, a braking index smaller than three is expected. Future braking index measurement of a magnetar may tell us whether magnetars are wind braking or magnetic dipole braking.

  20. Wind Braking of Magnetars

    Science.gov (United States)

    Tong, H.; Xu, R. X.; Song, L. M.; Qiao, G. J.

    2013-05-01

    We explore the wind braking of magnetars considering recent observations challenging the traditional magnetar model. There is evidence for strong multipole magnetic fields in active magnetars, but the dipole field inferred from spin-down measurements may be strongly biased by particle wind. Recent observations challenging the traditional model of magnetars may be explained naturally by the wind braking scenario: (1) the supernova energies of magnetars are of normal value; (2) the non-detection in Fermi observations of magnetars; (3) the problem posed by low magnetic field soft gamma-ray repeaters; (4) the relation between magnetars and high magnetic field pulsars; and (5) a decreasing period derivative during magnetar outbursts. Transient magnetars with L_x{rot may still be magnetic dipole braking. This may explain why low luminosity magnetars are more likely to have radio emissions. A strong reduction of the dipole magnetic field is possible only when the particle wind is very collimated at the star surface. A small reduction of the dipole magnetic field may result from detailed considerations of magnetar wind luminosity. In the wind braking scenario, magnetars are neutron stars with a strong multipole field. For some sources, a strong dipole field may no longer be needed. A magnetism-powered pulsar wind nebula will be one of the consequences of wind braking. For a magnetism-powered pulsar wind nebula, we should see a correlation between the nebula luminosity and the magnetar luminosity. Under the wind braking scenario, a braking index smaller than three is expected. Future braking index measurement of a magnetar may tell us whether magnetars are wind braking or magnetic dipole braking.

  1. Wind energy - an overview

    International Nuclear Information System (INIS)

    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

  2. Wind resource estimation and siting of wind turbines

    OpenAIRE

    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 ...

  3. High precision damage-resistant multiple-pass ultraviolet reflectometer

    International Nuclear Information System (INIS)

    A multiple-pass cell was reported by John White in 1942. Since them, it has been adapted for use as a high-precision reflectometer. The multiple-pass reflectometer has been studied and reported by Arnon and Baumeister. Here, a reflectometer which is similar is described. It utilizes a uv laser operating at lambda = 351 nm as the source and the White-cell mirrors are high-reflection dielectric coatings designed for that wavelength. Because of the low-loss reflectors used in the cell, a high number of traversals, reflections, can be achieved; R greater than or equal to 239. The use of dielectric mirrors also improves the damage resistance of the apparatus which is important when a uv laser beam is used. The results of reflectance measurements performed on several ultraviolet high reflectors are also reported. These include conventional dielectric coatings as well as a hybrid coating consisting of Al2O3, HfO2, and SiO2 layers. The Los Alamos optical damage laboratory has observed and defined several types of laser-induced damage to optical materials. In the case of high reflection, multi-layer, dielectric coatings, damage may be defined as any change in the coating layers or at the substrate interface which causes a measurable change in reflectance at its design wavelength. Since most dielectric high reflectors have reflectances approaching unity, and a change caused by laser irradiation can be minute, a precise method for measuring high reflectance must be utilized. A multiple-pass reflectometer based on the White cell was selected because of its demonstratd precision and high accuracy. It utilizes a laser as the source for reasons described later

  4. S-AMP: Approximate Message Passing for General Matrix Ensembles

    DEFF Research Database (Denmark)

    Cakmak, Burak; Winther, Ole; Fleury, Bernard H.

    2014-01-01

    We propose a novel iterative estimation algorithm for linear observation models called S-AMP. The fixed points of S-AMP are the stationary points of the exact Gibbs free energy under a set of (first- and second-) moment consistency constraints in the large system limit. S-AMP extends the...... approximate message-passing (AMP) algorithm to general matrix ensembles with a well-defined large system size limit. The generalization is based on the S-transform (in free probability) of the spectrum of the measurement matrix. Furthermore, we show that the optimality of S-AMP follows directly from its...

  5. Easy fabrication of a tunable high-pass birdcage resonator.

    Science.gov (United States)

    Xu, Y; Tang, P

    1997-07-01

    A practical design for a high-pass birdcage resonator is presented. Precision seamless telescoping tubes were used for easy tuning of resonant frequency by adjusting the length of the coils. Three probes, of 4.4, 5.0, and 25.0 cm in diameter, respectively, were constructed and tested. An empirical formula is given that can be used to calculate the capacitance needed for a given frequency when the desired physical dimension and the number of elements of the coll are specified. A simple three-step procedure is suggested for easy fabrication of resonators that are routinely tunable over tens of megahertz. PMID:9211393

  6. Low-pass sequencing for microbial comparative genomics

    Directory of Open Access Journals (Sweden)

    Kennedy Sean

    2004-01-01

    Full Text Available Abstract Background We studied four extremely halophilic archaea by low-pass shotgun sequencing: (1 the metabolically versatile Haloarcula marismortui; (2 the non-pigmented Natrialba asiatica; (3 the psychrophile Halorubrum lacusprofundi and (4 the Dead Sea isolate Halobaculum gomorrense. Approximately one thousand single pass genomic sequences per genome were obtained. The data were analyzed by comparative genomic analyses using the completed Halobacterium sp. NRC-1 genome as a reference. Low-pass shotgun sequencing is a simple, inexpensive, and rapid approach that can readily be performed on any cultured microbe. Results As expected, the four archaeal halophiles analyzed exhibit both bacterial and eukaryotic characteristics as well as uniquely archaeal traits. All five halophiles exhibit greater than sixty percent GC content and low isoelectric points (pI for their predicted proteins. Multiple insertion sequence (IS elements, often involved in genome rearrangements, were identified in H. lacusprofundi and H. marismortui. The core biological functions that govern cellular and genetic mechanisms of H. sp. NRC-1 appear to be conserved in these four other halophiles. Multiple TATA box binding protein (TBP and transcription factor IIB (TFB homologs were identified from most of the four shotgunned halophiles. The reconstructed molecular tree of all five halophiles shows a large divergence between these species, but with the closest relationship being between H. sp. NRC-1 and H. lacusprofundi. Conclusion Despite the diverse habitats of these species, all five halophiles share (1 high GC content and (2 low protein isoelectric points, which are characteristics associated with environmental exposure to UV radiation and hypersalinity, respectively. Identification of multiple IS elements in the genome of H. lacusprofundi and H. marismortui suggest that genome structure and dynamic genome reorganization might be similar to that previously observed in the

  7. Line-item veto may pass this month

    Science.gov (United States)

    U.S. House and Senate Republicans have cleared the way for legislation to give the President the power of a line-item-veto in time for the 1998 budget season.The line-item veto, as proposed, would allow the President to remove from appropriations bills selected appropriations items, new entitlement spending, or narrowly targeted tax breaks. Once a line item is cut from the budget, Congress would have to pass a separate appropriations bill for that individual item; that new, separate bill would then be subject to the traditional Presidential veto.

  8. Time Really Passes, Science Can't Deny That

    CERN Document Server

    Gisin, Nicolas

    2016-01-01

    Today's science provides quite a lean picture of time as a mere geometric evolution parameter. I argue that time is much richer. In particular, I argue that besides the geometric time, there is creative time, when objective chance events happen. The existence of the latter follows straight from the existence of free-will. Following the french philosopher Lequyer, I argue that free-will is a prerequisite for the possibility to have rational argumentations, hence can't be denied. Consequently, science can't deny the existence of creative time and thus that time really passes.

  9. Maximum Matching in Semi-Streaming with Few Passes

    OpenAIRE

    Konrad, Christian; Magniez, Frédéric; Mathieu, Claire

    2011-01-01

    In the semi-streaming model, an algorithm receives a stream of edges of a graph in arbitrary order and uses a memory of size $O(n \\mbox{ polylog } n)$, where $n$ is the number of vertices of a graph. In this work, we present semi-streaming algorithms that perform one or two passes over the input stream for maximum matching with no restrictions on the input graph, and for the important special case of bipartite graphs that we refer to as maximum bipartite matching (MBM). The Greedy matching al...

  10. Can Lionel Messi's brain slow down time passing?

    Science.gov (United States)

    Jafari, Sajad; Smith, Leslie Samuel

    2016-01-01

    It seems that seeing others in slow-motion by heroes does not belong only to movies. When Lionel Messi plays football, you can hardly see anything from him that other players cannot do. Then why he is not stoppable really? It seems the answer may be that opponents do not have enough time to do what they want; because in Messi's neural system, time passes slower. In differential equations that model a single neuron, this speed can be generated by multiplying an equal term in all equations. Or maybe interactions between neurons and the structure of neural networks play this role. PMID:27010676

  11. Algorithmic Verification of Single-Pass List Processing Programs

    OpenAIRE

    Alur, Rajeev; Cerny, Pavol

    2010-01-01

    We introduce streaming data string transducers that map input data strings to output data strings in a single left-to-right pass in linear time. Data strings are (unbounded) sequences of data values, tagged with symbols from a finite set, over a potentially infinite data domain that supports only the operations of equality and ordering. The transducer uses a finite set of states, a finite set of variables ranging over the data domain, and a finite set of variables ranging over data strings. A...

  12. PENN PASS: a program for graduates of foreign dental schools.

    Science.gov (United States)

    Berthold, P; Lopez, N

    1994-01-01

    An increasing number of graduates of foreign dental schools who enroll in advanced standing programs to qualify for licensure calls for dental schools to be prepared to handle not only the curricular demands but also the growing cultural diversity among its student population. The "reeducation" of this student group not only meets the need of foreign dentists for an American degree but may also provide health professionals to service various ethnic populations whose language and culture they are able to understand and identify with. A survey of students and graduates of a two-year Program for Advanced Standing Students (PASS) for graduates of foreign dental schools representing 34 countries aimed to arrive at an understanding of this student group through characterization of the foreign dentists and identification of their attitudes and feelings toward various aspects of the program, the school and faculty and their experience of stress. This report includes description of the distinctive features of the program which cater to specific needs and concerns of this non-traditional group of dental students. PASS students are accepted on the basis of their grades in dental school in home country, scores in the National Dental Board Examination Part I, Test of English as Foreign Language (TOEFL), and ratings in personal interviews. They complete an intensive summer program consisting of didactic and laboratory courses which prepares them for integration with four-year students for the last two years of didactic and clinical curriculum. Cultural diversity seminars, a special English class, PASS class meetings and seminars are unique additions to their program and aim to assist them adjust to the educational, social and cultural systems in an American school. Results of the survey show a majority of the PASS students feel that they are part of the school and that there is someone in the school whom they can approach for problems. An understanding of their ethnic and

  13. Fault-tolerant Agreement in Synchronous Message-passing Systems

    CERN Document Server

    Raynal, Michel

    2010-01-01

    The present book focuses on the way to cope with the uncertainty created by process failures (crash, omission failures and Byzantine behavior) in synchronous message-passing systems (i.e., systems whose progress is governed by the passage of time). To that end, the book considers fundamental problems that distributed synchronous processes have to solve. These fundamental problems concern agreement among processes (if processes are unable to agree in one way or another in presence of failures, no non-trivial problem can be solved). They are consensus, interactive consistency, k-set agreement an

  14. n-Body simulations using message passing parallel computers

    Energy Technology Data Exchange (ETDEWEB)

    Grama, A.Y.; Kumar, V.; Sameh, A. [Univ. of Minnesota, Minneapolis, MN (United States)

    1995-12-01

    In this paper, we present new parallel formulations of the Barnes-Hut method for n-body simulations on message passing computers. These parallel formulations partition the domain efficiently incurring minimal communication overhead. This is in contrast to existing schemes that are based on sorting a large number of keys or on the use of global data structures. The new formulations are augmented by alternate communication strategies which serve to minimize communication overhead. The impact of these communication strategies is experimentally studied. We report on experimental results obtained from an astrophysical simulation on an nCUBE2 parallel computer.

  15. n-body simulations using message passing parallel computers.

    Science.gov (United States)

    Grama, A. Y.; Kumar, V.; Sameh, A.

    The authors present new parallel formulations of the Barnes-Hut method for n-body simulations on message passing computers. These parallel formulations partition the domain efficiently incurring minimal communication overhead. This is in contrast to existing schemes that are based on sorting a large number of keys or on the use of global data structures. The new formulations are augmented by alternate communication strategies which serve to minimize communication overhead. The impact of these communication strategies is experimentally studied. The authors report on experimental results obtained from an astrophysical simulation on an nCUBE2 parallel computer.

