WorldWideScience

Sample records for monthly gridded single

  1. CERES Monthly Gridded Single Satellite TOA and Surfaces/Clouds (SFC) data in HDF (CER_SFC_Terra-FM2-MODIS_Edition2B)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    The Monthly Gridded TOA/Surface Fluxes and Clouds (SFC) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SFC is also produced for combinations of scanner instruments. All instantaneous shortwave, longwave, and window fluxes at the Top-of-the-Atmosphere (TOA) and surface from the CERES SSF product for a month are sorted by 1-degree spatial regions and by the local hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the SFC along with other flux statistics and scene information. These average fluxes are given for both clear-sky and total-sky scenes. The regional cloud properties are column averaged and are included on the SFC. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2003-10-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=100] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

  2. CERES Monthly Gridded Single Satellite TOA and Surfaces/Clouds (SFC) data in HDF (CER_SFC_Terra-FM1-MODIS_Edition2A)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    The Monthly Gridded TOA/Surface Fluxes and Clouds (SFC) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SFC is also produced for combinations of scanner instruments. All instantaneous shortwave, longwave, and window fluxes at the Top-of-the-Atmosphere (TOA) and surface from the CERES SSF product for a month are sorted by 1-degree spatial regions and by the local hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the SFC along with other flux statistics and scene information. These average fluxes are given for both clear-sky and total-sky scenes. The regional cloud properties are column averaged and are included on the SFC. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2003-12-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=100] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

  3. CERES Monthly Gridded Single Satellite TOA and Surfaces/Clouds (SFC) data in HDF (CER_SFC_Terra-FM2-MODIS_Edition2C)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    The Monthly Gridded TOA/Surface Fluxes and Clouds (SFC) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SFC is also produced for combinations of scanner instruments. All instantaneous shortwave, longwave, and window fluxes at the Top-of-the-Atmosphere (TOA) and surface from the CERES SSF product for a month are sorted by 1-degree spatial regions and by the local hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the SFC along with other flux statistics and scene information. These average fluxes are given for both clear-sky and total-sky scenes. The regional cloud properties are column averaged and are included on the SFC. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2005-12-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=100] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

  4. CERES Monthly Gridded Single Satellite TOA and Surfaces/Clouds (SFC) data in HDF (CER_SFC_Terra-FM1-MODIS_Edition2B)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    The Monthly Gridded TOA/Surface Fluxes and Clouds (SFC) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SFC is also produced for combinations of scanner instruments. All instantaneous shortwave, longwave, and window fluxes at the Top-of-the-Atmosphere (TOA) and surface from the CERES SSF product for a month are sorted by 1-degree spatial regions and by the local hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the SFC along with other flux statistics and scene information. These average fluxes are given for both clear-sky and total-sky scenes. The regional cloud properties are column averaged and are included on the SFC. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2003-10-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=100] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

  5. CERES Monthly Gridded Single Satellite TOA and Surfaces/Clouds(SFC) data in HDF (CER_SFC_Aqua-FM3-MODIS_Edition1B)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    The Monthly Gridded TOA/Surface Fluxes and Clouds (SFC) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SFC is also produced for combinations of scanner instruments. All instantaneous shortwave, longwave, and window fluxes at the Top-of-the-Atmosphere (TOA) and surface from the CERES SSF product for a month are sorted by 1-degree spatial regions and by the local hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the SFC along with other flux statistics and scene information. These average fluxes are given for both clear-sky and total-sky scenes. The regional cloud properties are column averaged and are included on the SFC. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2005-03-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=100] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

  6. CERES Monthly Gridded Single Satellite TOA and Surfaces/Clouds (SFC) data in HDF (CER_SFC_Terra-FM1-MODIS_Edition2C)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    The Monthly Gridded TOA/Surface Fluxes and Clouds (SFC) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SFC is also produced for combinations of scanner instruments. All instantaneous shortwave, longwave, and window fluxes at the Top-of-the-Atmosphere (TOA) and surface from the CERES SSF product for a month are sorted by 1-degree spatial regions and by the local hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the SFC along with other flux statistics and scene information. These average fluxes are given for both clear-sky and total-sky scenes. The regional cloud properties are column averaged and are included on the SFC. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2005-12-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=100] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

  7. CERES Monthly Gridded Single Satellite TOA and Surfaces/Clouds (SFC) data in HDF (CER_SFC_Terra-FM2-MODIS_Edition2A)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    The Monthly Gridded TOA/Surface Fluxes and Clouds (SFC) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SFC is also produced for combinations of scanner instruments. All instantaneous shortwave, longwave, and window fluxes at the Top-of-the-Atmosphere (TOA) and surface from the CERES SSF product for a month are sorted by 1-degree spatial regions and by the local hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the SFC along with other flux statistics and scene information. These average fluxes are given for both clear-sky and total-sky scenes. The regional cloud properties are column averaged and are included on the SFC. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2003-12-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=100] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

  8. CERES Monthly Gridded Single Satellite TOA and Surfaces/Clouds (SFC) data in HDF (CER_SFC_Aqua-FM4-MODIS_Edition2A)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    The Monthly Gridded TOA/Surface Fluxes and Clouds (SFC) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SFC is also produced for combinations of scanner instruments. All instantaneous shortwave, longwave, and window fluxes at the Top-of-the-Atmosphere (TOA) and surface from the CERES SSF product for a month are sorted by 1-degree spatial regions and by the local hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the SFC along with other flux statistics and scene information. These average fluxes are given for both clear-sky and total-sky scenes. The regional cloud properties are column averaged and are included on the SFC. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2005-03-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=100] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

  9. CERES Monthly Gridded Single Satellite TOA and Surfaces/Clouds (SFC) data in HDF (CER_SFC_Aqua-FM3-MODIS_Edition2A)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    The Monthly Gridded TOA/Surface Fluxes and Clouds (SFC) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SFC is also produced for combinations of scanner instruments. All instantaneous shortwave, longwave, and window fluxes at the Top-of-the-Atmosphere (TOA) and surface from the CERES SSF product for a month are sorted by 1-degree spatial regions and by the local hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the SFC along with other flux statistics and scene information. These average fluxes are given for both clear-sky and total-sky scenes. The regional cloud properties are column averaged and are included on the SFC. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2005-12-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=100] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

  10. CERES Monthly Gridded Single Satellite TOA and Surfaces/Clouds(SFC) data in HDF (CER_SFC_Aqua-FM4-MODIS_Edition1B)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    The Monthly Gridded TOA/Surface Fluxes and Clouds (SFC) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SFC is also produced for combinations of scanner instruments. All instantaneous shortwave, longwave, and window fluxes at the Top-of-the-Atmosphere (TOA) and surface from the CERES SSF product for a month are sorted by 1-degree spatial regions and by the local hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the SFC along with other flux statistics and scene information. These average fluxes are given for both clear-sky and total-sky scenes. The regional cloud properties are column averaged and are included on the SFC. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2005-03-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=100] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

  11. CERES Monthly Gridded Single Satellite TOA and Surfaces/Clouds (SFC) data in HDF (CER_SFC_TRMM-PFM-VIRS_Beta4)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    The Monthly Gridded TOA/Surface Fluxes and Clouds (SFC) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SFC is also produced for combinations of scanner instruments. All instantaneous shortwave, longwave, and window fluxes at the Top-of-the-Atmosphere (TOA) and surface from the CERES SSF product for a month are sorted by 1-degree spatial regions and by the local hour of observation. The mean of the instantaneous fluxes for a given region-hour bin is determined and recorded on the SFC along with other flux statistics and scene information. These average fluxes are given for both clear-sky and total-sky scenes. The regional cloud properties are column averaged and are included on the SFC. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-01-01; Stop_Date=2000-03-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=100] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 hour; Temporal_Resolution_Range=Hourly - < Daily].

  12. MOPITT Gridded Monthly CO Retrievals V004

    Data.gov (United States)

    National Aeronautics and Space Administration — This product averages the daily L2 swath data into a 1x1 degree grid. Day and night passes are kept separate. Averaging kernels for each retrieval are provided...

  13. TES/Aura L3 CO Monthly Gridded V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  14. TES/Aura L3 CO Monthly Gridded V001

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  15. TES/Aura L3 HDO Monthly Gridded V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  16. TES/Aura L3 CO Monthly Gridded V002

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  17. TES/Aura L3 HDO Monthly Gridded V001

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  18. TES/Aura L3 HDO Monthly Gridded V002

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  19. Synchronization in single-phase grid-connected photovoltaic systems under grid faults

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede

    2012-01-01

    The highly increasing penetration of single-phase photovoltaic (PV) systems pushes the grid requirements related to the integration of PV power systems to be updated. These upcoming regulations are expected to direct the grid-connected renewable generators to support the grid operation...... and stability both under grid faulty conditions and under normal operations. Grid synchronization techniques play an important role in the control of single-phase systems in order to fulfill these demands. Thus, it is necessary to evaluate the behaviors of grid synchronization methods in single phase systems...... under grid faults. The focus of this paper is put on the benchmarking of synchronization techniques, mainly about phase locked loop (PLL) based methods, in single-phase PV power systems operating under grid faults. Some faulty mode cases are studied at the end of this paper in order to compare...

  20. Production of single-walled carbon nanotube grids

    Science.gov (United States)

    Hauge, Robert H; Xu, Ya-Qiong; Pheasant, Sean

    2013-12-03

    A method of forming a nanotube grid includes placing a plurality of catalyst nanoparticles on a grid framework, contacting the catalyst nanoparticles with a gas mixture that includes hydrogen and a carbon source in a reaction chamber, forming an activated gas from the gas mixture, heating the grid framework and activated gas, and controlling a growth time to generate a single-wall carbon nanotube array radially about the grid framework. A filter membrane may be produced by this method.

  1. MOPITT Gridded Monthly CO Retrievals (Thermal Infrared Radiances) V006

    Data.gov (United States)

    National Aeronautics and Space Administration — This product averages the daily L2 swath data into a 1x1 degree grid. Day and night passes are kept separate. Averaging kernels for each retrieval are provided...

  2. MOPITT Gridded Monthly CO Retrievals (Near Infrared Radiances) V006

    Data.gov (United States)

    National Aeronautics and Space Administration — This product averages the daily L2 swath data into a 1x1 degree grid. Day and night passes are kept separate. Averaging kernels for each retrieval are provided...

  3. MOPITT Gridded Monthly CO Retrievals (Thermal Infrared Radiances) V005

    Data.gov (United States)

    National Aeronautics and Space Administration — This product averages the daily L2 swath data into a 1x1 degree grid. Day and night passes are kept separate. Averaging kernels for each retrieval are provided...

  4. MOPITT Gridded Monthly CO Retrievals (Near Infrared Radiances) V005

    Data.gov (United States)

    National Aeronautics and Space Administration — This product averages the daily L2 swath data into a 1x1 degree grid. Day and night passes are kept separate. Averaging kernels for each retrieval are provided...

  5. Benchmarking of grid fault modes in single-phase grid-connected photovoltaic systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang

    2012-01-01

    Pushed by the booming installations of single-phase photovoltaic (PV) systems, the grid demands regarding the integration of PV systems are expected to be modified. Hence, the future PV systems should become more active with functionalities of low voltage ride-through (LVRT) and the grid support...... phase systems under grid faults. The intent of this paper is to present a benchmarking of grid fault modes that might come in future single-phase PV systems. In order to map future challenges, the relevant detection and control strategies are discussed. Some faulty modes are studied experimentally...... and provided at the end of this paper. It is concluded that there are extensive control possibilities in single-phase PV systems under grid faults. The Second Order General Integral based PLL technique might be the most promising candidate for future single-phase PV systems because of its fast adaptive...

  6. Coplanar interdigitated grid detector with single electrode readout

    Science.gov (United States)

    Luke, Paul N.

    2001-01-01

    The coplanar interdigitated grid technique with single electrode readout provides substantial spectral performance improvement over that of conventional full-area planar electrode detectors and over coplanar interdigitated grid detectors which measure the difference between the induced charge signals from two interdigitated coplanar grid electrodes. The signal from only one interdigitated grid electrode is read out. The signal response is optimized by changing the relative areas of the two grid electrodes and the bias applied across the detector. Only one preamplifier is needed and signal subtraction is not necessary. This eliminates the electronic noise contribution from the additional preamplifier used in the normal coplanar grid implementation, and conventional single-amplifier detector electronics can be used.

  7. Benchmarking of Grid Fault Modes in Single-Phase Grid-Connected Photovoltaic Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang

    2013-01-01

    Pushed by the booming installations of singlephase photovoltaic (PV) systems, the grid demands regarding the integration of PV systems are expected to be modified. Hence, the future PV systems should become more active with functionalities of Low Voltage Ride-Through (LVRT) and grid support...... phase systems under grid faults. The intent of this paper is to present a benchmarking of grid fault modes that might come in future single-phase PV systems. In order to map future challenges, the relevant synchronization and control strategies are discussed. Some faulty modes are studied experimentally...... and provided at the end of this paper. It is concluded that there are extensive control possibilities in single-phase PV systems under grid faults. The Second Order General Integral based PLL technique might be the most promising candidate for future single-phase PV systems because of its fast adaptive...

  8. Current Harmonics from Single-Phase Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2016-01-01

    is focused on the impacts of the power factor and the feed-in grid current level on the quality of the feed-in grid current from single-phase inverters. As a consequence, an internal model principle based high performance current control solution is tailor-made and developed for single-phase grid...... factor, or in the low voltage ride through mode with reactive current injection. In this paper, the mechanism of the harmonic current injection from grid-connected single-phase inverter systems is thus explored, and the analysis is conducted on single-phase PV systems. In particular, the analysis......-connected systems to produce high quality currents in different operation conditions, where a design procedure is also provided. The developed current controller in this paper can achieve a minimum steady-state error while maintaining a relatively fast transient response, and also being feasible in other single...

  9. TES/Aura L3 NH3 Monthly Gridded V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric vertical profiles estimates and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset...

  10. TES/Aura L3 CO2 Monthly Gridded V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric vertical profiles estimates and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset...

  11. TES/Aura L3 O3 Monthly Gridded V001

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  12. TES/Aura L3 CO2 Lite Monthly Gridded V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly avgs. of atmospheric vert. profile estimates and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and subsetted TES...

  13. TES/Aura L3 O3 Monthly Gridded V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  14. TES/Aura L3 CH4 Monthly Gridded V001

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  15. TES/Aura L3 O3 Monthly Gridded V002

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  16. TES/Aura L3 CH4 Monthly Gridded V002

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  17. TES/Aura L3 Atmospheric Temperatures Monthly Gridded V002

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  18. TES/Aura L3 Atmospheric Temperatures Monthly Gridded V001

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  19. TES/Aura L3 Atmospheric Temperatures Monthly Gridded V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  20. TES/Aura L3 H2O Monthly Gridded V002

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  1. TES/Aura L3 H2O Monthly Gridded V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  2. TES/Aura L3 CH4 Monthly Gridded V003

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  3. TES/Aura L3 H2O Monthly Gridded V001

    Data.gov (United States)

    National Aeronautics and Space Administration — Monthly averages of atmospheric temperature and VMR for atmospheric species are provided at 2 deg. lat. X 4 deg. long. spatial grids and at a subset of TES standard...

  4. Improved PLL structures for single-phase grid inverters

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Teodorescu, Remus; Blaabjerg, Frede

    2005-01-01

    of the reference signals. This paper presents two improved phase-locked-loop (PLL) methods for single-phase grid connected systems. The investigated PLL methods are based on a transport delay method and an inverse Park transformation method. The improvements in the case of using the delay-based PLL are: non...

  5. Dynamics Assessment of Grid-Synchronization Algorithms for Single-Phase Grid-Connected Converters

    DEFF Research Database (Denmark)

    Han, Yang; Luo, Mingyu; Guerrero, Josep M.

    2015-01-01

    Several advanced phase-lock-loop (PLL) algorithms have been proposed for single-phase power electronic systems. Among these algorithms, the orthogonal signal generators (OSGs) are widely utilized to generate a set of in-quadrature signals, owing to its benefit of simple digital implementation...... and low computational burden. Meanwhile, some other techniques have been proposed to enhance system robustness and stability characteristics. In this paper, a comprehensive comparison among the OSG-based PLLs and the advanced single-phase PLLs is presented when the grid voltage undergoes disturbances......, and the performance comparison of transient response and disturbance rejection capabilities are presented. Finally, the moving average filter (MAF) is applied to enhance steady state and dynamic response of the delayed-type PLL, derivator-based PLL and the complex-coefficient filter (CCF-PLL) under grid frequency...

  6. Improved PLL structures for single-phase grid inverters

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Teodorescu, Remus; Blaabjerg, Frede

    2005-01-01

    of the reference signals. This paper presents two improved phase-locked-loop (PLL) methods for single-phase grid connected systems. The investigated PLL methods are based on a transport delay method and an inverse Park transformation method. The improvements in the case of using the delay-based PLL are: non......-frequency dependent and better filtering of the harmonics. For the other investigated PLL method based on inverse Park transformation the improvement consists of better filtering of the harmonics. Experimental results validate the effectiveness of the two proposed methods....

  7. Synoptic Monthly Gridded WOD Absolute Geostrophic Velocity (SMG-WOD-V) (January 1945 - December 2014) with the P-Vector Method (NCEI Accession 0146195)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The SMG-WOD-V dataset comprises synoptic monthly global gridded fields of absolute geostrophic velocity inverted from the synoptic monthly gridded WOD temperature...

  8. Online grid impedance estimation for single-phase grid-connected systems using PQ variations

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Teodorescu, Remus; Rodriguez, Pedro;

    2007-01-01

    algorithms are used in order to estimate the value of the grid impedance. The online grid impedance estimation method can be used for compliance with the anti-islanding standard requirements (IEEE1574, IEEE929 and VDE0126) and for adaptive control of the grid-connected converters. The proposed method...

  9. Frequency Adaptive Repetitive Control of Grid-Tied Single-Phase PV Inverters

    DEFF Research Database (Denmark)

    Zhou, Keliang; Yang, Yongheng; Blaabjerg, Frede

    2015-01-01

    . This paper thus explores a frequency adaptive repetitive control strategy for grid converters, which employs fractional delay filters in order to adapt to the change of the grid frequency. Case studies with experimental results of a single-phase grid-connected PV inverter system are provided to verify...

  10. Challenges to Grid Synchronization of Single-Phase Grid-Connected Inverters in Zero-Voltage Ride-Through Operation

    DEFF Research Database (Denmark)

    Zhang, Zhen; Yang, Yongheng; Blaabjerg, Frede

    2016-01-01

    to remain connected under grid voltage sags (even zero voltage condition). In this case, much attention should be paid to the grid synchronization in such a way to properly ride-through grid faults. Thus, in this paper, the most commonly-used and recently-developed Phase Locked Loop (PLL) synchronization...... methods have been evaluated for single-phase grid-connected PV systems in the case of Zero-Voltage Ride-Through (ZVRT) operation. The performances of the prior-art PLL methods in response to zero voltage faults in terms of detection precision and dynamic response are assessed in this paper. Simulation...... results show that the Enhanced PLL (EPLL) and the Second Order Generalized Integrator based PLL (SOGI-PLL) are the most applicable to single-phase PV systems for ZVRT operation....

  11. A Synchronization Scheme for Single-Phase Grid-Tied Inverters under Harmonic Distortion and Grid Disturbances

    DEFF Research Database (Denmark)

    Hadjidemetriou, Lenos; Yang, Yongheng; Kyriakides, Elias;

    2017-01-01

    Synchronization is a crucial aspect in grid-tied systems, including single-phase photovoltaic inverters, and it can affect the overall performance of the system. Among prior-art synchronization schemes, the Multi Harmonic Decoupling Cell Phase-Locked Loop (MHDC-PLL) presents a fast response under...... are provided, which show that the proposed synchronization (i.e., the frequency adaptive MHDC-PLL) can achieve a fast and accurate response under any grid disturbance and/or severe harmonic conditions....

  12. Challenges to Grid Synchronization of Single-Phase Grid-Connected Inverters in Zero-Voltage Ride-Through Operation

    DEFF Research Database (Denmark)

    Zhang, Zhen; Yang, Yongheng; Blaabjerg, Frede;

    2016-01-01

    methods have been evaluated for single-phase grid-connected PV systems in the case of Zero-Voltage Ride-Through (ZVRT) operation. The performances of the prior-art PLL methods in response to zero voltage faults in terms of detection precision and dynamic response are assessed in this paper. Simulation......With the fast development in Photovoltaic (PV) technology, the relevant grid-connection requirements/standards are continuously being updated, and more challenges have been imposed on both single-phase and three-phase grid-connected PV systems. For instance, PV systems are currently required...... results show that the Enhanced PLL (EPLL) and the Second Order Generalized Integrator based PLL (SOGI-PLL) are the most applicable to single-phase PV systems for ZVRT operation....

  13. Droplet Measurement below Single-Layer Grid Fill

    Directory of Open Access Journals (Sweden)

    Vitkovic Pavol

    2016-01-01

    Full Text Available The main part of the heat transfer in a cooling tower is in a fill zone. This one is consist of a cooling fill. For the cooling tower is used a film fill or grid fill or splash fill in the generally. The grid fill has lower heat transfer performance like film fill usually. But their advantage is high resistance to blockage of the fill. The grid fill is consisted with independent layers made from plastic usually. The layers consist of several bars connected to the different shapes. For experiment was used the rhombus shape. The drops diameter was measured above and below the Grid fill.

  14. Synoptic monthly gridded three dimensional (3D) World Ocean Database temperature and salinity from January 1945 to December 2014 (NCEI Accession 0140938)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The synoptic gridded WOD (SG-WOD) provides 3D world ocean gridded temperature and salinity data in monthly increment from WOD profiles using the Optimal Spectral...

  15. Synoptic monthly gridded Global Temperature and Salinity Profile Programme (GTSPP) water temperature and salinity from January 1990 to December 2009 (NCEI Accession 0138647)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The synoptic gridded Global Temperature and Salinity Profile Programme (SG-GTSPP) provides world ocean 3D gridded temperature and salinity data in monthly increment...

  16. Stress Analysis of Single Spacer Grid Support considering Fuel Rod

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Y. G.; Jung, D. H.; Kim, J. H. [Chungnam National University, Daejeon (Korea, Republic of); Park, J. K.; Jeon, K. L. [Korea Nuclear Fuel, Daejeon (Korea, Republic of)

    2010-10-15

    Pressurized water reactor (PWR) nuclear fuel assembly is mainly composed of a top-end piece, a bottom-end piece, lots of fuel rods, and several spacer grids. Among them, the main function of spacer grid is protecting fuel rods from Fluid Induced Vibration (FIV). The cross section of spacer grid assembled by laser welding in upper and lower point. When the fuel rod inserted in spacer gird, spring and dimple and around of welded area got a stresses. The main hypothesis of this analysis is the boundary area of HAZ and base metal can get a lot of damage than other area by FIV. So, design factors of spacer grid mainly considered to preventing the fatigue failure in HAZ and spring and dimple of spacer grid. From previous researching, the environment in reactor verified. Pressure and temperature of light water observed 15MPa and 320 .deg. C, and vibration of the fuel rod observed within 0 {approx} 50Hz. In this study, mechanical properties of zirconium alloy that extracted from the test and the spacer grid model which used in the PWR were applied in stress analyzing. General-purpose finite element analysis program was used ANSYS Workbench 12.0.1 version. 3-D CAD program CATIA was used to create spacer grid model

  17. Central Control of Heat Pump for Smart Grid Purposes Tested on Single Family Houses

    DEFF Research Database (Denmark)

    Pedersen, Tom S.; Andersen, Palle; Nielsen, Kirsten M.

    2013-01-01

    A challenge in Denmark in the near future is to balance the electrical grid due to a large increase in the renewable energy production mainly from wind turbines. In this work a central control system using heat pumps in single family houses to help balancing the grid is investigated. The central...

  18. S4 Grid-Connected Single-Phase Transformerless Inverter for PV Application

    DEFF Research Database (Denmark)

    Ardashir, Jaber Fallah; Siwakoti, Yam Prasad; Sabahi, Mehran

    2016-01-01

    This paper introduces a new single-phase transformerless inverter for grid-connected photovoltaic systems with low leakage current. It consists of four power switches, two diodes, two capacitors and a filter at the output stage. The neutral of the grid is directly connected to the negative termin...

  19. Central Control of Heat Pump for Smart Grid Purposes Tested on Single Family Houses

    DEFF Research Database (Denmark)

    Pedersen, Tom S.; Andersen, Palle; Nielsen, Kirsten M.

    2013-01-01

    A challenge in Denmark in the near future is to balance the electrical grid due to a large increase in the renewable energy production mainly from wind turbines. In this work a central control system using heat pumps in single family houses to help balancing the grid is investigated. The central...

  20. MOPITT Gridded Monthly CO Retrievals (Near and Thermal Infrared Radiances) V005

    Data.gov (United States)

    National Aeronautics and Space Administration — This product averages the daily L2 swath data into a 1x1 degree grid. Day and night passes are kept separate. Averaging kernels for each retrieval are provided...

  1. MOPITT Gridded Monthly CO Retrievals (Near and Thermal Infrared Radiances) V006

    Data.gov (United States)

    National Aeronautics and Space Administration — This product averages the daily L2 swath data into a 1x1 degree grid. Day and night passes are kept separate. Averaging kernels for each retrieval are provided...

  2. Overview of Single-Phase Grid-Connected Photovoltaic Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede

    2015-01-01

    A still booming installation of solar photovoltaic (PV) systems has been witnessed worldwide. It is mainly driven by the demand of “clean” power generation. Grid-connected PV systems will become an even active player in the future mixed power systems, which are linked by a vast of power electronics...

  3. A Synchronization Scheme for Single-Phase Grid-Tied Inverters Under Harmonic Distortion and Grid Disturbances

    DEFF Research Database (Denmark)

    Hadjidemetriou, Lenos; Kyriakides, Elias; Yang, Yongheng

    2016-01-01

    Synchronization is a crucial aspect in grid-tied systems, including single-phase photovoltaic inverters, and it can affect the overall performance of the system. Among prior-art synchronization schemes, the Multi Harmonic Decoupling Cell Phase-Locked Loop (MHDC-PLL) presents a fast response under...... grid disturbances and high accuracy under harmonic distortions. However, major drawbacks of the MHDC-PLL include increased complexity and inaccurate response under non-nominal frequencies, which may occur in practical applications. Thus, this paper proposes strategies to address these issues. At first......, a novel re-formulation of an equivalent decoupling cell is proposed for reducing the implementation complexity, and then a frequency adaptive quadrature signal generator for the MHDC-PLL is proposed to enable an accurate response even under non-nominal frequencies. Simulation and experimental results...

  4. Single stage grid converters for battery energy storage

    DEFF Research Database (Denmark)

    Trintis, Ionut; Munk-Nielsen, Stig; Teodorescu, Remus

    2010-01-01

    Integration of renewable energy systems in the power system network such as wind and solar is still a challenge in our days. Energy storage systems (ESS) can overcome the disadvantage of volatile generation of the renewable energy sources. This paper presents power converters for battery energy...... storage systems (BESS) which can interface mediumvoltage batteries to the grid. Converter topologies comparison is performed in terms of efficiency, common mode voltage and redundancy for a 6kV series connected medium voltage batteries with a nominal power of 5MVA to act as a battery charger/discharger....

  5. Empirical laws of particle extraction from single-grid source of bipolar ion-electron flow

    Energy Technology Data Exchange (ETDEWEB)

    Dudin, S. V. [Department of Physics and Technology, V.N. Karazin Kharkiv National University, Kurchatova Ave. 31, 61108 Kharkiv (Ukraine); Scientific Center of Physical Technologies, Svobody sq. 6, 61022 Kharkiv (Ukraine); Rafalskyi, D. V. [Scientific Center of Physical Technologies, Svobody sq. 6, 61022 Kharkiv (Ukraine)

    2012-11-15

    The present research is devoted to the problem of extraction grid choice for a single-grid source of bipolar ion-electron flow. The paper contains detailed reference information on ion and electron extraction characteristics of 10 different grids with broad range of parameters: aperture width (0.09-0.6 mm), grid transparency (0.19-0.51), thickness (0.036-0.5 mm), and with different aperture geometry. The grids with square, circular, and slit apertures were made with different technologies: laser cutting, welding, weaving, and electrolytic erosion. The general regularities of the ion and electron extraction from the single-grid source are experimentally researched for the cases of dc and RF extraction grid biasing. A conclusion has been made that the maximum extracted ion current at low ion energy (0-200 eV) does not significantly vary for all the grids and does not exceed half of the primary ion current from plasma multiplied by the optical grid transparency. The low-energy limit of efficient ion extraction has been discovered which cannot be overcome by the aperture narrowing. A conclusion is made that the RF extraction mode is superior for all the researched grids since it is characterized by higher extracted ion current at any acceleration voltage for any grid with much more simple and smooth extraction curves behavior in comparison to the dc case as well as absence of arcing, jumps, and hysteresis of the measured curves at any RF voltages. The unique ability of the RF biased single-grid source of simultaneous ion/electron emission has been studied. The measured maximal attainable ion beam current compensation ratio is always sufficiently higher than 1 and typically varies in the range 2-6. The results obtained in the present paper demonstrate prospective of the single-grid source in space thruster applications and in modern technologies, particularly for ion beam processing of wide bandgap semiconductor devices such as GaN and SiC transistors due to inherent

  6. Single-Board-Computer-Based Traffic Generator for a Heterogeneous and Hybrid Smart Grid Communication Network

    Directory of Open Access Journals (Sweden)

    Do Nguyet Quang

    2014-02-01

    Full Text Available In smart grid communication implementation, network traffic pattern is one of the main factors that affect the system’s performance. Examining different traffic patterns in smart grid is therefore crucial when analyzing the network performance. Due to the heterogeneous and hybrid nature of smart grid, the type of traffic distribution in the network is still unknown. The traffic that popularly used for simulation and analysis no longer reflects the real traffic in a multi-technology and bi-directional communication system. Hence, in this study, a single-board computer is implemented as a traffic generator which can generate network traffic similar to those generated by various applications in the fully operational smart grid. By placing in a strategic and appropriate position, a collection of traffic generators allow network administrators to investigate and test the effect of heavy traffic on performance of smart grid communication system.

  7. A Control Strategy for Single-phase Grid-Connected Inverter with Power Quality Regulatory Function

    Directory of Open Access Journals (Sweden)

    Luo Ling

    2013-07-01

    Full Text Available A single-phase grid-connected inverter system based on LCL filter is established,which combines the features of inverter and active power filter. A composite control strategy for grid-connected inverter with the function of implementing reactive power compensation and harmonic compensation in the grid-connected power generation is proposed. Firstly, grid-connected inverter system structure and model is analyzed. A quasi-Proportional Resonant control method to gain the control of grid-connected fundamental wave current containing reactive power compensation current as well as the control of harmonic compensation currents is put forward; then the calculation methods of  composite control command current based on both second order generalized integrator-quadrature signal generator (SOGI-QSG and instantaneous reactive power theory are given. Finally, the effectiveness of the control strategy proposed in this paper is verified by simulation.

  8. A Synchronization Method for Single-Phase Grid-Tied Inverters

    DEFF Research Database (Denmark)

    Hadjidemetriou, Lenos; Kyriakides, Elias; Yang, Yongheng;

    2016-01-01

    The controllers of single-phase grid-tied inverters require improvements to enable distribution generation systems to meet the grid codes/standards with respect to power quality and the fault ride through capability. In that case, the response of the selected synchronization technique is crucial...... for the performance of the entire grid-tied inverter. In this paper, a new synchronization method with good dynamics and high accuracy under a highly distorted voltage is proposed. This method uses a Multi-Harmonic Decoupling Cell (MHDC), which thus can cancel out the oscillations on the synchronization signals due...

  9. Maximum Power Point Tracking and Reactive Power Control of Single Stage Grid Connected Photovoltaic System

    OpenAIRE

    2011-01-01

    Single-stage grid-connected Photovoltaic (PV) systems have advantages such as simple topology, high efficiency, etc. However, since all the control objectives such as the maximum power point tracking (with the utility voltage, and harmonics reduction for output current need to be considered simultaneously, the complexity of the control scheme is much increased. In this paper a new type of grid connected photovoltaic (PV) system with Maximum Power Point Tracking (MPPT) and reactive power simul...

  10. A review of single-phase grid-connected inverters for photovoltaic modules

    DEFF Research Database (Denmark)

    Kjaer, Soren Baekhoej; Pedersen, John Kim; Blaabjerg, Frede

    2005-01-01

    This review focuses on inverter technologies for connecting photovoltaic (PV) modules to a single-phase grid. The inverters are categorized into four classifications: 1) the number of power processing stages in cascade; 2) the type of power decoupling between the PV module(s) and the single...

  11. Lyapunov-Based Control Scheme for Single-Phase Grid-Connected PV Central Inverters

    NARCIS (Netherlands)

    Meza, C.; Biel, D.; Jeltsema, D.; Scherpen, J. M. A.

    2012-01-01

    A Lyapunov-based control scheme for single-phase single-stage grid-connected photovoltaic central inverters is presented. Besides rendering the closed-loop system globally stable, the designed controller is able to deal with the system uncertainty that depends on the solar irradiance. A laboratory p

  12. Lyapunov-Based Control Scheme for Single-Phase Grid-Connected PV Central Inverters

    NARCIS (Netherlands)

    Meza, C.; Biel, D.; Jeltsema, D.; Scherpen, J. M. A.

    2012-01-01

    A Lyapunov-based control scheme for single-phase single-stage grid-connected photovoltaic central inverters is presented. Besides rendering the closed-loop system globally stable, the designed controller is able to deal with the system uncertainty that depends on the solar irradiance. A laboratory p

  13. Grid to vehicle and vehicle to grid energy transfer using single ...

    African Journals Online (AJOL)

    user

    where Vsm is the maximum value of the source voltage the value of Vsm is 325V for Vs = 230V rms and ω = 2πf. .... where P is conversion power, Vdc (Vo1+Vo2) is input voltage and Vb is output voltage and fsw is ..... A review of single-phase.

  14. Harmonics Suppression for Single-Phase Grid-Connected Photovoltaic Systems in Different Operation Modes

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2013-01-01

    As the penetration of grid-connected photovoltaic (PV) systems is booming, specific grid demands are imposed on such interconnected PV systems. Therefore, achieving high reliable PV systems with high power quality is of intense interest. However, the injected current from single-phase grid-connected......-phase grid-connected PV systems in different operation modes. Especially, it can remove higher order harmonics effectively leading to a better power quality compared to the Proportional plus Multi-Resonant Controller, and it has less computational burden....... PV inverters may be severely affected in different operation modes. In this paper, a detailed analysis is conducted to reveal the relationship between the harmonics level with the power factor and the current level in the PV systems. A current control solution which employs an Internal Model...

  15. TOMS/Nimbus-7 UV Reflectivity Monthly L3 Global 1x1.25 deg Lat/Lon Grid V008

    Data.gov (United States)

    National Aeronautics and Space Administration — This data product contains TOMS/Nimbus-7 UV Reflectivity Monthly L3 Global 1x1.25 deg Lat/Lon Grid Version 8 data in ASCII format. The Total Ozone Mapping...

  16. Synoptic monthly gridded (0.25 degree) Gulf of Mexico (T, S, u, v) dataset (January 1945 ‐ December 2014) from the NOAA/NCEI WOD Profile Data (NCEI Accession 0156423)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The synoptic monthly gridded Gulf of Mexico dataset (SMG-GM) provides 3D gridded (T, S) and absolute geostrophic velocity (u,v) fields in monthly increment from WOD...

  17. Experimental Study on a Single Layer Two-Way Grid Shell with Tension Members

    Institute of Scientific and Technical Information of China (English)

    Zhonghao Zhang; Masumi Fujimoto; Atsuo Takino; Katsuhiko Imai

    2015-01-01

    Single layer two⁃way grid shell with in⁃plane and out⁃of⁃plane tension members is a new type of single⁃layer latticed shell roofs. Compared with traditional single⁃layer latticed shells, this new type has a unique mesh form and excellent rigidity. In order to further understand the buckling behaviors of single layer two⁃way grid cylindrical shell roof with tension members, the buckling experiments have been undertaken to investigate the effect of tension members, in either out⁃of⁃plane or in⁃plane placement. A single layer two⁃way grid cylindrical shell roof with out⁃of⁃plane tension members has been tested under symmetric and asymmetric loading. The tension member placement, the introducing initial axial force to tension members and the load patterns are considered to investigate the buckling behavior. Experimental results indicate that four long out⁃of⁃plane tension members work well under symmetrical loading, but only two long out⁃of⁃plane tension members work under asymmetrical loading. It can be concluded that the PC bar members used as tension members for this study are useful in the construction of a single layer two⁃way grid cylindrical shell roof with structural members intersecting at small angles.

  18. Single-Phase 3L PR Controlled qZS Inverter Connected to the Distorted Grid

    DEFF Research Database (Denmark)

    Makovenko, Elena; Husev, Oleksandr; Roncero-Clemente, Carlos

    2016-01-01

    This paper presents a single-phase three-level NPC qZS inverter connected to a distorted grid using PID and PR regulators. A case study system along with the control strategy are described. Tuning approaches for PID and PR regulators are addressed and validated by means of simulation results...

  19. S4 Grid-Connected Single-Phase Transformerless Inverter for PV Application

    DEFF Research Database (Denmark)

    Ardashir, Jaber Fallah; Siwakoti, Yam Prasad; Sabahi, Mehran;

    2016-01-01

    This paper introduces a new single-phase transformerless inverter for grid-connected photovoltaic systems with low leakage current. It consists of four power switches, two diodes, two capacitors and a filter at the output stage. The neutral of the grid is directly connected to the negative termin...... clearly verify the performance of the proposed inverter and its practical application for grid-connected PV systems.......This paper introduces a new single-phase transformerless inverter for grid-connected photovoltaic systems with low leakage current. It consists of four power switches, two diodes, two capacitors and a filter at the output stage. The neutral of the grid is directly connected to the negative terminal...... of the PV source. This results in a constant common-mode voltage and almost zero leakage current. A unipolar Sinusoidal Pulse-Width Modulation (SPWM) technique is used to modulate the inverter to reduce the output current ripple and the filter requirements. The main advantages of this inverter are compact...

  20. A Novel Flying Capacitor Transformerless Inverter for Single-Phase Grid Connected Solar Photovoltaic System

    DEFF Research Database (Denmark)

    Siwakoti, Yam Prasad; Blaabjerg, Frede

    2016-01-01

    This paper proposes a new single-phase flying capacitor transformerless PV inverter for grid-connected photovoltaic (PV) systems. The neutral of the grid can be directly connected to the negative terminal of the source (PV). It consists of four power switches, one diode, one capacitor and a small...... and some topologies, which requires two times of the peak ac-voltage magnitude) and, (5) the flying capacitor charges every switching cycle, which reduces the size of the required capacitor with switching frequency. In addition, industry standard half bridge module can be used in the new inverter without...

  1. An LLCL Power Filter for Single-Phase Grid-Tied Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; He, Yuanbin; Blaabjerg, Frede

    2012-01-01

    . Particularly, it can attenuate the switching-frequency current ripple components much better than an LCL filter, leading to a decrease in the total inductance and volume. Furthermore, by decreasing the inductance of a grid-side inductor, it raises the characteristic resonance frequency, which is beneficial...... to the inverter system control. The parameter design criteria of the proposed LLCL filter is also introduced. The comparative analysis and discussions regarding the traditional LCL filter and the proposed LLCL filter have been presented and evaluated through experiment on a 1.8-kW-single-phase grid-tied inverter...

  2. An Investigation of Energy Storage Possibilities in Single Family Houses for Smart Grid Purposes

    DEFF Research Database (Denmark)

    Andersen, Palle; Pedersen, Tom S.; Nielsen, Kirsten M.

    2014-01-01

    In Denmark it will be a challenge in near future to balance the electrical grid due to a large increase in the renewable energy production mainly from wind turbines. Smart grid solutions which exploit all storage capacities are essential to meet this challenge. In this work single family houses...... a year prediction models are analysed. The main topic of this work is to investigate how behaviour of inhabitants affect the quality of predictions. Unfortunately the output of the models for single inhabited single family houses seems to give large standard deviations of the predictions, and aggregated...... models for use in a coordinated control scheme could improve the possibility to use thermal capacity in houses as dynamical storages....

  3. Impact of dose size in single fraction spatially fractionated (grid) radiotherapy for melanoma

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hualin, E-mail: hualin.zhang@northwestern.edu, E-mail: hualinzhang@yahoo.com [Department of Radiation Oncology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611 and Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana 46202 (United States); Zhong, Hualiang [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan 48202 (United States); Barth, Rolf F. [Department of Pathology, The Ohio State University, Columbus, Ohio 43210 (United States); Cao, Minsong; Das, Indra J. [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, Indiana 46202 (United States)

    2014-02-15

    Purpose: To evaluate the impact of dose size in single fraction, spatially fractionated (grid) radiotherapy for selectively killing infiltrated melanoma cancer cells of different tumor sizes, using different radiobiological models. Methods: A Monte Carlo technique was employed to calculate the 3D dose distribution of a commercially available megavoltage grid collimator in a 6 MV beam. The linear-quadratic (LQ) and modified linear quadratic (MLQ) models were used separately to evaluate the therapeutic outcome of a series of single fraction regimens that employed grid therapy to treat both acute and late responding melanomas of varying sizes. The dose prescription point was at the center of the tumor volume. Dose sizes ranging from 1 to 30 Gy at 100% dose line were modeled. Tumors were either touching the skin surface or having their centers at a depth of 3 cm. The equivalent uniform dose (EUD) to the melanoma cells and the therapeutic ratio (TR) were defined by comparing grid therapy with the traditional open debulking field. The clinical outcomes from recent reports were used to verify the authors’ model. Results: Dose profiles at different depths and 3D dose distributions in a series of 3D melanomas treated with grid therapy were obtained. The EUDs and TRs for all sizes of 3D tumors involved at different doses were derived through the LQ and MLQ models, and a practical equation was derived. The EUD was only one fifth of the prescribed dose. The TR was dependent on the prescribed dose and on the LQ parameters of both the interspersed cancer and normal tissue cells. The results from the LQ model were consistent with those of the MLQ model. At 20 Gy, the EUD and TR by the LQ model were 2.8% higher and 1% lower than by the MLQ, while at 10 Gy, the EUD and TR as defined by the LQ model were only 1.4% higher and 0.8% lower, respectively. The dose volume histograms of grid therapy for a 10 cm tumor showed different dosimetric characteristics from those of conventional

  4. Analysis, Control and Experimental Verification of a Single-Phase Capacitive-Coupling Grid-Connected Inverter

    DEFF Research Database (Denmark)

    Dai, Ning-Yi; Zhang, Wen-Chen; Wong, Man-Chung;

    2015-01-01

    This study proposes a capacitive-coupling grid-connected inverter (CGCI), which consists of a full-bridge single-phase inverter coupled to a power grid via one capacitor in series with an inductor. The fundamental-frequency impedance of the coupling branch is capacitive. In contrast with the conv......This study proposes a capacitive-coupling grid-connected inverter (CGCI), which consists of a full-bridge single-phase inverter coupled to a power grid via one capacitor in series with an inductor. The fundamental-frequency impedance of the coupling branch is capacitive. In contrast...... with the conventional inductive-coupling grid-connected inverter (IGCI), this structure provides an alternative interface for use between a low-voltage DC microgrid and an AC grid. A comparison between the CGCI and the IGCI is performed. It is concluded that the CGCI is able to transfer active power and provide lagging...

  5. Grid Integration of Single Stage Solar PV System using Three-level Voltage Source Converter

    Science.gov (United States)

    Hussain, Ikhlaq; Kandpal, Maulik; Singh, Bhim

    2016-08-01

    This paper presents a single stage solar PV (photovoltaic) grid integrated power generating system using a three level voltage source converter (VSC) operating at low switching frequency of 900 Hz with robust synchronizing phase locked loop (RS-PLL) based control algorithm. To track the maximum power from solar PV array, an incremental conductance algorithm is used and this maximum power is fed to the grid via three-level VSC. The use of single stage system with three level VSC offers the advantage of low switching losses and the operation at high voltages and high power which results in enhancement of power quality in the proposed system. Simulated results validate the design and control algorithm under steady state and dynamic conditions.

  6. High Efficiency Single-stage Grid-tied PV Inverter for Renewable Energy System

    OpenAIRE

    2012-01-01

    A single-phase grid connected transformerless photovoltaic (PV) inverter for residential application is presented. The inverter is derived from a boost cascaded with buck converter along with a line frequency unfolding circuit. Due to its novel operating modes, high efficiency can be achieved because there is only one switch operating at high frequency at a time, and the converter allows the use of power MOSFET and ultra-fast reverse recovery diode. This dissertation begins with theoretical a...

  7. A Current-Forced Line-Commutated Inverter for Single-Phase Grid-Connected Photovoltaic Generation Systems

    OpenAIRE

    2015-01-01

    A simple power electronic interface based on the line-commutated inverter (LCI) has been developed in order to inject sinusoidal current to the grid for single-phase grid-connected photovoltaic (PV) energy generation systems. The proposed inverter facilitates controlling the injecting/grid current with a controllable power factor in contrast to the conventional LCI system. It is achieved that the total harmonic distortion (THD) of the injecting currents for the different firin...

  8. Zero-voltage ride-through capability of single-phase grid-connected photovoltaic systems

    DEFF Research Database (Denmark)

    Zhang, Zhen; Yang, Yongheng; Ma, Ruiqing

    2017-01-01

    that combining a fast and accurate synchronization mechanism with appropriate control strategies for the zero-voltage ride-through (ZVRT) operation is mandatory. Accordingly, the representative synchronization techniques (i.e., the phase-locked loop (PLL) methods) in the ZVRT operation are compared in terms...... of detection precision and dynamic response. It shows that the second-order generalized integrator (SOGI-PLL) is a promising solution for single-phase systems in the case of fault ride-through. A control strategy by modifying the SOGI-PLL scheme is then introduced to single-phase grid-connected PV systems...

  9. Improved Power Decoupling Scheme for Single-Phase Grid-Connected Differential Inverter with Realistic Mismatch in Storage Capacitances

    DEFF Research Database (Denmark)

    Yao, Wenli; Wang, Xiongfei; Loh, Poh Chiang;

    2017-01-01

    A single-phase differential inverter consists of two elementary dc-dc converters, sharing a common dc source and a common ac output terminal. The other ac terminals of the two converters are connected to the grid in the case of grid-connected applications. The differential inverter has subsequent...... provided have verified the computation and control scheme developed....

  10. Grid Sensitivity Analysis of Simulations of a Flow around a Single Rotating Wind Turbine Blade

    Science.gov (United States)

    Kaiser, Bryan E.; Snider, Michael A.; Poroseva, Svetlana V.; Hovsapian, Rob O.

    2012-11-01

    Design of a wind farm layout with the purpose of optimizing the power outcome requires accurate and reliable simulations of a flow around and behind wind turbines. Such computations are expensive even for a single turbine. To find an optimal set of simulation parameters that satisfies both requirements in simulation accuracy and cost in an acceptable degree, a sensitivity study on how the parameters' variation influences results of simulations should be conducted at the early stage of computations. In the current study, the impact of a grid refinement, grid stretching, and cell shape on simulation results is analyzed in a flow around a single rotating blade utilized in a mid-sized Rim Driven Wind Turbine design (U.S. Patent #7399162) developed by Keuka Energy LLC, and in its near wake. Simulation results obtained with structured and unstructured grids are compared. Industry relies on commercial software for conducting fluid flow simulations. Therefore, STAR-CCM+ software was used in our study. A choice of a turbulence model was made based on our previous sensitivity study of flow simulations over a rotating disk (see M. A. Snider, S. V. Poroseva, AIAA-2012-3146). Center for Advanced Power Systems, Florida State University.

  11. Low Voltage Ride-Through Capability of a Single-Stage Single-Phase Photovoltaic System Connected to the Low-Voltage Grid

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede

    2013-01-01

    The progressively growing of single-phase photovoltaic (PV) systems makes the Distribution System Operators (DSO) to update or revise the existing grid codes in order to guarantee the availability, quality and reliability of the electrical system. It is expected that the future PV systems connected...... to the low-voltage grid will be more active with functionalities of low voltage ride-through (LVRT) and the grid support capability, which is not the case today. In this paper, the operation principle is demonstrated for a single-phase grid-connected PV system in low voltage ride through operation in order...... to map future challenges. The system is verified by simulations and experiments. Test results show that the proposed power control method is effective and the single-phase PV inverters connected to low-voltage networks are ready to provide grid support and ride-through voltage fault capability...

  12. Design of a Neural Controller for Single Phase Inverter in Grid Connected Photovoltaic System

    Directory of Open Access Journals (Sweden)

    A. Ndiaye

    2014-02-01

    Full Text Available This study shows a neural network based control strategy of the current injected into a single-phase grid via an inverter. The inverter is supplied by a Photovoltaic Generator (PVG. The optimal control of PVG is ensured by an MPPT algorithm of type P and O (Perturbation-Observation. The synchronization of the inverter with the electrical grid is ensured by a Phase-Locked Loop (PLL device. The sizing and the modeling of the system components have been presented. A Neural Network Controller (NNC and a Proportional Integral (PI controller have been implemented and compared. Obtained results show that the NNC have faster response and lower THD without overshoots.

  13. Reactive Power Injection Strategies for Single-Phase Photovoltaic Systems Considering Grid Requirements

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

    2014-01-01

    like what the conventional power plants do today in the grid regulation participation. Requirements of ancillary services like Low-Voltage Ride-Through (LVRT) associated with reactive current injection and voltage support through reactive power control, have been in effectiveness in some countries...... possibilities are: a) constant average active power control, b) constant active current control, c) constant peak current control and d) thermal optimized control strategy. All those strategies comply with the currently active grid codes, but are with different objectives. The thermal optimized control strategy....... Those advanced features can be provided by next-generation PV systems, and will be enhanced in the future to ensure an even efficient and reliable utilization of PV systems. In the light of this, Reactive Power Injection (RPI) strategies for single-phase PV systems are explored in this paper. The RPI...

  14. Reactive Power Injection Strategies for Single-Phase Photovoltaic Systems Considering Grid Requirements

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

    2014-01-01

    like what the conventional power plants do today in the grid regulation participation. Requirements of ancillary services like Low-Voltage Ride-Through (LVRT) associated with reactive current injection and voltage support through reactive power control, have been in effectiveness in some countries, e...... in this paper. The RPI possibilities are: a) constant average active power control, b) constant active current control, c) constant peak current control and d) thermal optimized control strategy. All those strategies comply with the currently active grid codes, but are with different objectives. The proposed.......g. Germany and Italy. Those advanced features can be provided by next generation PV systems, and will be enhanced in the future to ensure an even efficient and reliable utilization of PV systems. In light of this, Reactive Power Injection (RPI) strategies for single-phase PV systems are explored...

  15. CONSERVATION OF THREE-POINT COMPACT SCHEMES ON SINGLE AND MULTIBLOCK PATCHED GRIDS FOR HYPERBOLIC PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    Zi-niu Wu

    2003-01-01

    For nonlinear hyperbolic problems, conservation of the numerical scheme is importantfor convergence to the correct weak solutions. In this paper the conservation of the well-known compact scheme up to fourth order of accuracy on a single and uniform grid isstudied, and a conservative interface treatment is derived for compact schemes on patchedgrids. For a pure initial value problem, the compact scheme is shown to be equivalent toa scheme in the usual conservative form. For the case of a mixed initial boundary valueproblem, the compact scheme is conservative only if the rounding errors are small enough.For a patched grid interface, a conservative interface condition useful for mesh refinementand for parallel computation is derived and its order of local accuracy is analyzed.

  16. Multi Port Single Stage Power Electronics Converter and Wind PFC Converter for DC Micro Grid Applications

    Directory of Open Access Journals (Sweden)

    M. Hemachandran

    2014-08-01

    Full Text Available In this study multi port AC/DC-DC single stage power electronics converter proposed for grid power supply. The topology includes reduced number of active element and passive element. Passive element is used to provide to achieve improved voltage gain and to reduce the voltage stress of input side switches. The active-clamp circuits are used to recycle the energy stored in the leakage inductors and to improve the system performances. Here two input port (wind and battery unit and output port connected to dc grid, battery act as charge unit and source. Efficient wind power conversion is achieved by PFC boost dc-dc converter. Controlled and high step up voltage is supplied to multi-port converter from wind source.

