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European Journal of Wood and Wood Products
Journal Prestige (SJR): 0.624  Citation Impact (citeScore): 1 Number of Followers: 3  Hybrid journal (It can contain Open Access articles)ISSN (Print) 0018-3768 - ISSN (Online) 1436-736X Published by Springer-Verlag  [2468 journals]
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- Preliminary study of colorimetry as an auxiliary tool for Manilkara spp.
wood discrimination-
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Abstract: Abstract This study aims to collect and calculate colorimetric parameters (CIELab) to group samples using a traditional colour classification chart. It also aims to test the efficiency of visible spectroscopy in the discrimination of wood identified as maçaranduba and maparajuba, from authorized exploitation in a conservation unit in the Brazilian Amazon, as well as to classify those results by a model for the discrimination between genera of the Sapotaceae family. The colour parameters and visible spectra of both RESEX and xylotheque samples were acquired for colour classification, Principal Component Analysis (PCA), and Linear Discriminant Analysis (LDA) to build and validate a model. The RESEX samples were categorized into 3 classes of brown and all subjects had darker and less saturated tones. PCA of the RESEX based on raw and treated data with Savitzky-Golay 1st derivative presented a colour similarity among the samples, generating some groupings of Manilkara as well as dispersion of samples from the same subject. The LDA based on the raw xylotheque data with surface refreshment had an accuracy of 85.33% and classified all the samples as Pouteria. The LDA based on the raw xylotheque samples without surface refreshment had an 81.33% accuracy level and correctly identified most of the RESEX samples as Manilkara, however still presented misidentification as Pouteria and inconclusive/overlapping genus classification. This work corroborates how complex the relationships within the Sapotaceae family are and indicates a preliminary and potential use of VIS spectroscopy as an auxiliary tool for Manilkara spp. wood discrimination.
PubDate: 2023-10-01
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- Surface adhesion of pMDI resin on wood biopolymer model films
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Abstract: Abstract Even though polymeric diphenylmethane diisocyanate (pMDI) resin shows strong adhesion in wood bonding, its adhesion to major wood biopolymers is not fully understood. Thus, this study reports the surface adhesion of pMDI resin on wood biopolymer model films, such as cellulose, hemicellulose and lignin. The effects of wood biopolymer chemical structure, surface roughness, and wettability on the adhesion measurement were examined. The results revealed that, in general, pMDI exhibited greater adhesive force toward lignin model films compared with other biopolymer films. This is because lignin has abundant phenolic hydroxyl groups and aromatic rings, smoother surface, and higher surface-free energy than celluloses and hemicelluloses. This result suggests that the surface properties and hydroxyl group content of wood biopolymer provide a significant role in the bonding interaction between pMDI resin and wood biopolymers.
PubDate: 2023-10-01
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- Organic–inorganic hybrid of silica sol to promote flame retardant and
mechanical properties of wood-
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Abstract: Abstract As a potential building material, fast-growing wood (such as poplar) is prone to easy combustion and having poor mechanical properties, which limit its application range. In order to improve the reinforcing effect of SiO2 on poplar wood, we propose a method of immersing silica sol into wood smoothly. In this method, the sol and a non-ionic surfactant are first treated via organic–inorganic hybridization. This surfactant has a strong penetration effect, and the sol is introduced into the wood through hybridization. By impregnating the wood, the flexural strength and flexural modulus of elasticity increased by 79.7% and 89.5%, and the compressive strength along the grain increased by 105.1%. The treated wood also showed flame retardation, reducing the heat release rate (HRR), carbon dioxide yield (CO2Y), total heat release (THR), specific extinction area (SEA) and total smoke release (TSR), with delaying ignition and burn-through time. This method incorporates silica sol in wood via physical filling and chemical bonding, thereby improving the mechanical and flame retardation properties of wood as an outdoor building material.
