991 resultados para Pellets de madeira


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Ciência Florestal - FCA

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In Brazil, the exploration and use of the Hevea brasiliensis Mull Arg. wood at the end of the latex production cycle from 30 to 35 years, is practically unknown. However, one of the most significant problems with its use relates to the high susceptibility of this species wood to the fungus Botryodiplodia theobromae attack, especially during the primary wood processing phase. The present study evaluated the efficacy of four chemicals to control juvenile and adult Hevea brasiliensis wood from the attack of the fungus stainer Botryodiplodia theobromae following the ASTM 4445 (2003) standard. The results showed that the active ingredients separately tested and evaluated in the laboratory; (Quinolinolato Copper - 8 and Carbendazim (T1); Tribromofenol 2-4-6 (T2); Extract-Based Vegetable Tannin (T3); Carbendazim and Prochloraz (T4)) do not totally prevent the contamination of Botryodiplodia theobromae in 5% level of significance

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This study aimed to technically and economically evaluate the Forwarder performance in the first cutting wood extraction from a Eucalyptus grandis plantation. Technical analysis included a movement and timing study by continuous method, and the productivity was determined using the extracted wood volume in cubic meters. Economical analysis included operational costs parameters and wood extraction cost. Results referred to the effective operational performance. Loading and unloading activities responded for more than ¾ of the total time of effective Forwarder operational cycle. Operational costs were influenced by maintenance and repair costs. The estimated cost of extraction was US$ 0.97 per cubic meter.

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The aim of this paper was to perform an energy assessment of firewood and woodshaving use for energy generation in sericulture agroindustry boilers. In this research, we used a boiler from a silk spinning factory located in the city of Duartina, São Paulo, Brazil, that currently uses eucalyptus firewood as fuel to generate water vapour used in silk fiber production. In the studied fuels utilization system energy consumption structure development, we considered energy input in Megajoule (MJ) by type, source and form involved in several firewood use technical itinerary operations, as well as in woodshaving use technical itinerary operations. From these fuels utilization built structure, we performed a firewood- and woodshaving-generated energy input comparative analysis, in Megajoule/hour (MJ.h-1), to produce 2.968,80 kg.h-1 of vapour, which is the boiler average production, during the following years: 2004, 2005, and 2006. The energy analysis results revealed that to replace eucalyptus firewood with woodshaving is something possible in the boiler, reducing total energy consumption approximately by 21%.

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This paper had the objective of determining the transition regions between the juvenile and mature wood of Corymbia citriodora (Eucalyptus citriodora) of 29 years of age from the Experimental Station of Forest Science (EECFA-LCF/ESALQ-USP), located in Anhembi, in the State of São Paulo. The regions of juvenile and mature wood were characterized through anatomical studies - axial fiber length - following the recommendations of the International Association of Wood Anatomists (1989) using disks at the DBH of the trees. The measurements of fiber length were made in equipment for acquisition, diagnosis and image analysis. Five slices were made for every centimeter, in the radial direction and six fiber lengths per slice were measured, producing 30 measurements per sample region. In the total, 1740 lengths of fiber were measured in three disks that were studied. Results indicate a trend of accentuated and linear increase for the length of fibers, from the pith to 11 cm of radial of about 79%. Between 12 cm and 19 cm of the radius, fibers length remained almost constant, and from that point on, the fiber length tended to slightly increase to the bark. It can be concluded that for these trees, at this height of sampling, when the tree has 29 years of age, the extension of the juvenile wood goes up to 52% of its radius.

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A espécie amazônica Paricá (Schizolobium amazonicum Herb) apresenta rápidos incrementos em altura e diâmetro em poucos anos de cultivo e desenvolve uma madeira com pequena quantidade de nós e defeitos, característica fundamental na sua utilização para fins estruturais. O objetivo deste trabalho foi determinar as propriedades de resistência e rigidez de peças da madeira Paricá em dimensões estruturais, de acordo com a norma ABNT NBR 7190: 2011, bem como realizar a classificação visual das peças para determinação de defeitos como: nós, inclinação de fibras, empenamentos, rachas e fendas. Conclui-se que a madeira de Paricá é classificada como classe C 20 das dicotiledôneas e possui baixa densidade, boa resistência à compressão paralela, grande potencial de utilização na construção civil quando comparada com outras espécies e, em relação à classificação visual, poucos nós, grã direita e poucos empenamentos e distorções.

