605 resultados para eucalipto


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV

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Pós-graduação em Microbiologia Agropecuária - FCAV

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The connections in the wood structures are the places with high concentrations of stresses and therefore are more fragile than the rest of the structure. The connections between pieces of wood can be made by metal pins (nails or screws). The compression and embedment strength has significant influence on the calculation of the connections. The main aim of this work was to evaluate the compression and embedment strength in the directions parallel, inclined at 45° and normal to the grain, using standard specimens according to ABNT NBR 7190/1997 standard. The compression and embedment strength were initially evaluated according to ABNT NBR 7190/1997, which admits the deformation of 2‰ as limit of embedment and the ratio between the ultimate strength and the area of application of load in the specimen for the compressive strength. Afterward, the embedment strength was evaluated by the EUROCEDE 5 /1995 European standard, which use the limit of 5 mm of the displacement for the embedment. Specimens of Pinus oocarpa, Cumaru and Pinus taeda were used in tests to calibration of equipment and specimens of Pinus taeda and Eucalipto citriodora were used to compare the results of strength. The results of strength were evaluated based on statistical analysis. The results of compressive strength for the Pinus taeda showed no significant differences in embedment strength in the directions parallel and normal to the grain. For the Eucalipto citriodora only in the direction parallel to grain the compression strength was not significant compared with the embedment strength. For both species, only the parallel compression strength and inclined at 45o to the grain, which were to the grain, which were admitted the strain of 2‰ were not significantly different compared with the compression strength determined according to ABNT NBR 7190/1997. The normal compression strength obtained according to ABNT NBR 7190/1997 and ultimate compression strength not ...

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This work was developed to evalute the physical and mechanical properties of a panel of three particle layers from the test specification of NBR 14810-3 (2006), using wood of Eucalyptus sp. and Eucalyptus saligna and Eucalyptus urograndis bark. The mechanical properties were evaluated to obtain the bending modulus of rupture (MOR) and modulus of elasticity (MOE) and Internal bond. The physical properties were obtained thickness sweeling, water absorption, moisture content and board density. Were evaluated four different compositions of panels containing 5, 10, 15 and 20% in the inner layer of bark. The results were compared with the Brazilian standard NBR 14810-2 (2006) and also with studies in the literature. The panels produced were adequate to all the optimal values suggested by the standard only in the composition with 5% skin in the inner layer. The other treatments showed satisfactory results in all tests except for moisture content

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In contrast to what happened in the past where it was possible to select which species had a lower degree of variation, it is now necessary to use fast-growing species with efficient processing. For that we use the wood of Eucalyptus sp and studies related to the machining processes and their parameters such as wear of cutting tools and roughness. The present work aims to analyze the influence of geometry of cutting tools of high speed steel and the influence of the diameter of the final pieces in the process of turning wood of Eucalyptus sp in relation to power consumption, roughness, temperature machining, chip formed and wear of cutting tools. It was observed that the smaller the diameter of the end parts and greater wear of the tools, the worse quality of the machined surfaces and the greater the power consumed in the process of machining

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This work is the production of particleboard of particles reconstituted from MDP (Medium Density Particleboard) adding particles in the inner layer of Mimosa Scarelli, popularly known as bracatinga, the ratios of 0%, 25%, 50%, 75% and 100%. The panel produced is composed of three layers, two external particles with smaller particle size and an inner layer composed of particles of larger particle sizes. Assays were performed based on physical and mechanical NBR 14.810/2006 for the determination of the board density, thickness swelling, water absorption, moisture content, bending strength, shear strength and residual moisture, and testing of particle size not existing in the standard cited. The results were analyzed and compared the results of the commercial boards made from 100% eucalyptus, based on the limits specified by the ABNT NBR 14.810/2006. The values of the tests were close to the normative specifications indicating positively the production of MDP with wood decay.

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A formação de mosaicos de habitats em regiões de reflorestamento e outras atividades antrópicas acabam influenciando na comunidade de mamíferos silvestres, de diferentes formas. Os mamíferos de médio e grande porte têm importantes funções como dispersores de sementes, polinizadores e predadores. Concomitantemente, este grupo de animais vem se tornando cada vez mais ameaçado na Mata Atlântica, especialmente no estado de São Paulo. O presente estudo realizou a caracterização da comunidade de mamíferos silvestres de médio e grande porte, presente em dois ambientes: fragmentos de vegetação natural e talhões de eucalipto. Para tanto, foram utilizados métodos indiretos de registro: observação de pegadas em transectos lineares e em armadilhas de areia. De acordo com a curva acumulativa de espécies, o esforço amostral se mostrou suficiente para registrar as espécies que vivem no ambiente de mata e eucalipto. A riqueza de espécies na mata foi maior que a riqueza nos eucaliptos, sendo este último, um ambiente preferencialmente de passagem, enquanto a mata é um habitat natural para os mamíferos. Entretanto, o ambiente de eucalipto se mostra importante para diversas espécies de mamíferos, que utilizam este ambiente como abrigo e para busca de recursos

