The aim of this study was to evaluate the change in colorimetric patterns and the termite resistance of light-colored and low durability wood when impregnated with teak (Tectona grandis) heartwood extractives. Hot water and ethanol extracts were obtained from 20-year-old teak heartwood and used to evaluate the influence on color change and the natural resistance of 10-year-old teak sapwood and Pinus sp. For wood impregnation, a full-cell (Bethell) treatment was conducted. To verify the influence of the teak extracts, the colorimetric patterns of wood were determined using the Munsell and CIE-L*a*b* systems. Choice and no-choice feeding tests were performed under laboratory conditions to test the efficacy of the teak extract solutions against two termite species Nasutitermes corniger and Cryptotermes brevis. All of the extract solutions promoted a significant darkening of the wood, bringing the color of the impregnated wood closer to older teak heartwood than the untreated samples of the respective species. Ethanol extracts increased the resistance and mortality against N. corniger in both choice and no-choice tests. Resistance to C. brevis was not clearly affected.
RESUMOObjetivou-se avaliar a resistência de aglomerados confeccionados com madeira de Acacia mangium Willd. colada com adesivo à base de ureia-formaldeído e taninos a organismos xilófagos. Os painéis foram produzidos com 40 × 40 × 1,27 cm (largura × comprimento × espessura); ao adesivo, foram adicionados 10, 20 e 30% de taninos, sendo empregadas quatro razões de compactação (1,39; 1,55; 1,73 e 2,00). Nos ensaios com fungos e térmitas, utilizaram-se amostras de 2,50 × 2,50 × 1,27 cm (largura × comprimento × espessura ABSTRACTThis study aimed to evaluate the resistance of particleboards made of Acacia mangium Willd. wood, bonded with urea-formaldehyde and tannins as adhesive, against xylophagous organisms. Panels of 40 × 40 × 1.27 cm (width x length x thickness) were produced; 10, 20 and 30% of tannins were added to the adhesive; four compaction ratios (1.39; 1.55; 1.73 and 2.00) were employed. Samples of 2.50 × 2.50 × 1.27 cm (width x length x thickness) were used in the tests with fungi and termites. Gloeophyllum trabeum and Trametes versicolor (12 weeks) fungi and Nasutitermes sp. (45 days) termites were employed in the tests. Panels with the highest compaction ratio and proportion of tannins provided the most effective resistance to Gloeophyllum trabeum. No difference between the adhesives and compaction ratios was observed for Trametes versicolor. Gloeophyllum trabeum caused greater mass loss than Trametes versicolor. The samples were completely consumed by the termites.
RESUMO A avaliação da resistência natural da madeira a organismos xilófagos é de importância fundamental na escolha de espécies a serem utilizadas na construção civil e na indústria de móveis. Assim, avaliaram-se os efeitos do teor de extrativos e da densidade na resistência biológica das madeiras deAcacia mangium, Casuarina equisetifolia, Corymbia torelliana, Eucalyptus cloeziana, Tectona grandis e Caesalpinia echinata ao térmita xilófago Nasutitermes corniger, em condições de laboratório. Corpos de prova, com dimensões de 2,00 x 2,54 x 0,64 cm (radial x longitudinal x tangencial) foram retirados de cada madeira em quatro posições no sentido medula-casca (cerne interno, cerne mediano, cerne externo e alburno). As madeiras foram expostas à ação dos térmitas por 28 dias em ensaio de alimentação forçada. As amostras não selecionadas para o ensaio com os térmitas foram transformadas em serragem e os extrativos obtidos da fração que passou pela peneira de 40 e ficou retida na de 60 "mesh". A resistência natural da madeira, dentre as posições medula-casca, para as espécies estudadas, não está correlacionada com a densidade e teor de extrativos das mesmas. No entanto, entre as madeiras, aquelas com maiores densidade e teor de extrativos são mais resistentes. As madeiras com maior resistência biológica ao térmitaNasutitermes corniger (menores perda de massa, desgaste e tempo de sobrevivência dos insetos) são Corymbia torelliana eCaesalpinia echinata e a de menor resistência aCasuarina equisetifolia.