PubDate: 2023-10-01
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- Effects of surface perforation on the drying characteristics and sound
absorption coefficients of Russian poplar board-
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Abstract: Abstract This study investigated the effects of surface perforation on the drying characteristics and sound absorption coefficients of Russian Simon poplar lumber. The drying process and moisture content (MC) were monitored. The results showed that the perforated wood samples reached 10.9% MC after 14 days, while the control samples reached 11.7% MC after 16 days. The difference in MC between the core and shell of the perforated and control specimens was 1.29% and 2.71%, respectively. The drying stress of perforated wood lumber was tension stress, while compressive stress was observed in control samples. The sound absorption coefficient (SAC) was measured using the transfer function method and two microphone impedance tubes. The results showed that the perforated samples had improved in SAC compared to the control samples, particularly at 1000 Hz. The average SAC of the perforated samples at 1000 Hz was 41% higher than that of the control samples. Furthermore, the noise reduction coefficient (NRC) exhibited a 69% improvement in the perforated samples. Statistical t-test analyses confirmed the significant difference in the SAC of the perforated pieces. Further experiments revealed that the sound absorption performance of perforated samples could be significantly improved by adding air gaps in the back cavity (1, 2, 3 cm), particularly at low frequencies. These findings suggest that perforated poplar boards could be useful for wall building applications when combined with air gaps in the back cavity to enhance sound absorption performance.
PubDate: 2023-10-01
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- Dewatering fresh bamboo strips using supercritical carbon dioxide
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Abstract: Abstract Rapid drying of bamboo with good quality is a key challenge. Supercritical CO2 (ScCO2) dewatering of green wood is fast and creates timber with unique properties due to the removal of water directly from cell lumens as a result of cycling between supercritical and gas phases. To investigate the effect of ScCO2 on dewatering rate (DR), water transfers and quality of bamboo, fresh moso bamboo (Phyllostachys edulis) strips were dewatered at temperature of 40 and 55 °C, and pressure of 10, 20 and 30 MPa. The results showed that bamboo strips were fast dewatered by ScCO2 with the DR between 23.8%/h and 63.7%/h. The DR decreased with an increase in sample length. The DR of the 5 mm samples increased with temperature and pressure, whereas a contrary trend was observed for the 30 and 150 mm samples. After dewatering, the moisture content was uniform along the tangential direction of bamboo, but significant moisture gradients were observed along the radial direction, in particular, towards bamboo inner face. Most moisture in bamboo was transferred along the longitudinal direction, while a small amount of water was also removed in the transversal direction, especially along the radial direction toward bamboo inner face. No shrinkage and cracks were observed in the bamboo strips after ScCO2 dewatering. ScCO2 dewatering offers a fast and quality solution for bamboo water removal.
PubDate: 2023-10-01
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- Effect of fiber separation degree on the properties of bamboo fiber
composites-
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Abstract: Abstract The steam explosion is an economical and effective method for obtaining bamboo fibers (BFs). However, little attention has been paid to the differences in the separation forms of steam-exploded fibers, which may affect their application in the field of composites. In this study, the steam-exploded fibers were classified into five categories (BF-1 to BF-5) according to their degree of separation (from low to high). The effects of different bamboo fibers on the structure and properties of bamboo fiber composites (BFCs) were investigated using scanning electron microscopy, physical properties testing, flexural testing, internal bonding testing, and dynamic mechanical analysis. The results indicated that the fibers separated from bundles into single fibers with progressively smaller diameters as the degree of separation increased. Higher degrees of fiber separation produced composites that had better water resistance performances. The water absorption of composites made with BF-5 was 15.02% lower than that of composites made with BF-2. An excessively low or high separation degree negatively affected the mechanical properties and interfacial bonding properties of the BFC. Composites made with BF-4 had the highest flexural properties and fiber/matrix interfacial bonding, with a flexural strength, flexural modulus, and energy storage modulus that reached 102 MPa, 6970 MPa, and 5412 MPa, respectively. Fiber separation degree is a key factor influencing the properties of composites. When preparing composites with enhanced performance using the steam explosion method, fibers with a moderate degree of separation should be prioritized.
