106 research outputs found

    Monitoramento agroambiental do setor sucroenergético: contribuições do sensoriamento remoto orbital para a certificação ambiental do cultivo da cana-de-açúcar.

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    The potential for Brazilian sugarcane ethanol production and exportation is linked, among others, to environmental sustainability and certification. The objective of this work was to present the major activities carried out within the context of the Canasat Project that can contribute to the compliance of some certification guidelines for sustainable sugarcane ethanol production. The microregion of Auriflama in the State of São Paulo, Brazil was selected as study area. Remote sensing images from TM, AWiFS, CCD and HRC sensors were used to: 1) map sugarcane crop for crop year 2009/10; 2) map sugarcane harvest practice (with and without straw burning) during crop year 2009/10; 3) sugarcane cultivation in permanent protected areas (APP) by law; 4) land use and land cover change in remanescents of native vegetation (RVN), and 5) land use and land cover change due to sugarcane expansion. The municipalities of General Salgado, Magda and São João de Iracema presented the largest amount of cultivated sugarcane in the study area. It was also observed that pasture released the largest amount of land (80%) for sugarcane expansion. The municipalities of Guzolândia, Gastão Vidigal, Floreal, Magda and Auriflama presented the highest percentages of sugarcane harvested without the practice of straw burning surpassing the goal established by the Agri-environmental Protocolo for the year of 2009. The municipalities of General Salgado and Auriflama presented the largest amount of cultivated sugarcane in APP with 1.1% and 0.4%, respectively. The municipalities of Nova Castilho and Gastão Vidigal had, respectively, 68.7 ha (8.3%), 16.1 ha (4.5%) of RVN suppressed. The applied method and the integrated analyses allowed to, preliminary, evaluate the adherence of sugarcane producers to a sustainable ethanol production, in the microregion of Auriflama, based on some proposed directives for the certification of ethanol production

    Threshold electronic structure at the oxygen K edge of 3d transition metal oxides: a configuration interaction approach

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    It has been generally accepted that the threshold structure observed in the oxygen K edge X-ray absorption spectrum in 3d transition metal oxides represents the electronic structure of the 3d transition metal. There is, however, no consensus about the correct description. We present an interpretation, which includes both ground state hybridization and electron correlation. It is based on a configuration interaction cluster calculation using a MO6 cluster. The oxygen K edge spectrum is calculated by annihilating a ligand hole in the ground state and is compared to calculations representing inverse photoemission experiments in which a 3d transition metal electron is added. Clear differences are observed related to the amount of ligand hole created in the ground state. Two "rules" connected to this are discussed. Comparison with experimental data of some early transition metal compounds is made and shows that this simple cluster approach explains the experimental features quite well.Comment: 10 pages, submitted to Phys. Rev. B, tried to make a better PS file
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