Based on the aging characteristics of wooden components, this study adopted artificial accelerated aging and fire propagation apparatus (FPA) to examine how aging affects the combustion behaviour, fire risk, and smoke-heat hazards of pine wood commonly used in ancient structures. Wood specimens with dimensions (100 & times;100 & times;10 mm and 300 & times;100 & times;10 mm) matching fire performance tests were prepared, and artificial accelerated photoaging treatment was conducted to obtain aged samples with 0, 60 and 120 aging cycles in accordance with the accelerated aging test protocol for wood materials. The results indicate that pine combustion involves three distinct thermal stages: pyrolysis, smouldering, and flaming, with critical high-risk transition points identified. Aging intensified fire risk and related hazards across all stages, particularly accelerating flame spread on vertical components.
Employing rapid surface loading (160 degrees C, 10 s) during hot pressing can elevate the peak density of the wood's surface, thus augmenting its rigidity and impact resistance capabilities. Subsequently treatment with superheated steam (190 degrees C, 1.5 h). The findings of the study indicate that the impact resistance of the modified rubberwood increased by 29.2% compared to the untreated control samples. Remarkably, it even surpassed that of Fraxinus mandshurica, a premium quality hard wood species. Moreover, the wood's colour has transformed into a purple brown hue, endowing it with a more aesthetically pleasing and refined appearance. Additionally, the paint film on the wood's surface exhibits strong adhesion, meeting the requirements of Grade 1 as stipulated by the national standard. This combined modification method effectively enhances the overall performance of rubberwood.
Since heartwood parts generally contain higher levels of extractive, in this study, several extraction methods were carried out as a pre-treatment of Acacia mangium and Acacia aulacocarpa heartwood sawdust, followed by kraft pulping in a micro digester. After extraction, pulp properties from the two species were significantly different. Polar solvent extraction effectively increased pulp yield and decreased kappa number levels, while the successive extraction had less impact. Pulp kappa number significantly increased after n-hexane extraction. Compared to the control samples, pulp brightness of A. aulacocarpa wood for single solvent and successive extraction increased sharply. The overall pulp hexuronic acid content significantly decreased after extraction. Successive extraction led to significantly lower pulp viscosity compared to a single solvent extraction. In general, heartwood extraction significantly increased the pH values of A. aulacocarpa black liquor. Considering pulp properties, this study recommends hot-water extraction for A. mangium and successive extraction (n-hexane and methanol) for A. aulacocarpa.
This study evaluates the environmental impact of producing wood plastic composites (WPC) using recycled polyethylene (rPE) compared to virgin polyethylene (PE). The assessment was based on a Life Cycle Assessment (LCA) framework in accordance with ISO 14040 and ISO 14044 standards, applying the Leontief model to quantify environmental performance indicators. Two key parameters were analysed: specific CO2 emissions and the amount of waste destined for landfilling. The findings indicate that the incorporation of rPE into WPC production leads to an approximate 2.7-fold reduction in total CO2 emissions and a tenfold decrease in landfilled waste. Even when accounting for the additional 10% emissions associated with waste collection and sorting, the overall reduction remains above 60%. These findings are consistent with contemporary circular economy strategies and confirm the environmental feasibility of substituting virgin polymers with recycled feedstock.
This study investigates the impact of top soundboard thickness on the modal parameters of violins. By analysing variations in plate thickness, the research explores how these changes influence modal frequencies, damping characteristics, and overall acoustic properties. Findings indicate that increased thickness results in lower modal frequencies and better damping, which may affect sound quality. The study references established research on violin acoustics and discusses the structural implications of varying plate thicknesses, particularly concerning the effects of string tension. These insights contribute to a deeper understanding of violin construction and offer potential guidelines for optimising instrument design to achieve desired tonal qualities.
This study investigates the tensile shear strength of maple plywood bond lines bonded with quebracho tannin adhesive, modified using different hardeners: hexamine, paraformaldehyde, and methylene diphenyl diisocyanate. Adhesives were prepared by dispersing tannin powder in water, followed by the incorporation of each hardener, and applied to three-layer veneer panels cured under hot pressing. Bond line performance was evaluated under dry and wet conditions using tensile shear tests, with wet testing incorporating an accelerated cyclic-boil aging protocol. The results revealed that paraformaldehyde-modified tannin adhesives achieved the highest dry strength, 3.5 MPa, significantly exceeding the performance of both other tannin-based systems and synthetic adhesives. In contrast, under wet conditions, no significant differences were observed among tannin-based and synthetic adhesives, underscoring the strong influence of moisture on performance.
