Scielo RSS <![CDATA[Maderas. Ciencia y tecnología]]> vol. 21 num. 3 lang. en <![CDATA[SciELO Logo]]> <![CDATA[Characterization of pacific silver fir impregnated with extractives from western redcedar]]> Abstract: Alternative and higher value uses are needed for residual materials generated from wood products processing. Western redcedar sawdust contains an array of unique chemicals and has the potential to be used to alter the appearance, stability and durability of non-durable timbers. Here it was hypothesized that impregnation of Western redcedar heartwood extractives into Pacific silver fir would decrease shrinkage, hygroscopicity, and susceptibility to decay. Western redcedar hot water extracts were obtained from sawdust and used to pressure-treat Pacific silver fir blocks. Extractive impregnation enhanced the wood’s appearance and gave it a more cedar-like brown colour. Impregnated samples had reduced shrinkage, but were not as dimensionally stable as Western redcedar heartwood. Pacific silver fir blocks impregnated with water-soluble extractives were also highly susceptible to leaching, and leached samples had similar shrinkage values to untreated controls. In contrast, leaching had little effect on the hygroscopicity of the Western redcedar heartwood. Extractive-impregnated Pacific silver fir blocks had increased resistance to decay by two brown-rot fungi, and showed resistance similar to that of Western redcedar heartwood. However, leached blocks did not have the same decay resistance. <![CDATA[Energy valorization of woody biomass by torrefaction treatment: A Brazilian experimental study]]> Abstract: Brazilian productivity of eucalyptus trees is one of the highest in the world, and it has sustainable and viable conditions to supply the demand for woody biomass in a large quantity and diversity. This favorable situation makes Brazil one of the countries with the greatest potential for the production development of torrefied woody biomass on a commercial scale. Torrefaction is a mild pyrolysis applied to increase the energy quality of the feedstock. The aim of this study was to evaluate the Brazilian potential of woody biomass torrefaction for energy purposes. An experimental study was performed evaluating this thermal treatment of eucalyptus wood chips on a semi-continuous screw reactor developed by a Brazilian university. The results showed the increases in the energy quality of eucalyptus wood chips as a function of torrefaction temperature and time. This thermal treatment was technically feasible for the hygroscopicity reduction and the increases of fixed carbon and calorific values of the woody biomass. <![CDATA[Analysis of wood products from an added value perspective: The Uruguayan forestry case]]> Abstract: Uruguay has a forest resource of 1 million ha plantation of fast-growing eucalyptus and pine. Short-fiber pulp is the country second export product in value, but there is also a significant production of plywood and graded kiln-dried timber from both species, used mainly for appearance applications. However, the value chain of the wood industry is not yet fully developed, particularly for pine. This study classified different existing and potential wood products using added value as criteria, calculated at the industry level by adopting a system of inputs and outputs. Hypothetical plants to manufacture these products were technical and economically analyzed: thermally modified timber, cross laminated timber, laminated veneer lumber, pine timber, bleached Eucalyptus kraft pulp, pine bleached chemical thermo-mechanical, medium density fiberboards, oriented strand board and a power plant fueled with forest biomass. The data used for this study was obtained from the final project of undergraduate engineer students of the Faculty of Engineering, Universidad de la República, Uruguay, except for the eucalyptus pulp mill, which was proposed by the authors. The results showed that wood products obtained from logs that are the main objective of the plantation presented a higher added value than those manufactured from forest residues, thinnings or chips from the sawmilling industry. Solid wood products for appearance or structural applications are at the top of added value list, considering value added per product, unit of biomass or unit of forest land per year.The integration of the value chain of the products analyzed, linking solid wood products with panels or pulp, has the potential to boost the addition of value of the forest biomass in Uruguay. <![CDATA[Layer thickness performances of coatings on MDF: Polyurethane and cellulosic paints]]> Abstract: Furniture from wood material is exposed to various external effects. Impact has negative influence on these materials. Surface treatment is effective on wood material’s durability. This may change due to layers of paint and the property of the paint used on the material. The aim of this study is to determine the differences by investigating the deformations occurring on Medium Density Fiberboard (MDF) with various surface treatments due to impact. Determination of the deformation values were performed by pendulum hardness test and rapid deformation test on MDF using polyurethane and cellulosic paints with different number of application layers. Impact tester was used for determining the effect of rapidly deforming sudden impacts. Pendulum hardness tester was used to determine the layer hardness of the surfaces. Statistical assessment was performed for determining and revealing the impacts. As result