  17. Single-Phase Single-Stage PV-Grid System Using VSI Based on Simple Control Circuit

    Directory of Open Access Journals (Sweden)

    Slamet Riyadi

    2012-12-01

    Full Text Available Integrating electric energy generated by PV with utilities has been developed. Some of these using two-stage converters and the others using single stage converters. For systems with two-stage converters, the first stage converter acts as a MPPT to maximize power generated by PV and the second stage is used as an interface to the utilities. In the single-stage system, an inverter is used for both function. In this paper, PV-Grid System using a single-stage Voltage Source Inverter is proposed. The simple control circuit to make PV generate maximum power and keeping power equilibrium between PV and inverter output power is used. To verify the analysis, simulations are done.

  18. TOMS/Earth Probe UV Reflectivity Monthly L3 Global 1x1.25 deg Lat/Lon Grid V008

    Data.gov (United States)

    National Aeronautics and Space Administration — This data product contains TOMS/Earth Probe UV Reflectivity Monthly L3 Global 1x1.25 deg Lat/Lon Grid Version 8 data in ASCII format. (The shortname for this Level-3...

  19. Inter-annual variability of the acoustic propagation in the Yellow Sea identified from a Synoptic Monthly Gridded Database as compared with GDEM

    OpenAIRE

    2016-01-01

    Approved for public release; distribution is unlimited This research investigates the inter-annual acoustic variability in the Yellow Sea identified from the Synoptic Monthly Gridded-World Ocean Database (SMG-WOD) as compared with the Navy's Global Digital Environmental Model (GDEM). The SMG-WOD has a horizontal resolution of 1˚, 28 vertical levels from the surface to 3000 m depth and one-month temporal increments allowing individual years of acoustic data to be analyzed, whereas GDEM is a...

  20. The Influence of phase-locked loop on the stability of single-phase grid-connected inverter

    DEFF Research Database (Denmark)

    Zhang, Chong; Wang, Xiongfei; Blaabjerg, Frede;

    2015-01-01

    for avoiding the PLL induced instability in single-phase inverters. At last the relationship between PLL bandwidth and the Short Circuit Ratio (SCR) of the grid has been derived to guide the design of the PLL. Experimental results are presented in order to verify this analysis, and the resonant frequencies can...... admittance of single-phase current-controlled inverters with different grid stiffness is analyzed in this paper. It shows that the PLL introduces a negative paralleled admittance into the output admittance of the inverter, which may lead to unintentional low-order harmonic oscillation in a weak grid...

  1. Maximum Power Point Tracking and Reactive Power Control of Single Stage Grid Connected Photovoltaic System

    Directory of Open Access Journals (Sweden)

    Y. Hoseynpoor

    2011-12-01

    Full Text Available Single-stage grid-connected Photovoltaic (PV systems have advantages such as simple topology, high efficiency, etc. However, since all the control objectives such as the maximum power point tracking (with the utility voltage, and harmonics reduction for output current need to be considered simultaneously, the complexity of the control scheme is much increased. In this paper a new type of grid connected photovoltaic (PV system with Maximum Power Point Tracking (MPPT and reactive power simultaneous control system is presented. System has two controlling loops to obtain the maximum power from the PV array and also has reactive power control (RPC. In order to decrease the complexity, cost and the number of converters, a singlestage PV system is applied. Using RPC and MPPT controllers, reference current is calculated and the current with low THD (<5% is injected to grid through Adaptive Predictive Current Control (APCC and current Controlled Voltage Source Inverter (CCVSI. The operation of the system is classified in to two day and night modes. In day mode MPPT and RPC control is accomplished and in night mode RPC control is accomplished like STATCOM operation. Reactive power control is continuously performed correctly with appropriate speed in two inductive and capacitive modes in both day and night modes. Thus, System Utilization Factor (SUF increases to 100% which is just 20% for common PV systems. Mathematical modeling of the system and the results of simulations in MATLAB/SIMULINK software are presented to investigate the correctness of the results.

  2. Improved grid-noise removal in single-frame digital moiré 3D shape measurement

    Science.gov (United States)

    Mohammadi, Fatemeh; Kofman, Jonathan

    2016-11-01

    A single-frame grid-noise removal technique was developed for application in single-frame digital-moiré 3D shape measurement. The ability of the stationary wavelet transform (SWT) to prevent oscillation artifacts near discontinuities, and the ability of the Fourier transform (FFT) applied to wavelet coefficients to separate grid-noise from useful image information, were combined in a new technique, SWT-FFT, to remove grid-noise from moiré-pattern images generated by digital moiré. In comparison to previous grid-noise removal techniques in moiré, SWT-FFT avoids the requirement for mechanical translation of optical components and capture of multiple frames, to enable single-frame moiré-based measurement. Experiments using FFT, Discrete Wavelet Transform (DWT), DWT-FFT, and SWT-FFT were performed on moiré-pattern images containing grid noise, generated by digital moiré, for several test objects. SWT-FFT had the best performance in removing high-frequency grid-noise, both straight and curved lines, minimizing artifacts, and preserving the moiré pattern without blurring and degradation. SWT-FFT also had the lowest noise amplitude in the reconstructed height and lowest roughness index for all test objects, indicating best grid-noise removal in comparison to the other techniques.

  3. Analysis of phase-locked loop influence on the stability of single-phase grid-connected inverter

    DEFF Research Database (Denmark)

    Zhang, Chong; Wang, Xiongfei; Blaabjerg, Frede

    2015-01-01

    A controlled power inverter can cause instability at the point of common coupling (PCC) with its output filter and the grid. This paper analyzes the influence of the Phase-Locked Loop (PLL) on the output admittance of single-phase current-controlled inverters with different grid stiffness. It shows...... that the PLL introduces a paralleled admittance into the output admittance of the inverter, which may lead to unintentional low-order harmonic oscillation in a weak grid. Moreover, the Second Order Generalized Integrator PLL (SOGI-PLL) is also modeled. It is found that the quadrature signal generator of SOGI...... plays a stabilizing role in grid-inverter interactions, which thus provides a promising candidate for avoiding the PLL-induced instability in single-phase inverters. Simulation results are presented for verifying the theoretical analysis. The possible instability due to different PLL bandwidth is also...

  4. Single Phase PV Grid-Connected in Smart Household Energy System with Anticipation on Fault Conditions

    Directory of Open Access Journals (Sweden)

    Feri Yusivar

    2014-02-01

    Full Text Available This paper proposes an algorithm of Smart household energy systems to anticipate fault conditions in power system grid. Single phase PV grid-connected in smart household energy system is a smart system that determines electrical supply conditions to the load in residential electrical system. The smart system is consisted of two voltage source, conventional electricity system from national electricity provider as preferred source and photovoltaic as the alternative source. In smart system, fault conditions can be anticipated by selecting the appropriate voltage sources to supply the load. The condition of smart system can be described in power flow regulation to the load by detection and identification of amplitude, phase angle, and frequency of the voltage source compared to the system reference. The system mechanism is based on detection of voltage source using static transfer switch (STS with phase locked loop (PLL as voltage detection algorithm which output is used to determine decision logic algorithm for switching conditions. The results show that conditions of smart power system flow can be obtained based on voltage source selection in decision logic when fault condition occurs.

  5. Benchmarking of Constant Power Generation Strategies for Single-Phase Grid-Connected Photovoltaic Systems

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

    2018-01-01

    strategies based on: 1) a power control method (P-CPG), 2) a current limit method (I-CPG) and 3) the Perturb and Observe algorithm (P&O-CPG). However, the operational mode changes (e.g., from the maximum power point tracking to a CPG operation) will affect the entire system performance. Thus, a benchmarking...... of the presented CPG strategies is also conducted on a 3-kW single-phase grid-connected PV system. Comparisons reveal that either the P-CPG or I-CPG strategies can achieve fast dynamics and satisfactory steady-state performance. In contrast, the P&O-CPG algorithm is the most suitable solution in terms of high...... active power control methods are required. As a cost-effective solution to avoid overloading, a Constant Power Generation (CPG) control scheme by limiting the feed-in power has been introduced into the currently active grid regulations. In order to achieve a CPG operation, this paper presents three CPG...

  6. Benchmarking of Constant Power Generation Strategies for Single-Phase Grid-Connected Photovoltaic Systems

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

    2016-01-01

    strategies based on: 1) a power control (P-CPG), 2) a current limit method (I-CPG) and 3) the Perturb and Observe algorithm (P&O-CPG). However, the operational mode changes (e.g., from the maximum power point tracking to a CPG operation) will affect the entire system performance. Thus, a benchmarking...... of the proposed CPG strategies is also conducted on a 3-kW single-phase grid-connected PV system. Comparisons reveal that either the P-CPG or I-CPG strategies can achieve fast dynamics and satisfactory steady-state performance. In contrast, the P&OCPG algorithm is the most suitable solution in terms of high...... active power control methods are required. As a cost-effective solution to avoid overloading, a Constant Power Generation (CPG) control scheme by limiting the feed-in power has been introduced into the currently active grid regulations. In order to achieve a CPG operation, this paper proposes three CPG...

  7. Low-Voltage Ride-Through Capability of a Single-Stage Single-Phase Photovoltaic System Connected to the Low-Voltage Grid

    Directory of Open Access Journals (Sweden)

    Yongheng Yang

    2013-01-01

    Full Text Available The progressive growing of single-phase photovoltaic (PV systems makes the Distribution System Operators (DSOs update or revise the existing grid codes in order to guarantee the availability, quality, and reliability of the electrical system. It is expected that the future PV systems connected to the low-voltage grid will be more active with functionalities of low-voltage ride-through (LVRT and the grid support capability, which is not the case today. In this paper, the operation principle is demonstrated for a single-phase grid-connected PV system in a low-voltage ride-through operation in order to map future challenges. The system is verified by simulations and experiments. Test results show that the proposed power control method is effective and the single-phase PV inverters connected to low-voltage networks are ready to provide grid support and ride-through voltage fault capability with a satisfactory performance based on the grid requirements for three-phase renewable energy systems.

  8. A Current-Forced Line-Commutated Inverter for Single-Phase Grid-Connected Photovoltaic Generation Systems

    Directory of Open Access Journals (Sweden)

    UNLU, M.

    2015-05-01

    Full Text Available A simple power electronic interface based on the line-commutated inverter (LCI has been developed in order to inject sinusoidal current to the grid for single-phase grid-connected photovoltaic (PV energy generation systems. The proposed inverter facilitates controlling the injecting/grid current with a controllable power factor in contrast to the conventional LCI system. It is achieved that the total harmonic distortion (THD of the injecting currents for the different firing angles/power factors and reference currents is about 5% or less than 5%. Thus, the grid-connected standards for injecting current are satisfied without filter equipment unlike the conventional LCI system. The proposed system has been built in MATLAB/Simulink and examined experimentally on PV array of 160 W. The simulation and experimental results are better performance than the conventional line-commutated inverter methods reported in the literature. The proposed LCI has a simple and robust structure, and it can be easily synchronized with grid thanks to self-latching property of SCRs. Therefore, it is a good alternative for the power transferring from PV panels to the utility grid in grid-connected PV systems.

  9. Harmonic Instability Analysis of Single-Phase Grid Connected Converter using Harmonic State Space (HSS) modeling method

    DEFF Research Database (Denmark)

    Kwon, Jun Bum; Wang, Xiongfei; Bak, Claus Leth;

    2015-01-01

    and impedance from other renewable energy sources are not taken carefully into account in the installation and design. However, this may bring an unknown harmonic instability into the multiple power sourced system and also make the analysis difficult due to the complexity of the grid network. This paper......The increasing number of renewable energy sources at the distribution grid is becoming a major issue for utility companies, since the grid connected converters are operating at different operating points due to the probabilistic characteristics of renewable energy. Besides, typically, the harmonics...... proposes a new model of a single phase grid connected renewable energy source using the Harmonic State Space modeling approach, which is able to identify such problems and the model can be extended to be applied in the multiple connected converter analysis. The modeling results show the different harmonic...

  10. Harmonic Instability Analysis of Single-Phase Grid-Connected Converter using Harmonic State-space (HSS) modeling method

    DEFF Research Database (Denmark)

    Kwon, Jun Bum; Wang, Xiongfei; Blaabjerg, Frede;

    2016-01-01

    and impedance from other renewable energy sources are not taken carefully into account in the installation and design of the systems. It can bring an unknown harmonic instability into a multiple power sourced system and makes the analysis difficult due to the complexity of the grid network. This paper proposes......The increasing number of renewable energy sources in the distribution grid is becoming a major issue for utility companies since grid-connected converters are operating at different operating points due to the probabilistic characteristics of the renewable energy. Usually, the harmonics...... a new model of a single-phase grid-connected renewable energy source by using the Harmonic State-space Modeling approach, which can identify such problems. The model can be extended to a multiple connected converter analysis. The modeling results show the harmonic impedance matrixes, which represent...

  11. A Novel Neural Network Vector Control for Single-Phase Grid-Connected Converters with L, LC and LCL Filters

    OpenAIRE

    Xingang Fu; Shuhui Li

    2016-01-01

    This paper investigates a novel recurrent neural network (NN)-based vector control approach for single-phase grid-connected converters (GCCs) with L (inductor), LC (inductor-capacitor) and LCL (inductor-capacitor-inductor) filters and provides their comparison study with the conventional standard vector control method. A single neural network controller replaces two current-loop PI controllers, and the NN training approximates the optimal control for the single-phase GCC system. The Levenberg...

  12. Design and Tuning of a Modified Power-Based PLL for Single-Phase Grid-Connected Power Conditioning Systems

    DEFF Research Database (Denmark)

    Golestan, Saeed; Monfared, Mohammad; D. Freijedo, Francisco

    2012-01-01

    One of the most important aspects for the proper operation of the single-phase grid-tied power-conditioning systems is the synchronization with the utility grid. Among various synchronization techniques, phase locked loop (PLL) based algorithms have found a lot of interest for the advantages...... they present. Typically, the single-phase PLLs use a sinusoidal multiplier as the phase detector (PD). These PLLs are generally referred to as the power-based PLL (pPLL). In this paper, the drawbacks associated with the pPLL technique (i.e., the sensitivity to the grid voltage variations, and the double....... The effectiveness of the proposed method is evaluated through a detailed mathematical analysis. A systematic design method to fine-tune the PLL parameters is then suggested, which guarantees a fast transient response, a high disturbance rejection capability, and a robust performance. Finally, the simulation...

  13. Influence of the spatial resolution on fine-scale features in DNS of turbulence generated by a single square grid

    CERN Document Server

    Laizet, S; Vassilicos, J C

    2014-01-01

    We focus in this paper on the effect of the resolution of Direct Numerical Simulations (DNS) on the spatio-temporal development of the turbulence downstream of a single square grid. The aims of this study are to validate our numerical approach by comparing experimental and numerical one-point statistics downstream of a single square grid and then investigate how the resolution is impacting the dynamics of the flow. In particular, using the Q-R diagram, we focus on the interaction between the strain-rate and rotation tensors, the symmetric and skew-symmetric parts of the velocity gradient tensor respectively. We first show good agreement between our simulations and hot-wire experiment for one-point statistics on the centreline of the single square grid. Then, by analysing the shape of the Q-R diagram for various streamwise locations, we evaluate the ability of under-resolved DNS to capture the main features of the turbulence downstream of the single square grid.

  14. Single-Board-Computer-Based Traffic Generator for a Heterogeneous and Hybrid Smart Grid Communication Network

    OpenAIRE

    Do Nguyet Quang; Ong Hang See; Lai Lee Chee; Che Yung Xuen; Shashiteran A/L. Karuppiah

    2014-01-01

    In smart grid communication implementation, network traffic pattern is one of the main factors that affect the system’s performance. Examining different traffic patterns in smart grid is therefore crucial when analyzing the network performance. Due to the heterogeneous and hybrid nature of smart grid, the type of traffic distribution in the network is still unknown. The traffic that popularly used for simulation and analysis no longer reflects the real traffic in a multi-technology and bi-dir...

  15. A Single Phase Seven-level Grid-connected inverter Based On Three Reference SPWM Strategy

    DEFF Research Database (Denmark)

    Sun, Bo; Wu, Fengjiang; Dragicevic, Tomislav

    2014-01-01

    This paper introduces a seven level grid connected system based on the Three Reference SPWM (TRSPWM) strategy and a Quasi PR current controller has a good output performance with a fast response and compensation for the low order harmonics in grid. With the multilevel output voltage and a high tr...... tracking current strategy with a low-order harmonic compensator, the grid connected system could operate properly in a polluted grid with low order harmonic. The simulation based on MATLAB verify the proposed the accuracy and feasibility of the proposed scheme....

  16. Grid Search in Stellar Parameters: a software for spectrum analysis of single stars and binary systems

    CERN Document Server

    Tkachenko, Andrew

    2015-01-01

    The currently operating space missions, as well as those that will be launched in the near future, (will) deliver high-quality data for millions of stellar objects. Since the majority of stellar astrophysical applications still (at least partly) rely on spectroscopic data, an efficient tool for the analysis of medium- to high-resolution spectroscopy is needed. We aim at developing an efficient software package for the analysis of medium- to high-resolution spectroscopy of single stars and those in binary systems. The major requirements are that the code has a high performance, represents the state-of-the-art analysis tool, and provides accurate determinations of atmospheric parameters and chemical compositions for different types of stars. We use the method of atmosphere models and spectrum synthesis, which is one of the most commonly used approaches for the analysis of stellar spectra. Our Grid Search in Stellar Parameters (GSSP) code makes use of the OpenMPI implementation, which makes it possible to run in...

  17. Inverter Anti-Islanding with Advanced Grid Support in Single- and Multi-Inverter Islands

    Energy Technology Data Exchange (ETDEWEB)

    Hoke, Andy

    2016-08-16

    As PV and other DER systems are connected to the grid at increased penetration levels, island detection may become more challenging for two reasons: 1. In islands containing many DERs, active inverter-based anti-islanding methods may have more difficulty detecting islands because each individual inverter's efforts to detect the island may be interfered with by the other inverters in the island. 2. The increasing numbers of DERs are leading to new requirements that DERs ride through grid disturbances and even actively try to regulate grid voltage and frequency back towards nominal operating conditions. These new grid support requirements may directly or indirectly interfere with anti-islanding controls. This report describes a series of tests designed to examine the impacts of both grid support functions and multi-inverter islands on anti-islanding effectiveness.

  18. Single-Grid-Pair Fourier Telescope for Imaging in Hard-X Rays and gamma Rays

    Science.gov (United States)

    Campbell, Jonathan

    2008-01-01

    This instrument, a proposed Fourier telescope for imaging in hard-x rays and gamma rays, would contain only one pair of grids made of an appropriate radiation-absorpting/ scattering material, in contradistinction to multiple pairs of such as grids in prior Fourier x- and gamma-ray telescopes. This instrument would also include a relatively coarse gridlike image detector appropriate to the radiant flux to be imaged. Notwithstanding the smaller number of grids and the relative coarseness of the imaging detector, the images produced by the proposed instrument would be of higher quality.

  19. Pencil-Beam Single-point-fed Dirac Leaky-Wave Antenna on a Transmission-Line Grid

    CERN Document Server

    Dorrah, Ayman H

    2016-01-01

    Leaky-wave antennas (LWAs) are widely used as single-point-fed linear antenna arrays. The extension of LWAs to 2D implies that they can be used as single-point-fed 2D antenna arrays without requiring a complex feeding network. However, generating a pencil beam from 2D LWAs is not straightforward and due care has to be taken for the design of the LWA. On the other hand, transmission-line (TL) grids have demonstrated interesting behaviors, such as an effective negative refractive index and growing of evanescent waves. In this paper, a singlepoint-fed TL-grid 2D Dirac leaky-wave antenna (DLWA) design is proposed that generates a pencil beam at both broadside and slightly tilted angles. The TL-grid unit cell is analytically treated in light of its scattering and impedance matrices. The optimized TL-grid unit cell is shown to exhibit a closed bandgap in the dispersion relation which is also linearly varying with frequency (hence it is a DLWA). The proposed 2D DLWA design is fabricated and the experimental results ...

  20. Grid search in stellar parameters: a software for spectrum analysis of single stars and binary systems

    Science.gov (United States)

    Tkachenko, A.

    2015-09-01

    Context. The currently operating space missions, as well as those that will be launched in the near future, will deliver high-quality data for millions of stellar objects. Since the majority of stellar astrophysical applications still (at least partly) rely on spectroscopic data, an efficient tool for the analysis of medium- to high-resolution spectroscopy is needed. Aims: We aim at developing an efficient software package for the analysis of medium- to high-resolution spectroscopy of single stars and those in binary systems. The major requirements are that the code should have a high performance, represent the state-of-the-art analysis tool, and provide accurate determinations of atmospheric parameters and chemical compositions for different types of stars. Methods: We use the method of atmosphere models and spectrum synthesis, which is one of the most commonly used approaches for the analysis of stellar spectra. Our Grid Search in Stellar Parameters (gssp) code makes use of the Message Passing Interface (OpenMPI) implementation, which makes it possible to run in parallel mode. The method is first tested on the simulated data and is then applied to the spectra of real stellar objects. Results: The majority of test runs on the simulated data were successful in that we were able to recover the initially assumed sets of atmospheric parameters. We experimentally find the limits in signal-to-noise ratios of the input spectra, below which the final set of parameters is significantly affected by the noise. Application of the gssp package to the spectra of three Kepler stars, KIC 11285625, KIC 6352430, and KIC 4931738, was also largely successful. We found an overall agreement of the final sets of the fundamental parameters with the original studies. For KIC 6352430, we found that dependence of the light dilution factor on wavelength cannot be ignored, as it has a significant impact on the determination of the atmospheric parameters of this binary system. Conclusions: The

  1. Implementation and evaluation of a monthly water balance model over the US on an 800 m grid

    Science.gov (United States)

    Hostetler, S. W.; Alder, J. R.

    2016-12-01

    We simulate the 1950-2010 water balance for the conterminous U.S. (CONUS) with a monthly water balance model (MWBM) using the 800 m Parameter-elevation Regression on Independent Slopes Model (PRISM) data set as model input. We employed observed snow and streamflow data sets to guide modification of the snow and potential evapotranspiration components in the default model and to evaluate model performance. Based on various metrics and sensitivity tests, the modified model yields reasonably good simulations of seasonal snowpack in the West (range of bias of ±50 mm at 68% of 713 SNOTEL sites), the gradients and magnitudes of actual evapotranspiration, and runoff (median correlation of 0.83 and median Nash-Sutcliff efficiency of 0.6 between simulated and observed annual time series at 1427 USGS gage sites). The model generally performs well along the Pacific Coast, the high elevations of the Basin and Range and over the Midwest and East, but not as well over the dry areas of the Southwest and upper Plains regions due, in part, to the apportioning of direct versus delayed runoff. Sensitivity testing and application of the MWBM to simulate the future water balance at four National Parks when driven by 30 climate models from the Climate Model Intercomparison Program Phase 5 (CMIP5) demonstrate that the model is useful for evaluating first-order, climate driven hydrologic change on monthly and annual time scales.

  2. Harnessing the hybrid power supply systems of utility grid and photovoltaic panels at retrofit residential single family building in Medan

    Science.gov (United States)

    Pangaribuan, A. B.; Rahmat, R. F.; Lidya, M. S.; Zálešák, M.

    2017-01-01

    The paper describes improvisation mode of energy supply source by collaboration between national utility grid as represented by fossil fuels and PV as independent renewable power resource in order to aim the energy consumptions efficiently in retrofit single family house. In this case, one existing single family house model in Medan, Indonesia was observed for the possibility of future refurbishment. The eco-design version of the house model and prediction analyses regarding nearby potential renewable energy resource (solar system) had been made using Autodesk Revit MEP 2015, Climate Consultant 6.0 and Green Building Studio Analysis. Economical evaluation of using hybrid power supply is discussed as well.

  3. Reliable Grid Condition Detection and Control of Single-Phase Distributed Power Generation Systems

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai

    The constant growth of Distributed Power Generation Systems (DPGS) presents an efficient and economic way of generating electricity closer to the load(s). The DPGS can contribute to an efficient and renewable electricity future by potentially: increasing the use of renewable sources of energy......; improving the efficiency of the electricity system by reducing transmission and distribution losses; improving the security of the electricity supply through increased diversity of supply and reduced vulnerability to simultaneous system failures. However, the new trend of using DPGS comes also with a suite...... of new challenges. One of the challenges is the interaction between the DPGS and the utility grid. As a consequence, grid interconnection requirements applying to distributed generation are continuously updated in order to maintain the quality and the stability of the utility grid. The new upcoming...

  4. CERES Monthly TOA and SRB Averages (SRBAVG) data in HDF-EOS Grid (CER_SRBAVG_Terra-FM1-MODIS_Edition2D)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    The Monthly TOA/Surface Averages (SRBAVG) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SRBAVG is also produced for combinations of scanner instruments. The monthly average regional flux is estimated using diurnal models and the 1-degree regional fluxes at the hour of observation from the CERES SFC product. A second set of monthly average fluxes are estimated using concurrent diurnal information from geostationary satellites. These fluxes are given for both clear-sky and total-sky scenes and are spatially averaged from 1-degree regions to 1-degree zonal averages and a global average. For each region, the SRBAVG also contains hourly average fluxes for the month and an overall monthly average. The cloud properties from SFC are column averaged and are included on the SRBAVG. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-02-01; Stop_Date=2004-05-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 month; Temporal_Resolution_Range=Monthly - < Annual].

  5. CERES Monthly TOA and SRB Averages (SRBAVG) data in HDF-EOS Grid (CER_SRBAVG_Terra-FM1-MODIS_Edition2C)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    The Monthly TOA/Surface Averages (SRBAVG) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SRBAVG is also produced for combinations of scanner instruments. The monthly average regional flux is estimated using diurnal models and the 1-degree regional fluxes at the hour of observation from the CERES SFC product. A second set of monthly average fluxes are estimated using concurrent diurnal information from geostationary satellites. These fluxes are given for both clear-sky and total-sky scenes and are spatially averaged from 1-degree regions to 1-degree zonal averages and a global average. For each region, the SRBAVG also contains hourly average fluxes for the month and an overall monthly average. The cloud properties from SFC are column averaged and are included on the SRBAVG. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-02-01; Stop_Date=2003-02-28] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 month; Temporal_Resolution_Range=Monthly - < Annual].

  6. CERES Monthly TOA and SRB Averages (SRBAVG) data in HDF-EOS Grid (CER_SRBAVG_TRMM-PFM-VIRS_Edition2B)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    The Monthly TOA/Surface Averages (SRBAVG) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SRBAVG is also produced for combinations of scanner instruments. The monthly average regional flux is estimated using diurnal models and the 1-degree regional fluxes at the hour of observation from the CERES SFC product. A second set of monthly average fluxes are estimated using concurrent diurnal information from geostationary satellites. These fluxes are given for both clear-sky and total-sky scenes and are spatially averaged from 1-degree regions to 1-degree zonal averages and a global average. For each region, the SRBAVG also contains hourly average fluxes for the month and an overall monthly average. The cloud properties from SFC are column averaged and are included on the SRBAVG. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-02-01; Stop_Date=2000-03-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 month; Temporal_Resolution_Range=Monthly - < Annual].

  7. CERES Monthly TOA and SRB Averages (SRBAVG) data in HDF-EOS Grid (CER_SRBAVG_Terra-FM2-MODIS_Edition2D)

    Science.gov (United States)

    Wielicki, Bruce A. (Principal Investigator)

    The Monthly TOA/Surface Averages (SRBAVG) product contains a month of space and time averaged Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SRBAVG is also produced for combinations of scanner instruments. The monthly average regional flux is estimated using diurnal models and the 1-degree regional fluxes at the hour of observation from the CERES SFC product. A second set of monthly average fluxes are estimated using concurrent diurnal information from geostationary satellites. These fluxes are given for both clear-sky and total-sky scenes and are spatially averaged from 1-degree regions to 1-degree zonal averages and a global average. For each region, the SRBAVG also contains hourly average fluxes for the month and an overall monthly average. The cloud properties from SFC are column averaged and are included on the SRBAVG. [Location=GLOBAL] [Temporal_Coverage: Start_Date=1998-02-01; Stop_Date=2004-05-31] [Spatial_Coverage: Southernmost_Latitude=-90; Northernmost_Latitude=90; Westernmost_Longitude=-180; Easternmost_Longitude=180] [Data_Resolution: Latitude_Resolution=1 degree; Longitude_Resolution=1 degree; Horizontal_Resolution_Range=100 km - < 250 km or approximately 1 degree - < 2.5 degrees; Temporal_Resolution=1 month; Temporal_Resolution_Range=Monthly - < Annual].

  8. A Novel Neural Network Vector Control for Single-Phase Grid-Connected Converters with L, LC and LCL Filters

    Directory of Open Access Journals (Sweden)

    Xingang Fu

    2016-04-01

    Full Text Available This paper investigates a novel recurrent neural network (NN-based vector control approach for single-phase grid-connected converters (GCCs with L (inductor, LC (inductor-capacitor and LCL (inductor-capacitor-inductor filters and provides their comparison study with the conventional standard vector control method. A single neural network controller replaces two current-loop PI controllers, and the NN training approximates the optimal control for the single-phase GCC system. The Levenberg–Marquardt (LM algorithm was used to train the NN controller based on the complete system equations without any decoupling policies. The proposed NN approach can solve the decoupling problem associated with the conventional vector control methods for L, LC and LCL-filter-based single-phase GCCs. Both simulation study and hardware experiments demonstrate that the neural network vector controller shows much more improved performance than that of conventional vector controllers, including faster response speed and lower overshoot. Especially, NN vector control could achieve very good performance using low switch frequency. More importantly, the neural network vector controller is a damping free controller, which is generally required by a conventional vector controller for an LCL-filter-based single-phase grid-connected converter and, therefore, can overcome the inefficiency problem caused by damping policies.

  9. Single-pass albumin dialysis in a child aged six months with phenobarbital poisoning.

    Science.gov (United States)

    Kıhtır, Hasan Serdar; Yıldırım, Hamdi Murat; Yeşilbaş, Osman; Duramaz, Burcu Bursal; Şevketoğlu, Esra

    2016-12-01

    A girl aged six months was hospitalized because of resistant seizures and was discharged with phenobarbital and carbamazepine therapy. She was admitted to a state hospital with symptoms of inability to waken and difficulty in breathing. It was learned that phenobarbital had been used incorrectly and the patient was sent to our pediatric intensive care unit because of severe phenobarbital overdose. The decision was taken for hemodialysis. Single-pass albumin dialysis was planned because phenobarbital can bind to high levels of plasma protein. The process was undertaken with 1% albumin-containing dialysate, which was prepared manually. After 6 hours of dialysis, the phenobarbital blood level measured 62 mcg/mL (>140 mcg/mL on admission) and the patient's clinical findings were markedly regressed. There are no case reports about phenobarbital overdose treated with single-pass albumin dialysis in the literature. We conclude that single-pass albumin dialysis may be a useful treatment, especially with intoxications of drugs that bind protein at high levels.

  10. Two-stage single-phase grid-connected photovoltaic system with reduced complexity

    Science.gov (United States)

    da Silva, Cintia S.; Motta, Filipe R.; Tofoli, Fernando L.

    2011-06-01

    This article presents a grid-connected photovoltaic (PV) system using the classical DC-DC buck converter, which is responsible for stepping down the resulting voltage from several series-connected panels. Besides, the structure provides high power factor operation by injecting a quasi-sinusoidal current into the grid, with near no displacement in relation to the line voltage at the point of common coupling among the PV system and the loads. A CSI employing thyristors is cascaded with the DC-DC stage so that AC voltage results. The inverter output voltage level is adjusted by using a low-frequency transformer, which also provides galvanic isolation. The proposed system is described as mathematical approach and design guidelines are presented, providing an overview of the topology. An experimental prototype is also implemented, and relevant results to validate the proposal are discussed.

  11. A Single-Phase Voltage-Controlled Grid-Connected Photovoltaic System With Power Quality Conditioner Functionality

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Liserre, Marco; Mastromauro, R. A.

    2009-01-01

    Future ancillary services provided by photovoltaic (PV) systems could facilitate their penetration in power systems. Also low power PV systems can be designed to improve the power quality. This paper presents a single-phase photovoltaic system that provides grid voltage support and compensation...... of harmonic distortion at the point of common coupling (PCC) thanks to a repetitive controller. The power provided by the PV panels is controlled by a Maximum Power Point Tracking (MPPT) algorithm based on the incremental conductance method specifically modified to control the phase of the PV inverter voltage...

  12. General Unified Integral Controller with Zero Steady-State Error for Single-Phase Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Guerrero, Josep M.

    2016-01-01

    the steady-state error suppression with no need of additional complex control algorithms such as the synchronous reference frame transformation. Five alternative implementation methods are comparatively evaluated from the viewpoint of the steady-state and dynamic responses. Further, the theoretical analysis......Current regulation is crucial for operating single-phase grid-connected inverters. The challenge of the current controller is how to fast and precisely tracks the current with zero steady-state error. This paper proposes a novel feedback mechanism for the conventional PI controller. It allows...

  13. LLCL-Filter Based Single-Phase Grid-Tied Aalborg Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; Feng, Shuangshuang; Ji, Junhao

    2014-01-01

    The Aalborg Inverter is a new type of high efficient DC/AC grid-tied inverter, where the input DC voltage can vary in a wide range. Compared with the LCL-filter, the LLCL-filter can save the total inductance for the conventional voltage source inverter. In this paper, an LLCL-filter based Aalborg...... Inverter is proposed and its character is illustrated through the small signal analysis in both “Buck” and “Buck-Boost” mode. From the modeling, it can be seen that the resonant inductor in the capacitor loop has not brought extra control difficulties, whereas more inductance in the power loop can be saved...

  14. An Adaptive Quadrature Signal Generation Based Single-Phase Phase-Locked Loop for Grid-Connected Applications

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Abusorrah, Abdullah

    2017-01-01

    The quadrature signal generation based phase-locked loops (QSG-PLLs) are highly popular for synchronization purposes in single-phase systems. The main difference among these PLLs often lies in the technique they use for creating the fictitious quadrature component. One of the easiest QSG approaches...... is delaying the original single-phase signal by a quarter of a cycle. The PLL with such QSG technique is often called the transfer delay based PLL (TD-PLL). The TD-PLL benefits from a simple structure, rather fast dynamic response, and a good detection accuracy when the grid frequency is at its nominal value......, but it suffers from a phase offset error and double frequency oscillatory error in the estimated phase and frequency in the presence of frequency drifts. In this paper, a simple yet effective approach to remove the aforementioned errors of the TD-PLL is proposed. The resultant PLL structure is called...

  15. Trends in life science grid: from computing grid to knowledge grid

    OpenAIRE

    Konagaya Akihiko

    2006-01-01

    Abstract Background Grid computing has great potential to become a standard cyberinfrastructure for life sciences which often require high-performance computing and large data handling which exceeds the computing capacity of a single institution. Results This survey reviews the latest grid technologies from the viewpoints of computing grid, data grid and knowledge grid. Computing grid technologies have been matured enough to solve high-throughput real-world life scientific problems. Data grid...

  16. Modeling Single-Phase PV HB-ZVR Inverter Connected to Grid

    DEFF Research Database (Denmark)

    Guo, Yougui; Zeng, Ping; Zhu, Jieqiong;

    2011-01-01

    PLECS is used to model the PV H-bridge zero voltage rectifier (HB-ZVR) inverter connected to grid and good results are obtained. First, several common topologies of PV inverters are introduced. Then the unipolar PWM control strategy is described for PV HB-ZVR inverter. Third, PLECS is briefly...... introduced. Fourth, the modeling of PV HB-ZVR inverter is presented with PLECS. Finally, a series of simulations are carried out. The simulation results tell us PLECS is very powerful tool to real power circuits and it is very easy to simulate LCL filter. They have also verified that the unipolar PWM control...... strategy is feasible to control the PV HB-ZVR inverter....

  17. Scintigraphy at 3 months after single lung transplantation and observations of primary graft dysfunction and lung function

    DEFF Research Database (Denmark)

    Belmaati, Esther Okeke; Iversen, Martin; Kofoed, Klaus F;

    2012-01-01

    procedure 3 months after single lung transplantation (SLTX). A total of 41 patients were included in the study: 20 women and 21 men with the age span of patients at transplantation being 38-66 years (mean ± SD: 54.2 ± 6.0). Patient records also included lung function tests and chest X-ray images. We found......, and to investigate whether scintigraphic findings at 3 months were predictive for the outcome at 12 months in relation to primary graft dysfunction (PGD) and lung function. A retrospective study was carried out on all patients who prospectively and consecutively were referred for a routine lung scintigraphy...... no significant correlation between lung function distribution at 3 months and PGD at 72 h. There was also no significant correlation between PGD scores at 72 h and lung function at 6 and 12 months. The same applied to scintigraphic scores for heterogeneity at 3 months compared with lung function at 6 and 12...

  18. 400 MW grid connection to the Anholt offshore wind farm in a single 220 kV cable system

    Energy Technology Data Exchange (ETDEWEB)

    Kvarts, Thomas [Energinet.dk (Denmark); Bailleul, March; Douima, Youssef; Petitot, Francois [General Cable Group, Silec, Cachan (France); Domingo, Jose M. [General Cable Group (Spain); Jensen, Anders; Salwin, Sven T. [nkt cables (Denmark)

    2011-07-01

    In 2012, the so far largest wind farm in Denmark, Anholt offshore wind farm, will bring 400 MW more electrical power to Denmark. To that effect, Energinet.dk, Denmark's transmission system operator, will install and operate an 85-km-long grid connection from the Anholt platform to the Danish electricity transmission grid. This connection is composed of: (1) a single 24 km 245 kV submarine, 3 core cable, delivered and installed by nkt cables, and (2) a 60 km 245 kV underground cable system, delivered by the General Cable group. (3) an offshore transformer platform. (4) reactive compensation and transformation onshore. This aim of this paper is to present the characteristics of this project, the first at 245 kV in Denmark, and one of the first 245 kV 3 core submarine cables worldwide. We will first discuss the reasons that prevailed in defining the link's design: routes, voltage, cables dimensioning, impact of capitalized losses etc. Then, the submarine and underground cable systems' characteristics and necessary type test are presented. Finally, we present an overview of the actual implementation of each solution. (orig.)

  19. Local thermodynamics of the water molecules around single- and double-stranded DNA studied by grid inhomogeneous solvation theory

    Science.gov (United States)

    Nakano, Miki; Tateishi-Karimata, Hisae; Tanaka, Shigenori; Tama, Florence; Miyashita, Osamu; Nakano, Shu-ichi; Sugimoto, Naoki

    2016-09-01

    Thermodynamic properties of water molecules around single- and double-stranded DNAs (ssDNAs and dsDNAs) with different sequences were investigated using grid inhomogeneous solvation theory. Free energies of water molecules solvating the minor groove of dsDNAs are lower than those near ssDNAs, while water molecules should be released during the formation of dsDNA. Free energies of water molecules around dsDNA are lower than those around ssDNA even in the second and third hydration shells. Our findings will help to clarify the role of water molecules in the formation of dsDNA from ssDNAs, thus facilitating the designs of drugs or nanomaterials using DNA.

  20. Fuzzy Logic Controlling of a Single Phase Seven-Level Grid-Connected Inverter for Photovoltaic system

    Directory of Open Access Journals (Sweden)

    Siva GanaVara Prasad P., Amrutha Veena Chandrapati, Navyata Yesodha Rao K., Lakshmi Prasanth K.

    2014-05-01

    Full Text Available This paper proposes fuzzy logic controller based a single-phase seven-level inverter for grid-connected photovoltaic systems, with a novel pulse width-modulation (PWM control scheme. Three reference signals produces from fuzzy logic controller which are identical to each other are going to compare with the amplitude of the triangular carrier signal. The inverter is capable of producing seven levels( Vab = Vdc Vab = 2Vdc/3 Vab = Vdc/3 Vab = 0 Vab = −V dc/3 Vab= − 2Vdc/3 Vab = −V dc of output-voltage levels from the dc supply voltage. The total harmonic distortion is reduces by this control strategy. The proposed system was verified through simulation.

  1. Control scheme towards enhancing power quality and operational efficiency of single-phase two-stage grid-connected photovoltaic systems

    Directory of Open Access Journals (Sweden)

    Mahmoud Salem

    2015-12-01

    Full Text Available Achieving high reliable grid-connected photovoltaic (PV systems with high power quality and high operation efficiency is highly required for distributed generation units. A double grid-frequency voltage ripple is found on the dc-link voltage in single-phase photovoltaic grid-connected systems due to the unbalance of the instantaneous dc input and ac output powers. This voltage ripple has undesirable effects on the power quality and operational efficiency of the whole system. Harmonic distortion in the injected current to the grid is one of the problems caused by this double grid-frequency voltage ripple. The double grid frequency ripple propagates to the PV voltage and current which disturb the extracted maximum power from the PV array. This paper introduces intelligent solutions towards mitigate the side effects of the double grid-frequency voltage ripple on the transferred power quality and the operational efficiency of single-phase two-stage grid-connected PV system. The proposed system has three control loops: MPPT control loop, dc-link voltage control loop and inverter current control loop. Solutions are introduced for all the three control loops in the system. The current controller cancels the dc-link voltage effect on the total harmonic distortion of the output current. The dc-link voltage controller is designed to generate a ripple free reference current signal that leads to enhance the quality of the output power. Also a modified MPPT controller is proposed to optimize the extracted power from the PV array. Simulation results show that higher injected power quality is achieved and higher efficiency of the overall system is realized.

  2. Robust Two Degrees-of-freedom Single-current Control Strategy for LCL-type Grid-Connected DG System under Grid-Frequency Fluctuation and Grid-impedance Variation

    DEFF Research Database (Denmark)

    Zhou, Leming; Chen, Yandong; Luo, An

    2016-01-01

    For LCL-type grid-connected distributed generation(DG) system, the grid-frequency fluctuation and grid-impedance variation affect the active/reactive power control accuracy and resonance peak suppression respectively, which would reduce the system robustness. In this paper, a robust two degrees-of-freedom......-state performances. The stability margin and dynamic response of the overall system are analyzed in detail, and the proper parameters are selected without complicated trial. Finally, Simulation and experimental results verify the proposed control and design strategies....

  3. Reducing Electromagnetic Interference in a Grid Tied Single Phase Power Inverter

    Science.gov (United States)

    2016-09-01

    Unipolar PWM. Source : [3]. ...............................7 Figure 6. Common Mode Emissions in a Single-Phase Inverter...pulse-width modulation transforms a DC source voltage into an AC sine wave. Sending gating signals to the H- bridge at a predetermined frequency...Voltage Wave Forms with Bipolar PWM. Source : [3]. Figure 3. Table 1. Logic Table for Bipolar PWM. Adapted from [3]. vcontrol > vtriangle Gate 1

  4. Stability of Child Behavioral Style in the First 30 Months of Life: Single Timepoint and Aggregated Measures

    Science.gov (United States)

    Parade, Stephanie H.; Dickstein, Susan; Schiller, Masha; Hayden, Lisa; Seifer, Ronald

    2015-01-01

    The current study examined the stability of temperament over time. Observers and mothers rated child behavior at eight timepoints across three assessment waves (8, 15, and 30 months of age). Internal consistency reliability of aggregates of the eight observer reports and eight mother reports were high. When considering single timepoint…

  5. Stability of Child Behavioral Style in the First 30 Months of Life: Single Timepoint and Aggregated Measures

    Science.gov (United States)

    Parade, Stephanie H.; Dickstein, Susan; Schiller, Masha; Hayden, Lisa; Seifer, Ronald

    2015-01-01

    The current study examined the stability of temperament over time. Observers and mothers rated child behavior at eight timepoints across three assessment waves (8, 15, and 30 months of age). Internal consistency reliability of aggregates of the eight observer reports and eight mother reports were high. When considering single timepoint…

  6. 单相高可靠并网逆变器电路拓扑%Single-phase high-reliability grid-connected inverter topologies

    Institute of Scientific and Technical Information of China (English)

    姚志垒; 肖岚

    2013-01-01

    A family of single-phase high-reliability grid-connected inverter topology is proposed to solve the shoot-through problem in conventional bridge-type grid-connected inverters. The proposed grid-connected inverters are deduced from the high-reliability cells. The operating principles of the proposed high-reliability grid-connected inverters with bipolar and unipolar modulations are illustrated. The constituent principle of the high-reliability grid-connected inverters is concluded. The simulation results of a dual-buck full-bridge grid-connected inverter with unipolar modulation verify the theoretical analysis. The comparison between the high-reliability grid-connected inverter and traditional grid-connected inverter shows that the dual-buck half-bridge grid-connected inverter is suitable for 110~120 V grid-voltage applications and the full-bridge type high-reliability grid-connected inverters are promising in 220~240 V grid-voltage applications.%针对传统桥式并网逆变器存在桥臂功率开关管的直通问题,提出了一族单相高可靠并网逆变器电路拓扑。所提并网逆变器是由高可靠性单元相互组合而成。分析了双极性和单极性调制高可靠并网逆变器的工作原理,归纳出了高可靠并网逆变器的构成原则。以单极性双降压全桥并网逆变器为例进行了仿真验证。比较分析了传统并网逆变器和所提高可靠并网逆变器。分析结果表明:双降压半桥并网逆变器适合110~120 V电网电压场合,而全桥型高可靠并网逆变器适合220~240 V电网电压场合。

  7. A Frequency Locked Loop Grid Synchronization Method of Single-phase Grid-connected PV Inverter Under Weak Grid%弱电网下单相光伏并网逆变器锁频环同步方法

    Institute of Scientific and Technical Information of China (English)

    刘桂花; 曹小娇; 王卫

    2015-01-01

    One of the main electrical characteristics of weak grid is the high grid impedance, which will easily lead to grid voltage waveform distortion. Distorted grid voltage can resultin deviation or failure of the phase-locked loop of photovoltaic (PV) inverter, and power quality will deteriorate. In order to tackle this problem, targeting on the LC-type PV inverter,a synchronization method is proposed based on the second order generalized integrator frequency locked loop (SOGI-FLL). Initially, the impact of various grid states, especially the weak grid, on the inverter is analyzed. Then the operation principle of SOGI-FLL and its implementation method are set forth in detail. Simulation and experimental results demonstrate the validity of this synchronization method in grid voltage disturbance and zero-crossing oscillation. This synchronization method has strong robustness and adaptability for grid voltage changes. Compared with the conventional zero-crossing synchronization method, the SOGI-FLL synchronization method can improve the reliability of grid-connected PV inverters under weak grid.%弱电网的主要电气特性之一为高电网阻抗.高电网阻抗易导致电网电压波形畸变,畸变的电网电压会使光伏并网逆变器锁相环出现偏差甚至失效,并导致并网电能质量变差.针对这一问题,以LC型单相光伏并网逆变器为研究对象,提出采用基于2阶广义积分器锁频环(second order generalized integrator frequency locked loop,SOGI-FLL)同步方法来实现逆变器与弱电网的同步.在分析不同电网状态尤其是弱电网对逆变器影响的基础上,详细阐述SOGI-FLL的工作原理和实现方法.仿真和实验结果表明,该同步方法在电网电压扰动及过零点震荡情况下均可稳定可靠工作,对电网电压变化具有较强的鲁棒性和适应性,与传统过零同步方法相比,SOGI-FLL同步方法可提高弱电网下光伏并网逆变器的可靠性.

  8. Below the knee PTA in critical limb ischemia results after 12 months: Single center experience

    Energy Technology Data Exchange (ETDEWEB)

    Balzer, Joern O., E-mail: balzerjo@t-online.d [Dept. for Radiology and Nuclear medicine, Catholic Clinic Mainz, An der Goldgrube 11, Mainz 55131 (Germany); Khan, Verena [Dept. of Diagnostic and Interventional Radiology, Clinic Nurnberg North (Germany); Thalhammer, Axel; Vogl, Thomas J.; Lehnert, Thomas [Dept. of Diagnostic and Interventional Radiology, Univ. Clinic, Johann Wolfgang Goethe-University Frankfurt/Main (Germany)

    2010-07-15

    Purpose: Evaluation of angioplasty with bare metal stents in infrapopliteal occlusions or severe stenoses in patients with critical limb ischemia. Material and methods: Percutaneous stent angioplasty was performed in 58 limbs in 47 patients with critical limb ischemia (CLI) in Rutherford stage 4-6. Lesions with up to 5 cm in length with at least one patent vessel below the obstruction were treated. 121 bare metal stents (diameter of 2.5-4 mm; length of 18-38 mm) were implanted. Follow-up examinations were performed up to 12 months postinterventionally using clinical examination, ABI calculation, and color-coded duplex sonography. Patency rates were calculated on the basis of the Kaplan-Meier analysis. Results: Technical success was achieved in 100%. Minor complications (hematoma, distal emboli, vessel dissection) were documented in 5.17% (n = 3) limbs, respectively. The 3-month, 6-month, and 1-year primary patency rate was 93.0%, 78.9% and 66.7%, respectively. 86.9% of the lesions healed postinterventionally. The cumulative limb salvage rate was 96.6%. Conclusion: Stent angioplasty in infrapopliteal arteries is a safe and effective technique for the treatment of patients with CLI. By consequent clinical monitoring high secondary patency rates can be achieved. The use of a bare metal stent seems to result in high limb salvage, primary and secondary patency rates in the mid-term follow-up.

  9. Performance analysis of the Single-Phase Grid-Connected Inverter of a photovoltaic system in water and wind applications

    Directory of Open Access Journals (Sweden)

    Borkowski Dariusz

    2016-01-01

    Full Text Available Single-phase grid connected inverters are nowadays broadly developed and tested in various types of applications especially in photovoltaic systems. The main aim of the inverter control strategy is to extract the maximum energy from the PV system which corresponds to the maximum power at certain conditions. However, the MPPT methods are also important in other renewable energy conversion systems. This paper analyses the performance of a commercially available photovoltaic inverter in water and wind systems. Presented models are implemented in a laboratory test bench in the form of torque characteristics realised by an induction motor fed by the inverter with vector control. The parameters are scaled into relative variables to provide a proper performance comparison. Presented tests include step response to assess the performance of a system dynamic. The dynamic tests showed a fast response of the investigated systems. The MPPT tracking accuracy tested under realistic profiles is similar for both cases: 98% and 96% respectively for the wind and water systems. These results prove the satisfactory performance of the MPPT of the PV microinverter in these applications.

  10. A New LCL -Filter With In-Series Parallel Resonant Circuit for Single-Phase Grid-Tied Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; Sun, Yunjie; Lin, Zhe

    2014-01-01

    When designing a higher order output power filter for a transformerless grid-tied converter using pulsewidth modulation (PWM), the requirements on the leakage current, the electromagnetic interference (EMI) noise, and the harmonics of the grid-injected current should be addressed. For an LCL-filt...

  11. A new PLL system using full order observer and PLL system modeling in a single phase grid-connected inverter

    DEFF Research Database (Denmark)

    Ko, Youngjong; Park, Kiwoo; Lee, Kyo-Beum

    2011-01-01

    In a grid connected power conversion system, the phase angle information of a grid voltage is very essential for supplying power to the grid since it is used for active and reactive power control. A Phase Locked Loop (PLL) system is used and should be robust because often the actual grid voltages...... are usually distorted by unexpected harmonics. However, conventional PLL systems have steady state errors when distorted voltages are used as a PLL input. Furthermore, using this distorted phase angle in the power control could reduce the output power quality. In this paper, the grid voltages are separated...... into fundamental and harmonic components and a virtual phase voltage is generated from the fundamental component using a Full Order Observer (FOO). Two virtual voltages are used as an input for the PLL system so the phase angle errors can be reduced and the output power quality can be improved. The dynamic...

