Green nanocomposites as carriers for slow-release of tebuconazole.

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Avaliação de unidade de apodrecimento de madeiras.

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Utilização de casca de pinhão para fabricação de compósitos.

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Alginate / cellulose beads as supports for slowrelease of nutrient.

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Thermal tools to evaluation of decayed and weathered wood polymer composites prepared by in situ polymerization.

This study aims to apply thermal tools in the evaluation of decayed and weathered wood polymer composites prepared by in situ polymerization of methyl methacrylate (MMA) using glycidyl methacrylate (GMA) and methacrylic acid (MAA) as cross-linkers. The pine wood samples were impregnated in a vacuum/pressure system and polymerized in an oven at 90°C for 10h, using benzoyl peroxide at 1.5 wt% as catalyst. The untreated wood and composites were exposed to in vitro decay tests with Trametes versicolor and Gloeophyllum trabeum fungi, and to artificial weathering. The weight loss after tests was measured, and the characterization was performed by thermogravimetric (TGA) and differential scanning calorimetry (DSC) analysis. The mass loss caused by exposure to fungi was evidently higher in untreated wood in relation to the composites, ~2.5 to 10 times - the composites with GMA and MAA showed the highest resistance to both fungi. The composites without cross-linkers showed the higher mass loss in the artificial weathering tests (>11%), due to the leaching of part of poly(MMA) formed inside wood. By TGA and DSC analysis, we observed shifting in the temperature of thermal events related to polysaccharides and lignin after exposed to decays tests ? more significant changes were for Trametes versicolor tests. The thermograms related to weathered samples showed different results for each composite. The untreated wood and the composite without cross-linker presented loss in lignin, meanwhile the composites with cross-linkers presented degradation in the copolymer formed onto surface of wood. Keywords: TGA, DSC, pinewood, methacrylate, additivesCBRATEC

Thermal analysis of byproducts from fast-pyrolysis of Eucalyptus flour.

Fast pyrolysis is the thermal decomposition of biomass in the absence of oxygen. This study aims to evaluate thermal analysis of byproducts from fast-pyrolysis of Eucalyptus wood fines. The pyrolysis was conducted in a pilot-scale at 500°C and 100 mm H2O. Charcoal from this process showed high ash content (over than 20%) and incomplete carbonization. Aqueous extract and bio-oil showed similar thermal decomposition events. However, mass percentage decomposed at each temperature was different between these samples.Edição dos Anais do 7º Simpósio de Análise Térmica, 2015, Bauru

First passages in bounded domains: When is the mean first passage time meaningful?

We study the first passage statistics to adsorbing boundaries of a Brownian motion in bounded two-dimensional domains of different shapes and configurations of the adsorbing and reflecting boundaries. From extensive numerical analysis we obtain the probability P(\omega) distribution of the random variable \omega=\tau_1/(\tau_1+\tau_2), which is a measure for how similar the first passage times \tau_1 and \tau_2 are of two independent realisations of a Brownian walk starting at the same location. We construct a chart for each domain, determining whether P(\omega) represents a unimodal, bell-shaped form, or a bimodal, M-shaped behaviour. While in the former case the mean first passage time (MFPT) is a valid characteristic of the first passage behaviour, in the latter case it is an insufficient measure for the process. Strikingly we find a distinct turnover between the two modes of P(\omega), characteristic for the domain shape and the respective location of absorbing and reflective boundaries. Our results demonstrate that large fluctuations of the first passage times may occur frequently in two-dimensional domains, rendering quite vague the general use of the MFPT as a robust measure of the actual behaviour even in bounded domains, in which all moments of the first passage distribution exist.Comment: 9 pages, 6 figure

Avaliação de mourões de Corymbia citriodora Hill & Johnson tratados com CCA-C após 6 anos em ensaio de campo de apodrecimento.

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Caracterização dos solos em áreas manejadas com bacurizeiros nativos nas mesorregiões do Nordeste paraense e Marajó.

A distribuição geográfica de bacurizeiros (Platonia insignis Mart.) é controlada por fatores naturais e antrópicos que contribuem para sua ocorrência e concentração de populações manejadas desta espécie, nas mesorregiões do Nordeste Paraense e Marajó. Com base nessa hipótese, este trabalho teve como objetivo a caracterização dos solos de sítios com bacurizeiros manejados nestas duas mesorregiões..