Revistas Universidad del Bío-Bío
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Influences of oak utilization on the medium density fiberboard properties
Full text linkSoftwoods are the basic and traditional raw materials for medium-density fiberboard production. However, sustainable consumption of wood material in the production of wood-based products requires material variety. Therefore, the usability of hardwood species in the production and its effects on the board properties should be of interest. Considering this, the influence of oak utilization percentages (30 %, 50 %, 70 %, and 100 %) on the physical (density, thickness swelling-TS 2 and 24 h) and mechanical (modulus of rupture, modulus of elasticity, internal bonding, screw holding resistance, and Janka hardness) properties of medium density fiberboard was evaluated in this study. Boards were factory-made instead of laboratory-made using Quercus petraea (oak), Fagus orientalis (beech), and Pinus sylvester (Scots pine) fibers. According to the results, the modulus of rupture, modulus of elasticity, and Janka hardness values were increased when medium-density fiberboard was produced using only oak fiber. On the contrary, thickness swelling, screwholding resistance, and internal bonding properties were decreased
Anatomy based papermaking potential of some woody plants under different ecological conditions
Full text linkThe increasing use of wood in the forest industry and reduction of forest resources have prompted the pa- per industry to look for new materials. To this end, this study examined the biometric coefficients of the seven woody stems grown in different regions and investigated suitability for papermaking as an alternative to the use of wood. Wood samples of each species were collected from two different regions in Türkiye: the Kozan region, which has a Mediterranean climate, and the Yuvacık region, which has a mostly oceanic climate. The species included in the study were Phillyrea latifolia (mock privet), Arbutus andrachne (greek strawberry tree), Erica arborea (tree heath), Spartium junceum (spanish broom), Laurus nobilis (bay tree), Pistacia tur- pentine (cyprus turpentine tree), and Rhus coriaria (elm-leaved sumac). All fibers were classified as short. The longest fiber was observed for Spartium junceum (spanish broom) in Kozan. The fiber diameter was highest for Arbutus andrachne (greek strawberry tree) from Kozan, followed by Rhus coriaria (elm-leaved sumac) from Yuvacık and Laurus nobilis (bay tree) from Kozan. The fiber dimensions and the relationship between them were statistically analyzed. These included the slenderness ratio, flexibility coefficient, Runkel ratio, rigidity coefficient, Luce’s shape factor, F-factor, and Muhlsteph ratio. Although differences in fiber properties were detected between the two regions, it was determined that these were not enough to affect the desired properties for paper production. It was concluded that the fibers could be used in pulp, paperboard, and corrugated board production when mixed with long fibers
Territorios de Agua y Arena. La configuración del territorio huave entre el tiempo y el espacio en San Mateo del Mar, Oaxaca, México
Full text linkA aldeia Huave de San Mateo del Mar, Oaxaca, está localizada em um banco de areia dentro da área lacustre do Istmo de Tehuantepec. A partir de uma abordagem metodológica horizontal, por meio da teoria fundamentada, foram identificadas várias categorias, uma das quais é o território, que, com base em sua geografia lacustre, deu origem a um tecido tangível e intangível entre o tempo e o espaço, por meio das relações entre água, areia, ventos e estrelas, criando uma cosmovivência e convivência que ainda hoje persiste, que se manifesta no habitar por meio da pesca, dos festivais e da moradia. Em situações muito particulares dessa cultura, entidades naturais transformam o território e permitem nomear paisagens ancestrais de poética sublime. Esse modo de habitar entre a água e a areia é a materialização dos processos de territorialização de uma cultura como a dos Huave/ikoots.The Huave town of San Mateo del Mar, Oaxaca, is located on the sand bar in the Tehuantepec isthmus's lagoon area. Diverse categories were identified using a horizontal methodology approach and grounded theory. One of them is the territory, which, from its lagoon geography, gave rise to a tangible and intangible fabric between time and space through the relationships between water, sand, winds, and stars, creating a cosmo-existence and conviviality that persists today, manifesting itself in living through fishing, partying, and housing. These are particular situations of this culture that, through the natural entities, transform the territory and allow the naming of ancestral landscapes of the poetic sublime. This way of living between water and sand is the materialization of a culture's territorialization