In this study, the effects of a chemical-mechanical modification system on low-density poplar (Populus tremula L.) wood were investigated without external confinement. Wood samples were initially treated with an alkali-sulphite solution (2.5 M NaOH, 0.4 M Na2SO3 for 7 h) to induce partial delignification, after which they were densified at 100 degrees C under 5 MPa pressure. Following this process, a significant increase in density to 1.22 g/cm(3) (+172.6%) was recorded. Mechanical evaluations indicated substantial enhancements; specifically, Brinell hardness, bending strength (MOR), and modulus of elasticity (MOE) were improved by 346.3%, 67.4%, and 78.3%, respectively, confirming the successful consolidation of the cellulose network. However, a trade-off was revealed by microscopic analysis, and two distinct failure mechanisms were identified. First, large cracks (similar to 150 mu m) were formed in the core due to diffusion limitations that prevented full chemical penetration. Second, widespread micro-cracks (similar to 4 mu m) were triggered in the densified shell by the Poisson effect due to the lack of lateral confinement. These results suggest that while hardness is significantly improved by unconstrained densification, compressive performance is compromised by the resulting defects. While the modification was intentionally applied to 35 mm thick lumber to reveal diffusion limitations and Poisson-induced defects under unconstrained conditions, small, defect-free specimens were subsequently selected for mechanical testing to isolate and characterize the intrinsic properties of the successfully modified regions near the surface.
Using silver-loaded nano-TiO2 (Ag-TiO2) and ethylene-vinyl acetate (EVA) emulsion as raw materials, a core-shell structured Ag-TiO2@EVA composite material was synthesized to impart antimicrobial, mold-proof, and decay-resistant properties to wood. The study investigated the composite material's efficacy in controlling wood-staining fungi and molds, as well as its decay resistance and antifungal performance. The results showed that when the film thickness was between 0.12 to 0.15 mm with an Ag-TiO2 content of 20% or more, or when the film thickness was between 0.21 to 0.24 mm with an Ag-TiO(2 )content of 15% or more, the control efficacy against Botryodiplodia theobromae and Aspergillus niger reached 100%, and the decay resistance grade against Poria placenta was level I. For samples with 10% Ag-TiO2 content, the inhibition zone diameters against A. niger and B. theobromae were both greater than 10 mm, while samples with 15% and 20% Ag-TiO2 content exhibited inhibition zones larger than 20 mm, indicating strong antimicrobial effects.
A series of grey poplar (Populus x canescens) samples was irradiated by strong ultraviolet (UV) light emitter mercury lamp, while another series of specimens were treated with the combination of UV irradiation and water leaching. The total duration of UV irradiation for both series of specimens was 20 days. The colour parameters (CIE L*, a*, b*) were measured and evaluated after both UV irradiation and water leaching. Due to the 20 days of UV irradiation, the initial redness value of sapwood increased 2.69 times, while leaching reduced this factor to 1.77. In case of heartwood, the initial redness value increased 1.34-fold due to the 20-day UV exposure, while the leaching reduced this factor to 1.14. These multiplier values are 2.07 and 1.44 for the yellowness of sapwood, as well as 1.57 and 1.29 for the yellowness of heartwood. The leaching partly removed the yellow and red chromophore molecules generated by the UV irradiation. The samples were slightly lighter after water leaching.
In this study, seven xylophagous fungi (Trametes; Trichoderma A1; Trichoderma A2; Aspergillus; Paecilomyces; Coniochaeta; Gloeophyllum) were exposed to wood preserved with CCA salts, boric acid, and a polyphenolic extract (ExPol). The results showed a prevalence of xylophagous fungi that affects the use of wood. Changes in physical parameters such as mass are accompanied by changes in mechanical properties; variation in weight losses went from 12.69-20.42 %, 6.13-19.70 % and 6.38-23.68% for CCA, H3BO3 and ExPol respectively. In conclusion, variations in response to the preservatives were shown for each microorganism due the fact that metabolism is not the same because they use the substrate components or polymers in different ways for growth, being Expol the best option to inhibit Trametes, Trichoderma A2 and Aspergillus, there's not much difference between CCA and H3BO3 for the control of the rest of the organisms but both are better alternative than ExPol to inhibit their growth.