  16. A Natural Gas Field Research Project Passed Acceptance

    Institute of Scientific and Technical Information of China (English)

    Liang Hongguang; Wang Weiyuan

    1996-01-01

    @@ Based on the fact that all sub-topics had passed acceptance and appraised, a research project entitled "The study on formation condition, distribution and exploration technology of large and medium sized natural gas field (project No. 85-102)" was finally accepted and appraised by State Planning Commission on January 11, 1996. The research project is a state key scientific research project in the "Eighth Five-Year Plan" jointly undertaken by CNPC,Ministry of Geology and Mineral Resources of the P.R.C.,CNOOC and Chinese Academy of Sciences (CAS).

  17. Uniqueness Typing for Resource Management in Message-Passing Concurrency

    CERN Document Server

    de Vries, Edsko; Hennessy, Matthew; 10.4204/EPTCS.22.3

    2010-01-01

    We view channels as the main form of resources in a message-passing programming paradigm. These channels need to be carefully managed in settings where resources are scarce. To study this problem, we extend the pi-calculus with primitives for channel allocation and deallocation and allow channels to be reused to communicate values of different types. Inevitably, the added expressiveness increases the possibilities for runtime errors. We define a substructural type system which combines uniqueness typing and affine typing to reject these ill-behaved programs.

  18. Regional wind-field study in complex terrain during summer sea-breeze conditions

    International Nuclear Information System (INIS)

    A regional-scale data base, consisting of wind and temperature data for June and July of 1977, was developed for the greater San Francisco Bay Area and eastward to the Central Valley. Continuous meteorological measurements were made in the area of a windy pass (Patterson Pass) 3 km east of Lawrence Livermore Laboratory. This area was chosen because of its complex terrain and importance as a downwind topographic feature affecting the dispersal of possible accidental atmospheric releases from the Laboratory and as an area of high wind-energy potential. The results of this study provided the following: (1) a data base, including over 50 stations for use in numerical wind-field regional-scale-model validation; (2) characterization of summer sea breese oscillations of approx. 6 and 12 days (this analysis is useful in calculating wind-power persistence and in understanding summer sea-breeze mechanisms in the Bay Area); and (3) successful application of an optical space-averaging wind sensor over a 1-km path across a pass to provide long-path averaged data more suitable for regional, numerical wind-field models with kilometre-size grid elements

  19. Offshore wind resource estimation for wind energy

    OpenAIRE

    Hasager, Charlotte Bay; Badger, Merete; Mouche, A.; Karagali, Ioanna; Astrup, Poul; Nielsen, Morten; Bingöl, Ferhat; Pena Diaz, Alfredo; Larsén, Xiaoli Guo; Badger, Jake; Hahmann, Andrea N.; Mikkelsen, Torben; Gryning, Sven-Erik

    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 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 win...

  20. Wind Turbine Box - energy fluxes around a characteristic wind turbine

    Science.gov (United States)

    Calaf, Marc; Cortina, Gerard; Sharma, Varun

    2015-11-01

    This research project presents a new tool, so called ``Wind Turbine Box'', that allows for the direct comparison between the flow around a single wind turbine and the flow around a characteristic wind turbine immersed within a large wind farm. The Wind Turbine Box consists of a limited control volume defined around each wind turbine that is timely co-aligned with each corresponding turbine's yaw-angle. Hence it is possible to extract flow statistics around each wind turbine, regardless of whether the turbine is fully isolated or it is plunged within a large wind farm. The Wind Turbine Box tool has been used to compute the energy fluxes around a characteristic wind turbine of a large wind farm to better understand the wake replenishment processes throughout a complete diurnal cycle. The effective loading of the wind farm has been gradually increased, ranging from quasi-isolated wind turbines to a highly packed wind farm. For this purpose, several Large Eddy Simulations have been run, forced with a constant geostrophic wind and a time varying surface temperature extracted from a selected period of the CASES-99 field experiment. Results illustrate the differences in the flow dynamics as it evolves around a characteristic wind turbine within a large wind farm and its asymptotic transition to the fully developed wind turbine array boundary layer.

  1. Reap the Wind

    Institute of Scientific and Technical Information of China (English)

    Ni Yanshuo

    2011-01-01

    @@ DEVELOPING clean energy, especially wind power, occupies a prominent position in ('hina's 12th Five-Year Plan, the country's development guideline for the next five years starting 2011.During its 11th Five-Year Plan period from 2006-10, China's wind power industry has already moved from trailing the pack to being a world leader.

  2. Wind machine. Windkraftmaschine

    Energy Technology Data Exchange (ETDEWEB)

    Koerber, E.

    1979-03-05

    The invention refers to a wind machine, with a guide device which can rotate around a vertical axis, which contains a wedge surface made as a solar collector with a wind rotor situated on a wheel of the wedge surface, particularly a Savonius rotor. This invention is characterised by the fact that the guide device is provided with a single wedge surface which can rotate on the end of the axis and is at an angle to the ground, where the wind rotor is fixed to the top edge of the wedge surface parallel to the ground. A feedback device is provided, which makes possible a rotation of the wedge surface around the axis in the direction of the wind, independent of the sun's position but depending on the wind, where the wedge surface is movable around the axis opposite to the torque due to wind pressure. This feedback device has a counterweight suspended on a cord below the wedge surface near the wind rotor. Further, there is an automatically driven device to rotate the wedge surface plus the wind rotor, depending on the time of day.

  3. Fashion Wind from Shishi

    Institute of Scientific and Technical Information of China (English)

    Zhao Fei

    2011-01-01

    On October 17th, 2011, the topic release of Shishi city named "Fashion Wind from Shishi" was staged in Shanghai. As a major fashion festival of Chinese Fashion League's fashion release in 2011, Shishi is blowing waves of brilliant fashion wind from both sides of the Taiwan Straits toward China and the world

  4. The wind farm business

    International Nuclear Information System (INIS)

    This article highlights the tasks to be undertaken by the wind farm business starting with the initial site selection, through the planning stage and the consideration of technical matters, to the implementation and financial aspects. The current situation in the UK with regard to installed wind turbines, public attitude, and future prospects are discussed. (UK)

  5. Assessing offshore wind potential

    International Nuclear Information System (INIS)

    Quantifying wind potential is a pivotal initial step in developing and articulating a state’s policies and strategies for offshore wind industry development. This is particularly important in the Great Lakes States where lessons from other offshore environments are not directly applicable. This paper presents the framework developed for conducting a preliminary assessment of offshore wind potential. Information on lake bathymetry and wind resources were combined in simulating alternative scenarios of technically feasible turbine construction depths and distance concerns by stakeholders. These yielded estimates of developable offshore wind areas and potential power generation. While concerns about the visibility of turbines from shore reduce the power that can be generated, engineering solutions that increase the depths at which turbines can be sited increase such potential power output. This paper discusses the costs associated with technical limitations on depth and the social costs related to public sentiments about distance from the shoreline, as well as the possible tradeoffs. The results point to a very large untapped energy resource in the Michigan’s Great Lakes, large enough to prompt policy action from the state government. - Highlights: ▶ We build a theoretical framework for modeling offshore wind power production. ▶ Illustration of the impact of technology and social limitations on offshore wind energy development. ▶ Geospatial modeling of the offshore wind potential of the Great Lakes.

  6. 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....

  7. Blowin' in the wind

    OpenAIRE

    Wassink, J.

    2008-01-01

    The new Open Jet Facility wind tunnel, which is scheduled to blow its first wind on 24 October, has been a project in the mind of designer Nando Timmer for over twenty years. "I have had moments when I thought it was never going to happen."

  8. 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…

  9. Slow Down the Wind

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    China facing challenge of transforming its wind power the industry for more rational development At its birth in 2008,China Wind Power (CWP) exhibition only attracted 200 exhibitors,and the exhibition area only covered 10,000 square meters.Three years later,CWP 2011 attracted more

  10. Wind energy barometer

    International Nuclear Information System (INIS)

    After a bear market in 2013, wind energy industry has rebounded worldwide to reach a top in installed power. More than 52 GW of wind turbines were installed in 2014 worldwide while less than 37 GW were installed in 2013. More than half of the total GW of wind energy installed in 2014 were implemented in Asia. The cumulated installed capacity reached 371 GW at the end of 2014. When we consider the cumulated wind power installed per inhabitant in Europe, Denmark ranks first with 862 W, Sweden ranks second with 562 W and Germany ranks third with 501 W. Concerning the production of electricity with wind energy, the 4 most important producers in Europe are Germany (55.969 TWh), Spain (51.138 TWh), United Kingdom (31.450 TWh) and France (17.000 TWh). Some studies show that if we take into account some external costs like air quality, climate change or toxicity for man, wind energy would be the cheapest with a cost of 105 euros/MWh compared with 164 euros/MWh for natural gas and 133 euros/MWh for nuclear power. The cost of offshore wind energy (186 euros/MWh) could be reduced by using more and more powerful wind turbines. (A.C.)

  11. Wind farm economics

    International Nuclear Information System (INIS)

    The important parameters involved in the operational success of a wind farm are discussed from the point of view of an experienced wind turbine company. The most important is the proper evaluation of the available wind resource, taking into account not only the average wind speed but also wind distribution and other site-specific conditions. The next factor is the financing conditions, especially the length of loan terms and the interest rate. After installation, the availability should be at least 95% and regular service and maintenance should be provided at all times. Finally, total costs for the lifetime of the wind farm should be taken into consideration before the final choice of a wind turbine is made. Soft costs such as legal fees should be carefully controlled, and preferably the investing parties should do as much of this type of work themselves if possible. If the circumstances are right, adequate preparation is done, and the investment is regarded as a long-term one, it is possible to make a reasonable profit from wind energy

  12. Harnessing the Wind

    Institute of Scientific and Technical Information of China (English)

    Francois Essomba

    2011-01-01

    THINK of the Kingdom of Morocco and you would not imagine wind farms stretching into the horizon.But the North African country has set itself a windfilled challenge,one that could be a model for sustainable development.Morocco aims to increase its electricity output from wind from its current 280 MW (megawatt) to 2,000 MW by 2020.

  13. Wind turbines and infrasound

    Energy Technology Data Exchange (ETDEWEB)

    Howe, B. [HGC Engineering, Mississauga, ON (Canada)

    2006-11-29

    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.

  14. The Dutch wind turbine industry

    International Nuclear Information System (INIS)

    An overview is given of the manufacturers of wind turbines and wind turbine blades in the Netherlands. Special attention is paid to the impact of the Dutch Integral Program Wind energy (IPW) on the developments and activities of the Dutch wind turbine industry. Implementation of wind energy is less than expected. The activities to reduce the prices for wind turbines have not yet resulted in cheaper wind turbines. The efficiency of wind energy however does not only depend on the costs for wind turbines but also on the value adjudged to the electric power from wind energy. Implementation of wind turbines must be better planned based on the condition that the developments in the wind turbine industry should be continued. Problems regarding the selection of sites and licensing procedures have to be solved. 4 tabs

  15. Type IV Wind Turbine Model

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Margaris, Ioannis D.

    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....... In the project, this wind turbine model will be further incorporated in a wind power plant model together with the implementation in the wind power control level of the new control functionalities (inertial response, synchronising power and power system damping). For this purpose an aggregate wind...... power plant (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...

  16. High-efficiency wind turbine

    Science.gov (United States)

    Hein, L. A.; Myers, W. N.

    1980-01-01

    Vertical axis wind turbine incorporates several unique features to extract more energy from wind increasing efficiency 20% over conventional propeller driven units. System also features devices that utilize solar energy or chimney effluents during periods of no wind.

  17. 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.

  18. UAVSAR - A New Airborne L-Band Radar for Repeat Pass Interferometry

    Science.gov (United States)

    Mace, Thomas H.; Lou, Yunling

    2009-01-01

    NASA/JPL has developed a new airborne Synthetic Aperture Radar (SAR) which has become available for use by the scientific community in January, 2009. Pod mounted, the UAVSAR was designed to be portable among a variety of aircraft, including unmanned aerial systems (UAS). The instrument operates in the L-Band, has a resolution under 2m from a GPS altitude of 12Km and a swath width of approximately 20Km. UAVSAR currently flies on a modified Gulfstream-III aircraft, operated by NASA s Dryden Flight Research Center at Edwards, California. The G-III platform enables repeat-pass interferometric measurements, by using a modified autopilot and precise kinematic differential GPS to repeatedly fly the aircraft within a specified 10m tube. The antenna is electronically steered along track to assure that the antenna beam can be directed independently, regardless of speed and wind direction. The instrument can be controlled remotely, AS AN OPTION, using the Research Environment for Vehicle Embedded Analysis on Linux (REVEAL). This allows simulation of the telepresence environment necessary for flight on UAS. Potential earth science research and applications include surface deformation, volcano studies, ice sheet dynamics, and vegetation structure.