processes, particularly the huave/ikoots.El pueblo huave de San Mateo del Mar, Oaxaca, está ubicado en la barra de arena dentro de la zona lagunar del istmo de Tehuantepec. Desde una aproximación de metodología horizontal, a través de la teoría fundamentada se identificaron diversas categorías y una de ellas es el territorio, que, a partir de su geografía lagunar, dio origen a un tejido tangible e intangible entre el tiempo y el espacio, a través de las relaciones entre el agua, la arena, los vientos y las estrellas, creando una cosmovivencia y convivialidad que aún persiste en nuestros días, y que se manifiesta en el habitar a través de la pesca, la fiesta y la vivienda. En situaciones muy particulares de esta cultura, entidades naturales transforman el territorio y permiten nombrar paisajes ancestrales de sublime poética. Esta manera de habitar entre el agua y la arena es la materialización de los procesos de territorialización de una cultura como la huave/ikoots
Thermal modification of fast-growing Firmiana simplex wood using tin alloy: Evaluation of physical and mechanical properties
Full text linkWood is an important structural material, but some undesirable properties limit its application in construction. This study investigated the effect of tin alloy thermal modification (TTM) on selected physical and mechanical properties of Firmiana simplex (Chinese bottletree) wood. Tin alloy thermal modification of F. simplex was performed in a tin alloy bath at two different temperatures (150 oC and 210 oC for 2 h and 8 h). Physical properties such as swelling, water absorption and density and mechanical properties like modulus of elasticity, modulus of rupture, impact bending, compression strength and Brinell hardness of tin alloy thermal modified and control samples were evaluated. The results showed that tin alloy thermal modification decreased the swelling of the wood to 4,85 %, 1,45 % and 6,99 % along the tangential, radial and volumetric coefficient and water absorption and density decreased to 53,10 % and 290 kg/m3 respectively compared to the control. Modulus of elasticity, modulus of rupture, impact bending, compression strength and Brinell hardness of tin alloy thermal modified F. simplex at 210 °C for 8 h decreased to 6366,1 MPa, 54,9 MPa, 2,7 MPa, 29,4 MPa and 1113,5 MPa respectively compared to the control. In conclusion, the tin alloy thermal modified wood at 210 oC significantly affected the physical and mechanical properties of the wood
LA PLURIVERSIDAD, COMPLEJIDAD Y LOS APORTES PARA LA RESOLUCIÓN DE PROBLEMAS
Full text linkEste trabajo busca desarrollar los conceptos de pluriversidad, complejidad y la ontología del Itxofill mogen. La pluriversidad es un cuerpo de saberes reconocidos a partir de la filosofía del sur que incluye todos los conocimientos de los mundos indígenas, afro, cimarrones, que fueron excluidos de la cultura europea, que fueron objeto de violencia epistémica producto del colonialismo y la exclusión de la academia. Respecto de la complejidad, uno de los grandes pensadores como es Morin propone una nueva manera de pensar sobre la naturaleza y los fenómenos, para abordar los problemas contemporáneos que no pueden ser comprendidos ni resueltos adecuadamente desde un enfoque reduccionista y lineal. Finalmente, la ontología del itxofill mogen que significa ‘de todo tipo, sin excepción’ (adverbio), mogen ‘vida’, la que corresponde a una categoría filosófica empleada para reconocer la vida de la tierra y su interdependencia con lo existente. Todas las vidas existentes en la tierra, dan cuenta de una diversidad de seres que son corpóreos, tangibles y materiales, pero al mismo tiempo son incorpóreos, energéticos y espirituales. Estos conceptos representan un gran desafío para las universidades, ya que es allí donde deben abrirse las puertas a la pluralidad de conocimientos existentes para atender la complejidad de problemas que conduzcan a detener las violencias contra la Madre Tierra, contra las mujeres, contra el racismo y contra la violencia epistémica.This paper seeks to develop the concepts of pluriversity, complexity and the ontology of Itxofill mogen. Pluriversity is a body of knowledge recognized from the philosophy of the south that includes all the knowledge of the indigenous, Afro, and Maroon worlds, which were excluded from European culture, which were subject to epistemic violence as a result of colonialism and exclusion from the academy. Regarding complexity, one of the great thinkers such as Morin proposes a new way of thinking about nature and phenomena, to address contemporary problems that cannot be adequately understood or resolved from a reductionist and linear approach. Finally, the ontology of itxofill mogen meaning 'of all kinds, without exception' (adverb), mogen 'life', which corresponds to a philosophical category used to recognize the life of the earth and its interdependence with the existing. All existing lives on earth account for a diversity of beings that are corporeal, tangible and material, but at the same time are incorporeal, energetic and spiritual. These concepts represent a great challenge for universities, since it is there where they must open the doors to the plurality of existing knowledge to address the complexity of problems that lead to stop violence against Mother Earth, against women, against racism and against epistemic violence
