385 resultados para Propagação assexuada


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Pós-graduação em Engenharia Mecânica - FEIS

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

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Pós-graduação em Engenharia Mecânica - FEG

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For engineering projects that require high reliability levels, is often not enough know only physical and chemical material properties. It’s necessary understand the failure mode of these materials in operation to ensure security level in the project and establish more stringent criteria in the analysis of structural integrity. Due to this need, aircraft industry has been using aluminum alloys in their designs and projects. “Currently more than 70% of aircraft structures are built of high strength aluminum alloys among which stand out 7075-T6 and 2024-T3 alloys, which are considered basics for being used in the new alloys development.” (PASTOUKHOV & VOORWALD, 1995). Some years ago ALCOA develops Al 2524 alloy that has emerged as refinement of Al 2024 (Al, Cu. Mg) alloy, with purpose of improve fracture toughness and fatigue resistance on structural components. The present research addresses testing of fatigue crack propagation under variable amplitude loading for Al 2024 alloy, observing the interaction effects from application of overhead blocks and plastic zone at the crack tip and makes an analysis of fracture surface images

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In this work a study of an API 5L X70 steel, which is used in the manufacture of oil and gas pipelines, has been made. This class of steel show high strength and ductility values, and has been increasingly studied due the growing demand of oil and natural gas, which in consequence, increases the needing of new pipelines to transport them. The material studied has been directly taken from a tube provided by TenarisConfab, and a special attention has been given to the fatigue crack growth rate study, which proved that a crack will grow at different rates according to the tube position where it is growing

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Pós-graduação em Engenharia Mecânica - FEG

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Pós-graduação em Agronomia (Horticultura) - FCA

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The physic nut can be propagated asexually or sexually. Using cuttings have been earlier yield and more fidelity characteristics of the parent plant. However, there is less initial vegetative growth. The seeds from the plants have increased genetic variability, are more vigorous and begin production later. To get quality changes, the substrate is an important factor. With that the objective was to taste pre-germinated treatments and different substrate on seeds emergence and quality physic nut seedlings. The experimental design was completely randomized, in factorial scheme 6 x 3 (pre-germinated treatments x substrate), 18 treatments and 4 repetition, 8 seeds to each repetition. It was evaluated six pre-germination treatments: T1: witness (without treatments); T2: water immersion for 12 hours; T3: water immersion for 24 hours; T4: mechanical scarification; T5: mechanical scarification + water immersion for 12 hours; T6: mechanical scarification + water immersion for 24 hours, using as substrate: commercial, expanded vermiculite and sand washed. The mechanical scarification was realized opposite the micropyle using sandpaper n. 60. After the pre-germination treatments, the seeds were emergence in plastic cups (200mL) with substrates. We evaluated the characteristics: percentage, beginning and emergence speed index, mean length of plant, diameter of plant stem, SPAD index, fresh and dry shoot and root. The results showed that in seeds of Jatropha do not need pre-germinative treatments; and the use of commercial substrate showed seedling development.

