55 research outputs found

    Release properties of UCx_x and molten U targets

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    The release properties of UCx_x and molten U thick targets associated with a Nier- Bernas ion source have been studied. Two experimental methods are used to extract the release time. Results are presented and discussed for Kr, Cd, I and Xe

    A compilation of global bio-optical in situ data for ocean colour satellite applications – version three

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    A global in situ data set for validation of ocean colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI) is presented. This version of the compilation, starting in 1997, now extends to 2021, which is important for the validation of the most recent satellite optical sensors such as Sentinel 3B OLCI and NOAA-20 VIIRS. The data set comprises in situ observations of the following variables: spectral remote-sensing reflectance, concentration of chlorophyll-a, spectral inherent optical properties, spectral diffuse attenuation coefficient, and total suspended matter. Data were obtained from multi-project archives acquired via open internet services or from individual projects acquired directly from data providers. Methodologies were implemented for homogenization, quality control, and merging of all data. Minimal changes were made on the original data, other than conversion to a standard format, elimination of some points, after quality control and averaging of observations that were close in time and space. The result is a merged table available in text format. Overall, the size of the data set grew with 148 432 rows, with each row representing a unique station in space and time (cf. 136 250 rows in previous version; Valente et al., 2019). Observations of remote-sensing reflectance increased to 68 641 (cf. 59 781 in previous version; Valente et al., 2019). There was also a near tenfold increase in chlorophyll data since 2016. Metadata of each in situ measurement (original source, cruise or experiment, principal investigator) are included in the final table. By making the metadata available, provenance is better documented and it is also possible to analyse each set of data separately. The compiled data are available at https://doi.org/10.1594/PANGAEA.941318 (Valente et al., 2022)

    A compilation of global bio-optical in situ data for ocean colour satellite applications – version three

    Get PDF
    A global in situ data set for validation of ocean colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI) is presented. This version of the compilation, starting in 1997, now extends to 2021, which is important for the validation of the most recent satellite optical sensors such as Sentinel 3B OLCI and NOAA-20 VIIRS. The data set comprises in situ observations of the following variables: spectral remote-sensing reflectance, concentration of chlorophyll-a, spectral inherent optical properties, spectral diffuse attenuation coefficient, and total suspended matter. Data were obtained from multi-project archives acquired via open internet services or from individual projects acquired directly from data providers. Methodologies were implemented for homogenization, quality control, and merging of all data. Minimal changes were made on the original data, other than conversion to a standard format, elimination of some points, after quality control and averaging of observations that were close in time and space. The result is a merged table available in text format. Overall, the size of the data set grew with 148 432 rows, with each row representing a unique station in space and time (cf. 136 250 rows in previous version; Valente et al., 2019). Observations of remote-sensing reflectance increased to 68 641 (cf. 59 781 in previous version; Valente et al., 2019). There was also a near tenfold increase in chlorophyll data since 2016. Metadata of each in situ measurement (original source, cruise or experiment, principal investigator) are included in the final table. By making the metadata available, provenance is better documented and it is also possible to analyse each set of data separately. The compiled data are available at https://doi.org/10.1594/PANGAEA.941318 (Valente et al., 2022)

    Superconducting electric machines in watercraft

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    Superconductors, especially high temperature superconductors (HTS) are used in electric machines. Superconducting generators and motors have smaller mass and overall dimensions in comparison to conventional machines. Because of these specific quality that solutions are interested for ship propulsion applications. Current density in HTS superconducting winding may be two orders of magnitude higher than in copper windings, which allows to reach two times higher magnetic field density in the gap of synchronous machine, even without iron in the rotor and slots in the stator of the motor. Such design of synchronous machine can substantially reduce the distortion of current and voltage waveforms, as well as the acoustic effects. The construction without iron in rotor and higher magnetic induction makes the superconducting machine, with cooling system, several times lighter than conventional ones. The electric machines could be used in ships and airplanes where smaller dimensions and weight of propulsion equipment results in growth of ship displacement and cargo space. In ship propulsion supplied by generator with frequency converter, high speed generators e.g. 16 000 rpm (800 Hz) and low speed motors e.g. 230 rpm (115 Hz) are preferred for big weight decreasing. Paper presents basic knowledge about superconductors, the construction principles of electric superconducting devices and the examples of generators and motors with HTS winding. The parameters of these superconductor generators and motors were described too
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