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

This work addresses the development of research competencies on teacher’s own professional practices in Visual Arts. The use of Arts-based Research (ABR) methodology promotes the relationship between the role of the teacher and that of the artist and researcher. It also demands that initial teacher formation in Arts provide teachers with research tools so that their professional duties are enhanced and strengthened. In- and out-class research fosters both self-reflection and enquiry capacities about teacher’s own pedagogical practices. In this regard, the use of ABR in a formal education context at the Hispanoamerican School in Santiago de Chile contributed indeed to fostering meaningful learning about teachers’ and students’ artistic experiences at school.

The purpose of this article is to focus on the various pedagogical and social dimensions that vertebrate service-learning projects, a multidimensional and interdisciplinary subject of study. From the dissection of the approaches of recognized authors in the Ibero-American field, a panoramic vision of each of the regularities is offered: learning, service, participation, reflection, educational intentionality, among other dimensions that are woven together by the projects. These regularities serve to identify the signs of identity of these practices, as well as the similarities and differences they maintain with other experiential practices and with other educational methods.

El estudio titulado: “Libérate” en el afrontamiento al estrés en mujeres con problemas de fertilidad de Trujillo, tuvo como propósito conocer la influencia del taller “Libérate” en el afrontamiento al estrés en mujeres con problemas de fertilidad de Trujillo. Se desarrolló bajo el enfoque experimental de diseño cuasi experimental, se trabajó con una población de 24 mujeres con problemas de fertilidad, contando con una muestra de 12 mujeres con problemas de fertilidad de un centro de reproducción asistida de Trujillo, siendo seleccionadas por muestreo no probabilístico. Se evaluó mediante el Cuestionario de estilos de afrontamiento al estrés – COPE. De esta manera, se determinó que el taller tuvo efecto en las dimensiones de estilos de afrontamiento centrados en el problema y en la emoción en las mujeres, debido a que, luego de la aplicación del taller se obtuvo diferencia significativa (p<.05), sin embargo, en la dimensión otros estilos de afrontamiento se observó una influencia no significativa (p≥.05).

Conventional kilns dominate the wood drying industry. However, energy consumption during the process of ventilation remains a significant challenge. In this study, we designed a device to recover waste heat from exhausted wet air during kiln drying. To determine energy conservation, the device was installed in a 50 m3 kiln used for drying sawn timber in two different Chinese cities, and a traditional kiln with identical size was chosen to enable comparison. Two kinds of hardwood (Betula costata Trautv and Quercus mongolica) swan timbers were dried using conventional technology to investigate the energy saving effect of rainy seasons as well as seasonally different temperature. The results revealed that drying time and energy consumption decreased with the use of this energy-conserving device. Electrical and energy consumption were reduced by 18.9% and 38.5%, respectively. Waste heat recovery efficiencies ranged from 20.32% to 28.15%. Energy-conservation efficiency can be predicted to range from 12.23% to 22.74% annually. Equipment costs can be recovered within 3.5 years.

This paper presents results of a study on the mechanical characteristics of impregnated Jabon wood (Anthocephalus cadamba) using Merbau extractives (ME) and two types of polymerised Merbau extractives (PME), i.e PME22 and PME33. A set of tests on hardness,  shear, modulus of elasticity (MOE) and modulus of rupture (MOR) was conducted according to the relevant standards. Two types qualitative analysis by means of FTIR spectra and XRD analysis were carried out to explore relationship between the mechanical characteristics alteration with physico-chemical characteristics. The results indicated that a positive improvement in mechanical characteristics was obtained for Jabon wood impregnated with PME22 and PME33. Surface hardness of modified wood samples exhibited higher values compared to the non-impregnated samples for end and side hardness, by 20.04 and 30.54 % (PME22), and 32.73 and 39.89 (PME33), respectively. Shear strength increased by 41.87 and 49.58 % (PME22) and 74.02 and 79.10 % (PME) for radial (T) and tangential (T) sections, respectively. MOE increased by 23.52% (PME22) and by 40.12% (PME33), MOR values also increased by 28.50 and 41.19 % after impregnation with PME22 and PME33, respectively. The increment of mechanical propertiesof treated Jabon wood after impregnation treatment using polymerised Merbau extractives were confirmed by FTIR spectra and crystallinity (XRD) analysis.