of the study, paint type, layer thickness and the interaction between them were significant. Highest layer hardness values for cellulosic paint application type 1 and polyurethane paint type 2 were 241,667 s and 222,133 s respectively. According to rapid deformation test it was determined that polyurethane paint application had better results than cellulosic paint application. <![CDATA[Relationship between manufacturing parameters and structural properties of <em>Eucalyptus grandis</em> glued laminated timber]]> Resumen: La oferta actual de maderas uruguayas ha incentivado la producción de vigas de madera laminada encolada sin adaptar la tecnología original destinada a elementos de carpintería. La inexistencia de normativa sobre requisitos de fabricación permite producir y comercializar componentes que siendo no estructurales, son consumidos como tales por usuarios desconocedores de las características del producto. El objetivo del trabajo fue establecer la relación entre los parámetros de fabricación de madera laminada encolada de Eucalyptus grandis y sus propiedades estructurales, adaptando la tecnología en Uruguay. La metodología involucró modificar los parámetros de producción de una empresa y ejecutar ensayos de caracterización. Los parámetros adoptados incluyeron: adhesivo poliuretánico; diente estructural de longitud 15 mm; presión de ensamble de 10 MPa y de 1,2 MPa en uniones dentadas y vigas respectivamente; y control de tiempos de prensado en láminas y vigas. Los resultados de los ensayos mecánicos y de integridad de encolado indicaron que fue posible fabricar madera laminada estructural. Las propiedades de flexión y densidad de las vigas se correspondieron con las respectivas de la clase resistente GL24h de la norma europea. Estos resultados contribuyen a la redacción de una norma uruguaya de madera laminada encolada estructural de Eucalyptus grandis.<hr/>Abstract: The current supply of locally produced wood in Uruguay led carpentry manufacturers to produce glued laminated timber without technology adjustments. Lack of manufacturing standards allows producers to commercialize non-structural products that are consumed by unaware customers about risk of their use in structural applications. The aim of this study was to establish the relationship between manufacturing parameters of glulam made of Uruguayan Eucalyptus grandis, and its structural properties. Methodology involved definition of manufacturing specifications, supervision of manufacturing process and property characterization. Adopted parameters included: structural polyurethane adhesive, 15 mm-long structural tooth, assembly pressure of 10 MPa and 1,2 MPa for finger-joint and beam respectively, control of adhesive and applied pressure quantities in both lamellas and beams, and control of pressing and curing times. Results of mechanical tests and gluing integrity on lamellas and beams indicated that it was possible to manufacture structural glulam. Bending and density properties corresponded to those of GL24h of European Standard. Results from this study contribute to drafting a Uruguayan standard for Eucalyptus grandis glulam. <![CDATA[Effect of brown rot degradation on mass loss and compressive strength of Chinese poplar (<em>Populus simonii</em>)]]> Abstract: The wood of poplar species is generally perceived as susceptible to decay, however, poplar is still widely used as columns in traditional Chinese buildings. Understanding how decay affects the compressive properties of this material will help engineers better assess wood condition during routine inspection and maintenance. The effects of decay on compressive properties of Chinese poplar were explored using a brown rot decay fungus (Gloeophyllum trabeum). Changes in compression strength were fairly linear and more closely correlated with mass loss (R 2= 0,75). The results suggest that residual compressive strength could be roughly predicted using wood density as a surrogate measure. <![CDATA[A new approach to wood protection: Preliminary study of biologically synthesized copper oxide nanoparticle formulation as an environmental friendly wood protectant against decay fungi and termites]]> Abstract: Nanoparticles have addressed many challenges in science and technology and wood science research is one such field that has benefitted from application of metal nanoparticles. The metal nanoparticles that are commercially available for wood protection are synthesised by physical and chemical methods which produces toxic by-products and are expensive. The current study deals with a new approach for utilization of metal nanoparticle for wood protection in an ecofriendly and cost effective way. Metal nanoparticles were synthesised using plant extracts that are known to have wood preservative properties. The synergistic effects of the intrinsic property of plant extracts along with the biocidal property of metal nanoparticles were utilized. Copper oxide nanoparticles were synthesised using leaf extracts of Neem (Azadirachta indica), Pongamia (Pongamia pinnata), Lantana (Lantana camara) and extract of orange peel (Citrus reticulata). The effectiveness of the synthesised plant extract and copper oxide nanoparticle formulation is tested against wood decay fungi using agar mixed with the test substance. Graveyard test is employed to assess the effect of the copper oxide nanoparticle formulation against termites. Preliminary results are promising and studies are progressing to develop a stable and environmentally benign wood preservative