284 research outputs found

    Slenderness (H/D-ratio) of umbrella trees

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    GRAIL – Grid Access and Instrumentation Tool

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    Since the release of Globus Toolkit 4 Web services enrich the world of Grid Computing. They provide methods to develop modular Grid applications which can be parallelized easily. The access to Web services is mostly solved by complex command line tools which need a good deal of knowledge of the underlaying Grid technologies. GRAIL is intended to fill the gap between existing Grid access methods and both the developer who wants to utilize the Grid for own developments and the user who wants to access the Grid without much additional knowledge. It simplifies the access and the testing of Web services for the Globus Grid middleware. GRAIL provides an easy to use graphical user interface for executing Web services and enables the user to construct complex relationships between services to realize parallel execution. The underlying framework allows an easy integration of any Web service or other arbitrary task without much additional effort for the developer. Existing technologies, shipped with the Globus Toolkit, are seamlessly integrated into GRAIL

    Influence of ESP collector configuration on reduction of particulate emissions from biomass combustion facility

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    Development of compact electrostatic precipitators (ESPs) for reduction of particulate emissions from small scale biomass combustion is an actual task. Particle mass collection efficiency of an ESP depends from combustion conditions, geometry of precipitator ionizer, collector stage configuration and ESP operation parameters. The investigation of the influence of collector stage configuration on particle mass collection efficiency of a pilot space charge ESP was in the focus of the study. It was shown that the use of tube collector with integrated grounded plates enhanced particle mass collection efficiency. The loading of plates with aerosol provoked particle re-entrainment and decreased long-term ESP mass collection efficiency. The use of grounded brush electrodes ensured effective reduction of particle emissions but resulted in increase of pressure drop in the precipitator. The optimization of cleaning intervals of the ionizer and collector stages increased particle mass collection efficiency. It was shown, that the integration of automatic systems for ionizer and collector cleaning into the space charge ESP enhanced precipitator long-term operation stability and ensured effective reduction of particulate emissions form small scale biomass combustion

    Global CO_2 fluxes inferred from surface air-sample measurements and from TCCON retrievals of the CO_2 total column

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    We present the first estimate of the global distribution of CO_2 surface fluxes from 14 stations of the Total Carbon Column Observing Network (TCCON). The evaluation of this inversion is based on 1) comparison with the fluxes from a classical inversion of surface air-sample-measurements, and 2) comparison of CO_2 mixing ratios calculated from the inverted fluxes with independent aircraft measurements made during the two years analyzed here, 2009 and 2010. The former test shows similar seasonal cycles in the northern hemisphere and consistent regional carbon budgets between inversions from the two datasets, even though the TCCON inversion appears to be less precise than the classical inversion. The latter test confirms that the TCCON inversion has improved the quality (i.e., reduced the uncertainty) of the surface fluxes compared to the assumed or prior fluxes. The consistency between the surface-air-sample-based and the TCCON-based inversions despite remaining flaws in transport models opens the possibility of increased accuracy and robustness of flux inversions based on the combination of both data sources and confirms the usefulness of space-borne monitoring of the CO_2 column
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