  19. A meteorological and snow observational data set from Snoqualmie Pass (921 m), Washington Cascades, USA

    Science.gov (United States)

    Wayand, Nicholas E.; Massmann, Adam; Butler, Colin; Keenan, Eric; Stimberis, John; Lundquist, Jessica D.

    2015-12-01

    We introduce a quality controlled observational atmospheric, snow, and soil data set from Snoqualmie Pass, Washington, USA, to enable testing of hydrometeorological and snow process representations within a rain-snow transitional climate where existing observations are sparse and limited. Continuous meteorological forcing (including air temperature, total precipitation, wind speed, specific humidity, air pressure, and short and longwave irradiance) are provided at hourly intervals for a 24 year historical period (water years 1989-2012) and at half-hourly intervals for a more recent period (water years 2013-2015), separated based on the availability of observations. The majority of missing data were filled with biased-corrected reanalysis model values (using NLDAS). Additional observations include 40 years of snow board new snow accumulation, multiple measurements of total snow depth, and manual snow pits, while more recent years include subdaily surface temperature, snowpack drainage, soil moisture and temperature profiles, and eddy covariance-derived turbulent heat flux. This data set is ideal for testing hypotheses about energy balance, soil, and snow processes in the rain-snow transition zone.

  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. 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...... 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 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 the...

  2. 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...... 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...... % under ideal 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....

  3. 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, the...

  4. Wind power forecast

    Energy Technology Data Exchange (ETDEWEB)

    Pestana, Rui [Rede Electrica Nacional (REN), S.A., Lisboa (Portugal). Dept. Systems and Development System Operator; Trancoso, Ana Rosa; Delgado Domingos, Jose [Univ. Tecnica de Lisboa (Portugal). Seccao de Ambiente e Energia

    2012-07-01

    Accurate wind power forecast are needed to reduce integration costs in the electric grid caused by wind inherent variability. Currently, Portugal has a significant wind power penetration level and consequently the need to have reliable wind power forecasts at different temporal scales, including localized events such as ramps. This paper provides an overview of the methodologies used by REN to forecast wind power at national level, based on statistical and probabilistic combinations of NWP and measured data with the aim of improving accuracy of pure NWP. Results show that significant improvement can be achieved with statistical combination with persistence in the short-term and with probabilistic combination in the medium-term. NWP are also able to detect ramp events with 3 day notice to the operational planning. (orig.)

  5. Wind Farms: Modeling and Control

    OpenAIRE

    Soleimanzadeh, Maryam

    2012-01-01

    In this project a dynamical model has been developed for the wind flow in wind farms. The wind farm model is based on the linearized Navier-Stokes equation combined with momentum theory. The model provides an approximate knowledge of what is happening downstream wind farm, and is represented in the form of ordinary differential equations to be applied in classic control algorithms. The wind farm control algorithms provide the power reference signal for each wind turbine of the farm such that ...

  6. Multi-Pass Approach for Mobile Terrestrial Laser Scanning

    Science.gov (United States)

    Nolan, J.; Eckels, R.; Evers, M.; Singh, R.; Olsen, M. J.

    2015-08-01

    Mobile Terrestrial Laser Scanning (MTLS) has been utilised for an increasing number of corridor surveys. Current MTLS surveys require that many targets be placed along the corridor to monitor the MTLS trajectory's accuracy. These targets enable surveyors to directly evaluate the magnitude of GNSS errors at regular intervals and can also be used to adjust the trajectory to the survey control. However, this "Multi-Target" approach (MTA) is an onerous task that can significantly reduce efficiency. It also is inconvenient to the travelling public, as lanes are often blocked and traffic slowed to permit surveyors to work safely along the road corridor. This paper introduces a "Multi-Pass" approach (MPA), which minimises the number of targets required for monitoring the GNSS-controlled trajectory while still maintaining strict engineering accuracies. MPA uses the power of multiple, independent MTLS passes with different GNSS constellations to generate a "Control Polyline" from the point cloud for the corridor. The Control Polyline can be considered as a statistically valid survey measurement and be incorporated in a network adjustment to strengthen a control network by identifying outliers. Results from a test survey at the MTLS course maintained by the Oregon Department of Transportation illustrate the effectiveness of this approach.

  7. A SECURITY STRATEGY AGAINST STEAL-AND-PASS CREDENTIAL ATTACKS

    Directory of Open Access Journals (Sweden)

    Juan Ceballos

    2016-01-01

    Full Text Available Stealing and passing credentials is currently one of the preferred cyberattack techniques within the hacking community as shown by the increasing number of related incidents over the last years. Instead of targeting passwords, attackers focus on obtaining derived credentials like hashes and session tickets. This type of credentials facilitates taking advantage of omnipresent background mechanisms like Single Sign-On. A combination of malware and penetration tools is used in order to exploit architecture vulnerabilities and steal the credentials. Vulnerabilities also allow the attacker to get access to other systems and covertly take the control of central infrastructure like Active Directory. The ultimate goal is not creating damage that can be noticed but covertly and constantly leaking confidential information for profit or cyber spionage.This paper proposes a comprehensive strategy of six points against steal-and-pass credential attacks and is intended to mitigate the risk significantly. Even if some points of the strategy can be considered security best-practices, other points require the establishment of technical and process controls that are not part of typical security management programs. Controls have to be regularly reviewed as part of security audits, since administrators and other privileged users have often the means to remove or bypass technical controls

  8. Some Difficult-to-pass Tests of Randomness

    Directory of Open Access Journals (Sweden)

    George Marsaglia

    2002-01-01

    Full Text Available We describe three tests of randomness-- tests that many random number generators fail. In particular, all congruential generators-- even those based on a prime modulus-- fail at least one of the tests, as do many simple generators, such as shift register and lagged Fibonacci. On the other hand, generators that pass the three tests seem to pass all the tests in the Diehard Battery of Tests. Note that these tests concern the randomness of a generator's output as a sequence of independent, uniform 32-bit integers. For uses where the output is converted to uniform variates in [0,1, potential flaws of the output as integers will seldom cause problems after the conversion. Most generators seem to be adequate for producing a set of uniform reals in [0,1, but several important applications, notably in cryptography and number theory-- for example, establishing probable primes, complexity of factoring algorithms, random partitions of large integers-- may require satisfactory performance on the kinds of tests we describe here.

  9. Tools for PV (photovoltaic) plant operators: Nowcasting of passing clouds

    International Nuclear Information System (INIS)

    The response time of a PV (photovoltaic) plant is very short and its output power follows the abrupt change in solar irradiance level due to alternate shadow by clouds. The sunshine number (SSN) is a Boolean quantity stating whether the sun is covered by clouds or not, thus being an appropriate parameter to predict the occurrence of direct solar radiation at ground level. Various ARIMA (Autoregressive Integrated Moving Average) models for SSN nowcasting are inferred and discussed in this paper. Actinometric and meteorological data measured at 15 s lag during June 2010 in Timisoara (Romania) are used. The forecasting accuracy is studied as a function of season, of the procedure used to obtain a binary time series and of the type of white noise distribution, respectively. It is demonstrated that the ARIMA(0,1,0) model forecasts SSN with the same accuracy as higher order ARIMA models. The forecasting accuracy decreases when the instability of the radiative regime increases. - Highlights: • Nowcasting of passing clouds is modeled by using a 15 s lag database. • ARIMA (Autoregressive Integrated Moving Average) (0,1,0) model is mostly recommended for nowcasting of passing clouds. • Models accuracy increases by increasing the radiative regime stability

  10. Single Pass Seed Selection Algorithm for k-Means

    Directory of Open Access Journals (Sweden)

    K. K. Pavan

    2010-01-01

    Full Text Available Problem statement: The k-means method is one of the most widely used clustering techniques for various applications. However, the k-means often converges to local optimum and the result depends on the initial seeds. Inappropriate choice of initial seeds may yield poor results. k-means++ is a way of initializing k-means by choosing initial seeds with specific probabilities. Due to the random selection of first seed and the minimum probable distance, the k-means++ also results different clusters in different runs in different number of iterations. Approach: In this study we proposed a method called Single Pass Seed Selection (SPSS algorithm as modification to k-means++ to initialize first seed and probable distance for k-means++ based on the point which was close to more number of other points in the data set. Result: We evaluated its performance by applying on various datasets and compare with k-means++. The SPSS algorithm was a single pass algorithm yielding unique solution in less number of iterations when compared to k-means++. Experimental results on real data sets (4-60 dimensions, 27-10945 objects and 2-10 clusters from UCI demonstrated the effectiveness of the SPSS in producing consistent clustering results. Conclusion: SPSS performed well on high dimensional data sets. Its efficiency increased with the increase of features in the data set; particularly when number of features greater than 10 we suggested the proposed method.

  11. Evaluation of small wind turbines in distributed arrangement as sustainable wind energy option for Barbados

    International Nuclear Information System (INIS)

    The island of Barbados is 99% dependent on fossil fuel imports to satisfy its energy needs, which is unsustainable. This study proposes a 10 MW distributed wind energy scheme using micro wind turbines (WT) of horizontal (HAWT) and vertical axis (VAWT) configurations. These units are rated less than 500 W, and the scheme is hereafter referred to as mWT10. mWT10 is compared to the proposed 10 MW medium WT farm by the Barbados Light and Power Company (BL and P). The economic bottom line is the levelized cost of electricity (LCOE). The results highlight the BL and P proposal as the best economic option at BDS$0.19 per kWh, while that of both mWT10 configurations exceeds the conventional cost of BDS$0.25 by two to nine times. This is attributed to significantly higher relative installation and operational costs. However, the financial gap between mWT10 LCOE and the retail price of electricity is much smaller due to a large fuel surcharge passed on to each customer. Annual additional benefits of using wind energy include: greenhouse gas emissions savings of 6-23 kt of carbon dioxide; and anavoided fuel costs of BDS$1.5-5.3 million. The distributed mWT10 using HAWTs competes directly with the BL and P farm, however, it provides these benefits without the visual or ecological impacts of the larger machines. Conversely, VAWTs have features that favour a visually discrete and widely repeatable scheme but suffer relatively high costs. Therefore, this study illustrates the great potential of small wind turbines to be competitive with conventional wind farms, thus challenging the small wind industry to meet its potential by producing reliable and robust machines at lower cost. (author)

  12. Evaluation of small wind turbines in distributed arrangement as sustainable wind energy option for Barbados

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, Justin D.K.; Amaratunga, Gehan A.J. [University of Cambridge, Department of Engineering, 9 JJ Thomson Avenue, Cambridge CB3 0FA, England (United Kingdom)

    2008-06-15

    The island of Barbados is 99% dependent on fossil fuel imports to satisfy its energy needs, which is unsustainable. This study proposes a 10 MW distributed wind energy scheme using micro wind turbines (WT) of horizontal (HAWT) and vertical axis (VAWT) configurations. These units are rated less than 500 W, and the scheme is hereafter referred to as mWT10. mWT10 is compared to the proposed 10 MW medium WT farm by the Barbados Light and Power Company (BL and P). The economic bottom line is the levelized cost of electricity (LCOE). The results highlight the BL and P proposal as the best economic option at BDS$0.19 per kWh, while that of both mWT10 configurations exceeds the conventional cost of BDS$0.25 by two to nine times. This is attributed to significantly higher relative installation and operational costs. However, the financial gap between mWT10 LCOE and the retail price of electricity is much smaller due to a large fuel surcharge passed on to each customer. Annual additional benefits of using wind energy include: greenhouse gas emissions savings of 6-23 kt of carbon dioxide; and anavoided fuel costs of BDS$1.5-5.3 million. The distributed mWT10 using HAWTs competes directly with the BL and P farm, however, it provides these benefits without the visual or ecological impacts of the larger machines. Conversely, VAWTs have features that favour a visually discrete and widely repeatable scheme but suffer relatively high costs. Therefore, this study illustrates the great potential of small wind turbines to be competitive with conventional wind farms, thus challenging the small wind industry to meet its potential by producing reliable and robust machines at lower cost. (author)

  13. Offshore wind energy prospects

    International Nuclear Information System (INIS)

    In last two years offshore wind energy is becoming a focal point of national and non national organisations particularly after the limitations of fossil fuel consumption, adopted by many developed countries after Kyoto conference at the end of 1997 on global climate change. North Europe is particularly interested in offshore for the limited land areas still available, due to the intensive use of its territory and its today high wind capacity. Really the total wind capacity in Europe could increase from the 1997 value of 4450 MW up to 40 000 MW within 2010, according the White Paper 1997 of the European Commission; a significant percentage (25%) could be sited offshore up to 10 000 MW, because of close saturation of the land sites at that time. World wind capacity could increase from the 1997 value of 7200 MW up to 60 000 MW within 2010 with a good percentage (20%) offshore 12 000 MW. In last seven years wind capacity in shallow water of coastal areas has reached 34 MW. Five wind farms are functioning in the internal seas of Netherlands, Denmark, Sweden; however such siting is mostly to be considered as semi-offshore condition. Wind farms in real offshore sites, open seas with waves and water depth over 10 m, are now proposed in North Sea at 10-20 km off the coasts of Netherlands, Denmark using large size wind turbine (1-2 MW). In 1997 an offshore proposal was supported in Netherlands by Greenpeace after the OWEMES '97 seminar, held in Italy on offshore wind in the spring 1997. A review is presented in the paper of European offshore wind programs with trends in technology, economics and siting effects. (Author)

  14. 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...