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O objetivo deste trabalho foi estimar o valor econômico e a margem de comercialização da madeira em tora oriunda de áreas manejadas. Essa cadeia, além de produzir margem positiva, os valores são relativamente superiores aos gerados nas atividades que concorrem para o desmatamento na Amazônia para se estabelecerem. Adicionalmente, determinou-se o coeficiente médio de desdobramento de 37,3% (2,68 m3 de madeira em tora para cada 1,0 m3 de madeira serrada), o qual revelou baixo grau tecnológico das empresas. O valor econômico médio da extração e comercialização da madeira em pé no mercado local foi de R$ 23,48/m3, tendo um valor mínimo de R$ 9,06/m3 para as espécies da categoria C4 (madeira branca) e um máximo de R$ 55,63/m3 para as espécies da categoria C1 (madeira especial). Assim, para um fluxo de 30 anos e extração de 25 m3/ha nos planos de manejo das áreas de concessão florestal do Estado do Pará, gera-se um valor médio de R$ 587,00/ha, ou R$ 19,56/ha/ano. No fluxo de 30 anos, esse resultado é relativamente superior ao gerado pelas atividades de pecuária extensiva (em torno de R$ 180,00/ha) e das lavouras de grãos (em torno dos R$ 420,00/ha), principais responsáveis pelo desmatamento da Amazônia. Também, apresenta maior rentabilidade do que o reflorestamento com paricá, que gera R$ 192,26/ha. A margem de comercialização indicou que a sociedade tende a se apropriar de 14,3% do valor econômico gerado na cadeia da madeira oriunda dos contratos de concessão florestal.

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Two new species of Jupiaba Zanata are described from Brazil. Jupiaba iasy, new species, is described from rio Teles Pires and rio Jamanxim, tributaries of rio Tapajos, and from rio Aripuana, in the rio Madeira drainage. It is distinguished from its congeners by its color pattern consisting of a single posteriorly displaced dark crescent-shaped humeral blotch, situated over the first 5 to 7 lateral line scales, and an inconspicuous dark spot at the end of caudal peduncle. It also differs from all remaining Jupiaba for the following combination of characters: 34-36 lateral line scales, 19-21 branched anal-fin rays, 8-10 predorsal scales arranged in a regular row, 6 horizontal series of scales above and 4 series below lateral line, body depth 32.3-36.1% of SL, and absence of filamentous rays in the first dorsal and anal-fin rays. Jupiaba paranatinga, new species, is described from rio Teles Pires, tributary of rio Tapajos. It is distinguished by having 34-35 lateral line scales, two vertically elongated humeral blotches, a conspicuous caudal spot at the end of the caudal peduncle, extending over 8-10 median caudal-fin rays, eye diameter 43.7-46.9% of HL, and relatively low body depth (31.3-35.5% of SL). Additionally, comments on the putative relationships of the new species with their congeners and an updated key to the species of the genus are provided.

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Microplastics are omnipresent in the oceans and generally have negative impacts on the biota. However, flotsam may increase the availability of hard substrates, which are considered a limiting resource for some oceanic species, e.g. as oviposition sites for the ocean insect Halobates. This study describes the use of plastic pellets as an oviposition site for Halobates micans and discusses possible effects on its abundance and dispersion. Inspection of egg masses on stranded particles on beaches revealed that a mean of 24% (from 0% to 62%) of the pellets bore eggs (mean of 5 and max. of 48 eggs per pellet). Most eggs (63%) contained embryos, while 37% were empty egg shells. This shows that even small plastic particles are used as oviposition site by H. micans, and that marine litter may have a positive effect over the abundance and dispersion of this species. (C) 2012 Elsevier Ltd. All rights reserved.