formulation of metal nanoparticles and plant extracts. <![CDATA[Bio-coal production with agroforestry biomasses in Brazil]]> Abstract: Pyrolysis is a promising technology for thermal conversion of lignocellulosic biomasses into a higher added value fuel. The aim of this study was to analyze the potential of four agroforestry biomasses to produce energy as a raw material or as a bio-coal. In this study, slow pyrolysis was conducted in three final temperatures to evaluate the bio-coal production of four agroforestry biomasses widely available in Brazil. The biomasses used were sugarcane bagasse (Saccharum sp.), bamboo (Dendrocalamus giganteus), straw bean (Phaseolus vulgaris) and eucalypts wood chips (Eucalyptus sp.). In the first part was presented the raw biomasses proprieties, such as lignin, carbon, hydrogen and ash contents. In the second part was showed the bio-coal proprieties, such as gravimetric and fixed carbon yields, fixed carbon and ash contents. These bio-coal results were showed as a function of final temperature of pyrolysis. The best energy indicators for bio-coal production, such as fixed carbon yield, high heating value, was observed in the bamboo and eucalypts. The bagasse and straw bean biomasses have high concentrations of ash and low lignin content when compared with the other biomasses assessed and are less suitable to produce bio-coal. <![CDATA[Application of resource efficient and cleaner production through best management practice in a pallet manufacturer sawmill located in the city of Puyo-Ecuador]]> Abstract: Resource Efficiency and Cleaner Production strategies were implemented in a pallet manufacturer sawmill in order to observe their effect on productivity and the environment. The main goal was to inform Small and Medium Enterprises the advantages of a sustainable and green production and to encourage them to invest in Resource Efficiency and Cleaner Production strategies. In the context of Resource Efficiency and Cleaner Production, the Best Management Practices are the first low cost and easy to apply measures to transform the current industrial system into a more sustainable and green industrial system. A longitudinal research approach was used. The investigation was performed in three phases: diagnosis, selection of measures to overcome the identified problems, and implementation and evaluation of results. Once the wood companies’ diagnostic data was collected for three months, surveys were conducted with the managers and workers of “Maderol” which served as a pilot sawmill where the Best Management Practices were applied. A survey with closed yes/no-questions and a non-structured interview were conducted. Based on this information, Best Management Practices measures were identified and implemented for a test period of three months. Results were analyzed based on the economic data of the sawmill and a second survey after the test period. The results obtained from our study on a pallet manufacturer sawmill located in the city of Puyo-Ecuador confirm that the Best Management Practices can provide clear and specific guidance to Small and Medium Enterprises so that they can quickly improve their production efficiency and reduce their negative impact on the environment. <![CDATA[Evaluation of degradation in chemical compounds of wood in historical buildings using FT-IR and FT-Raman vibrational spectroscopy]]> Abstract: Vibrational spectroscopy approaches like FT-IR and FT-Raman, as analytical method, can be used to assess chemical changes in historical wood structures. In this study, wood samples of three historical buildings, in Gorgan, Iran, namely Tekie Estebar, Molla Esmaiel Mosque, and the Esmaieli Buildings were selected. Wood species was determined by their macroscopic characteristics which were hornbeam (Carpinus betulus), oak (Quercus castaneifolia), beech (Fagus orientalis), and elm (Ulmus glabra), as hardwood species, and yew (Taxus baccata) as a softwood species. Also, some samples of oak were collected from northern and southern sides of the Esmaieli Building in order to compare deterioration environmental factors.. The approximate assignment of the experimental bands was completed by comparing. For this purpose, the experimental bands with the calculated band frequencies of cellulose, hemicellulose and lignin. In addition, the reported assignment for softwood and hardwood was used to confirm the vibrational assignments. The results of spectroscopy revealed that biodegradation had occurred in all species. Comparison between the most important vibrational band frequencies related to carbohydrates and lignin in hardwood species suggested that degradation of carbohydrates was greater than lignin, which could be attributed to brown rot and hydrolysis. Reduction of chemical compounds in south oak samples was higher and could be associated with prevailing wind and UV ray in this side. In the only softwood species (yew), because of its highest exposure to frequent raining, deterioration was observed in both carbohydrates and lignin. <![CDATA[Colorimetry of wood from <em>Prosopis alba</em>]]> Resumen: El algarrobo blanco (Prosopis alba) se caracteriza por sus excelentes propiedades física-mecánicas en su madera, lo cual la hace muy apreciable en la industria del mueble. El color es un rasgo importante en ciertos usos de la madera, e incide en su calidad. El objetivo de este trabajo fue evaluar la variación colorimétrica de la madera entre sitios, sección y región de la madera y correlacionar parámetros colorimétricos con rasgos dentrométricos del árbol. Las muestras se extrajeron de tres rodales naturales (Los Arias, Santiago del Estero; Isla Cuba, Formosa y Villa Ángela, Chaco) y una plantación (San Isidro, Santiago del Estero), de la Región Chaqueña Argentina. Los parámetros colorimétricos (L*, a*, b*) se obtuvieron con un espectrofotómetro KONICA MINOLTA CM-5 con iluminante D65. El análisis confirmó que existen diferencias significativas en parámetros colorimétricos entre sitios, secciones y regiones de las muestras de madera analizadas. El tamaño de los árboles se encuentra directamente relacionado con los parámetros colorimétricos.