  15. Strongly at the wind; Hart am Wind

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Niels Hendrik

    2013-11-01

    The company Easywind from North Friesland distributes a certified and stromproof small wind turbine. More than 300 systems have been sold. In Germany especially farmers and small businesses meet their needs so. [German] Die Firma Easywind aus Nordfriesland vertreibt eine zertifizierte und sturmfeste Kleinwindanlage. Mehr als 300 Anlagen sind bereits verkauft. In Deutschland decken vor allem Landwirte und kleine Betriebe so ihren Bedarf.

  16. Incorporating Wind Generation in Cap and Trade Programs

    Energy Technology Data Exchange (ETDEWEB)

    Bluestein, J.; Salerno, E.; Bird, L.; Vimmerstedt, L.

    2006-07-01

    Cap and trade programs are increasingly being used to reduce emissions from electricity generation in the United States. Cap and trade programs primarily target emitting generators, but programs have also included renewable generators, such as wind generators. States cite several reasons why they have considered the policy option of including renewable generators in cap and trade programs: to provide an incentive for lower-emitting generation, to achieve emissions reductions in non-capped pollutants, and to gain local economic benefits associated with renewable energy projects. The U.S. Environmental Protection Agency also notes these rationales for considering this policy alternative, and the National Association of Regulatory Commissioners (NARUC) passed a resolution supporting the inclusion of renewable energy in cap and trade programs. This report explores why states consider this policy option, what participation could mean for wind generators, and how wind generation can most effectively be included in state, federal, and regional cap and trade programs.

  17. Toward improved statistical treatments of wind power forecast errors

    Science.gov (United States)

    Hart, E.; Jacobson, M. Z.

    2011-12-01

    The ability of renewable resources to reliably supply electric power demand is of considerable interest in the context of growing renewable portfolio standards and the potential for future carbon markets. Toward this end, a number of probabilistic models have been applied to the problem of grid integration of intermittent renewables, such as wind power. Most of these models rely on simple Markov or autoregressive models of wind forecast errors. While these models generally capture the bulk statistics of wind forecast errors, they often fail to reproduce accurate ramp rate distributions and do not accurately describe extreme forecast error events, both of which are of considerable interest to those seeking to comment on system reliability. The problem often lies in characterizing and reproducing not only the magnitude of wind forecast errors, but also the timing or phase errors (ie. when a front passes over a wind farm). Here we compare time series wind power data produced using different forecast error models to determine the best approach for capturing errors in both magnitude and phase. Additionally, new metrics are presented to characterize forecast quality with respect to both considerations.

  18. 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)

  19. Wind and tornado guidelines

    International Nuclear Information System (INIS)

    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

  20. Wind energy in Europe

    International Nuclear Information System (INIS)

    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

  1. Wind power barometer

    International Nuclear Information System (INIS)

    Wind power makes further inroads into the world's electricity mix every year. It looks as though global wind power capacity will increase by another 44184 MW in 2012 (it means a 18% increase), and so raise global installed capacity to more than 281 GW. The growth of the total wind power capacity in European Union reached 12.3% in 2012 which corresponds to a supplementary wind power capacity of 11.84 GW. The growth in 2012 was driven by the United-States which chalked up a new installation record, and by Europe which remains a safe bet in the world market. The Asian market weakened a little but its potential for this year nonetheless looks bright. In 2012, Asia is still the main installation area for wind power with a 35.6% market share.The electricity production from wind power in the European Union was 178,93 TWh in 2011 and 200.16 TWh in 2012 and in 2012 Spain was the top European wind power producer with an output of 48.5 TWh followed by Germany with 46 TWh, United-Kingdom with 21 TWh, France with 14.9 TWh and Italy with 13.2 TWh

  2. Wind power utilization guide

    Science.gov (United States)

    Pal, D.

    1981-09-01

    This report presents general information covering site wind potential and characteristics, specific design, system design, and siting requirements for utilization of wind energy conversion systems (WECS) at Navy installations. The objective of this report is also to provide a method for performing economic analysis to plan and justify a WECS in a particular Navy application. The information presented here is sufficient to enable an engineer to prepare a system's design to conduct a feasibility study for a given application of WECS. Most Navy applications of wind power will involve generation of electricity using small wind turbine generators (less than 60 kW size), with or without storage, located at remote Navy sites. Larger (over 100 kW size) WECS will, generally, be integrated with a base grid located on remote overseas or CONUS bases. This report, however, deals only with guidance for applying small WECS at Navy installations. The subject matter is divided into five parts dealing respectively with wind behavior and its determination with wind-driven turbines, power conditioning requirements, siting requirements, and the economics of wind power under different conditions. Three examples are given to demonstrate use of these sections in developing the required feasibility or design information for a given application.

  3. Betting on wind energy

    International Nuclear Information System (INIS)

    In the first part of this study, the authors try to identify whether the economical and environmental context is adapted to the wind energy development. In order to do so, they discuss wind energy as a possible answer to climate emergency, critics formulated against wind energy, the effects of the financial crisis and the opportunities offered by wind energy within this crisis. In the second part, they discuss the French context and the debates on wind energy, highlighting the importance of some parameters in the cost analysis of wind turbine, presenting the results of a sensitivity analysis, and highlighting the importance of the over-cost calculation. They assess the current development status of the French wind energy industry and underline the opportunities for the future. In the third part, they describe the development status, lever and perspectives in different countries: Germany where the development of this sector has been successful, China which is becoming a major actor, the United States which are displaying the highest growth in this area, and Denmark which is the world leader

  4. Wind energy potential in Bulgaria

    International Nuclear Information System (INIS)

    In this study, wind characteristic and wind energy potential in Bulgaria were analyzed using the wind speed data. The wind energy potential at different sites in Bulgaria has been investigated by compiling data from different sources and analyzing it using a software tool. The wind speed distribution curves were obtained by using the Weibull and Rayleigh probability density functions. The results relating to wind energy potential are given in terms of the monthly average wind speed, wind speed probability density function (PDF), wind speed cumulative density function (CDF), and wind speed duration curve. A technical and economic assessment has been made of electricity generation from three wind turbines having capacity of (60, 200, and 500 kW). The yearly energy output capacity factor and the electrical energy cost of kWh produced by the three different turbines were calculated

  5. 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…

  6. Marine wind data presentation using wind transition matrix

    Digital Repository Service at National Institute of Oceanography (India)

    Mascarenhas, A.J.; Gouveia, A.D.; Desai, R.G.P.

    One of the methods to simulate the random wind behaviour through time is to use historical wind data presented in the form of wind transition matrix. Here it is assumed that, the probability that the wind will shift from one direction to another...

  7. 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

    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...

  8. Regional wind energy assessment program progress report, October 1980-September 1981. Appendix. Wind statistics summaries

    Energy Technology Data Exchange (ETDEWEB)

    Baker, R W; Wade, J E; Persson, P O.G.; Armstrong, B

    1981-12-01

    The wind statistics summarized include monthly wind speed and spectrum analyzer summaries, diurnal wind speed tables, high wind summaries (greater than or equal to 50 mph), wind rose tables, and wind speed and direction frequency distributions. (LEW)

  9. Quantifying the Geographic Diversity Needed to Reduce Wind Power Variability

    Science.gov (United States)

    St Martin, C.; Handschy, M.; Lundquist, J. K.

    2014-12-01

    The variability in wind-generated electricity complicates its integration into the electrical grid at higher penetrations. This variability can be reduced by interconnecting wind farms across large regions. We investigate the effectiveness of this aggregation with two extensive data sets. The first consists of 44 years of hourly 10-m wind speeds from 117 stations spanning distances of 5000 km across Canada from the National Climate Data Archive of Environment Canada. The second dataset consists of four years of 5-minute averaged wind speeds from stations across 350 km of the northwestern US from the Bonneville Power Administration. This study seeks to quantify how time scale affects the drop-off of correlation with distance, and hence statistical independence and the degree of geographic diversity needed to provide smoothing on various time scales. To eliminate non-stationarities, we filter both datasets to remove diurnal cycles and seasonal trends, after which we digitally high-pass filter the data on 0.25-2000 hour timescales relevant to power grid management. The wind speed data are then correlated between stations for each high-pass filter cut-off. In both datasets, the correlations between stations fall to zero with increasing station separation distance. Differences in inter-station azimuthal bearing account for a small but distinct fraction of the wide scatter in correlation vs. distance for the Canadian data set, with stations separated along a line 10° North of East-West being systematically less correlated than those perpendicular to that line. Similarities between these two datasets reveal behavior that, if universal, could be particularly useful for grid management. Both datasets exhibit a correlation length that varies as l = l0(1+25/T)-2, where l0 is the correlation length without high-pass filtering and T is the high-pass cut-off (in hours). Since the inter-site separation needed for statistical independence falls for time scales shorter than 25

  10. Airborne wind energy

    CERN Document Server

    Ahrens, Uwe; Schmehl, Roland

    2013-01-01

    This reference offers an overview of the field of airborne wind energy. As the first book of its kind, it provides a consistent compilation of the fundamental theories, a compendium of current research and development activities as well as economic and regulatory aspects. In five parts, the book demonstrates the relevance of Airborne Wind Energy and the role that this emerging field of technology can play for the transition towards a renewable energy economy. Part I on 'Fundamentals' contains seven general chapters explaining the principles of airborne wind energy and its different variants, o

  11. Extreme winds in Denmark

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-02-01

    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 terrain with the roughness length 0.05 m. The sites are, from west, Skjern (15 years), Kegnaes (7 years), Sprogoe (20 years), and Tystofte (15 years). The data are ten minute averages of wind speed, wind direction, temperature and pressure. The last two quantities are used to determine the air density {rho}. The data are cleaned for terrain effects by means of a slightly modified WASP technique where the sector speed-up factors and roughness lengths are linearly smoothed with a direction resolution of one degree. Assuming geotropic balance, all the wind-velocity data are transformed to friction velocity u{sub *} and direction at standard conditions by means of the geotropic drag law for neutral stratification. The basic wind velocity in 30 deg. sectors are obtained through ranking of the largest values of the friction velocity pressure 1/2{rho}u{sub *}{sup 2} taken both one every two months and once every year. The main conclusion is that the basic wind velocity is significantly larger at Skjern, close to the west coast of Jutland, than at any of the other sites. Irrespective of direction, the present standard estimates of 50-year wind are 25 {+-} 1 m/s at Skern and 22 {+-} 1 m/s at the other three sites. These results are in agreement with those obtained by Jensen and Franck (1970) and Abild (1994) and supports the conclusion that the wind climate at the west coast of Jutland is more extreme than in any other part of the country. Simple procedures to translate in a particular direction sector the standard basic wind velocity to conditions with a different roughness length and height are presented. It is shown that a simple scheme makes it possible to calculate the total 50-year extreme load on a general structure without

  12. Wind farm design optimization

    Energy Technology Data Exchange (ETDEWEB)

    Carreau, Michel; Morgenroth, Michael; Belashov, Oleg; Mdimagh, Asma; Hertz, Alain; Marcotte, Odile

    2010-09-15

    Innovative numerical computer tools have been developed to streamline the estimation, the design process and to optimize the Wind Farm Design with respect to the overall return on investment. The optimization engine can find the collector system layout automatically which provide a powerful tool to quickly study various alternative taking into account more precisely various constraints or factors that previously would have been too costly to analyze in details with precision. Our Wind Farm Tools have evolved through numerous projects and created value for our clients yielding Wind Farm projects with projected higher returns.

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

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, L.M.; Garcia, C.A.; Saenz, J.R. [Department of Electrical Engineering, EPS Algeciras, University of Cadiz, Avda. Ramon Puyol, s/n. 11202 Algeciras, Cadiz (Spain); Jurado, F. [Department of Electrical Engineering, EPS Linares, University of Jaen, C/ Alfonso X, n 28. 23700 Linares, Jaen (Spain)

    2009-03-15

    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. (author)

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

    International Nuclear Information System (INIS)

    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

  15. Risk-based scheduling of multiple search passes for UUVs

    Science.gov (United States)

    Baylog, John G.; Wettergren, Thomas A.

