564 resultados para recarga subterrânea
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Historicamente a convivência entre a mineração e a população sempre foi problemática, com prejuízos enormes para esta última, que, por problemas da falta de moradia, tem de conviver com a degradação do meio ambiente ao seu redor, como a poluição através da poeira, ruído e vibração. Esse trabalho, com dados coletados na mina subterrânea de carvão Trevo, na região carbonífera de Santa Catarina, coloca em evidência a necessidade da integração Empresa x Comunidade, no sentido da melhoria das técnicas de mineração e do meio ambiente, visando a uma convivência pacífica e tendo como um dos seus principais resultados alertar e despertar a consciência da Empresa ante aos reclamos da comunidade, demonstrando-se com dados, o perigo decorrente do planejamento de uma lavra sem levar em conta as habitações em superfície.
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The cultivation of sugarcane demands the use of herbicides such as Diuron and Hexazinone. Some supply wells from Ribeirão Preto, SP, Brazil, built in the Guarani Aquifer are located in recharge points, and the presence of sandy Quartzarenic Neosol in these areas increases the vulnerability of the groundwater to contamination from herbicides This paper reports the water quality monitored in some wells located in the recharge area and the removal of Diuron and Hexazinone by means of adsorption in granular activated carbon (GAC), preceded or not by preoxidation with chlorine and chlorine dioxide in a pilot plant. The results indicated that Diuron was more strongly adsorbed than Hexazinone and that the saturation time of the GAC in the test with preoxidation was shorter than in the test without preoxidation, which may have occurred mainly due to the formation of by-products that competed with the adsorption of the herbicides.
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By remote sensing, geodatabase digital processing, information and expeditions to Capivara's sub-basin, was possible to identify the changes in the landscape mainly the expansion of eucalyptus, sugar-cane, and orange trees, being the last two, mainly on the Periferic Depression of Basaltic Cuesta. A significant portion of the soil on this geological area is formed from sandstones, providing high permeability to them, making them important places to groundwater recharge areas as sensible to contamination by pesticides. Throughout last decade was observed that the native vegetation fragments stabilization, keeping a reason of 26.5% on the land used between 2000 and 2010. The pasture decrease being substituted by eucalyptus, sugar-cane and orange trees call attention for the changes in the agribusiness model demanded by the current economic and social necessity. Pasture decrease followed by erosions decrease on sub-basin is evidence that these two aspects are strongly related.
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Objective: To evaluate fluoride ion release from two anhydrous glass ionomer cements (GICs) and two resin-modified GICs (RMGICs) before and after recharge with 2% neutral sodium fluoride for 4 min and after surface protection of the Maxxion R GIC with an adhesive system, a cavity varnish and a colorless nail polish. Method: A stainless steel 2x6 mm matrix was used for fabricating 5 specimens of each material, which were immersed in 5 mL of deionized water, renewed every 24 h. Measurements with a potentiometer were performed on days 1, 2, 9 and 17, in the 1st and 2nd phases, and the specimens were buffered with a TISAB III solution. In the 2nd phase, the specimens were subjected to recharge and immersed again in 5 mL of deionized water. In the 3rd phase, the GIC surfaces were protected and readings were made at 5 min, 24 h, 48 h and 72 h. Tukey's post-hoc and Student's t tests were used for statistical analyses (p<0.05). Results: There was statistically significant difference in the comparison between the 1st and 2nd phases for all materials, except at day 2 for Vidrion R and VitroFil LC. In the 3rd phase, it was observed that for all materials, comparison of the first 5 min with the other times revealed statistically significant differences among the means of fluoride ion release. In the comparison with the other times, both the varnish and the colorless nail polish presented statistically significant difference between 24 and 48 h as well as between 24 and 72 h. Conclusion: The anhydrous GICs were more effective in fluoride ion release and recharge compared with the RMGICs. Maxxion R presented a homogeneous and statistically significant behavior in both phases. All materials for surface protection were efficient and the colorless nail polish had the best behavior.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Geociências e Meio Ambiente - IGCE
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Pós-graduação em Geociências e Meio Ambiente - IGCE
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)