In this paper, the impacts of heartwood and sapwood usage on the physical, mechanical, and surface properties and formaldehyde emission of particleboard are investigated. European Larch (Larix decidua) trees are chosen as a raw material. The logs are divided into three segments: sapwood, heartwood and total wood. The highest amounts of cellulose (51.54%), and hemicelluloses (22.24%) in the sapwood, followed by total wood, and the heartwood, respectively. However, the highest amount of lignin (30.54%) was found in the heartwood. The highest extractives values are obtained from heartwood, followed by total wood, and the sapwood, respectively. While the lowest pH value (3.03) is found in heartwood, the sapwood samples provide the highest values (4.95). The highest ash (0.49%) content and amount of condensed tannin (13.89%) are extracted from heartwood, followed by total wood, and sapwood, respectively. The test panels manufactured from sapwood have the smoothest surface (7.49 µm (Ra), 48.86 µm (Ry), and 35.12 µm (Rz)) and the lowest contact angles (67.8ᵒ), while the roughest surface (14.20 µm (Ra), 68.05 µm (Ry), and 50.02 µm (Rz)) and highest contact angle (96.9ᵒ) are obtained from the panels of heartwood. The thickness swelling (19.88%) and formaldehyde emission (7.28%) values of the panels manufactured from heartwood are significantly lower than the panels manufactured from the total wood and sapwood. The highest modulus of rupture (MOR), modulus of elasticity (MOE), and internal bond (IB) values are observed on sapwood, respectively, 15.60 MPa (MOR), 2201 MPa (MOE), and 0.523 MPa (IB). These mechanical strength values (MOR, MOE, and IB) are followed by total wood, and the heartwood, respectively. Surface smoothness and wettability of the particleboards manufactured from sapwood are better than those of total wood and heartwood.

El objetivo del presente estudio fue determinar las propiedades físicas de la madera de Guazuma crinita por el método convencional, así como estimar estas propiedades por espectroscopia infrarroja cercana (NIR) a través del desarrollo de modelos de calibración multivariada. Las muestras fueron obtenidas de tres niveles del eje longitudinal en 5 árboles para 5 y 8 años de edad seleccionados al azar de una plantación en la zona de Puerto Inca, departamento de Huánuco (Perú). Se determinó la densidad básica, contracción total volumétrica, tangencial y radial por el método destructivo o convencional. Los modelos fueron desarrollados por regresión de mínimos cuadrados parciales (PLS) mediante transformaciones matemáticas. Para la validación de los modelos se empleó un grupo de muestras que no participo en el desarrollo del modelo. Se encontró diferencias estadísticas significativas (  = 191,5; = 84,9) entre las tres alturas en el fuste. Para densidad básica y contracción volumétrica se encontró valores de  (0,88 y 0,83) y RPDp (1,55 y 3,27) aceptables para la predicción. Palabras claves: Contracción radial, contracción tangencial, contracción volumétrica, densidad básica, PLS.

In the present study, two mathematical models were developed to optimize the surface roughness for machining condition of Cedar of Lebanon pine (Cedrus libani). Taguchi approach was applied to examine the effect of CNC processing variables. Quality characteristics parameters were selected as arithmetic average roughness (Ra) and average maximum height of the profile (Rz) for wood material. Analysis of variance (ANOVA) was used to determine effective machining parameters. Developed mathematical models using response surface methodology (RSM) were optimized by a combined approach of the Taguchi’s L27 orthogonal array based simulated angling algorithm (SA). Optimum machining levels for determining the minimum surface roughness values were carried out three stages. Firstly, the desirability function wasused to optimize the mathematical models. Secondly, the results obtained from the desirability function were selected as the initial point for the simulated angling algorithm. Finally, the optimum parameter values were obtained by using simulated angling algorithm. Minimum Ra value was obtained spindle speed of 17377 rpm, feed rate of 2.012 m/min, tool radius of 8 mm and depth of cut of 2.009 mm by using desirability function based simulated angling algorithm. For Rz these results were found as 16980 rpm, 2.004 m/min, 8.001mm and 2.003 mm. The R-square values of the Ra and Rz were 95.91 % and 96.12 %, respectively. The proposed models obtained the minimum surface roughness values and provided better results than the observed values.

The common testing protocol to determine the shear strength of bamboo parallel to grain is ISO 22157.  However, widely documented limitations of this test procedure calls for an alternative testing protocol.  This study compared ISO 22157 (TP1) and 2 alternative testing protocols proposed by Base Bahay (TP2a and 2b) in determining shear strength of bamboo parallel to grain. The study used a local bamboo known as “kawayang tinik” (Bambusa blumeana). Results showed that TP1 produced more pure shear failures at 65% compared to TP2a and TP2b at 55% each.  Shear strength values between the three methods were not significantly different, although, TP2b resulted in the lowest coefficient of variation at 18%.  Also, TP2b was found to be the most effective in terms of specimen preparation, ease of assembly of testing equipment, and low variability in data. 

In this Study, Pinus massoniana wood was heat treated with silicone oil to modify the chemical composition relative to the unmodified wood. Specifically, polysaccharide, lignin, extractives and ash contents were the properties investigated. The wood samples were first of all pre-heated in a micro-wave oven for 5 minutes to ease heat transfer within the wood. Silicone oil heat treatment was carried out at 150, 180 and 210oC for 2, 4, 8 h. The silicone oil heat treated wood was characterized by Fourier transformed infrared (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and contact angle.  Results showed that silicone oil heat treatment caused significant decrease in the polysaccharide (P ˂ 0.0001) and ash contents (P ˂ 0.0001) and significant increase in the lignin (P ˂ 0.0001) and extractives contents (P ˂ 0.0001) as the treatment time increased. FTIR results showed that the chemical constituents of the wood were affected by the treatment, while TGA showed that the treated wood resulted in higher thermal stability with increase in the crystallinity index. Silicone oil heat treatment proved to be effective in increasing the contact angle of the wood.