PubDate: 2023-10-01
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- Creping technology and its factors for tissue paper production: a review
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Abstract: Abstract Tissue products such as facial tissue and paper towels have been playing a crucial role in promoting hygiene and maintaining good health, since they are commonly available and widely used nowadays. The production of low-density tissue paper typically involves a key creping process that contains pressing and adhering the wet web onto a high-speed Yankee cylinder, followed by releasing the creped sheet with a stationary creping blade to form periodic micro-folds within the tissue structure. This paper discusses and reviews the mechanisms of tissue creping technology, as well as the factors that impact the creping process and tissue properties. These factors primarily include the dryness of the tissue web, creping rate, properties of the pulp raw material, Yankee coating, crepe doctor blade, and tissue drying machines. It is indicated that the creping process, as a multifaceted and integrated treatment for tissue production, can be significantly enhanced through the concerted efforts of the aforementioned factors to achieve greater creping efficiency. However, further endeavors are necessary to address the constraints stemming from the pilot experimental equipment and data, as well as modeling simulation, to enable a more comprehensive examination of the creping process and its mechanism. This review offers a practical overview and comprehensive understanding of the creping technology and its underlying factors for tissue production.
PubDate: 2023-10-01
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- Extractives in Douglas firs (Pseudotsuga menziesii (Mirb.) Franco) from
three sites in south-west Germany and potential opportunities for
valorization-
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Abstract: Abstract Owing to favorable wood properties and its resilience to the effects of climate change, Douglas fir (Pseudotsuga menziesii) is a promising tree species in Central Europe. Its wood and bark extractives could also serve as feedstock for the production of bio-based materials and platform chemicals. In this study, sapwood, heartwood, knotwood and bark extractives of Douglas firs originating from three differently aged stands in south-west Germany were investigated. Two different extraction methods with organic solvents were compared: a mixture of cyclohexane/ethanol and a successive method using petroleum ether, acetone and methanol. Extraction yields obtained with the successive method were higher, however one-step extraction was very efficient considering the number of samples that could be extracted and is therefore useful for a fast screening. At all sites, extract yields from sapwood, heartwood and bark were highest close to the tree top, while at the two older sites, an additional maximum was found at 1.3 m height. Knotwood extractives tended to decline with increasing tree height. The most abundant substance with economic importance was taxifolin, yielding up to 13% of dry weight in bark, whereas knotwood contained high amounts of resin acids and the lignan nortrachelogenin. Contrary to other studies, the present study found no evidence of a significant site effect on yield and composition of extracts. Overall, many different compounds for future bio-economic applications were found so that the preferential utilization of extractive-rich bark and crown material could foster an integral valorization of trees, supplementing with existing high grade timber production.
PubDate: 2023-10-01
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- Phosphorylation as a means to reduce energy consumption for fibrillation
when producing micro- and nanofibrillated cellulose from unbleached
Eucalyptus sp. pulps-
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Abstract: Abstract Lignocellulosic biomass-derived micro- and nanofibrillated cellulose (MNFC) is a promising material for the production of a wide variety of products, but the high energy consumption of mechanical fibrillation limits the material’s industrial potential. This study aimed to investigate the use of monoammonium phosphate ((NH4)H2PO4) and urea (CH4N2O) for the pretreatment of unbleached Eucalyptus sp. kraft pulp as a strategy to reduce energy consumption during mechanical fibrillation. Pretreatments were carried out using two reagent molar mass ratios, namely 1:1:1 (1.0 g of fiber/1.2 g of (NH4)H2PO4/4.9 g of CH4N2O) and 1:2:2 (1.0 g of fiber/2.5 g of (NH4)H2PO4/10.0 g of CH4N2O). Pretreated samples were then oven-heated at 150 °C for 20, 40, or 60 min to promote phosphorylation reactions. MNFC was obtained by mechanical shearing using a Super Masscolloider mill. The resulting samples were analyzed for morphology, turbidity, water stability, Fourier transform infrared spectra, X-ray diffraction patterns, and energy consumption. The derived films were evaluated for mechanical properties. Pretreatments carried out using reagent ratios of 1:1:1 and 1:2:2 and heat-treated for 60 min formed individualized microstructures. These pretreatments reduced energy consumption during fibrillation by 69% and 73%, respectively. Heat treatment time for activation of chemical reactions has a stronger influence on phosphorylation efficiency than reagent ratio. The use of different reagent ratios (1:1:1 and 1:2:2) combined with a heat treatment time of 60 min provided similar results. These conditions were the most effective in facilitating mechanical fibrillation.