  12. A New Design Method for the Passive Damped LCL and LLCL Filter-Based Single-Phase Grid-Tied Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; He, Yuanbin; Tang, Tianhao

    2013-01-01

    scheme with low power loss for the LLCL filter. Also, a simple engineering design criterion is proposed to find the optimized damping resistor value, which is both effective for the LCL filter and the LLCL filter. The control analysis and the power loss comparison for different filter cases are given....... All these are verified through the experiments on a 2-kW single-phase grid-tied inverter prototype using proportional resonant controllers. It is concluded that, compared with the LCL filter, the proposed passive damped LLCL filter can not only save the total filter inductance and reduce the volume...... control challenges. An active or a passive damping measure can be adopted to suppress the possible resonances between the grid and the inverter. For an application with a stiff grid, a passive damping method is often preferred for its simpleness and low cost. This paper introduces a new passive damping...

  13. 单相光伏并网全系统仿真研究%Single-Phase Photovoltaic Grid-Connected Whole System Simulation Study

    Institute of Scientific and Technical Information of China (English)

    吴威; 张文菁; 张吉; 陈昆; 裴召刚

    2012-01-01

      Introduction was made to two-stage topologic structure of single-phase photovoltaic grid-connected generation system. Analysis was made to double-closed loop control for feed-forward grid voltage control. The system realized DC busbar voltage sta-bility and unit power factor grid-connected current. The system model was built based on Matlab simulation platform. Simulation result shows that BOOST circuit has realized max power point tracking technology better, DC busbar voltage keeps stability and grid-connected current and grid voltage keep on same frequency and phase.%  介绍了光伏并网发电系统的两级式拓扑结构,分析了引入电网电压前馈的双闭环控制策略,实现直流母线电压稳定以及单位功率因数并网电流。基于 Matlab 仿真平台,搭建了系统模型。仿真结果表明,BOOST 电路较好地实现了最大功率点跟踪技术,直流母线电压保持稳定,并网电流与电网电压保持同频同相

  14. Efficacy and safety of dienogest in patients with endometriosis: A single-center observational study over 12 months.

    Science.gov (United States)

    Park, So Yun; Kim, Sung Hoon; Chae, Hee Dong; Kim, Chung-Hoon; Kang, Byung Moon

    2016-12-01

    To evaluate the efficacy and safety of dienogest treatment in patients who had received dienogest for 12 months or more to treat endometriosis. We analyzed the clinical data of 188 women with endometriosis who had been treated with 2 mg of dienogest once a day for 12 months or more at a single institute. We evaluated changes in endometriosis-associated pain and endometrioma size, recurrence rate, and adverse events following dienogest administration. Bone mineral density (BMD) was measured in patients who were prescribed dienogest for more than 18 months. Pain was significantly reduced at 12 months after dienogest medication. In those treated with dienogest due to recurrent endometrioma, the size of the endometrioma was significantly decreased at the 12-month and 18-month follow-ups. We found only one case of sonographic recurrence during dienogest administration among those who were treated postoperatively to prevent recurrence (1 of 114, 0.9%). The most common adverse drug reaction was uterine bleeding (3.2%), and other adverse events were generally tolerable and associated with low discontinuation rates (5.2%). Among the 50 patients in whom BMD was measured, 10 patients (20%) had a Z-score below the expected range for age. The administration of dienogest for a year or more seems to be highly effective in preventing recurrence after surgery, reducing endometriosis-associated pain, and decreasing the size of recurrent endometrioma, with a favorable safety and tolerability profile. However, BMD should be checked in patients on long-term medication due to possible bone loss in some women.

  15. 单相光伏并网逆变系统研究%Single-phase grid-connected photovoltaic inverter

    Institute of Scientific and Technical Information of China (English)

    郭克; 肖宁

    2012-01-01

    The current resources and conventional energy crisis caused by environmental pollution is an important global issues to be resolved. The solar photovoltaic power generation, as a new form of energy, gradually has a broad development prospect. The 3 kW single-phase power frequency isolated photovoltaic inverter was designed. The system simulation was performed with PSIM and Matlab softwares. The working principle and mathematical models of photovoltaic cell are discussed. The conformity of the output characteristics and mathematical models of the photovoltaic cell were verified. The function of the synchronism between the net current and grid voltage was validated.%现今资源能源的危机与传统能源发电所造成的环境污染成为全球的一个重要问题亟待解决,太阳能光伏发电作为新能源发电的一种形式,具有广阔的发展前景.本文设计了3 kW单相工频隔离型光伏并网逆变器.采用单相工频隔离型光伏并网逆变器为设计对象论述了光伏电池的工作原理和数学模型,应用PSIM软件、Matlab软件对系统进行仿真.验证了光伏电池输出特性与光伏等效电路及其数学模型的一致性,同时使并网电流与电网电压同频同相功能的实现得以验证.

  16. The effect of spacer grid critical component on pressure drop under both single and two phase flow conditions

    Energy Technology Data Exchange (ETDEWEB)

    Han, B.; Yang, B.W.; Zhang, H.; Mao, H.; Zha, Y. [Xi' an Jiaotong Univ., Shaanxi (China). Science and Technology Center for Advanced Nuclear Fuel Research

    2016-07-15

    As pressure drop is one of the most critical thermal hydraulic parameters for spacer grids the accurate estimation of it is the key to the design and development of spacer grids. Most of the available correlations for pressure drop do not contain any real geometrical parameters that characterize the grid effect. The main functions for spacer grid are structural support and flow mixing. Once the boundary sublayer near the rod bundle is disturbed, the liquid forms swirls or flow separation that affect pressure drop. However, under two phase flow conditions, due to the existence of steam bubble, the complexity for spacer grid are multiplied and pressure drop calculation becomes much more challenging. The influence of the dimple location, distance of mixing vane to the nearest strip, and the effect of inter-subchannel mixing among neighboring subchannels on pressure drop and downstream flow fields are analyzed in this paper. Based on this study, more detailed space grid geometry parameters are recommended for adding into the correlation when predicting pressure drop.

  17. Performance Improvement for Two-Stage Single-Phase Grid-Connected Converters Using a Fast DC Bus Control Scheme and a Novel Synchronous Frame Current Controller

    Directory of Open Access Journals (Sweden)

    Bingzhang Li

    2017-03-01

    Full Text Available Two-stage single-phase grid-connected converters are widely used in renewable energy applications. Due to the presence of a second harmonic ripple across the DC bus voltage, it is very challenging to design the DC bus voltage control scheme in single-phase grid-connected inverters. The DC bus voltage controller must filter the ripple and balance a tradeoff between low harmonic distortion and high bandwidth. This paper presents a fast DC bus voltage controller, which uses a second order digital finite impulse response (FIR notch filter in conjunction with input power feedforward scheme to ensure the steady-state and dynamic performance. To gain the input power without extra hardware, a Kalman filter is incorporated to estimate the DC bus input current. At the same time, a modulation compensation strategy is implemented to eliminate the nonlinearity of the grid current control loop, which is caused by the DC bus voltage ripple. Moreover, a novel synchronous frame current controller for single-phase systems is also introduced, and its equivalent model in stationary frame has been derived. Simulation and experimental results are provided to verify the effective of the proposed control scheme.

  18. 小功率单相光伏并网逆变器的研究%Research onsmall power single-phase grid-connected inverters

    Institute of Scientific and Technical Information of China (English)

    柯程虎; 张辉

    2014-01-01

    主要针对双级单相并网逆变系统中DC/AC环节所用的锁相环与电流环控制算法进行研究,提出一种小功率单相光伏并网逆变器的设计方案。根据瞬时无功理论的单相锁相环技术,使用二阶广义积分器构造正交信号,改善了目前锁相环技术存在锁相误差及滤波延时的不足,提高了系统的精准度和稳定性。电流环控制采用比例谐振算法,消除了稳态误差,有效减小并网电流的总谐波失真,满足并网要求。结果验证了该方案的合理性和有效性。%A low-power single-phase grid-connected photovoltaic inverter is presented for the phase-locked loop (PLL) and current loop control algorithm in DC/AC of the two-stage single-phase grid-connected inverter system. The single-phase PLL technology based on instantaneous reactive power theory and second-order generalized integrator constructing orthogonal signal are used to decline the phase-locked error and filter delay, which enhances the accuracy and stability of the PLL circuit. Proportion resonance algorithm is introduced in current loop control to eliminate the steady-state error so that the Total Harmonic Distortion (THD) of the grid current can meet the grid-connected requirement. The experimental results indicate the rationality and validity of the solution.

  19. 电网谐波背景下单相并网逆变器的锁相方法%Phase-locked Loop for Single Phase Grid-connected Inverters in a Harmonic Distorted Grid

    Institute of Scientific and Technical Information of China (English)

    王鹿军; 张冲; 吕征宇

    2013-01-01

    Based on the fact that the grid voltage of distribution network with distributed generators connected usually contains low order harmonics caused by adjacent nonlinear loads,a phase-locked loop (PLL) structure is proposed for single phase gridconnected inverters.The proposed method has a coupling feedback structure composed of a main module and multi notch filters,in which the main module aims to estimate fundamental component and multi notch filters aim to get harmonic components.The main module is an amplitude-frequency-phase-locked loop (AFPLL) using gradient descent method.The harmonic modules are simple second order notch filters (NFs).The complex structure can eliminate steady state errors in dealing with harmonic distorted grid voltage.Finally,the proposed PLL is verified by harmonic distorted grid voltage synchronization experiment,phase mutation experiment,amplitude mutation experiment and frequency mutation experiment.The experimental results show that the proposed PLL not only can eliminate steady state error in harmonic distorted grid voltage,but also has a quick response when grid voltage suddenly changes.%针对分布式电源接入的配电网因临近非线性负载而含有大量低次谐波的问题,提出了一种适用于单相并网逆变器的锁相方法.该方法的核心是一个由主模块和多个谐波模块组成的交错耦合反馈结构,其中主模块是依据梯度下降法来估测基波幅值频率的锁相环(AFPLL),谐波模块是简单的二阶陷波滤波器(NF).该复合结构可有效消除传统锁相方法在处理畸变电压信号时存在的稳态误差.分别通过畸变电压锁相实验、相位突变实验、幅值突变实验和频率突变实验,评估了该锁相方法的稳态和动态性能.实验结果表明,所提出的锁相方法不但在电压信号严重畸变时具有较高的锁相精度,而且在电压信号发生突变时也具有较快的响应速度.

  20. Leakage current analysis of a single-phase transformer-less PV inverter connected to the grid

    DEFF Research Database (Denmark)

    Ma, Lin; Tang, F.; Zhou, F.;

    2009-01-01

    Due to the large surface of the PV generator, its stray capacity with respect to the ground reaches values that can be quite high. When no transformer is used in a grid-connected PV system, common-mode current, which caused by the common mode voltage, can flow through the stray capacitance betwee...

  1. A Single-Phase Transformerless Inverter With Charge Pump Circuit Concept for Grid-Tied PV Applications

    DEFF Research Database (Denmark)

    Ardashir, Jaber Fallah; Sabahi, Mehran; Hosseini, Seyed Hossein

    2017-01-01

    resonant control strategy is used to control the injected current. The main benefits of the proposed inverter are: the neutral of the grid is directly connected to the negative terminal of the PV panel, so the leakage current is eliminated; its compact size; low cost; the used dc voltage of the proposed...

  2. Single star progenitors of long gamma-ray bursts I. Model grids and redshift dependent GRB rate

    NARCIS (Netherlands)

    Yoon, S.C.; Langer, N.; Norman, C.

    2006-01-01

    We present grids of massive star evolution models at four different metallicities (Z=0.004, 0.002, 0.001, 0.00001). The effects of rotation on the stellar structure and the transport of angular momentum and chemical elements through the Spruit-Tayler dynamo and rotationally induced instabilities are

  3. Single star progenitors of long gamma-ray bursts.I. Model grids and redshift dependent GRB rate

    NARCIS (Netherlands)

    Yoon, S.C.; Langer, N.; Norman, C.

    2006-01-01

    We present grids of massive star evolution models at four different metallicities (Z = 0.004, 0.002, 0.001, 0.00001). The effects of rotation on the stellar structure and the transport of angular momentum and chemical elements through the Spruit-Tayler dynamo and rotationally induced instabilities a

  4. Control and dynamic analysis of a parallel-connected single active bridge DC-DC converter for DC-grid wind farm application

    DEFF Research Database (Denmark)

    Park, Kiwoo; Chen, Zhe

    2015-01-01

    This study presents a control strategy and its dynamic analysis of a high-power dc-dc converter, which is constructed with the parallel-connected single active bridge (SAB) dc-dc converters for dc-grid wind farm applications. The structural and operational characteristics of the SAB dc-dc converter...... have several advantages for high-power applications, and the modular concept of the parallel-connected converter is highly beneficial especially for offshore wind farm applications in terms of maintenance cost and fault tolerance. To justify the feasibility of the parallel-connected SAB dc-dc converter...... for dc-grid wind farm applications, an input voltage control method based on the PI control will be introduced and the dynamics of the overall system will be analysed. The analysis results are to be verified by means of simulations and experiments....

  5. Blotting-free and lossless cryo-electron microscopy grid preparation from nanoliter-sized protein samples and single-cell extracts.

    Science.gov (United States)

    Arnold, Stefan A; Albiez, Stefan; Bieri, Andrej; Syntychaki, Anastasia; Adaixo, Ricardo; McLeod, Robert A; Goldie, Kenneth N; Stahlberg, Henning; Braun, Thomas

    2017-03-01

    We present a sample preparation method for cryo-electron microscopy (cryo-EM) that requires only 3-20nL of sample to prepare a cryo-EM grid, depending on the protocol used. The sample is applied and spread on the grid by a microcapillary. The procedure does not involve any blotting steps, and real-time monitoring allows the water film thickness to be assessed and decreased to an optimum value prior to vitrification. We demonstrate that the method is suitable for high-resolution cryo-EM and will enable alternative electron microscopy approaches, such as single-cell visual proteomics. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  6. One month in the life of a neuron: longitudinal single-unit electrophysiology in the monkey visual system.

    Science.gov (United States)

    McMahon, David B T; Bondar, Igor V; Afuwape, Olusoji A T; Ide, David C; Leopold, David A

    2014-10-01

    Conventional recording methods generally preclude following the activity of the same neurons in awake animals across days. This limits our ability to systematically investigate the principles of neuronal specialization, or to study phenomena that evolve over multiple days such as experience-dependent plasticity. To redress this shortcoming, we developed a drivable, chronically implanted microwire recording preparation that allowed us to follow visual responses in inferotemporal (IT) cortex in awake behaving monkeys across multiple days, and in many cases across months. The microwire bundle and other implanted components were MRI compatible and thus permitted in the same animals both functional imaging and long-term recording from multiple neurons in deep structures within a region the approximate size of one voxel (image libraries presented over the course of days. We demonstrate this possibility by screening the visual responses of single neurons to a set of 10,000 stimuli.

  7. Changing from computing grid to knowledge grid in life-science grid.

    Science.gov (United States)

    Talukdar, Veera; Konar, Amit; Datta, Ayan; Choudhury, Anamika Roy

    2009-09-01

    Grid computing has a great potential to become a standard cyber infrastructure for life sciences that often require high-performance computing and large data handling, which exceeds the computing capacity of a single institution. Grid computer applies the resources of many computers in a network to a single problem at the same time. It is useful to scientific problems that require a great number of computer processing cycles or access to a large amount of data.As biologists,we are constantly discovering millions of genes and genome features, which are assembled in a library and distributed on computers around the world.This means that new, innovative methods must be developed that exploit the re-sources available for extensive calculations - for example grid computing.This survey reviews the latest grid technologies from the viewpoints of computing grid, data grid and knowledge grid. Computing grid technologies have been matured enough to solve high-throughput real-world life scientific problems. Data grid technologies are strong candidates for realizing a "resourceome" for bioinformatics. Knowledge grids should be designed not only from sharing explicit knowledge on computers but also from community formulation for sharing tacit knowledge among a community. By extending the concept of grid from computing grid to knowledge grid, it is possible to make use of a grid as not only sharable computing resources, but also as time and place in which people work together, create knowledge, and share knowledge and experiences in a community.

  8. Balance in single-limb stance after surgically treated ankle fractures: a 14-month follow-up

    Directory of Open Access Journals (Sweden)

    Ageberg Eva

    2006-04-01

    Full Text Available Abstract Background The maintenance of postural control is fundamental for different types of physical activity. This can be measured by having subjects stand on one leg on a force plate. Many studies assessing standing balance have previously been carried out in patients with ankle ligament injuries but not in patients with ankle fractures. The aim of this study was to evaluate whether patients operated on because of an ankle fracture had impaired postural control compared to an uninjured age- and gender-matched control group. Methods Fifty-four individuals (patients operated on because of an ankle fracture were examined 14 months postoperatively. Muscle strength, ankle mobility, and single-limb stance on a force-platform were measured. Average speed of centre of pressure movements and number of movements exceeding 10 mm from the mean value of centre of pressure were registered in the frontal and sagittal planes on a force-platform. Fifty-four age- and gender-matched uninjured individuals (controls were examined in the single-limb stance test only. The paired Student t-test was used for comparisons between patients' injured and uninjured legs and between side-matched legs within the controls. The independent Student t-test was used for comparisons between patients and controls. The Chi-square test, and when applicable, Fisher's exact test were used for comparisons between groups. Multiple logistic regression was performed to identify factors associated with belonging to the group unable to complete the single-limb stance test on the force-platform. Results Fourteen of the 54 patients (26% did not manage to complete the single-limb stance test on the force-platform, whereas all controls managed this (p Conclusion One in four patients operated on because of an ankle fracture had impaired postural control compared to an age- and gender-matched control group. Age over 45 years and decreased strength in the ankle plantar flexors and dorsiflexors

  9. Grid Computing

    Indian Academy of Sciences (India)

    2016-05-01

    A computing grid interconnects resources such as high performancecomputers, scientific databases, and computercontrolledscientific instruments of cooperating organizationseach of which is autonomous. It precedes and is quitedifferent from cloud computing, which provides computingresources by vendors to customers on demand. In this article,we describe the grid computing model and enumerate themajor differences between grid and cloud computing.

  10. Analysis and Comparison of Voltage Dependent Charging Strategies for Single-Phase Electric Vehicles in an Unbalanced Danish Distribution Grid

    DEFF Research Database (Denmark)

    Álvarez, Jorge Nájera; Knezovic, Katarina; Marinelli, Mattia

    2016-01-01

    This paper studies four voltage dependent solutions for modulating the charging of multiple Electric Vehicles (EVs) in a real Danish network. Uncontrolled EV charging, especially in grid with high EV penetration, can result in overloaded lines and transformers, low-voltages and other performance......-in on phases with lower voltages are constrained during the charging period. In order to solve instability issues which may occur due to lack of communication between the controllers, several improvements are applied to the aforementioned droop control. Simulation results demonstrate the performance...

  11. 实用单相并网逆变器的设计%Design of a Practical Single-phase Grid Connected Inverter

    Institute of Scientific and Technical Information of China (English)

    郝敏啟; 贾传圣

    2014-01-01

    光伏发电系统的核心是并网逆变器,根据单相光伏并网逆变器的基本原理和控制策略,设计的单相并网逆变器采用前级DC/DC高频升压,后级DC/AC工频逆变的前后两级结构,这样的设计模式具有电路简单、性能稳定、转换效率高等优点。给出了硬件主回路,DC/DC控制模块选用的是SG3525控制芯片,DC/AC控制模块选用TI公司的DSP芯片TMS320F240作为控制CPU,通过其精确控制使整个逆变器可靠、稳定的工作。%The core of a photovoltaic power system is the grid connected inverter.On the basic principle and control strategy of the single-phase photovoltaic grid connected inverter,this paper designs a single-phase grid connected inverter,using a DC/DC high-frequency voltage rise at the first stage and a DC/AC power frequency conversion at the second stage.This design mode has advantages such as simple circuit,stable performance,and high conversion efficiency.The main circuit of the hardware is given.The DC/DC control module uses SG3525 control chip,DC/AC control module uses TI Company's DSP chip TMS320F240 as control CPU.Through precise control,the whole converter can work steadily and reliably.

  12. Experience in Developing a Single-Phase Two Winding 5 kW Self-excited Induction Generator for Off-Grid Renewable Energy Based Power Generation

    Science.gov (United States)

    Murthy, S. S.; Singh, Bhim; Sandeep, Vuddanti

    2016-06-01

    This paper deals with the design and development of a novel single-phase two winding self-excited squirrel cage induction generator (SEIG) for off-grid renewable energy based power generation. The principles underlying the design process and experience with SPEED design tool are described to design a 5 kW, 50 Hz, 230 V, 4 pole single phase AC generator. All possible configurations to reduce harmonic components of induced e.m.f. are attempted for desired performance and to get an optimum design keeping in view the manufacturing constraints. The development of a prototype based on this design has been completed with the help of an industry. Typical test results on the prototype are presented to demonstrate its performance. Computed results are obtained with a design based computational procedure for performance analysis and a critical comparison is made with test results.

  13. Algebraic grid generation for complex geometries

    Science.gov (United States)

    Shih, T. I.-P.; Bailey, R. T.; Nguyen, H. L.; Roelke, R. J.

    1991-01-01

    An efficient computer program called GRID2D/3D has been developed to generate single and composite grid systems within geometrically complex two- and three-dimensional (2D and 3D) spatial domains that can deform with time. GRID2D/3D generates single grid systems by using algebraic grid generation methods based on transfinite interpolation. The distribution of grid points within the spatial domain is controlled by stretching functions and grid lines can intersect boundaries of the spatial domain orthogonally. GRID2D/3D generates composite grid systems by patching together two or more single grid systems. The patching can be discontinuous or continuous. For 2D spatial domains the boundary curves are constructed by using either cubic or tension spline interpolation. For 3D spatial domains the boundary surfaces are constructed by using a new technique, developed in this study, referred to as 3D bidirectional Hermite interpolation.

  14. Grid Frequency Support by Single-Phase Electric Vehicles: Fast Primary Control Enhanced by a Stabilizer Algorithm

    DEFF Research Database (Denmark)

    Zecchino, Antonio; Rezkalla, Michel M.N.; Marinelli, Mattia

    2016-01-01

    ancillary services for supporting the power grid. This paper presents modeling and analysis of the benefits of primary frequency regulation by electric vehicles in a microgrid. An innovative control logic algorithm is introduced, with the purpose of curtailing the number of current set-point variations...... that the battery needs to perform during the regulation process. It is shown that, compared to traditional droop-control approaches, the proposed solution assures same effects in terms of frequency containment, by employing a considerably lower number of variations of battery current set-point. The modeled low......Electric vehicles are growing in popularity as a zero emission and efficient mode of transport against traditional internal combustion engine-based vehicles. Considerable as flexible distributed energy storage systems, by adjusting the battery charging process they can potentially provide different...

  15. A Systematic Method for Designing a PR Controller and Active Damping of the LCL Filter for Single-Phase Grid-Connected PV Inverters

    Directory of Open Access Journals (Sweden)

    Ningyun Zhang

    2014-06-01

    Full Text Available The Proportional Resonant (PR current controller provides gains at a certain frequency (resonant frequency and eliminates steady state errors. Therefore, the PR controller can be successfully applied to single grid-connected PV inverter current control. On the contrary, a PI controller has steady-state errors and limited disturbance rejection capability. Compared with the L- and LC filters, the LCL filter has excellent harmonic suppression capability, but the inherent resonant peak of the LCL filter may introduce instability in the whole system. Therefore, damping must be introduced to improve the control of the system. Considering the controller and the LCL filter active damping as a whole system makes the controller design method more complex. In fact, their frequency responses may affect each other. The traditional trial-and-error procedure is too time-consuming and the design process is inefficient. This paper provides a detailed analysis of the frequency response influence between the PR controller and the LCL filter regarded as a whole system. In addition, the paper presents a systematic method for designing controller parameters and the capacitor current feedback coefficient factor of LCL filter active-damping. The new method relies on meeting the stable margins of the system. Moreover, the paper also clarifies the impact of the grid on the inverter output current. Numerical simulation and a 3 kW laboratory setup assessed the feasibility and effectiveness of the proposed method.

  16. Fibonacci Grids

    Science.gov (United States)

    Swinbank, Richard; Purser, James

    2006-01-01

    Recent years have seen a resurgence of interest in a variety of non-standard computational grids for global numerical prediction. The motivation has been to reduce problems associated with the converging meridians and the polar singularities of conventional regular latitude-longitude grids. A further impetus has come from the adoption of massively parallel computers, for which it is necessary to distribute work equitably across the processors; this is more practicable for some non-standard grids. Desirable attributes of a grid for high-order spatial finite differencing are: (i) geometrical regularity; (ii) a homogeneous and approximately isotropic spatial resolution; (iii) a low proportion of the grid points where the numerical procedures require special customization (such as near coordinate singularities or grid edges). One family of grid arrangements which, to our knowledge, has never before been applied to numerical weather prediction, but which appears to offer several technical advantages, are what we shall refer to as "Fibonacci grids". They can be thought of as mathematically ideal generalizations of the patterns occurring naturally in the spiral arrangements of seeds and fruit found in sunflower heads and pineapples (to give two of the many botanical examples). These grids possess virtually uniform and highly isotropic resolution, with an equal area for each grid point. There are only two compact singular regions on a sphere that require customized numerics. We demonstrate the practicality of these grids in shallow water simulations, and discuss the prospects for efficiently using these frameworks in three-dimensional semi-implicit and semi-Lagrangian weather prediction or climate models.

  17. Single star progenitors of long gamma-ray bursts I: Model grids and redshift dependent GRB rate

    CERN Document Server

    Yoon, S C; Norman, C

    2006-01-01

    We present grids of massive star evolution models at four different metallicities (Z=0.004, 0.002, 0.001, 0.00001). The effects of rotation on the stellar structure and the transport of angular momentum and chemical elements through the Spruit-Tayler dynamo and rotationally induced instabilities are considered. After discussing uncertainties involved with the adopted physics, we elaborate the final fate of massive stars as a function of initial mass and spin rate, at each considered metallicity. In particular, we investigate for which initial conditions long gamma-ray bursts (GRBs) are expected to be produced in the frame of the collapsar model. Then, using an empirical spin distribution of young massive metal-poor stars and a specified metallicity-dependent history of star-formation, we compute the expected GRB rate as function of metallicity and redshift based on our stellar evolution models. The GRB production in our models is limited to metallicities of Z \\lsim 0.004, with the consequence that about 50 % ...

  18. Lead grids

    CERN Multimedia

    1974-01-01

    One of the 150 lead grids used in the multiwire proportional chamber g-ray detector. The 0.75 mm diameter holes are spaced 1 mm centre to centre. The grids were made by chemical cutting techniques in the Godet Workshop of the SB Physics.

  19. A Cost-Effective Power Ramp-Rate Control Strategy for Single-Phase Two-Stage Grid-Connected Photovoltaic Systems

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Blaabjerg, Frede

    2016-01-01

    In the case of a wide-scale adoption of grid-connected Photovoltaic (PV) systems, more fluctuated power will be injected into the grid due to the intermittency of solar PV energy. A sudden change in the PV power can potentially induce grid voltage fluctuations, and thus challenge the stability...

  20. Spatiotemporal factors affecting fish harvest and their use in estimating the monthly yield of single otter trawls in Putuo district of Zhoushan, China

    Institute of Scientific and Technical Information of China (English)

    WANG Yingbin; ZHENG Ji; WANG Yang; ZHENG Xianzhi

    2012-01-01

    We used generalized additive models (GAM) to analyze the relationship between spatiotemporal factors and catch,and to estimate the monthly marine fishery yield of single otter trawls in Putuo district of Zhoushan,China.We used logbooks from five commercial fishing boats and data in government's monthly statistical reports.We developed two GAM models:one included temporal variables (month and hauling time) and spatial variables (longitude and latitude),and another included just two variables,month and the number of fishing boats.Our results suggest that temporal factors explained more of the variability in catch than spatial factors.Furthermore,month explained the majority of variation in catch.Change in spatial distribution of fleet had a temporal component as the boats fished within a relatively small area within the same month,but the area varied among months.The number of boats fishing in each month also explained a large proportion of the variation in catch.Engine power had no effect on catch.The pseudo-coefficients (PCf) of the two GAMs were 0.13 and 0.29 respectively,indicating the both had good fits.The model yielded estimates that were very similar to those in the governmental reports between January to September,with relative estimate errors (REE) of <18%.However,the yields in October and November were significantly underestimated,with REEs of 36% and 27%,respectively.

  1. Grid Security

    CERN Document Server

    CERN. Geneva

    2004-01-01

    The aim of Grid computing is to enable the easy and open sharing of resources between large and highly distributed communities of scientists and institutes across many independent administrative domains. Convincing site security officers and computer centre managers to allow this to happen in view of today's ever-increasing Internet security problems is a major challenge. Convincing users and application developers to take security seriously is equally difficult. This paper will describe the main Grid security issues, both in terms of technology and policy, that have been tackled over recent years in LCG and related Grid projects. Achievements to date will be described and opportunities for future improvements will be addressed.

  2. Single-phase sine wave active inverter grid power supply%单相正弦波有源逆变并网电源

    Institute of Scientific and Technical Information of China (English)

    陈继栋; 施崇阳; 周乐意

    2011-01-01

    Based on the purpose of efficient use of energy, a power system is designed. This system uses P87C52X2BN and FPGA chip EP1C6Q240C8N completing active inverter single-phase sine wave loading operation and safety grid with 220V utility output power. The system includes single-phase inverter, data acquisition and grid conditions detection.Single-phase inverter is the core. This system adopts full bridge inverter, completing DC-AC efficient conversion. Final full load output power measures 72W,efficiency is higher than 85%.The stability of output voltage is high and the waveform distortion is small.The whole system is safe and stable with simple operation and certain use value.%基于有效利用能源的目的,设计了一个电源系统。采用单片机P87C52X2BN和FPGA芯片EP1C6Q240C8N相结合的方法,配合外围电路,实现单相正弦波有源逆变器带负载运行和与220 V市电安全并网。系统主要由单相全桥逆变、数据采集、并网条件检测等几部分组成,其中单相逆变是核心,系统采用全桥逆变,完成DC-AC高效率转换。最终测得满载输出功率为72 W,效率高于85%,输出电压稳定度高,波形失真度小。整个系统安全可靠、稳定性能好、操作简单,具有一定的使用价值。

  3. Grid oscillators

    Science.gov (United States)

    Popovic, Zorana B.; Kim, Moonil; Rutledge, David B.

    1988-01-01

    Loading a two-dimensional grid with active devices offers a means of combining the power of solid-state oscillators in the microwave and millimeter-wave range. The grid structure allows a large number of negative resistance devices to be combined. This approach is attractive because the active devices do not require an external locking signal, and the combining is done in free space. In addition, the loaded grid is a planar structure amenable to monolithic integration. Measurements on a 25-MESFET grid at 9.7 GHz show power-combining and frequency-locking without an external locking signal, with an ERP of 37 W. Experimental far-field patterns agree with theoretical results obtained using reciprocity.

  4. Which angiographic variable best describes functional status 6 months after successful single-vessel coronary balloon angiopasty?

    NARCIS (Netherlands)

    B.J.W.M. Rensing (Benno); W.R.M. Hermans (Walter); P.J. de Feyter (Pim); P.W.J.C. Serruys (Patrick); J.W. Deckers (Jaap)

    1993-01-01

    textabstractOBJECTIVES. The aim of this study was to determine which quantitative angiographic variable best describes functional status 6 months after coronary balloon angioplasty. BACKGROUND. Several angiographic restenosis criteria have been developed. These can be divided into those that describ

  5. Grid Computing

    Science.gov (United States)

    Foster, Ian

    2001-08-01

    The term "Grid Computing" refers to the use, for computational purposes, of emerging distributed Grid infrastructures: that is, network and middleware services designed to provide on-demand and high-performance access to all important computational resources within an organization or community. Grid computing promises to enable both evolutionary and revolutionary changes in the practice of computational science and engineering based on new application modalities such as high-speed distributed analysis of large datasets, collaborative engineering and visualization, desktop access to computation via "science portals," rapid parameter studies and Monte Carlo simulations that use all available resources within an organization, and online analysis of data from scientific instruments. In this article, I examine the status of Grid computing circa 2000, briefly reviewing some relevant history, outlining major current Grid research and development activities, and pointing out likely directions for future work. I also present a number of case studies, selected to illustrate the potential of Grid computing in various areas of science.

  6. 考虑电网电压基波锁相环控制的单级式光伏逆变器柔性并网方法%Flexible Grid-Connection Method for Single-Stage Photovoltaic Inverter Based on Phase-Locked Loop Control for Grid Fundamental Frequency Voltage

    Institute of Scientific and Technical Information of China (English)

    邢浩江; 张东来; 李铁才; 王子才

    2012-01-01

    针对目前光伏并网逆变器存在基波电压定向偏差、直流电压崩溃以及逆变器并网对电网产生冲击的问题,提出一种基于电网电压基波锁相环技术的三环控制方法,应用于单级式光伏并网逆变器,提高逆变器输出性能,并实现柔性并网.该方法首先基于电网电压基波的锁相环技术,实现对电网电压基波分量定向,定向效果取决于锁相环的设计性能;其次采用三环控制结构避免直流电压崩溃问题,减小输出电流总谐波因数;最后采用合理的并网控制逻辑,实现光伏逆变器柔性并网.实验验证了该方法的可行性,可提高系统动态响应实时性与稳态跟踪精度,实现系统高可靠运行.%In allusion to orientation deviation of grid fundamental frequency voltage and DC voltage collapse of existing grid-connecting photovoltaic (PV) inverter and the impact to power grid due to grid-connection of photovoltaic inverter, a three-loop control method based on phase-locked loop (PLL) control for grid fundamental frequency voltage was proposed and applied to single-stage grid-connecting PV inverter to improve output performance of the inverter and implement flexible grid-connection. Firstly, based on PLL control for grid fundamental frequency voltage, the orientation of grid fundamental frequency voltage was performed and the effect of the orientation was dependent on the designed performance of the PLL; secondly, the three loop-control structure was adopted to avoid DC voltage collapse and decrease total harmonic factor of output current; finally reasonable grid-connecting control logic was adopted to implement flexible grid-connection of PV inverter. The feasibility of the proposed method was verified by experiments, and experiment results showed that using the proposed method both real-time performance of dynamic response and steady state tracking accuracy could be improved.

  7. ACDF Using the Solis Cage with Iliac Bone Graft in Single Level: Clinical and Radiological Outcomes in Average 36 months Follow-up.

    Science.gov (United States)

    Oh, Si-Hyuck; Yoon, Kyeong-Wook; Kim, Young-Jin; Lee, Sang-Koo

    2013-06-01

    To evaluate the utility of anterior cervical discectomy and fusion (ACDF) with polyetheretherketone (PEEK) cage and autograft through long term(average 36 months) follow-up. Thirty selected patients (male:20/female:10) who suffered from cervical radiculopathy, myelopathy or radiculomyelopathy underwent a single level ACDF with PEEK cage and autograft from iliac crest from March 2006 to July 2008 in single institute. We followed patients for an average 36.4±8.1 months (ranged from 23 to 49 months). The Japanese Orthopedic Association (JOA) score for evaluation of myelopathy and visual analogue scale (VAS) for radiating pain was used to estimate postoperative clinical outcome. Plain x-ray on true lateral standing flexion, extension and neutral position view and 3D CT scan were used every 6 months after surgery during follow-up period. The mean VAS and JOA scoring improved significantly after the surgery and radiological fusion rate was accomplished by 100% 36 months after the surgery. We had no complication related with the surgery except one case of osteomyelitis. There was one case of Grade I fusion, four cases of grade II, and 25 cases of grade III by radiologic evaluation. This long term follow-up study for ACDF with PEEK cage shows that this surgical method is comparable with other anterior cervical fusion methods in terms of clinical outcomes and radiologic fusion rate.

  8. Results from a 12 months, randomized, clinical trial comparing an olmesartan/amlodipine single pill combination to olmesartan and amlodipine monotherapies on blood pressure and inflammation.

    Science.gov (United States)

    Derosa, Giuseppe; Cicero, Arrigo F G; Carbone, Anna; Querci, Fabrizio; Fogari, Elena; D'Angelo, Angela; Maffioli, Pamela

    2014-01-23

    Hypertension affects nearly 1 in 3 adults in the United States, and it is an important modifiable risk factor for coronary artery disease, heart failure, renal failure, and stroke. The aim of this study was to evaluate the effects of a fixed-dose olmesartan/amlodipine combination on blood pressure control, lipid profile, insulin sensitivity, and inflammation compared to singles monotherapies. We randomized 276 hypertensive patients to olmesartan 20 mg, amlodipine 10mg or a single pill containing a fixed-dose olmesartan/amlodipine combination 20/5mg for 12 months. We evaluated: body weight, body mass index (BMI), systolic and diastolic blood pressure (SBP and DBP), fasting plasma glucose (FPG), fasting plasma insulin (FPI), lipid profile, omentin, chemerin, high sensitivity C-reactive protein (Hs-CRP). At baseline, and after 6 and 12 months, patients underwent an euglycemic, hyperinsulinemic clamp to assess insulin sensitivity (M value). Olmesartan/amlodipine combination was more effective than amlodipine or olmesartan in reducing blood pressure. Olmesartan/amlodipine combination, but not amlodipine, decreased FPG after 12 months. Olmesartan/amlodipine combination better decreased FPI and HOMA index and increased M value compared to olmesartan and amlodipine monotherapies. Olmesartan/amlodipine significantly decreased chemerin and omentin compared to olmesartan and amlodipine. Other than to be more effective in reducing blood pressure, olmesartan/amlodipine single pill combination gave also a major increase of insulin sensitivity and a decrease of inflammatory markers compared to single monotherapies. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Single-Phase LLCL-Filter-based Grid-Tied Inverter with Low-Pass Filter Based Capacitor Current Feedback Active damper

    DEFF Research Database (Denmark)

    Liu, Yuan; Wu, Weimin; Li, Yun

    2016-01-01

    The capacitor-current-feedback active damping method is attractive for high-order-filter-based high power grid-tied inverter when the grid impedance varies within a wide range. In order to improve the system control bandwidth and attenuate the high order grid background harmonics by using the quasi....... In this paper, a low pass filter is proposed to be inserted in the capacitor current feedback loop op LLCL-filter based grid-tied inverter together with a digital proportional and differential compensator. The detailed theoretical analysis is given. For verification, simulations on a 2kW/220V/10kHz LLCL...

  10. Supramolecular control over molecular magnetic materials: γ-cyclodextrin-templated grid of cobalt(II) single-ion magnets.

    Science.gov (United States)

    Nedelko, Natalia; Kornowicz, Arkadiusz; Justyniak, Iwona; Aleshkevych, Pavlo; Prochowicz, Daniel; Krupiński, Piotr; Dorosh, Orest; Ślawska-Waniewska, Anna; Lewiński, Janusz

    2014-12-15

    Single-ion magnets (SIMs) are potential building blocks of novel quantum computing devices. Unique magnetic properties of SIMs require effective separation of magnetic ions and can be tuned by even slight changes in their coordination sphere geometry. We show that an additional level of tailorability in the design of SIMs can be achieved by organizing magnetic ions into supramolecular architectures, resulting in gaining control over magnetic ion packing. Here, γ-cyclodextrin was used to template magnetic Co(II) and nonmagnetic auxiliary Li(+) ions to form a heterometallic {Co, Li, Li}4 ring. In the sandwich-type complex [(γ-CD)2Co4Li8(H2O)12] spatially separated Co(II) ions are prevented from superexchange magnetic coupling. Ac/dc magnetic and EPR studies demonstrated that individual Co(II) ions with positive zero-field splitting exhibit field-induced slow magnetic relaxation consistent with the SIMs' behavior, which is exceptional in complexes with easy-plane magnetic anisotropy.

  11. Control Strategy of Single-Phase Single-Stage LCL Grid-Connected Photovoltaic Inverter System%单相单级光伏LCL并网逆变系统控制策略

    Institute of Scientific and Technical Information of China (English)

    江渝; 姜琦; 黄敏; 梁波

    2015-01-01

    In order to control the grid current completely, the DC voltage of the inverter meets the voltage requirement for the traditional LCL grid-connected inverter system. And the required voltage increases with the grid voltage increasing. The lower output voltage for each cell results in the fact that in the traditional single-stage PV system cells are often in series-connection for meeting the DC voltage requirement, which is disadvantage for the further application of PV system. In this paper, a new LCL grid-connected PV inverter system and its corresponding control strategy is proposed. The proposed LCL inverter is able to control the gird current effectively and abandon DC voltage requirement. Furthermore, the gird voltage has no influence on the control of proposed inverter. The proposed LCL has a strong high-frequency attenuation capability just like the traditional LCL circuit. In addition, a method is introduced to suppress the resonance and improve the stability of system, which extracts the fundamental component of grid current. And the real maximum power point of PV cell is judged according to the DC component and second harmonic of the PV voltage and current. The maximum power tracking of PV is achieved by controlling the grid current. Then the proposed system with the corresponding control strategy is verified by the simulation.%在传统的光伏LCL并网逆变系统中,直流侧电压只有大于其最小需求电压时,逆变器才能有效控制并网电流,而最小需求电压随电网电压的增加而增加。为此需在单级逆变系统中串联多块光伏电池以提高其直流侧电压,但这提高了光伏并网发电系统的应用门槛。对此提出一种新型的LCL并网逆变系统及其控制方法,该逆变系统对并网电流有较强的控制能力,对逆变器直流侧电压没有要求,且电网电压对其控制能力也没有影响。与传统LCL电路相比,新型LCL电路同样具有较好的滤波效果

  12. The Grid2003 Production Grid Principles and Practice

    CERN Document Server

    Foster, I; Gose, S; Maltsev, N; May, E; Rodríguez, A; Sulakhe, D; Vaniachine, A; Shank, J; Youssef, S; Adams, D; Baker, R; Deng, W; Smith, J; Yu, D; Legrand, I; Singh, S; Steenberg, C; Xia, Y; Afaq, A; Berman, E; Annis, J; Bauerdick, L A T; Ernst, M; Fisk, I; Giacchetti, L; Graham, G; Heavey, A; Kaiser, J; Kuropatkin, N; Pordes, R; Sekhri, V; Weigand, J; Wu, Y; Baker, K; Sorrillo, L; Huth, J; Allen, M; Grundhoefer, L; Hicks, J; Luehring, F C; Peck, S; Quick, R; Simms, S; Fekete, G; Van den Berg, J; Cho, K; Kwon, K; Son, D; Park, H; Canon, S; Jackson, K; Konerding, D E; Lee, J; Olson, D; Sakrejda, I; Tierney, B; Green, M; Miller, R; Letts, J; Martin, T; Bury, D; Dumitrescu, C; Engh, D; Gardner, R; Mambelli, M; Smirnov, Y; Voeckler, J; Wilde, M; Zhao, Y; Zhao, X; Avery, P; Cavanaugh, R J; Kim, B; Prescott, C; Rodríguez, J; Zahn, A; McKee, S; Jordan, C; Prewett, J; Thomas, T; Severini, H; Clifford, B; Deelman, E; Flon, L; Kesselman, C; Mehta, G; Olomu, N; Vahi, K; De, K; McGuigan, P; Sosebee, M; Bradley, D; Couvares, P; De Smet, A; Kireyev, C; Paulson, E; Roy, A; Koranda, S; Moe, B; Brown, B; Sheldon, P

    2004-01-01

    The Grid2003 Project has deployed a multi-virtual organization, application-driven grid laboratory ("GridS") that has sustained for several months the production-level services required by physics experiments of the Large Hadron Collider at CERN (ATLAS and CMS), the Sloan Digital Sky Survey project, the gravitational wave search experiment LIGO, the BTeV experiment at Fermilab, as well as applications in molecular structure analysis and genome analysis, and computer science research projects in such areas as job and data scheduling. The deployed infrastructure has been operating since November 2003 with 27 sites, a peak of 2800 processors, work loads from 10 different applications exceeding 1300 simultaneous jobs, and data transfers among sites of greater than 2 TB/day. We describe the principles that have guided the development of this unique infrastructure and the practical experiences that have resulted from its creation and use. We discuss application requirements for grid services deployment and configur...

  13. Improved Gridded Aerosol Data for India

    Energy Technology Data Exchange (ETDEWEB)

    Gueymard, C. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sengupta, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2013-11-01

    Using point data from ground sites in and around India equipped with multiwavelength sunphotometers, as well as gridded data from space measurements or from existing aerosol climatologies, an improved gridded database providing the monthly aerosol optical depth at 550 nm (AOD550) and Angstrom exponent (AE) over India is produced. Data from 83 sunphotometer sites are used here as ground truth tocalibrate, optimally combine, and validate monthly gridded data during the period from 2000 to 2012.

  14. Grid reliability

    Science.gov (United States)

    Saiz, P.; Andreeva, J.; Cirstoiu, C.; Gaidioz, B.; Herrala, J.; Maguire, E. J.; Maier, G.; Rocha, R.

    2008-07-01

    Thanks to the Grid, users have access to computing resources distributed all over the world. The Grid hides the complexity and the differences of its heterogeneous components. In such a distributed system, it is clearly very important that errors are detected as soon as possible, and that the procedure to solve them is well established. We focused on two of its main elements: the workload and the data management systems. We developed an application to investigate the efficiency of the different centres. Furthermore, our system can be used to categorize the most common error messages, and control their time evolution.

  15. GOLIAH (Gaming Open Library for Intervention in Autism at Home): a 6-month single blind matched controlled exploratory study.

    Science.gov (United States)

    Jouen, Anne-Lise; Narzisi, Antonio; Xavier, Jean; Tilmont, Elodie; Bodeau, Nicolas; Bono, Valentina; Ketem-Premel, Nabila; Anzalone, Salvatore; Maharatna, Koushik; Chetouani, Mohamed; Muratori, Filippo; Cohen, David

    2017-01-01

    To meet the required hours of intensive intervention for treating children with autism spectrum disorder (ASD), we developed an automated serious gaming platform (11 games) to deliver intervention at home (GOLIAH) by mapping the imitation and joint attention (JA) subset of age-adapted stimuli from the Early Start Denver Model (ESDM) intervention. Here, we report the results of a 6-month matched controlled exploratory study. From two specialized clinics, we included 14 children (age range 5-8 years) with ASD and 10 controls matched for gender, age, sites, and treatment as usual (TAU). Participants from the experimental group received in addition to TAU four 30-min sessions with GOLIAH per week at home and one at hospital for 6 months. Statistics were performed using Linear Mixed Models. Children and parents participated in 40% of the planned sessions. They were able to use the 11 games, and participants trained with GOLIAH improved time to perform the task in most JA games and imitation scores in most imitation games. GOLIAH intervention did not affect Parental Stress Index scores. At end-point, we found in both groups a significant improvement for Autism Diagnostic Observation Schedule scores, Vineland socialization score, Parental Stress Index total score, and Child Behavior Checklist internalizing, externalizing and total problems. However, we found no significant change for by time × group interaction. Despite the lack of superiority of TAU + GOLIAH versus TAU, the results are interesting both in terms of changes by using the gaming platform and lack of parental stress increase. A large randomized controlled trial with younger participants (who are the core target of ESDM model) is now discussed. This should be facilitated by computing GOLIAH for a web platform. Trial registration Clinicaltrials.gov NCT02560415.

  16. Percutaneous left atrial appendage occlusion - treatment outcomes and 6 months of follow-up - a single-center experience.

    Science.gov (United States)

    Karczewski, Michał; Woźniak, Sebastian; Skowronek, Radomir; Burysz, Marian; Fischer, Marcin; Anisimowicz, Lech; Demkow, Marcin; Konka, Marek; Ogorzeja, Wojciech

    2016-06-01

    To present the results of treatment and evaluate 6 months of follow-up in a group of patients with non-valvular atrial fibrillation, who underwent the procedure of percutaneous left atrial appendage occlusion (PLAAO). Percutaneous left atrial appendage occlusion was performed in 34 patients with non-valvular atrial fibrillation and contraindications for oral anticoagulation therapy. The risk of thromboembolic and bleeding complications was determined based on the CHA2DS2VASc and HAS-BLED scales. The Amplatzer Amulet system from St. Jude Medical was used. On the first postoperative day, all patients were started on double antiplatelet therapy with 75 mg/day of acetylsalicylic acid (ASA) and 75 mg/day of clopidogrel (CLO). On the 30(th) postoperative day, the efficacy of the antiplatelet therapy was assessed with impedance aggregometry using a Multiplate analyzer (Roche). Echocardiographic examinations were performed intraoperatively and on the first postoperative day; subsequently, follow-up examinations were conducted 1 and 6 months after the implantation. In all patients, proper occluder position was observed throughout the follow-up. No leakage or thrombi around the implants were found. No strokes or bleeding complications associated with the antiplatelet therapy were observed. Multiplate assessment of platelet activity was conducted in 20 out of 34 patients. The efficacy of ASA treatment was demonstrated in all patients; no response to clopidogrel treatment was observed in 5 out of 20 patients. One patient suffered from cardiac tamponade, which required the performance of full sternotomy. Local complications (hematomas of the inguinal region) were observed in 3 patients. One of the patients died for reasons unrelated to the procedure. Percutaneous left atrial appendage occlusion is an effective procedure in patients with non-valvular atrial fibrillation and contraindications for chronic anticoagulation therapy. Further observation is necessary to evaluate the

  17. Equivalent Simplification Method of Micro-Grid

    Directory of Open Access Journals (Sweden)

    Cai Changchun

    2013-09-01

    Full Text Available The paper concentrates on the equivalent simplification method for the micro-grid system connection into distributed network. The equivalent simplification method proposed for interaction study between micro-grid and distributed network. Micro-grid network, composite load, gas turbine synchronous generation, wind generation are equivalent simplification and parallel connect into the point of common coupling. A micro-grid system is built and three phase and single phase grounded faults are performed for the test of the equivalent model of micro-grid. The simulation results show that the equivalent model of micro-grid is effective, and the dynamic of equivalent model is similar with the detailed model of micro-grid. The equivalent simplification method for the micro-grid network and distributed components is suitable for the study of micro-grid.  

  18. A single 24 h recall overestimates exclusive breastfeeding practices among infants aged less than six months in rural Ethiopia.

    Science.gov (United States)

    Fenta, Esete Habtemariam; Yirgu, Robel; Shikur, Bilal; Gebreyesus, Seifu Hagos

    2017-01-01

    Exclusive breastfeeding (EBF) to six months is one of the World Health Organization's (WHOs) infant and young child feeding (IYCF) core indicators. Single 24 h recall method is currently in use to measure exclusive breastfeeding practice among children of age less than six months. This approach overestimates the prevalence of EBF, especially among small population groups. This justifies the need to look for alternative measurement techniques to have a valid estimate regardless of population characteristics. The study involved 422 infants of age less than six months, living in Gurage zone, Southern Ethiopia. The study was conducted from January to February 2016. Child feeding practices were measured for seven consecutive days using 24 h recall method. Recall since birth, was used to measure breastfeeding practices from birth to the day of data collection. Data on EBF obtained by using single 24 h recall were compared with seven days repeated 24 h recall method. McNemar's test was done to assess if a significant difference existed in rates of EBF between measurement methods. The mean age of infants in months was 3 (SD -1.43). Exclusive breastfeeding prevalence was highest (76.7%; 95% CI 72.6, 80.8) when EBF was estimated using single 24 h recall. The prevalence of EBF based on seven repeated 24 h recall was 53.2% (95% CI: 48.3, 58.0). The estimated prevalence of EBF since birth based on retrospective data (recall since birth) was 50.2% (95% CI 45.4, 55.1). Compared to the EBF estimates obtained from seven repeated 24 h recall, single 24 h recall overestimated EBF magnitude by 23 percentage points (95% CI 19.2, 27.8). As the number of days of 24 h recall increased, a significant decrease in overestimation of EBF was observed. A significant overestimation was observed when single 24 h recall was used to estimate prevalence of EBF compared to seven days of 24 h recall. By increasing the observation days we can significantly decrease the degree of

  19. Equivalent Simplification Method of Micro-Grid

    OpenAIRE

    Cai Changchun; Cao Xiangqin

    2013-01-01

    The paper concentrates on the equivalent simplification method for the micro-grid system connection into distributed network. The equivalent simplification method proposed for interaction study between micro-grid and distributed network. Micro-grid network, composite load, gas turbine synchronous generation, wind generation are equivalent simplification and parallel connect into the point of common coupling. A micro-grid system is built and three phase and single phase grounded faults are per...