There are reports relating color to extractives, however there is a lack of information about the effect of other characteristics on the colorimetry of wood. Thus, this study aimed to evaluate the longitudinal and radial variability of color and its relationship with the basic density and extractive contents of Calycophyllum spruceanum wood from a six-year-old plantation located in Rio Branco, Acre, Brazil. The determination and assessment of the wood color were carried out by the Commission Internationale de L’Éclairage - CIE-L*a*b* system. The basic density and extractive contents were determined according to current technical standards. The species wood color was classified as yellowish olive. The highest and lowest lightness (L*) were longitudinally observed in the base (cutting height) and diameter at breast height (DBH), taken at 1.30 m from the ground. In relation to radial position, the lightness (L*) was lower in peripheral regions of the trunk. Higher concentrations of redness (a*) and yellowness (b*) and saturation (C) occurred along the DBH and the external radial position. In evaluating age, the extractive contents were not correlated to the wood color, while the basic density was correlated with a*, b*, C and h* colorimetric parameters. The colorimetric characterization of this specie contributes to its proper identification and a more homogeneous classification of lumber, and can be used from the log break-down (sawing) to its end use, adding commercial value to the wood.
ResumoÓleos de andiroba, copaíba e pinhão-manso são estudados por serem empregados em fins variados, como sabões, velas, medicamentos, biodiesel, tintas, fiação de lã e lustração de móveis. Também, são utilizados como inseticidas, fungicidas e moluscicidas. Objetivou-se neste trabalho caracterizar as propriedades físicas dos óleos de andiroba, copaíba e pinhão-manso, puros ou enriquecidos com iodo sublimado (I2) e avaliar sua eficiência contra fungos de podridão parda e branca. Os óleos de andiroba e copaíba foram oriundos de comunidades do município de Santarém (PA) e o óleo de pinhão-manso, da Fazenda Tamanduá, município de Santa Terezinha (PB). Foram determinadas as características físicas (pH, índice de acidez, viscosidade e densidade) dos óleos e realizado o ensaio de toxidez em meio de cultura com fungos de podridão parda e branca. O enriquecimento dos óleos com iodo (I2) proporcionou aumento da viscosidade. Foi constatada menor densidade para o óleo puro de andiroba e copaíba do que para o enriquecido com 5% de I2. O incremento de iodo nas soluções propiciou a diminuição de pH nos óleos de andiroba e copaíba, além do aumento do índice de acidez do óleo de andiroba. Para a avaliação da eficiência, os óleos foram empregados puros ou enriquecidos com iodo sublimado. No ensaio de toxidez em meio de cultura, para o fungo Trametes versicolor, a maior inibição em 20 dias foi para o tratamento com andiroba 1% de I2. Para o fungo Postia placenta, a maior inibição foi constatada para o tratamento com óleo de andiroba com 5% de I2. Palavras-chave: Óleos vegetais, características físicas, toxidez, fungos xilófagos. AbstractPhysical analysis and assessment of the antifungal effect of Carapa guianensis, Copaifera sp., and Jatropha curcas oils. Andiroba, or crabwood (Carapa guianensis), copaiba (Copaifera sp.) and jatropha (Jatropha curcas) oils are studied since they are used for a wide range of purposes, as soaps, candles, medicines, biodiesel, paints, wool spinning, and furniture lustration. Besides, they are also used as insecticides, fungicides, and molluscicides. The objective of this study was to characterize the physical properties of andiroba, copaíba and jatropha oils and to assess their efficiency against fungus of brown and white rot. The oils of andiroba and copaiba came from communities in the municipality of Santarém (state of Pará, Brazil), and the jatropha oil, from Fazenda Tamanduá, municipality of Santa Terezinha (state of Paraíba, Brazil). The physical characteristics (pH, acidity index, viscosity, and density) of the oils were determined, and the toxicity test was carried out in culture medium with brown rot fungi. The enrichment of the oils with iodine (I2) provided higher viscosity. It was found lower density for pure andiroba and copaiba oil than for enriched oil with 5% I2. The addition of iodine in the solutions caused the decrease of pH value in the oils of andiroba and copaiba and the increase of acidity index on andiroba oil. For the assessment of efficiency, oils were tested either pure or ...
O objetivo desta pesquisa foi avaliar a qualidade do tratamento preservativo das espécies de bambu Dendrocalamus giganteus e Bambusa vulgaris submetidas a dois métodos de tratamento. Os bambus foram colhidos em touceiras em Alegre e Jerônimo Monteiro, sul do Espírito Santo. As hastes foram seccionadas em colmos de 2,0 m de comprimento e tratadas em soluções de 1 e 3% de ingredientes ativos (i.a.) de um produto à base de cobre, cromo e boro (CCB). No método de imersão prolongada, os colmos foram imersos na solução por 5, 10 e 15 dias. No método de Boucherie modificado, a solução penetrou no bambu pela ação de uma pressão de 0,7 MPa. Foi avaliada a qualidade do tratamento por meio da penetração e da retenção do CCB nos colmos. Houve maior penetração de i.a. na base dos colmos e a retenção ficou abaixo da recomendada pela norma brasileira para tratamento de madeira.
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