http://revistas.ubiobio.cl/index.php/MCT/issue/feed Maderas. Ciencia y Tecnología 2020-07-01T00:00:00-04:00 Ruben A. Ananias. ananias@ubiobio.cl Open Journal Systems <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> http://revistas.ubiobio.cl/index.php/MCT/article/view/4017 Efficacy of alternative copper-based preservatives in protecting decking from biodegradation 2020-02-24T23:15:57-03:00 Stan T. Lebow stan.lebow@usda.gov Katie M. Ohno stan.lebow@usda.gov Patricia K. Lebow stan.lebow@usda.gov Michael H. West stan.lebow@usda.gov <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> 2020-07-01T00:00:00-04:00 ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/4018 Evaluation of the calorific values of wastes from some tropical wood species 2020-02-24T23:20:37-03:00 Aurel Lunguleasa lunga@unitbv.ro Cosmin Spirchez lunga@unitbv.ro Octavia Zeleniuc lunga@unitbv.ro <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> 2020-07-01T00:00:00-04:00 ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/4019 Alternative model to determine the characteristic strength value of wood in the compression parallel to the grain 2020-02-26T11:07:21-03:00 André Luis Christoforo aquino.vini@hotmail.com Vinicius Borges de Moura Aquino aquino.vini@hotmail.com José Silvio Govone aquino.vini@hotmail.com Alfredo Manuel Pereira Geraldes Dias aquino.vini@hotmail.com Tulio Hallak Panzera aquino.vini@hotmail.com Francisco Antonio Rocco Lahr aquino.vini@hotmail.com <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> 2020-07-01T00:00:00-04:00 ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/4076 Estimation of moisture in wood chips by near infrared spectroscopy 2020-04-01T09:40:19-03:00 Evelize A. Amaral paulo.hein@ufla.br Luana M. Santos paulo.hein@ufla.br Paulo R. G. Hein paulo.hein@ufla.br Emylle V. S. Costa paulo.hein@ufla.br Paulo F. Trugilho paulo.hein@ufla.br <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> 2020-07-01T00:00:00-04:00 ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/4064 Dimensional stability and colour responses of Pinus elliottii wood subjected to furfurylation treatments 2020-03-30T11:20:37-03:00 Andrey Pereira Acosta gattodarci@gmail.com Henrique Römer Schulz gattodarci@gmail.com Kelvin Techera Barbosa gattodarci@gmail.com Gustavo Spiering Zanol gattodarci@gmail.com Ezequiel Gallio gattodarci@gmail.com Rafael de Avila Delucis gattodarci@gmail.com Darci Alberto Gatto gattodarci@gmail.com <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> 2020-07-01T00:00:00-04:00 ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/4083 Lightweight tubular fiberboard: Effect of hole diameters and number on panel properties 2020-04-04T12:25:01-03:00 Javad Khakzad ali.shalbafan@modares.ac.ir Ali Shalbafan ali.shalbafan@modares.ac.ir Saeed Kazemi-Najafi ali.shalbafan@modares.ac.ir <p>Special tubular fiberboard with a density of 550 kg/m<sup>3</sup> was manufactured using the round rods for creation of the holes. Physicomechanical properties of tubular fiberboard (6, 8, 10, 12 (mm)) with various hole diameters and number of hole (0, 1, 2 and 3 in a constant cross section) were evaluated. The surface layers density, especially on top of the holes, considerably elevated with increasing the hole diameter. This did create higher bending properties as well as higher internal bond and surface soundness. The structure of webs between the holes, when the holes’ number increases, were predominant factor influencing the panel properties. Weak and loose web structure were obtained by increasing the holes’ number from 1 to 3 within a constant cross section (50 mm × 16 mm) that was due to the less transferred fiber during pressing in the webs’ sections. A corresponding comparison of panel properties with those in American and European standards presents that the minimum requirements according to most of the standards (ANSI A208/2, EN 14755, EN&nbsp;312/P2 and EN 622-5/P1) were obtained.</p> 2020-07-01T00:00:00-04:00 ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/4065 Chemical variation of five natural extracts by non-polar solvent 2020-03-30T11:29:14-03:00 T.A. Prayitno taprayitno@ugm.ac.id R. Widyorini taprayitno@ugm.ac.id G. Lukmandaru taprayitno@ugm.ac.id <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> 2020-07-01T00:00:00-04:00 ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/4081 Changes in colour and mechanical properties of wood polypropylene composites on natural weathering 2020-04-03T22:27:27-03:00 Jayashri Gunjal shakti32@gmail.com Pankaj Aggarwal shakti32@gmail.com Shakti Chauhan shakti32@gmail.com <p>This comparative study focused on understanding the effect of coupling agent and particle size on weathering behaviour of wood polypropylene composite. Two coupling agents, namely maleic anhydride grafted polypropylene and <em>m</em>-TMI (<em>m</em>-Isopropenyl-a,a- dimethylbenzyl isocyanate) grafted polypropylene were used in preparation of the composites. The composites were exposed to outdoor conditions for one year and changes in surface colour and mechanical properties were measured after 2, 4, 8 and 12 months of natural weathering. During the initial four months of weathering considerable colour change was observed with increase in lightness.&nbsp; Mechanical properties were unaffected largely for the initial four months and thereafter started declining. &nbsp;Overall, tensile strength decreased by about 15 % and flexural strength decreased by about 8 % after one year of weathering. The flexural modulus also decreased by about 10 %. Wood particle size was found to affect the aesthetic and strength of the composites after natural weathering. Coupling agents had a positive impact on mechanical properties however their influence on weathering degradation was not noticeable.</p> 2020-07-01T00:00:00-04:00 ##submission.copyrightStatement## http://revistas.ubiobio.cl/index.php/MCT/article/view/4082 Liquid water absorption in coated norway spruce: Impact of heartwood, sapwood, density and weather exposure 2020-04-03T22:33:41-03:00 Tinh Sjökvist tinh.sjokvist@lnu.se Åsa Blom tinh.sjokvist@lnu.se Sheikh Ali Ahmed tinh.sjokvist@lnu.se <p>Water is one of the most significant factors for the durability of wood. A common solution is to use a coating to protect and maintain low water content. However, little knowledge exists how the underlying wood substrate affects the water sorption of coated wood. Therefore, the liquid water absorption of coated and uncoated Norway spruce heartwood and sapwood with a variety of densities was measured by letting the panels float freely in the water. The effect of one year weathering of the coatings was also included.<br> Coated heartwood and sapwood had no difference in water absorption in opposite to uncoated spruce. The influence of heartwood and sapwood seemed to have limited impact when a coating hindered the presence of free water. Wood density had a positive effect on the absorption of coated wood, i.e. low absorption for low-density samples, in opposite to uncoated samples. Low-density characteristic also contributed to a lower increase of water absorption after weather degradation, for samples with water-borne coatings. Natural weathering enhanced the effect of wood characteristics on coated samples, likely by an increase of coating permeability.</p> 2020-07-01T00:00:00-04:00 ##submission.copyrightStatement##