  20. A Novel Single-Phase Grid-Connected Photovoltaic Inverter Without Isolation Transformer%新型的无隔离变压器单相光伏并网逆变器

    Institute of Scientific and Technical Information of China (English)

    吴学智; 尹靖元; 杨捷; 童亦斌

    2013-01-01

    提出了一种采用双级无隔离变压器的新型单相光伏并网逆变器拓扑,由于光伏池板与电网零线直接相连,可消除光伏池板对地的共模电压,解决了共模漏电流问题。所提拓扑采用了高频倍压的方式实现升压变换器与并网逆变器的连接,避免了三电平并网逆变器存在的中点电位二次脉动问题,降低了直流侧滤波电容的容量需求。为实现对单相并网电流的无误差控制,并网控制中采用比例谐振控制器,增加了系统的稳定性和提高了并网电流质量。仿真与实验结果均表明所提光伏并网逆变器拓扑的可行性。%The topology of a novel single-phase two-stage grid-connected Photovoltaic (PV) inverter without isolation transformer is proposed. The direct connection of PV panels with the zero line of power grid can eliminate the common mode voltage of PV panel to the ground, so the problem of common mode leakage current is solved. In the proposed topology the high-frequency voltage-doubling mode is utilized for the connection of boost converter with grid-connected inverter to avoid the secondary pulsation of neutral point potential existing in three-level grid-connected inverter, thus the demand on the capacity of filter capacitor at DC side is reduced. To implement the astatic control of single-phase grid-connected current, the proportional-resonant (PR) controller is adopted in the grid-connection control to enhance the stability of control system and improve the quality of grid-connected current. Results of simulation and experiments show that the topology of the proposed grid-connected PV inverter is feasible.

  1. HIRENASD NLR grid

    Data.gov (United States)

    National Aeronautics and Space Administration — Structured multiblock grid of HIRENASD wing with medium grid density, about 10 mill grid points, 9.5 mill cells. Starting from coarse AIAA AEPW structured grid,...

  2. Grid reliability

    CERN Document Server

    Saiz, P; Rocha, R; Andreeva, J

    2007-01-01

    We are offering a system to track the efficiency of different components of the GRID. We can study the performance of both the WMS and the data transfers At the moment, we have set different parts of the system for ALICE, ATLAS, CMS and LHCb. None of the components that we have developed are VO specific, therefore it would be very easy to deploy them for any other VO. Our main goal is basically to improve the reliability of the GRID. The main idea is to discover as soon as possible the different problems that have happened, and inform the responsible. Since we study the jobs and transfers issued by real users, we see the same problems that users see. As a matter of fact, we see even more problems than the end user does, since we are also interested in following up the errors that GRID components can overcome by themselves (like for instance, in case of a job failure, resubmitting the job to a different site). This kind of information is very useful to site and VO administrators. They can find out the efficien...

  3. Single- phase Double- stage Photovoltaic Grid- connected System and IsSpice Simulation%单相双极式光伏并网系统及IsSpice仿真

    Institute of Scientific and Technical Information of China (English)

    孙国凯; 商娜; 边雪芬

    2011-01-01

    分析了单相双极式光伏并网系统的结构和工作原理,通过分析光伏电池的特性,采用了一种改进的扰动观察法来实现高效跟踪光伏电池的最大功率点,将消谐性能较好的(SH-PWM)逆变技术应用到光伏并网系统中,有效改善了输出电流的质量.以DSP为核心设计了光伏并网控制系统,该系统包含了最大功率跟踪(MPPT),并网控制等部分,最后应用IsSpice仿真软件对系统进行仿真,结果表明所设计的光伏并网系统工作稳定,输出电流波形比一般逆变器有显著改善.%The structure and working principle of the single - phase double - stage photovoltaic (PV) grid - connected system are analyzed. The PV system tracks the maximum power point more efficiently and rapidly by an improved perturb and observe method. The applications of( SH - PWM ) inverting - tech in photovoltaic (PV) grid - connected system,which is better in harmonic cancellation,improve the electric current's quality. The PV grid- connected system which takes DSP as the core includes maximum power point tracking (MPPT), grid -connection control and insulate etc. The system has been simulated with the software IsSpice which shows that the single - phase double - stage photovoltaic (PV) grid - connected system can work stably. The electric current waveforms from five - level PWM inverter are better than the conventional inverter.

  4. Single-Phase Photovoltaic Grid-Connected Inverter under Constant-Frequency Hysteresis Current Control%恒频滞环电流控制的单相光伏并网逆变器

    Institute of Scientific and Technical Information of China (English)

    刘俊杰; 张新燕

    2012-01-01

    Based on the mathematical models of photovoltaic module practical in engineering,the module simulation model is established in PSIM software for the output quickly and dynamically changing with light intensity and temperature, and the output electrical characteristics of the PV module is analyzed by simulation.Meanwhile an algorithm is proposed to achieve MPPT,and its validity has been verified.Grid-connected inverter is a key electrical element of grid-connected PV system,influencing power quality and system stability.The grid-connected inverter under constantfrequency hysteresis current control is adopted,and the dynamic simulation model is built for the grid-connected singlephase PV system.The simulation results verify that the single-phase PV grid-connected inverter under constant-frequency hysteresis current control can track public grid quickly and effectively,output grid-connected current with low harmonic distortion rate,and enhance the stability and dynamism of grid-connected PV system,as well as its output efficiency.%基于符合工程实际的光伏模块数学模型,在PSIM软件中建立输出能快速动态随光照强度与温度变化的模块仿真模型,通过仿真分析光伏模块的输出电气特性。同时提出一种实现模块最大功率跟踪算法,并验证其有效性。光伏并网发电系统中的关键部件并网逆变器,影响电能质量与系统稳定。采用恒频滞环电流跟踪控制下的并网逆变器,建立单相光伏并网发电系统的动态仿真模型,仿真结果验证了恒频滞环电流控制光伏并网逆变器能够快速有效地跟踪公共电网,输出谐波畸变率低的并网电流,改善并网系统稳定性与动态性,提高光伏系统输出效率。

  5. Secondary emission monitor (SEM) grids.

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    A great variety of Secondary Emission Monitors (SEM) are used all over the PS Complex. At other accelerators they are also called wire-grids, harps, etc. They are used to measure beam density profiles (from which beam size and emittance can be derived) in single-pass locations (not on circulating beams). Top left: two individual wire-planes. Top right: a combination of a horizontal and a vertical wire plane. Bottom left: a ribbon grid in its frame, with connecting wires. Bottom right: a SEM-grid with its insertion/retraction mechanism.

  6. Single measurement of serum 25(OH)D: is classification into month-specific cutpoints useful in accounting for seasonal variation?

    Science.gov (United States)

    Saliba, W; Barnett-Griness, O; Rennert, G

    2012-09-01

    Classification into month-specific cutpoints is used to minimize misclassification associated with single measurement of serum 25(OH)D. This study aims to evaluate this strategy, and to compare it with the widely used classification into overall cutpoints. For this purpose, we studied 69,553 subjects in whom serum 25(OH)D was tested on two different occasions. The level of agreement between the quartiles of the first and second tests was 43.8% between the month-specific quartiles and 43.1% between the overall quartiles. The level of agreement between the quartiles of the two approaches was 80.0% and 94.3% in the first and second test, respectively. The extent of seasonal variation (summer-autumn as compared with winter-spring) of serum 25(OH)D was higher in males and in Jews, inversely associated with baseline levels, body mass index and age, and directly associated with socioeconomic class. The month-specific cutpoint strategy does not seem to offer advantage over the overall cutpoints strategy.

  7. OGC and Grid Interoperability in enviroGRIDS Project

    Science.gov (United States)

    Gorgan, Dorian; Rodila, Denisa; Bacu, Victor; Giuliani, Gregory; Ray, Nicolas

    2010-05-01

    the OGC Web service protocols, the advantages offered by the Grid technology - such as providing a secure interoperability between the distributed geospatial resource -and the issues introduced by the integration of distributed geospatial data in a secure environment: data and service discovery, management, access and computation. enviroGRIDS project proposes a new architecture which allows a flexible and scalable approach for integrating the geospatial domain represented by the OGC Web services with the Grid domain represented by the gLite middleware. The parallelism offered by the Grid technology is discussed and explored at the data level, management level and computation level. The analysis is carried out for OGC Web service interoperability in general but specific details are emphasized for Web Map Service (WMS), Web Feature Service (WFS), Web Coverage Service (WCS), Web Processing Service (WPS) and Catalog Service for Web (CSW). Issues regarding the mapping and the interoperability between the OGC and the Grid standards and protocols are analyzed as they are the base in solving the communication problems between the two environments: grid and geospatial. The presetation mainly highlights how the Grid environment and Grid applications capabilities can be extended and utilized in geospatial interoperability. Interoperability between geospatial and Grid infrastructures provides features such as the specific geospatial complex functionality and the high power computation and security of the Grid, high spatial model resolution and geographical area covering, flexible combination and interoperability of the geographical models. According with the Service Oriented Architecture concepts and requirements of interoperability between geospatial and Grid infrastructures each of the main functionality is visible from enviroGRIDS Portal and consequently, by the end user applications such as Decision Maker/Citizen oriented Applications. The enviroGRIDS portal is the single way

  8. Six-month visual outcomes for the correction of presbyopia using a small-aperture corneal inlay: single-site experience

    Directory of Open Access Journals (Sweden)

    Moshirfar M

    2016-11-01

    Full Text Available Majid Moshirfar,1,2 Tyler S Quist,3 David F Skanchy,4 Ryan T Wallace,5 Steven H Linn,1 Phillip C Hoopes Jr1 1Hoopes, Durrie, Rivera Research Center, Hoopes Vision, Draper, 2Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah School of Medicine, Salt Lake City, 3University of Utah School of Medicine, Salt Lake City, UT, 4McGovern Medical School, The University of Texas Health Science Center at Houston, TX, 5Brigham Young University, Provo, UT, USA Objective: The objective of this study was to describe 6-month postoperative efficacy and safety outcomes after monocular KAMRA corneal inlay implantation in emmetropic presbyopic patients. Study design: This study followed a retrospective chart analysis. Setting: This study was performed at Hoopes Vision in Draper, UT, USA. Subjects and methods: Fifty-seven patients met the inclusion criteria of this study and underwent KAMRA corneal inlay implantation following the approval of the United States Food and Drug Association between May 2015 and April 2016 at a single site. Surgery involved femtosecond laser-created corneal pockets of various depths. Efficacy, safety, and patient satisfaction reports were analyzed at 3 and 6 months. Results: At 6 months follow-up, the monocular uncorrected near visual acuity (UNVA was Jaeger (J 4 (20/32, the mean uncorrected distance visual acuity was 20/25, and the mean corrected distance visual acuity was 20/20. At 6 months, 71% of patients with a pocket depth of ≥250 µm had a UNVA of 20/20 or better, whereas only 22% of patients with a shallow pocket depth of <250 µm had a UNVA of 20/20 or better. There was no statistical difference in UNVA at 6 months between virgin eyes and post-LASIK eyes. One patient had an explant and five patients underwent inlay recentration, all of which resulted in improved visual acuity. At 6 months, 72% of patients reported some level of satisfaction, 26% of patients reported being

  9. Second Order Generalized Integrator Based Reference Current Generation Method for Single-Phase Shunt Active Power Filters Under Adverse Grid Conditions

    DEFF Research Database (Denmark)

    Golestan, Saeed; Monfared, Mohammad; Guerrero, Josep M.

    2013-01-01

    design procedure based on the pole-zero cancellation, and the extended symmetrical optimum theory is proposed. During the design procedure, the effects of grid frequency variations and the presence of distortion in the grid voltage are taken into account. Finally, to confirm the effectiveness......The reference current generation (RCG) is a crucial part in the control of a shunt active power filter (APF). A variety of RCG techniques have been proposed in literature. Among these, the instantaneous reactive power theory, called pq theory, is probably the most widely used technique. The pq...

  10. Research and Simulation of Single-phase Photovohaic Grid-connected Inverter Deadbeat Control%单相光伏并网逆变器无差拍控制的研究与仿真

    Institute of Scientific and Technical Information of China (English)

    闫洪林; 公茂法; 王静静; 曲敬文; 王晓愚; 商新朋

    2012-01-01

    PV grid-connected inverter is the main component of photovoltaic power generation system, fast and effective control in order to achieve better efficiency of the output of a higher quality of electrici- ty,the inverter current is particularly critical.This paper briefly describes the current photovoltaic grid-connected inverter of several commonly used control method and its basic idea of grid-connected inverter,working principle and the principle of deadbeat control,given the pulse width of the inverter cal- culation and the reference current for MATLAB/Simulink software simulation results show that,deadbeat control in single-phase photovoltaic grid-connected inverter control in the dynamic response charac- teristics of a good,simple control grid current waveform.%光伏并网逆变器是光伏发电系统的主要部件,为了达到更好的效率输出更高质量的电能,对逆变器电流进行快速有效的控制尤为关键。该文简单介绍了当前光伏并网逆变器的几种常用控制方法及其基本思想,分析了并网逆变器的工作原理和无差拍控制方法的原理,给出了逆变器脉冲宽度的计算和参考电流的获取方法,通过MATLAB/Simulink软件仿真表明,无差拍控制在单相光伏并网逆变器控制中动态响应特性好,控制方便,电流跟踪电网电压波形好。

  11. Single-phase Photovoltaic Grid-connected Inverter Based on Improved Phase-locked-loop%基于改进锁相环的单相光伏并网逆变器研制

    Institute of Scientific and Technical Information of China (English)

    杨恢宏; 沈定坤; 蒋怀贞; 翟登辉

    2011-01-01

    This paper presents an improved Software Phase-locked-loop(SPLL) algorithm for a single phase photovoltaic grid-connected inverter which arrays synchronizing a sinusoidal current output with a voltage grid. Through a phase delay , two orthogonal voltage in stationary coordinate system are generated, virtual d, q coordinate transformation is employed, the phase and frequency of grid voltage is obtained and the computing speed of PLL is improved.For achieving zero steady state error of current inner loop, quasi-proportion resonant (PR) controller is applied, voltage outer loop employs proportion integeral(PI) controller. Finally, simulation analysis based on Matlab and construction of single-phase grid-connected inverter confirm the theory feasibility of the method.%介绍了一种应用于单相光伏并网逆变器的改进型软件锁相环算法,可使逆变器输出电流与电网电压同步.将电网电压通过相位延迟,得到静止坐标系下2个正交电压,采用虚拟d,q坐标变换,经过一系列处理后,得到电网电压的相位及频率,提高了锁相速度,消除了谐波干扰,快速锁定任意频率和幅值电网电压的相位和频率.利用准比例谐振(PR)控制器对电流内环进行跟踪,实现了无静差调节,外环采用PI调节器.最后,通过Matlab仿真及样机实验分别验证了基于改进软件锁相环的单相并网逆变器的可行性.

  12. Results of fractional ablative facial skin resurfacing with the erbium:yttrium-aluminium-garnet laser 1 week and 2 months after one single treatment in 30 patients.

    Science.gov (United States)

    Trelles, Mario A; Mordon, Serge; Velez, Mariano; Urdiales, Fernando; Levy, Jean Luc

    2009-03-01

    The erbium:yttrium-aluminium-garnet (Er:YAG) laser has recently been used in the fractional resurfacing of photo-aged skin. Our study evaluated the results after one single session of fractional resurfacing with Er:YAG. Thirty women participated in the study, with an average age of 46 years, skin types from II to IV, and wrinkle grades I to III. The 2,940 nm Er:YAG system used (Pixel, Alma Laser, Israel) had variable pulse durations (1 ms to 2 ms) and energy densities (800 mJ/cm(2) to 1,400 mJ/cm(2)) which, together with the number of passes (four to eight), were selected as a function of wrinkle severity. All patients received only one treatment. Postoperative side effects were evaluated. The number of wrinkles was documented with clinical photography and was scored. Histological assessment was carried out on two patients before and 2 months after treatment. All patients completed the study. Of the patients, 93% reported good or very good improvement of the degree of their wrinkles, with a satisfaction index of 83%. Pain was not a problem during treatment, and there were no side effects except for in one phototype IV patient, who had hyperpigmentation. Histology 2 months after the single treatment demonstrated younger morphology of both the epidermis and dermis, with improvement of the pretreatment typical elastotic appearance. At the parameters used in our study, only one treatment session of Er:YAG laser could achieve effective skin rejuvenation, with effects recognized in both the dermis and, more importantly, the epidermis. This regimen offers an interesting alternative to the conventional approach of multi-session fractional resurfacing.

  13. Thyroxine clearance in rats within the first month after the single whole-body {gamma} - irradiation at a dose of 10Gy

    Energy Technology Data Exchange (ETDEWEB)

    Pryadko, Kirill A. [Institute of Radiobiology, National Academy of Sciences, Minsk (Belarus)

    2002-07-01

    The effects of acute whole-body {gamma} -irradiation at a dose of 10 Gy on thyroxine (T{sub 4}) plasma clearance rate (PCR) and thyroidal and blood T4 concentration ([T{sub 4}]) were examined within one month after exposure. The PCR values were measured using the bolus injection, single-compartmental approach. To eliminate the influence of radiation-induced anorexia animals were fasting for two days before the pharmacokinetic experiments. Hormone concentrations in blood and in thyroid tissue were measured by RIA. Throughout the observation period, PCR was elevated in irradiated rats with maximum at day 4 after exposure (0.56{+-}0.04 vs. 0.36{+-}0.03 ml/h100 gbw, P<0.001). [T{sub 4}] in blood was not significantly different from that in control animals. Thyroidal [T{sub 4}] was significantly decreased in irradiated animals 4 days after exposure (151.8{+-}21.7 vs. 258.8{+-}29.9 pmol/mg protein, P<0.01) and gradually increased after day 9. 10 Gy {gamma} -irradiation causes the intensification of T{sub 4} metabolism without the pronounced changes in concentration. Presumably, at early terms the rising local demand in O{sub 4} can not be compensated with the existing level of production. Alterations in the intensity of T{sub 4} metabolism are evident at least one month after exposure but they may not be detected without taking into account kinetic data.

  14. The MammoGrid Project Grids Architecture

    CERN Document Server

    McClatchey, R; Manset, D; Hauer, T; Estrella, F; Saiz, P; Rogulin, D; Clatchey, Richard Mc; Buncic, Predrag; Manset, David; Hauer, Tamas; Estrella, Florida; Saiz, Pablo; Rogulin, Dmitri

    2003-01-01

    The aim of the recently EU-funded MammoGrid project is, in the light of emerging Grid technology, to develop a European-wide database of mammograms that will be used to develop a set of important healthcare applications and investigate the potential of this Grid to support effective co-working between healthcare professionals throughout the EU. The MammoGrid consortium intends to use a Grid model to enable distributed computing that spans national borders. This Grid infrastructure will be used for deploying novel algorithms as software directly developed or enhanced within the project. Using the MammoGrid clinicians will be able to harness the use of massive amounts of medical image data to perform epidemiological studies, advanced image processing, radiographic education and ultimately, tele-diagnosis over communities of medical "virtual organisations". This is achieved through the use of Grid-compliant services [1] for managing (versions of) massively distributed files of mammograms, for handling the distri...

  15. Deliberate Secure Grid Computing Blueprint Design in Indian Context

    Directory of Open Access Journals (Sweden)

    Sanjeev Puri

    2012-06-01

    Full Text Available The novel concept of grid computing, clusters of computational power is constructed from a network of many small and widespread different computers servers or workstations into a single resource. We now proceed to translate the grid security problem into specific grid security requirements. The purpose of Grid technologies is to support the secure sharing and scalable coordinated use of diverse resources in dynamic, distributed VOs. We propose a secure blueprint design for grid systems that addresses requirements for single sign-on, interoperability with local policies of any grid city of India, with dynamically varying resource demands.

  16. Accurate Positioning of Femoral and Tibial Tunnels in Single Bundle Anterior Cruciate Ligament Reconstruction Using the Indigenously Made Bernard and Hurtle Grid on a Transparency Sheet and C-arm.

    Science.gov (United States)

    Kumar, Sudeep; Kumar, Anup; Kumar, Ravi

    2017-06-01

    Many factors determine the outcome of the anterior cruciate ligament reconstruction surgery. The single most important factor, also well within the control of a surgeon, is tunnel placement. It is difficult to accurately determine the center of the anterior cruciate ligament foot print, and many a times it is also difficult to accurately define the intercondylar and bifurcate ridge. This makes determination of the accurate entry point of the guidewire difficult. We have printed our indigenously formed grid (equidistant boxes) on an old-fashioned transparency sheet. We use a fluoroscopy (C-arm) shot intraoperatively in the lateral position and superimpose this sheet to determine the position of the guidewire by calculating the percentage of boxes. We aim at 27.7% in proximal to distal and 37.5% in anterior to posterior on the femur side and 45% in front to back and medial to lateral on the tibial side. C-arm is freely available, but the inbuilt grid facility may be available in only the higher version of C-arms. Our indigenously designed grid can be easily used across the globe with ease to achieve accuracy in tunnel placement without violating anatomy and without any extra cost.

  17. Introduction to grid computing

    CERN Document Server

    Magoules, Frederic; Tan, Kiat-An; Kumar, Abhinit

    2009-01-01

    A Thorough Overview of the Next Generation in ComputingPoised to follow in the footsteps of the Internet, grid computing is on the verge of becoming more robust and accessible to the public in the near future. Focusing on this novel, yet already powerful, technology, Introduction to Grid Computing explores state-of-the-art grid projects, core grid technologies, and applications of the grid.After comparing the grid with other distributed systems, the book covers two important aspects of a grid system: scheduling of jobs and resource discovery and monitoring in grid. It then discusses existing a

  18. Smart Grid Special; Smart Grid Special

    Energy Technology Data Exchange (ETDEWEB)

    Mokoginta, L. [Energiecooperatie ' Wij Krijgen Kippen' , Amsterdam (Netherlands); Messing, M. [Stichting Energietransitie Nederland, Boxtel (Netherlands); Slootweg, H. [Technische Universiteit Eindhoven TUE, Eindhoven (Netherlands); Van der Steen, L.; Brugman, L. [SquareWise, Amsterdam (Netherlands); Bles, M.; Blom, M. [CE Delft, Delft (Netherlands); Nachtegaal, H.; Hoekstra, R. [Bijl partners in public relations, Rotterdam (Netherlands); Van Zutphen, M. [CapGemini, Utrecht (Netherlands); Bakker, D. [PNO Consultants, Schiphol (Netherlands); Van Leeuwen, M. [Norton Rose, Amsterdam (Netherlands); Van Vlerken, J.; De Leeuw, M.; Wijnants, H.J.; Holwerda, B.; Bosch, N.

    2012-06-15

    A series of 17 articles is dedicated to various aspects of smart grids: expert opinions, the key role of smart grids in a sustainable energy transition, the role of the energy consumer and the grid operators, an energy transition project in the South of Amsterdam (Netherlands), the need for collaboration (e.g. through the Smart Energy Collective), the establishment of local energy corporations, the question whether smart grids are a hype or a necessity, costs and benefits of smart grids, deployment of intelligent smart grids in business areas (experimental areas), the opportunity of deploying Direct Current (DC) grids for an improved energy balance, the Smart Power City Apeldoorn project (SPCA), the experimental area of CloudPower on the isle of Texel, innovation contracts for smart grids, the increase of local, small-scale electricity production, and smart grid pilot projects on Europe. [Dutch] In 17 artikelen wordt aandacht besteed aan diverse aspecten van 'smart grids': meningen van experts, de sleutelrol van smart grids in een duurzame energietransitie, de rol van de energieconsument en de netbeheerders, een energietransitie-project in Amsterdam-Zuid, de noodzaak tot samenwerking (onder meer d.m.v. het Smart Energy Collective), de oprichting van lokale energiecooperaties, de vraag of smart grids een hype zijn of noodzaak, kosten en baten van smart grids, de toepassing van intelligente energienetwerken op bedrijventerreinen ('proeftuinen'), de mogelijkheid om gelijkspanningsnetten toe te passen voor een betere energiebalans, het project Smart Power City Apeldoorn (SPCA), de proeftuin CloudPower op Texel, innovatiecontracten m.b.t. smart grids, de toename van lokale, kleinschalige elektriciteitsproductie, smart grid demonstratieprojecten in Europa.

  19. Analysis on Common Mode Current of Single-Phase Grid-Connected PV System%单相光伏并网系统共模电流分析

    Institute of Scientific and Technical Information of China (English)

    杨秋霞; 高金玲; 荣雅君; 任玉艳

    2011-01-01

    Common mode current problem is very important to grid-connected photovoltaic (PV) system and in German standard DIN VDE 0126-1-1, the stipulations related to the common mode current are specified. When common mode current exceeds specified value, the connected PV generation system should be cut off within the stipulated time.Considering the importance of common mode current to the connection of photovoltaic generation to power grid, a common mode current is built. It is known throuth the analysis that common mode current is related to modulation technology and the position where the inductance locates. In allusion to above-mentioned features, a new single-phase grid-connected PV system that can suppress common mode current is designed.The designed system is a full-bridge single-phase gridconnected PV system with AC bypass circuit and in which inductances are symmetically arranged at both phase line and neutral line. Comparing with traditional full-bridge inverter systems adopting unipolar or bi-polar modulation technology,the structure of the proposed single-phase grid-connected PV system not only can eliminate common mode current produced in the grid-connected PV system, but also improve system efficiency and quality of current sent into power grid, thus the overall performance of the grid-connected PV system is improved. Results from theoretical analysis and simulation show that the proposed model and system are correct and available.%共模电流问题是光伏并网系统中的一个重要问题,德国DIN VDE 0126-1-1对共模电流做出了相关规定.当共模电流超过规定值时,系统必须在规定的时间内断开.考虑到共模电流在光伏并网系统中的重要性,建立了共模模型.通过分析可知,共模电流与调制技术和电感的安放位置相关.针对上述特点,设计了能够抑制共模电流的新型单相光伏并网系统,即带有交流旁路且电感对称分布在相线和中线上的全桥光伏并网系统.与传

  20. A single HIV-1 cluster and a skewed immune homeostasis drive the early spread of HIV among resting CD4+ cell subsets within one month post-infection.

    Science.gov (United States)

    Bacchus, Charline; Cheret, Antoine; Avettand-Fenoël, Véronique; Nembot, Georges; Mélard, Adeline; Blanc, Catherine; Lascoux-Combe, Caroline; Slama, Laurence; Allegre, Thierry; Allavena, Clotilde; Yazdanpanah, Yazdan; Duvivier, Claudine; Katlama, Christine; Goujard, Cécile; Seksik, Bao Chau Phung; Leplatois, Anne; Molina, Jean-Michel; Meyer, Laurence; Autran, Brigitte; Rouzioux, Christine

    2013-01-01

    Optimizing therapeutic strategies for an HIV cure requires better understanding the characteristics of early HIV-1 spread among resting CD4+ cells within the first month of primary HIV-1 infection (PHI). We studied the immune distribution, diversity, and inducibility of total HIV-DNA among the following cell subsets: monocytes, peripheral blood activated and resting CD4 T cells, long-lived (naive [TN] and central-memory [TCM]) and short-lived (transitional-memory [TTM] and effector-memory cells [TEM]) resting CD4+T cells from 12 acutely-infected individuals recruited at a median 36 days from infection. Cells were sorted for total HIV-DNA quantification, phylogenetic analysis and inducibility, all studied in relation to activation status and cell signaling. One month post-infection, a single CCR5-restricted viral cluster was massively distributed in all resting CD4+ subsets from 88% subjects, while one subject showed a slight diversity. High levels of total HIV-DNA were measured among TN (median 3.4 log copies/million cells), although 10-fold less (p = 0.0005) than in equally infected TCM (4.5), TTM (4.7) and TEM (4.6) cells. CD3-CD4+ monocytes harbored a low viral burden (median 2.3 log copies/million cells), unlike equally infected resting and activated CD4+ T cells (4.5 log copies/million cells). The skewed repartition of resting CD4 subsets influenced their contribution to the pool of resting infected CD4+T cells, two thirds of which consisted of short-lived TTM and TEM subsets, whereas long-lived TN and TCM subsets contributed the balance. Each resting CD4 subset produced HIV in vitro after stimulation with anti-CD3/anti-CD28+IL-2 with kinetics and magnitude varying according to subset differentiation, while IL-7 preferentially induced virus production from long-lived resting TN cells. In conclusion, within a month of infection, a clonal HIV-1 cluster is massively distributed among resting CD4 T-cell subsets with a flexible inducibility, suggesting that

  1. A single HIV-1 cluster and a skewed immune homeostasis drive the early spread of HIV among resting CD4+ cell subsets within one month post-infection.

    Directory of Open Access Journals (Sweden)

    Charline Bacchus

    Full Text Available Optimizing therapeutic strategies for an HIV cure requires better understanding the characteristics of early HIV-1 spread among resting CD4+ cells within the first month of primary HIV-1 infection (PHI. We studied the immune distribution, diversity, and inducibility of total HIV-DNA among the following cell subsets: monocytes, peripheral blood activated and resting CD4 T cells, long-lived (naive [TN] and central-memory [TCM] and short-lived (transitional-memory [TTM] and effector-memory cells [TEM] resting CD4+T cells from 12 acutely-infected individuals recruited at a median 36 days from infection. Cells were sorted for total HIV-DNA quantification, phylogenetic analysis and inducibility, all studied in relation to activation status and cell signaling. One month post-infection, a single CCR5-restricted viral cluster was massively distributed in all resting CD4+ subsets from 88% subjects, while one subject showed a slight diversity. High levels of total HIV-DNA were measured among TN (median 3.4 log copies/million cells, although 10-fold less (p = 0.0005 than in equally infected TCM (4.5, TTM (4.7 and TEM (4.6 cells. CD3-CD4+ monocytes harbored a low viral burden (median 2.3 log copies/million cells, unlike equally infected resting and activated CD4+ T cells (4.5 log copies/million cells. The skewed repartition of resting CD4 subsets influenced their contribution to the pool of resting infected CD4+T cells, two thirds of which consisted of short-lived TTM and TEM subsets, whereas long-lived TN and TCM subsets contributed the balance. Each resting CD4 subset produced HIV in vitro after stimulation with anti-CD3/anti-CD28+IL-2 with kinetics and magnitude varying according to subset differentiation, while IL-7 preferentially induced virus production from long-lived resting TN cells. In conclusion, within a month of infection, a clonal HIV-1 cluster is massively distributed among resting CD4 T-cell subsets with a flexible inducibility

  2. Spatially fractionated radiotherapy (GRID) using helical tomotherapy.

    Science.gov (United States)

    Zhang, Xin; Penagaricano, Jose; Yan, Yulong; Liang, Xiaoying; Morrill, Steven; Griffin, Robert J; Corry, Peter; Ratanatharathorn, Vaneerat

    2016-01-08

    Spatially fractionated radiotherapy (GRID) was designed to treat large tumors while sparing skin, and it is usually delivered with a linear accelerator using a commercially available block or multileaf collimator (LINAC-GRID). For deep-seated (skin to tumor distance (> 8 cm)) tumors, it is always a challenge to achieve adequate tumor dose coverage. A novel method to perform GRID treatment using helical tomotherapy (HT-GRID) was developed at our institution. Our approach allows treating patients by generating a patient-specific virtual GRID block (software-generated) and using IMRT technique to optimize the treatment plan. Here, we report our initial clinical experience using HT-GRID, and dosimetric comparison results between HT-GRID and LINAC-GRID. This study evaluates 10 previously treated patients who had deep-seated bulky tumors with complex geometries. Five of these patients were treated with HT-GRID and replanned with LINAC-GRID for comparison. Similarly, five other patients were treated with LINAC-GRID and replanned with HT-GRID for comparison. The prescription was set such that the maximum dose to the GTV is 20 Gy in a single fraction. Dosimetric parameters compared included: mean GTV dose (DGTV mean), GTV dose inhomogeneity (valley-to-peak dose ratio (VPR)), normal tissue doses (DNmean), and other organs-at-risk (OARs) doses. In addition, equivalent uniform doses (EUD) for both GTV and normal tissue were evaluated. In summary, HT-GRID technique is patient-specific, and allows adjustment of the GRID pattern to match different tumor sizes and shapes when they are deep-seated and cannot be adequately treated with LINAC-GRID. HT-GRID delivers a higher DGTV mean, EUD, and VPR compared to LINAC-GRID. HT-GRID delivers a higher DNmean and lower EUD for normal tissue compared to LINAC-GRID. HT-GRID plans also have more options for tumors with complex anatomical relationships between the GTV and the avoidance OARs (abutment or close proximity).

  3. Workload dynamics on clusters and grids

    NARCIS (Netherlands)

    Li, H.

    2009-01-01

    This paper presents a comprehensive statistical analysis of a variety of workloads collected on production clusters and Grids. The applications are mostly computational-intensive and each task requires single CPU for processing data, which dominate the workloads on current production Grid systems. T

  4. Is there a single spot size and grid for intensity modulated proton therapy? Simulation of head and neck, prostate and mesothelioma cases

    Energy Technology Data Exchange (ETDEWEB)

    Widesott, Lamberto; Lomax, Antony J.; Schwarz, Marco [AtreP, Agenzia Provinciale per la Protonterapia, 38122 Trento (Italy); Paul Scherrer Institute, 5232 Villigen (Switzerland); AtreP, Agenzia Provinciale per la Protonterapia, 38122 Trento (Italy)

    2012-03-15

    Purpose: To assess the quality of dose distributions in real clinical cases for different dimensions of scanned proton pencil beams. The distance between spots (i.e., the grid of delivery) is optimized for each dimension of the pencil beam. Methods: The authors vary the {sigma} of the initial Gaussian size of the spot, from {sigma}{sub x} = {sigma}{sub y} = 3 mm to {sigma}{sub x} = {sigma}{sub y} = 8 mm, to evaluate the impact of the proton beam size on the quality of intensity modulated proton therapy (IMPT) plans. The distance between spots, {Delta}x and {Delta}y, is optimized on the spot plane, ranging from 4 to 12 mm (i.e., each spot size is coupled with the best spot grid resolution). In our Hyperion treatment planning system (TPS), constrained optimization is applied with respect to the organs at risk (OARs), i.e., the optimization tries to satisfy the dose objectives in the planning target volume (PTV) as long as all planning objectives for the OARs are met. Three-field plans for a nasopharynx case, two-field plans for a prostate case, and two-field plans for a malignant pleural mesothelioma case are considered in our analysis. Results: For the head and neck tumor, the best grids (i.e., distance between spots) are 5, 4, 6, 6, and 8 mm for {sigma} = 3, 4, 5, 6, and 8 mm, respectively. {sigma} {<=} 5 mm is required for tumor volumes with low dose and {sigma}{<=} 4 mm for tumor volumes with high dose. For the prostate patient, the best grid is 4, 4, 5, 5, and 5 mm for {sigma} = 3, 4, 5, 6, and 8 mm, respectively. Beams with {sigma} > 3 mm did not satisfy our first clinical requirement that 95% of the prescribed dose is delivered to more than 95% of prostate and proximal seminal vesicles PTV. Our second clinical requirement, to cover the distal seminal vesicles PTV, is satisfied for beams as wide as {sigma} = 6 mm. For the mesothelioma case, the low dose PTV prescription is well respected for all values of {sigma}, while there is loss of high dose PTV coverage

  5. Smart Grid Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Craig [National Rural Electric Cooperative Association, Arlington, VA (United States); Carroll, Paul [National Rural Electric Cooperative Association, Arlington, VA (United States); Bell, Abigail [National Rural Electric Cooperative Association, Arlington, VA (United States)

    2015-03-11

    The National Rural Electric Cooperative Association (NRECA) organized the NRECA-U.S. Department of Energy (DOE) Smart Grid Demonstration Project (DE-OE0000222) to install and study a broad range of advanced smart grid technologies in a demonstration that spanned 23 electric cooperatives in 12 states. More than 205,444 pieces of electronic equipment and more than 100,000 minor items (bracket, labels, mounting hardware, fiber optic cable, etc.) were installed to upgrade and enhance the efficiency, reliability, and resiliency of the power networks at the participating co-ops. The objective of this project was to build a path for other electric utilities, and particularly electrical cooperatives, to adopt emerging smart grid technology when it can improve utility operations, thus advancing the co-ops’ familiarity and comfort with such technology. Specifically, the project executed multiple subprojects employing a range of emerging smart grid technologies to test their cost-effectiveness and, where the technology demonstrated value, provided case studies that will enable other electric utilities—particularly electric cooperatives— to use these technologies. NRECA structured the project according to the following three areas: Demonstration of smart grid technology; Advancement of standards to enable the interoperability of components; and Improvement of grid cyber security. We termed these three areas Technology Deployment Study, Interoperability, and Cyber Security. Although the deployment of technology and studying the demonstration projects at coops accounted for the largest portion of the project budget by far, we see our accomplishments in each of the areas as critical to advancing the smart grid. All project deliverables have been published. Technology Deployment Study: The deliverable was a set of 11 single-topic technical reports in areas related to the listed technologies. Each of these reports has already been submitted to DOE, distributed to co-ops, and

  6. 单相光伏并网发电系统功率解耦的优化设计%Optimal Design of Power Decoupling in Single-phase Grid-connected PV Systems

    Institute of Scientific and Technical Information of China (English)

    徐政; 林崇; 何少强

    2012-01-01

    As a nonlinear DC power source, a solar array should operate at the maximum power point with a stable DC power output. Otherwise, the power output of a single-phase grid connected system contains an AC component with double grid frequency. Corresponding to such difference of input and output characteristics in single-phase grid connected PV systems, the influences of power pulsation on maximum power point tracking (MPPT), transfer efficiency and power quality of inverter were synthetically studied. The comparison of different circuit topologies was made by theoretical analysis, computer simulation as well as experiment, and an optimal design rule of decoupling capacitors was proposed which can improve the system operating efficiency as well as standardize product design.%作为非线性直流电源,光伏阵列的理想运行状态是在最大功率点上输出稳定的直流功率,而单相并网发电系统的并网功率含有2倍于电网频率的交流量.针对单相光伏并网发电系统这种输入与输出特性的差异,综合研究了并网功率脉动对最大功率点跟踪特性、逆变器转换效率及并网电能质量的影响,通过理论分析、仿真计算和实验验证,比较不同电路拓扑的特性,提出了解耦电容的优化设计准则,提高了系统的运行效率,实现了产品设计的规范化.

  7. Clinical evaluation of a novel dental implant system as single implants under immediate loading conditions - 4-month post-loading results from a multicentre randomised controlled trial.

    Science.gov (United States)

    Esposito, Marco; Trullenque-Eriksson, Anna; Blasone, Rodolfo; Malaguti, Giuliano; Gaffuri, Cristiano; Caneva, Marco; Minciarelli, Armando; Luongo, Giuseppe

    To evaluate the safety and clinical effectiveness of a novel dental implant system (GENESIS Implant System, Keystone Dental, Massachusetts, USA) using another dental implant system by the same manufacturer as a control (PRIMA Implant System, Keystone Dental). A total of 53 patients requiring at least two single crowns had their sites randomised according to a split-mouth design to receive both implant systems at six centres. If implants could be placed with a torque superior to 40 Ncm they were to be loaded immediately with provisional crowns, otherwise after 3 months of submerged healing. Provisional crowns were replaced by definitive crowns 4 months after initial loading, when the follow-up period for the initial part of this study was completed. Outcome measures were crown/implant failures, complications, pink esthetic score (PES), peri-implant marginal bone level changes, plaque score, marginal bleeding, patients and preference of the clinician. In total 53 PRIMA and 53 GENESIS implants were placed. Three patients dropped out but all of the remaining patients were followed up to 4-months post-loading. No PRIMA implant failed whereas four GENESIS implants failed. Only two complications were reported for PRIMA implants. There were no statistically significant differences for crown/implant failures (difference in proportions = 0.080; P (McNemar test) = 0.125) and complications (difference in proportions = -0.04; P (McNemar test) = 0.500) between the implant systems. There were no differences at 4-months post-loading for plaque (difference = -0.54, 95% CI: -3.01 to 1.93; P (Paired t-test) = 0.660), marginal bleeding (difference = -3.8, 95% CI: -7.63 to 0.019; P (Paired t-test) = 0.051), PES (difference = 0.47, 95% CI: -0.56 to 1.50; P (Paired t-test) = 0.365) and marginal bone level changes (difference in mm = -0.04, 95% CI: -0.33 to 0.26; P (Paired t-test) = 0.795). The majority of the patients (46) had no

  8. Bayesian grid matching

    DEFF Research Database (Denmark)

    Hartelius, Karsten; Carstensen, Jens Michael

    2003-01-01

    A method for locating distorted grid structures in images is presented. The method is based on the theories of template matching and Bayesian image restoration. The grid is modeled as a deformable template. Prior knowledge of the grid is described through a Markov random field (MRF) model which...... nodes and the arc prior models variations in row and column spacing across the grid. Grid matching is done by placing an initial rough grid over the image and applying an ensemble annealing scheme to maximize the posterior distribution of the grid. The method can be applied to noisy images with missing...

  9. The Application of Cascade Signal Delay Cancellation in Single Phase Grid Synchronization Technology%CDSC 在单相电网同步锁相技术中的应用

    Institute of Scientific and Technical Information of China (English)

    孙立; 杨贵营; 庄圣贤; 李少阶; 严肃

    2014-01-01

    针对非理想电网环境下单相锁相环同步问题,文章提出一种基于级联信号延时消除(CDSC)的单相锁相环。研究中首先对仅有单相输入下的坐标变换结果进行分析,得出各种非理想电网状态下单相信号输入的同步旋转坐标变换的输出特性。结合带有频率反馈环路的级联信号延时消除法能够快速有效的抑制如直流分量、谐波、相位突变等非理想电网环境给同步参考坐标变换的输出带来不良影响,从而达到准确跟踪单相电网基波电压幅值、相位和频率自适应的目的。该方法无需构造单相电压信号的虚拟正交信号,算法简单且硬件上容易实现。仿真和实验结果验证所提锁相环在非理想电网环境下可以快速准确的跟踪输入电网电压信号的相位、频率和幅值,同时满足系统的稳定性。%A kind of single phase lock loop based on cascade signal delay cancellation has been proposed in this paper to deal with the single phase grid synchronization under non - ideal grid environment. Firstly,the coordinate transfor-mation results with only single phase signal is considered as the input signal has been analyzed,and the output fea-tures of synchronous rotation coordinate transformation with single phase signal as the input in every non - ideal grid environment will be obtained. The proposed method,combining the cascade signal delay elimination method with fre-quency feedback loop,will suppress the effect of non - ideal grid environment,like DC component,harmonic compo-nent,phase hits and so on,on synchronous reference coordinate transformation quickly and effectively,so as to track the voltage amplitude,phase of the single grid and frequency self - adaption accurately. Moreover,this method does not ask for virtual orthogonal signal construction,which will be implemented simply by hardware. The effectiveness of the proposed method is verified by simulation and experiment

  10. Monthly errors

    Data.gov (United States)

    U.S. Environmental Protection Agency — The 2006 monthly average statistical metrics for 2m Q (g kg-1) domain-wide for the base and MODIS WRF simulations against MADIS observations. This dataset is...

  11. Mapping of grid faults and grid codes

    DEFF Research Database (Denmark)

    Iov, F.; Hansen, Anca Daniela; Sørensen, Poul Ejnar

    for such investigations. The grid connection requirements for wind turbines have increased significantly during the last 5-10 years. Especially the requirements for wind turbines to stay connected to the grid during and after voltage sags, imply potential challenges in the design of wind turbines. These requirements pose...... challenges for the design of both the electrical system and the mechanical structure of wind turbines. An overview over the frequency of grid faults and the grid connection requirements in different relevant countries is done in this report. The most relevant study cases for the quantification of the loads......The present report is a part of the research project ''Grid fault and designbasis for wind turbine'' supported by Energinet.dk through the grant PSO F&U 6319. The objective of this project is to investigate into the consequences of the new grid connection requirements for the fatigue and extreme...

  12. Mapping of grid faults and grid codes

    DEFF Research Database (Denmark)

    Iov, Florin; Hansen, A.D.; Sørensen, P.

    The present report is a part of the research project "Grid fault and design basis for wind turbine" supported by Energinet.dk through the grant PSO F&U 6319. The objective of this project is to investigate into the consequences of the new grid connection requirements for the fatigue and extreme...... for such investigations. The grid connection requirements for wind turbines have increased significantly during the last 5-10 years. Especially the requirements for wind turbines to stay connected to the grid during and after voltage sags, imply potential challenges in the design of wind turbines. These requirements pose...... challenges for the design of both the electrical system and the mechanical structure of wind turbines. An overview over the frequency of grid faults and the grid connection requirements in different relevant countries is done in this report. The most relevant study cases for the quantification of the loads...

  13. 准单级单向Buck直流变换器型高频链并网逆变器%Quasi single-stage unidirectional Buck DC-DC converter mode grid-connected inverters with high frequency link

    Institute of Scientific and Technical Information of China (English)

    陈道炼; 严斌; 陈峰; 左巧安; 林真

    2012-01-01

    A circuit configuration and circuit topological family of quasi single-stage unidirectional buck dc-dc converter mode grid-connected inverters with high frequency link are proposed in this paper. Its circuit configuration is composed of the unidirectional isolated buck dc-dc converter and polarity reversal inverting bridge, and its circuit topology includes single-transistor forward, interleaving single-transistor forward, push-pull, push-pull forward, two-transistor forward, interleaving two-transistor forward, half-bridge, and full-bridge mode circuit. The circuit topology, instantaneous current control strategy, steady principle properties, and design criteria for the key circuit parameters were deeply investigated. Taking push-pull forward mode topology as an example, 1 kW 48VDC/220V50 HzAC grid-connected inverter prototype was developed. The research results show that this kind of inverter has the advantages such as high frequency electrical isolation, simple topology, quasi single-stage conversion, high conversion efficiency , the polarity reversal inverting bridge' s power switches having low voltage stress and ZVZCS, high quality grid-connected current etc.%提出准单级单向Buck直流变换器型高频链并网逆变器电路结构与拓扑族.其电路结构是由单向隔离Buck直流变换器和极性反转逆变桥级联构成;其拓扑族包括推挽正激式、双管正激式、并联交错双管正激式、半桥式和全桥式电路.深入分析研究类逆变器的电路拓扑、电流瞬时值控制策略、稳态原理特性和关键电路参数设计准则.以推挽正激式拓扑为例,设计并研制出1kW48VDC/220V50HzAC并网逆变器样机.研究结果表明,此类逆变器具有高频电气隔离、电路结构简洁、准单级功率变换、变换效率高、极性反转逆变桥功率开关电压应力低且为ZVZCS、并网电流质量高等优点.

  14. Pharmacokinetic comparison of acetaminophen elixir versus suppositories in vaccinated infants (aged 3 to 36 months): a single-dose, open-label, randomized, parallel-group design.

    Science.gov (United States)

    Walson, Philip D; Halvorsen, Mark; Edge, James; Casavant, Marcel J; Kelley, Michael T

    2013-02-01

    Because of practical problems and ethical concerns, few studies of the pharmacokinetics (PK) of acetaminophen (ACET) in infants have been published. The goal of this study was to compare the PK of an ACET rectal suppository with a commercially available ACET elixir to complete a regulatory obligation to market the suppository. This study was not submitted previously because of numerous obstacles related to both the investigators and the commercial entities associated with the tested product. Thirty infants (age 3-36 months) prescribed ACET for either fever, pain, or postimmunization prophylaxis of fever and discomfort were randomized to receive a single 10- to 15-mg/kg ACET dose either as the rectal suppository or oral elixir. Blood was collected at selected times for up to 8 hours after administration. ACET concentrations were measured by using a validated HPLC method, and PK behavior and bioavailability were compared for the 2 preparations. All 30 infants enrolled were prescribed ACET for postimmunization prophylaxis. PK samples were available in 27 of the 30 enrolled infants. Subject enrollment (completed in January 1995) was rapid (8.3 months) and drawn entirely from a vaccinated infant clinic population. There were no statistically significant differences between the subjects (elixir, n = 12; suppository, n = 15) in either mean (SD) age (10.0 [6.3] vs 12.4 [8.1] months), weight (8.6 [2.3] vs 9.4 [2.4] kg), sex (7 of 12 males vs 7 of 15 males), or racial distribution (5 white, 5 black, and 2 biracial vs 4 white and 11 black) between the 2 dosing groups (oral vs rectal, respectively). The oral and rectal preparations produced similar, rapid peak concentrations (T(max), 1.16 vs 1.17 hours; P = 0.98) and elimination t(½) (1.84 vs 2.10 hours; P = 0.14), respectively. No statistically significant differences were found between either C(max) (7.65 vs 5.68 μg/mL) or total drug exposure (AUC(0-∞), 23.36 vs 20.45 μg-h/mL) for the oral versus rectal preparations

  15. Parallel grid population

    Science.gov (United States)

    Wald, Ingo; Ize, Santiago

    2015-07-28

    Parallel population of a grid with a plurality of objects using a plurality of processors. One example embodiment is a method for parallel population of a grid with a plurality of objects using a plurality of processors. The method includes a first act of dividing a grid into n distinct grid portions, where n is the number of processors available for populating the grid. The method also includes acts of dividing a plurality of objects into n distinct sets of objects, assigning a distinct set of objects to each processor such that each processor determines by which distinct grid portion(s) each object in its distinct set of objects is at least partially bounded, and assigning a distinct grid portion to each processor such that each processor populates its distinct grid portion with any objects that were previously determined to be at least partially bounded by its distinct grid portion.

  16. Intelligent geospatial data retrieval based on the geospatial grid portal

    Science.gov (United States)

    Yuan, Jie; Yue, Peng; Gong, Jianya

    2008-12-01

    The Open Geospatial Consortium (OGC) standard-compliant services define a set of standard interfaces for geospatial Web services to achieve the interoperability in an open distributed computing environment. Grid technology is a distributed computing infrastructure to allow distributed resources sharing and coordinated problem solving. Based on the OGC standards for geospatial services and grid technology, we propose the geospatial grid portal to integrate and interoperate grid-enabled geospatial services. The implementation of the geospatial grid portal is based on a three-tier architecture which consists of grid-enabled geospatial services tier, grid service portal tier and application tier. The OGC standard-compliant services are deployed in a grid environment, the so-called grid-enabled geospatial services. Grid service portals for each type of geospatial services, including WFS, WMS, WCS and CSW, provide a single point of Web entry to discover and access different types of geospatial information. A resource optimization mechanism is incorporated into these service portals to optimize the selection of grid nodes. At the top tier, i.e. the application tier, the client interacts with a semantic middleware for the grid CSW portal, thus allows the semantics-enabled search. The proposed approach can not only optimize the grid resource selection among multiple grid nodes, but also incorporate the power of Semantic Web technology into geospatial grid portal to allow the precise discovery of geospatial data.

  17. Smart grid security

    CERN Document Server

    Goel, Sanjay; Papakonstantinou, Vagelis; Kloza, Dariusz

    2015-01-01

    This book on smart grid security is meant for a broad audience from managers to technical experts. It highlights security challenges that are faced in the smart grid as we widely deploy it across the landscape. It starts with a brief overview of the smart grid and then discusses some of the reported attacks on the grid. It covers network threats, cyber physical threats, smart metering threats, as well as privacy issues in the smart grid. Along with the threats the book discusses the means to improve smart grid security and the standards that are emerging in the field. The second part of the b

  18. Phase-lock loop of Grid-connected Voltage Source Converter under non-ideal grid condition

    DEFF Research Database (Denmark)

    Wang, Haojie; Sun, Hai; Han, Minxiao;

    2015-01-01

    phase information cannot be accurately tracked. Based on analysis of the cause of double-frequency ripple when unbalance exists in main grid, a phase-locked loop (PLL) detection technique is proposed. Under the conditions of unsymmetrical system voltage, varying system frequency, single-phase system......It is a normal practice that the DC micro-grid is connected to AC main grid through Grid-connected Voltage Source Converter (G-VSC) for voltage support. Accurate control of DC micro-grid voltage is difficult for G-VSC under unbalanced grid condition as the fundamental positive-sequence component...

