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Ciencia y Tecnología http://revistas.ubiobio.cl/index.php/MCT <p>&nbsp;</p> <p>&nbsp;</p> <table style="margin-top: -250px; width: 1025px; height: 672px;"> <tbody> <tr> <td style="width: 30%;"><strong><span style="color: #ffffff; text-align: center;"><img src="/public/site/images/visepul/cover-3d-21(4).png"></span></strong></td> <td style="width: 30%;"> <div class="issueCoverDescription"> <div class="description"> <p><img style="width: 30px;" src="http://revistas.ubiobio.cl/public/site/images/visepul/pdf_icon_copy6.png" alt=""> <a href="http://revistas.ubiobio.cl/index.php/MCT/issue/view/290">Full Text PDF</a></p> <p><img style="width: 30px;" src="http://revistas.ubiobio.cl/public/site/images/visepul/e-book_full1.png" alt=""> <a href="http://revistas.ubiobio.cl/revistamadera/e-book/21.4-2019/">e-book version</a></p> <p><a href="http://revistas.ubiobio.cl/revistamadera/e-book/18.2-2016/mobile/"><img style="width: 30px;" src="http://revistas.ubiobio.cl/public/site/images/visepul/mobile2.png" alt=""></a> <a href="http://revistas.ubiobio.cl/revistamadera/e-book/21.4-2019/mobile/html5forpc.html">mobile version</a></p> <p><img style="width: 30px;" src="http://revistas.ubiobio.cl/public/site/images/visepul/2000px-Text-xml.svg_.png" alt="">&nbsp; <a href="https://scielo.conicyt.cl/scielo.php?script=sci_issuetoc&amp;pid=0718-221X20190004&amp;lng=es&amp;nrm=iso">XML</a></p> </div> </div> </td> <td style="width: 30%;"> <p>Editor-in-Chief: <a href="mailto:ananias@ubiobio.cl" target="_self">Rubén A. Ananias</a><span id="result_box" class="short_text" lang="en"><br>Technical Editor</span>: <a href="mailto:lsalvo@ubiobio.cl">Linette Salvo S.<br></a>Digital Manager: <a href="mailto:%20vsepulveda@ubiobio.cl">Victor Sepúlveda V.</a><br>E-mail :<a href="mailto:remaderal@ubiobio.cl">remadera@ubiobio.cl</a><br>E-mail :<a href="mailto:remadera.journal@gmail.com">remadera.journal@gmail.com</a><br><br>2018 Journal Impact Factors:<br> 2-years: 1.4<br>5-years: 1.5<br> Frequency: 4 issues by year.<br>January, April, July, October<br>ISSN 0718-221X online version.<br>ISSN 0717-3644 printed version.</p> </td> </tr> </tbody> </table> en-US ananias@ubiobio.cl (Ruben A. Ananias.) vsepulveda@ubiobio.cl (Victor Sepulveda Villarroel) Mon, 02 Sep 2019 00:00:00 -0400 OJS 3.1.0.1 http://blogs.law.harvard.edu/tech/rss 60 Assessment of physical and mechanical properties of papua new guinea timber species http://revistas.ubiobio.cl/index.php/MCT/article/view/3778 <p>A comprehensive testing program has been developed to assess different physical and mechanical properties of 26 commercial and lesser-known PNG species from secondary and plantation forests. The impact of log position in a tree on the mechanical properties has also been assessed to optimize the utilization of timbers along the value chain. The results showed that stiffness and bending strength tend to decrease or remain unchanged along the stem. Shear strength and Janka hardness displayed a similar trend to a lesser extent where the position in the tree had a limited impact on compression strength properties. Thus, segregating based on log position can be of interest where desired mechanical properties and costs associated with segregating justify optimum mechanical properties for the intended end use. The properties of selected species from plantations and regrowth forests were generally lower than those found in the literature for timbers from old-growth forests. The size of specimens tested, the amount and provenance of tested material, and some adaptive traits for tropical tree species are some factors potentially explaining observed differences. However, a comparison with recent studies tends to confirm the overall reduction of physical and mechanical properties when compared with old-growth forests timbers.