    2016-05-01

    This paper addresses selected computational aspects of collaborative search planning when multiple search agents seek to find hidden objects (i.e. mines) in operating environments where the detection process is prone to false alarms. A Receiver Operator Characteristic (ROC) analysis is applied to construct a Bayesian cost objective function that weighs and combines missed detection and false alarm probabilities. It is shown that for fixed ROC operating points and a validation criterion consisting of a prerequisite number of detection outcomes, an interval exists in the number of conducted search passes over which the risk objective function is supermodular. We show that this property is not retained beyond validation criterion boundaries. We investigate the use of greedy algorithms for distributing search effort and, in particular, examine the double greedy algorithm for its applicability under conditions of varying criteria. Numerical results are provided to demonstrate the effectiveness of the approach.

  16. Approximate Message Passing with Restricted Boltzmann Machine Priors

    CERN Document Server

    Tramel, Eric W; Krzakala, Florent

    2015-01-01

    Approximate Message Passing (AMP) has been shown to be an excellent statistical approach to signal inference and compressed sensing problem. The AMP framework provides modularity in the choice of signal prior; here we propose a hierarchical form of the Gauss-Bernouilli prior which utilizes a Restricted Boltzmann Machine (RBM) trained on the signal support to push reconstruction performance beyond that of simple iid priors for signals whose support can be well represented by a trained binary RBM. We present and analyze two methods of RBM factorization and demonstrate how these affect signal reconstruction performance within our proposed algorithm. Finally, using the MNIST handwritten digit dataset, we show experimentally that using an RBM allows AMP to approach oracle-support performance.

  17. Supporting the Development of Resilient Message Passing Applications using Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Naughton, III, Thomas J [ORNL; Engelmann, Christian [ORNL; Vallee, Geoffroy R [ORNL; Boehm, Swen [ORNL

    2014-01-01

    An emerging aspect of high-performance computing (HPC) hardware/software co-design is investigating performance under failure. The work in this paper extends the Extreme-scale Simulator (xSim), which was designed for evaluating the performance of message passing interface (MPI) applications on future HPC architectures, with fault-tolerant MPI extensions proposed by the MPI Fault Tolerance Working Group. xSim permits running MPI applications with millions of concurrent MPI ranks, while observing application performance in a simulated extreme-scale system using a lightweight parallel discrete event simulation. The newly added features offer user-level failure mitigation (ULFM) extensions at the simulated MPI layer to support algorithm-based fault tolerance (ABFT). The presented solution permits investigating performance under failure and failure handling of ABFT solutions. The newly enhanced xSim is the very first performance tool that supports ULFM and ABFT.

  18. A second pass gated reconstruction scheme with conjugate weights

    Science.gov (United States)

    Erhard, Klaus; Grass, Michael

    2009-02-01

    Rotational X-ray data acquisition in combination with gated reconstruction is applied most commonly to reconstruct 3D or 4D images of the heart on interventional X-ray systems. The data are acquired during breath hold and with intravenous contrast agent injection. Unfortunately, when using a single circular arc acquisition with parallel ECG recording, the gating of the projections leads to under-sampling artifacts in the reconstruction volume. In this contribution an artifact reduction method is suggested which is based on an initial gated reconstruction of a cardiac volume at limited quality, the subsequent segmentation of the volume and a second pass correction to enhance the signal-to-noise ratio in the reconstruction volume and to reduce the artifacts due to gating. The method is applied to both phantom and animal data.

  19. Le présent du passé

    OpenAIRE

    Gourievidis, Laurence

    2009-01-01

    Les lieux de mémoire de l’île de Lewis dans les Hébrides ont longtemps reflété un passé lointain : le site mégalithique de Callanish, la tour défensive (broch) de Carloway datant de l’âge de fer ou encore les figurines de l’échiquier médiéval trouvées sur l’île en 1831. La visite du musée de Stornoway – capitale de l’île et des Hébrides extérieures – confirme amplement cette image. Cependant, depuis les années 1990, l’île voit une efflorescence de monuments dédiés à des événements beaucoup pl...

  20. First-pass radionuclide ventriculography in conscious dogs

    International Nuclear Information System (INIS)

    Six trained chronically instrumented, conscious dogs were used to study the function of the left ventricle by first-past radionuclide ventriculography (RNV). The body position had effect on left ventricular end-diastolic and stroke volumes, whereas ejection fraction remained unchanged. In comparison of the two injection volumes a minor difference was found in left atrial emptying, while the differences in left ventricular function were non-significant. In spite of training and careful standardization of experimental procedures, relatively high individual variation between animals was found in most parameters studied. The first-pass RNV method proved to be promising for measuring the left ventricular function in conscious dogs. Although the left atrium has reflectory tachycardic potential to distension, the volumes used for RNV did not affect the results. The left ventricular adaptation to head-up tilting in conscious dogs seems to consist mainly of decrease in left ventricular volume without significant effect on ejection fraction. (author)

  1. Diffraction of terahertz waves after passing through a Fresnel lens

    International Nuclear Information System (INIS)

    The spatiotemporal and spectral characteristics of ultrawide-band terahertz pulses after passing through a Fresnel lens are studied by using the scalar diffraction theory. The simulation shows that the transmitted terahertz waveforms compress with increasing propagation distance, and the multi-frequency focusing phenomenon at different focal points is observed. Additionally, the distribution of terahertz fields in a plane perpendicular to the axis is also discussed, and it is found that the diffraction not only induces focusing on-axis but also inhibits focusing at off-axis positions. Therefore, the Fresnel lens may be a useful alternative approach to being a terahertz filter. Moreover, the terahertz pulses travelling as a basic mode of a Gaussian beam are discussed in detail. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  2. IMP: A Message-Passing Algorithmfor Matrix Completion

    CERN Document Server

    Kim, Byung-Hak; Pfister, Henry D

    2010-01-01

    A new message-passing (MP) method is considered for the matrix completion problem associated with recommender systems. We attack the problem using a (generative) factor graph model that is related to a probabilistic low-rank matrix factorization. Based on the model, we propose a new algorithm, termed IMP, for the recovery of a data matrix from incomplete observations. The algorithm is based on a clustering followed by inference via MP (IMP). The algorithm is compared with a number of other matrix completion algorithms on real collaborative filtering (e.g., Netflix) data matrices. Our results show that, while many methods perform similarly with a large number of revealed entries, the IMP algorithm outperforms all others when the fraction of observed entries is small. This is helpful because it reduces the well-known cold-start problem associated with collaborative filtering (CF) systems in practice.

  3. DFB fiber laser hydrophone with band-pass response.

    Science.gov (United States)

    Zhang, Faxiang; Zhang, Wentao; Li, Fang; Liu, Yuliang

    2011-11-15

    A distributed-feedback fiber laser hydrophone with band-pass response is presented. The design of the hydrophone aims to equalize static pressure and eliminate signal aliasing of high-frequency acoustic components. Theoretical analysis is presented based on electro-acoustic theory. The experimental results agree well with the theory. The measured underwater responses show that the hydrophone has a pressure sensitivity of -170 dB re:pm/μPa over a bandwidth between 100 Hz and 500 Hz. A sensitivity reduction exceeding -35 dB is observed at 2500 Hz. The tested static pressure sensitivity of the hydrophone is -226 dB. The proposed fiber laser hydrophone of this kind is expected to have important application in deep water fiber-optic sonar systems with anti-aliasing, and the understanding gained through this work can be extended to a guide of hydrophone design for required filtering bandwidth. PMID:22089550

  4. Neutron spin rotation in passing through center-asymmetric monocrystal

    International Nuclear Information System (INIS)

    One observed the effect of cold neutron spin rotation when passing through center-asymmetric single crystal. The effect is caused by the Schwinger interaction of magnetic moment of a moving neutron with intracrystalline electric field of center-asymmetric crystal and depends on the direction of neutron propagation thorough the crystal on its energy. The typical value of the effect for α-quartz is shown to constitute ≅ (1-2) x 10-4 rad/cm within wave length wide range (ranging from 2.8 A up to 5.5 A) and to be governed by the degree of beam monochromatism (Δλ/λ = (2-5) x 10-2 here). This effect value corresponds to ≅ (0.5-1) x 105 V/cm electric field affecting a neutron. The measured value is in good conformity with the theoretical calculation

  5. Wind Energy Program: Top 10 Program Accomplishments

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-01-18

    Brochure on the top accomplishments of the Wind Energy Program, including the development of large wind machines, small machines for the residential market, wind tunnel testing, computer codes for modeling wind systems, high definition wind maps, and successful collaborations.

  6. 3D characterization of the Astor Pass geothermal system, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Mayhew, Brett [NBMG; Faulds, James E

    2013-10-19

    The Astor Pass geothermal system resides in the northwestern part of the Pyramid Lake Paiute Reservation, on the margins of the Basin and Range and Walker Lane tectonic provinces in northwestern Nevada. Seismic reflection interpretation, detailed analysis of well cuttings, stress field analysis, and construction of a 3D geologic model have been used in the characterization of the stratigraphic and structural framework of the geothermal area. The area is primarily comprised of middle Miocene Pyramid sequence volcanic and sedimentary rocks, nonconformably overlying Mesozoic metamorphic and granitic rocks. Wells drilled at Astor Pass show a ~1 km thick section of highly transmissive Miocene volcanic reservoir with temperatures of ~95°C. Seismic reflection interpretation confirms a high fault density in the geothermal area, with many possible fluid pathways penetrating into the relatively impermeable Mesozoic basement. Stress field analysis using borehole breakout data reveals a complex transtensional faulting regime with a regionally consistent west-northwest-trending least principal stress direction. Considering possible strike-slip and normal stress regimes, the stress data were utilized in a slip and dilation tendency analysis of the fault model, which suggests two promising fault areas controlling upwelling geothermal fluids. Both of these fault intersection areas show positive attributes for controlling geothermal fluids, but hydrologic tests show the ~1 km thick volcanic section is highly transmissive. Thus, focused upwellings along discrete fault conduits may be confined to the Mesozoic basement before fluids diffuse into the Miocene volcanic reservoir above. This large diffuse reservoir in the faulted Miocene volcanic rocks is capable of sustaining high pump rates. Understanding this type of system may be helpful in examining large, permeable reservoirs in deep sedimentary basins of the eastern Basin and Range and the highly fractured volcanic geothermal

  7. Parallelization of a hydrological model using the message passing interface

    Science.gov (United States)

    Wu, Yiping; Li, Tiejian; Sun, Liqun; Chen, Ji

    2013-01-01

    With the increasing knowledge about the natural processes, hydrological models such as the Soil and Water Assessment Tool (SWAT) are becoming larger and more complex with increasing computation time. Additionally, other procedures such as model calibration, which may require thousands of model iterations, can increase running time and thus further reduce rapid modeling and analysis. Using the widely-applied SWAT as an example, this study demonstrates how to parallelize a serial hydrological model in a Windows® environment using a parallel programing technology—Message Passing Interface (MPI). With a case study, we derived the optimal values for the two parameters (the number of processes and the corresponding percentage of work to be distributed to the master process) of the parallel SWAT (P-SWAT) on an ordinary personal computer and a work station. Our study indicates that model execution time can be reduced by 42%–70% (or a speedup of 1.74–3.36) using multiple processes (two to five) with a proper task-distribution scheme (between the master and slave processes). Although the computation time cost becomes lower with an increasing number of processes (from two to five), this enhancement becomes less due to the accompanied increase in demand for message passing procedures between the master and all slave processes. Our case study demonstrates that the P-SWAT with a five-process run may reach the maximum speedup, and the performance can be quite stable (fairly independent of a project size). Overall, the P-SWAT can help reduce the computation time substantially for an individual model run, manual and automatic calibration procedures, and optimization of best management practices. In particular, the parallelization method we used and the scheme for deriving the optimal parameters in this study can be valuable and easily applied to other hydrological or environmental models.

  8. Effect of skin-pass rolling direction on magnetic properties of semiprocessed nonoriented electrical steel sheets

    Energy Technology Data Exchange (ETDEWEB)

    Kurosaki, Y.; Shimazu, T.; Shiozaki, M.

    1999-09-01

    Effect of skin-pass rolling direction on magnetic properties and directionality in semiprocessed nonoriented electrical steel sheets produced by skin-pass rolling process was studied. Skin-pass rolling direction greatly affects magnetic properties and directionality. By control of skin-pass rolling direction, the value of B{sub 50} in the required directions such as 0{degree}, 90{degree} and circumferential direction can be adjusted and the value of B{sub 50} is higher than that of the usual skin-pass rolling direction of 0{degree}. The textures of the steel sheets developed after batch annealing varied with the skin-pass rolling directions and this result indicates that the residual strain energy by skin-pass rolling varies with skin-pass rolling directions.