  19. REVIEW ON GRID INTERFACING OF MULTIMEGAWATT PHOTOVOLTAIC INVERTERS

    OpenAIRE

    2016-01-01

    This paper presents review on the latest development of control of grid connected photovoltaic energy conversion system. Also this paper present existing systems control algorithm for three-phase and single phase grid-connected photovoltaic (PV) system.  This paper focuses on one aspect of solar energy, namely grid interfacing of large-scale PV farms. This Grid-connected photovoltaic  i.e. PV systems can provide a number of benefits to electric utilities, such as power loss reductio...

  20. ENERGY LOSS REDUCTION IN SMART GRID UTILITIES FOR ACCOUNT OF TRANSITION FROM SINGLE-PHASE TO THREE-PHASE POWER DISTRIBUTION SYSTEMS

    Directory of Open Access Journals (Sweden)

    G.G. Zhemerov

    2014-10-01

    Full Text Available Analytical dependences of such efficiency indices as energy loss power and copper consumption under transition from single-phase power distribution systems to three-phase ones are obtained.

  1. RSW Modified Inflow Grid

    Data.gov (United States)

    National Aeronautics and Space Administration — After discussions by the organizing committee, and some research using the RSW grids, a modification has been made on the RSW grids. The inflow boundary has now been...

  2. HIRENASD coarse structured grid

    Data.gov (United States)

    National Aeronautics and Space Administration — blockstructured hexahedral grid, 6.7 mio elements, 24 degree minimum grid angle, CGNS format version 2.4, double precision Binary, Plot3D file Please contact...

  3. GRID2D/3D: A computer program for generating grid systems in complex-shaped two- and three-dimensional spatial domains. Part 1: Theory and method

    Science.gov (United States)

    Shih, T. I.-P.; Bailey, R. T.; Nguyen, H. L.; Roelke, R. J.

    1990-01-01

    An efficient computer program, called GRID2D/3D was developed to generate single and composite grid systems within geometrically complex two- and three-dimensional (2- and 3-D) spatial domains that can deform with time. GRID2D/3D generates single grid systems by using algebraic grid generation methods based on transfinite interpolation in which the distribution of grid points within the spatial domain is controlled by stretching functions. All single grid systems generated by GRID2D/3D can have grid lines that are continuous and differentiable everywhere up to the second-order. Also, grid lines can intersect boundaries of the spatial domain orthogonally. GRID2D/3D generates composite grid systems by patching together two or more single grid systems. The patching can be discontinuous or continuous. For continuous composite grid systems, the grid lines are continuous and differentiable everywhere up to the second-order except at interfaces where different single grid systems meet. At interfaces where different single grid systems meet, the grid lines are only differentiable up to the first-order. For 2-D spatial domains, the boundary curves are described by using either cubic or tension spline interpolation. For 3-D spatial domains, the boundary surfaces are described by using either linear Coon's interpolation, bi-hyperbolic spline interpolation, or a new technique referred to as 3-D bi-directional Hermite interpolation. Since grid systems generated by algebraic methods can have grid lines that overlap one another, GRID2D/3D contains a graphics package for evaluating the grid systems generated. With the graphics package, the user can generate grid systems in an interactive manner with the grid generation part of GRID2D/3D. GRID2D/3D is written in FORTRAN 77 and can be run on any IBM PC, XT, or AT compatible computer. In order to use GRID2D/3D on workstations or mainframe computers, some minor modifications must be made in the graphics part of the program; no

  4. Grid-based Visualization Framework

    Science.gov (United States)

    Thiebaux, M.; Tangmunarunkit, H.; Kesselman, C.

    2003-12-01

    Advances in science and engineering have put high demands on tools for high-performance large-scale visual data exploration and analysis. For example, earthquake scientists can now study earthquake phenomena from first principle physics-based simulations. These simulations can generate large amounts of data, possibly high spatial resolution, and long time series. Single-system visualization software running on commodity machines cannot scale up to the large amounts of data generated by these simulations. To address this problem, we propose a flexible and extensible Grid-based visualization framework for time-critical, interactively controlled visual browsing of spatially and temporally large datasets in a Grid environment. Our framework leverages Grid resources for scalable computation and data storage to maintain performance and interactivity with large visualization jobs. Our framework utilizes Globus Toolkit 2.4 components for security (i.e., GSI), resource allocation and management (i.e., DUROC, GRAM) and communication (i.e., Globus-IO) to couple commodity desktops with remote, scalable storage and computational resources in a Grid for interactive data exploration. There are two major components in this framework---Grid Data Transport (GDT) and the Grid Visualization Utility (GVU). GDT provides libraries for performing parallel data filtering and parallel data exchange among Grid resources. GDT allows arbitrary data filtering to be integrated into the system. It also facilitates multi-tiered pipeline topology construction of compute resources and displays. In addition to scientific visualization applications, GDT can be used to support other applications that require parallel processing and parallel transfer of partial ordered independent files, such as file-set transfer. On top of GDT, we have developed the Grid Visualization Utility (GVU), which is designed to assist visualization dataset management, including file formatting, data transport and automatic

  5. Effects of grid geometry on non-equilibrium dissipation in grid turbulence

    Science.gov (United States)

    Nagata, Koji; Saiki, Teppei; Sakai, Yasuhiko; Ito, Yasumasa; Iwano, Koji

    2017-01-01

    A total of 11 grids in four families, including single- and multi-scale grids, are tested to investigate the development and decay characteristics of grid-generated turbulence. Special attention has been focused on dissipation and non-equilibrium characteristics in the decay region. A wide non-equilibrium region is observed for fractal square grids with three and four iterations. The distributions of the Taylor microscale λ, integral length scale Lu, and dissipation coefficient C ɛ show that a simple combination of large and small grids does not reproduce elongated non-equilibrium regions as realized by the fractal square grid. On the other hand, a new kind of grid, quasi-fractal grids, in which the region of the smaller fractal elements ( N = 2 - 4 ) of the fractal square grid is replaced by regular grids, successfully reproduce a similar flow field and non-equilibrium nature to that seen in the fractal square grid case. This suggests that the combination of large square grid and inhomogeneously arranged smaller grids produces an elongated non-equilibrium region. The dissipation coefficient C ɛ is better collapsed using R e 0 = t 0 U ∞ / ν (where t0 is the thickness of the largest grid bar, U ∞ the inflow velocity, and ν the kinematic viscosity) as a global/inlet Reynolds number rather than R e M = M U ∞ / ν (where M is the mesh size) [P. C. Valente and J. C. Vassilicos, "Universal dissipation scaling for non-equilibrium turbulence," Phys. Rev. Lett. 108, 214503 (2012)].

  6. Smart grid in China

    DEFF Research Database (Denmark)

    Sommer, Simon; Ma, Zheng; Jørgensen, Bo Nørregaard

    2015-01-01

    China is planning to transform its traditional power grid in favour of a smart grid, since it allows a more economically efficient and a more environmentally friendly transmission and distribution of electricity. Thus, a nationwide smart grid is likely to save tremendous amounts of resources...

  7. Switching overvoltages in offshore wind power grids

    DEFF Research Database (Denmark)

    Arana Aristi, Ivan

    Switching transients in wind turbines, the collection grid, the export system and the external grid in offshore wind farms, during normal or abnormal operation, are the most important phenomena when conducting insulation coordination studies. However, the recommended models and methods from...... international standards and guidelines are insufficient to take into account considering the special conditions in offshore wind farms. This thesis focuses on the improvement of models and methods used in specialized electromagnetic transient programs. In this thesis, an introduction to offshore wind farm...... and cables are presented. In Chapter 4 results from time domain measurements and simulations of switching operations in offshore wind power grids are described. Specifically, switching operations on a single wind turbine, the collection grid, the export system and the external grid measured in several real...

  8. A pressure drop model for PWR grids

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Dong Seok; In, Wang Ki; Bang, Je Geon; Jung, Youn Ho; Chun, Tae Hyun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    A pressure drop model for the PWR grids with and without mixing device is proposed at single phase based on the fluid mechanistic approach. Total pressure loss is expressed in additive way for form and frictional losses. The general friction factor correlations and form drag coefficients available in the open literatures are used to the model. As the results, the model shows better predictions than the existing ones for the non-mixing grids, and reasonable agreements with the available experimental data for mixing grids. Therefore it is concluded that the proposed model for pressure drop can provide sufficiently good approximation for grid optimization and design calculation in advanced grid development. 7 refs., 3 figs., 3 tabs. (Author)

  9. Grid Architecture 2

    Energy Technology Data Exchange (ETDEWEB)

    Taft, Jeffrey D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-01-01

    The report describes work done on Grid Architecture under the auspices of the Department of Electricity Office of Electricity Delivery and Reliability in 2015. As described in the first Grid Architecture report, the primary purpose of this work is to provide stakeholder insight about grid issues so as to enable superior decision making on their part. Doing this requires the creation of various work products, including oft-times complex diagrams, analyses, and explanations. This report provides architectural insights into several important grid topics and also describes work done to advance the science of Grid Architecture as well.

  10. Framework for Grid Manufacturing

    Institute of Scientific and Technical Information of China (English)

    陈笠; 邓宏; 邓倩妮; 吴振宇

    2004-01-01

    With the development of networked manufacturing, it is more and more imminent to solve problems caused by inherent limitations of network technology, such as heterogeneity, collaboration collision, and decentralized control.This paper presents a framework for grid manufacturing, which neatly combines grid technology with the infrastructure of advanced manufacturing technology.The paper studies grid-oriented knowledge description and acquisition, and constructs a distributed knowledge grid model.The paper also deals with the protocol of node description in collaborative design, and describes a distributed collaborative design model.The protocol and node technology leads to a collaborative production model for grid manufacturing.The framework for grid manufacturing offers an effective and feasible solution for the problems of networked manufacturing.The grid manufacturing will become an advanced distributed manufacturing model and promote the development of advanced manufacturing technologies.

  11. Securing smart grid technology

    Science.gov (United States)

    Chaitanya Krishna, E.; Kosaleswara Reddy, T.; Reddy, M. YogaTeja; Reddy G. M., Sreerama; Madhusudhan, E.; AlMuhteb, Sulaiman

    2013-03-01

    In the developing countries electrical energy is very important for its all-round improvement by saving thousands of dollars and investing them in other sector for development. For Growing needs of power existing hierarchical, centrally controlled grid of the 20th Century is not sufficient. To produce and utilize effective power supply for industries or people we should have Smarter Electrical grids that address the challenges of the existing power grid. The Smart grid can be considered as a modern electric power grid infrastructure for enhanced efficiency and reliability through automated control, high-power converters, modern communications infrastructure along with modern IT services, sensing and metering technologies, and modern energy management techniques based on the optimization of demand, energy and network availability and so on. The main objective of this paper is to provide a contemporary look at the current state of the art in smart grid communications as well as critical issues on smart grid technologies primarily in terms of information and communication technology (ICT) issues like security, efficiency to communications layer field. In this paper we propose new model for security in Smart Grid Technology that contains Security Module(SM) along with DEM which will enhance security in Grid. It is expected that this paper will provide a better understanding of the technologies, potential advantages and research challenges of the smart grid and provoke interest among the research community to further explore this promising research area.

  12. Smart grid security

    Energy Technology Data Exchange (ETDEWEB)

    Cuellar, Jorge (ed.) [Siemens AG, Muenchen (Germany). Corporate Technology

    2013-11-01

    The engineering, deployment and security of the future smart grid will be an enormous project requiring the consensus of many stakeholders with different views on the security and privacy requirements, not to mention methods and solutions. The fragmentation of research agendas and proposed approaches or solutions for securing the future smart grid becomes apparent observing the results from different projects, standards, committees, etc, in different countries. The different approaches and views of the papers in this collection also witness this fragmentation. This book contains the following papers: 1. IT Security Architecture Approaches for Smart Metering and Smart Grid. 2. Smart Grid Information Exchange - Securing the Smart Grid from the Ground. 3. A Tool Set for the Evaluation of Security and Reliability in Smart Grids. 4. A Holistic View of Security and Privacy Issues in Smart Grids. 5. Hardware Security for Device Authentication in the Smart Grid. 6. Maintaining Privacy in Data Rich Demand Response Applications. 7. Data Protection in a Cloud-Enabled Smart Grid. 8. Formal Analysis of a Privacy-Preserving Billing Protocol. 9. Privacy in Smart Metering Ecosystems. 10. Energy rate at home Leveraging ZigBee to Enable Smart Grid in Residential Environment.

  13. 基于C-MEX建模的全数字单相并网逆变器的研究%Research on all-digital single phase grid connected inverter based on C-MEX modeling

    Institute of Scientific and Technical Information of China (English)

    唐云龙; 杨恢宏; 王若醒; 雷振锋

    2013-01-01

    介绍了一种基于Matlab中C-MEX建模的全数字单相并网逆变器的研制方法。在Matlab环境下由分立器件搭建主电路,由C-MEX进行建模,整机开发手段采用C语言源代码编译,可直接移植入嵌入式开发平台,有效提高开发效率。整机直流侧MPPT 采用扰动观测法,交流侧采用电压外环、电流内环的控制方式,其中亦包含了直流偏磁抑制方法、虚拟单相锁相环以及PR调节等控制方法。最后在该仿真建模的基础上,研制了一台3 kW的单相光伏并网逆变器,将C-MEX中的C源代码移植入DSP嵌入式开发平台,经试验测试,验证了该仿真建模的正确性及该开发模式的优越性。%This paper introduces one kind of method based on the MATLAB C-MEX modeling for all-digital single phase grid connected inverter. The main circuit is built by discrete device, and the module of C-MEX is compiled with the C language source code, which can be transplanted directly into the embedded development platform to improve the development efficiency. The control method of MPPT at DC side is disturbance observation method, and the control method of AC side is based on voltage outer loops and current internal loops, which contains the control methods of DC magnetic bias suppression, virtual single-phase phase-locked loop and the PR regulator. Finally, on the basis of this modeling and simulation, a 3 kW single phase photovoltaic grid-connected inverter is developed, and then the C source code is transplanted into DSP embedded development platform. The test results show the superiority of this development pattern and prove that the simulation model is correct.

  14. MrGrid: a portable grid based molecular replacement pipeline.

    Directory of Open Access Journals (Sweden)

    Jason W Schmidberger

    Full Text Available BACKGROUND: The crystallographic determination of protein structures can be computationally demanding and for difficult cases can benefit from user-friendly interfaces to high-performance computing resources. Molecular replacement (MR is a popular protein crystallographic technique that exploits the structural similarity between proteins that share some sequence similarity. But the need to trial permutations of search models, space group symmetries and other parameters makes MR time- and labour-intensive. However, MR calculations are embarrassingly parallel and thus ideally suited to distributed computing. In order to address this problem we have developed MrGrid, web-based software that allows multiple MR calculations to be executed across a grid of networked computers, allowing high-throughput MR. METHODOLOGY/PRINCIPAL FINDINGS: MrGrid is a portable web based application written in Java/JSP and Ruby, and taking advantage of Apple Xgrid technology. Designed to interface with a user defined Xgrid resource the package manages the distribution of multiple MR runs to the available nodes on the Xgrid. We evaluated MrGrid using 10 different protein test cases on a network of 13 computers, and achieved an average speed up factor of 5.69. CONCLUSIONS: MrGrid enables the user to retrieve and manage the results of tens to hundreds of MR calculations quickly and via a single web interface, as well as broadening the range of strategies that can be attempted. This high-throughput approach allows parameter sweeps to be performed in parallel, improving the chances of MR success.

  15. The turbulent flow generated by inhomogeneous multiscale grids

    Science.gov (United States)

    Zheng, Shaokai; Bruce, Paul J. K.; Graham, J. Michael R.; Vassilicos, John Christos

    2015-11-01

    A group of inhomogeneous multiscale grids have been designed and tested in a low speed wind tunnel in an attempt to generate bespoke turbulent shear flows. Cross-wire anemometry measurements were performed in different planes parallel to the grid and at various streamwise locations to study turbulence development behind each of the different geometry grids. Two spatially separated single hot wires were also used to measure transverse integral length scale at selected locations. Results are compared to previous studies of shearless mixing layer grids and fractal grids, including mean flow profiles and turbulence statistics.

  16. Evaluation of the Sustaining Effects of Tai Chi Qigong in the Sixth Month in Promoting Psychosocial Health in COPD Patients: A Single-Blind, Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Aileen W. K. Chan

    2013-01-01

    Full Text Available Objectives. To evaluate the sustaining effects of Tai Chi Qigong (TCQ in improving the psychosocial health in chronic obstructive pulmonary disease (COPD patients in the sixth month. Background. COPD affects both physical and emotional aspects of life. Measures to minimize patients' suffering need to be implemented. Methods. 206 COPD patients were randomly assigned into three groups: TCQ group, exercise group, and control group. The TCQ group completed a three-month TCQ program, the exercise group practiced breathing and walking exercise, and the control group received usual care. Results. Significant group-by-time interactions in quality of life (QOL using St. George's respiratory questionnaire (P = 0.002 and the perceived social support from friends using multidimensional scale of perceived social support (P = 0.04 were noted. Improvements were observed in the TCQ group only. Conclusions. TCQ has sustaining effects in improving psychosocial health; it is also a useful and appropriate exercise for COPD patients.

  17. Immediate loading of bimaxillary total fixed prostheses supported by five flapless-placed implants with machined surfaces: A 6-month follow-up prospective single cohort study.

    Science.gov (United States)

    Cannizzaro, Gioacchino; Felice, Pietro; Loi, Ignazio; Viola, Paolo; Ferri, Vittorio; Leone, Michele; Collivasone, Dario; Esposito, Marco

    2016-01-01

    To evaluate the clinical outcome of fully edentulous patients rehabilitated with immediately loaded bimaxillary screw-retained metal-resin prostheses supported by five implants placed flapless: two in the mandible and three in the maxillae. Twenty-five consecutively treated patients were recruited. To be immediately loaded, implants had to be inserted with a minimum torque of 80 Ncm. Outcome measures were prosthesis and implant failures, and complications. Six months after loading no patients dropped out and no prosthesis or implant failed. Two maxillary prostheses were loaded early at 8 weeks because implants were inserted with a torque inferior to 45 Ncm. Three complications occurred in two patients but they were all successfully treated. Six months after loading, immediately loaded bimaxillary cross-arch prostheses can be supported by only two mandibular and three maxillary flapless-placed dental implants. Longer follow-ups of approximately 10 years are needed to understand the prognosis of this treatment modality.

  18. The Grid : english version

    CERN Multimedia

    Rosy Mondardini Producer

    2003-01-01

    The Grid : . Sharing resources owned by many different organizations to access remote computers, software, and data efficiently and automatically . Secure access to establish the identity of a user or resource, after defining conditions under which sharing occurs . Bridging distance using high-speed connections between computers to create a global Grid . Open standards to allow applications designed for one Grid to run on all others

  19. A randomised comparison of single-incision versus traditional transobturator midurethral sling in women with stress urinary incontinence : results of a 24-month follow-up

    NARCIS (Netherlands)

    Schellart, René P; Rengerink, Katrien Oude; Van der Aa, Frank; Lucot, Jean-Philippe; Kimpe, Bart; Dijkgraaf, Marcel G W; Roovers, Jan-Paul W R

    2015-01-01

    INTRODUCTION AND HYPOTHESIS: Midurethral sling procedures have become the principal surgical treatment for women with stress urinary incontinence (SUI). The 1-year results of this international trial comparing the efficacy and morbidity of a single-incision midurethral sling (SIMS; MiniArc) and a tr

  20. GRID Activities in ALICE

    Institute of Scientific and Technical Information of China (English)

    P.Cerello; T.Anticic; 等

    2001-01-01

    The challenge of LHC computing,with data rates in the range of several PB/year,requires the development of GRID technologies,to optimize the exploitation of distributed computing power and the authomatic access to distributed data storage.In the framework of the EU-DataGrid project,the ALICE experiment is one of the selected test applications for the early development and implementation of GRID Services.Presently,about 15 ALICE sites are makin use of available GRID tools and a large scale test production involving 9 of them was carried out with our simulation program.Results are discussed in detail,as well as future plans.

  1. Challenges facing production grids

    Energy Technology Data Exchange (ETDEWEB)

    Pordes, Ruth; /Fermilab

    2007-06-01

    Today's global communities of users expect quality of service from distributed Grid systems equivalent to that their local data centers. This must be coupled to ubiquitous access to the ensemble of processing and storage resources across multiple Grid infrastructures. We are still facing significant challenges in meeting these expectations, especially in the underlying security, a sustainable and successful economic model, and smoothing the boundaries between administrative and technical domains. Using the Open Science Grid as an example, I examine the status and challenges of Grids operating in production today.

  2. The play grid

    DEFF Research Database (Denmark)

    Fogh, Rune; Johansen, Asger

    2013-01-01

    In this paper we propose The Play Grid, a model for systemizing different play types. The approach is psychological by nature and the actual Play Grid is based, therefore, on two pairs of fundamental and widely acknowledged distinguishing characteristics of the ego, namely: extraversion vs...... at the Play Grid. Thus, the model has four quadrants, each of them describing one of four play types: the Assembler, the Director, the Explorer, and the Improviser. It is our hope that the Play Grid can be a useful design tool for making entertainment products for children....

  3. 光伏并网逆变器中的单相数字锁相环研究%The Research of Single-phase PLL in the Photovoltaic Grid-connected Inverter System

    Institute of Scientific and Technical Information of China (English)

    金曼; 苏建徽

    2011-01-01

    在光伏并网系统中,准确并快速地检测到电网电压的频率、相位和幅值是必不可少的环节.传统数字锁相环检测电网电压的过零点从而实现锁相,但该方法抗干扰能力差.基于二阶通用积分器的单相锁相环较传统的数字锁相环具有不受电网频率变化影响、抗干扰能力强的优点,但该算法在离散化实现时会引入二次谐波而导致锁相准确度降低.这里在基于二阶通用积分器的单相锁相环方法上进行改进,利用陷波器滤除二次谐波,该方法适用于工程应用,同时提出了一种新的陷波器数字实现方法.最后进行了实验验证,结果表明该方法不受电网频率变化的影响,能迅速准确地锁相并消除了二次谐波污染.%Accurate and rapid detection of frequency, phase and amplitude of the grid voltage is essential in the gridconnected system. Traditional digital PLL obtains the frequency and phase by detecting the zero-crossing point, but this method is very sensitive to noise. Comparing to traditional digital PLL, single-phase PLL based on second-order generalized integrator has the advantages that the results are not affected by the frequency changes and insenstive to noise.However, the realization of the algorithm will draw into second harmonic pollution which reduces the accuracy of the phase-lock.The single-phase PLL based on second-order generalized integrator method is improved by using the notch filter to filtered second harmonic, this method is suitable for engineering applications, and meanwhile a new digital relization method of notch filter is proposed.The experiments are taken and proposed.The results show that the proposed method is not affected by the grid frequency changes,the phase and frequency information can be obtained quickly and accurately, and does not produce second harmonic pollution.

  4. GLA MONTHLY GRIDS from NOAA-10 V001

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset contains the TIROS Operational Vertical Sounder (TOVS) level 3 geophysical parameters derived using the physical retrieval method of Susskind et al....

  5. Dynamic Resource Allocation in Desktop Grids

    Directory of Open Access Journals (Sweden)

    Bismi A S,

    2010-08-01

    Full Text Available Grid computing (or the use of computational grids is the application of several computers to a single problem at the same time. In grid computing ,the computing becomes pervasive and individual users(or client applicationgain access to computing resources (processors ,storage ,data,applications,and so onas needed with little or noknowledge of where those resources are located or what the underlying technologies, hardware ,operating system and so on. This paper address the problem of resource scheduling ,and there are so many resource scheduling algorithms .Resource scheduling algorithm may be centralized one and distributed one. One of the latest one is the multi-variable best fit algorithm, which deals with storage systems, and it enhanced in this work. and this algorithm is dealing withdata grids for blade servers. so, this algorithm is modified for computational grids, especially with desktop systems with minimum spanning algorithm for node selection and it is giving good results. In desktop grid environment, dynamic scheduling becomes very important and globus like toolkits are not having the scheduler as its own, and it needs other schedulers are not specially for computational grids.

  6. The CMS integration grid testbed

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Gregory E.

    2004-08-26

    The CMS Integration Grid Testbed (IGT) comprises USCMS Tier-1 and Tier-2 hardware at the following sites: the California Institute of Technology, Fermi National Accelerator Laboratory, the University of California at San Diego, and the University of Florida at Gainesville. The IGT runs jobs using the Globus Toolkit with a DAGMan and Condor-G front end. The virtual organization (VO) is managed using VO management scripts from the European Data Grid (EDG). Gridwide monitoring is accomplished using local tools such as Ganglia interfaced into the Globus Metadata Directory Service (MDS) and the agent based Mona Lisa. Domain specific software is packaged and installed using the Distribution After Release (DAR) tool of CMS, while middleware under the auspices of the Virtual Data Toolkit (VDT) is distributed using Pacman. During a continuous two month span in Fall of 2002, over 1 million official CMS GEANT based Monte Carlo events were generated and returned to CERN for analysis while being demonstrated at SC2002. In this paper, we describe the process that led to one of the world's first continuously available, functioning grids.

  7. Study on Novel Single-phase Photovoltaic Grid-connected Inverter with Three Switching Devices%一种新型单相三开关光伏并网逆变器研究

    Institute of Scientific and Technical Information of China (English)

    章勇高; 李洋; 康淦明; 常凯旋

    2014-01-01

    光伏逆变器由于受外界因素以及逆变器的一些内在因素的影响,导致逆变器对输入电压的要求很严格。传统的逆变器加变压器的方法和多级级联的方法不能够妥善解决输入电压适应性的问题。为满足对大范围直流电压输入变化的适应性要求,同时实现光伏并网逆变器逆变与升压两个功能,提出了一种新型的单相三开关光伏并网逆变器拓扑。采用高频开关器件和反激变换器,替换了传统笨重的工频升压变压器,使得逆变器的体积、重量及成本降低,易于集成,且提高了变换效率。实时波形反馈技术的闭环SPWM(sinusoidal pulse width modulation)控制方法,可提供快速响应。通过一个小的交流滤波器可获得低谐波失真的正弦输出。对理论分析结果进行仿真验证,结果表明该新型单相三开关光伏并网逆变器具有拓扑简单,适应大范围直流输入电压变化,可靠性高等优点。%There are strict requirements of input voltage for a photovoltaic inverter due to some external effects and internal factors, and it is difficult to solve the problem of tolerance to varied input DC voltage properly through the traditional method of an inverter plus a transformer and multi-stage cascading. In order to meet the need of tole-rance to a widely varied input DC voltage and realize the function of inversion and step-up in photovoltaic grid-connected inverter, this paper puts forward a novel single-phase photovoltaic grid-connected inverter topology with three switches. High-frequency switches and fly-back converter were adopted to substitute the traditional bulky line frequency step-up transformer, which made the system easy to integrate with small volume, low weight and cost, and higher efficiency. The closed-loop sinusoidal PWM control method with real-time waveform feed-back technique can provide fast dynamic response. Through a small ac filter, the inverter

  8. GridOrbit public display

    DEFF Research Database (Denmark)

    Ramos, Juan David Hincapie; Tabard, Aurélien; Bardram, Jakob

    2010-01-01

    We introduce GridOrbit, a public awareness display that visualizes the activity of a community grid used in a biology laboratory. This community grid executes bioin-formatics algorithms and relies on users to donate CPU cycles to the grid. The goal of GridOrbit is to create a shared awareness about...

  9. The LHCb Grid Simulation

    CERN Multimedia

    Baranov, Alexander

    2016-01-01

    The LHCb Grid access if based on the LHCbDirac system. It provides access to data and computational resources to researchers with different geographical locations. The Grid has a hierarchical topology with multiple sites distributed over the world. The sites differ from each other by their number of CPUs, amount of disk storage and connection bandwidth. These parameters are essential for the Grid work. Moreover, job scheduling and data distribution strategy have a great impact on the grid performance. However, it is hard to choose an appropriate algorithm and strategies as they need a lot of time to be tested on the real grid. In this study, we describe the LHCb Grid simulator. The simulator reproduces the LHCb Grid structure with its sites and their number of CPUs, amount of disk storage and bandwidth connection. We demonstrate how well the simulator reproduces the grid work, show its advantages and limitations. We show how well the simulator reproduces job scheduling and network anomalies, consider methods ...

  10. Security for grids

    Energy Technology Data Exchange (ETDEWEB)

    Humphrey, Marty; Thompson, Mary R.; Jackson, Keith R.

    2005-08-14

    Securing a Grid environment presents a distinctive set of challenges. This paper groups the activities that need to be secured into four categories: naming and authentication; secure communication; trust, policy, and authorization; and enforcement of access control. It examines the current state of the art in securing these processes and introduces new technologies that promise to meet the security requirements of Grids more completely.

  11. DataGrid

    CERN Multimedia

    Silvano de Gennaro

    2003-01-01

    DataGrid is a project funded by the European Union that aims to enable access to geographically distributed computing power and storage facilities belonging to different institutions. This will provide scientists with an unprecedented computing and data management tool. DataGrid is led by CERN, together with 20 other scientific and industrial partners.

  12. CPR, ECLS, BVAD and successful heart transplantation within 2 months: a single-centre case series in two young, high-urgency listed patients.

    Science.gov (United States)

    Schmidt, Anna K; Saeed, Diyar; Mehdiani, Arash; Sowinski, Bozena; Westenfeld, Ralf; Akhyari, Payam; Lichtenberg, Artur; Boeken, Udo

    2017-07-20

    In times of organ shortage, death while on the heart waiting-list still represents a major problem. As a consequence, bridging to transplant as well as the decision when to escalate therapy play a very important role. We report on two young patients with dilated cardiomyopathy and acute decompensation who were successfully bridged to heart transplantation with both left and temporary right ventricular assist devices in just 2 months. As a permanent biventricular assist device (BVAD) would have definitely impaired the patients' outcome after HTX, we decided to implant an LVAD with a temporary RVAD. In our opinion, this represents a suitable strategy to reduce mortality in HU-listed patients with acute deterioration of cardiac pump function and should be further evaluated in future studies.

  13. Sirolimus-eluting stents for treatment of drug-eluting versus bare-metal stents restenosis: 42-month clinical outcomes from a Chinese single center

    Institute of Scientific and Technical Information of China (English)

    YAN Rong-qiang; LIU Hai-bo; WU Yong-jian; YUAN Jin-qing; CHEN Jue; YOU Shi-jie; DAI Jun; GAO Run-lin; CHEN Ji-lin; GAO Li-jian; YANG Yue-jin; LI Jian-jun; QIAO Shu-bin; XU Bo; YAO Min; QIN Xue-wen

    2012-01-01

    Background Restenosis of bare-metal stents (BMS) and drug-eluting stents (DES) has been increasingly treated with sirolimus-eluting stents (SES),but the long-term outcomes are unknown.Methods In our study,388 consecutive patients (144 DES restenosis and 244 BMS restenosis) with 400 lesions (147 DES restenosis and 253 BMS restenosis) treated with SES were included.The rates of target lesion revascularization (TLR) and major adverse cardiac events (MACE) at 42 months were analyzed.Results At the mean follow-up of 42 months,the rates of death (3.5% vs.3.3%,P=1.000) and myocardial infarction (2.8% vs.1.2%,P=0.431) in the DES group and BMS group were comparable.Compared with the BMS group,ischemia-driven TLR occurred with a higher frequency in the DES group (18.8% vs.10.7%,P=0.024).This translated into an increased rate of MACE in the DES group (22.2% vs.14.0%,P=0.034).Stent thrombosis occurred with a similar frequency in both groups (2.8% vs.1.6%,P=0.475).Multivariate analysis showed that DES restenosis (OR=1.907,95%Cl 1.108-3.285,P=0.020) and smoking (OR=2.069; 95% C/ 1.188-3.605; P=0.010) were independent predictors of MACE.Conclusions Although SES implantation appears to be safe and effective,it was associated with higher TLR recurrence for DES than BMS restenosis.

  14. Percutaneous left atrial appendage occlusion – treatment outcomes and 6 months of follow-up – a single-center experience

    Science.gov (United States)

    Karczewski, Michał; Skowronek, Radomir; Burysz, Marian; Fischer, Marcin; Anisimowicz, Lech; Demkow, Marcin; Konka, Marek; Ogorzeja, Wojciech

    2016-01-01

    Aim To present the results of treatment and evaluate 6 months of follow-up in a group of patients with non-valvular atrial fibrillation, who underwent the procedure of percutaneous left atrial appendage occlusion (PLAAO). Material and methods Percutaneous left atrial appendage occlusion was performed in 34 patients with non-valvular atrial fibrillation and contraindications for oral anticoagulation therapy. The risk of thromboembolic and bleeding complications was determined based on the CHA2DS2VASc and HAS-BLED scales. The Amplatzer Amulet system from St. Jude Medical was used. On the first postoperative day, all patients were started on double antiplatelet therapy with 75 mg/day of acetylsalicylic acid (ASA) and 75 mg/day of clopidogrel (CLO). On the 30th postoperative day, the efficacy of the antiplatelet therapy was assessed with impedance aggregometry using a Multiplate analyzer (Roche). Echocardiographic examinations were performed intraoperatively and on the first postoperative day; subsequently, follow-up examinations were conducted 1 and 6 months after the implantation. Results In all patients, proper occluder position was observed throughout the follow-up. No leakage or thrombi around the implants were found. No strokes or bleeding complications associated with the antiplatelet therapy were observed. Multiplate assessment of platelet activity was conducted in 20 out of 34 patients. The efficacy of ASA treatment was demonstrated in all patients; no response to clopidogrel treatment was observed in 5 out of 20 patients. One patient suffered from cardiac tamponade, which required the performance of full sternotomy. Local complications (hematomas of the inguinal region) were observed in 3 patients. One of the patients died for reasons unrelated to the procedure. Conclusions Percutaneous left atrial appendage occlusion is an effective procedure in patients with non-valvular atrial fibrillation and contraindications for chronic anticoagulation therapy. Further

  15. QOS based user driven scheduler for grid environment

    CERN Document Server

    Patel, Sanjay

    2011-01-01

    As grids are in essence heterogeneous, dynamic, shared and distributed environments, managing these kinds of platforms efficiently is extremely complex. A promising scalable approach to deal with these intricacies is the design of self-managing of autonomic applications. Autonomic applications adapt their execution accordingly by considering knowledge about their own behaviour and environmental conditions.QoS based User Driven scheduling for grid that provides the self-optimizing ability in autonomic applications. Computational grids to provide a user to solve large scale problem by spreading a single large computation across multiple machines of physical location. QoS based User Driven scheduler for grid also provides reliability of the grid systems and increase the performance of the grid to reducing the execution time of job by applying scheduling policies defined by the user. The main aim of this paper is to distribute the computational load among the available grid nodes and to developed a QoS based sche...

  16. Data Grid Implementations

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Reagan W.; Studham, Ronald S.; Rajasekar, Arcot; Watson, Chip; Stockinger, Heinz; Kunszt, Peter; Charlie Catlett and Ian Foster

    2002-02-27

    Data grids link distributed, heterogeneous storage resources into a coherent data management system. From a user perspective, the data grid provides a uniform name space across the underlying storage systems, while supporting retrieval and storage of files. In the high energy physics community, at least six data grids have been implemented for the storage and distribution of experimental data. Data grids are also being used to support projects as diverse as digital libraries (National Library of Medicine Visible Embryo project), federation of multiple astronomy sky surveys (NSF National Virtual Observatory project), and integration of distributed data sets (Long Term Ecological Reserve). Data grids also form the core interoperability mechanisms for creating persistent archives, in which data collections are migrated to new technologies over time. The ability to provide a uniform name space across multiple administration domains is becoming a critical component of national-scale, collaborative projects.

  17. Grid generation methods

    CERN Document Server

    Liseikin, Vladimir D

    2017-01-01

    This new edition provides a description of current developments relating to grid methods, grid codes, and their applications to actual problems. Grid generation methods are indispensable for the numerical solution of differential equations. Adaptive grid-mapping techniques, in particular, are the main focus and represent a promising tool to deal with systems with singularities. This 3rd edition includes three new chapters on numerical implementations (10), control of grid properties (11), and applications to mechanical, fluid, and plasma related problems (13). Also the other chapters have been updated including new topics, such as curvatures of discrete surfaces (3). Concise descriptions of hybrid mesh generation, drag and sweeping methods, parallel algorithms for mesh generation have been included too. This new edition addresses a broad range of readers: students, researchers, and practitioners in applied mathematics, mechanics, engineering, physics and other areas of applications.

  18. Smart grid in China

    DEFF Research Database (Denmark)

    Sommer, Simon; Ma, Zheng; Jørgensen, Bo Nørregaard

    2015-01-01

    China is planning to transform its traditional power grid in favour of a smart grid, since it allows a more economically efficient and a more environmentally friendly transmission and distribution of electricity. Thus, a nationwide smart grid is likely to save tremendous amounts of resources...... and costs. This paper elaborates on the key stakeholders, crucial polices and general challenges in the context of the Chinese smart grid development. The paper finds that the Chinese energy market is a state monopoly and foreign companies can only become key stakeholders in the role of suppliers or service...... providers. It can be concluded that the Chinese smart grid development has still to overcome technological and political issues, such as overlapping authority structures, not installed or immature key technologies, the absence of standards and governmental market protectionism....

  19. National Smart Water Grid

    Energy Technology Data Exchange (ETDEWEB)

    Beaulieu, R A

    2009-07-13

    crossing the US-Mexico border; and decreased eutrophication (excessive plant growth and decay) in the Gulf of Mexico to name a few. The National Smart Water Grid{trademark} will pay for itself in a single major flood event.

  20. Constructing a Grid Simulation for E-Governance Applications Using GridSim

    Directory of Open Access Journals (Sweden)

    Mrs. P. Sumathi

    2008-01-01

    Full Text Available This study provides a design framework for the adoption of grid computing for e-governance applications. Problem statement: E-Governance is the application of information and communication technology to achieve efficiency, effectiveness, transparency and accountability in Government to Government (G2G, Government to Employee (G2E, Government to Citizen (G2C and Government to Business (G2B. It enables citizens to make best use of automated administration processes that are accessible on-line. Grid computing is an ideal solution to this type of applications and the study presents how grid computing can be used to effectively and efficiently handle such huge data. In this study, we illustrate the creation of a virtual environment by using existing Grid technologies to specific e-governance applications on distributed resources. Approach: A Grid generally refers to an infrastructure that involves the integrated and collaborative use of all computing resources into a single virtual computing environment. Grid applications often involve large amounts of data and/or computing resources that require secure resource sharing across organizational boundaries. Grid computing is an ideal solution to this type of applications and the study presents how grid computing can be used to effectively and efficiently handle such huge data. Results: The applications were run with the grid environment and without Grid environment. The results obtained were compared with the time and the number of jobs. The obtained results using grid environment were more significant and promising. Conclusions: Implementing an E-Governance solution will lower the cost of developing, deploying, managing government solutions and providing better services to citizens.

  1. BSCW Unstructured Grids - VGRID software

    Data.gov (United States)

    National Aeronautics and Space Administration — These grids were constructed using VGRID software from NASA Langley. The grids designed for node based (labeled 'nc') and cell-centered solvers are supplied. Grids...

  2. HIRENASD Unstructured Grids - VGRID software

    Data.gov (United States)

    National Aeronautics and Space Administration — These grids were constructed using VGRID software from NASA Langley. The grids designed for node based (labeled 'nc') and cell-centered solvers are supplied. Grids...

  3. Initial results of local grid control using wind farms with grid support

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Poul; Hansen, Anca D.; Iov, F.; Blaabjerg, F.

    2005-09-01

    This report describes initial results with simulation of local grid control using wind farms with grid support. The focus is on simulation of the behaviour of the wind farms when they are isolated from the main grid and establish a local grid together with a few other grid components. The isolated subsystems used in the work presented in this report do not intend to simulate a specific subsystem, but they are extremely simplified single bus bar systems using only a few more components than the wind farm. This approach has been applied to make it easier to understand the dynamics of the subsystem. The main observation is that the fast dynamics of the wind turbines seem to be able to contribute significantly to the grid control, which can be useful where the wind farm is isolated with a subsystem from the main grid with surplus of generation. Thus, the fast down regulation of the wind farm using automatic frequency control can keep the subsystem in operation and thereby improve the reliability of the grid. (LN)

  4. Decentral Smart Grid Control

    Science.gov (United States)

    Schäfer, Benjamin; Matthiae, Moritz; Timme, Marc; Witthaut, Dirk

    2015-01-01

    Stable operation of complex flow and transportation networks requires balanced supply and demand. For the operation of electric power grids—due to their increasing fraction of renewable energy sources—a pressing challenge is to fit the fluctuations in decentralized supply to the distributed and temporally varying demands. To achieve this goal, common smart grid concepts suggest to collect consumer demand data, centrally evaluate them given current supply and send price information back to customers for them to decide about usage. Besides restrictions regarding cyber security, privacy protection and large required investments, it remains unclear how such central smart grid options guarantee overall stability. Here we propose a Decentral Smart Grid Control, where the price is directly linked to the local grid frequency at each customer. The grid frequency provides all necessary information about the current power balance such that it is sufficient to match supply and demand without the need for a centralized IT infrastructure. We analyze the performance and the dynamical stability of the power grid with such a control system. Our results suggest that the proposed Decentral Smart Grid Control is feasible independent of effective measurement delays, if frequencies are averaged over sufficiently large time intervals.

  5. Comparison of control strategies for Doubly fed induction generator under recurring grid faults

    DEFF Research Database (Denmark)

    Chen, Wenjie; Blaabjerg, Frede; Zhu, Nan;

    2014-01-01

    The new grid codes demand the wind turbine systems to ride through recurring grid faults. Many control strategies have been proposed for the Doubly Fed Induction Generator under single grid fault, but their performance under recurring grid faults have not been studied yet. In this paper, five...... different control strategies for DFIG to ride through single grid faults are presented, and their performance under recurring grid faults are analyzed. The controllable range, stator time constant and torque fluctuations of the DFIG with different control strategies are compared. The results are verified...

  6. Grid today, clouds on the horizon

    Science.gov (United States)

    Shiers, Jamie

    2009-04-01

    By the time of CCP 2008, the largest scientific machine in the world - the Large Hadron Collider - had been cooled down as scheduled to its operational temperature of below 2 degrees Kelvin and injection tests were starting. Collisions of proton beams at 5+5 TeV were expected within one to two months of the initial tests, with data taking at design energy ( 7+7 TeV) foreseen for 2009. In order to process the data from this world machine, we have put our "Higgs in one basket" - that of Grid computing [The Worldwide LHC Computing Grid (WLCG), in: Proceedings of the Conference on Computational Physics 2006 (CCP 2006), vol. 177, 2007, pp. 219-223]. After many years of preparation, 2008 saw a final "Common Computing Readiness Challenge" (CCRC'08) - aimed at demonstrating full readiness for 2008 data taking, processing and analysis. By definition, this relied on a world-wide production Grid infrastructure. But change - as always - is on the horizon. The current funding model for Grids - which in Europe has been through 3 generations of EGEE projects, together with related projects in other parts of the world, including South America - is evolving towards a long-term, sustainable e-infrastructure, like the European Grid Initiative (EGI) [The European Grid Initiative Design Study, website at http://web.eu-egi.eu/]. At the same time, potentially new paradigms, such as that of "Cloud Computing" are emerging. This paper summarizes the results of CCRC'08 and discusses the potential impact of future Grid funding on both regional and international application communities. It contrasts Grid and Cloud computing models from both technical and sociological points of view. Finally, it discusses the requirements from production application communities, in terms of stability and continuity in the medium to long term.

  7. Transmission grid security

    CERN Document Server

    Haarla, Liisa; Hirvonen, Ritva; Labeau, Pierre-Etienne

    2011-01-01

    In response to the growing importance of power system security and reliability, ""Transmission Grid Security"" proposes a systematic and probabilistic approach for transmission grid security analysis. The analysis presented uses probabilistic safety assessment (PSA) and takes into account the power system dynamics after severe faults. In the method shown in this book the power system states (stable, not stable, system breakdown, etc.) are connected with the substation reliability model. In this way it is possible to: estimate the system-wide consequences of grid faults; identify a chain of eve

  8. Instant 960 Grid System

    CERN Document Server

    Tres, Diego

    2013-01-01

    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. Instant 960 Grid System uses step-by-step instructions, covering the basic understanding needed to create a quick, high quality responsive website prototype using the 960 Grid System.The book is intended for beginner web developers and information architects looking to create a quick responsive website prototype. Basic knowledge of web development and a little understanding of grids is encouraged.

  9. Desktop grid computing

    CERN Document Server

    Cerin, Christophe

    2012-01-01

    Desktop Grid Computing presents common techniques used in numerous models, algorithms, and tools developed during the last decade to implement desktop grid computing. These techniques enable the solution of many important sub-problems for middleware design, including scheduling, data management, security, load balancing, result certification, and fault tolerance. The book's first part covers the initial ideas and basic concepts of desktop grid computing. The second part explores challenging current and future problems. Each chapter presents the sub-problems, discusses theoretical and practical

  10. GridAPPS-D

    Energy Technology Data Exchange (ETDEWEB)

    2017-03-28

    GridAPPS-D is an open-source, open architecture, standards based platform for development of advanced electric power system planning and operations applications. GridAPPS-D provides a documented data abstraction for the application developer enabling creation of applications that can be run in any compliant system or platform. This enables development of applications that are platform vendor independent applications and applications that take advantage of the possibility of data rich and data driven applications based on deployment of smart grid devices and systems.

  11. Phase-lock loop of Grid-connected Voltage Source Converter under non-ideal grid condition

    DEFF Research Database (Denmark)

    Wang, Haojie; Sun, Hai; Han, Minxiao

    2015-01-01

    phase information cannot be accurately tracked. Based on analysis of the cause of double-frequency ripple when unbalance exists in main grid, a phase-locked loop (PLL) detection technique is proposed. Under the conditions of unsymmetrical system voltage, varying system frequency, single-phase system...... and distorted system voltage the proposed PLL can accurately detect the fundamental positive-sequence component of grid voltage thus accurate control of DC micro-grid voltage can be realized....

  12. RSW Cell Centered Grids

    Data.gov (United States)

    National Aeronautics and Space Administration — New cell centered grids are generated to complement the node-centered ones uploaded. Six tarballs containing the coarse, medium, and fine mixed-element and pure tet....

  13. Grid Computing Education Support

    Energy Technology Data Exchange (ETDEWEB)

    Steven Crumb

    2008-01-15

    The GGF Student Scholar program enabled GGF the opportunity to bring over sixty qualified graduate and under-graduate students with interests in grid technologies to its three annual events over the three-year program.

  14. Technology Roadmaps: Smart Grids

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    The development of Technology Roadmaps: Smart Grids -- which the IEA defines as an electricity network that uses digital and other advanced technologies to monitor and manage the transport of electricity from all generation sources to meet the varying electricity demands of end users -- is essential if the global community is to achieve shared goals for energy security, economic development and climate change mitigation. Unfortunately, existing misunderstandings of exactly what smart grids are and the physical and institutional complexity of electricity systems make it difficult to implement smart grids on the scale that is needed. This roadmap sets out specific steps needed over the coming years to achieve milestones that will allow smart grids to deliver a clean energy future.

  15. Lincoln Laboratory Grid

    Data.gov (United States)

    Federal Laboratory Consortium — The Lincoln Laboratory Grid (LLGrid) is an interactive, on-demand parallel computing system that uses a large computing cluster to enable Laboratory researchers to...

  16. Controlling smart grid adaptivity

    NARCIS (Netherlands)

    Toersche, Hermen; Nykamp, Stefan; Molderink, Albert; Hurink, Johann L.; Smit, Gerardus Johannes Maria

    2012-01-01

    Methods are discussed for planning oriented smart grid control to cope with scenarios with limited predictability, supporting an increasing penetration of stochastic renewable resources. The performance of these methods is evaluated with simulations using measured wind generation and consumption

  17. Scheduling for Responsive Grids

    CERN Document Server

    Germain-Renaud, C; Moscicki,JT; Texier, R

    2008-01-01

    Grids are facing the challenge of seamless integration of the Grid power into everyday use. One critical component for this integration is responsiveness, the capacity to support on-demand computing and interactivity. Grid scheduling is involved at two levels in order to provide responsiveness: the policy level and the implementation level. The main contributions of this paper are as follows. First, we present a detailed analysis of the performance of the EGEE Grid with respect to responsiveness. Second, we examine two user-level schedulers located between the general scheduling layer and the application layer. These are the DIANE (distributed analysis environment) framework, a general-purpose overlay system, and a specialized, embedded scheduler for gPTM3D, an interactive medical image analysis application. Finally, we define and demonstrate a virtualization scheme, which achieves guaranteed turnaround time, schedulability analysis, and provides the basis for differentiated services. Both methods target a br...

  18. World Wide Grid

    CERN Multimedia

    Grätzel von Grätz, Philipp

    2007-01-01

    Whether for genetic risk analysis or 3D-rekonstruktion of the cerebral vessels: the modern medicine requires more computing power. With a grid infrastructure, this one can be if necessary called by the network. (4 pages)

  19. US National Grid

    Data.gov (United States)

    Kansas Data Access and Support Center — This is a polygon feature data layer of United States National Grid (1000m x 1000m polygons ) constructed by the Center for Interdisciplinary Geospatial Information...

  20. Cascading failures in ac electricity grids

    Science.gov (United States)

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

    2016-09-01

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

  1. International Lattice Data Grid

    CERN Document Server

    Davies, C T H; Kenway, R D; Maynard, C M

    2002-01-01

    We propose the co-ordination of lattice QCD grid developments in different countries to allow transparent exchange of gauge configurations in future, should participants wish to do so. We describe briefly UKQCD's XML schema for labelling and cataloguing the data. A meeting to further develop these ideas will be held in Edinburgh on 19/20 December 2002, and will be available over AccessGrid.

  2. 基于反激拓扑的高效率太阳能微型单级并网逆变器%High efficiency solar energy single-stage grid-connected micro-inverter based on flyback topology

    Institute of Scientific and Technical Information of China (English)

    潘铭航; 苏秀蓉; 王正仕

    2013-01-01

    针对使用中央逆变器及组串式逆变器的光伏发电系统中整体太阳能转换效率不高的缺点,提出了将单个太阳能电池板连接一个小功率的逆变器以组成光伏系统,该系统能够使每个太阳能电池板都工作于最大功率点,针对该系统设计了基于反激拓扑的高效率单级并网逆变器,通过电流峰值控制,将太阳能电池板发出的直流电变换成与电网电压幅值匹配的正弦馒头波,再通过工作于工频状态下的晶闸管桥臂换相成正弦交流电,并人电网,锁相采用过零点检测法,最大功率点跟踪(MPPT)算法采用扰动法,给出了控制框图,并搭建了100 W的实验样机.研究结果表明,基于反激拓扑的单级并网逆变器与单个太阳能电池板组成的光伏系统可以有效地提高整个光伏发电系统的太阳能转换效率.%Aiming at raising the efficiency of the whole photovoltaic (PV) generating system, a low-power inverter was introduced to individually mount on each photovoltaic module to form a system. In this system, each PV module can work at the maximum power point. A micro-inverter based on flyback topology using single-stage grid-connected method was proposed for this system. The flyback was controlled to convert the direct current produced by the PV panel into a rectified sine wave through the peak current control,and then a SCR bridge was used to unfold the rectified sine wave to an alternative one. The zero detecting method was used to do the phase lock logic,the perturbation method was used to do the maximum power point tracking(MPPT)of the PV panel and the control block was given. At last,a 100 W prototype was presented. The experiment results show that the flyback based single-staged grid-connected system raises the efficiency of the whole PV generating system.

  3. Functional and anatomical results after a single intravitreal Ozurdex injection in retinal vein occlusion: a 6-month follow-up -- the SOLO study.