</p> Benoit Belleville, Kilva Lancelot, Elaine Galore, Barbara Ozarska ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 http://revistas.ubiobio.cl/index.php/MCT/article/view/3778 Mon, 02 Sep 2019 00:00:00 -0400 The chemical and morphological properties of oleaster http://revistas.ubiobio.cl/index.php/MCT/article/view/3788 <p>This study investigated the morphological characteristics and chemical properties of the wood and the chemical properties of the bark of the oleaster (<em>Elaeagnus angustifolia</em>) tree, which grows in a variety of climatic conditions in different regions of Turkey. The study materials were taken from three different regions of Turkey having different climatic conditions and elevations with the aim to determine the chemical properties of the bark and wood and the fiber properties of the wood. According to chemical analyses, no significant differences in the core components of the cell wall were observed between the heartwood and the sapwood. The samples collected from the Çankırı region had the highest holocellulose content (84.9%), while the proportions of alpha cellulose (52.3%) and lignin (24.0%) in samples taken from the Balikesir region were found to be higher than in samples from the other regions. According to the sugar analysis, glucose and xylose were found to be higher in the heartwood than in the sapwood. When the sugar ratios were evaluated by region, the glucose and xylose ratios were the highest in the Çankırı region (43.7% and 22.8%) and the lowest in the Konya region (38.3% and 20.5%). When looking at the inner bark (phloem) and outer bark (rhylidome) rates, the amounts of holocellulose and alpha cellulose were higher in the inner bark and the lignin rates were higher in the outer bark. The wood solubility values for cold and hot water, ethyl alcohol and the 1% NaOH were highest in samples from the Çankırı region and lowest in those from the Konya region, whereas bark solubility rates were highest in the samples taken from the Balıkesir region. When morphological characteristics were examined, no obvious differences were seen among the regions in terms of the fiber length, fiber width, lumen diameter or double wall thickness. Upon further investigation, it was determined that the oleaster tree wood was suitable for papermaking, but that the produced paper would exhibit a low resistance value because the average felting rate among the three growing regions was low (39.87%).</p> Mehmet Akgül, Mehmet Akça ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/3788 Mon, 02 Sep 2019 00:00:00 -0400 Characterization of the wood properties of Cedrelinga cateniformis as substitute for timbers used for window manufacturing and outdoor applications http://revistas.ubiobio.cl/index.php/MCT/article/view/3820 <p><em>Cedrelinga cateniformis </em>(tornillo) is a timber species of the South American Amazon Basin. In its natural distribution area, the wood has various local uses, such as furniture, art work, door and window frames, and light construction. In order to promote this lesser known species for high valued applications on the international market, wood anatomical, topochemical and physical/mechanical studies were carried out to characterize the wood properties. The topochemical distribution of the lignin and phenolic extractives in the tissue were studied by means of cellular UV microspectrophotometry (UMSP). The results of the structural and topochemical analyses were compared with the interrelation of certain anatomical and subcellular structures as well as the chemical composition with regard to the physical and mechanical properties. The natural durability of the mature heartwood was analyzed according to the European Standards and is resulting in a durability class 1 against basidiomycetes. Based on the findings of the comprehensive investigations concerning physical and biological features, e.g. the dimensional stability and durability, <em>Cedrelinga cateniformis</em> is ideally suited as a substitute for overexploited tropical woods currently used in Europe for wooden window frames and other above ground outdoor applications and thus can contribute to increase the value-added production in Peruvian forests.