  9. Wind characteristics and available wind energy in Egypt

    International Nuclear Information System (INIS)

    Three sites in Egypt, differing in natural conditions but having almost the same wind characteristics are chosen for this study. Annual mean wind speed at a height of 20m above ground level ranges between 4.6 and 5.5 m/s. Daily wind-speed distribution for every month of the year is presented. Monthly average wind speeds throughout the year are also presented. The analysis shows that the yearly average of the available wind power ranges between 73 and 112 W/m2. In view of wind energy exploration for agricultural purposes, estimates are reported of the seasonal and annual duration of wind speed and of duration of the available wind power. The possibility of utilizing wind energy at the different sites using small scale wind energy conversion systems is discussed. (author)

  10. Estimation of System Balancing Requirements due to the Integration of Large-Scale Wind Energy

    International Nuclear Information System (INIS)

    This work presents a new method for developing realistic time-series of aggregated wind energy production and forecasts for system integration studies. To this end, simultaneous wind speed time series at planned wind farm locations are needed. Temporal and spatial correlations must be taken into account to make a realistic assessment of system-wide properties, such as variability and predictability in large-scale wind production. Offshore wind growth scenarios are developed, consistent with the renewable policy goals in the Netherlands over the next 15 years. We use one-year worth of 10-minute averaged wind speeds measured at several on- and offshore locations. The measurements are first transformed from sensor height to hub height. Average wind patterns are estimated and multi-variate normal theory is used to express the covariance between locations as a function of distance. The wind speed data is interpolated at the farm locations and finally averaged over 15 minutes, the market resolution interval for the Dutch balancing market. Based on the program AVDE, which employs data from the atmospheric model HIRLAM, we create day-ahead 15-minute wind speed forecasts for a subset of the locations where measurements were available. Again using multivariate normal theory, appropriately correlated forecast errors are created for the planned locations. Both actual and forecasted wind speeds are passed through a multi-turbine power curve, and summed up to create two nationwide aggregated time series of actual and forecasted wind power. Two insights are derived from the developed data set: the degree of long-term variability and the degree of predictability in the nation-wide wind energy production, for a given scenario. For 7.8 GW installed wind power, the imbalance energy requirements due to wind variations across 15-minute intervals is plus/minus 10%, while the requirements due to forecast errors vary between 45% for down regulation and 50% for up regulation.

  11. Wind power plant potentials in Ghana

    OpenAIRE

    Safo, Prince

    2013-01-01

    This thesis studies the wind energy technology and the wind technology transfer to Ghana. The thesis analyses some market achievements of wind energy in the world, types and components of the wind energy technology, cooperation involved in manufacturing of the component of the wind turbine, best areas for wind turbine, types of the wind energy construction, applications of wind energy, arrangement of wind farm, environmental impact of the technology and assessment of wind energy resources in ...

  12. Who can replace Xavi? A passing motif analysis of football players

    OpenAIRE

    Peña, Javier López; Navarro, Raúl Sánchez

    2015-01-01

    Traditionally, most of football statistical and media coverage has been focused almost exclusively on goals and (ocassionally) shots. However, most of the duration of a football game is spent away from the boxes, passing the ball around. The way teams pass the ball around is the most characteristic measurement of what a team's "unique style" is. In the present work we analyse passing sequences at the player level, using the different passing frequencies as a "digital fingerprint" of a player'...

  13. From local wind energy resource to national wind power production

    OpenAIRE

    Wolf-Gerrit Früh

    2015-01-01

    Wind power is one of the most established renewable power resources yet it is also one of the most volatile resources. This poses a key challenge for successfully integrating wind power at a large scale into the power grid. Here we present an analysis of the time scales associated with wind power from hourly to seasonal fluctuations and how combining spatially distributed wind power sources helps to reduce its volatility. The analysis, based on observed wind speeds, is then generalised in a s...

  14. 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)

  15. LARGE SCALE WIND CLIMATOLOGICAL EXAMINATIONS OF WIND ENERGY UTILIZATION

    OpenAIRE

    ANDREA KIRCSI

    2008-01-01

    The aim of this article is to describe the particular field of climatology which analyzes air movement characteristics regarding utilization of wind for energy generation. The article describes features of wind energy potential available in Hungary compared to wind conditions in other areas of the northern quarter sphere in order to assist the wind energy use development in Hungary. Information on wind climate gives a solid basis for financial and economic decisions of stakeholders in the fie...

  16. 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...

  17. Danish Wind Power

    DEFF Research Database (Denmark)

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

    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...... 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...... 2004-2008, such subsidy has increased consumer prices by 0.54 €¢/kWh on average. On the other hand, however, the same electricity consumers also benefitted from the wind turbines since the wind power decreased the electricity market price on Nord Pool. On average during 2004-2008, such effect decreased...

  18. Wind Measurement LIDAR Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Systems & Processes Engineering Corporation (SPEC) proposes a Wind Measurement LIDAR whose sensor assembly is composed of SPEC Gen IV LIDAR seeker, with 12.8...

  19. Waves in pulsar winds

    CERN Document Server

    Kirk, J G

    2010-01-01

    The radio, optical, X-ray and gamma-ray nebulae that surround many pulsars are thought to arise from synchrotron and inverse Compton emission. The energy powering this emission, as well as the magnetic fields and relativistic particles, are supplied by a "wind" driven by the central object. The inner parts of the wind can be described using the equations of MHD, but these break down in the outer parts, when the density of charge carriers drops below a critical value. This paper reviews the wave properties of the inner part (striped wind), and uses a relativistic two-fluid model (cold electrons and positrons) to re-examine the nonlinear electromagnetic modes that propagate in the outer parts. It is shown that in a radial wind, two solutions exist for circularly polarised electromagnetic modes. At large distances one of them turns into a freely expanding flow containing a vacuum wave, whereas the other decelerates, corresponding to a confined flow.

  20. Noise from wind turbines

    International Nuclear Information System (INIS)

    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)

  1. 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...

  2. Wind for energy

    International Nuclear Information System (INIS)

    This International Solar Energy Society, (ISES), publication, with the aid of interesting graphics and photos, illustrates how energy can be harnessed from the wind and how this energy can effectively be applied. With reference to the Italian context, the book contains an assessment of available resources, feasible sites, wind energy research programs, national financial and legal incentives. Outlines are made of the essential equipment in terms of wind turbines and power conversion systems; wind farm economics; environmental impacts (e.g., visual impact, noise pollution, interaction with wildlife, electromagnetic interference, etc.); and safety and reliability requirements. Overviews are given of the world marketing situation relevant to this technology, and the major research programs being conducted world-wide

  3. 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.

  4. Moriah Wind System Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose: The Moriah Wind System Laboratory provides in-service support for the more than 50 U.S. Navy, U.S. Coast Guard and Military Sealift Command ships on which...

  5. NOAA NDBC SOS - winds

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NDBC SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have winds data. Because of the nature of SOS requests, requests for data...

  6. 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.

  7. Superconducting Wind Turbine Generators

    DEFF Research Database (Denmark)

    Mijatovic, Nenad

    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 from a......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 in the future. The work presented 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 design and constructed a HTS machine experimental...

  8. Superconducting wind turbine generators

    DEFF Research Database (Denmark)

    Mijatovic, Nenad

    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 an......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 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...

  9. Extreme winds in Denmark

    DEFF Research Database (Denmark)

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

    1999-01-01

    are, from west, Skjern (15 years), Kegnæs (7 years), Sprogø (20 years), and Tystofte (15 years). The data are ten minute averages of wind speed, wind direction, temperature and pressure. The last two quantitiesare used to determine the air density ¤#rho#¤ . The data are cleaned for terrain effects by...... means of the geostrophic drag law for neutral stratification. The basic wind velocity in 30o sectors are obtainedthrough ranking of the largest values of the ¤friction velocity pressure¤ 1/2 ¤#rho#¤¤u¤"2_x taken both once every two months and once every year. The main conclusion is that the basic wind...

  10. 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

  11. Small Wind Energy Systems

    DEFF Research Database (Denmark)

    Simoes, Marcelo; Farret, Felix Alberto; Blaabjerg, Frede

    2015-01-01

    devices, and a centralized distribution control. In order to establish a small wind energy system it is important to observe the following: (i) Attending the energy requirements of the actual or future consumers; (ii) Establishing civil liabilities in case of accidents and financial losses due to shortage...... costs and guaranteeing an acceptable energy supply. This paper discuss how performance is affected by local conditions and random nature of the wind, power demand profiles, turbine related factors, and presents the technical issues for implementing a self-excited induction generator system, or a......The application of small wind turbines for residential and commercial applications depends on how a microgrid can operate in a suitable way. Because there is variable demand and a random nature of wind resources, it is usually necessary the installation of controllable end-use loads, storage...

  12. Wind turbine design

    International Nuclear Information System (INIS)

    Using wind energy to generate power has become an attractive and feasible possibility as a complement to the traditional power generation methods. This is mainly due to advances in aerodynamic analysis, development of new composite materials and the experience gained through innovative and pioneering designs. Wind energy is abundant and inexhaustible. Its use to generate power in remote areas of developing countries with less developed infrastructure could accelerate the modernisation of such regions. This paper attempts to give an overview of the technical aspects of wind turbine design and is meant for an audience new to the subject. It is not the purpose of this presentation to deal in detail with the technical aspects, but rather to highlight the salient aspects of the design. After a brief introduction, the topics covered are aerodynamics and aeroacoustics of wind turbines with a discussion of the structural dynamics and vibration engineering aspects. (author)

  13. Wind Tunnel Testing Facilities

    Data.gov (United States)

    Federal Laboratory Consortium — NASA Ames Research Center is pleased to offer the services of our premier wind tunnel facilities that have a broad range of proven testing capabilities to customers...

  14. 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.

  15. NEW WIND WAVE GROWTH RELATIONS

    Institute of Scientific and Technical Information of China (English)

    WU Shu-ping; HOU Yi-jun; YIN Bao-shu

    2004-01-01

    In the present paper combining the relationship between wave steepness and wave age with the significant wave energy balance equation for wind wave,a new wind wave growth relation is presented.Comparisons with the other existing wind wave growth relations show that the results in present paper accord better with the wind wave growth process.

  16. 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.

  17. 40 CFR 205.160-6 - Passing or failing under SEA.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Passing or failing under SEA. 205.160... failing under SEA. (a) A failing vehicle is one whose measured noise level is in excess of the applicable... vehicles is less than or equal to the number in Column A, the sample passes. (c) Pass or failure of an...

  18. 75 FR 62512 - Sabine Pass Liquefaction, LLC; Application for Long-Term Authorization To Export Liquefied...

    Science.gov (United States)

    2010-10-12

    ... Pass Liquefaction, LLC; Application for Long-Term Authorization To Export Liquefied Natural Gas AGENCY... September 7, 2010, by Sabine Pass Liquefaction, LLC (Sabine Pass), requesting long-term, multi-contract... the future develops, the capacity to import LNG and with which trade is not prohibited by U.S. law...

  19. 22 CFR 9b.5 - Temporary Department of State press building passes.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Temporary Department of State press building passes. 9b.5 Section 9b.5 Foreign Relations DEPARTMENT OF STATE GENERAL REGULATIONS GOVERNING DEPARTMENT OF STATE PRESS BUILDING PASSES § 9b.5 Temporary Department of State press building passes. A media correspondent or technician who meets all...

  20. 9 CFR 310.6 - Carcasses and parts passed for cooking; marking.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Carcasses and parts passed for cooking... INSPECTION AND CERTIFICATION POST-MORTEM INSPECTION § 310.6 Carcasses and parts passed for cooking; marking. Carcasses and parts passed for cooking shall be marked conspicuously on the surface tissues thereof by...

  1. 9 CFR 312.3 - Official marks and devices to identify inspected and passed equine products.

    Science.gov (United States)

    2010-01-01

    ... inspected and passed equine products. 312.3 Section 312.3 Animals and Animal Products FOOD SAFETY AND... § 312.3 Official marks and devices to identify inspected and passed equine products. (a) The official... § 317.2 of this subchapter to identify inspected and passed mule and other (nonhorse) equine...

  2. Summertime wind climate in Yerevan: valley wind systems

    Science.gov (United States)

    Gevorgyan, Artur

    2016-05-01

    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.

  3. Renewable Energy Essentials: Wind

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    Subjects for further research, specific to wind energy technology, include more refined resource assessment; materials with higher strength to mass ratios; advanced grid integration and power quality and control technologies; standardisation and certification; development of low-wind regime turbines; improved forecasting; increased fatigue resistance of major components such as gearboxes; better models for aerodynamics and aeroelasticity; generators based on superconductor technology; deep-offshore foundations; and high-altitude 'kite' concepts.

  4. 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<

  5. 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...

  6. 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...

  7. Wind Energy Teachers Guide

    Energy Technology Data Exchange (ETDEWEB)

    anon.