    Science.gov (United States)

    Bezatis, Athanasios; Spital, Georg; Höhn, Fabian; Maier, Mathias; Clemens, Christoph R; Wachtlin, Joachim; Lehmann, Florian; Hattenbach, Lars Olof; Feltgen, Nicolas; Meyer, Carsten H

    2013-08-01

    To evaluate the efficacy of intravitreal dexamethasone implants in eyes with cystoid macular oedema (CME) secondary to branch retinal vein occlusion (BRVO) or central retinal vein occlusion (CRVO) in the clinical everyday practice, examine the effects of early retreatment and compare the results with the GENEVA study. The charts of 102 patients (102 eyes) with CME secondary to BRVO (n = 54) or CRVO (n = 48) treated with Ozurdex at 8 centres were retrospectively reviewed. The patients were examined monthly over a 24-week period. Slit-lamp biomicroscopy, measurement of best-corrected visual acuity (BCVA) and measurement of the central retinal thickness (CRT) with spectral-domain optical coherence tomography (SD-OCT) were performed at baseline and at every follow-up examination. With progression of the disease (loss of one line or increased central retinal thickness (CRT) of 150 μm), a reinjection of Ozurdex or anti-VEGF was offered. Additional supplementing sectorial or panretinal laser photocoagulation was considered based on the individual status of the retina. In the BRVO group, the median BCVA was 0.6 logMAR (Snellen equivalent of 0.25) at baseline and improved to 0.4 logMAR (Snellen equivalent of 0.40) after 4 weeks, 0.3 logMAR (Snellen equivalent of 0.50) after 8 weeks, 0.4 logMAR (Snellen equivalent of 0.40) after 12 weeks, 0.5 logMAR (Snellen equivalent of 0.32) after 16 weeks, 0.4 logMAR (Snellen equivalent of 0.40) after 20 weeks and 0.45 logMAR (Snellen equivalent of 0.35) after 24 weeks. The mean CRT was 559 ± (SD) 209 μm at baseline and it decreased to 335 ± 148 μm after 4 weeks, 316 ± 137 μm after 8 weeks, 369 ± 126 μm after 12 weeks, 407 ± 161 μm after 16 weeks, 399 ± 191 μm after 20 weeks and 419 ± 196 μm after 24 weeks. In the CRVO group, the median BCVA was 0.7 logMAR (Snellen equivalent of 0.20) at baseline and improved to 0.4 logMAR (Snellen equivalent of 0.40) after 4 weeks, 0.4 logMAR (Snellen equivalent of 0.40) after 8 weeks, 0

  4. RRS: Replica Registration Service for Data Grids

    Energy Technology Data Exchange (ETDEWEB)

    Shoshani, Arie; Sim, Alex; Stockinger, Kurt

    2005-07-15

    Over the last few years various scientific experiments and Grid projects have developed different catalogs for keeping track of their data files. Some projects use specialized file catalogs, others use distributed replica catalogs to reference files at different locations. Due to this diversity of catalogs, it is very hard to manage files across Grid projects, or to replace one catalog with another. In this paper we introduce a new Grid service called the Replica Registration Service (RRS). It can be thought of as an abstraction of the concepts for registering files and their replicas. In addition to traditional single file registration operations, the RRS supports collective file registration requests and keeps persistent registration queues. This approach is of particular importance for large-scale usage where thousands of files are copied and registered. Moreover, the RRS supports a set of error directives that are triggered in case of registration failures. Our goal is to provide a single uniform interface for various file catalogs to support the registration of files across multiple Grid projects, and to make Grid clients oblivious to the specific catalog used.

  5. Arc Length Based Grid Distribution For Surface and Volume Grids

    Science.gov (United States)

    Mastin, C. Wayne

    1996-01-01

    Techniques are presented for distributing grid points on parametric surfaces and in volumes according to a specified distribution of arc length. Interpolation techniques are introduced which permit a given distribution of grid points on the edges of a three-dimensional grid block to be propagated through the surface and volume grids. Examples demonstrate how these methods can be used to improve the quality of grids generated by transfinite interpolation.

  6. Arc length based grid distribution for surface and volume grids

    Energy Technology Data Exchange (ETDEWEB)

    Mastin, C.W. [NASA Langley Research Center, Hampton, VA (United States)

    1996-12-31

    Techniques are presented for distributing grid points on parametric surfaces and in volumes according to a specified distribution of arc length. Interpolation techniques are introduced which permit a given distribution of grid points on the edges of a three-dimensional grid block to be propagated through the surface and volume grids. Examples demonstrate how these methods can be used to improve the quality of grids generated by transfinite interpolation.

  7. GPM, GMI Level 3 Monthly GPROF Profiling VV03B

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  8. GPM, GMI Level 3 Monthly GPROF Profiling VV03C

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  9. GPM, GMI Level 3 Monthly GPROF Profiling VV03A

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  10. GRID2D/3D: A computer program for generating grid systems in complex-shaped two- and three-dimensional spatial domains. Part 2: User's manual and program listing

    Science.gov (United States)

    Bailey, R. T.; Shih, T. I.-P.; Nguyen, H. L.; Roelke, R. J.

    1990-01-01

    An efficient computer program, called GRID2D/3D, was developed to generate single and composite grid systems within geometrically complex two- and three-dimensional (2- and 3-D) spatial domains that can deform with time. GRID2D/3D generates single grid systems by using algebraic grid generation methods based on transfinite interpolation in which the distribution of grid points within the spatial domain is controlled by stretching functions. All single grid systems generated by GRID2D/3D can have grid lines that are continuous and differentiable everywhere up to the second-order. Also, grid lines can intersect boundaries of the spatial domain orthogonally. GRID2D/3D generates composite grid systems by patching together two or more single grid systems. The patching can be discontinuous or continuous. For continuous composite grid systems, the grid lines are continuous and differentiable everywhere up to the second-order except at interfaces where different single grid systems meet. At interfaces where different single grid systems meet, the grid lines are only differentiable up to the first-order. For 2-D spatial domains, the boundary curves are described by using either cubic or tension spline interpolation. For 3-D spatial domains, the boundary surfaces are described by using either linear Coon's interpolation, bi-hyperbolic spline interpolation, or a new technique referred to as 3-D bi-directional Hermite interpolation. Since grid systems generated by algebraic methods can have grid lines that overlap one another, GRID2D/3D contains a graphics package for evaluating the grid systems generated. With the graphics package, the user can generate grid systems in an interactive manner with the grid generation part of GRID2D/3D. GRID2D/3D is written in FORTRAN 77 and can be run on any IBM PC, XT, or AT compatible computer. In order to use GRID2D/3D on workstations or mainframe computers, some minor modifications must be made in the graphics part of the program; no

  11. Smart Grid Integration Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Troxell, Wade [Colorado State Univ., Fort Collins, CO (United States)

    2011-12-22

    The initial federal funding for the Colorado State University Smart Grid Integration Laboratory is through a Congressionally Directed Project (CDP), DE-OE0000070 Smart Grid Integration Laboratory. The original program requested in three one-year increments for staff acquisition, curriculum development, and instrumentation all which will benefit the Laboratory. This report focuses on the initial phase of staff acquisition which was directed and administered by DOE NETL/ West Virginia under Project Officer Tom George. Using this CDP funding, we have developed the leadership and intellectual capacity for the SGIC. This was accomplished by investing (hiring) a core team of Smart Grid Systems engineering faculty focused on education, research, and innovation of a secure and smart grid infrastructure. The Smart Grid Integration Laboratory will be housed with the separately funded Integrid Laboratory as part of CSU's overall Smart Grid Integration Center (SGIC). The period of performance of this grant was 10/1/2009 to 9/30/2011 which included one no cost extension due to time delays in faculty hiring. The Smart Grid Integration Laboratory's focus is to build foundations to help graduate and undergraduates acquire systems engineering knowledge; conduct innovative research; and team externally with grid smart organizations. Using the results of the separately funded Smart Grid Workforce Education Workshop (May 2009) sponsored by the City of Fort Collins, Northern Colorado Clean Energy Cluster, Colorado State University Continuing Education, Spirae, and Siemens has been used to guide the hiring of faculty, program curriculum and education plan. This project develops faculty leaders with the intellectual capacity to inspire its students to become leaders that substantially contribute to the development and maintenance of Smart Grid infrastructure through topics such as: (1) Distributed energy systems modeling and control; (2) Energy and power conversion; (3

  12. Prosumers and smart grid technologies in Denmark: developing user competences in smart grid households

    DEFF Research Database (Denmark)

    Hansen, Meiken; Hauge, Bettina

    2017-01-01

    This paper explores and describes resident’s experiences from a smart grid project that involved 20 households in a rural area in Denmark and ran from 2014 to 2015. The study is based on qualitative data from the participating households, collected 6, 12 and 18 months after the start of the inter......This paper explores and describes resident’s experiences from a smart grid project that involved 20 households in a rural area in Denmark and ran from 2014 to 2015. The study is based on qualitative data from the participating households, collected 6, 12 and 18 months after the start...... of the intervention. Drawing on theories of social practice and the three intertwined elements of a practice: competences, images and materials, the paper contributes with an in-depth analysis of a complex intervention, focusing on how the participants changed energy practices as a result of the installed smart grid...

  13. The Control Mode of Distribution Grid/Off-Grid of Wind-Solar-Storage with Double Boost-Buck Converter Single Inverter Based on V2 Control Method%基于V2控制方法双Boost-Buck单一逆变器的风光储分布并网/孤岛离网控制模式

    Institute of Scientific and Technical Information of China (English)

    希望·阿不都瓦依提; 晁勤; 王筱

    2016-01-01

    目前边缘农牧区采用风光互补发电,由于通过各自逆变器运行,存在成本高、能耗高等问题。提出采用双Boost-Buck单一逆变器结构实现风光储联合发电共用直流母线方案,达到降低投资成本和运行能耗的效果。首先设计了基于 V2控制双 Boost-Buck 变换器风光储联合发电的拓扑结构和电路,实现了输入电压在较宽范围内波动时输出电压仍然能够恒值控制的目标,同时采用电压斜坡补偿方法抑制了Boost-Buck电路自激振荡问题。接着基于蓄电池,制定了储能平抑风光波动、九宫分区跟随负荷、模糊充放电等控制策略,达到了风光储发电与逆变器无缝对接。其次基于风光储联合发电系统,进行了减小弃风光电量效益评估。最后基于风光储分布并网和孤岛离网控制模式,研发了软硬件装置,进行了仿真验证和试验测试。结果表明:逆变器输出电流具有良好的静、动态性能,同时实现了较好的经济性、有效性、稳定性和可靠性。%Wind and solar hybrid power generation is widely used in agricultural and pastoral areas. In current applications, each system uses independent inverters, which requires higher cost and energy consumption. In this paper, a common DC bus scheme with dual Boost-Buck based single inverter structure was proposed, to realize wind and solar hybrid power generation. The proposed scheme can reduce cost and energy consumption. Firstly, topological structure and circuit of wind-solar-storage cogeneration system were designed based on V2 controlled double Boost-Buck converter. Hence the constant voltage value control can be achieved when the input voltage varies in a wide range. At the same time, voltage slope compensation method was used to suppress the self-excited oscillation of Boost-Buck circuit. Secondly, a series of control strategies were designed to improve storage stability, including stabilizing

  14. Security Considerations Based on PKI/CA in Manufacturing Grid

    Institute of Scientific and Technical Information of China (English)

    YIN Yong; LI Yu

    2006-01-01

    In the manufacturing grid environment, the span of the consideration of security issues is more extensive, and the solutions for them are more complex, therefore these problems in manufacturing grid can't longer be addressed by existing security technologies. In order to solve this problem, the paper first puts forward the security architecture of manufacturing grid on the basis of the proposal of the security strategies for manufacturing grid; then the paper introduces key technologies based on public key infrastructure-certificate authority (PKI/CA) to ensure the security of manufacturing grid, such as single sign-on, security proxy, independent authentication and so on. Schemes discussed in the paper have some values to settle security problems in the manufacturing grid environment.

  15. Inter-Operating Grids Through Delegated MatchMaking

    Directory of Open Access Journals (Sweden)

    Alexandru Iosup

    2008-01-01

    Full Text Available The grid vision of a single computing utility has yet to materialize: while many grids with thousands of processors each exist, most work in isolation. An important obstacle for the effective and efficient inter-operation of grids is the problem of resource selection. In this paper we propose a solution to this problem that combines the hierarchical and decentralized approaches for interconnecting grids. In our solution, a hierarchy of grid sites is augmented with peer-to-peer connections between sites under the same administrative control. To operate this architecture, we employ the key concept of delegated matchmaking, which temporarily binds resources from remote sites to the local environment. With trace-based simulations we evaluate our solution under various infrastructural and load conditions, and we show that it outperforms other approaches to inter-operating grids. Specifically, we show that delegated matchmaking achieves up to 60% more goodput and completes 26% more jobs than its best alternative.

  16. The Grid is operational – it’s official!

    CERN Multimedia

    2008-01-01

    On Friday, 3 October, CERN and its many partners around the world officially marked the end of seven years of development and deployment of the Worldwide LHC Computing Grid (WLCG) and the beginning of continuous operations with an all-day Grid Fest. Wolfgang von Rüden unveils the WLCG sculpture. Les Robertson speaking at the Grid Fest. At the LHC Grid Fest, Bob Jones highlights the far-reaching uses of grid computing. Over 250 grid-enthusiasts gathered in the Globe, including large delegations from the press and from industrial partners, as well as many of the people around the world who manage the distributed operations of the WLCG, which today comprises more than 140 computer centres in 33 countries. As befits a cutting-edge information technology, many participants joined virtually, by video, to mark the occasion. Unlike the start-up of the LHC, there was no single moment of high dram...

  17. Integration of complex reservoir grids for hydromechanical coupling

    Science.gov (United States)

    Nakaten, Benjamin; Pohl, Maik; Kempka, Thomas

    2017-04-01

    Geomechanics became an integral part in the assessment of geological subsurface utilization during the last decade. However, complex grids as applied in state-of-the-art reservoir simulation, including local grid refinements, pinch-out elements resulting from geological discontinuities and reservoirs of low thickness, hinder a straight-forward integration of these grids into geomechanical simulations. Hence, the geomechanical modelling community tends to simplify their grid discretization schemes to meet the grid geometry criteria required by geomechanical simulators or to apply complex interpolation methods between reservoir simulation and geomechanical grids. Both approaches are known to result in significant deviations compared to coupled simulations conducted on the very same grid. Hereby, the application of specific interpolation methods further demands for careful result verification between single parameter transfers between both simulation grids, e.g., including the development of model-specific verification procedures. Consequently, utilization of identical grids in both simulators should be preferred over both workarounds. Resolving this pressing issue, we implemented a fast algorithm using FLAC3D [1] intrinsics (C++), allowing for an efficient and seamless integration of Schlumberger ECLIPSE grids [2], generated using, e.g., the Petrel software package [3], including pinch-out elements and local grid refinements (LGRs). This algorithm comprises four major steps: (1) read the ECLIPSE global grid (hexahedron and pinch-out elements) and generate a compressed corner point grid with unique element nodes; (2) read any LGRs present in the model and transfer these to the geomechanical grid using the previously retrieved global grid information; (3) verify if all (including pinch-outs) element geometries meet the geomechanical grid geometry criteria and revise these elements as required; (4) parametrize the global grid and LGR elements and maintain a data

  18. QoS Based User Driven Scheduler for Grid Environment

    Directory of Open Access Journals (Sweden)

    Sanjay Patel

    2011-05-01

    Full Text Available As grids are in essence heterogeneous, dynamic, shared and distributed environments, managing thesekinds of platforms efficiently is extremely complex. A promising scalable approach to deal with theseintricacies is the design of self-managing of autonomic applications. Autonomic applications adapt theirexecution accordingly by considering knowledge about their own behaviour and environmentalconditions.QoS based User Driven scheduling for grid that provides the self-optimizing ability inautonomic applications. Computational grids to provide a user to solve large scale problem by spreadinga single large computation across multiple machines of physical location.QoS based User Driven scheduler for grid also provides reliability of the grid systems and increase theperformance of the grid to reducing the execution time of job by applying scheduling policies defined bythe user. The main aim of this paper is to distribute the computational load among the available gridnodes and to developed a QoS based scheduling algorithm for grid and making grid more reliable.Gridcomputing system is different from conventional distributed computing systems by its focus on large scaleresource sharing, where processors and communication have significant inuence on Grid computingreliability. Reliability capabilities initiated by end users from within applications they submit to the gridfor execution. Reliability of infrastructure and management services that perform essential functionsnecessary for grid systems to operate, such as resource allocation and scheduling.

  19. Turbulent mixing of a passive scalar in grid turbulence

    Science.gov (United States)

    Ito, Y.; Watanabe, T.; Nagata, K.; Sakai, Y.

    2016-07-01

    Fractal grids have attracted attention as a new-type of turbulence-generating grid due to their unique characteristics. Recent studies have revealed that such uniqueness appears in the near field of regular grid-generated turbulence. Scalar transport in those flows is also of great interest as it is not yet fully understood. In this study, we investigate the scalar mixing in the near field of regular grid-generated turbulence with various grid configurations. Experiments have been carried out in liquid mixing layers with a Reynolds number of 5000 based on the mesh size of the grid and uniform velocity. Simultaneous measurements of two-component velocities and concentration have been performed by particle image velocimetry and a planar laser-induced fluorescence technique, respectively. The results show that the scaling law using the wake-interaction length scale is applicable for the turbulence intensity in the grid turbulence with different mesh sizes and the same thickness of the grid bar. The turbulence intensity increases as the thickness of the grid bar increases; thus, consequently increasing the scalar diffusion. The streamwise development of the scalar mixing layer thickness collapses onto a single curve by normalization based on the thickness of the grid bar.

  20. SMART GRIDS LABORATORIES INVENTORY 2015

    OpenAIRE

    PONCELA BLANCO MARTA; PRETTICO GIUSEPPE; ANDREADOU NIKOLETA; OLARIAGA-GUARDIOLA Miguel; FULLI Gianluca; COVRIG CATALIN-FELIX

    2015-01-01

    A smart electricity grid opens the door to a myriad of new applications aimed at enhancing security of supply, sustainability and market competitiveness. Gathering detailed information about smart grid laboratories activities represents a primary need. In order to obtain a better picture of the ongoing Smart Grid developments, after the successful smart grid project survey initiated in 2011, we recently launched a focused on-line survey addressed to organisations owning or running Smart Grid ...

  1. Grid Data Management and Customer Demands at MeteoSwiss

    Science.gov (United States)

    Rigo, G.; Lukasczyk, Ch.

    2010-09-01

    Data grids constitute the required input form for a variety of applications. Therefore, customers increasingly expect climate services to not only provide measured data, but also grids of these with the required configurations on an operational basis. Currently, MeteoSwiss is establishing a production chain for delivering data grids by subscription directly from the data warehouse in order to meet the demand for precipitation data grids by governmental, business and science customers. The MeteoSwiss data warehouse runs on an Oracle database linked with an ArcGIS Standard edition geodatabase. The grids are produced by Unix-based software written in R called GRIDMCH which extracts the station data from the data warehouse and stores the files in the file system. By scripts, the netcdf-v4 files are imported via an FME interface into the database. Currently daily and monthly deliveries of daily precipitation grids are available from MeteoSwiss with a spatial resolution of 2.2km x 2.2km. These daily delivered grids are a preliminary based on 100 measuring sites whilst the grid of the monthly delivery of daily sums is calculated out of about 430 stations. Crucial for the absorption by the customers is the understanding of and the trust into the new grid product. Clearly stating needs which can be covered by grid products, the customers require a certain lead time to develop applications making use of the particular grid. Therefore, early contacts and a continuous attendance as well as flexibility in adjusting the production process to fulfill emerging customer needs are important during the introduction period. Gridding over complex terrain can lead to temporally elevated uncertainties in certain areas depending on the weather situation and coverage of measurements. Therefore, careful instructions on the quality and use and the possibility to communicate the uncertainties of gridded data proofed to be essential especially to the business and science customers who require

  2. Prosumers and smart grid technologies in Denmark: developing user competences in smart grid households

    DEFF Research Database (Denmark)

    Hansen, Meiken; Hauge, Bettina

    2017-01-01

    This paper explores and describes resident’s experiences from a smart grid project that involved 20 households in a rural area in Denmark and ran from 2014 to 2015. The study is based on qualitative data from the participating households, collected 6, 12 and 18 months after the start of the inter...

  3. Improved DFIG Capability during Asymmetrical Grid Faults

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede

    2015-01-01

    , the capability of a 2 MW DFIG to ride through asymmetrical grid faults can be estimated at the existing design of the power electronics converter. Finally, a control scheme aimed to improve the DFIG capability is proposed and the simulation results validate its feasibility.......In the wind power application, different asymmetrical types of the grid fault can be categorized after the Y/d transformer, and the positive and negative components of a single-phase fault, phase-to-phase fault, and two-phase fault can be summarized. Due to the newly introduced negative and even...

  4. Lightweight Grid Shell Pavilion - Design, Manufacture and Erection of Full Scale Grid Shell Prototypes

    Science.gov (United States)

    Vaněk, Aleš

    2016-12-01

    The main goal of author's research is to design and construct grid shell structures, which are subsequently realized as experimental structures in full scale. These structures should make the place suitable for various events and also a friendly, pleasant, relaxing and free time space. By thinking about how such structure should look like and what materials and structure types are suitable, there were many kinds of lightweight structures considered. The most logical solution is to create a grid shell structure combining with a single layer membrane that would fulfill all aspects of elegant remarkable lightweight structure using some original details and workflow advancements. These grid shell projects should demonstrate another possibility to build and think about unconventional structures and provoke a deeper interest in these unique structures. The goal of this project was to create a feasible design of a grid shell structure and to build up the structures while being capable to understand the core of such an interesting phenomenon.

  5. Grid and Entrepreneurship Workshop

    CERN Multimedia

    2006-01-01

    The CERN openlab is organising a special workshop about Grid opportunities for entrepreneurship. This one-day event will provide an overview of what is involved in spin-off technology, with a special reference to the context of computing and data Grids. Lectures by experienced entrepreneurs will introduce the key concepts of entrepreneurship and review, in particular, the industrial potential of EGEE (the EU co-funded Enabling Grids for E-sciencE project, led by CERN). Case studies will be given by CEOs of European start-ups already active in the Grid and computing cluster area, and regional experts will provide an overview of efforts in several European regions to stimulate entrepreneurship. This workshop is designed to encourage students and researchers involved or interested in Grid technology to consider the entrepreneurial opportunities that this technology may create in the coming years. This workshop is organized as part of the CERN openlab student programme, which is co-sponsored by CERN, HP, ...

  6. The CMS Integration Grid Testbed

    CERN Document Server

    Graham, G E; Aziz, Shafqat; Bauerdick, L.A.T.; Ernst, Michael; Kaiser, Joseph; Ratnikova, Natalia; Wenzel, Hans; Wu, Yu-jun; Aslakson, Erik; Bunn, Julian; Iqbal, Saima; Legrand, Iosif; Newman, Harvey; Singh, Suresh; Steenberg, Conrad; Branson, James; Fisk, Ian; Letts, James; Arbree, Adam; Avery, Paul; Bourilkov, Dimitri; Cavanaugh, Richard; Rodriguez, Jorge Luis; Kategari, Suchindra; Couvares, Peter; DeSmet, Alan; Livny, Miron; Roy, Alain; Tannenbaum, Todd; Graham, Gregory E.; Aziz, Shafqat; Ernst, Michael; Kaiser, Joseph; Ratnikova, Natalia; Wenzel, Hans; Wu, Yujun; Aslakson, Erik; Bunn, Julian; Iqbal, Saima; Legrand, Iosif; Newman, Harvey; Singh, Suresh; Steenberg, Conrad; Branson, James; Fisk, Ian; Letts, James; Arbree, Adam; Avery, Paul; Bourilkov, Dimitri; Cavanaugh, Richard; Rodriguez, Jorge; Kategari, Suchindra; Couvares, Peter; Smet, Alan De; Livny, Miron; Roy, Alain; Tannenbaum, Todd

    2003-01-01

    The CMS Integration Grid Testbed (IGT) comprises USCMS Tier-1 and Tier-2 hardware at the following sites: the California Institute of Technology, Fermi National Accelerator Laboratory, the University of California at San Diego, and the University of Florida at Gainesville. The IGT runs jobs using the Globus Toolkit with a DAGMan and Condor-G front end. The virtual organization (VO) is managed using VO management scripts from the European Data Grid (EDG). Gridwide monitoring is accomplished using local tools such as Ganglia interfaced into the Globus Metadata Directory Service (MDS) and the agent based Mona Lisa. Domain specific software is packaged and installed using the Distrib ution After Release (DAR) tool of CMS, while middleware under the auspices of the Virtual Data Toolkit (VDT) is distributed using Pacman. During a continuo us two month span in Fall of 2002, over 1 million official CMS GEANT based Monte Carlo events were generated and returned to CERN for analysis while being demonstrated at SC2002. ...

  7. 基于TMS320F28027的单相光伏并网系统设计%The Design of a Single-phase Grid-connected PV System Based on TMS320F28027

    Institute of Scientific and Technical Information of China (English)

    陈立功

    2011-01-01

    According to the characteristics of grid-connected photovoltaic system, the paper presents the design of a photovoltaic grid-connected inverter based on the digital signal processor TMS320F28027, and analyzes the formation and control principle of the system. The output waveforms of inverter and DSP output waveform are tested. The experimental results show the grid-connected current wave meets the need. The wave of grid-connected current has the same frequency and phase as the utility voltage. The grid-connected power factor approaches 1.%根据光伏并网发电系统的特点,设计了一套基于数字信号处理器TMS320F28027控制的单相光伏并网逆变器,分析了系统的结构和控制原理,并对系统的逆变输出和DSP输出SPWM波形进行测试.实验结果表明,并网电流波形良好,逆变器输出的电流基本与电网电压同频同相,并网的功率因数近似为1.

  8. Space-based Science Operations Grid Prototype

    Science.gov (United States)

    Bradford, Robert N.; Welch, Clara L.; Redman, Sandra

    2004-01-01

    Grid technology is the up and coming technology that is enabling widely disparate services to be offered to users that is very economical, easy to use and not available on a wide basis. Under the Grid concept disparate organizations generally defined as "virtual organizations" can share services i.e. sharing discipline specific computer applications, required to accomplish the specific scientific and engineering organizational goals and objectives. Grids are emerging as the new technology of the future. Grid technology has been enabled by the evolution of increasingly high speed networking. Without the evolution of high speed networking Grid technology would not have emerged. NASA/Marshall Space Flight Center's (MSFC) Flight Projects Directorate, Ground Systems Department is developing a Space-based Science Operations Grid prototype to provide to scientists and engineers the tools necessary to operate space-based science payloads/experiments and for scientists to conduct public and educational outreach. In addition Grid technology can provide new services not currently available to users. These services include mission voice and video, application sharing, telemetry management and display, payload and experiment commanding, data mining, high order data processing, discipline specific application sharing and data storage, all from a single grid portal. The Prototype will provide most of these services in a first step demonstration of integrated Grid and space-based science operations technologies. It will initially be based on the International Space Station science operational services located at the Payload Operations Integration Center at MSFC, but can be applied to many NASA projects including free flying satellites and future projects. The Prototype will use the Internet2 Abilene Research and Education Network that is currently a 10 Gb backbone network to reach the University of Alabama at Huntsville and several other, as yet unidentified, Space Station based

  9. Smart Grid Architectures

    DEFF Research Database (Denmark)

    Dondossola, Giovanna; Terruggia, Roberta; Bessler, Sandford

    2014-01-01

    The scope of this paper is to address the evolution of distribution grid architectures following the widespread introduction of renewable energy sources. The increasing connection of distributed resources has a strong impact on the topology and the control functionality of the current distribution...... grids requiring the development of new Information and Communication Technology (ICT) solutions with various degrees of adaptation of the monitoring, communication and control technologies. The costs of ICT based solutions need however to be taken into account, hence it is desirable to work...... with existing communication networks. The objective of the European FP7 project SmartC2Net in this regard is to enable robust smart grid control utilizing heterogeneous third party communication infrastructures....

  10. The Computing Grids

    Energy Technology Data Exchange (ETDEWEB)

    Govoni, P. [Universita and INFN Milano-Bicocca (Italy)

    2009-12-15

    Since the beginning of the millennium, High Energy Physics research institutions like CERN and INFN pioneered several projects aimed at exploiting the synergy among computing power, storage and network resources, and creating an infrastructure of distributed computing on a worldwide scale. In the year 2000, after the Monarch project [(http://monarc.web.cern.ch/MONARC/)], DataGrid started [(http://eu-datagrid.web.cern.ch/eu-datagrid/)] aimed at providing High Energy Physics with the computing power needed for the LHC enterprise. This program evolved into the EU DataGrid project, that implemented the first actual prototype of a Grid middleware running on a testbed environment. The next step consisted in the application to the LHC experiments, with the LCG project [(http://lcg.web.cern.ch/LCG/)], in turn followed by the EGEE [(http://www.eu-egee.org/)] and EGEE II programs.

  11. Fusion Data Grid Service

    Science.gov (United States)

    Shasharina, Svetlana; Wang, Nanbor

    2004-11-01

    Simulations and experiments in the fusion and plasma physics community generate large datasets at remote sites. Visualization and analysis of these datasets are difficult because of the incompatibility among the various data formats adopted by simulation, experiments, and analysis tools, and the large sizes of analyzed data. Grids and Web Services technologies are capable of providing solutions for such heterogeneous settings, but need to be customized to the field-specific needs and merged with distributed technologies currently used by the community. This paper describes how we are addressing these issues in the Fusion Grid Service under development. We also present performance results of relevant data transfer mechanisms including binary SOAP, DIME, GridFTP and MDSplus and CORBA. We will describe the status of data converters (between HDF5 and MDSplus data types), developed in collaboration with MIT (J. Stillerman). Finally, we will analyze bottlenecks of MDSplus data transfer mechanism (work performed in collaboration with General Atomics (D. Schissel and M. Qian).

  12. GridOrbit public display

    DEFF Research Database (Denmark)

    Ramos, Juan David Hincapie; Tabard, Aurélien; Bardram, Jakob

    2010-01-01

    We introduce GridOrbit, a public awareness display that visualizes the activity of a community grid used in a biology laboratory. This community grid executes bioin-formatics algorithms and relies on users to donate CPU cycles to the grid. The goal of GridOrbit is to create a shared awareness about...... the research taking place in the biology laboratory. This should promote contribu-tions to the grid, and thereby mediate the appropriation of the grid technology. GridOrbit visualizes the activity in the grid, shows information about the different active projects, and supports a messaging functionality where...... people comment on projects. Our work explores the usage of interactive technologies as enablers for the appropriation of an otherwise invisible infrastructure....

  13. Distributed photovoltaic grid transformers

    CERN Document Server

    Shertukde, Hemchandra Madhusudan

    2014-01-01

    The demand for alternative energy sources fuels the need for electric power and controls engineers to possess a practical understanding of transformers suitable for solar energy. Meeting that need, Distributed Photovoltaic Grid Transformers begins by explaining the basic theory behind transformers in the solar power arena, and then progresses to describe the development, manufacture, and sale of distributed photovoltaic (PV) grid transformers, which help boost the electric DC voltage (generally at 30 volts) harnessed by a PV panel to a higher level (generally at 115 volts or higher) once it is

  14. Smart Grid Architectures

    DEFF Research Database (Denmark)

    Dondossola, Giovanna; Terruggia, Roberta; Bessler, Sandford

    2014-01-01

    grids requiring the development of new Information and Communication Technology (ICT) solutions with various degrees of adaptation of the monitoring, communication and control technologies. The costs of ICT based solutions need however to be taken into account, hence it is desirable to work......The scope of this paper is to address the evolution of distribution grid architectures following the widespread introduction of renewable energy sources. The increasing connection of distributed resources has a strong impact on the topology and the control functionality of the current distribution...

  15. Viewpoints on Grid Standards

    Institute of Scientific and Technical Information of China (English)

    Andrew A. Chien; Xian-He Sun; Zhi-Wei Xu

    2005-01-01

    @@ At GCC 2003 in Shanghai in December 2003, a panel discussion was held on the future of grid computing and on the role of the Globus Toolkit in future grid standards. Panelists include Andrew Chien (UCSD, USA), Wolfgang Gentzsch (Sun),Francis Lau (HKU, China), Carl Kesselman (USC, USA), Satoshi Matsuoka (TIT, Japan), Xian-He Sun (IIT, USA), Richard Wirt (Intel), Liang-Jie Zhang (IBM Research), Song-Nian Zhou (Platform Computing), and Zhi-Wei Xu (ICT, China), with Hai Jin (HUST, China) served as the coordinator. The panel talks were stimulating and well received. Three of the panel talk notes are selected and included in this viewpoint.

  16. Instant jqGrid

    CERN Document Server

    Manricks, Gabriel

    2013-01-01

    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. A step-by-step, practical Starter book, Instant jqGrid embraces you while you take your first steps, and introduces you to the content in an easy-to-follow order.This book is aimed at people who have some knowledge of HTML and JavaScript. Knowledge of PHP and SQL would also prove to be beneficial. No prior knowledge of jqGrid is expected.

  17. Grids, Clouds and Virtualization

    CERN Document Server

    Cafaro, Massimo

    2011-01-01

    Research into grid computing has been driven by the need to solve large-scale, increasingly complex problems for scientific applications. Yet the applications of grid computing for business and casual users did not begin to emerge until the development of the concept of cloud computing, fueled by advances in virtualization techniques, coupled with the increased availability of ever-greater Internet bandwidth. The appeal of this new paradigm is mainly based on its simplicity, and the affordable price for seamless access to both computational and storage resources. This timely text/reference int

  18. 可调度型单相光伏并网逆变器控制策略研究%Study of control strategy for dispatchable PV grid-connected single-phase inverter

    Institute of Scientific and Technical Information of China (English)

    王雪; 张建成

    2012-01-01

    为实现中小容量单相光伏发电系统灵活、可控运行,弥补现有控制方法在有功功率调度方面存在的灵活性差、误差较大的问题,提出了一种基于输出电流控制的新型双闭环控制策略.首先进行外环控制器的寻优,然后对采用不同调制方式的电流滞环控制与新型双环控制策略进行对比分析.利用Matlab/Simulink软件构建了基于各种方案的并网逆变系统模型并进行仿真分析.结果表明,所提出的控制策略在有功功率调度方面具备显著优势,输出电流总谐波畸变率小,功率可调度范围宽,具有广阔的工程应用前景.%Aiming at realizing the flexible and controllable operation of small and medium-sized capacity single-phase photovoltaic (PV) system and solving the problems of traditional control methods such as inflexibility and error defect, a novel double-loop control strategy based on output current control is proposed. The first step of the research is optimization of outer loop controller. Then, a contrast between hysteresis current control with different modulation modes and the method raised in the paper is made. Grid-connected inverter simulated module is built with Matlab/Simulink software. Simulation results show the proposed control strategy has significant advantages in active power dispatching, namely, the total harmonic distortion rate of output current is smaller, and the active power dispatching range is wider. As a result, this method has a broad engineering application prospect.

  19. Discovery Mondays: 'The Grid: a universal computer'

    CERN Multimedia

    2006-01-01

    How can one store and analyse the 15 million billion pieces of data that the LHC will produce each year with a computer that isn't the size of a sky-scraper? The IT experts have found the answer: the Grid, which will harness the power of tens of thousands of computers in the world by putting them together on one network and making them work like a single computer achieving a power that has not yet been matched. The Grid, inspired from the Web, already exists - in fact, several of them exist in the field of science. The European EGEE project, led by CERN, contributes not only to the study of particle physics but to medical research as well, notably in the study of malaria and avian flu. The next Discovery Monday invites you to explore this futuristic computing technology. The 'Grid Masters' of CERN have prepared lively animations to help you understand how the Grid works. Children can practice saving the planet on the Grid video game. You will also discover other applications such as UNOSAT, a United Nations...

  20. Grid computing the European Data Grid Project

    CERN Document Server

    Segal, B; Gagliardi, F; Carminati, F

    2000-01-01

    The goal of this project is the development of a novel environment to support globally distributed scientific exploration involving multi- PetaByte datasets. The project will devise and develop middleware solutions and testbeds capable of scaling to handle many PetaBytes of distributed data, tens of thousands of resources (processors, disks, etc.), and thousands of simultaneous users. The scale of the problem and the distribution of the resources and user community preclude straightforward replication of the data at different sites, while the aim of providing a general purpose application environment precludes distributing the data using static policies. We will construct this environment by combining and extending newly emerging "Grid" technologies to manage large distributed datasets in addition to computational elements. A consequence of this project will be the emergence of fundamental new modes of scientific exploration, as access to fundamental scientific data is no longer constrained to the producer of...

  1. GRID super scalar: from the Grid to the Cell processor

    Energy Technology Data Exchange (ETDEWEB)

    Badia, R. M.; Bellerns, P.; Palol, M. de; Ejarque, J.; Labarta, J.; Perez, J. M.; Sirvent, R.; Tejedor, E.

    2007-07-01

    GRID superscalar is a Grid programming environment that allows to easily program applications that will be efficiently run on a computational Grid. Is able to parallelise, at runtime and at task level, a sequential application and execute it in the Grid. The used approach is able to take benefit from those applications that are composed of coarse grained tasks. These tasks can be the size of a simulation, a program, a solver... These kinds of applications are very common in bioinformatics, computational chemistry and other scientific fields. From the very initial prototype in Condor, GRID superscalar has evolved in a robust framework based in Globus and other middlewares. The effort of the GRID superscalar project goes beyond the Grid computing field, tackling now the newest field of programming multi-core chip's platforms. This paper describes the currently available versions of GRID superscalar. (Author)

  2. Managing Uncertainty: A Case for Probabilistic Grid Scheduling

    CERN Document Server

    Lazarevic, Aleksandar; Prnjat, Ognjen

    2007-01-01

    The Grid technology is evolving into a global, service-orientated architecture, a universal platform for delivering future high demand computational services. Strong adoption of the Grid and the utility computing concept is leading to an increasing number of Grid installations running a wide range of applications of different size and complexity. In this paper we address the problem of elivering deadline/economy based scheduling in a heterogeneous application environment using statistical properties of job historical executions and its associated meta-data. This approach is motivated by a study of six-month computational load generated by Grid applications in a multi-purpose Grid cluster serving a community of twenty e-Science projects. The observed job statistics, resource utilisation and user behaviour is discussed in the context of management approaches and models most suitable for supporting a probabilistic and autonomous scheduling architecture.

  3. On-line grid impedance estimation based on harmonic injection for grid-connected PV inverter

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Teodorescu, Remus; Blaabjerg, Frede

    2007-01-01

    The paper presents an on-line software method for impedance estimation of the energized impedances such as power system grid. The proposed method is based on producing a perturbation on the output of the power converter that is in the form of periodical injection of one or two voltage harmonic...... two different signal processing algorithms. The DFT technique is used for the single harmonic injection and the statistic technique is used for the double harmonic injection. The grid impedance estimation is used for compliance with the anti-islanding requirements of the German standard (VDE0126...... signals. The single harmonic injection uses a 600 Hz signal and the double harmonic injection uses a 400 Hz and 600 Hz signals, respectively. During the perturbation, the current response(s) at the same frequency as the injected signal(s) is/are measured. The value of the grid impedance is estimated using...

  4. Modelling Chinese Smart Grid

    DEFF Research Database (Denmark)

    Yuksel, Ender; Nielson, Hanne Riis; Nielson, Flemming

    In this document, we consider a specific Chinese Smart Grid implementation and try to address the verification problem for certain quantitative properties including performance and battery consumption. We employ stochastic model checking approach and present our modelling and analysis study using...

  5. NSTAR Smart Grid Pilot

    Energy Technology Data Exchange (ETDEWEB)

    Rabari, Anil [NSTAR Electric, Manchester, NH (United States); Fadipe, Oloruntomi [NSTAR Electric, Manchester, NH (United States)

    2014-03-31

    NSTAR Electric & Gas Corporation (“the Company”, or “NSTAR”) developed and implemented a Smart Grid pilot program beginning in 2010 to demonstrate the viability of leveraging existing automated meter reading (“AMR”) deployments to provide much of the Smart Grid functionality of advanced metering infrastructure (“AMI”), but without the large capital investment that AMI rollouts typically entail. In particular, a central objective of the Smart Energy Pilot was to enable residential dynamic pricing (time-of-use “TOU” and critical peak rates and rebates) and two-way direct load control (“DLC”) by continually capturing AMR meter data transmissions and communicating through customer-sited broadband connections in conjunction with a standardsbased home area network (“HAN”). The pilot was supported by the U.S. Department of Energy’s (“DOE”) through the Smart Grid Demonstration program. NSTAR was very pleased to not only receive the funding support from DOE, but the guidance and support of the DOE throughout the pilot. NSTAR is also pleased to report to the DOE that it was able to execute and deliver a successful pilot on time and on budget. NSTAR looks for future opportunities to work with the DOE and others in future smart grid projects.

  6. Utah Bouguer Gravity Grid

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A 2.5 kilometer Bouguer anomaly grid for the state of Utah. Number of columns is 196 and number of rows is 245. The order of the data is from the lower left to the...

  7. Kids Enjoy Grids

    CERN Multimedia

    2007-01-01

    I want to come back and work here when I'm older,' was the spontaneous reaction of one of the children invited to CERN by the Enabling Grids for E-sciencE project for a 'Grids for Kids' day at the end of January. The EGEE project is led by CERN, and the EGEE gender action team organized the day to introduce children to grid technology at an early age. The school group included both boys and girls, aged 9 to 11. All of the presenters were women. 'In general, before this visit, the children thought that scientists always wore white coats and were usually male, with wild Einstein-like hair,' said Jackie Beaver, the class's teacher at the Institut International de Lancy, a school near Geneva. 'They were surprised and pleased to see that women became scientists, and that scientists were quite 'normal'.' The half-day event included presentations about why Grids are needed, a visit of the computer centre, some online games, and plenty of time for questions. In the end, everyone agreed that it was a big success a...

  8. Bolivian Bouguer Anomaly Grid

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A 1 kilometer Bouguer anomaly grid for the country of Bolivia.Number of columns is 550 and number of rows is 900. The order of the data is from the lower left to the...

  9. Minnesota Bouguer Anomaly Grid

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A 1.5 kilometer Bouguer anomaly grid for the state of Minnesota. Number of columns is 404 and number of rows is 463. The order of the data is from the lower left to...

  10. Ohio Bouguer Gravity Grid

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A 2 kilometer Bouguer anomaly grid for the state of Ohio. Number of columns is 187 and number of rows is 217. The order of the data is from the lower left to the...

  11. Grid attacks avian flu

    CERN Multimedia

    2006-01-01

    During April, a collaboration of Asian and European laboratories analysed 300,000 possible drug components against the avian flu virus H5N1 using the EGEE Grid infrastructure. Schematic presentation of the avian flu virus.The distribution of the EGEE sites in the world on which the avian flu scan was performed. The goal was to find potential compounds that can inhibit the activities of an enzyme on the surface of the influenza virus, the so-called neuraminidase, subtype N1. Using the Grid to identify the most promising leads for biological tests could speed up the development process for drugs against the influenza virus. Co-ordinated by CERN and funded by the European Commission, the EGEE project (Enabling Grids for E-sciencE) aims to set up a worldwide grid infrastructure for science. The challenge of the in silico drug discovery application is to identify those molecules which can dock on the active sites of the virus in order to inhibit its action. To study the impact of small scale mutations on drug r...

  12. Control of a grid connected converter during weak grid conditions

    DEFF Research Database (Denmark)

    Lorenzen, Søren Lund; Nielsen, Alex Buus; Bede, L.

    2016-01-01

    the case for offshore wind turbines. This can cause the wind farm grid networks to be weak. A weak network is an extra challenge to inject energy into, since it might exceed grid codes and grid standard values, if not compensated for. To ensure quality of the energy injected to the network, a Voltage...

  13. Implementation of Computational Grid Services in Enterprise Grid Environments

    Directory of Open Access Journals (Sweden)

    R. J.A. Richard

    2008-01-01

    Full Text Available Grid Computing refers to the development of high performance computing environment or virtual super computing environment by utilizing available computing resources in a LAN, WAN and Internet. This new emerging research field offers enormous opportunities for e-Science applications such as astrophysics, bioinformatics, aerospace modeling, cancer research etc. Grid involves coordinating and sharing of computing power, application, data storage, network resources etc., across dynamically and geographically dispersed organizations. Most Grid environments are developed using Globus toolkit which is a UNIX/Linux based middleware to integrate computational resources over the network. The emergence of Global Grid concept provides an excellent opportunity for Grid based e-Science applications to use high performance super computing environments. Thus windows based enterprise grid environments can't be neglected in the development of Global Grids. This study discusses the basics of enterprise grids and the implementation of enterprise computational grids using Alchemi Tool Kit. This review study is organized into three parts. They are (i Introduction of Grid Technologies, (ii Design Concepts of Enterprise Grids and (iii Implementation of Computational Grid Services.

  14. 基于推挽正激电路的准单级式光伏并网逆变器仿真分析%Simulation Analysis on Quasi-Single-stage Grid-Connected Photovoltaic Inverter Based on Push-pull Forward Converter

    Institute of Scientific and Technical Information of China (English)

    陈峰; 陈道炼

    2012-01-01

    A single-stage grid-connected photovoltaic system was investigated to overcome the drawbacks of two-stage gridconnected photovoltaic system such as complex structure, high cost and low efficiency. It has researched the grid-connected current sinusoidal control, maximum power point tracking (MPPT) and the system stability under the rapidly change of light intensity, which were based on the instantaneous current feedback control, dual mode MPPT and DC-link voltage feed-forward control. At last, the model of 300VA PV grid-connected system was built and simulated to verify the theoretical analysis. The research results demonstrate that the single-stage grid-connected system have many advantages such as high quality and good dynamic characteristics of grid- connected current, accuracy MPPT, high efficiency, strong adaptability to the rapidly change of light intensity, high reliability etc. Therefore, it can be deduced that this kind of PV system has a wide application prospect in the place where the grid-connected inverter requires electrical isolation.%针对两级式光伏并网逆变系统结构复杂、成本高、效率低的不足,研究了一种单级式光伏并网逆变系统。采用电流瞬时值反馈控制、双模式MPPT算法和直流母线电压前馈控制的方法,研究了单级式光伏并网逆变系统并网电流的正弦控制、最大功率点跟踪控制和光照突变下系统的稳定性,并对300VA光伏并网逆变系统进行了建模仿真。研究结果表明,单级式光伏并网逆变系统具有并网电流质量高、动态特性好、最大功率点跟踪精确、效率高、光照突变适应性强、稳定性高等优点,在要求电气隔离的分布式并网逆变场合具有广阔的应用前景。

  15. Impact of intracoronary injection of mononuclear bone marrow cells in acute myocardial infarction on left ventricular perfusion and function: a 6-month follow-up gated {sup 99m}Tc-MIBI single-photon emission computed tomography study

    Energy Technology Data Exchange (ETDEWEB)

    Lipiec, Piotr [Medical University of Lodz, 2nd Department of Cardiology, Lodz (Poland); Medical University of Lodz, 2nd Department of Cardiology, Bieganski Hospital, Lodz (Poland); Krzeminska-Pakula, Maria; Plewka, Michal; Kasprzak, Jaroslaw D. [Medical University of Lodz, 2nd Department of Cardiology, Lodz (Poland); Kusmierek, Jacek; Plachcinska, Anna; Szuminski, Remigiusz [Medical University of Lodz, Department of Nuclear Medicine, Lodz (Poland); Robak, Tadeusz; Korycka, Anna [Medical University of Lodz, Department of Hematology, Lodz (Poland)

    2009-04-15

    We investigated the impact of intracoronary injection of autologous mononuclear bone marrow cells (BMC) in patients with acute ST elevation myocardial infarction (STEMI) on left ventricular volumes, global and regional systolic function and myocardial perfusion. The study included 39 patients with first anterior STEMI treated successfully with primary percutaneous coronary intervention. They were randomly assigned to the treatment group or the control group in a 2:1 ratio. The patients underwent baseline gated single-photon emission computed tomography (G-SPECT) 3-10 days after STEMI with quantitative and qualitative analysis of left ventricular perfusion and systolic function. On the following day, patients from the BMC treatment group were subjected to bone marrow aspiration, mononuclear BMC isolation and intracoronary injection. No placebo procedure was performed in the control group. G-SPECT was repeated 6 months after STEMI. Baseline and follow-up G-SPECT studies were available for 36 patients. At 6 months in the BMC group we observed a significantly enhanced improvement in the mean extent of the perfusion defect, the left ventricular perfusion score index, the infarct area perfusion score and the infarct area wall motion score index compared to the control group (p=0.01-0.04). However, the changes in left ventricular volume, ejection fraction and the left ventricular wall motion score index as well as the relative changes in the infarct area wall motion score index did not differ significantly between the groups. Intracoronary injection of autologous mononuclear BMC in patients with STEMI improves myocardial perfusion at 6 months. The benefit in infarct area systolic function is less pronounced and there is no apparent improvement of global left ventricular systolic function. (orig.)

  16. HIRENASD Unstructured Grids - Centaur software

    Data.gov (United States)

    National Aeronautics and Space Administration — These grids were constructed using Centaur software at DLR in Germany. The grids designed for node based (labeled 'cv') and cell-centered solvers (labeled 'cc') are...

  17. Allegheny County Map Index Grid

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Map Index Sheets from Block and Lot Grid of Property Assessment and based on aerial photography, showing 1983 datum with solid line and NAD 27 with 5 second grid...

  18. Allegheny County Map Index Grid

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — Map Index Sheets from Block and Lot Grid of Property Assessment and based on aerial photography, showing 1983 datum with solid line and NAD 27 with 5 second grid...

  19. Applications of algebraic grid generation

    Science.gov (United States)

    Eiseman, Peter R.; Smith, Robert E.

    1990-01-01

    Techniques and applications of algebraic grid generation are described. The techniques are univariate interpolations and transfinite assemblies of univariate interpolations. Because algebraic grid generation is computationally efficient, the use of interactive graphics in conjunction with the techniques is advocated. A flexible approach, which works extremely well in an interactive environment, called the control point form of algebraic grid generation is described. The applications discussed are three-dimensional grids constructed about airplane and submarine configurations.

  20. Towards a Semantic Grid Architecture

    OpenAIRE

    Goble, Carole

    2005-01-01

    The Semantic Grid is an extension of the current Grid in which information and services are given well defined and explicitly represented meaning, better enabling computers and people to work in cooperation. In the last few years, several projects have embraced this vision and there are already successful pioneering applications that combine the strengths of the Grid and of semantic technologies. However, the Semantic Grid currently lacks a reference architecture, or a systematic approach for...

  1. Grid3: An Application Grid Laboratory for Science

    CERN Document Server

    CERN. Geneva

    2004-01-01

    level services required by the participating experiments. The deployed infrastructure has been operating since November 2003 with 27 sites, a peak of 2800 processors, work loads from 10 different applications exceeding 1300 simultaneous jobs, and data transfers among sites of greater than 2 TB/day. The Grid3 infrastructure was deployed from grid level services provided by groups and applications within the collaboration. The services were organized into four distinct "grid level services" including: Grid3 Packaging, Monitoring and Information systems, User Authentication and the iGOC Grid Operatio...

  2. Grid Interaction Technical Team Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-06-01

    The mission of the Grid Interaction Technical Team (GITT) is to support a transition scenario to large scale grid-connected vehicle charging with transformational technology, proof of concept and information dissemination. The GITT facilitates technical coordination and collaboration between vehicle-grid connectivity and communication activities among U.S. DRIVE government and industry partners.

  3. Smart grid: hope or hype?

    DEFF Research Database (Denmark)

    Lunde, Morten; Røpke, Inge; Heiskanen, Eva

    2016-01-01

    The smart grid is an important but ambiguous element in the future transition of the European energy system. The current paper unpacks one influential national vision of the smart grid to identify what kinds of expectations guide the work of smart grid innovators and how the boundaries of the sma...