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The research aimed to produce sheets of particles with waste processing of Eucalyptus sp bonded with urea-formaldehyde and evaluate the effect of pressure variation in the quality of the boards produced. To do so, the Boards made were divided into two treatments depending on the pressing pressure of 30 to 40 kgf / cm². Once pressings, climatized, the particleboards have been sectioned in test samples, and underwent physical-mechanical tests for determining density, swelling and water absorption, modulus of rupture and elasticity in static bending and internal linking. The particleboards pressed at 40 kgf / cm ² showed the best results

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Due to the rapid development of some species such as pine and eucalyptus and a growing demand for raw materials, timber, there was a need for detailed studies to better use and higher quality in products derived from wood. In order to contribute to to better utilization of wood ,this study aims to analyze the quality of the wood surface after machining Corymbia citrodora around, with varying feed rates (40, 70, 100 mm/mim), shear rate (1.88, 2.19, 2.51 m/s) and with the use of inserts for turning new and used (cemented carbide). 18 were used bodies and each body was made three different assays for each test were a total of 54 tests three replicates. This study will also addres the analysis of power consumption for each of the tests. With the results obtained through experiments, including the surface roughness of parts and power consumption for each test, we try to evaluate the power consumption in machining with the variations in cutting speed and feed, with two tools carbide

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A produção de eucalipto no Brasil, impulsionada pelo avanço na tecnologia florestal, tem alcançado índices satisfatórios a nível mundial nos últimos anos. No entanto, apesar de todo o desenvolvimento já obtido, a realização de novas pesquisas que tenham como objetivo aumentar a produtividade do eucalipto com áreas cultivadas reduzidas é muito relevante. A associação do melhoramento genético convencional com técnicas modernas de cunho biotecnológico é imprescindível para que tal benefício seja alcançado. Dentre as ferramentas moleculares necessárias para que tais objetivos sejam atingidos, a identificação e caracterização de promotores órgão-específico representa uma prioridade. Nesse contexto, um EST de eucalipto com expressão específica em raiz foi identificado pelo nosso grupo junto ao banco de dados do projeto FORESTs. A região promotora correspondente foi então amplificada usando a técnica de genome walking. A fim de dar continuidade ao processo de caracterização funcional deste promotor, no presente estudo o fragmento amplificado foi sequenciado, um cassete de expressão contendo o referido promotor foi construído, e plantas transgênicas de tabaco contendo tal cassete foram obtidas visando futuras análises funcionais

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A biotecnologia define-se pelo uso de conhecimentos sobre os processos biológicos e sobre as propriedades dos seres vivos, com o fim de resolver problemas e criar produtos de utilidade. É importante frisar que uma das principais vantagens da biotecnologia moderna voltada para a área vegetal é a de poder gerar estratégias de melhoramento aplicáveis a diferentes culturas. Uma das principais estratégias de ação nessa área trata da produção de plantas geneticamente modificadas com transgenes de interesse. Nesse contexto, a identificação e caracterização de promotores com padrão de expressão tecido-específico é essencial para que a expressão de tais transgenes em plantas de interesse agronômico e florestal, como em eucalipto, fique limitada a determinados órgãos/tecidos. Assim, o presente trabalho teve por objetivo clonar e sequenciar a região promotora de um gene com expressão específica em raiz de eucalipto cujo produto gênico tem similaridade a uma aquaporina. Uma vez clonado, o promotor foi introduzido em vetor binário e inserido em plantas de tabaco visando a sua caracterização funcional. Além disso, a expressão do gene em estudo foi investigada em eucalipto, e uma analise filogenética comparativa com outras angiospermas foi empreendida

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Environrnental issues are in focus lately, mainly due to climate change that have been registered in recent decades. Some of these changes are attributed to the increased atmospheric concentration of greenhouse gases induce, main1y due to anthropogenic emissions. These gases act by absorbing heat in the form of electromagnetic radiation emitted by the planet, and after a time interval, reissuing such radiation in various directions, including back to the surface, causing overheating of the same. Projections indicate that climate change wiIl tend to increase even more. Because of this, in recent years a number of studies are being conducted on the dynamics of inducers of greenhouse gases, especially C02, because that is primarily responsible for the development of that phenomenon. To better understand the flow of C02 are studied specific areas, as regions bordering the forests, soils that are under preparation for agriculture, urban areas, among others. Forests are an important sink for C02, because during the process of photosynthesis, this molecule is captured and used to obtain glucose. Thus, studies of the regions bordering the forests contribute enough to the understanding of the dynamics of C02. Because it requires a large amount of factors, the concentration of CO2 in a given location is very variable and this makes it much more difficult to understand their dynamics and, consequently, the action of the enhanced greenhouse effect. Being a relatively new area of study, there are many controversies about the consequences of the greenhouse effect, so that the community does not believe that climate change resulting from human action. According to them, such changes are merely natural phenomena and periodicals