23 research outputs found

    Avaliação de cultivares de pereira no município de Vacaria na safra 2013-2014.

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    O objetivo deste trabalho foi avaliar a adaptação de cultivares europeias e híbridas de pereira em Vacaria, RS

    Avaliação Agronômica da Ameixeira 'Letícia' em Vacaria, RS.

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    The ESPRI project: astrometric exoplanet search with PRIMA I. Instrument description and performance of first light observations

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    The ESPRI project relies on the astrometric capabilities offered by the PRIMA facility of the Very Large Telescope Interferometer for the discovery and study of planetary systems. Our survey consists of obtaining high-precision astrometry for a large sample of stars over several years and to detect their barycentric motions due to orbiting planets. We present the operation principle, the instrument's implementation, and the results of a first series of test observations. A comprehensive overview of the instrument infrastructure is given and the observation strategy for dual-field relative astrometry is presented. The differential delay lines, a key component of the PRIMA facility which was delivered by the ESPRI consortium, are described and their performance within the facility is discussed. Observations of bright visual binaries are used to test the observation procedures and to establish the instrument's astrometric precision and accuracy. The data reduction strategy for astrometry and the necessary corrections to the raw data are presented. Adaptive optics observations with NACO are used as an independent verification of PRIMA astrometric observations. The PRIMA facility was used to carry out tests of astrometric observations. The astrometric performance in terms of precision is limited by the atmospheric turbulence at a level close to the theoretical expectations and a precision of 30 micro-arcseconds was achieved. In contrast, the astrometric accuracy is insufficient for the goals of the ESPRI project and is currently limited by systematic errors that originate in the part of the interferometer beamtrain which is not monitored by the internal metrology system. Our observations led to the definition of corrective actions required to make the facility ready for carrying out the ESPRI search for extrasolar planets.Comment: 32 pages, 39 figures, Accepted for publication in Astronomy and Astrophysic

    Dispersori di terra per sistemi elettrici di distribuzione. Nuove soluzioni per bonifica e realizzazione

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    Vengono illustrate alcune possibilità offerte dall’utilizzo di elementi infissi a media e grande profondità nella bonifica e realizzazione di impianti di terra per reti gestite con centro stella a terra. Nella prima parte del lavoro viene discussa la possibilità di bonifica di dispersori di impianto con picchetti infissi a grande profondità. Viene quindi descritto nel dettaglio un intervento di bonifica di una Cabina Primaria esistente. Nella seconda parte viene trattato il problema della bonifica dei dispersori di linea confrontando le caratteristiche di dispersori di nuova geometria a quelli tradizionali unificati ENEL. Nella terza parte vengono riportati alcuni dati relativi ad otto interventi di bonifica con la tecnica dei dispersori a grande profondità su altrettante CP dell’ENEL Direzione Distribuzione Trivenet
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