Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Since staple is the most used fastener in furniture frame, its holding capacity in solid wood joints is need to be known. Therefore, lateral shear resistance capacity of one stapled and one-row multi stapled joints constructed from Scotch pine, alder, and beech were investigated. Results showed that the joints constructed from beech with a density of 0,54 gr/cm3 yielded 4893 N, the 4 staples joints constructed from alder with a density of 0,51 gr/cm3 yielded 4487 N, and the 4 staples joints constructed from Scotch pine with a density of 0,45 gr/cm3 yielded 3498 N. Three and two staples connected joints also indicated decreasing trend when changing wood from beech to alder and Scotch pine. Results also indicated that increasing number of staple from 2 to 4 in one-row joints increased force of the joints. Two prediction formulas were derived to predict the shear of one-row multi stapled wood joints. Both formulas yielded remarkable results compared to actual laboratory test results.

En el presente estudio se investigaron las relaciones entre la velocidad de la onda acústica obtenida en árboles en pie (VÁRBOL), y la obtenida en trozas (VTROZA), con distintas características de la madera, en 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. En cada árbol seleccionado se determinó la VÁRBOL en las exposiciones cardinales Norte, Sur, Este y Oeste del fuste. La VTROZA se midió en trozas de 2,4 m de largo, centradas en longitud; a la altura fija de 2 m y al 33 %, 66 % y 100 % de la altura comercial del árbol. Para cada troza se obtuvo el contenido de humedad verde (CHv), la densidad verde (Dv), la densidad básica (DB), el módulo de elasticidad dinámico (MOEd), el indicador de la tensión de crecimiento (GSI), el módulo de elasticidad en tensión (Et) y las tensiones de crecimiento longitudinales (σL). No hubo correlaciones significativas entre la VÁRBOL y las distintas características examinadas en la madera (CHv, Dv, DB, GSI, Et y σL). La velocidad de la onda acústica en trozas (VTROZA), cambió significativamente con la posición de la troza en el fuste, aumentando en dirección base – ápice. La VTROZA se correlacionó significativamente con distintos parámetros de calidad de la madera; ésta variable podría ser utilizada para clasificar trozas con un mayor módulo de elasticidad en tensión (Et), un menor contenido de humedad verde (CHv), y una menor densidad verde (Dv).

This study aimed to analyze the glue line thickness effect and its relation with density and anatomical characteristics of eucalyptus wood. Thus, the thickness of main and secondary glue lines was measured as well as their interaction with apparent density of elements glued with resorcinol-formaldehyde (RF) and castor oil polyurethane (CP) adhesives. Anatomical wood characterization of Eucalyptus grandis × E. urophylla was performed by correlating glue line thickness. According to normative instruction, specimens were produced for delamination tests. The experiment was conducted in a completely random 2 × 2 design factorial scheme (two classes of wood apparent density and two adhesives). Pearson correlation (t < 0,01) was performed among variables. It was found that there was adhesive penetration into vessels and rays of wood. Glue line thickness was higher in woods with density higher than to 0,58 g∙cm-3 glued with RF adhesive. There was a low correlation between wood density and vessel diameter to main and secondary glue lines (t < 0,01).

The basidiomes production of two strains of Pleurotus ostreatus (one native from Patagonia, Argentina, isolated from the conifer Araucaria araucana and the other one a commercial strain) grown in different agricultural and forestry wastes was studied. The ability of the native strain generates interest to know its degradative capabilities for its use with conifer waste from the regional forest industry, which is dominated by the use of exotic Pinus species. In addition, white poplar (Populus alba), southern beech (Nothofagus pumilio), wheatgrass (Thinopyrum ponticum) and residues from beer brewing were also explored as substrates. The native strain showed better productivity of basidiomes with a biological efficiency of 17,86 % ± 3,74 % on pine wood shavings in comparison with the commercial strain used as control. The best substrates were poplar and wheatgrass with biological efficiency between 35,28 % to 88,5 % and 27,84 % to 84,01 %, respectively. Supplemented substrates showed better productivity than those without supplement. The low biological efficiency on pine could be attributed to the aromatic compounds contents because, in growth test, the diameter of the fungal colony was affected negatively by the addition of pine resin volatiles, mainly with α-limonene and δ-3-carene. In spite of the low biological efficiency, promising inter-breeding or hybrids generation could improve yields in future assays.

Even in dry state, wood can be prone to biological degradation. Preservation is a prerequisite to confer protection and durability to wood. This is conventionally achieved by impregnating the wood with pesticides. A key point in these treatments is the complex process of wood penetrability. We focused on the relation between the penetration of wood preservatives, wood microstructure, and the physical characteristics of formulations in the impregnation of the easily impregnable pine (Pinus sylvestris), and the refractory spruce (Picea abies). In this work, specimens from the two species were impregnated with three types of commercial bio-based emulsion gels formulations containing insecticides and fungicides. The effect of treatment method using dipping, surface spraying, and vacuum-impregnation, on the retention of the active agents was analyzed. Visual assessment, and qualitative and quantitative analyses of cypermethrin, permethrin and  propiconazole by gas liquid chromatography coupled to mass spectroscopy showed enhanced penetration of the active agents, and revealed differences of penetration performance of each agent. The suitable combinations of solvents and surfactants used in the bio-based formulations enabled rapid wood penetration and high yields retention. The capacity of penetration and retention of our gel formulations is discussed in terms of the connectivity of the conducting cells network of the two wood species.