PubDate: 2023-10-01
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- Effect of bamboo nodes on crack generation of round bamboo and
bamboo-based composites during drying-
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Abstract: Abstract Cracking of bamboo results in structural failure, safety issues, resources waste, and economy loss. The influence of nodes on the cracking behavior of bamboo still remains unclear. In this study, cracks in bamboo were classified into three types (end cracking, node cracking, and internode cracking), and the node cracking mechanism was clarified. The results revealed that 72%, 77%, and 89% of the cracks in the middle portion of the samples were generated at the node positions for the round bamboo, laminated bamboo lumber, and flattened bamboo board, respectively, indicating that much more cracks were generated in the nodes than in the internodes during drying process. The reason was the greater tangential shrinkage of bamboo nodes. The thickening and deflection of vascular bundles in nodes caused a higher fiber content and substance density, and thus resulted in greater shrinkage. This study confirmed that bamboo node played a dominant role in the crack generation in both bamboo and bamboo-based composites. The results in this study provided fundamental information for understanding the cracking behavior of bamboo and developing anti-cracking techniques for bamboo.
PubDate: 2023-10-01
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- Effect of variable engineered micro-geometry of the cutting edges of
circular saws on the surface quality of SPF boards-
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Abstract: Abstract The wood processing industry seeks to reduce maintenance and production costs while increasing productivity and revenues accordingly. Improving the surface quality of wood in the first phase of transformation helps to maximize the use of wood fibers. Variable engineered micro-geometry was applied to teeth of guided circular saws used in a bull-edger system, and its effect on the surface quality of SPF (spruce-jack pine-balsam fir) boards was assessed. Trials were carried out on a test bench with two types of saw blades: saws with up-sharp tips without edge modification, and saws with modified cutting edges based on a waterfall profile. Cants were fed at the rate of 145 m/min for a cutting speed of 2600 rpm resulting in a nominal feed per tooth of 1.33 mm. Saws with three levels of wear (after 0, 255, and 900 min of working at a sawmill) processed the cants under frozen and unfrozen wood conditions. A total of 336 board samples were produced. Surface quality of boards was assessed using standard parameters of roughness and waviness. The results revealed that the saw with modified waterfall edge profile showed better performance in terms of wood surface finish and wear rate due to the variable engineered micro-geometry. Frozen cants had a better surface finish. Roughness and waviness parameters were sensitive to changes in wear of tips.
PubDate: 2023-10-01
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- Knot extractives responsible for the yellowing of white-coated pine wood
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Abstract: Abstract Opaque water-based coatings are prone to show discoloration when they are applied on knotted pine wood. This is seen as a yellow–brown spot, caused by the high concentration of specific wood extractives in the knots. Temperature and relative humidity cause the migration of these extractives through the coating while UV radiation may cause the discoloration of some of them. This work studied some of the extractives found in knots of Pinus cembra. Knotwood samples were subjected to Soxhlet extraction with hexane, ethanol, and acetone:water (95:5 v/v) and analyzed by high-pressure liquid chromatography and mass spectroscopy. Wood boards of P. cembra were painted with a commercial white water-based coating and subjected to accelerated ageing. The yellowed coating was scraped off and analyzed by infrared spectroscopy and high-pressure liquid chromatography and mass spectroscopy. Two stilbenes, five lignans and two flavonoids were detected in the polar knot extracts and their presence was confirmed in the discolored coating over the knots.