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There is great genetic diversity of rambutan plants, thus, to establish commercial orchards culture, it is recommended the use of plants vegetatively propagated. Therefore, this research aimed to determine the best method of grafting, graft protection and type of rootstock for its propagation. The experiment was repeated in two seasons (autumn/winter and spring/summer). The experimental design was completely randomized in both experiments, with four replicates, each experimental unit consisted of 10 plants analyzed in a 4x2x2 factorial with four types of grafting (whip graft-WG; cleft graft -CG; wedge graft-WG; and inverted wedge graft-IWG;), 2 types of graft protection (Biodegradable and plastic) and 2 types of rootstock (without or with leaves). The variables analyzed in this study were: percentage of grafting success, number and length of buds (cm). For grafting performed in autumn /winter, both by cleft grafting as whip graft with biodegradable strip and rootstock leafless provided the best results in propagation of rambutan tree. The best results were observed during the autumn / winter.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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In this paper it was evaluated the influence of the relative position of logs on the trees, the type of wood (juvenile and mature wood and pith) and the dimension of sawed wood elements on the velocity of propagation of stress waves into the material on condition. P. taeda L wood (43 years old trees) from Horto Florestal of Manduri (latitude 230 00’ south, longitude 400 19’ west and altitude de 700 m) São Paulo State, Brazil were used, considering its easy growth rings visualization and the better ju regions definition. Six trees were randomly chosen in the plantation. Trees were sawed into 4 logs (2,5 m long each. In each log it was delimited the central board (80mm tick) region and the lateral boards (25mm tick) regions, cons right hand. It were evaluated relation between velocity of stress waves on logs and the correspondent lumber (central and lateral boards), on green condition, on the three main region of the elements (mature wood results obtained revealed the concordance between velocities of stress waves in the material before and after the its mechanical processing. It was also revealed statistical differences between the velocity of stress waves at juvenile wood, mature wood and pith regions. Keywords: stress wave method, velocity 17 destrutivos de propagação da propagação de ondas de tensão em toras e madeira serrada de taeda L. Hernando Alfonso Lara Palma - Universidade Estadual Paulista Faculdade de Ciências Agronômicas – FCA/UNESP – Botucatu - SP, e-mail: awballarin@fca.unesp.br Luiz Antonio Vasques Hellmeister - Universidade Estadual Paulista - Faculdade de Arquitetura, FAAC/UNESP – Bauru - SP, e-mail: hellmeister@faac.unesp.br Este trabalho teve como objetivo analisar a influência do tipo de lenho, da posição da tora ao longo do fuste e das dimensões das peças desdobradas, na velocidade de as de tensão (Stress wave method), na condição de madeira verde. P. taeda L., originária de árvores de plantio do Horto Florestal de SP., com idade aproximada de 43 anos, pela facilidade de identificação dos anéis imento e demarcação das regiões de madeira adulta e madeira juvenil. Foram amostradas 6 árvores distintas, escolhidas ao acaso do talhão selecionado. De cada árvore foram retiradas 4 toras com comprimento de 2,5 m cada. Foram demarcadas nas toras a ha central (8 cm de espessura) e 4 tábuas laterais (espessura comercial de 2,5 cm), sendo duas à esquerda e duas à direita da prancha central. Foram avaliadas as relações existentes entre as velocidades de propagação das ondas de tensão na madeira íntegra (toras) e desdobrada (pranchas e tábuas), na condição de madeira verde, nas três regiões distintas do lenho: medula, madeira adulta e madeira juvenil. A análise comparativa dos resultados revelou a concordância entre as velocidades antes e após o desdobr madeira. Houve diferenciação estatisticamente significativa entre as velocidades de propagação das ondas de tensão nos lenhos adulto, juvenil e na medula. -destrutivos, método das ondas de tensão, Pinus taeda stress wave tests on green logs and lumber of Pinus taeda In this paper it was evaluated the influence of the relative position of logs on the trees, the type of wood (juvenile and mature wood and pith) and the dimension of sawed wood elements on the velocity of propagation of stress waves into the material on L wood (43 years old trees) from Horto Florestal of Manduri (latitude 19’ west and altitude de 700 m) São Paulo State, Brazil were used, considering its easy growth rings visualization and the better juvenile and mature wood regions definition. Six trees were randomly chosen in the plantation. Trees were sawed into 4 logs (2,5 m long each. In each log it was delimited the central board (80mm tick) region and the lateral boards (25mm tick) regions, considering 2 boards on the left and 2 at the right hand. It were evaluated relation between velocity of stress waves on logs and the correspondent lumber (central and lateral boards), on green condition, on the three main region of the elements (mature wood, juvenile wood and pith). Comparative analyses of results obtained revealed the concordance between velocities of stress waves in the material before and after the its mechanical processing. It was also revealed statistical differences ty of stress waves at juvenile wood, mature wood and pith regions

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