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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-22(2)1.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/305">Full Text PDF</a></p> <p><img style="width: 30px;" src="http://revistas.ubiobio.cl/public/site/images/visepul/e-book_full1.png" alt=""> e-book version</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> mobile version</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=0718-221X20200050&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) Wed, 01 Jul 2020 00:00:00 -0400 OJS 3.1.0.1 http://blogs.law.harvard.edu/tech/rss 60 Efficacy of alternative copper-based preservatives in protecting decking from biodegradation http://revistas.ubiobio.cl/index.php/MCT/article/view/4017 <p>The above-ground performance of decking treated with two alternative copper-based preservative formulations is being evaluated at a test site near Madison, Wisconsin, USA. Southern pine sapwood lumber specimens (38 mm by 140 mm by 910 mm) were pressure treated with 0,93 %, 1,40 % or 2,34 % (oxide basis) actives concentrations of a boron-copper formulation (BC) composed of 7,2 % copper hydroxide and 92,8 % sodium tetraborate decahydrate. Similar specimens were pressure-treated with 0,66 % or 1,32 % actives concentrations of a copper-zinc formulation (CZDP) composed of 18 % copper (CuO basis), 12 % zinc (ZnO basis), 14 % dimethylcocoamine and 56 % propanoic acid. In both cases untreated specimens and specimens treated with a 1% concentration of chromated copper arsenate Type C (CCA-C) were included for comparison.&nbsp; The specimens were installed on racks approximately 760 mm above the ground and periodically evaluated for extent of fungal decay and surface microbial growth. After 18 years in test specimens treated with the lowest solution concentration of BC (0,93 %) suffered substantial degradation and all but three replicates have failed. Obvious decay has not yet been detected in specimens treated to the highest BC concentration (2,34 %), but decay is suspected in one of these specimens. Decking specimens treated with CZDP exhibited no evidence of decay until year 17 when a fruiting body was observed on one specimen treated with a 0,66 % solution concentration. There has been no evidence of decay in specimens treated with 1,32 % CZDP or in either set of specimens treated with 1 % CCA-C. Both BC and CZDP-treated specimens were at least as effective as 1 % CCA-C in minimizing noticeable surface microbial growth. These decking studies confirm that relatively low copper concentrations can provide substantial protection for decking exposed in a moderate climate, and that the CZDP formulation is potentially more effective than the BC formulation. However, caution is warranted in extrapolating these findings to more severe climates and to construction designs that are more likely to trap moisture.</p> Stan T. Lebow, Katie M. Ohno, Patricia K. Lebow, Michael H. West ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/4017 Wed, 01 Jul 2020 00:00:00 -0400 Evaluation of the calorific values of wastes from some tropical wood species http://revistas.ubiobio.cl/index.php/MCT/article/view/4018 <p>The paper aims to analyze and classified some exotic wood species from tropical Africa, on regard to calorific features, in order to view the ability of their biomass to be a solid, natural and renewable fuel.&nbsp; The calorific values of wood wastes of eight tropical species were determined using an oxygen bomb calorimeter. The tested specimens were conditioned at a moisture content of 10%, 20%, and 50%. The influence of moisture content on calorific value and density, heat release rate and calorific efficiency were also analyzed. The biggest high calorific value and low calorific value were obtained by Guaiac and Rose species (21200-20700 kJ/kg). Acajou had the lowest values of high calorific value and low calorific value (18929 and 18456 kJ/kg, respectively). For higher wood density (Guaiac) the higher calorific density was obtained. The moisture content of specimens had negatively influenced the calorific efficiency and rate of energy release. The ash content was below 4% with highest values for Guaiac (3.6%) and the lowest for Acajou (0.5%). The results showed that the analyzed tropical wood species had a forest calorific capacity with 23-47% higher than of European beech, thus can be considered a good potential as renewable energy resources.</p> Aurel Lunguleasa, Cosmin Spirchez, Octavia Zeleniuc ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/4018 Wed, 01 Jul 2020 00:00:00 -0400 Alternative model to determine the characteristic strength value of wood in the compression parallel to the grain http://revistas.ubiobio.cl/index.php/MCT/article/view/4019 <p>Wood strength values are calculated based on the characteristic value, which corresponds to the 5 % percentile of a given probability distribution model. For a few number of samples (12 samples), the Brazilian standard ABNT NBR (7190) establishes an estimator of the characteristic compressive strength parallel to grain of the wood, which may provide a different result when compared with the characteristic value coming from a suitable probability distribution model. Considering the strength results in the parallel compression to the grain of 45 wood species of the hardwood group, Normal, LogNormal, Weibull and Exponential probability distribution models were used for each specie with the purpose of determining the one with the highest adhesion. Calculated the characteristic values by the best probability model distribution, an analysis of variance (ANOVA) was performed in the estimation of the characteristic value of compressive strength, making it possible to identify the most significant terms of the models as well as the quality of the adjustment obtained on such models. The proposed regression model (R<sup>2</sup> adj= 96,56 %) proved to be equivalent to the empirical model of the Brazilian standard. The model proposed here only depends on the mean and the lowest value obtained from the compressive strength in the parallel direction to the grain.