    2003-01-01

    This guide, created by the American Wind Association, with support from the U.S. Department of Energy, is a learning tool about wind energy targeted toward grades K-12. The guide provides teacher information, ideas for sparking children's and students' interest, suggestions for activities to undertake in and outside the classroom, and research tools for both teachers and students. Also included is an additional resources section.

  8. Wind power for developing nations

    Science.gov (United States)

    Mikhail, A. S.

    1981-07-01

    The global potential of wind energy conversion systems (WECS) was assessed. The cost effectiveness of WECS depends on the availability of the wind resource, system power performance, and the comparative cost of alternative energy sources. An overview of the global wind resource including observed zonal wind systems for each continent, available wind data, current wind maps, and ongoing studies to assess the global wind potential are presented. A methodology to obtain a match between machine and site characteristics for most cost effective power production is outlined.

  9. Shearing Wind Helicity and Thermal Wind Helicity

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Helicity is defined as H=V.ω, where V and ω are the velocity and vorticity vectors, respectively.Many works have pointed out that the larger the helicity is, the longer the life cycle of the weather system is. However, the direct relationship of the helicity to the evolution of the weather system is not quite clear. In this paper, the concept of helicity is generalized as shearing wind helicity (SWH). Dynamically,it is found that the average SWH is directly related to the increase of the average cyclonic rotation of the weather system. Physically, it is also pointed out that the SWH, as a matter of fact, is the sum of the torsion terms and the divergence term in the vorticity equation. Thermal wind helicity (TWH), as a derivative of SWH, is also discussed here because it links the temperature field and the vertical wind field. These two quantities may be effective for diagnosing a weather system. This paper applies these two quantities in cylindrical coordinates to study the development of Hurricane Andrew to validate their practical use. Through analyzing the hurricane, it is found that TWH can well describe the characteristics of the hurricane such as the strong convection and release of latent heat. SWH is not only a good quantity for diagnosing the weather system, but also an effective one for diagnosing the development of the hurricane.

  10. The potential of wind farms

    International Nuclear Information System (INIS)

    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)

  11. Extreme winds in Denmark

    DEFF Research Database (Denmark)

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

    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 yr wind speed (10 min averages) under standard conditions, i.e., 10 m over a homogeneous terrain with the roughness length 0.05 m, The sites are Skjern (15 yr......): 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...

  12. 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.

  13. European wind turbine catalogue

    International Nuclear Information System (INIS)

    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. Wind turbines and health

    International Nuclear Information System (INIS)

    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.

  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. Linear wind generator

    International Nuclear Information System (INIS)

    The purpose of the linear wind-power generator described in this article is to decrease the following disadvantages of the common wind-powered turbine: 1) large bending and twisting moments to the blades and the shaft, especially when strong winds and turbulence exist; 2) significant values of the natural oscillation period of the construction result in the possibility of occurrence of destroying resonance oscillations; 3) high velocity of the peripheral parts of the rotor creating a danger for birds; 4) difficulties, connected with the installation and the operation on the mountain ridges and passages where the wind energy potential is the largest. The working surfaces of the generator in questions driven by the wind are not connected with a joint shaft but each moves along a railway track with few oscillations. So the sizes of each component are small and their number can be rather large. The mechanical trajectory is not a circle but a closed outline in a vertical plain, which consists of two rectilinear sectors, one above the other, connected in their ends by semi-circumferences. The mechanical energy of each component turns into electrical on the principle of the linear electrical generator. A regulation is provided when the direction of the wind is perpendicular to the route. A possibility of effectiveness is shown through aiming of additional quantities of air to the movable components by static barriers

  17. Wind power in Taiwan: Policy and development challenges

    International Nuclear Information System (INIS)

    The main aim of this paper is in discussing the outcome of the government's policies aimed at promoting the wind power industry. By analyzing the policies on renewable energy and the direct and indirect support mechanisms, the author reviews the achievements, limitations and strategies faced during their various stages. This research discovered that the series of measures adopted between 2000 and 2005 including installation plans, financial incentives, feed-in tariffs, export credit subsidies and R and D, helped to initiate the early steps of private investment, and allow domestic wind capacity to see stable growth. After 2005 with more clear goals set for wind energy installed capacity policies, R and D and industrial cooperation mechanisms, there was even greater breakthrough in limited market, enabling Taiwan's fledgling wind power industry to take its first steps onto the international production chain. In particular, the passing of the Renewable Energy Development Act in 2009 incited rapid growth in the domestic market as well as driving further development in the domestic wind energy industry. Overall, in current stage there is a need to get a handle on the gap still existing between international technology and market and that in Taiwan, in order to strategically develop a competitive advantage globally. - Highlights: → Taiwan wind power industries are still in the early forming stages.→ There are direct and indirect policy incentives for promoting the wind power.→ In the short term, R and D will focus on forecasting technology and on key components.→ In the mid-term, small to mid-scale wind power generators are appreciated.→ Currently, developing offshore WP, the MW WP turbine equipment is the key strategies.

  18. Wind power in Taiwan: Policy and development challenges

    Energy Technology Data Exchange (ETDEWEB)

    Liou, Hwa Meei, E-mail: liouhm@mail.ntust.edu.tw [Graduate Institute of Technology Management, National Taiwan University of Science and Technology, 43, Sec. 4, Keelung Rd., Taipei 106, Taiwan (China)

    2011-06-15

    The main aim of this paper is in discussing the outcome of the government's policies aimed at promoting the wind power industry. By analyzing the policies on renewable energy and the direct and indirect support mechanisms, the author reviews the achievements, limitations and strategies faced during their various stages. This research discovered that the series of measures adopted between 2000 and 2005 including installation plans, financial incentives, feed-in tariffs, export credit subsidies and R and D, helped to initiate the early steps of private investment, and allow domestic wind capacity to see stable growth. After 2005 with more clear goals set for wind energy installed capacity policies, R and D and industrial cooperation mechanisms, there was even greater breakthrough in limited market, enabling Taiwan's fledgling wind power industry to take its first steps onto the international production chain. In particular, the passing of the Renewable Energy Development Act in 2009 incited rapid growth in the domestic market as well as driving further development in the domestic wind energy industry. Overall, in current stage there is a need to get a handle on the gap still existing between international technology and market and that in Taiwan, in order to strategically develop a competitive advantage globally. - Highlights: > Taiwan wind power industries are still in the early forming stages.> There are direct and indirect policy incentives for promoting the wind power.> In the short term, R and D will focus on forecasting technology and on key components.> In the mid-term, small to mid-scale wind power generators are appreciated.> Currently, developing offshore WP, the MW WP turbine equipment is the key strategies.

  19. PREFACE: The Science of Making Torque from Wind 2012

    Science.gov (United States)

    2014-12-01

    The European Academy of Wind Energy (eawe) was pleased to announce its 4th scientific conference The Science of Making Torque from Wind. Predecessors have successfully been arranged in Delft, The Netherlands (2004), Lyngby, Denmark (2007) and Heraklion, Greece (2010). During the years the Torque Conference has established itself as Europe's leading scientific wind energy conference. The 2012 edition had been organized in the same tradition. More than 300 experts from academia and industry discussed the latest results and developments in fundamental and applied wind energy research, making this Science of Making Torque from Wind conference the largest one to that date. The seven keynote lectures provided the delegates with a unique overview on the state-of-the-art of science and technology. In over twenty sessions the participants discussed the most recent results in wind energy research. From numerical models to sophisticated experiments, from flow optimizations to structural designs, the numerous presentations covered a huge spectrum of ongoing scientific activities. The proceedings of the Torque 2012 combine the 110 papers that have passed the review process. We would like to thank all those who have been involved in organizing the conference and putting together these proceedings, including keynote speakers, session chairs and the enormous amount of reviewers involved. We are especially grateful to Gijs van Kuik for his untiring support. We also deeply appreciate the logistical support and technical services of the University of Oldenburg and the financial support of the State of Lower Saxony. At IOP we would like to thank Anete Ashton for her continuous encouraging support. We are looking forward to all future Torque Conferences, offering an excellent platform for the exchange of the latest and greatest scientific developments in the field of wind energy. Oldenburg, Germany, October 2014 Elke Seidel, Detlev Heinemann, Martin Kühn, Joachim Peinke and Stephan

  20. Afterglow Light Curves of Jetted Gamma-ray Burst Ejecta in Stellar Winds

    Institute of Scientific and Technical Information of China (English)

    Xue-Feng Wu; Zi-Gao Dai; Yong-Feng Huang; Hai-Tao Ma

    2004-01-01

    Optical and radio afterglows arising from shocks by relativistic conical ejecta running into pre-burst massive stellar winds are revisited. Under the homogeneous thin-shell approximation and a realistic treatment for the lateral expansion of jets, our results show that a notable break exists in the optical light curve in most cases we calculated in which the physical parameters are varied within reasonable ranges. For a relatively tenuous wind which cannot decelerate the relativistic jet to cause a light curve break within days, the wind termination shock due to the ram pressure of the surrounding medium occurs at a small radius, namely, a few times 1017 cm. In such a structured wind environment, the jet will pass through the wind within several hours and run into the outer uniform dense medium. The resulting optical light curve flattens with a shallower drop after the jet encounters the uniform medium, and then declines deeply, triggered by runaway lateral expansion.

  1. Tribological Aspects of the Process of Winding the Steel Rope Around the Winch Drum

    Directory of Open Access Journals (Sweden)

    M. Matejić, , , ,

    2014-03-01

    Full Text Available Proper winding of the steel rope around the winch drum is great importance, mostly for: prolonging the service life of the rope, reduction of deformations of the body and the sides of the drum if the winding of the rope is multilayered, increasing of the safety factors, easier unwinding of the rope while lowering the load, even running of the drive unit, etc. The focus of this paper is on the analysis of the friction which occurs in the process of winding and unwinding the rope around the winch drum. Friction force is in its highest intensity when the rope passes from one layer to another, if the winding of the rope is multilayered. As the result of the research, certain mechanisms of winding of the rope from the aspects of the friction force were obtained, and the effects of the forces on the sides of the drum were analyzed.

  2. Coastal Ohio Wind Project

    Energy Technology Data Exchange (ETDEWEB)

    Gorsevski, Peter; Afjeh, Abdollah; Jamali, Mohsin; Bingman, Verner

    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

  3. New Extended GeV Sources in the Galactic Plane Found in a Search of the Pass 8 Data from Fermi-LAT

    Science.gov (United States)

    Hays, Elizabeth A.; Cohen, Jamie; Grondin, Marie-Hélène; Lemoine-Goumard, Marianne; Fermi LAT Collaboration

    2016-01-01

    Spatially resolving pulsar wind nebulae (PWNe) and supernova remnants (SNRs) at GeV energies enables accurate representation of spectra, aids identification of multiwavelength counterparts, and probes possible substructure within the gamma-ray sources. Using 6 years of Fermi-LAT Pass 8 data above 10 GeV, we searched for spatially extended sources near the Galactic plane. The improved angular resolution and photon acceptance of the Pass 8 event reconstruction significantly aids in characterizing source extension and assessing spectral and morphological properties, a key consideration for studies of PWNe and SNRs in the gamma-ray band. Selecting photons above 10 GeV strikes a balance between keeping photon statistics high and diffuse gamma-ray emission low, and also carries benefits of a near constancy with energy of the point spread function of the LAT. More than 30 significantly extended sources are detected, many of which are resolved at GeV energies for the first time.

  4. Aquarius Scatterometer Winds

    Science.gov (United States)

    Yueh, S. H.; Fore, A.; Freedman, A. P.; Neumann, G.; Tang, W.; Brown, S.; Chaubell, M. J.; Jones, L.; Lagerloef, G. S.; LeVine, D.; Dinnat, E. P.; Meissner, T.; Wentz, F. J.; Vandemark, D. C.

    2011-12-01

    Aquarius is a combined passive/active L-band microwave instrument developed to map the salinity field at the surface of the ocean from space. The data will support studies of the coupling between ocean circulation, the global water cycle, and climate. The primary science objective of this mission is to monitor the seasonal and interannual variation of the large scale features of the surface salinity field in the open ocean with a spatial resolution of 150 km and a retrieval accuracy of 0.2 psu globally on a monthly basis. The measurement principle is based on the response of the L-band (1.413 GHz) sea surface brightness temperatures to sea surface salinity. To achieve the required 0.2 psu accuracy, the impact of sea surface roughness (e.g. wind-generated ripples and waves), along with several additional factors impacting the observed brightness temperature, must be corrected to better than a few tenths of a degree Kelvin. To this end, Aquarius includes a scatterometer to help correct for this surface roughness effect. The Aquarius/SACD was launched successfully on June 10, 2011, and the instrument is expected to be turned on in August. The prelaunch tests of Aquarius showed that the instrument should be extremely stable at the week-to-month time scale with drift of less than 0.1 K for the radiometer and 0.1 dB for the scatterometer. The current baseline algorithm for Aquarius is to use the scatterometer data in conjunction with the NCEP wind direction to derive the ocean surface wind speed and then a radiometer roughness correction. The pre-launch simulations predict 1 m/s wind speed accuracy. This will be tested using the Aquarius data collected in the coming few months. To quantify the benefits of combining passive and active microwave sensors for ocean salinity remote sensing, the Passive/Active L-band Sensor (PALS) was used to acquire data over a wide range of ocean surface wind conditions during the High Ocean Wind (HOW) Campaign in 2009. The PALS brightness

  5. Factors influencing wind energy curtailment

    OpenAIRE

    Burke, Daniel J.; O'MALLEY, MARK, J.