PubDate: 2023-10-01
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- Size effects on the bending strength of Chinese larch pine laminated
veneer lumber-
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Abstract: Abstract Owing to the excellent strength-to-weight ratios, Laminated Veneer Lumber (LVL) becomes one of the favorable building materials for timber structures, especially for long-span structural beams. Attempts have been made to use high-yielding Chinese larch pine as a raw material of structural LVL, which could expand the raw material source for engineering constructions. Understanding the bending properties of Chinese larch pine LVL (CLP-LVL) is critical for promoting the development of CLP-LVL for structural applications. In this study, flatwise and edgewise bending strengths of CLP-LVL under different specimen sizes were experimentally investigated. Results showed that the CLP-LVL could provide comparable or even superior bending properties for structural applications. Subsequently, the size effects on the bending strengths of CLP-LVL were evaluated. It is suggested that the depth and width effects under a constant span-depth ratio on the bending strength should be considered when adopting strength theories to predict the bending strength of CLP-LVL. Correlations for calculating the depth and width adjustment factors related to specimen size were proposed. Results showed that the bending strengths of CLP-LVL specimens could be well predicted by the reference bending strength and proposed depth and width adjustment factors. Besides, the depth and width effect factors of flatwise bending strength for CLP-LVL determined by the slope method were 0.14 and 0.12, while that of edgewise bending strength were 0.09 and 0.05, respectively. Especially, the proposed size effect factors for CLP-LVL were further verified by the experimental results of structural-size CLP-LVL specimens.
PubDate: 2023-10-01
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- Prediction of the color change of surface thermally treated wood by
artificial neural network-
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Abstract: Abstract Surface thermal treatment (STT) can achieve efficient and successful thermal modification on wood surfaces, resulting in a beautiful, natural, uniform darker color and velvety texture. This study aimed to evaluate the effect of STT on White Ash, Yellow Poplar, and Red Oak specimens using a heated press at varying temperatures and times. To enhance the material utilization, reduce the number of experiments, and optimize the process, we employed artificial neural network (ANN) to model the relationship between the provided color, treatment time, and temperature required to attain the desired color. As the ANN model can simulate the process result very fast with a high degree of accuracy ( \(R^2\) above 0.96), it allowed us to rule off approximately 95% of the possible combinations, conducting a minimal subset of experiments and thereby saving an enormous amount of time (one experiment takes five hours to be prepared appropriately and more than 20 samples need be tested to get the ideal color). Previous research either investigated how to use ANN or demonstrated other new methodologies for applying thermal treatments. In this study, we propose a novel method to do efficient thermal treatment and train an ANN model which helps eliminate the misdeem experiments. Our ANN model can successfully predict the color change of thermally treated wood. The mean absolute percentage errors (MAPE) from our models were from 10.61 to 10.97% for training and 10.00–10.41% for testing. All obtained determination coefficients ( \(R^2\) ) were above 0.96. We have demonstrated our method on White Ash, Yellow Poplar, and Red Oak specimens, compared the findings to previous baselines, and exhibited an improvement of over 30% for \(R^2\) in several instances.
PubDate: 2023-10-01
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- Porous silicon modified wood as a high-efficiency solar steam generator
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Abstract: Abstract In recent years, solar water evaporation system by utilizing wood-based photothermal material has drawn a lot of attention and displayed promising practical application prospect. However, challenges still remain in terms of its relatively low efficiency. Here, a facile, cost-efficient, and scalable method was proposed to prepare porous silicon loaded wood (porous silicon/wood) as solar steam generation device for seawater desalination. The porous silicon, which was obtained from in situ acid etching of Al-Si alloy powder, could be firmly deposited on the wood surface via capillary infiltration method. It provides an excellent light-absorber layer to enhance its light absorption properties, which is beneficial for broad solar absorption. Meanwhile, the hierarchical porous structure based on natural balsa wood contributes to vapor escape. The evaporation rate of porous silicon/wood reaches 1.57 kg m−2 h−1 under 1 sun illumination with 95.8% solar conversion efficiency. In addition, the simulated seawater desalination test results show that the concentration of various ions in seawater decreases significantly by using porous silicon/wood as solar-thermal material, which meets the WHO water quality standard. In addition, porous silicon/wood shows decent salt-tolerance for high-salinity brine desalination. This study provides a simple method to manufacture high-efficiency solar steam generator, which has potential for future large-scale applications. On the other hand, capillary infiltration method gives an effective strategy for wood asymmetrical modification.