  4. Change of Serum BNP Between Admission and Discharge After Acute Decompensated Heart Failure Is a Better Predictor of 6-Month All-Cause Mortality Than the Single BNP Value Determined at Admission

    Science.gov (United States)

    De Vecchis, Renato; Ariano, Carmelina; Giandomenico, Giuseppe; Di Maio, Marco; Baldi, Cesare

    2016-01-01

    Background B-type natriuretic peptide (BNP) is regarded as a reliable predictor of outcome in patients with acute decompensated heart failure (ADHF). However, according to some scholars, a single isolated measurement of serum BNP at the time of hospital admission would not be sufficient to provide reliable prognostic information. Methods A retrospective study was carried out on patients hospitalized for ADHF, who had then undergone follow-up of at least 6 months, in order to see if there was any difference in midterm mortality among patients with rising BNP at discharge as compared to those with decreasing BNP at discharge. Medical records had to be carefully examined to divide the case records into two groups, the former characterized by an increase in BNP during hospitalization, and the latter showing a decrease in BNP from the time of admission to the time of discharge. Results Ultimately, 177 patients were enrolled in a retrospective study. Among them, 53 patients (29.94%) had increased BNPs at the time of discharge relative to admission, whereas 124 (70.06%) exhibited decreases in serum BNP during their hospital stay. The group with patients who exhibited BNP increases at the time of discharge had higher degree of congestion evident in the higher frequency of persistent jugular venous distention (odds ratio: 3.72; P = 0.0001) and persistent orthopnea at discharge (odds ratio: 2.93; P = 0.0016). Moreover, patients with increased BNP at the time of discharge had a lower reduction in inferior vena cava maximum diameter (1.58 ± 2.2 mm vs. 6.32 ± 1.82 mm; P = 0.001 (one-way ANOVA)). In contrast, there was no significant difference in weight loss when patients with increased BNP at discharge were compared to those with no such increase. A total of 14 patients (7.9%) died during the 6-month follow-up period. Cox proportional hazard analysis revealed that BNP increase at the time of discharge was an independent predictor of 6-month all-cause mortality after

  5. Cloud Computing for the Grid: GridControl: A Software Platform to Support the Smart Grid

    Energy Technology Data Exchange (ETDEWEB)

    None

    2012-02-08

    GENI Project: Cornell University is creating a new software platform for grid operators called GridControl that will utilize cloud computing to more efficiently control the grid. In a cloud computing system, there are minimal hardware and software demands on users. The user can tap into a network of computers that is housed elsewhere (the cloud) and the network runs computer applications for the user. The user only needs interface software to access all of the cloud’s data resources, which can be as simple as a web browser. Cloud computing can reduce costs, facilitate innovation through sharing, empower users, and improve the overall reliability of a dispersed system. Cornell’s GridControl will focus on 4 elements: delivering the state of the grid to users quickly and reliably; building networked, scalable grid-control software; tailoring services to emerging smart grid uses; and simulating smart grid behavior under various conditions.

  6. Grid today, clouds on the horizon

    CERN Document Server

    Shiers, Jamie

    2009-01-01

    By the time of CCP 2008, the largest scientific machine in the world – the Large Hadron Collider – had been cooled down as scheduled to its operational temperature of below 2 degrees Kelvin and injection tests were starting. Collisions of proton beams at 5+5 TeV were expected within one to two months of the initial tests, with data taking at design energy (7+7 TeV) foreseen for 2009. In order to process the data from this world machine, we have put our “Higgs in one basket” – that of Grid computing [The Worldwide LHC Computing Grid (WLCG), in: Proceedings of the Conference on Computational Physics 2006 (CCP 2006), vol. 177, 2007, pp. 219–223]. After many years of preparation, 2008 saw a final “Common Computing Readiness Challenge” (CCRC'08) – aimed at demonstrating full readiness for 2008 data taking, processing and analysis. By definition, this relied on a world-wide production Grid infrastructure. But change – as always – is on the horizon. The current funding model for Grids – which...

  7. Resilient Grid Operational Strategies

    Energy Technology Data Exchange (ETDEWEB)

    Pasqualini, Donatella [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-01

    Extreme weather-related disturbances, such as hurricanes, are a leading cause of grid outages historically. Although physical asset hardening is perhaps the most common way to mitigate the impacts of severe weather, operational strategies may be deployed to limit the extent of societal and economic losses associated with weather-related physical damage.1 The purpose of this study is to examine bulk power-system operational strategies that can be deployed to mitigate the impact of severe weather disruptions caused by hurricanes, thereby increasing grid resilience to maintain continuity of critical infrastructure during extreme weather. To estimate the impacts of resilient grid operational strategies, Los Alamos National Laboratory (LANL) developed a framework for hurricane probabilistic risk analysis (PRA). The probabilistic nature of this framework allows us to estimate the probability distribution of likely impacts, as opposed to the worst-case impacts. The project scope does not include strategies that are not operations related, such as transmission system hardening (e.g., undergrounding, transmission tower reinforcement and substation flood protection) and solutions in the distribution network.

  8. A Single-phase Diode Clamped Transformerless PV Grid-connected Inverter%一种二极管无源钳位的单相无变压器型光伏并网逆变拓扑研究

    Institute of Scientific and Technical Information of China (English)

    王金华; 顾云杰; 胡斯登; 李武华; 何湘宁; 曹丰文

    2015-01-01

    A single-phase transformerless grid-connected photovoltaic (PV) inverter topology was proposed based on diode clamped method. The proposed circuit provides an effective improvement in common-mode current rejection capability, compared with state-of-the-art dc/ac decoupled solutions such as the H5 topology. In the proposed method, an extra voltage clamped path is inserted in an ac-decoupled transformerless inverter through two passive diodes. As a result, the common-mode voltage is clamped by the dc capacitor to eliminate the possible high-frequency common-mode oscillations caused by power device parasitic capacitors, which is the major cause of leakage current in dc/ac decoupled transformerless topologies. The proposed passive clamped technique features cost effective solution with no additional active switches, in comparison with the active clamping counterpart. The performance of the proposed topology has been verified by simulation and experiment with a 2kW prototype.%提出一种基于二极管无源钳位思想的单相无变压器型光伏并网逆变器拓扑。与H5等传统电路相比,本拓扑具有更好的对地漏电流抑制能力。目前主流的单相无变压器型逆变电路普遍采用直流或交流解耦技术,阻断共模电流的流通路径。但是,功率开关上的寄生电容可能与共模电抗形成谐振回路,使得共模电流无法彻底消除。以H5拓扑为例,定量分析功率器件寄生电容影响共模电流的机理。针对这一问题,引入无源二极管钳位电路,使得共模电压被母线电容中点钳位,从而抑制了功率器件寄生电容引起的共模电压振荡,更有效地消除对地漏电流。在理论和仿真分析的基础上,通过搭建2 kW实验平台验证所提拓扑的性能。结果表明,改进拓扑相对于原拓扑而言,能更好地抑制对地漏电流,提高了无变压器型光伏并网系统的安全裕度。

  9. Monthly Meteorological Reports

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly forms that do not fit into any regular submission. Tabulation sheets and generic monthly forms designed to capture miscellaneous monthly observations.

  10. Research on 1 kW Single-Phase Photovoltaic Grid-Connected Phase-Locked Technology Based on DSP%基于DSP的1 kW单相光伏并网锁相技术的研究

    Institute of Scientific and Technical Information of China (English)

    许军; 郑绍陆; 唐传鋆; 耿力

    2014-01-01

    As to the problem,PV( Photo-Voltage) grid-connected distributed power supply system's phase locking, this paper proposes a photovoltaic grid-connected system's digital phase-locked algorithm and program flow design based on DSP. According to the relationship between the period and phase of the cycle of adjustment,the control cycle and phase locking are realized. By this method,conveniently the grid voltage and PV power generation output current signal and the objectives of signal capture and phase-locked are realized. Finally,implement of the prototype and the experimental results proved that the method is accurate. The design ensures PLL method accuracy,reliability and practicability of the PV grid-connected system.%针对光伏分布式电源并网系统锁相技术的问题,采用了一种基于DSP的光伏并网系统的数字锁相算法和程序流程设计,根据周期和相位的关系,通过调整周期来实现周期和相位的控制和锁定,方便地实现了对电网电压和光伏发电输出电流信号捕获和锁相的目的。最后制作样机并通过实验证明,该锁相方法设计准确,锁相精度高,保证了光伏并网系统的可靠性和实用性。

  11. Smart Grid Risk Management

    Science.gov (United States)

    Abad Lopez, Carlos Adrian

    Current electricity infrastructure is being stressed from several directions -- high demand, unreliable supply, extreme weather conditions, accidents, among others. Infrastructure planners have, traditionally, focused on only the cost of the system; today, resilience and sustainability are increasingly becoming more important. In this dissertation, we develop computational tools for efficiently managing electricity resources to help create a more reliable and sustainable electrical grid. The tools we present in this work will help electric utilities coordinate demand to allow the smooth and large scale integration of renewable sources of energy into traditional grids, as well as provide infrastructure planners and operators in developing countries a framework for making informed planning and control decisions in the presence of uncertainty. Demand-side management is considered as the most viable solution for maintaining grid stability as generation from intermittent renewable sources increases. Demand-side management, particularly demand response (DR) programs that attempt to alter the energy consumption of customers either by using price-based incentives or up-front power interruption contracts, is more cost-effective and sustainable in addressing short-term supply-demand imbalances when compared with the alternative that involves increasing fossil fuel-based fast spinning reserves. An essential step in compensating participating customers and benchmarking the effectiveness of DR programs is to be able to independently detect the load reduction from observed meter data. Electric utilities implementing automated DR programs through direct load control switches are also interested in detecting the reduction in demand to efficiently pinpoint non-functioning devices to reduce maintenance costs. We develop sparse optimization methods for detecting a small change in the demand for electricity of a customer in response to a price change or signal from the utility

  12. GridTool: A surface modeling and grid generation tool

    Science.gov (United States)

    Samareh-Abolhassani, Jamshid

    1995-01-01

    GridTool is designed around the concept that the surface grids are generated on a set of bi-linear patches. This type of grid generation is quite easy to implement, and it avoids the problems associated with complex CAD surface representations and associated surface parameterizations. However, the resulting surface grids are close to but not on the original CAD surfaces. This problem can be alleviated by projecting the resulting surface grids onto the original CAD surfaces. GridTool is designed primary for unstructured grid generation systems. Currently, GridTool supports VGRID and FELISA systems, and it can be easily extended to support other unstructured grid generation systems. The data in GridTool is stored parametrically so that once the problem is set up, one can modify the surfaces and the entire set of points, curves and patches will be updated automatically. This is very useful in a multidisciplinary design and optimization process. GridTool is written entirely in ANSI 'C', the interface is based on the FORMS library, and the graphics is based on the GL library. The code has been tested successfully on IRIS workstations running IRIX4.0 and above. The memory is allocated dynamically, therefore, memory size will depend on the complexity of geometry/grid. GridTool data structure is based on a link-list structure which allows the required memory to expand and contract dynamically according to the user's data size and action. Data structure contains several types of objects such as points, curves, patches, sources and surfaces. At any given time, there is always an active object which is drawn in magenta, or in their highlighted colors as defined by the resource file which will be discussed later.

  13. Research on SOGI for phase lock technique of the single-phase grid-connected system%基于二阶广义积分器的单相并网系统锁相技术的研究

    Institute of Scientific and Technical Information of China (English)

    侯立健; 朱长青; 陈雅; 严雪飞

    2016-01-01

    For the grid voltage is usually affected by disturbance and harmonic, so in the synchronous application of grid-connected converter, there is a phase difference between grid-connected current and grid voltage, which will have impact and pollution to the power grid.The practical experience shows that some phase locked loop(PLL) based quadrature signal generator( QSG) has better performance.This paper adopts the second-order general integrator( SO-GI) that is improved, and frequency of SOGI automatically tracks the input frequency through a simple control loop instead of trigonometric function.Finally, this scheme constructs new-style structure of the frequency locked loop with PLL module.This scheme is easy to design and implement, simulation results show its excellent performance, and the frequency and angle can be detected rapidly and do not contain a steady oscillation, the feasibility and the superiority of the scheme are verified.%由于电网电压通常受到扰动和谐波的影响,因此在并网变换器的同步应用中,并网电流和电网存在相位差,会对电网产生冲击和污染。实践经验表明基于某种正交信号发生器( QSG)的锁相环( PLL)具有更好的性能。文章采用基于二阶广义积分器( SOGI)的正交信号发生器,并加以改进,在无需使用三角函数的情况下,设计一个简单的控制环将SOGI谐振器中心频率自适应调节为输入频率,并去除PLL模块,构造了新型的锁频环( FLL)结构。仿真结果表明,该方法不仅易于设计和实现,同时其性能优异,频率和相角的检测速度较快,且不含有稳态振荡,验证了方案的可行性和优越性。

  14. A Hierarchical Load Balancing Policy for Grid Computing Environment

    Directory of Open Access Journals (Sweden)

    Said Fathy El Zoghdy

    2012-06-01

    Full Text Available With the rapid development of high-speed wide-area networks and powerful yet low-cost computational resources, grid computing has emerged as an attractive computing paradigm. It provides resources for solving large scientific applications. It is typically composed of heterogeneous resources such as clusters or sites at different administrative domains connected by networks with widely varying performance characteristics. The service level of the grid software infrastructure provides two essential functions for workload and resource management. To efficiently utilize the resources at these environments, effective load balancing and resource management policies are fundamentally important. This paper addresses the problem of load balancing and task migration in grid computing environments. We propose a fully decentralized two-level load balancing policy for computationally intensive tasks on a heterogeneous multi-cluster grid environment. It resolves the single point of failure problem which many of the current policies suffer from. In this policy, any site manager receives two kinds of tasks namely, remote tasks arriving from its associated local grid manager, and local tasks submitted directly to the site manager by local users in its domain, which makes this policy closer to reality and distinguishes it from any other similar policy. It distributes the grid workload based on the resources occupation ratio and the communication cost. The grid overall mean task response time is considered as the main performance metric that need to be minimized. The simulation results show that the proposed load balancing policy improves the grid overall mean task response time.

  15. Four Factor Secure Authentication and Authorization for Economic Grid

    Directory of Open Access Journals (Sweden)

    M. Victor Jose

    2014-03-01

    Full Text Available In this study, a low cost virtually single storage private grid has been implemented as an economic one. In this economic grid that has been overcome, without scheduling resource down problem and needs of dedicated resource storage. The resource storage is done within a virtual single private grid nodes using random object addressing to prevent stolen attack. If any grid resource goes down, its resource identity will be removed from the resource object table that is maintained in middleware and resource recovery is efficiently managed by replicas. To overcome the limitation of biometric authentication and maintain the secret privacy this authentication uses four factors such as username and password, Universal Unique Identifier (UUID of Operating System, Mother Board serial number and MAC address. IP address spoofing is overcome by using Secret Token. This Secret token is generated using UUID of operating System, mother board serial number and MAC address. This proposed system is used in grid, sharing of messages between source and destination which prevents attacks and maintains privacy, integrity of data. This private grid is simulated in GridSim Toolkit 5.2 with various criteria and the results are verified and displayed.

  16. Suggested Grid Code Modifications to Ensure Wide-Scale Adoption of Photovoltaic Energy in Distributed Power Generation Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Enjeti, Prasad; Blaabjerg, Frede;

    2013-01-01

    -phase PV systems in the distributed grid, the disconnection under grid faults can contribute to: a) voltage flickers, b) power outages, and c) system instability. In this paper, grid code modifications are explored for wide-scale adoption of PV systems in the distribution grid. More recently, Italy......Current grid standards seem to largely require low power (e.g. several kilowatts) single-phase photovoltaic (PV) systems to operate at unity power factor with maximum power point tracking, and disconnect from the grid under grid faults. However, in case of a wide-scale penetration of single...... and Japan, have undertaken a major review of standards for PV power conversion systems connected to low voltage networks. In view of this, the importance of low voltage ride-through for single-phase PV power systems under grid faults along with reactive power injection is studied in this paper. Three...

  17. 3D measurement of absolute radiation dose in grid therapy

    Energy Technology Data Exchange (ETDEWEB)

    Trapp, J V [Joint Department of Physics, Institute of Cancer Research and Royal Marsden Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT (United Kingdom); Department of Applied Physics, RMIT University, GPO Box 2476V, Melbourne 3001 (Australia); Warrington, A P [Joint Department of Physics, Institute of Cancer Research and Royal Marsden Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT (United Kingdom); Partridge, M [Joint Department of Physics, Institute of Cancer Research and Royal Marsden Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT (United Kingdom); Philps, A [Joint Department of Physics, Institute of Cancer Research and Royal Marsden Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT (United Kingdom); Leach, M O [Cancer Research UK Clinical MR Research Group, Institute of Cancer Research and Royal Marsden Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT (United Kingdom); Webb, S [Joint Department of Physics, Institute of Cancer Research and Royal Marsden Foundation Trust, Downs Road, Sutton, Surrey SM2 5PT (United Kingdom)

    2004-01-01

    Spatially fractionated radiotherapy through a grid is a concept which has a long history and was routinely used in orthovoltage radiation therapy in the middle of last century to minimize damage to the skin and subcutaneous tissue. With the advent of megavoltage radiotherapy and its skin sparing effects the use of grids in radiotherapy declined in the 1970s. However there has recently been a revival of the technique for use in palliative treatments with a single fraction of 10 to 20 Gy. In this work the absolute 3D dose distribution in a grid irradiation is measured for photons using a combination of film and gel dosimetry.

  18. Faster GPU-based convolutional gridding via thread coarsening

    CERN Document Server

    Merry, Bruce

    2016-01-01

    Convolutional gridding is a processor-intensive step in interferometric imaging. While it is possible to use graphics processing units (GPUs) to accelerate this operation, existing methods use only a fraction of the available flops. We apply thread coarsening to improve the efficiency of an existing algorithm, and observe performance gains of up to $3.2\\times$ for single-polarization gridding and $1.9\\times$ for quad-polarization gridding on a GeForce GTX 980, and smaller but still significant gains on a Radeon R9 290X.

  19. NEW RESULTS FROM TESTING OF COPLANAR-GRID CDZNTE DETECTOR.

    Energy Technology Data Exchange (ETDEWEB)

    CARINI, G.A.; ET AL.

    2005-07-31

    New results from studies of coplanar-grid CdZnTe (CZT) detectors are presented. The coplanar-grid detectors, were investigated by using a highly collimated X-ray beam available at Brookhaven's National Synchrotron Light Source and by applying a pulse-shape analysis. The coplanar-grid detector operates as a single-carrier device. Despite the fact that its operational principle is well known and has been investigated by many groups in the past, we found some new details that may explain the performance limits of these types of devices. The experimental results have been confirmed by extensive computer modeling.

  20. Faster GPU-based convolutional gridding via thread coarsening

    Science.gov (United States)

    Merry, B.

    2016-07-01

    Convolutional gridding is a processor-intensive step in interferometric imaging. While it is possible to use graphics processing units (GPUs) to accelerate this operation, existing methods use only a fraction of the available flops. We apply thread coarsening to improve the efficiency of an existing algorithm, and observe performance gains of up to 3.2 × for single-polarization gridding and 1.9 × for quad-polarization gridding on a GeForce GTX 980, and smaller but still significant gains on a Radeon R9 290X.

  1. A Grid Sourcing and Adaptation Study Using Unstructured Grids for Supersonic Boom Prediction

    Science.gov (United States)

    Carter, Melissa B.; Deere, Karen A.

    2008-01-01

    NASA created the Supersonics Project as part of the NASA Fundamental Aeronautics Program to advance technology that will make a supersonic flight over land viable. Computational flow solvers have lacked the ability to accurately predict sonic boom from the near to far field. The focus of this investigation was to establish gridding and adaptation techniques to predict near-to-mid-field (sources along the body the aircraft, far field sourcing and far field boundaries. The study then examined several techniques for grid adaptation. During the course of the study, volume sourcing was introduced as a new way to source grids using the grid generation code VGRID. Two different methods of using the volume sources were examined. The first method, based on manual insertion of the numerous volume sources, made great improvements in the prediction capability of USM3D for boom signatures. The second method (SSGRID), which uses an a priori adaptation approach to stretch and shear the original unstructured grid to align the grid and pressure waves, showed similar results with a more automated approach. Due to SSGRID s results and ease of use, the rest of the study focused on developing a best practice using SSGRID. The best practice created by this study for boom predictions using the CFD code USM3D involved: 1) creating a small cylindrical outer boundary either 1 or 2 body lengths in diameter (depending on how far below the aircraft the boom prediction is required), 2) using a single volume source under the aircraft, and 3) using SSGRID to stretch and shear the grid to the desired length.

  2. Embodied Energy and Off-Grid Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Alstone, Peter; Mills, Evan; Jacobson, Arne

    2011-01-25

    The greenhouse gas (GHG) emissions from fuel-based lighting are substantial given the paltry levels of lighting service provided to users, leading to a great opportunity for GHG mitigation byencouraging the switch from fuel-based to rechargeable LED lighting. However, as with most new energy technology, switching to efficient lighting requires an up-front investment of energy(and GHGs) embedded in the manufacture of replacement components. We studied a population of off-grid lighting users in 2008-2009 in Kenya who were given the opportunity to adopt LEDlighting. Based on their use patterns with the LED lights and the levels of kerosene offset we observed, we found that the embodied energy of the LED lamp was"paid for" in only one month for grid charged products and two months for solar charged products. Furthermore, the energyreturn-on investment-ratio (energy produced or offset over the product's service life divided by energy embedded) for off-grid LED lighting ranges from 12 to 24, which is on par with on-gridsolar and large-scale wind energy. We also found that the energy embodied in the manufacture of a typical hurricane lantern is about one-half to one-sixth of that embodied in the particular LEDlights that we evaluated, indicating that the energy payback time would be moderately faster if LEDs ultimately displace the production of kerosene lanterns. As LED products improve, weanticipate longer service lives and more successful displacement of kerosene lighting, both of which will speed the already rapid recovery of embodied energy in these products. Our studyprovides a detailed appendix with embodied energy values for a variety of components used to construct off-grid LED lighting, which can be used to analyze other products.

  3. Double-blind controlled trial of a single dose of the combination ivermectin 400 micrograms/kg plus diethylcarbamazine 6 mg/kg for the treatment of bancroftian filariasis: results at six months.

    Science.gov (United States)

    Glaziou, P; Moulia-Pelat, J P; Nguyen, L N; Chanteau, S; Martin, P M; Cartel, J L

    1994-01-01

    In 1993, a three-arm double-blind controlled trial was implemented in French Polynesia to compare the tolerance and efficacy of a single dose of the combination ivermectin (IVR) 400 micrograms/kg plus diethylcarbamazine (DEC) 6 mg/kg vs. IVR 400 micrograms/kg alone vs. DEC 6 mg/kg alone, for treatment of Wuchereria bancrofti carriers. Of the 57 treated male patients in whom microfilaria (mf) densities ranged from 22 to 4709 mg/mL, 3 groups of 19 were randomly selected and allocated to one of the 3 treatments. Side effects were experienced by 34 patients (60%), but none suffered a severe reaction. Grade of reaction did not differ between treatment group, but was significantly correlated with the pretreatment mf density. Six months after treatment, 26%, 32% and 53% of patients were amicrofilaraemic in the DEC, IVR and IVR+DEC groups, respectively. Mf levels were 6.3%, and 3.1% and 1.0% of the pretreatment level, respectively, significantly lower in the IVR+DEC group than in both the IVR and DEC comparison groups. The combination IVR+DEC showed promise in term of sustained mf decrease, and could be an effective alternative for lymphatic filariasis control programmes.

  4. Smart power grids 2011

    CERN Document Server

    Keyhani, Ali

    2012-01-01

    Electric power systems are experiencing significant changes at the worldwide scale in order to become cleaner, smarter, and more reliable. This edited book examines a wide range of topics related to these changes, which are primarily caused by the introduction of information technologies, renewable energy penetration, digitalized equipment, new operational strategies, and so forth. The emphasis will be put on the modeling and control of smart grid systems. This book addresses research topics such as high efficiency transforrmers, wind turbines and generators, fuel cells, or high speed turbines

  5. The Knowledge Grid

    CERN Document Server

    Zhuge, Hai

    2004-01-01

    The Knowledge Grid is an intelligent and sustainable interconnection environment that enables people and machines to effectively capture, publish, share and manage knowledge resources. It also provides appropriate on-demand services to support scientific research, technological innovation, cooperative teamwork, problem solving, and decision making. It incorporates epistemology and ontology to reflect human cognitive characteristics; exploits social, ecological and economic principles; and adopts techniques and standards developed during work toward the future web. This book presents its methodology, theory, models and applications systematically for the first time.

  6. myGrid: personalised bioinformatics on the information grid.

    Science.gov (United States)

    Stevens, Robert D; Robinson, Alan J; Goble, Carole A

    2003-01-01

    The (my)Grid project aims to exploit Grid technology, with an emphasis on the Information Grid, and provide middleware layers that make it appropriate for the needs of bioinformatics. (my)Grid is building high level services for data and application integration such as resource discovery, workflow enactment and distributed query processing. Additional services are provided to support the scientific method and best practice found at the bench but often neglected at the workstation, notably provenance management, change notification and personalisation. We give an overview of these services and their metadata. In particular, semantically rich metadata expressed using ontologies necessary to discover, select and compose services into dynamic workflows.

  7. Integrating Renewable Electricity on the Grid

    Science.gov (United States)

    Crabtree, George; Misewich, Jim; Ambrosio, Ron; Clay, Kathryn; DeMartini, Paul; James, Revis; Lauby, Mark; Mohta, Vivek; Moura, John; Sauer, Peter; Slakey, Francis; Lieberman, Jodi; Tai, Humayun

    2011-11-01

    The demand for carbon-free electricity is driving a growing movement of adding renewable energy to the grid. Renewable Portfolio Standards mandated by states and under consideration by the federal government envision a penetration of 20-30% renewable energy in the grid by 2020 or 2030. The renewable energy potential of wind and solar far exceeds these targets, suggesting that renewable energy ultimately could grow well beyond these initial goals. The grid faces two new and fundamental technological challenges in accommodating renewables: location and variability. Renewable resources are concentrated at mid-continent far from population centers, requiring additional long distance, high-capacity transmission to match supply with demand. The variability of renewables due to the characteristics of weather is high, up to 70% for daytime solar due to passing clouds and 100% for wind on calm days, much larger than the relatively predictable uncertainty in load that the grid now accommodates by dispatching conventional resources in response to demand. Solutions to the challenges of remote location and variability of generation are needed. The options for DC transmission lines, favored over AC lines for transmission of more than a few hundred miles, need to be examined. Conventional high voltage DC transmission lines are a mature technology that can solve regional transmission needs covering one- or two-state areas. Conventional high voltage DC has drawbacks, however, of high loss, technically challenging and expensive conversion between AC and DC, and the requirement of a single point of origin and termination. Superconducting DC transmission lines lose little or no energy, produce no heat, and carry higher power density than conventional lines. They operate at moderate voltage, allowing many "on-ramps" and "off-ramps" in a single network and reduce the technical and cost challenges of AC to DC conversion. A network of superconducting DC cables overlaying the existing

  8. Workshop on Future Generation Grids

    CERN Document Server

    Laforenza, Domenico; Reinefeld, Alexander

    2006-01-01

    The Internet and the Web continue to have a major impact on society. By allowing us to discover and access information on a global scale, they have created entirely new businesses and brought new meaning to the term surf. In addition, however, we want processing, and increasingly, we want collaborative processing within distributed teams. This need has led to the creation of the Grid - an infrastructure that enables us to share capabilities, and integrate services and resources within and across enterprises. "Future Generation Grids" is the second in the "CoreGRID" series. This edited volume brings together contributed articles by scientists and researchers in the Grid community in an attempt to draw a clearer picture of the future generation Grids. This book also identifies some of the most challenging problems on the way to achieving the invisible Grid ideas

  9. Synchrony-optimized power grids

    CERN Document Server

    Pinto, Rafael S

    2014-01-01

    We investigate synchronization in power grids, which we assume to be modeled by a network of Kuramoto oscillators with inertia. More specifically, we study the optimization of the power grid topology to favor the network synchronization. We introduce a rewiring algorithm which consists basically in a hill climb scheme where the edges of the network are swapped in order enhance the main measures of synchronization. As a byproduct of the optimization algorithm, we typically have also the anticipation of the synchronization onset for the optimized network. We perform several robustness tests for the synchrony-optimized power grids, including the impact of consumption peaks. In our analyses, we investigate synthetic random networks, which we consider as hypothetical decentralized power generation situations, and also a network based in the actual power grid of Spain, which corresponds to the current paradigm of centralized power grids. The synchrony-optimized power grids obtained by our algorithm have some intere...

  10. Hybrid damping strategy for single-phase grid-connected PV inverter under the control of PDFI%PDFI 控制下单相光伏并网逆变器的混合阻尼控制策略

    Institute of Scientific and Technical Information of China (English)

    杨秋霞; 李坤; 王虎; 赵翠妹

    2016-01-01

    传统的比例积分(PI)控制由于具有一定的稳态误差,无法实现对并网电流快速精确的控制,光伏系统并网以后所引入的电网电感对 LCL 滤波器的阻尼策略也有着不可忽略的影响。为了解决上述问题,提出了一种 PDFI控制下单相光伏并网逆变器的混合阻尼控制策略。该策略介绍了比例延时反馈积分(PDFI)控制,在原有的 PI 控制上加上简单反馈电路,实现了并网电流的无稳态误差控制。同时分析了以阻尼系数为研究对象的混合阻尼控制,改善了电网电感对 LCL 滤波器的阻尼影响。理论分析、实例仿真的结果表明,该控制策略下,系统能够稳定运行,并网电流实现了精确控制,并且对电网电感具有良好的适应性。%The conventional proportional-integral (PI) control can not achieve the rapid and precise control of the grid-connected current because of its steady-state error. The introduction of grid inductor also has a non-negligible impact to damping strategy of the LCL filter when the PV system connects into the grid. To overcome the problems mentioned above, this paper presents a hybrid damping control strategy for single-phase grid-connected PV inverter with the control of PDFI. This strategy introduces proportional delay feedback integral (PDFI) control which adds a simple feedback circuit to the original PI control and can achieve the control of the grid current without steady-state error. The hybrid damping control is also analyzed which takes damping coefficient as the research object, and the impact of the grid inductor to damping strategy of the LCL filter is improved with addition of the hybrid damping control. The results of the theoretical analysis and the simulation both show that the proposed strategy has a great contribution to the control of the grid current and the steady operation of the system, and also has a good adaptability to the grid inductor.

  11. Smart Grid Enabled EVSE

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2015-01-12

    The combined team of GE Global Research, Federal Express, National Renewable Energy Laboratory, and Consolidated Edison has successfully achieved the established goals contained within the Department of Energy’s Smart Grid Capable Electric Vehicle Supply Equipment funding opportunity. The final program product, shown charging two vehicles in Figure 1, reduces by nearly 50% the total installed system cost of the electric vehicle supply equipment (EVSE) as well as enabling a host of new Smart Grid enabled features. These include bi-directional communications, load control, utility message exchange and transaction management information. Using the new charging system, Utilities or energy service providers will now be able to monitor transportation related electrical loads on their distribution networks, send load control commands or preferences to individual systems, and then see measured responses. Installation owners will be able to authorize usage of the stations, monitor operations, and optimally control their electricity consumption. These features and cost reductions have been developed through a total system design solution.

  12. Smart Grid Enabled EVSE

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2014-10-15

    The combined team of GE Global Research, Federal Express, National Renewable Energy Laboratory, and Consolidated Edison has successfully achieved the established goals contained within the Department of Energy’s Smart Grid Capable Electric Vehicle Supply Equipment funding opportunity. The final program product, shown charging two vehicles in Figure 1, reduces by nearly 50% the total installed system cost of the electric vehicle supply equipment (EVSE) as well as enabling a host of new Smart Grid enabled features. These include bi-directional communications, load control, utility message exchange and transaction management information. Using the new charging system, Utilities or energy service providers will now be able to monitor transportation related electrical loads on their distribution networks, send load control commands or preferences to individual systems, and then see measured responses. Installation owners will be able to authorize usage of the stations, monitor operations, and optimally control their electricity consumption. These features and cost reductions have been developed through a total system design solution.

  13. 3G POWER GRID SYSTEM

    OpenAIRE

    Saiyad Tausif Ali *; Gaurav Pawar; Pragati Rathi; Mandar Pathak

    2016-01-01

    3G Power grid system is dual side stream of electricity and automated construct information and distributed advanced energy delivery network. In this 3G Power grid system avoided the thermal and hydro sources of energy. By using the solar power and wind power energy will generate electricity according with the condition of nature. 3G Power grid system provides the facility of generating as well as marketing of electricity not only for the producers but also for consumers. By using megabytes o...

  14. Grid Integration of Robotic Telescopes

    CERN Document Server

    Breitling, F; Enke, H

    2008-01-01

    Robotic telescopes and grid technology have made significant progress in recent years. Both innovations offer important advantages over conventional technologies, particularly in combination with one another. Here, we introduce robotic telescopes used by the Astrophysical Institute Potsdam as ideal instruments for building a robotic telescope network. We also discuss the grid architecture and protocols facilitating the network integration that is being developed by the German AstroGrid-D project. Finally, we present three user interfaces employed for this purpose.

  15. Data Exchange in Grid Workflow

    Institute of Scientific and Technical Information of China (English)

    ZENG Hongwei; MIAO Huaikou

    2006-01-01

    In existing web services-based workflow, data exchanging across the web services is centralized, the workflow engine intermediates at each step of the application sequence.However, many grid applications, especially data intensive scientific applications, require exchanging large amount of data across the grid services.Having a central workfiow engine relay the data between the services would results in a bottleneck in these cases.This paper proposes a data exchange model for individual grid workflow and multiworkflows composition respectively.The model enables direct communication for large amounts of data between two grid services.To enable data to exchange among multiple workflows, the bridge data service is used.

  16. 谐波畸变电网下的单相同步旋转坐标系锁相环%Single-phase Synchronous Reference Frame Phase-locked Loop Under Harmonic Distorted Power Grid Condition

    Institute of Scientific and Technical Information of China (English)

    刘华吾; 孙永恒; 胡海兵; 邢岩

    2016-01-01

    锁相环技术是并网变流器的核心技术之一。针对传统单相同步旋转坐标系锁相环在畸变电网下锁相精度差的问题,提出一种基于离散傅里叶变换(DFT )的高精度锁相环技术。基于DFT的锁相技术的核心问题是如何准确获取电网频率,将DFT 和单相同步旋转坐标系锁相环相结合,利用DFT 的优异选择性滤波性能和相角变换性质,从畸变电网信号中准确提取基波和生成虚拟正交信号,在同步旋转坐标系提取电网频率,实现DFT 的频率自适应,最终无静差、高精度跟踪电网相位。仿真和实验结果表明,所提出的锁相环对电网电压的畸变谐波、直流偏置误差和电网频率脉动等有很好的适应性,在各种电网条件下,均能准确地跟踪电网电压相位,验证了该锁相方法的有效性和优越性。%The phase‐locked loop ( PLL) is a key aspect of grid‐tied converters . A new PLL technique based on discrete Fourier transform (DFT) is proposed to improve the performances of conventional synchronous reference frame PLLs under distorted power grid conditions . The major challenge of the category of DFT based synchronization methods is how to accurately obtain the grid frequency . For this problem , this paper combines the DFT with the single‐phase synchronous reference frame PLL . It utilizes the selective filtering and phase shifting properties of DFT to accurately extract the fundamental and generate its virtual orthogonal signals from the distorted grid . Then by transforming to the synchronous reference frame and properly control the q‐component , accurate synchronization with zero steady state errors is achieved . Besides , grid frequency variations are incorporated by adjusting the sampling period of DFT according to the estimated frequency . Simulation and experimental results show that the proposed DFT‐based PLL offers high harmonics immunity and DC component rejection

  17. Distributed computations in a dynamic, heterogeneous Grid environment

    Science.gov (United States)

    Dramlitsch, Thomas

    2003-06-01

    In order to face the rapidly increasing need for computational resources of various scientific and engineering applications one has to think of new ways to make more efficient use of the worlds current computational resources. In this respect, the growing speed of wide area networks made a new kind of distributed computing possible: Metacomputing or (distributed) Grid computing. This is a rather new and uncharted field in computational science. The rapidly increasing speed of networks even outperforms the average increase of processor speed: Processor speeds double on average each 18 month whereas network bandwidths double every 9 months. Due to this development of local and wide area networks Grid computing will certainly play a key role in the future of parallel computing. This type of distributed computing, however, distinguishes from the traditional parallel computing in many ways since it has to deal with many problems not occurring in classical parallel computing. Those problems are for example heterogeneity, authentication and slow networks to mention only a few. Some of those problems, e.g. the allocation of distributed resources along with the providing of information about these resources to the application have been already attacked by the Globus software. Unfortunately, as far as we know, hardly any application or middle-ware software takes advantage of this information, since most parallelizing algorithms for finite differencing codes are implicitly designed for single supercomputer or cluster execution. We show that although it is possible to apply classical parallelizing algorithms in a Grid environment, in most cases the observed efficiency of the executed code is very poor. In this work we are closing this gap. In our thesis, we will - show that an execution of classical parallel codes in Grid environments is possible but very slow - analyze this situation of bad performance, nail down bottlenecks in communication, remove unnecessary overhead and

  18. From the grid to the smart grid, topologically

    Science.gov (United States)

    Pagani, Giuliano Andrea; Aiello, Marco

    2016-05-01

    In its more visionary acceptation, the smart grid is a model of energy management in which the users are engaged in producing energy as well as consuming it, while having information systems fully aware of the energy demand-response of the network and of dynamically varying prices. A natural question is then: to make the smart grid a reality will the distribution grid have to be upgraded? We assume a positive answer to the question and we consider the lower layers of medium and low voltage to be the most affected by the change. In our previous work, we analyzed samples of the Dutch distribution grid (Pagani and Aiello, 2011) and we considered possible evolutions of these using synthetic topologies modeled after studies of complex systems in other technological domains (Pagani and Aiello, 2014). In this paper, we take an extra important step by defining a methodology for evolving any existing physical power grid to a good smart grid model, thus laying the foundations for a decision support system for utilities and governmental organizations. In doing so, we consider several possible evolution strategies and apply them to the Dutch distribution grid. We show how increasing connectivity is beneficial in realizing more efficient and reliable networks. Our proposal is topological in nature, enhanced with economic considerations of the costs of such evolutions in terms of cabling expenses and economic benefits of evolving the grid.

  19. Power grid complex network evolutions for the smart grid

    NARCIS (Netherlands)

    Pagani, Giuliano Andrea; Aiello, Marco

    2014-01-01

    The shift towards an energy grid dominated by prosumers (consumers and producers of energy) will inevitably have repercussions on the electricity distribution infrastructure. Today the grid is a hierarchical one delivering energy from large scale facilities to end-users. Tomorrow it will be a capill

  20. Power grid complex network evolutions for the smart grid

    NARCIS (Netherlands)

    Pagani, Giuliano Andrea; Aiello, Marco

    2014-01-01

    The shift towards an energy grid dominated by prosumers (consumers and producers of energy) will inevitably have repercussions on the electricity distribution infrastructure. Today the grid is a hierarchical one delivering energy from large scale facilities to end-users. Tomorrow it will be a capill

  1. Monthly Weather Review

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Supplements to the Monthly Weather Review publication. The Weather Bureau published the Monthly weather review Supplement irregularly from 1914 to 1949. The...

  2. Proposing Chinese Pharmacists Month

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ Dear Pharmacists: Today I would like to share with you about the American Pharmacists Month which is celebrated in October every year.This month-long observance is promoted by American Pharmacist Association.

  3. Knowledge Base Grid: A Generic Grid Architecture for Semantic Web

    Institute of Scientific and Technical Information of China (English)

    WU ZhaoHui(吴朝晖); CHEN HuaJun(陈华钧); XU JieFeng(徐杰锋)

    2003-01-01

    The emergence of semantic web will result in an enormous amount of knowledge base resources on the web. In this paper, a generic Knowledge Base Grid Architecture (KB-Grid)for building large-scale knowledge systems on the semantic web is presented. KB-Grid suggests a paradigm that emphasizes how to organize, discover, utilize, and manage web knowledge base resources. Four principal components are under development: a semantic browser for retrieving and browsing semantically enriched information, a knowledge server acting as the web container for knowledge, an ontology server for managing web ontologies, and a knowledge base directory server acting as the registry and catalog of KBs. Also a referential model of knowledge service and the mechanisms required for semantic communication within KB-Grid are defined. To verify the design rationale underlying the KB-Grid, an implementation of Traditional Chinese Medicine(TCM) is described.

  4. Grid Computing Making the Global Infrastructure a Reality

    CERN Document Server

    Fox, Geoffrey C; Hey, Anthony J G

    2003-01-01

    Grid computing is applying the resources of many computers in a network to a single problem at the same time Grid computing appears to be a promising trend for three reasons: (1) Its ability to make more cost-effective use of a given amount of computer resources, (2) As a way to solve problems that can't be approached without an enormous amount of computing power (3) Because it suggests that the resources of many computers can be cooperatively and perhaps synergistically harnessed and managed as a collaboration toward a common objective. A number of corporations, professional groups, university consortiums, and other groups have developed or are developing frameworks and software for managing grid computing projects. The European Community (EU) is sponsoring a project for a grid for high-energy physics, earth observation, and biology applications. In the United States, the National Technology Grid is prototyping a computational grid for infrastructure and an access grid for people. Sun Microsystems offers Gri...

  5. Simulation Analysis of Household Single-phase Grid-connected PV Power System%户用型单相光伏并网系统仿真分析

    Institute of Scientific and Technical Information of China (English)

    赵钢; 何军; 蒋辉

    2012-01-01

    针对3 kW光伏并网发电系统,详细分析了光伏电池的模型;采用扰动观察法实现最大功率点跟踪;选择电流内环电压外环的双环控制作为并网逆变器的控制策略,其中电流内环控制并网逆变器的输出电流跟随电网电压,电压外环控制直流母线电压稳定在400 V;将主动式频率偏移法运用于孤岛检测的算法控制,孤岛出现后2 s内迅速检测出孤岛并切断光伏逆变器。给出了基于MATLAB/Simulink的系统仿真模型。结果表明:光伏电池能很好地实现最大功率点跟踪,逆变后成功并网,在规定的时间内对孤岛做出判断,达到预期的设计目的。%In terms of a 3 kW grid-connected PV power system, this paper elaborates the model for PV cells. The ap- proach of perturbation and observation is utilized to track the maximum power point. A double loop control strategy is chosen for the grid inverter. Double loop control consists of an inner current loop and an outer voltage loop, where the inner current loop keeps the output of grid inverter following the network voltage and the outer voltage loop maintains the DC bus voltage at 400V. The application of active frequency shift method in the control algorithm of island detec- tion enables a quick detection of island (2s after its appearance) followed by the abscission of PV inverter. Then a system simulation model based on MATLAB/Simulink comes into being. The results show that PV cells can perfectly realize the track of maximum power point, as well as the successful interconnection after inverted, and can make right decision on island within regulated time. In brief, the expected design objective is fully attained.

  6. Grids Today, Clouds on the Horizon

    CERN Document Server

    Shiers, J

    2008-01-01

    By the time of CCP 2008, the largest scientific machine in the world -– the Large Hadron Collider -– had been cooled down as scheduled to its operational temperature of below 2 degrees Kelvin and injection tests were starting. Collisions of proton beams at 5 + 5 TeV were expected within one to two months of the initial tests, with data taking at design energy (7 + 7 TeV) foreseen for 2009. In order to process the data from this world machine, we have put our "Higgs in one basket" -– that of Grid computing. After many years of preparation, 2008 saw a final "Common Computing Readiness Challenge" (CCRC’08) -– aimed at demonstrating full readiness for 2008 data taking, processing and analysis. By definition, this relied on a world-wide production Grid infrastructure. But change – as always – is on the horizon. The current funding model for Grids – which in Europe has been through 3 generations of EGEE projects, together with related projects in other parts of the world, inc...

  7. Grids Today, Clouds on the Horizon

    CERN Document Server

    Shiers, J

    2008-01-01

    By the time of CCP 2008, the world’s largest scientific machine – the Large Hadron Collider – should have been cooled down to its operational temperature of below 20K and injection tests should have started. Collisions of proton beams at 5 + 5 TeV are expected within one to two months of the initial tests, with data taking at design energy (7 + 7 TeV) now foreseen for 2009. In order to process the data from this world machine, we have put our â€ワHiggs in one basket” – that of Grid computing. After many years of preparation, 2008 has seen a final â€ワCommon Computing Readiness Challenge” (CCRC’08) – aimed at demonstrating full readiness for 2008 data taking, processing and analysis. By definition, this relies on a world‐wide production Grid infrastructure. But change – as always – is on the horizon. The current funding model for Grids – which in Europe has been through 3 generations of EGEE projects, together with related projects in other part...

  8. The Open Science Grid

    Energy Technology Data Exchange (ETDEWEB)

    Pordes, Ruth; /Fermilab; Kramer, Bill; Olson, Doug; / /LBL, Berkeley; Livny, Miron; Roy, Alain; /Wisconsin U., Madison; Avery, Paul; /Florida U.; Blackburn, Kent; /Caltech; Wenaus, Torre; /Brookhaven; Wurthwein, Frank; /UC, San Diego; Gardner, Rob; Wilde, Mike; /Chicago U. /Indiana U.

    2007-06-01

    The Open Science Grid (OSG) provides a distributed facility where the Consortium members provide guaranteed and opportunistic access to shared computing and storage resources. OSG provides support for and evolution of the infrastructure through activities that cover operations, security, software, troubleshooting, addition of new capabilities, and support for existing and engagement with new communities. The OSG SciDAC-2 project provides specific activities to manage and evolve the distributed infrastructure and support its use. The innovative aspects of the project are the maintenance and performance of a collaborative (shared & common) petascale national facility over tens of autonomous computing sites, for many hundreds of users, transferring terabytes of data a day, executing tens of thousands of jobs a day, and providing robust and usable resources for scientific groups of all types and sizes. More information can be found at the OSG web site: www.opensciencegrid.org.

  9. The Open Science Grid

    CERN Document Server

    Pordes, Ruth; Olson, Doug; Livny, Miron; Roy, Alain; Avery, Paul; Blackburn, Kent; Wenaus, Torre; Wuerthwein, Frank K.; Gardner, Rob; Wilde, Mike; Blatecky, Alan; McGee, John; Quick, Rob

    2007-01-01

    The Open Science Grid (OSG) provides a distributed facility where the Consortium members provide guaranteed and opportunistic access to shared computing and storage resources. OSG provides support for and evolution of the infrastructure through activities that cover operations, security, software, troubleshooting, addition of new capabilities, and support for existing and engagement with new communities. The OSG SciDAC-2 project provides specific activities to manage and evolve the distributed infrastructure and support it's use. The innovative aspects of the project are the maintenance and performance of a collaborative (shared & common) petascale national facility over tens of autonomous computing sites, for many hundreds of users, transferring terabytes of data a day, executing tens of thousands of jobs a day, and providing robust and usable resources for scientific groups of all types and sizes. More information can be found at the OSG web site: www.opensciencegrid.org.

  10. The open science grid

    Energy Technology Data Exchange (ETDEWEB)

    Pordes, Ruth [Fermi National Accelerator Laboratory (United States); Petravick, Don [Fermi National Accelerator Laboratory (United States); Kramer, Bill [Lawrence Berkeley National Laboratory (United States); Olson, Doug [Lawrence Berkeley National Laboratory (United States); Livny, Miron [University of Wisconsin, Madison (United States); Roy, Alain [University of Wisconsin, Madison (United States); Avery, Paul [University of Florida (United States); Blackburn, Kent [California Institute of Technology (United States); Wenaus, Torre [Brookhaven National Laboratory (United States); Wuerthwein, Frank [University of California, San Diego (United States); Foster, Ian [University of Chicago (United States); Gardner, Rob [University of Chicago (United States); Wilde, Mike [University of Chicago (United States); Blatecky, Alan [Renaissance Computing Institute (United States); McGee, John [Renaissance Computing Institute (United States); Quick, Rob [Indiana University (United States)

    2007-07-15

    The Open Science Grid (OSG) provides a distributed facility where the Consortium members provide guaranteed and opportunistic access to shared computing and storage resources. OSG provides support for and evolution of the infrastructure through activities that cover operations, security, software, troubleshooting, addition of new capabilities, and support for existing and engagement with new communities. The OSG SciDAC-2 project provides specific activities to manage and evolve the distributed infrastructure and support it's use. The innovative aspects of the project are the maintenance and performance of a collaborative (shared and common) petascale national facility over tens of autonomous computing sites, for many hundreds of users, transferring terabytes of data a day, executing tens of thousands of jobs a day, and providing robust and usable resources for scientific groups of all types and sizes. More information can be found at the OSG web site: www.opensciencegrid.org.

  11. DIRAC: a community grid solution

    Energy Technology Data Exchange (ETDEWEB)

    Tsaregorodtsev, A [Centre de Physique des Particules de Marseille, 163 Av de Luminy Case 902 13288 Marseille (France); Bargiotti, M; Castellani, G; Charpentier, P; Closier, J; Paterson, S; Santinelli, R [CERN CH-1211 Geneve 23 (Switzerland); Brook, N [H. H. Wills Physics Laboratory, Royal Fort, Tyndal Avenue, Bristol BS8 1TL (United Kingdom); Ramo, A C; Diaz, R G [University of Barcelona, Diagonal 647, ES-08028 Barcelona (Spain); Cioffi, C [University of Oxford, 1, Keble Road, Oxford OX1 3NP (United Kingdom); Kuznetsov, G; Nandakumar, R [Rutherford Appleton Laboratory, Chilton, Didcot Oxon. OX11 0QX (United Kingdom); Li, Y Y [University of Cambridge, Wilberforce Road, Cambridge CB3 OWA (United Kingdom); Miguelez, M S [University of Santiago de Compostela, Campus Universitario Sur, ES-15706 Santiago de Compostela (Spain); Jimenez, S G [University Rovira i Virgili, Campus Sescelades, Avinguda dels Paisos Catalans, 26 Tarragona (Spain); Smith, A C, E-mail: atsareg@in2p3.fr

    2008-07-15

    The DIRAC system was developed in order to provide a complete solution for using the distributed computing resources of the LHCb experiment at CERN for data production and analysis. It allows a concurrent use of over 10K CPUs and 10M file replicas distributed over many tens of sites. The sites can be part of a Computing Grid such as WLCG or standalone computing clusters all integrated in a single management structure. DIRAC is a generic system with the LHCb specific functionality incorporated through a number of plug-in modules. It can be easily adapted to the needs of other communities. Special attention is paid to the resilience of the DIRAC components to allow an efficient use of non-reliable resources. The DIRAC production management components provide a framework for building highly automated data production systems including data distribution and data driven workload scheduling. In this paper we give an overview of the DIRAC system architecture and design choices. We show how different components are put together to compose an integrated data processing system including all the aspects of the LHCb experiment - from the MC production and raw data reconstruction to the final user analysis.

  12. DIRAC: a community grid solution

    CERN Document Server

    Tsaregorodtsev, A; Brook, N; Ramo, A C; Castellani, G; Charpentier, P; Cioffi, C; Closier, J; Díaz, R G; Kuznetsov, G; Li, Y Y; Nandakumar, R; Paterson, S; Santinelli, R; Smith, A C; Miguelez, M S; Jimenez, S G

    2008-01-01

    The DIRAC system was developed in order to provide a complete solution for using the distributed computing resources of the LHCb experiment at CERN for data production and analysis. It allows a concurrent use of over 10K CPUs and 10M file replicas distributed over many tens of sites. The sites can be part of a Computing Grid such as WLCG or standalone computing clusters all integrated in a single management structure. DIRAC is a generic system with the LHCb specific functionality incorporated through a number of plug-in modules. It can be easily adapted to the needs of other communities. Special attention is paid to the resilience of the DIRAC components to allow an efficient use of non-reliable resources. The DIRAC production management components provide a framework for building highly automated data production systems including data distribution and data driven workload scheduling. In this paper we give an overview of the DIRAC system architecture and design choices. We show how different components are pu...

  13. Monitoring of Grid scientific workflows

    NARCIS (Netherlands)

    Balis, B.; Bubak, M.; Łabno, B.

    2008-01-01

    Scientific workflows are a means of conducting in silico experiments in modern computing infrastructures for e-Science, often built on top of Grids. Monitoring of Grid scientific workflows is essential not only for performance analysis but also to collect provenance data and gather feedback useful

  14. Monitoring of Grid scientific workflows

    NARCIS (Netherlands)

    Balis, B.; Bubak, M.; Łabno, B.