To achieve sustainable development, coherence of three key elements is necessary: economic growth, social inclusion and environmental protection. They are interconnected and all are extremely important for achieving the well-being of individuals and entire societies. One of the key drivers of sustainable economic growth is the furniture industry, which is related to the maximum optimization of production cost while maintaining the high quality of the offered products. However, the expected material deficit may contribute to a significant weakening of growth dynamics. One of the possible solutions to this problem is harvesting timber from plantations of fast-growing trees that could supplement the increasing deficit of wood raw material. The research aimed to determine the cost-effectiveness of particleboard technology modification involving the change in the structure of raw material by introducing wood from fast-growing tree plantations. The research included an estimation of the unit cost of 1 m3 particleboard manufactured in the series production process. The analysis was carried out on the example of one of the leading particleboard suppliers for the Polish furniture industry and consisted in comparing the cost of production of particleboards based on wood from fast-growing tree plantations with the cost of particleboards, which are commonly available on the market. Three variants of the diversified raw material structure were taken into account: 100 % share (1), 50 % share (2) and 25 % share (3) of raw material from fast-growing tree plantations. The time range of the studies was adopted for the years 2014-2020. The research indicates that the introduction of wood from fast-growing tree plantations into the production of particleboards enables the production of material and energy cost savings at the level of 6 % (3rd variant) to even 17 % (1st variant). Variant 1 of material structure can lead to cost reduction at the level of EUR 11,6 million (in case of particleboards production capacity 570000 m3).  

The objective of this research was to evaluate the physical-mechanical properties of wood-cement boards produced with waste particles of Pinus spp. and sufficient levels of pozzolans to assimilate all Ca(OH)2 produced during the hydration reactions of Portland cement. The pozzolans used were: silica fume, metakaolin, rice husk ash, and calcined ceramic waste. The values of the pozzolans were determined based on the theoretical determination of the Ca(OH)2 content produced by the hydration reactions of Portland cement. The pozzolanic activity index was determined by the modified Chapelle test, according to NBR15895:2010 and NF18-513:2010 standards. The boards were produced through cold compression, and the test specimens were produced and tested for physical and mechanical properties at 28/91 days of curing, according to ASTM-1037:2012, EN-317:1993, NBR-9778:2005 and ASTM-642:2002 standards. The minimum values employed in the Bison® commercial process were used as reference for the physical-mechanical characterization. The boards produced presented good physical-mechanical properties even with high levels of replacement of cement by pozzolans. These properties were similar to the ones presented by the reference boards, despite the significant reduction in the specific mass of the prototype boards, which demonstrates the technological possibility of use of these materials in the production of wood-cement boards.

In this study, three-layer low-density (about 400 kg/m3) particleboards consisting of a mixture of wood particles and expanded polystyrene (EPS) were manufactured. EPS bead was incorporated in the core layer as a light filler. The influence of EPS content (0 %, 2,5 %, 5 %, 7,5 %, 10 % and 12,5 %) and press temperature (110 °C and 140 °C) on the microstructure, density profile, bending properties, internal bond and thickness swelling of the panels was investigated. Results showed that incorporation of EPS beads filled in the voids between wood particles, improved the core layer integrity, and generated a more pronounced density profile. Consequently, the bending properties and internal bond of panels adding EPS were remarkably improved, and the thickness swelling was decreased. However, the variation of the amount of EPS from 2,5 % to 12,5 % had no significant effect on the bending properties and thickness swelling. Comparing the two press temperatures, although higher temperature (140 °C) was more favourable in control panels without EPS as filler, it had a negative effect on the properties of panels with addition of EPS filler, especially for high EPS contents (10 % and 12,5 %), attributing to the shrinkage of EPS bead under press temperature that is much higher than its glass transition temperature (104 °C).

This study aimed to investigate the effect of thermal modification and nano-zinc oxide (nano-ZnO) particle impregnation on the deterioration of Caribbean pine wood under field conditions. Samples were thermally-modified at various temperature levels (control, 180 °C, 200 °C, and 220 °C). Nano-ZnO impregnation was done with an aqueous solution at 1,5 % in an autoclave under two-steps of pressure and vacuum. Unmodified and thermally-modified, non-impregnated and nano-ZnO-impregnated samples were exposed to deterioration for five months in field tests. A deterioration index was used to evaluate the health condition of the samples. The mass loss and occurrence of termite tunnels in percentage were also determined. The nano-ZnO impregnation improved the resistance of unmodified wood to field-deterioration. The thermal modification at 180oC and 200ºC increased the wood deterioration and nano-ZnO impregnation did not improve their resistance. Unmodified and 220 ºC-modified samples had lower mass loss by xylophages than other thermal treatments regardless of the nanoparticle impregnation. The nano-ZnO impregnation decreases the occurrence of termite tunnels in unmodified, 200 ºC and 220 ºC-modified samples.

El presente estudio se basa en la determinación de procedimientos adecuados para los procesos de transformación de la materia orgánica por acción de operaciones de pirolisis rápida y lenta. La fabricación controlada del biochar permite obtener un producto que cumpla características que benefician a la producción agropecuaria, permitiendo la germinación de semillas, mejorando la estructura de los suelos y además con potencialidades muy amplias en la remediación ambiental. La investigación generó biochar de biomasa residual de la especie eucalipto (Eucalyptus globulus) a partir de ramas y cortezas, mediante dos métodos pirolíticos: uno de forma rápida en horno de pirólisis con doble cámara y el otro de forma lenta, realizando el proceso bajo tierra. El trabajo desarrollado validó los dos procedimientos de obtención del biochar de eucalipto y el diseño de un horno pirolítico, estableciendo parámetros de rendimiento y temperaturas óptimas de pirólisis. El análisis de los resultados, muestra un biocarbón con amplias capacidades de utilización tanto en la aplicación al suelo como en la remediación ambiental. Para aceptar la calidad del biochar obtenido y las dosis efectivas que no ocasionen fitotoxicidad, se realizaron pruebas de germinación en semillas de maíz.