</p> Volker Haag, Gerald Koch, Eckhard Melcher, Johannes Welling ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/3820 Mon, 02 Sep 2019 00:00:00 -0400 Carbon fiber-reinforced polymers as a tensile reinforcement of the Pinus elliotti and Manilkara huberi wood species http://revistas.ubiobio.cl/index.php/MCT/article/view/3829 <p>In wood structures, the elements subjected to bending stresses, such as the beams, present a fracture initiated in the tensile region, and under these conditions, the use of laminated composite materials is presented as an alternative solution in the form of repair or reinforcement. This research aimed to evaluate the influence of the use of carbon fibers laminated composites in tensile reinforcement in the direction parallel to grain of <em>Pinus elliotti </em>and <em>Manilkara huberi</em> wood species. The Viapol two-component epoxy adhesive was used in the lamination and fixation of the unidirectional carbon fiber in the wood species. Ten specimens with no defects (reference) and 10 specimens were prepared for each crack length (25 and 50mm) with and without the reinforcement (60mm × 50mm) by the laminated composite. The tensile tests were performed in accordance with the requirements of the Brazilian standard ABNT NBR 7190 (1997). From the results of the statistical analysis, the use of the carbon fiber composite was able to restore the tensile strength of the cracked samples (partial or total) in relation to samples without defects, demonstrating the potential of the laminates in carbon fibers as an alternative solution in repair for both wood species.</p> Cintia Grazielle Alves dos Santos Bravo, Luiz Antonio Melgaço Nunes Branco, Eduardo Chahud, Vinicius Borges de Moura Aquino, Alfredo Manuel Pereira Geraldes Dias, Andre Luis Christoforo, Francisco Antonio Rocco Lahr ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/3829 Mon, 02 Sep 2019 00:00:00 -0400 Effect of applying finishing products and sanding on the surface of marupa wood http://revistas.ubiobio.cl/index.php/MCT/article/view/3827 <p>The effect of applying cetol and varnish finishing products and sanding on the surface roughness and colour of marupa (<em>Simarouba amara</em>) wood was evaluated. Three coats of each product were applied and two sandpaper grits were used, 280 and 320). The analyzes were performed on untreated samples and between each coat of products in order to analyze the effect of sanding, the products and the number of coats. According to colorimetry, the L* value for the control treatment was 82.83 and the treatments reduced the L* to 61.70 on average for the cetol treatment and 77.09 for the varnish treatment, showing that the cetol darkened the wood more than the varnish. The yellowish and reddish pigmentations became more intense according to the positive values of Δa* and Δb*, especially after applying the cetol. The total colour variation ΔE average was 40.79 for the cetol treatment and 9.83 for the varnish treatment, confirming a much more significant colour change in the cetol treatment. Sanding with different grits did not significantly alter the surface colour. The product application made the wood surface smoother, and was noticeable from the second coat. Sanding reduced roughness on the wood surface, but the finishing product was the largest source of variation.</p> Marcella Hermida de Paula, Robert Rossi Silva de Mesquita, Mírian de Almeida Costa, Joaquim Carlos Gonçalez, Rubén A. Ananías, Gèrard Janin ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/3827 Mon, 02 Sep 2019 00:00:00 -0400 The influence of ultraviolet radiation on the colour of thermo-mechanically modified beech and oak wood http://revistas.ubiobio.cl/index.php/MCT/article/view/3828 <p>The study examined the influence of ultraviolet radiation on the colour of thermo-mechanically modified beech (<em>Fagus sylvatica </em>) and oak (<em>Quercus robur</em>). The wood colour parameters were measured using the mathematical CIE L*a*b* and L*C*h colour space models. The higher the temperature of thermo-mechanical treatment, the least susceptible beech and oak wood was to a change in L*, a* and b* under the influence of light irradiation. The greatest changes in the colour of non-densified and densified beech and oak wood occurred after 20 h of light irradiation. The higher the temperature of thermo-mechanical treatment, the smaller were the total changes in the colour of beech and oak wood under the influence of ultraviolet radiation. The total changes in the colour of beech densified at temperatures of 100°C and 150°C that took place under the influence of ultraviolet radiation were twice as high as in the case of densified oak wood. The colour of oak wood modified at a temperature of 200°C did not change significantly in 300 h of light irradiation.</p> Agnieszka Laskowska ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/3828 Mon, 02 Sep 2019 00:00:00 -0400