199,506 research outputs found

    Payloads development for European land mobile satellites: A technical and economical assessment

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    The European Space Agency (ESA) has defined two payloads for Mobile Communication; one payload is for pre-operational use, the European Land Mobile System (EMS), and one payload is for promoting the development of technologies for future mobile communication systems, the L-band Land Mobile Payload (LLM). A summary of the two payloads and a description of their capabilities is provided. Additionally, an economic assessment of the potential mobile communication market in Europe is provided

    Birational geometry of defective varieties

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    Here we investigate the birational geometry of projective varieties of arbitrary dimension having defective higher secant varieties. We apply the classical tool of tangential projections and we determine natural conditions for uniruledness, rational connectivity, and rationality

    System test approach for the SAX satellite

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    SAX satellite verification is based on a protoflight approach, in which only one system model is realized at flight standard level, taking into account the utilization of hardware already qualified for other space programs and the necessity to respect the schedule constraints for a scientific objective. In any case, this approach was tailored with some deviations in order to reduce risks inherent in such a choice. The protoflight approach was also pursued at subsystem/unit level in particular for those subsystems and units considered critical from the schedule point of view. Payload Instruments followed the same approach but complete spare units were developed to reduce the risks associated with such an approach. A description of the model philosophy is provided and then, at satellite level, the testing approach and rationale for each model is presented. Finally, a brief description of each test will be given, highlighting objectives, methodologies, and test configurations. Moreover, for the major tests, problems encountered and solutions applied in establishing a correct approach are described

    NaturWall©: facciate in legno multifunzionali per la riqualificazione del patrimonio edilizio / NaturWall©:multifunctional wood façade in existent building refurbishment

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    Naturwall© is a research conducted by Politecnico of Turin (DAD) (under supervision of Prof.G.Callegari) and a local PMI support (Natural House, Castellamonte), promoted by Giovanni Goria Foundation "Master dei Talenti" programme. It consists in an innovative energy saving system by using wood multifunctional components for existent buildings . The goal of the project is the refurbishment of the existing building stock which were built from 1950's to 1980's. This stock is not equipped with recent energy requirements. The project aims to create a representative model of solution that will be promoted in Italy. In the field of renovation and refurbishment high energy results and greenhouse gases reduction could be achieved by using multifunctional facade system
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