Surface changes in wood submitted to thermomechanical densification
Full text linkIdeal thermomechanical treatment conditions that reduce roughness and increase hydrophobicity of the wood surface require further investigation. In this study, a thermo-mechanical densification process was applied to Gmelina arborea (gamhar) wood. Three temperatures were used (140 °C, 160 °C and 180 °C) and two compaction rates (20 % and 40 %), applied for 30 minutes in a hot hydraulic press with final pressure of 2,5 MPa. Chemical changes, wettability and surface roughness of control and densified samples were investigated, as well as morphological changes. Densification partially degraded the hemicelluloses. Consequently, the wettability of the tangential surface of the densified wood decreased, with a more hydrophobic surface. Similarly, densification reduced surface roughness, especially when filtering was used for natural wood structures, with morphological changes on the surface of the densified samples. Densification with the highest temperature (180 °C) and 20 % compaction created the most hydrophobic surface (>90 °). In contrast, densification with the lowest temperature (140 °C) and compaction of 40 % provided the best results of the roughness parameters, with significant reductions, making it an applicable technique to minimize the roughness of wood in general and improve surface quality.
Efecto del aprovechamiento forestal en la formación de madera en árboles remanentes de Abies religiosa
Full text linkEl manejo forestal puede modificar la estructura y la calidad de la madera. En este estudio se evaluó el efecto de un aprovechamiento forestal sobre la formación de madera en árboles remanentes. En un bosque de Abies religiosa (oyamel) intervenido con un aclareo del 50 % de área basal durante 2014, se inventariaron 10 sitios de muestreo (1000 m2). Se analizaron mediante técnicas dendrocronológicas 80 núcleos de crecimiento provenientes de 40 árboles remanentes. Se evaluó la microdensidad y las características celulares de la madera tardía. Los anillos de crecimiento de Abies religiosa (oyamel) presentaron una buena delimitación entre madera temprana y madera tardía en la cronología de 90 años desarrollada. El aprovechamiento forestal incremento en 42,4 % el ancho de anillo; la microdensidad varió de 189 kg·m-3 a 417 kg·m-3 ( = 335 kg·m-3); las traqueidas presentaron una disminución de 8,02 % en el espesor de la pared celular y el diámetro del lumen aumento un 29,8 %. Se identificó una fila de canales traumáticos fechada en 2014, posiblemente relacionados con el estrés de la corta. Las modificaciones en la anatomía de la madera causaron una variación en la microdensidad de la madera, que repercute en la cuantificación volumétrica y de biomasa a nivel del rodal
The wide variation of amazonian stocked hardwoods affecting natural resistance to arboreal termites over time
Full text linkAfter forest suppression in mining areas, deterioration of stocked tropical hardwoods occurs at different rates and levels. Prioritizing logs to avoid wastage is challenging because the wide interspecific variability of wood traits makes natural resistance unpredictable. This work aimed to compare the biodeterioration of four Amazonian hardwoods from a mining stockyard to arboreal termite attacks over six weeks under laboratory conditions. The woods' chemical composition, anatomy, basic density, and crystallinity were determined. Mass loss and visual diagnosis of the specimens supported the biodegradability analyses. The species showed a wide range of mass loss after six weeks: Jacaranda copaia (pará-pará) - 15,2 %; Pseudopiptadenia suaveolens (timborana) - 0,8 %; Aegiphila integrifolia (tamanqueira) - 5,2 %; and Euxylophora paraensis (pau amarelo) - 0,5 %. Biodegradation did not stabilize over time for the lowest-density species. The crystallinity indicated the initial degradation of amorphous wood components, followed by a non-selective feeding mechanism. Gathering all species, increased extractive and lignin levels, fiber wall thickness, and basic density favored the natural wood resistance, oppositely to large vessel elements. The much lower basic density of J. copaia explains its lowest natural resistance. Wall thickness, pore diameter, and density overcame chemical composition on wood biodegradability. Low-density hardwoods stocked in mining yards are a priority for proper destinations.
