Evaluation of Yield in Lumber of Eucalyptus for Two Sawing Models in a Portable Sawmill ABSTRACTThe present study aimed to evaluate two sawing models (radial and tangential) for Eucalyptus saligna and Eucalyptus cloeziana in a portable sawmill in order to select which one provides the highest lumber yield. To this end, twenty-four trees with 27 years of age were randomly selected: twelve of each species divided into two diameter classes, 30-34.5 and 35-39.5 cm. The trees were felled and cut in logs of 3.4 meters, and clapboards of 25 mm in nominal thickness were produced. The results obtained showed that, for both diameter classes in both species, the tangential sawing model provided higher yield compared with the radial sawing model. We conclude that lumber of satisfactory quality can be produced under the conditions studied and that these species present good potential to be used as an alternative and safe source of lumber production, being able to substitute some native species from Mozambique.
RESUMOO objetivo deste estudo foi avaliar a qualidade da casca e da madeira de Eucalipto para carbonização em indústria siderúrgica. Foram utilizadas Eucalyptus globulus, E. viminalis, E. dunnii, E. robusta, E. phaotrica, E. deanei, E. pellita, E. grandis e E. saligna, das quais foram selecionadas três arvores de cada espécie para coletas de amostras da casca e da madeira para determinação da massa específica aparente, poder calorifico e análise química imediata. Na casca, E. phaotrica apresentou maior massa específica aparente (0,418 g cm ) e maior poder calorífico (4669,667 kcal kg -1 ), enquanto que E. deanei, E. viminalis, E. globulus, E. robusta, E. grandis apresentaram maiores teores de cinza com 14,064; 8,050; 7,469; 6,438 e 6,270% respectivamente. Na madeira, E. saligna apresentou maior massa específica aparente (0,652 g cm), e o poder calorífico teve uma variação de 4468,333 kcal kg -1 para 4820 kcal kg -1 em E. viminalis e E. pellita respectivamente, com baixos teores de cinza. Tanto a casca como a madeira das nove espécies de eucalipto possuem potencial para serem usadas para produção de carvão vegetal.Palavras-chave: massa específica; poder calorífico; teor de carbono; teor de cinza; teor de voláteis Quality of the bark and wood of nine Eucalyptus species for the charcoal production ABSTRACTThe aim of this study was to evaluate the quality of bark and wood of the Eucalyptus for carbonization in the steel industry. Eucalyptus globulus, E. viminalis, E. dunnii, E. robusta, E. phaotrica, E. deanei, E. pellita, E. grandis and E. saligna were used, from which three trees of each species were selected for sampling of bark and wood for determination of the apparent specific gravity, calorific value and the immediate chemical analysis. In the bark, E. phaotrica showed higher apparent specific gravity (0.418g cm -3 ) and higher calorific value (4669.67 kcal kg -1 ), whereas E. deanei, E. viminalis, E. globulus, E. robusta, E. grandis showed higher ash content with 14.064; 8.050; 7.469; 6.438 and 6.270% respectively. In the wood, E. saligna showed higher specific gravity (0.652 g cm -3 ), with calorific value ranging from 4468.333 kcal kg -1 to 4820 kcal kg -1 in E. viminalis and E. pellita respectively, with low ash content. Therefore, both the bark and the wood of the nine eucalyptus species has the potential to be used for the charcoal production for steel industry.
<p class="Resumo">Este trabalho teve por objetivo avaliar as propriedades físicas da madeira de <em>Pinus patula</em>, com 38 anos, oriundos de um povoamento florestal de Moçambique, localizado no município de Machipanda. A determinação das propriedades físicas como a massa especifica básica, retratibilidade e umidade da madeira, no sentido medula-casca, seguiram as recomendações da Norma Panamericana - COPANT. Os resultados evidenciaram diferença estatística, ao nível de 5% de significância, no sentido radial para o coeficiente de retratibilidade. Os valores de retratibilidade foram de 6,06 e 8,80% no lenho juvenil e 6,18 e 8,65% no lenho adulto no sentido radial e tangencial, respectivamente, com coeficiente de anisotropia de 1,43 no lenho juvenil e 2,44 no lenho adulto. A madeira de <em>Pinus patula</em>, plantado na floresta de Inhamacari, apresenta uma madeira estável aos 38 anos de idade, que pode ser aplicada para fins estruturais e para a fabricação de artigos de carpintaria e móveis.</p>
This research aimed at evaluating the quality of bonded joints of Eucalyptus wood by using different faces and adhesives to produce EGP (Edge Glued Panels). Glue line shear specimens were obtained from bonded joints glued with PVAc (Polyvinyl Acetate) and EPI (Emulsion Polymer Isocyanate) adhesives, using pieces oriented with tangential, radial and intermediary faces, as well as the combination between them. The specimens were submitted to two pretreatments in order to simulate the use of joints in dry and wet environments. For shear tests, 12 treatments were obtained. The results indicated that the use of tangential x tangential and tangential x intermediary bonding faces and EPI adhesive presented better glue line shear strength for EGP in dry and wet pretreatments, respectively. The joints bonded in the radial x radial direction presented statistically inferior values when compared to the other treatments.
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