</p> André Luis Christoforo, Vinicius Borges de Moura Aquino, José Silvio Govone, Alfredo Manuel Pereira Geraldes Dias, Tulio Hallak Panzera, Francisco Antonio Rocco Lahr ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/4019 Wed, 01 Jul 2020 00:00:00 -0400 Dimensional stability and colour responses of Pinus elliottii wood subjected to furfurylation treatments http://revistas.ubiobio.cl/index.php/MCT/article/view/4064 <p>Organic substances have been used for different wood treatments, especially impregnation procedures, aiming to improve certain wood properties. The objective of this study was to evaluate dimensional stability and colorimetric features for a mature pine wood (<em>Pinus elliottii</em>) impregnated by vacuum-pressure process with variable concentrations (10 wt%, 25 wt% and 50 wt%) of furfuryl alcohol (using ethyl alcohol as catalyst). The wood samples were characterized for: linear shrinkages, linear swellings, shrinkage anisotropy, swelling anisotropy, as well as colorimetric parameters (following the CIELab method). The impregnation with furfuryl alcohol increased the dimensional stability of the studied pine wood and the treatment with 50 wt% of furfuryl alcohol stood out based on these results. Regarding the colour patterns, there were changes in the final colorimetric appearances of the treated wood samples, which acquired darker and reddish colours when compared to the pristine group. The treatment with 50 wt% furfuryl alcohol again was responsible for the highest colour change and, because of that, may be indicated for solid wood products with high added value.</p> Andrey Pereira Acosta, Henrique Römer Schulz, Kelvin Techera Barbosa, Gustavo Spiering Zanol, Ezequiel Gallio, Rafael de Avila Delucis, Darci Alberto Gatto ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/4064 Wed, 01 Jul 2020 00:00:00 -0400 Chemical variation of five natural extracts by non-polar solvent http://revistas.ubiobio.cl/index.php/MCT/article/view/4065 <p>Chemical compounds of wood preservation from plants vary and are not known specific to the species. Chemical analysis of plants is responsible to ensure active compound in natural extracts wood treatment. There are many sources of natural extracts found in Indonesia that were explored for wood preservatives chemicals. They are bark of acacia and alstonia, leaves of orthosiphon and azardirachta and Dioscorea tubers The present study was aimed at investigating the variation of the chemical constituent of natural extracts material of wood preservative through GC-MS analysis. Five natural extract sources were acacia bark (<em>Acacia spp</em>.), pulai bark (<em>Alstonia scholaris</em>), kumis kucing leaves (<em>Orthosiphon spp</em>.), mimba leaves (<em>Azardirachta indica</em>), and gadung tubers (<em>Dioscorea spp</em>.). Two non-polar solvents, i.e., n-hexane and petroleum ether were used for five natural source extractions following ASTM soxhlet extraction. The research showed that triterpene and fatty acid derivatives were the major compounds present in five natural extracts. They were lupeol; 7,22-Ergostadienone; Lup-20(29)-en-3-one; Lup-20(29)-en-3-ol, acetate, (3.beta.)-; urs-12-en-3-one; ethanol,2,2-diethoxy-; stigmasta-5,22-dien-3-ol, acetate,(3.beta.)-; 5H-3,5a-Epoxynaphth[2,1-c]oxepin, dodecahydro-3,8,8,11a-tetramethyl-; linoleic acid; naphthalene, 1-methyl-. These compounds have been assigned as the possibly responsible to against termites or fungi.</p> T.A. Prayitno, R. Widyorini, G. Lukmandaru ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/4065 Wed, 01 Jul 2020 00:00:00 -0400 Estimation of moisture in wood chips by near infrared spectroscopy http://revistas.ubiobio.cl/index.php/MCT/article/view/4076 <p>In order to assess the moisture content of wood chips on an industrial scale, readily applicable techniques are required. Thus, near infrared (NIR) spectroscopy was used to estimate moisture in wood chips by means of partial least squares regressions. NIR spectra were obtained in spectrometer with an integrating sphere and optical fiber probe, on the longitudinal and transverse surface of <em>Eucalyptus </em>wood chips. The specimens had their masses and NIR spectra measured in 10 steps during drying from saturated to anhydrous condition. Principal Component Analysis was performed to explore the effect of moisture of wood chip on NIR signatures. The values of moisture content of chips were associated with the respective NIR spectra by Partial Least Squares Regression (PLS-R) and Partial Least Squares Discriminant Analysis (PLS-DA) to estimate the moisture content of wood chips and its moisture classes, respectively. Model developed from spectra recorded on the longitudinal face by the integrating sphere method presented statistics slightly better (R²cv = 0,96; RMSEcv = 7,15 %) than model based on optical fiber probe (R²cv = 0,90; RMSEcv = 11,86 %). This study suggests that for calibration of robust predictive model for estimating moisture content in chips the spectra should be recorded on the longitudinal surface of wood using the integrating sphere acquisition method.</p> Evelize A. Amaral, Luana M. Santos, Paulo R. G. Hein, Emylle V. S. Costa, Paulo F. Trugilho ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/4076 Wed, 01 Jul 2020 00:00:00 -0400