Reconocimiento de luz y comportamiento térmico en la estructura y función del cazador de viento Baber en la arquitectura vernácula de Bandar Lengué
Full text linkLa ciudad portuaria de Bandar Lengué se ubica en una región con un clima cálido y húmedo, en el sur de Irán. Como resultado, y dada la inclemencia del clima, se han desarrollado múltiples elementos y espacios para crear un tipo especial de arquitectura sostenible: un cazador de viento Baber. Ya que no hay evidencia de ningún estudio científico relacionado con esta infraestructura, o con su análisis, esta investigación se ha realizado en dos partes, estructural y funcional, para entenderlas mejor como una estructura estable. Para este examen se escogió el área de Bandar-Lengué (36 casas con 70 años de antigüedad o más) para un estudio cualitativo (presentando al cazador de viento Baber, sus componentes, materiales y proceso de construcción, las áreas ocupadas, la orientación y su posición) y cuantitativo (medición de luz usando el software de análisis Ecotec y mediciones de temperatura con un dispositivo “Fluke T3000c”). Esto se realizó en un momento en el que el aire acondicionado mecánico no era el estándar, para ver si estas habitaciones podían satisfacer las necesidades de los habitantes como un aire acondicionado natural.Bandar-Lengeh is located in a region with a hot and humid climate in the south of Iran. As a result, given its harsh weather conditions, several elements and spaces have been devised to create a special kind of sustainable architecture, a Baber-Room. Since there is no evidence of any scientific study regarding Baber-Rooms or their analysis, this research has been conducted in two parts, structural and functional, to better understand them as a stable structure. To examine these, an area of Bandar-Lengeh was chosen (36 houses aged 70 or above) for a qualitative (introducing the Baber-Room, its components, materials, and construction process, the occupied areas, orientation, and positioning) and a quantitative study (light-measurement using Ecotect analysis software and temperature measurements with a “Fluke T3000fc” device). This was done at a time when mechanical air-conditioners were not standard, to see whether these rooms could meet the needs of inhabitants as natural air-conditioners.Bandar-Lengeh está localizada em uma região de clima quente e úmido no sul do Irã. Como resultado, dadas as condições climáticas adversas, vários elementos e espaços foram planejados para criar um tipo especial de arquitetura sustentável, uma Baber-Room. Como não há evidências de nenhum estudo científico sobre as Baber-Rooms ou sua análise, esta pesquisa foi conduzida em duas partes, estrutural e funcional, para melhor compreendê-las como uma estrutura estável. Para examiná-las, foi escolhida uma área de Bandar-Lengeh (36 casas com idade igual ou superior a 70 anos) para um estudo qualitativo (apresentando a Baber-Room, seus componentes, materiais e processo de construção, as áreas ocupadas, a orientação e o posicionamento) e um estudo quantitativo (medição de luz usando o software de análise Ecotect e medições de temperatura com um dispositivo "Fluke T3000fc"). Isso foi feito em uma época em que os condicionadores de ar mecânicos não eram padrão, para verificar se essas salas poderiam atender às necessidades dos habitantes como condicionadores de ar naturais