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With the purpose of evaluating the behavior of different polymers employed as binders in small-diameter pellets for oral administration, we prepared formulations containing paracetamol and one of the following polymers: PVP, PEG 1500, hydroxypropylmethylcellulose and methylcellulose, and we evaluated their different binding properties. The pellets were obtained by the extrusion/spheronization process and were subsequently subjected to fluid bed drying. In order to assess drug delivery, the United States Pharmacopeia (USP) apparatus 3 (Bio-Dis) was employed, in conjunction with the method described by the same pharmacopeia for the dissolution of paracetamol tablets (apparatus 1). The pellets were also evaluated for granulometry, friability, true density and drug content. The results indicate that the different binders used are capable of affecting production in different ways, and some of the physicochemical characteristics of the pellets, as well as the dissolution test, revealed that the formulations acted like immediate-release products. The pellets obtained presented favorable release characteristics for orally disintegrating tablets. USP apparatus 3 seems to be more adequate for discriminating among formulations than the basket method.

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The knowledge of the variations in the wood characteristics produced by eucalyptus trees according to age and sampling positions is essential for its proper use. This study had as objective to evaluate the influence of the age, longitudinal and radial positions on basic density and anatomical characteristics in Eucalyptus grandis wood. The trees were planted in 3x2 m spacing and fertilized with commercial fertilizers in planting, 6th and 12th months. According to basal area distribution, fifteen trees were selected (24, 36 and 72 months of age) - five trees per age. Disks at DBH position (1.3 m) were taken for fiber determination (length, wall thickness, lumen diameter and width) and vessels (tangential diameter, frequency and area occupied) and in other different sampling positions for basic density determination. Wood basic density increased from 0.43 to 0.46 g.cm(-3) as well as the trees age increases with a longitudinal variation model, characterized through a decrease in base-3m (0.42-0.49 -> 0.40-0.46 g.cm(-3)) and an increase to the top of the trunk (0.46 -> 0.54 g.cm(-3)) Fibers and vessels dimensions showed variations related to age and to pit-bark direction. Wood properties behavior and variations indicate that, until this period, the juvenile wood is being formed.

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The purpose of this study was to prepare and characterize coated pellets for controlled drug delivery. The influence of chitosan (CS) in pellets was evaluated by swelling, in vitro drug release and intestinal permeation assays. Pellets were coated with an enteric polymer, Kollicoat (R) MAE 30 DP, in a fluidized-bed apparatus and the coating formulations were based on a factorial design. Metronidazole (MT) released from coated and uncoated pellets were assessed by dissolution method using Apparatus I. Intestinal permeation was evaluated by everted intestinal sac model in rats, used to study the absorption of MT from coated pellets containing CS or not through the intestinal tissue. Although the film coating avoided drug dissolution in gastric medium, the overall drug release and intestinal permeation were dependent on the presence of CS. Thus, pellets containing CS show potential as a system for controlled drug delivery. (C) 2011 Elsevier Ltd. All rights reserved.

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The effects of laser focusing and fluence on LIBS analysis of pellets of plant leaves was evaluated. A Q-switched Nd:YAG laser (5ns, 10Hz, 1064nm) was used and the emission signals were collected by lenses into an optical fiber coupled to a spectrometer with Echelle optics and ICCD. Data were acquired from the accumulation of 20 laser pulses at 2.0 mu s delay and 5.0 mu s integration time gate. The emission signal intensities increased with both laser fluence and spot size. Higher sensitivities for Ca, K, Mg, P, Al, B, Cu, Fe, Mn, and Zn determinations were observed for fluences in the range from 25 to 60Jcm(-2). Coefficients of variation of site-to-site measurements were generally lower than 10% (n=30 sites, 20 laser pulses/site) for a fluence of 50Jcm(-2) and 750 mu m spot size. For most elements, there is an indication that accuracy is improved with higher fluences. (C) 2012 Elsevier B.V. All rights reserved.

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O trabalho tem como foco a análise do processo produtivo de painéis maciços feitos como tábuas e cavilhas de madeira ("stack-board") em uma fábrica austríaca, visando identificar seus pontos positivos e negativos e fornecer uma visão geral de algumas das principais variáveis envolvendo a manufatura desse produto.