<hr/>Abstract: The algarrobo blanco (Prosopis alba) is characterized by its excellent physical-mechanical properties in its wood. The colour is an important feature in certain use of wood, and affects its quality. The objective of this work was to evaluate the colorimetric variation between sites, section and region of the wood samples and correlate colorimetric parameters with dentrometric features of the tree. The samples were obtained from three natural stands (Los Arias, Santiago del Estero, Isla Cuba, Formosa and Villa Ángela, Chaco) and a plantation (San Isidro, Santiago del Estero), in the Chaqueña region of Argentina. The colorimetric parameters (L*, a*, b*) were obtained with a KONICA MINOLTA CM-5 spectrophotometer with illuminant D65. The colorimetric analysis confirmed that there are significant differences in colorimetric parameters between sites, section and region in the wood samples analyzed. The size of the trees is directly related to the colorimetric parameters. <![CDATA[Decay resistance of scotch pine wood impregnated with <em>Agaricus campestris</em> bio-protective extract]]> Abstract: In this study, it was investigated the possibilities of the use of fungal extract as wood protection solution against wood-degrading fungi. For that purpose, the decay resistance of Scotch pine wood samples, impregnated with Agaricus campestris fungal extract, was observed against the brown rot fungus Coniophora puteana. Impregnation procedure was applied at four different concentration levels and with two different extraction methods (hot water and methanol). The concentration levels were arranged as 1%, 3%, 5%, 7% for hot water and as 1,25%; 3,75%; 6,25%; 8,75% for methanol. The wood protective efficacy of extract solutions was determined by means of fungi decay test. The mass losses of the samples treated with both fungal extracts ranged from 3,53 to 20,91. The lowest mass losses in hot water (4,57%) and methanol extractions (3,53%) were seen in the samples treated at the highest concentration levels (7% and 8,75%). The wood samples impregnated at 7% and 8,75% concentration levels met the requirements of durability class 1 and were classified as very durable. Antifungal activity of methanol extract was stronger than that of the hot water extract. The variations which concentration levels were less than 7% did not have adequate protection to meet the requirements of the European norms. <![CDATA[Variation of green moisture content and basic density of wood in <em>Eucalyptus nitens</em> trees with sawable dimensions]]> Resumen: Se examinó la variación del contenido de humedad verde, y de la densidad básica de la madera, en fustes de árboles de Eucalyptus nitens con dimensiones aserrables, provenientes de una plantación de 18 años de edad, crecida en la región del Biobío, Chile. Se seleccionaron 9 árboles aleatoriamente. De cada árbol se obtuvo un conjunto de 8 rodelas, que representaron las siguientes alturas fijas: 0,8 m; 3,2 m; 7,0 m; 9,4 m; 15,0 m; 17,4 m; 23,2 m; y 25,6 m. De cada rodela se obtuvieron muestras al 10, 30, 50, 70 y 90% del radio, en la exposición cardinal Norte y Sur del fuste, para las determinaciones de contenido de humedad verde y densidad básica. La exposición cardinal en el fuste, resultó relevante para el contenido de humedad verde, pero no para la densidad básica. Se reportaron cambios significativos en contenido de humedad verde y densidad básica, con la posición radial y axial en el fuste. Se encontraron distintos patrones de variación radial, del contenido de humedad verde y de la densidad básica, a lo largo del fuste del árbol. Los cambios radiales (en contenido de humedad verde y densidad básica) fueron menores en la parte alta del fuste, y los cambios axiales, menores en el leño cercano a la corteza.<hr/>Abstract: In the present study, the variation of green moisture content and basic density in Eucalyptus nitens trees with sawable dimensions were examined, coming from a plantation of 18 year old, grown at the Biobío region, Chile. Nine trees were randomly selected. From each tree a set of 8 discs were obtained, which represented the following fixed heights: 0,8 m; 3,2 m; 7,0 m; 9,4 m; 15,0 m; 17,4 m; 23,2 m; and 25,6 m. From each disk samples were obtained at 10, 30, 50, 70 and 90% of the radius, in the North and South cardinal exposures, for the determinations of green moisture content and basic density. The cardinal exposure in the stem was relevant for the green moisture content, but not for the basic density. Significant changes were reported in green moisture content and basic density, with the radial and axial position in the stem. Different patterns of radial variation, of green moisture content and basic density, were found along stem of the tree. The radial changes (in green moisture content and basic density were minors in the upper part of the stem, and the axial changes were minors near to the bark.