PubDate: 2023-10-01
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- Effects of different pretreatment methods on the dimensional stability of
steamed bamboo units-
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Abstract: Abstract To optimize steam pretreatment conditions and solve the problem of bamboo deformation more effectively under standard atmospheric pressure, the dimensional stability of bamboo units was used as the main evaluation index to compare acid, alkali, and ultrasound combined steam heat pretreatments in this paper. An optimized process of zinc chloride pretreatment, 40% initial moisture content, and 140 °C (0.1013 MPa) by orthogonal experimental analysis was proposed. Under the optimized condition, the moisture excluding efficiency (MEE) of treated bamboo could reach 31.14% and the anti-swelling efficiency (ASE) could reach more than 37.10%. Moreover, the samples were characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and colorimeter. The results showed that the relative crystallinity of bamboo increased by 1.82%, the hydroxyl percentage (HP) decreased by 1.99%, and the total color change (∆E*ab) increased by 21.19 − 25.09. The treated surface became rougher, and cracks appeared in some weaker areas, accelerating starch loss and removing granular attachments around the pits. This work provides an effective pretreatment for improving the dimensional stability of steamed bamboo units.
PubDate: 2023-10-01
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- Profiling of oxidative enzymes and structural characterization of
biologically pretreated oil palm wood chips-
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Abstract: Abstract Globally, biological pretreatment has become a new interest among researchers as a substitute pretreatment for a cleaner and greener technology approach to the waste management program. The study comprehensively examined the chemical changes in oil palm lignocellulosic materials pretreated with three species of wood degraders, namely, Lentinus tigrinus strain FBJG3, Clitopilus prunulus strain ST3, and Trametes lactinea strain FBW. The findings were used to limit potential wood degrader (s) for the secretion of oxidative enzymes, i.e., laccase, manganese peroxidase and lignin peroxidase, using principal component analysis (PCA). Among them, L. tigrinus and T. lactinea were selected as potential candidates, with a significant amount of laccase enzyme produced with 8.8-fold and 1.2-fold increase towards the end of biological pretreatment period (Day 120). Syringyl (S) to guaiacyl (G) ratio decreased as the degradation progressed in the wood chips pretreated with L. tigrinus, suggesting that this strain preferentially attacked the S-lignin units. Conversely, the increase in the S/G ratio in wood chips pretreated with T. lactinea was observed, suggesting that this strain preferably attacked the G-lignin units. This study provides a new overview of chemical changes during biological pretreatment of oil palm lignocellulosic materials. These findings could be used to selectively pretreat lignocellulosic materials during replanting of oil palm. As in the case of conventional replanting, the diseased palms are left for natural degradation.