The extractive analysis of D. verrucosus and A. cunninghamii identified key chemical markers in their resins. GC-MS analysis showed that sesquiterpenes, such as (3-spathulenol and (3-elemene were dominant in the neutral fractions of the two species. Furthermore, diterpenes, especially thunbergol, were found to be dominant in D. verrucosus while absent in A. cunninghamii. In addition, the acidic fractions were primarily composed of fatty and resin acids, mainly palmitic acid (D. verrucosus) and sandaracopimaric acid (A. cunninghamii). The study concludes that the specific combination of sesquiterpenes, fatty acids, and resin acids serves as a chemical fingerprint for the two species.
This study examines the radial variability of apparent wood density in two tropical commercial species, Swietenia macrophylla (mahogany) and Cedrela odorata (cedar), in the Peruvian Amazon. The hypothesis states that both species will present different radial variation patterns in wood density, with C. odorata showing greater heterogeneity due to its older age and the presence of mineral inclusions. Advanced methods, including X-ray microdensitometry and visual analysis with QGIS, were used to obtain radial density profiles. Results showed that C. odorata exhibited higher variability and a wider density range than S. macrophylla, mainly attributed to age and mineral inclusions affecting density measurements. These differences are important for the timber industry, influencing mechanical properties and material selection. The findings emphasize the significance of density variability for sustainable management and improving timber quality in the Amazon region.
This study investigated the effects of moisture content (0%, 12%, 20%, 30%, 40%, 50%) on the mechanical behaviour and damage evolution of Pinus sylvestris var. mongolica three-point bending tests. A Weibull distribution model quantified damage progression, extracting scale (lambda) and shape (k) parameters. Results revealed moisture regulated failure mechanisms, Low moisture (<= 20%) induced brittle fracture (high k, low lambda) with tensile crack dominance and stress concentration. High moisture (>= 30%) promoted ductility (low k, high lambda) via enhanced lambda, driven by shear cracks. Mixed cracks persisted across all stages. Moisture altered cell wall plasticization, inter-fibre friction, and interfacial bonding, modulating damage evolution. Weibull modelling effectively captured stage dependent damage variable trends. Increased moisture facilitated fibre slippage and interlayer shear through lubrication and cell wall softening.This work establishes quantitative links between moisture content, mechanical response, and micromechanical damage mechanisms in wood, providing insights for moisture dependent structural applications of engineered timber.
The high density and large amount of extractives of eucalyptus (Eucalyptus maculata) wood are very unfavorable for the production of its finger-jointed timber. This study examined the mechanical properties of finger-joint nodes during the pressing and unloading processes at the ends, and investigated the effects of chemical agents and heat treatment methods on the performance of finger-joint connections.The results indicated that high end-pressure was crucial for maintaining the stability of finger joints, as a reduction in pressure led to significant displacement relaxation and springback. The high extractive content in eucalyptus had different effects on the bonding performance of different adhesives: polyvinyl acetate (PVAc) adhesive exhibited superior bonding performance, with tensile strength and flexural strength reaching 12.21 MPa and 52.61 MPa, respectively.Furthermore,heat treatment and anhydrous ethanol pretreatment can effectively reduce the impact of extractives at the joint interface, thereby enhancing the bonding strength.Compared to untreated controls, heat treatment improved tensile and flexural strength by 5.7% and 0.6%, respectively, while anhydrous ethanol pretreatment resulted in increases of 3.8% and 7.6%.
The main objective of this study was to investigate the relationships between stress-wave velocity measured in logs and small clear specimens and the bending strength of Pinus massoniana trees planted in northern Vietnam. Stress-wave velocity (SWVL) and green wood density (WDL) were measured on logs collected from different heightlevels of 23-year-olds P. massonianatrees. Stress-wave velocity (SWVS), wood density (WDS), and bending strength (MOR) were subsequently determined on small clear specimens prepared from the logs. Regression analyses revealed significant correlations between SWVL and MOR (r = 0.73, P < 0.001) and between SWVS and MOR (r = 0.80, P < 0.001). These results show that stress-wave velocity measurements, whether taken on logs or small specimens, are effective for segregating P. massoniana lumber resources based on MOR. A more accurate prediction of strength was obtained when stress-wave velocity and log or specimen wood density were used together to calculate the dynamic modulus of elasticity of logs (DMOEL) or specimens (DMOES), respectively. The correlation coefficients were 0.82 (P < 0.001) between DMOEL and MOR, and 0.93 (P < 0.001) between DMOES and MOR.