    2008-01-01

    Scientific workflows are a means of conducting in silico experiments in modern computing infrastructures for e-Science, often built on top of Grids. Monitoring of Grid scientific workflows is essential not only for performance analysis but also to collect provenance data and gather feedback useful i

  15. Smart Grid Communication Middleware Comparison

    DEFF Research Database (Denmark)

    Petersen, Bo Søborg; Bindner, Henrik W.; Poulsen, Bjarne

    2017-01-01

    are possible by their performance, which is limited by the middleware characteristics, primarily interchangeable serialization and the Publish-Subscribe messaging pattern. The earlier paper “Smart Grid Serialization Comparison” (Petersen et al. 2017) aids in the choice of serialization, which has a big impact...... the strongest candidates for Smart Grid distributed control, but WAMP should also be considered in the future....

  16. On Robustness of Power Grids

    NARCIS (Netherlands)

    Koç, Y.

    2015-01-01

    Current and future trends in environmental, economical, and human-caused factors (such as power demand growth, over-ageing of assets in power grids, and extreme weather conditions) challenge power grid robustness in the near future, necessitating research to better analyse and understand the notion

  17. GRID INFORMATION SECURITY FUNCTIONAL REQUIREMENT

    Directory of Open Access Journals (Sweden)

    Amy Poh Ai Ling

    2011-07-01

    Full Text Available This paper describes the background of smart information infrastructure and the needs for smart grid information security. It introduces the conceptual analysis to the methodology with the application ofhermeneutic circle and information security functional requirement identification. Information security for the grid market cover matters includes automation and communications industry that affects the operation of electric power systems and the functioning of the utilities that manage them and its awareness of this information infrastructure has become critical to the reliability of the power system. Community benefits from of cost savings, flexibility and deployment along with the establishment of wireless communications. However, concern revolves around the security protections for easily accessible devices such as the smart meter and the related communications hardware. On the other hand, the changing points between traditional versus smart grid networking trend and the information security importance on the communication field reflects the criticality of grid information security functional requirement identification. The goal of this paper is to identify the functional requirement and relate its significance addresses to the consumer requirement of an information security of a smart grid. Vulnerabilities may bring forth possibility for an attacker to penetrate a network, make headway admission to control software, alter it to load conditions that destabilize the grid in unpredictable ways. Focusing on the grid information security functional requirement is stepping ahead in developing consumer trust and satisfaction towardsmart grid completeness.

  18. Decentralized power supply for a single-family house. Power supply by a photovoltaic system, battery and connection to the grid; Dezentrale Stromversorgung eines Einfamilienhauses. Stromversorgung mit Photovoltaik, Batterie und Netzanschluss

    Energy Technology Data Exchange (ETDEWEB)

    Staudacher, Thomas; Eller, Sebastian [Forschungsstelle fuer Energiewirtschaft e.V. (FfE), Muenchen (Germany)

    2012-07-01

    In view of increasing electricity costs and the remuneration by the EEG, systematic measures to enhance the own consumption of photovoltaic power increasingly come to the fore of public discussion - in spite of recent reductions of the remunerations by the EEG. In order to increase own consumption and the rate of self-sufficiency, the so-called own coverage, the first commercial battery storage systems are available. The Research Center for Energy Economics (Forschungsstelle fuer Energiewirtschaft e.V., FfE) developed a model that simulates a decentralized domestic power supply by a photovoltaic system, battery and connection to the grid. This simulation model enables the determination of the rate of own consumption and own coverage for different constellations of the power supply of a household. (orig.)

  19. The Study of Smart Grid Knowledge Visualization Key Technologies

    Directory of Open Access Journals (Sweden)

    Jia Yan

    2013-07-01

    Full Text Available To solve the problems of knowledge visualization for smart grid, such as single manifestations, low-efficient use and not high model reuse rate, a general three-dimensional smart grid knowledge visualization model was presented in this paper. First, the construction method of grid device models based on knowledge-based reasoning was given. Then, the grid visual scene building method was proposed. This included rapid scene organization strategy, and exploration on the storage and re-use mechanism of three-dimensional visualization scene. Moreover, collision detection using swarm intelligence and bionic computing to solve its existing problems. Finally, The feasibility and practicality of the method was verified by a developed intelligent power virtual drill platform based on JME (JMonkeyEngine.    

  20. Low-voltage grid-connection of photovoltaic power systems

    Energy Technology Data Exchange (ETDEWEB)

    Collinson, A.; Thornycroft, J.

    1999-07-01

    This report summarises the results of a project aimed at developing technical guidelines concerning grid connected photovoltaic (PV) inverter generators which are to be published in draft form as the {sup U}K Technical Guidelines for Inverter Connected Single Phase Photovoltaic (PV) Generators up to 5kVA{sup .} The background to the use of PV in the UK is traced, and the technical criteria for electrical integration of PV systems, and UK guidelines for grid connected PV systems are examined. The findings of the working group of the International Energy Agency (IEA) Implementing Agreement on Photovoltaic Power Systems are also presented in this report. Appendices discuss the UK technical guidelines, the IEA Task V activities,, utility aspects of grid-connected PV systems, and demonstration tests on grid-connected PV systems, and lists Task V reports.

  1. Application of the grid computing technology in electrical energy engineering

    Energy Technology Data Exchange (ETDEWEB)

    Al-Khannak, R. [South Westphalia Univ. of Applied Sciences, Soest (Germany)

    2007-07-01

    The need for reliable, powerful, and clean power generation in power systems is becoming more importance. This need requires geographically-distributed power systems to be integrated as a single entity where among the main features of this integration are large data base and computing intensive. Hence the current power systems are not able to handle this huge datasets required for that integration, Grid Computing is a gateway to virtual storage media and processing power. This paper describes the research work on why grid computing is needed for power systems, what are the major challenges and problem to implement grid computing into power systems, and how grid computing can be utilized to fulfil the requirement for efficient power generation. (orig.)

  2. PV GRID Advisory Paper. Consultation version: key recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Barth, Bianca; Concas, Giorgia; Cossent, Rafael; Franz, Oliver; Frias, Pablo; Hermes, Roland; Lama, Riccardo; Loew, Holger; Mateo, Carlos; Rekinger, Manoel; Sonvilla, Paolo Michele; Vandenbergh, Michel

    2014-01-15

    PV GRID is a transnational collaborative effort under the umbrella of the Intelligent Energy Europe programme. The main project goal is to enhance photovoltaic (PV) hosting capacity in distribution grids while overcoming regulatory and normative barriers hampering the application of available technical solutions. The European PV GRID advisory paper aims at providing an overview of the issues and barriers that need to be addressed in order to enhance the distribution grid hosting capacity for PV and other distributed generation (DG).To this purpose, barriers are classified as either cross-cutting challenges or specific barriers, depending on whether they have an overarching, system-wide character or rather focus on one single issue such as curtailment, self-consumption or storage. Finally, a set of preliminary recommendations on how to overcome these issues is presented, allowing for the implementation of the identified technical solutions.

  3. FUZZY LOGIC CONTROLLER OF DFIG TO RIDE THROUGH RECURRING GRID FAULTS

    Directory of Open Access Journals (Sweden)

    Mani Kumar Gutti

    2016-09-01

    Full Text Available The penetration of Wind Turbine Systems (WTS is increasing in recent years. The new grid codes saying that the WTS must remain connected to utility grid at voltages below rated and also under recurring grid faults. The rotor side crowbar with vector control can ride through single grid fault. The rotor side crowbar fails to Ride Through recurring grid faults due to large electromagnetic torque fluctuations. This may affect mechanical system which leads to damage the gear box of WTS. This paper presents fuzzy logic control to investigate Doubly Fed Induction Generator (DFIG WTS to fault ride through (FRT recurring symmetrical grid faults. A rotor natural current is injected into the rotor circuit during voltage recovery under grid faults. By this the decay time of stator natural flux can be minimized. This will suppress the electromagnetic torque fluctuations and improves the mechanical system. The system is modeled by using MATLAB software.

  4. gCube Grid services

    CERN Document Server

    Andrade, Pedro

    2008-01-01

    gCube is a service-based framework for eScience applications requiring collaboratory, on-demand, and intensive information processing. It provides to these communities Virtual Research Environments (VREs) to support their activities. gCube is build on top of standard technologies for computational Grids, namely the gLite middleware. The software was produced by the DILIGENT project and will continue to be supported and further developed by the D4Science project. gCube reflects within its name a three-sided interpretation of the Grid vision of resource sharing: sharing of computational resources, sharing of structured data, and sharing of application services. As such, gCube embodies the defining characteristics of computational Grids, data Grids, and virtual data Grids. Precisely, it builds on gLite middleware for managing distributed computations and unstructured data, includes dedicated services for managing data and metadata, provides services for distributed information retrieval, allows the orchestration...

  5. The DataGrid Project

    CERN Document Server

    Ruggieri, F

    2001-01-01

    An overview of the objectives and status of the DataGrid Project is presented, together with a brief introduction to the Grid metaphor and some references to the Grid activities and initiatives related to DataGrid. High energy physics experiments have always requested state of the art computing facilities to efficiently perform several computing activities related with the handling of large amounts of data and fairly large computing resources. Some of the ideas born inside the community to enhance the user friendliness of all the steps in the computing chain have been, sometimes, successfully applied also in other contexts: one bright example is the World Wide Web. The LHC computing challenge has triggered inside the high energy physics community, the start of the DataGrid Project. The objective of the project is to enable next generation scientific exploration requiring intensive computation and analysis of shared large-scale databases. (12 refs).

  6. CMS Requirements for the Grid

    Institute of Scientific and Technical Information of China (English)

    K.Holtman; J.Amundson; 等

    2001-01-01

    CMS physicists need to seamlessly access their experimental data and results,independent of location and storage medium,in order to focus on the exploration for the new physics signals arther than the complexities of worldwide data management .In order to achieve this goal,CMS has adopted a tiered worldwide computing model which will incorporate emerging Grid technology.CMS has started to use Grid tools for data processing,replication and migration,Important Grid components are expected to be delivered by the Data Grid projects.like projects,CMS has created a set of long-term requirements to the Grid projects.These requirements are presented and discussed.

  7. Towards trusted volunteer grid environments

    CERN Document Server

    Khemakhem, Maher; University, Sousse; Tunisia,; University, Manouba; Tunisia),; 10.5121/ijcnc.2010.2207

    2010-01-01

    Intensive experiences show and confirm that grid environments can be considered as the most promising way to solve several kinds of problems relating either to cooperative work especially where involved collaborators are dispersed geographically or to some very greedy applications which require enough power of computing or/and storage. Such environments can be classified into two categories; first, dedicated grids where the federated computers are solely devoted to a specific work through its end. Second, Volunteer grids where federated computers are not completely devoted to a specific work but instead they can be randomly and intermittently used, at the same time, for any other purpose or they can be connected or disconnected at will by their owners without any prior notification. Each category of grids includes surely several advantages and disadvantages; nevertheless, we think that volunteer grids are very promising and more convenient especially to build a general multipurpose distributed scalable enviro...

  8. On Multigrid for Overlapping Grids

    Energy Technology Data Exchange (ETDEWEB)

    Henshaw, W

    2004-01-13

    The solution of elliptic partial differential equations on composite overlapping grids using multigrid is discussed. An approach is described that provides a fast and memory efficient scheme for the solution of boundary value problems in complex geometries. The key aspects of the new scheme are an automatic coarse grid generation algorithm, an adaptive smoothing technique for adjusting residuals on different component grids, and the use of local smoothing near interpolation boundaries. Other important features include optimizations for Cartesian component grids, the use of over-relaxed Red-Black smoothers and the generation of coarse grid operators through Galerkin averaging. Numerical results in two and three dimensions show that very good multigrid convergence rates can be obtained for both Dirichlet and Neumann/mixed boundary conditions. A comparison to Krylov based solvers shows that the multigrid solver can be much faster and require significantly less memory.

  9. FIRAS wire grid characterization techniques

    Science.gov (United States)

    Barney, Richard D.; Magner, Thomas J.

    1989-01-01

    Characterization techniques used to verify the quality and spectral performance of the large freestanding wire grid polarizing beamsplitters and input/output polarizers used in the Far Infrared Absolute Spectrophotometer (FIRAS) are presented. The clear aperture of these grids is lined with 20.8 micron diameter gold coated tungsten wire, spaced 33 microns apart. The grid characteristics measured throughout fabrication and space flight qualification are the center to center wire spacing and wire plane flatness. Ideally, the wire grids should produce coherent wavefronts with equal reflectance and transmittance properties. When the spacing is inconsistent, these wavefront intensities are unequal, thus decreasing the efficiency of the grids and reducing the output signal of the FIRAS. The magnitude of the output interferogram is also reduced by incoherence in the interfering wave fronts caused by uneven flatness.

  10. From the Grid to the Smart Grid, Topologically

    CERN Document Server

    Pagani, Giuliano Andrea

    2013-01-01

    The Smart Grid is not just about the digitalization of the Power Grid. In its more visionary acceptation, it is a model of energy management in which the users are engaged in producing energy as well as consuming it, while having information systems fully aware of the energy demand-response of the network and of dynamically varying prices. A natural question is then: to make the Smart Grid a reality will the Distribution Grid have to be updated? We assume a positive answer to the question and we consider the lower layers of Medium and Low Voltage to be the most affected by the change. In our previous work, we have analyzed samples of the Dutch Distribution Grid in our previous work and we have considered possible evolutions of these using synthetic topologies modeled after studies of complex systems in other technological domains in another previous work. In this paper, we take an extra important further step by defining a methodology for evolving any existing physical Power Grid to a good Smart Grid model th...

  11. A Stationary Reference Frame Grid Synchronization System for Three-Phase Grid-Connected Power Converters Under Adverse Grid Conditions

    DEFF Research Database (Denmark)

    Rodríguez, P.; Luna, A.; Muñoz-Aguilar, R. S.

    2012-01-01

    Grid synchronization algorithms are of great importance in the control of grid-connected power converters, as fast and accurate detection of the grid voltage parameters is crucial in order to implement stable control strategies under generic grid conditions. This paper presents a new grid...... of the instantaneous symmetrical components of the grid voltage under unbalanced and distorted grid conditions. This paper analyzes the performance of the proposed synchronization method including different design issues. Moreover, the behavior of the method for synchronizing with highly unbalanced grid is proven...

  12. BSCW Unstructured Grids - VGRID software FINAL

    Data.gov (United States)

    National Aeronautics and Space Administration — These grids were constructed using VGRID software from NASA Langley. The grids designed for node based (labeled 'nc') and cell-centered solvers are supplied. Grids...

  13. Sensing and Measurement Architecture for Grid Modernization

    Energy Technology Data Exchange (ETDEWEB)

    Taft, Jeffrey D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); De Martini, Paul [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2016-02-01

    This paper addresses architecture for grid sensor networks, with primary emphasis on distribution grids. It describes a forward-looking view of sensor network architecture for advanced distribution grids, and discusses key regulatory, financial, and planning issues.

  14. SMART BUILDINGS: Meet The Smart Grid

    National Research Council Canada - National Science Library

    Paul Ehrlich; Ira Goldschmidt

    2009-01-01

    The Smart Grid concept is to develop a more intelligent and integrated electrical transmission infrastructure including use of smart two-way meters, connections of regional grids, and new grid management tools...

  15. Smart grid security innovative solutions for a modernized grid

    CERN Document Server

    Skopik, Florian

    2015-01-01

    The Smart Grid security ecosystem is complex and multi-disciplinary, and relatively under-researched compared to the traditional information and network security disciplines. While the Smart Grid has provided increased efficiencies in monitoring power usage, directing power supplies to serve peak power needs and improving efficiency of power delivery, the Smart Grid has also opened the way for information security breaches and other types of security breaches. Potential threats range from meter manipulation to directed, high-impact attacks on critical infrastructure that could bring down regi

  16. Statistical Computations with AstroGrid and the Grid

    CERN Document Server

    Nichol, R C; Miller, C J; Genovese, C; Wasserman, L; Bryan, B; Gray, A; Schneider, J; Moore, A W; Nichol, Robert C; Smith, Garry; Miller, Christopher J; Genovese, Chris; Wasserman, Larry; Bryan, Brent; Gray, Alexander; Schneider, Jeff; Moore, Andrew W

    2005-01-01

    We outline our first steps towards marrying two new and emerging technologies; the Virtual Observatory (e.g, AstroGrid) and the computational grid. We discuss the construction of VOTechBroker, which is a modular software tool designed to abstract the tasks of submission and management of a large number of computational jobs to a distributed computer system. The broker will also interact with the AstroGrid workflow and MySpace environments. We present our planned usage of the VOTechBroker in computing a huge number of n-point correlation functions from the SDSS, as well as fitting over a million CMBfast models to the WMAP data.

  17. GRID superscalar: a programming model for the Grid

    OpenAIRE

    2009-01-01

    Durant els darrers anys el Grid ha sorgit com una nova plataforma per la computació distribuïda. La tecnologia Gris permet unir diferents recursos de diferents dominis administratius i formar un superordinador virtual amb tots ells. Molts grups de recerca han dedicat els seus esforços a desenvolupar un conjunt de serveis bàsics per oferir un middleware de Grid: una capa que permet l'ús del Grid. De tota manera, utilitzar aquests serveis no és una tasca fácil per molts usuaris finals, cosa que...

  18. Comparison of ventilation-perfusion single-photon emission computed tomography (V/Q SPECT) versus dual-energy CT perfusion and angiography (DECT) after 6 months of pulmonary embolism (PE) treatment

    Energy Technology Data Exchange (ETDEWEB)

    Meysman, M., E-mail: marc.meysman@uzbrussel.be [Respiratory Division, Department of Medicine, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Brussels (Belgium); Everaert, H., E-mail: nucgeth@gmail.com [Department of Nuclear Medicine, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Brussels (Belgium); Buls, N., E-mail: nico.buls@uzbrussel.be [Department of Radiology, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Brussels (Belgium); Nieboer, K., E-mail: koenraad.nieboer@uzbrussel.be [Department of Radiology, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Brussels (Belgium); Mey, J. de, E-mail: Johan.deMey@uzbrussel.be [Department of Radiology, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel (VUB), Brussels (Belgium)

    2015-09-15

    Highlights: • Incomplete resolution of pulmonary emboli occurs frequently. • Residual V/Q-SPECT defects correspond in the majority of cases with defects seen on DECT. • Some (11.1%) defects on V/Q-SPECT are not present on comparable DECT images. - Abstract: Background: The natural evolution of treated symptomatic pulmonary embolism shows often incomplete resolution of pulmonary thrombi. The prevalence of perfusion defects depend on the image modality used. This study directly compares V/Q SPECT with DECT. Methods: A single-center prospective observational cohort study of patients with intermediate risk PE, reassessed at the end of treatment with V/Q SPECT. Abnormal V/Q SPECT images were compared with DECT. Results: We compared DECT en V/Q SPECT in 28 consecutive patients with persistent V/Q mismatch on V/Q SPECT, 13 men and 15 woman, mean age 60 (+17), range 23–82 year. One patient was excluded from the final analysis due to inferior quality DECT. In 18/27 (66.7%) the results were concordant between CTPA (persistent embolus visible), DECT (segmentary defects on iodine map) and V/Q SPECT (segmentary ventilation–perfusion mismatch). In 3/18 (11.1% of the total group) the partialy matched V/Q SPECT defect could be explained on DECT lung images by lung infarction. In 6/27 (22.1%) only hypoperfusion was seen on DECT iodine map. In 3/27 (11.1%) results were discordant between V/Q SPECT and DECT images. Conclusion: Six months after diagnosis of first or recurrent PE, residual pulmonary perfusion-defects encountered on V/Q-SPECT corresponds in the majority of patients with chronic thromboembolic disease seen on DECT. In 22.1% of patients V/Q SPECT mismatch only corresponds with hypoperfusion on iodine map DECT scan. Some (11.1%) of the chronic thromboembolic lesions seen on V/Q SPECT can not be explained by DECT results.

  19. Automatic computation of Euler-marching and subsonic grids for wing-fuselage configurations

    Science.gov (United States)

    Barger, Raymond L.; Adams, Mary S.; Krishnan, Ramki R.

    1994-01-01

    Algebraic procedures are described for the automatic generation of structured, single-block flow computation grids for relatively simple configurations (wing, fuselage, and fin). For supersonic flows, a quasi two-dimensional grid for Euler-marching codes is developed, and some sample results in graphical form are included. A type of grid for subsonic flow calculation is also described. The techniques are algebraic and are based on a generalization of the method of transfinite interpolation.

  20. Control of Doubly-Fed Induction Generator to Ride-Through Recurring Grid Faults

    DEFF Research Database (Denmark)

    Chen, Wenjie; Xu, Dehong; Zhu, Nan;

    2016-01-01

    The wind turbine system (WTS) is required to ride-through recurring grid faults by the new grid codes. Under single grid faults, the fault ride-through (FRT) strategy with rotor-side crowbar is normally used for the doubly-fed induction generator (DFIG) WTS. However, under recurring faults, larger.......5-MW DFIG model and by experiments on a 30-kW DFIG test system....

  1. Performance Of Microturbine Generation System in Grid Connected and Islanding Modes of Operation

    OpenAIRE

    Gaonkar, Dattatraya N.

    2010-01-01

    The Distributed generation based on microturbine technology is new and a fast growing business. These DG systems are quickly becoming an energy management solution that saves money, resources, and environment in one compact and scalable package- be it stationary or mobile, remote or interconnected with the utility grid. In this thesis the MTG system model suitable for grid connected and islanding operation has been presented.The detailed modeling of a single-shaft MTG system suitable for grid...

  2. Experimental Evaluation of Grid Support Enabled PV Inverter Response to Abnormal Grid Conditions: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Austin; Martin, Gregory; Hurtt, James

    2017-05-08

    As revised interconnection standards for grid-tied photovoltaic (PV) inverters address new advanced grid support functions (GSFs), there is increasing interest in inverter performance in the case of abnormal grid conditions. The growth of GSF-enabled inverters has outpaced the industry standards that define their operation, although recently published updates to UL1741 with Supplement SA define test conditions for GSFs such as volt-var control, frequency-watt control, and volt-age/frequency ride-through, among others. A comparative experimental evaluation has been completed on four commercially available, three-phase PV inverters in the 24.0-39.8 kVA power range on their GSF capability and the effect on abnormal grid condition response. This study examines the impact particular GSF implementations have on run-on times during islanding conditions, peak voltages in load rejection overvoltage scenarios, and peak currents during single-phase and three-phase fault events for individual inverters. This report reviews comparative test data, which shows that GSFs have little impact on the metrics of interest in most tests cases.

  3. Energy Conservation In Computational Grids

    Directory of Open Access Journals (Sweden)

    Monika Yadav

    2012-07-01

    Full Text Available With the increasing development of high-speed wide-area networks and powerful though low cost computational resources, grid computing has emerged as an attractive computing paradigm.With recent advances in computing, the scope of grid computing has been expanded to include mobile and pervasive devices. Grids have become one of the highest consumers of energy. High performance computing is achieved at the cost of energy consumption. Increasing the performance of computer systems requires increasing number of resources which leads to higher power consumption and it creates negative impact on environment. Idle sites in grid are direct sources of energy waste. Saving energy causes twodirect advantages: financial and environmental cost reduction and sustainability. With the Grid becoming a viable high-performance alternative to the traditional supercomputing environment, various aspects of Grid resource utilization which can help in energy conservation are gaining significance. In this paper we explore the possibility of reduction in energy consumption of a grid of heterogeneous computers by making use of different power states of cpu.

  4. A Back-Stepping Sliding Mode Control Strategy for Single-Phase Photovoltaic Grid-Connected Inverter%单相光伏并网逆变器的反步滑模控制策略

    Institute of Scientific and Technical Information of China (English)

    游国栋; 李继生; 侯勇; 赵春东

    2015-01-01

    Since the photovoltaic (PV) grid-connected inverter system is easy to be affected by such factors as external interference and the uncertainty of its system parameters, taking the output voltage of filter capacitor and its derivative as state variables and integrating the back-stepping method with sliding mode control, a back-stepping sliding mode control based control strategy for PV grid-connected inverter is proposed, and the feedback control law for the inverter under parameter uncertainty and external interference is derived. To achieve the global maximum power point (MPP) of PV array, an improved particle swarm optimization (PSO) algorithm based maximum power point tracking (MPPT) method is put forward, and the duty ratio is divided into two parts for the initialization, thus a linear relation between the operational power of PV array and the duty ratio is established. The effectiveness of the proposed control strategy is validated by both results of simulation and experiments.%为了克服光伏并网逆变系统受外界干扰和系统参数的不确定性等多种因素的干扰,以逆变器的输出滤波电容电压及其导数为状态变量,将反步法和滑模控制相结合,提出了基于反步滑模控制的光伏并网逆变器控制策略。推导了具有参数不确定和外界干扰情况下的逆变器的反馈控制律。为了获取光伏阵列的全局最大功率点(maximum power point, MPP),提出了一种基于改进粒子群优化算法(particle swarm optimization,PSO)的最大功率点跟踪(maximum power point tracking,MPPT)方法,将占空比分为两部分进行初始化,建立了光伏阵列运行功率与占空比之间的线性关系。仿真和试验结果验证了所提控制策略的有效性。

  5. An electrostatic analog for generating cascade grids

    Science.gov (United States)

    Adamczyk, J. J.

    1980-01-01

    Accurate and efficient numerical simulation of flows through turbomachinery blade rows depends on the topology of the computational grids. These grids must reflect the periodic nature of turbomachinery blade row geometries and conform to the blade shapes. Three types of grids can be generated that meet these minimal requirements: through-flow grids, O-type grids, and C-type grids. A procedure which can be used to generate all three types of grids is presented. The resulting grids are orthogonal and can be stretched to capture the essential physics of the flow. A discussion is also presented detailing the extension of the generation procedure to three dimensional geometries.

  6. First scientific results from the Estonian Grid

    CERN Document Server

    Hektor, A; Kadastik, M; Skaburskas, K; Teder, H; Hektor, Andi; Anton, Lauri; Kadastik, Mario; Skaburskas, Konstantin; Teder, Hardi

    2004-01-01

    We present first scientific results, technical details and recent developments in the Estonian Grid. Ideas and concepts behind Grid technology are described. We mention some most crucial parts of a Grid system, as well as some unique possibilities in the Estonian situation. Scientific applications currently running on Estonian Grid are listed. We discuss the first scientific computations and results the Estonian Grid. The computations show that the middleware is well chosen and the Estonian Grid has remarkable stability and scalability. The authors present the collected results and experiences of the development of the Estonian Grid and add some ideas of the near future of the Estonian Grid.

  7. National transmission grid study

    Energy Technology Data Exchange (ETDEWEB)

    Abraham, Spencer [USDOE Office of the Secretary of Energy, Washington, DC (United States)

    2003-05-31

    The National Energy Policy Plan directed the U.S. Department of Energy (DOE) to conduct a study to examine the benefits of establishing a national electricity transmission grid and to identify transmission bottlenecks and measures to address them. DOE began by conducting an independent analysis of U.S. electricity markets and identifying transmission system bottlenecks using DOE’s Policy Office Electricity Modeling System (POEMS). DOE’s analysis, presented in Section 2, confirms the central role of the nation’s transmission system in lowering costs to consumers through increased trade. More importantly, DOE’s analysis also confirms the results of previous studies, which show that transmission bottlenecks and related transmission system market practices are adding hundreds of millions of dollars to consumers’ electricity bills each year. A more detailed technical overview of the use of POEMS is provided in Appendix A. DOE led an extensive, open, public input process and heard a wide range of comments and recommendations that have all been considered.1 More than 150 participants registered for three public workshops held in Detroit, MI (September 24, 2001); Atlanta, GA (September 26, 2001); and Phoenix, AZ (September 28, 2001).

  8. The Grid Resource Broker, A Ubiquitous Grid Computing Framework

    Directory of Open Access Journals (Sweden)

    Giovanni Aloisio

    2002-01-01

    Full Text Available Portals to computational/data grids provide the scientific community with a friendly environment in order to solve large-scale computational problems. The Grid Resource Broker (GRB is a grid portal that allows trusted users to create and handle computational/data grids on the fly exploiting a simple and friendly web-based GUI. GRB provides location-transparent secure access to Globus services, automatic discovery of resources matching the user's criteria, selection and scheduling on behalf of the user. Moreover, users are not required to learn Globus and they do not need to write specialized code or to rewrite their existing legacy codes. We describe GRB architecture, its components and current GRB features addressing the main differences between our approach and related work in the area.

  9. Profitability of smart grid solutions applied in power grid

    Directory of Open Access Journals (Sweden)

    Katić Nenad A.

    2016-01-01

    Full Text Available The idea of a Smart Grid solution has been developing for years, as complete solution for a power utility, consisting of different advanced technologies aimed at improving of the efficiency of operation. The trend of implementing various smart systems continues, e.g. Energy Management Systems, Grid Automation Systems, Advanced Metering Infrastructure, Smart power equipment, Distributed Energy Resources, Demand Response systems, etc. Futhermore, emerging technologies, such as energy storages, electrical vehicles or distributed generators, become integrated in distribution networks and systems. Nowadays, the idea of a Smart Grid solution becomes more realistic by full integration of all advanced operation technologies (OT within IT environment, providing the complete digitalization of an Utility (IT/OT integration. The overview of smart grid solutions, estimation of investments, operation costs and possible benefits are presented in this article, with discusison about profitability of such systems.

  10. Buildings-to-Grid Technical Opportunities: From the Grid Perspective

    Energy Technology Data Exchange (ETDEWEB)

    Kropski, Ben [National Renewable Energy Lab. (NREL), Golden, CO (United States); Pratt, Rob [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-03-28

    This paper outlines the nature of the power grid, lists challenges and barriers to the implementation of a transactive energy ecosystem, and provides concept solutions to current technological impediments.

  11. Hierarchical Control for Smart Grids

    DEFF Research Database (Denmark)

    Trangbæk, K; Bendtsen, Jan Dimon; Stoustrup, Jakob

    2011-01-01

    This paper deals with hierarchical model predictive control (MPC) of smart grid systems. The design consists of a high level MPC controller, a second level of so-called aggregators, which reduces the computational and communication-related load on the high-level control, and a lower level...... of autonomous consumers. The control system is tasked with balancing electric power production and consumption within the smart grid, and makes active use of the flexibility of a large number of power producing and/or power consuming units. The objective is to accommodate the load variation on the grid, arising...

  12. SDPG: Spatial Data Processing Grid

    Institute of Scientific and Technical Information of China (English)

    XIAO Nong(肖侬); FUV Wei(付伟)

    2003-01-01

    Spatial applications will gain high complexity as the volume of spatial data increases rapidly. A suitable data processing and computing infrastructure for spatial applications needs to be established. Over the past decade, grid has become a powerful computing environment for data intensive and computing intensive applications. Integrating grid computing with spatial data processing technology, the authors designed a spatial data processing grid (called SDPG) to address the related problems. Requirements of spatial applications are examined and the architecture of SDPG is described in this paper. Key technologies for implementing SDPG are discussed with emphasis.

  13. Hispanic Heritage Month

    Science.gov (United States)

    York, Sherry

    2004-01-01

    Hispanic heritage month is from September 15 to October 15. One problem that arises when grouping people into categories such as Hispanic or Latino is stereotyping, stereotypes can be promoted or used in this Hispanic month to promote a greater understanding of Latino cultures.

  14. Progress report, 24 months

    DEFF Research Database (Denmark)

    Juhl, Thomas Winther; Nielsen, Jakob Skov

    The work performed during the past 12 months (months 13 – 24) of the project has included the conclusion of Task 1 – Fundamental Studies and Task 2 – Multimirror Cutting Head Design. Work on Task 3 – Compact Cutting Head Design, and Task 4 – Interface Design has been carried out and the tests...... of the multimirror cutting head have been started....

  15. Progress report, 36 months

    DEFF Research Database (Denmark)

    Juhl, Thomas Winther; Nielsen, Jakob Skov

    The work performed during the past 12 months (months 13 – 24) of the project has included the conclusion of Task 1 – Fundamental Studies and Task 2 – Multimirror Cutting Head Design. Work on Task 3 – Compact Cutting Head Design, and Task 4 – Interface Design has been carried out and the tests...... of the multimirror cutting head have been started....

  16. Progress report, 36 months

    DEFF Research Database (Denmark)

    Juhl, Thomas Winther; Nielsen, Jakob Skov

    The work performed during the past 12 months (months 13 – 24) of the project has included the conclusion of Task 1 – Fundamental Studies and Task 2 – Multimirror Cutting Head Design. Work on Task 3 – Compact Cutting Head Design, and Task 4 – Interface Design has been carried out and the tests of ...

  17. Progress report, 24 months

    DEFF Research Database (Denmark)

    Juhl, Thomas Winther; Nielsen, Jakob Skov

    The work performed during the past 12 months (months 13 – 24) of the project has included the conclusion of Task 1 – Fundamental Studies and Task 2 – Multimirror Cutting Head Design. Work on Task 3 – Compact Cutting Head Design, and Task 4 – Interface Design has been carried out and the tests of ...

  18. Mapping of grid faults and grid codes[Wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Iov, F. [Aalborg Univ., Inst. of Energy Technology (Denmark); Hansen, Anca D.; Soerensen, Poul; Cutululis, N.A. [Risoe National Lab. - DTU, Wind Enegy Dept., Roskilde (Denmark)

    2007-06-15

    The objective of this project is to investigate into the consequences of the new grid connection requirements for the fatigue and extreme loads of wind turbines. The goal is also to clarify and define possible new directions in the certification process of power plant wind turbines, namely wind turbines, which participate actively in the stabilisation of power systems. Practical experience shows that there is a need for such investigations. The grid connection requirements for wind turbines have increased significantly during the last 5-10 years. Especially the requirements for wind turbines to stay connected to the grid during and after voltage sags, imply potential challenges in the design of wind turbines. These requirements pose challenges for the design of both the electrical system and the mechanical structure of wind turbines. An overview over the frequency of grid faults and the grid connection requirements in different relevant countries is done in this report. The most relevant study cases for the quantification of the loads' impact on the wind turbines' lifetime are defined. The goal of this report is to present a mapping of different grid fault types and their frequency in different countries. The report provides also a detailed overview of the Low Voltage Ride-Through Capabilities for wind turbines in different relevant countries. The most relevant study cases for the quantification of the loads' impact on the wind turbines' lifetime are defined. (au)

  19. First Experiences with LHC Grid Computing and Distributed Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, Ian

    2010-12-01

    In this presentation the experiences of the LHC experiments using grid computing were presented with a focus on experience with distributed analysis. After many years of development, preparation, exercises, and validation the LHC (Large Hadron Collider) experiments are in operations. The computing infrastructure has been heavily utilized in the first 6 months of data collection. The general experience of exploiting the grid infrastructure for organized processing and preparation is described, as well as the successes employing the infrastructure for distributed analysis. At the end the expected evolution and future plans are outlined.

  20. Accident of Large-scale Wind Turbines Disconnecting from Power Grid and Its Protection

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    There were many accidents of large-scale wind turbines disconnecting from power grid in 2011. As single- phase-to-ground fault cannot be correctly detected, single-phase-to-ground fault evolved to phase-to-phase fault. Phase-to-phase fault was isolated slowly, thus leading to low voltage. And wind turbines without enough low voltage ride-through capacity had to be disconnected from the grid. After some wind turbines being disconnected from the grid, overvoltage caused by reactive power surplus made more wind turbines disconnect from the grid. Based on the accident analysis, this paper presents solutions to above problems, including travelling waves based single-phase-to-ground protection, adaptive low voltage protection, integrated protection and control, and high impedance fault detection. The solutions lay foundations in theory and technology to prevent large-scale wind turbines disconnecting from the operating power grid.

  1. Pub: Grid 2004, 2 signalement

    DEFF Research Database (Denmark)

    2004-01-01

    2. signalement er en af flere manifesteringer omkring det at skabe en tale omkring udfordringer. Pub: Grid 2004 indeholder en række arbejder, der afspejler et fagligt udviklingsarbejde på afdeling 6....

  2. The Cardiovascular Research Grid (CVRG)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The CardioVascular Research Grid (CVRG) project is creating an infrastructure for sharing cardiovascular data and data analysis tools. CVRG tools are developed using...

  3. Wind energy in offshore grids

    DEFF Research Database (Denmark)

    Schröder, Sascha Thorsten

    and investment implications under different regulatory frameworks are a hitherto underrepresented research field. They are addressed by this thesis. Offshore grids between several countries combine the absorption of wind energy with international power trading. However, the inclusion into an offshore grid......This cumulative PhD thesis deals with wind integration in offshore grids from an economic point of view. It is composed of a generic part and eight papers. As the topic has mostly been analysed with a focus on topology and technical issues until now, market-operational questions in offshore grids...... affects the economics of an offshore wind park. It is shown that the spot market income is lower if an offshore wind farm is placed in an interconnector and subject to nodal pricing instead of having a national affiliation. Moreover, congestion in the interconnector can prevent the wind farm from...

  4. Governments plan data grid projects

    CERN Multimedia

    Thibodeau, Patrick

    2007-01-01

    "Some governments and not-for-profit organizations such as hospitals are beginning to look at data grid technology as a means to improve servies, lower operating costs and spur economic development." (1 page)

  5. Formal Aspects of Grid Brokering

    Directory of Open Access Journals (Sweden)

    Attila Kertész

    2009-12-01

    Full Text Available Coordination in distributed environments, like Grids, involves selecting the most appropriate services, resources or compositions to carry out the planned activities. Such functionalities appear at various levels of the infrastructure and in various means forming a blurry domain, where it is hard to see how the participating components are related and what their relevant properties are. In this paper we focus on a subset of these problems: resource brokering in Grid middleware. This paper aims at establishing a semantical model for brokering and related activities by defining brokering agents at three levels of the Grid middleware for resource, host and broker selection. The main contribution of this paper is the definition and decomposition of different brokering components in Grids by providing a formal model using Abstract State Machines.

  6. The smart grid research network

    DEFF Research Database (Denmark)

    Troi, Anders; Jørgensen, Bo Nørregaard; Larsen, Emil Mahler

    2013-01-01

    for Smart Grid research, development and demonstration It is recommended that the electricity sector invite the Ministry to participate in the creation of a road map to ensure that solutions are implemented and coordinated with related policy areas. The sector should also establish a fast-acting working...... Grid Network’s recommendations’, which relate to strengthening and marketing the research infrastructure that will position Denmark as the global hub for Smart Grid development; strengthening basic research into the complex relationships in electric systems with large quantities of independent parties......-recommendation: Universities, along with relevant electric-industry actors, should establish a working group for the completion of a consolidated road map by the end of 2012.” In its work on this report, the Smart Grid Research Network has focused particularly on part-recommendations 26, 27 and 28 in ‘MAIN REPORT – The Smart...

  7. VT US National Grid Index

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) USNGVT is a U.S. National Grid Index (1000m x 1000m) covering Vermont. It is a polygon feature class originally constructed by the Center for...

  8. Cosmological Simulations using Grid Middleware

    CERN Document Server

    Caniou, Y; Depardon, B; Courtois, H; Teyssier, R

    2006-01-01

    One way to access the aggregated power of a collection of heterogeneous machines is to use a grid middleware, such as DIET, GridSolve or NINF. It addresses the problem of monitoring the resources, of handling the submissions of jobs and as an example the inherent transfer of input and output data, in place of the user. In this paper we present how to run cosmological simulations using the RAMSES application along with the DIET middleware. We will describe how to write the corresponding DIET client and server. The remainder of the paper is organized as follows: Section 2 presents the DIET middleware. Section 3 describes the RAMSES cosmological software and simulations, and how to interface it with DIET. We show how to write a client and a server in Section 4. Finally, Section 5 presents the experiments realized on Grid'5000, the French Research Grid, and we conclude in Section 6.

  9. Formal Aspects of Grid Brokering

    CERN Document Server

    Kertész, Attila; 10.4204/EPTCS.14.2

    2009-01-01

    Coordination in distributed environments, like Grids, involves selecting the most appropriate services, resources or compositions to carry out the planned activities. Such functionalities appear at various levels of the infrastructure and in various means forming a blurry domain, where it is hard to see how the participating components are related and what their relevant properties are. In this paper we focus on a subset of these problems: resource brokering in Grid middleware. This paper aims at establishing a semantical model for brokering and related activities by defining brokering agents at three levels of the Grid middleware for resource, host and broker selection. The main contribution of this paper is the definition and decomposition of different brokering components in Grids by providing a formal model using Abstract State Machines.

  10. U.S. Topographic Grid

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — isotop.bin - topographic data for conterminous U.S. projected on an 8 km grid. Projection is Albers, central meridian = 96 degrees West, base latitude = 0 degrees...

  11. Algebraic surface grid generation in three-dimensional space

    Science.gov (United States)

    Warsi, Saif

    1992-01-01

    An interactive program for algebraic generation of structured surface grids in three dimensional space was developed on the IRIS4D series workstations. Interactive tools are available to ease construction of edge curves and surfaces in 3-D space. Addition, removal, or redistribution of points at arbitrary locations on a general 3-D surface or curve is possible. Also, redistribution of surface grid points may be accomplished through use of conventional surface splines or a method called 'surface constrained transfinite interpolation'. This method allows the user to redistribute the grid points on the edges of a surface patch; the effect of the redistribution is then propagated to the remainder of the surface through a transfinite interpolation procedure where the grid points will be constrained to lie on the surface. The program was written to be highly functional and easy to use. A host of utilities are available to ease the grid generation process. Generality of the program allows the creation of single and multizonal surface grids according to the user requirements. The program communicates with the user through popup menus, windows, and the mouse.

  12. Long-range response in ac electricity grids

    Science.gov (United States)

    Jung, Daniel; Kettemann, Stefan

    2016-07-01

    Local changes in the topology of electricity grids can cause overloads far away from the disturbance [D. Witthaut and M. Timme, Eur. Phys. J. B 86, 377 (2013), 10.1140/epjb/e2013-40469-4], making the prediction of the robustness against changes in the topology—for example, caused by power outages or grid extensions—a challenging task. The impact of single-line additions on the long-range response of dc electricity grids has recently been studied [D. Labavić, R. Suciu, H. Meyer-Ortmanns, and S. Kettemann, Eur. Phys. J.: Spec. Top. 223, 2517 (2014), 10.1140/epjst/e2014-02273-0]. By solving the real part of the static ac load flow equations, we conduct a similar investigation for ac grids. In a regular two-dimensional grid graph with cyclic boundary conditions, we find a power law decay for the change of power flow as a function of distance to the disturbance over a wide range of distances. The power exponent increases and saturates for large system sizes. By applying the same analysis to the German transmission grid topology, we show that also in real-world topologies a long-ranged response can be found.

  13. Smart grid applications and developments

    CERN Document Server

    Mah, Daphne; Li, Victor OK; Balme, Richard

    2014-01-01

    Meeting today's energy and climate challenges require not only technological advancement but also a good understanding of stakeholders' perceptions, political sensitivity, well-informed policy analyses and innovative interdisciplinary solutions. This book will fill this gap. This is an interdisciplinary informative book to provide a holistic and integrated understanding of the technology-stakeholder-policy interactions of smart grid technologies. The unique features of the book include the following: (a) interdisciplinary approach - by bringing in the policy dimensions to smart grid technologi

  14. Accurate and Less-Disturbing Active Antiislanding Method Based on PLL for Grid-Connected Converters

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Agelidis, Vassilios G.; Teodorescu, Remus;

    2010-01-01

    An accurate and less-disturbing active antiislanding method suitable for grid-connected converters using phase-locked loop (PLL) based grid synchronization is proposed in this paper. The orthogonal signal generator required by a single-phase PLL is built using a second-order generalized integrator...

  15. Impact of peak electricity demand in distribution grids: a stress test

    NARCIS (Netherlands)

    Hoogsteen, Gerwin; Molderink, Albert; Hurink, Johann L.; Smit, Gerardus Johannes Maria; Schuring, Friso; Kootstra, Ben

    2015-01-01

    The number of (hybrid) electric vehicles is growing, leading to a higher demand for electricity in distribution grids. To investigate the effects of the expected peak demand on distribution grids, a stress test with 15 electric vehicles in a single street is conducted and described in this paper.

  16. GPM, METOP-A, GMI,MHS Level 3 Monthly GPROF Profiling VV03B

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  17. GPM, F17,GMI,SSMI Level 3 Monthly GPROF Profiling VV03B

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  18. GPM, METOP-B, GMI,MHS Level 3 Monthly GPROF Profiling VV03A

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  19. GPM, METOP-A, GMI,MHS Level 3 Monthly GPROF Profiling VV03A

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  20. GPM, TRMM, GMI,TMI Level 3 Monthly GPROF Profiling VV03A

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  1. GPM, NOAA19, GMI,MHS Level 3 Monthly GPROF Profiling VV03B

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  2. GPM, F17,GMI,SSMI Level 3 Monthly GPROF Profiling VV03A

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  3. GPM, F18,GMI,SSMI Level 3 Monthly GPROF Profiling VV03B

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  4. GPM, NOAA19, GMI,MHS Level 3 Monthly GPROF Profiling VV03A

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  5. GPM, TRMM, GMI,TMI Level 3 Monthly GPROF Profiling VV03B

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  6. GPM, F16,GMI,SSMI Level 3 Monthly GPROF Profiling VV03A

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  7. Extended Reconstructed Sea Surface Temperature (ERSST) Monthly Analysis, Version 3b

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Version 3b (v3b) of the Extended Reconstructed Sea Surface Temperature (ERSST) dataset is a monthly SST analysis on a 2-degree global grid based on the International...

  8. GPM, NOAA18, GMI,MHS Level 3 Monthly GPROF Profiling VV03B

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  9. GPM, F18,GMI,SSMI Level 3 Monthly GPROF Profiling VV03A

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  10. GPM, NOAA18, GMI,MHS Level 3 Monthly GPROF Profiling VV03A

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  11. GPM, F16,GMI,SSMI Level 3 Monthly GPROF Profiling VV03B

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  12. GPM, METOP-B, GMI,MHS Level 3 Monthly GPROF Profiling VV03B

    Data.gov (United States)

    National Aeronautics and Space Administration — 3GPROF products provide global gridded monthly/daily precipitation averages from multiple satellites that can be used for climate studies. The 3GPROF products are...

  13. Application of Fractal Grids in Industrial Low-Swirl combustion

    NARCIS (Netherlands)

    Thij, ten G.D.; Verbeek, A.A.; Meer, van der T.H.

    2016-01-01

    Fractal-grid-generated turbulence is a successful technique to significantly increase the reaction rate in the center of a low-swirl flame. Previous results (Verbeek et al. Combust. Flame 162(1), 129–143, 2015) are promising, but the experiments are only performed using natural gas at a single equiv

  14. Review of the correlation developments and a new concept based on mixing mechanism for heat transfer enhancement of spacer grids

    Energy Technology Data Exchange (ETDEWEB)

    Mao, H.; Yang, B.W.; Liu, X. [Xi' an Jiaotong Univ., Shaanxi (China). Science and Technology Center for Advanced Nuclear Fuel Research

    2016-07-15

    Spacer grids could cause heat transfer enhancement both at the spacer grid regions and downstream of the spacer grids as a result of mixing promoted by the spacer grids in the rod bundle. This phenomenon has been demonstrated by many experiments, and several correlations have been developed based on these experimental data. This paper gives a review of the grid-enhanced heat transfer correlation developments in single phase flow. Following the exploration of the correlation development history, a predictive formulation of grid-enhanced heat transfer in single phase flow is established taking into account the effect of both swirl flow and crossflow. With emphasis on modeling of the mixing mechanism associated with the mixing vane grid, the new correlation could better reflect the physical process of the heat transfer augmentation, while a large number of experimental data are needed to determine the coefficients of the new correlation.

  15. On the uncertainties associated with using gridded rainfall data as a proxy for observed

    Science.gov (United States)

    Tozer, C. R.; Kiem, A. S.; Verdon-Kidd, D. C.

    2012-05-01

    Gridded rainfall datasets are used in many hydrological and climatological studies, in Australia and elsewhere, including for hydroclimatic forecasting, climate attribution studies and climate model performance assessments. The attraction of the spatial coverage provided by gridded data is clear, particularly in Australia where the spatial and temporal resolution of the rainfall gauge network is sparse. However, the question that must be asked is whether it is suitable to use gridded data as a proxy for observed point data, given that gridded data is inherently "smoothed" and may not necessarily capture the temporal and spatial variability of Australian rainfall which leads to hydroclimatic extremes (i.e. droughts, floods). This study investigates this question through a statistical analysis of three monthly gridded Australian rainfall datasets - the Bureau of Meteorology (BOM) dataset, the Australian Water Availability Project (AWAP) and the SILO dataset. The results of the monthly, seasonal and annual comparisons show that not only are the three gridded datasets different relative to each other, there are also marked differences between the gridded rainfall data and the rainfall observed at gauges within the corresponding grids - particularly for extremely wet or extremely dry conditions. Also important is that the differences observed appear to be non-systematic. To demonstrate the hydrological implications of using gridded data as a proxy for gauged data, a rainfall-runoff model is applied to one catchment in South Australia initially using gauged data as the source of rainfall input and then gridded rainfall data. The results indicate a markedly different runoff response associated with each of the different sources of rainfall data. It should be noted that this study does not seek to identify which gridded dataset is the "best" for Australia, as each gridded data source has its pros and cons, as does gauged data. Rather, the intention is to quantify

  16. On the uncertainties associated with using gridded rainfall data as a proxy for observed

    Directory of Open Access Journals (Sweden)

    C. R. Tozer

    2012-05-01

    Full Text Available Gridded rainfall datasets are used in many hydrological and climatological studies, in Australia and elsewhere, including for hydroclimatic forecasting, climate attribution studies and climate model performance assessments. The attraction of the spatial coverage provided by gridded data is clear, particularly in Australia where the spatial and temporal resolution of the rainfall gauge network is sparse. However, the question that must be asked is whether it is suitable to use gridded data as a proxy for observed point data, given that gridded data is inherently "smoothed" and may not necessarily capture the temporal and spatial variability of Australian rainfall which leads to hydroclimatic extremes (i.e. droughts, floods. This study investigates this question through a statistical analysis of three monthly gridded Australian rainfall datasets – the Bureau of Meteorology (BOM dataset, the Australian Water Availability Project (AWAP and the SILO dataset. The results of the monthly, seasonal and annual comparisons show that not only are the three gridded datasets different relative to each other, there are also marked differences between the gridded rainfall data and the rainfall observed at gauges within the corresponding grids – particularly for extremely wet or extremely dry conditions. Also important is that the differences observed appear to be non-systematic. To demonstrate the hydrological implications of using gridded data as a proxy for gauged data, a rainfall-runoff model is applied to one catchment in South Australia initially using gauged data as the source of rainfall input and then gridded rainfall data. The results indicate a markedly different runoff response associated with each of the different sources of rainfall data. It should be noted that this study does not seek to identify which gridded dataset is the "best" for Australia, as each gridded data source has its pros and cons, as does gauged data. Rather, the intention is

  17. TARP Monthly Housing Scorecard

    Data.gov (United States)

    Department of the Treasury — Treasury and the U.S. Department of Housing and Urban Development (HUD) jointly produce a Monthly Housing Scorecard on the health of the nation’s housing market. The...

  18. Lightship Monthly Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Daily Weather Observations (Monthly Form 1001) from lightship stations in the United States. Please see the 'Surface Weather Observations (1001)' library for more...

  19. Oceanographic Monthly Summary

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic Monthly Summary contains sea surface temperature (SST) analyses on both regional and ocean basin scales for the Atlantic, Pacific, and Indian Oceans....

  20. Capability of DFIG WTS to ride through recurring asymmetrical grid faults

    DEFF Research Database (Denmark)

    Chen, Wenjie; Blaabjerg, Frede; Chen, Min;

    2014-01-01

    The Wind Turbine Systems (WTS) are required to ride through recurring grid faults in some countries. In this paper, the capability of Doubly Fed Induction Generator (DFIG) WTS to ride through recurring asymmetrical grid faults is evaluated and compared with the ride through capability under single...... asymmetrical grid fault. A mathematical model of the DFIG under recurring asymmetrical grid faults is represented. The analysis are verified by simulations on a 1.5MW DFIG model and by experiments on a reduced-scale DFIG test system....