PubDate: 2023-10-01
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- Industrial assays to evaluate the efficacy of vacuum pressure impregnation
with commercial wood preservatives to eliminate the pinewood nematode,
Bursaphelenchus xylophilus, and other nematodes from Pinus pinaster wood-
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Abstract: Abstract To demonstrate the efficacy of the vacuum pressure impregnation (VPI) with commercial wood preservative products to eliminate the quarantine organism, pinewood nematode (PWN), Bursaphelenchus xylophilus, and other nematodes from maritime pine (Pinus pinaster) wood, in vitro assays and industrial assays in horizontal industrial autoclave tanks were conducted. In vitro nematicidal activity assays through direct exposure of the PWN 3rd-stage dispersal juveniles, the resistance juvenile stage, extracted from naturally infected P. pinaster revealed 100% nematode mortality with three commercial wood preservatives. Nematode mortality was also assessed in VPI industrial assays with the three commercial wood preservatives using naturally PWN infected P. pinaster experimental units, with various diameters and sizes. After VPI treatment, the nematode mortality ranged from 99.9761 to 100%. After incubation, the mortality of the total number of nematodes increased and, in all sections, the nematode mortality was higher than 99.9981% and in some it was 100% indicating that wood impregnated with preservative products does not constitute an environment favorable to the reproduction and development of nematodes. Overall, our findings demonstrated that the efficiency of the VPI process results from the joint action of the physical effect of pressure and vacuum and of the nematicidal effect of the preservative product. VPI treatment can be considered a valuable approach to eliminate PWN and other nematodes from maritime pine wood avoiding the subsequent application of the heat treatment.
PubDate: 2023-10-01
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- Analysis of stress development during kiln drying of beech timber
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Abstract: Before use, timber must have reduced moisture content. Kiln drying causes cracking risk. This study aims to evaluate the risk of cracking during the drying of beech wood samples using the response surface methodology. Additionally, we aim to develop an empirical model that describes critical tensile stress during the early drying stages and the air parameters commonly used in kiln-drying schedules for beech timber, specifically, the effects of dry-bulb temperature (DBT) and wet-bulb depression (WBD). Nine options of drying conditions were analyzed in the study according to the Central Composite Design assumptions; they were combinations of three options of DBT (30, 40, and 50 °C) and three options of WBD (4, 5, and 6 °C). During the experiments, tangential shrinkage of the wood samples was completely restrained with a load cell that measured generated tensile drying stresses. The results of the ANOVA analysis confirmed that the DBT is the only factor significantly influencing the tensile stress at failure (σf). The second-order effect between DBT and WBD has also been confirmed. The drying condition causing the highest risk of cracking was shown using the multiple contour plots of tensile stresses and the moisture content at failure (MCf). Reliability theory was used to predict the cracking risk of wood tissue. The analysis confirmed the dependence of the cracking risk of wood tissue on drying conditions. When DBT is equal to 30 °C, the cracking risk increases as the air relative humidity (RH) decreases. However, during the drying of beech wood samples at a temperature of 50 °C, decreasing the RH in a range corresponding to the increase of WBD from 4 to 6 °C reduces the cracking risk, which is indicated by the lower moisture content at failure (MCf) of the wood samples. Graphical
PubDate: 2023-10-01
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- The mechanical properties deterioration of rubberwood-latex sludge flour
reinforced polypropylene composites after immersing in different water
conditions-
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Abstract: Abstract The hydrophilic nature of wood-plastic composites (WPCs) is a disadvantage that impacts its performance in applications for construction and building products. Therefore, developing the WPCs into composites that reduce water absorption needs further evaluation. The current work investigates the effects of different water types (distilled water, and water from the Gulf of Thailand and the Andaman Sea), latex sludge types, and immersion time on the physical and mechanical properties of rubberwood-latex sludge flour-reinforced polypropylene composites. The composite samples were produced by a twin-screw extruder (mixing) and a compression molding machine (forming). The results revealed that the composites exposed to different water conditions for a long period resulted in significant (α = 0.05) reduction in the modulus of rupture, modulus of elasticity, screw withdraw strength, and hardness with maximum percentage reduction values of 79.9, 117.5, 69.9, and 5.84, respectively. However, adding the latex sludge at 25 wt% resisted deterioration. The composites immersed in Andaman Sea water exhibited the least water absorption and deterioration for all the mechanical properties with a minimum hardness loss (3.74%). The composites immersed in distilled water showed the maximum deterioration for all mechanical properties, with 117.5% loss in modulus of elasticity. Overall, adding the latex sludge flour to the composites made them resistant to mechanical properties deterioration, which is favorable for WPCs used in environments involving contact with the seawater, especially the Andaman Sea.
PubDate: 2023-10-01
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