This study evaluated the characteristics of Indonesian commercial wood species modified through the yakisugi surface finishing technique combined with coating application. Four wood species, teak (Tectona grandis), pine (Pinus merkusii), mindi (Melia azedarach), and mahogany (Swietenia mahagoni), were treated using a mini butane torch to produce charred surfaces either with or without the removal of carbon layers, followed by transparent exterior coating. The treatments were assessed for volumetric swelling, water absorption, and termite resistance through a 12-week graveyard test. Results showed that combining surface charring and coating improved dimensional stability and termite resistance compared to untreated wood. The durability class of teak and pine increased to class II, while mindi and mahogany showed no significant changes. The findings suggest that surface charring combined with coating provides a simple, practical, and effective finishing method to enhance the performance of tropical commercial woods.
This paper presents a validated finite element model of a cross-laminated timber (CLT) wall-to-floor connection and compares its predictions with results from a full-scale shear wall test. The CLT wall and floor panels are modelled as orthotropic shell elements, while the discrete connectors (tension anchors, angle brackets and the screw connection between floor panels) are represented by line hinges with nonlinear load-slip relationships.These relationships are derived from dedicated component tests on tension anchors, shear brackets and screw head embedment. The model is analysed in nonlinear static steps corresponding to the experimental loading sequence. Vertical slip along the wall-to-floor interfaces and the global lateral load-displacement response of the wall are extracted and compared with measurements. The results show that the simplified line-hinge representation reproduces both the global stiffness and the local deformation pattern in the joints with satisfactory accuracy for design-oriented analyses.
The paper is focused on monitoring the impact of corn kernel's casing content added to old corrugated containers on density, brightness, ultimate tensile load, tensile index, tensile energy absorption, breaking length, tensile strength, relative elongation, air resistance of paper sheet according to Gurley and zero-span tensile strength. A content of 40 % and 60 % corn kernel's casing added to secondary fiber based on old corrugated containers was tested. Suspensionsprepared by acidification and beating were subjected to chelation and three-stage bleaching.The bleaching method consisting of three steps was applied in two series-acidified and beaten pulp suspension with Schopper-Riegler (degrees SR) beating degree at level of 72 degrees SR.The first bleaching step includedperoxide bleaching with added sodium hydroxide, chlorine dioxide bleaching and peroxide bleaching in an alkaline environment. The effect of chemical and hydro-mechanical treatment on the resulting physical and mechanical characteristics of prepared paper sheets was investigated.
Culms of three bamboo species, Bambusa vulgaris, B. maculata, and Gigantochloa atter, collected from four natural stands in Lombok Island, Indonesia, were decayed by a white-rot fungus, Trametes versicolor, for 90 days. The obtained data were analysed by a mixed-effect model with a random effect of the sites to evaluate the geographic variations of decay resistance of the culms. Mean mass loss values were 16.3% for B. vulgaris, 20.2% for B. maculata, and 13.8% for G. atter. No significant difference in mass loss was found among the three species. Mass loss was positively correlated with amounts of hot-water extracts and organic solvent extracts in B. vulgaris, and with amounts of hot-water extracts and 1% NaOH extracts in B. maculata. As a result of mixed-effect modelling, the variance component ratio of the sites ranged from about 10 to 30%, suggesting that geographic variation was recognized in the culm decay resistance.
The article presents research focused on the properties and mechanical activation of waste dust (WDC) generated during the processing of cement-bonded particle boards (CBPs). Six samples of WDC were taken directly from the CBP manufacturer CIDEM Hranice, a.s.during 2024. The properties ofWDC samples were analysed with regards to its application in CBP as an active component of cement matrix. The particle size, distribution, specific surface area, density, wood content, loss on ignition, chemical and mineralogical composition, pH, microstructure, etc. were assessed. The WDC samples were then subjected to homogenization and mechanical activation in a planetary mill. The potential of mechanically activated WDC from CBP processing as a partial cement substitute was proved. While the activated WDC in an amount of 20% showed a 32% decrease in compressive strength, an 19% increase in flexural strength was also observed. As part of follow-up research, the activation process will be optimized by increasing the intensity and duration of grinding.