    2011-01-01

    Nonphysically firm wind generation connections (i.e., those to which curtailment can apply) may be necessary for significant wind integration to congested transmission networks. A study of factors influencing this associated wind energy curtailment is, therefore, of timely importance. In this paper, the wind curtailment estimation effects of natural inter-yearly wind profile variability, system demand-profile/fuel-price parameter uncertainty, and minimum system inertial constraints are studie...

  6. Uncertainty in wind energy forecasting

    OpenAIRE

    Moehrlen, Corinna

    2004-01-01

    Wind energy is the energy source that contributes most to the renewable energy mix of European countries. While there are good wind resources throughout Europe, the intermittency of the wind represents a major problem for the deployment of wind energy into the electricity networks. To ensure grid security a Transmission System Operator needs today for each kilowatt of wind energy either an equal amount of spinning reserve or a forecasting system that can predict the amount of energy that will...

  7. Performance of spanish wind turbines

    International Nuclear Information System (INIS)

    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)

  8. 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

  9. 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.

  10. 75 FR 47301 - Cedro Hill Wind LLC; Butler Ridge Wind Energy Center, LLC; High Majestic Wind Energy Center, LLC...

    Science.gov (United States)

    2010-08-05

    ...; EG10-36-000; EG10-37-000; EG10-38-000] Cedro Hill Wind LLC; Butler Ridge Wind Energy Center, LLC; High Majestic Wind Energy Center, LLC; Wessington Wind Energy Center, LLC; Juniper Canyon Wind Power LLC; Loraine Windpark Project, LLC; White Oak Energy LLC; Meadow Lake Wind Farm III LLC; Meadow Lake Wind...

  11. Operational effectiveness of passing zones depending on their length and traffic volume

    OpenAIRE

    Moreno Chou, Ana Tsui; Llorca Garcia, Carlos; García García, Alfredo; Pérez Zuriaga, Ana María

    2013-01-01

    Most studies on two-lane highway operations have focused on the percentage of following vehicles or the adjustment of the Highway Capacity Manual (HCM) procedure to local data. The HCM proposes the length of no-passing zones as a model parameter; however, the distribution and characteristics of passing zones are not addressed. In fact, only a few studies on the expected number of passes in a passing zone have been carried out. This research presents an analysis of the effectiveness of passing...

  12. Exchange Rate Pass-Through to Domestic Inflation in Hong Kong

    OpenAIRE

    Li-gang Liu; Andrew Tsang

    2008-01-01

    This paper estimates pass-through of exchange rate changes to domestic inflation in Hong Kong in a two-step approach. We first estimate exchange rate pass-through to import prices and then from import price to domestic inflation using a Phillips-Curve model. We find that Hong Kong¡¦s exchange rate pass-through to import prices is relatively high compared to the OECD average, although Hong Kong also witnessed a decline of pass-through after 1991. With respect to exchange rate pass-through to d...

  13. Interannual Variability of SST, SLA and Wind Waves in the Hawaii Area and Their Responses to ENSO

    Institute of Scientific and Technical Information of China (English)

    CHENG Yongcun; XU Qing; LIU Yuguang; LI Chongyin; RONG Zengzui; ZONG Haibo; XIU Peng; YIN Xiaobin

    2008-01-01

    Time series of sea surface temperature (SST),wind speed and significant wave height (SWH) from meteorologicalbuoys of the National Data Buoy Center (NDBC) are useful for studying the interannual variability and trend of these quantities at the buoy areas.The measurements from 4 buoys (B51001,B51002,B51003 and B51004) in the Hawaii area are used to study theresponses of the quantities to EI Nino and Southern Oscillation (ENSO).Long-term averages of these data reflect precise seasonaland climatological characteristics of SST,wind speed and SWH around the Hawaii area.Buoy observations from B51001 suggest asignificant warming trend which is,however,not very clear from the other three buoys.Compared with the variability of SST andSWH,the wind speeds from the buoy observations show an increasing trend.The impacts of El Nifio on SST and wind waves arealso shown.Sea level data observed by altimeter during October 1992 to September 2006 are analyzed to investigate the variabilityof sea level in the Hawaii area.The results also show an increasing trend in sea level anomaly (SLA).The low-passed SLA in theHawaii area is consistent with the inverse phase of the low-passed Sol (Southern Oscillation Index).Compared with the low-passedSOl and PDO (Pacific Decadal Oscillation),the low-passed PNA (Pacific-North America Index) has a better correlation with thelow-passed SLA in the Hawaii area.

  14. Dynamical downscaling of wind fields for wind power applications

    Science.gov (United States)

    Mengelkamp, H.-T.; Huneke, S.; Geyer, J.

    2010-09-01

    Dynamical downscaling of wind fields for wind power applications H.-T. Mengelkamp*,**, S. Huneke**, J, Geyer** *GKSS Research Center Geesthacht GmbH **anemos Gesellschaft für Umweltmeteorologie mbH Investments in wind power require information on the long-term mean wind potential and its temporal variations on daily to annual and decadal time scales. This information is rarely available at specific wind farm sites. Short-term on-site measurements usually are only performed over a 12 months period. These data have to be set into the long-term perspective through correlation to long-term consistent wind data sets. Preliminary wind information is often asked for to select favourable wind sites over regional and country wide scales. Lack of high-quality wind measurements at weather stations was the motivation to start high resolution wind field simulations The simulations are basically a refinement of global scale reanalysis data by means of high resolution simulations with an atmospheric mesoscale model using high-resolution terrain and land-use data. The 3-dimensional representation of the atmospheric state available every six hours at 2.5 degree resolution over the globe, known as NCAR/NCEP reanalysis data, forms the boundary conditions for continuous simulations with the non-hydrostatic atmospheric mesoscale model MM5. MM5 is nested in itself down to a horizontal resolution of 5 x 5 km². The simulation is performed for different European countries and covers the period 2000 to present and is continuously updated. Model variables are stored every 10 minutes for various heights. We have analysed the wind field primarily. The wind data set is consistent in space and time and provides information on the regional distribution of the long-term mean wind potential, the temporal variability of the wind potential, the vertical variation of the wind potential, and the temperature, and pressure distribution (air density). In the context of wind power these data are used

  15. 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)

  16. Characteristics for wind energy and wind turbines by considering vertical wind shear

    Institute of Scientific and Technical Information of China (English)

    郑玉巧; 赵荣珍

    2015-01-01

    The probability distributions of wind speeds and the availability of wind turbines were investigated by considering the vertical wind shear. Based on the wind speed data at the standard height observed at a wind farm, the power-law process was used to simulate the wind speeds at a hub height of 60 m. The Weibull and Rayleigh distributions were chosen to express the wind speeds at two different heights. The parameters in the model were estimated via the least square (LS) method and the maximum likelihood estimation (MLE) method, respectively. An adjusted MLE approach was also presented for parameter estimation. The main indices of wind energy characteristics were calculated based on observational wind speed data. A case study based on the data of Hexi area, Gansu Province of China was given. The results show that MLE method generally outperforms LS method for parameter estimation, and Weibull distribution is more appropriate to describe the wind speed at the hub height.

  17. [VARIANT ANATOMY OF SPLENIC LIGAMENTS AND ARTERIES PASSING THROUGH THEM].

    Science.gov (United States)

    Gaivoronskiy, I V; Kotiv, B N; Alekseyev, V S; Nichiporuk, G I

    2015-01-01

    The research was performed on 15 non embalmed bodies and 32 abdominal complexes of adult individuals. The comparative study of variant anatomy of splenic ligaments and architectonics of arteries passing through them was carried out to substantiate the mobilization of splenopancreatic complex. Anatomical and angiographic restudied were carried out using preparation, morphometry, injection of gastric, pancreatic and splenic vascular bed with red lead suspension. It was established that the form and sizes of splenic ligaments and their interrelation with the branches of the splenic artery were variable. The minimal and maximal sizes of gastrolienal, phrenicosplenic and splenocolic ligaments differed 2-3 times. In most cases, spleen was fixed in abdominal cavity by many short ligaments. It was shown that architectonics and topography of main branches of spleen artery were determined by morphometric characteristics of the spleen proper and its ligaments. The knowledge of splenic ligament variant anatomy allows a new perspective to approach to substantiate different methods of the mobilization of spleno-pancreatic complex during surgical operations on organs of the upper part of the peritoneal cavity and organ-preserving surgery of the spleen. PMID:26234038

  18. Single-pass memory system evaluation for multiprogramming workloads

    Science.gov (United States)

    Conte, Thomas M.; Hwu, Wen-Mei W.

    1990-01-01

    Modern memory systems are composed of levels of cache memories, a virtual memory system, and a backing store. Varying more than a few design parameters and measuring the performance of such systems has traditionally be constrained by the high cost of simulation. Models of cache performance recently introduced reduce the cost simulation but at the expense of accuracy of performance prediction. Stack-based methods predict performance accurately using one pass over the trace for all cache sizes, but these techniques have been limited to fully-associative organizations. This paper presents a stack-based method of evaluating the performance of cache memories using a recurrence/conflict model for the miss ratio. Unlike previous work, the performance of realistic cache designs, such as direct-mapped caches, are predicted by the method. The method also includes a new approach to the problem of the effects of multiprogramming. This new technique separates the characteristics of the individual program from that of the workload. The recurrence/conflict method is shown to be practical, general, and powerful by comparing its performance to that of a popular traditional cache simulator. The authors expect that the availability of such a tool will have a large impact on future architectural studies of memory systems.

  19. Single Pass Stripline Beam Position Monitor Design, Fabrication and Commissioning

    Science.gov (United States)

    Tan, Y.-R. E.; Wang, D.; Van Garderen, E.; McKinlay, J.

    2012-10-01

    To monitor the position of the electron beam during transport from the Booster Synchrotron to the Storage Ring at the Australian Synchrotron, a stripline Beam Position Monitor (BPM) has been designed, fabricated and installed in-house. The design was based on an existing stripline in the Booster and modified for the transfer line with a particular emphasis on ensuring the line impedance is properly matched to the detector system. The initial bench tests of a prototype stripline showed that the fabrication of the four individual striplines in the BPM was made precisely, each with a measured standing wave ratio (SWR) of 1.8 at 500 MHz. Further optimization for impedance matching will be done for new stripline BPMs. The linearity and gain factor was measured with the detector system. The detector system that digitizes the signals is an Instrumentation Technologies Brilliance Single Pass [1]. The results show an error of 1 mm at an offset (from the electrical centre) of 10 mm when a linear gain factor is assumed and an RMS noise of ~150 um that decreases to < 10 um with increasing signal intensity. The results were under our requirements for the transport line. The commissioning results of the stripline will also be presented showing a strong signal for an electron beam with an estimated integrated charge of ~50 nC with a position stability of 28 um (horizontal) and 75 um (vertical).

  20. 1 THz Micromachined Waveguide Band-Pass Filter

    Science.gov (United States)

    Liu, Shuang; Hu, Jiang; Zhang, Yong; Zheng, Zhongwan; Liu, Yupeng; Xu, Ruimin; Xue, Quan

    2016-05-01

    This paper presents a waveguide band-pass filter operating at the 0.75 ˜ 1.1 THz frequency band. The metal conductivity, the surface impedance, and the skin depth are investigated in the terahertz (THz) frequency band for more accurate designs, especially at the 1 THz and higher frequencies. Because the influence of the fabrication tolerance on the component performance cannot be negligible while the frequency increases, it is a necessary to adopt the simple structure with less resonant cavities for obtaining the given performance. Therefore, the filter in this paper is designed based on the TE301/TE102 dual-mode rectangular waveguide resonant cavities, which has fewer cavities and better rejection of the stop-band. The proposed filter is fabricated using the deep reactive ion etching (DRIE) micromachining technique. Measured results are in good agreement with simulations, which verifies the accuracy of the analysis above, and the design process is valuable to realize high-performance passive components while the frequency is up to 1 THz or higher frequencies.