Volume 21 Issue 1

This study investigated the fabrication of C/SiO₂ ceramics using kraft pulp fibers (KF) and phosphorylated kraft pulp fibers (PKF) impregnated with a ceramic precursor via a sol-gel route. The rheological behaviour coupled to infrared spectroscopy of the ceramic precursor was examined to optimize the drying process of the impregnated preforms. Thermo-gravimetric analysis and scanning electron microscopy were used to study the thermal behaviour and micro-structure of the ceramics. The PKF exhibited a superior thermal stability, and enhanced fiber/ceramic interactions compared to untreated KF. The impact of the fiber functionalization and of the pre-pyrolysis of PKF on fiber/ceramic interactions was also explored. The in-situ formation of carbon fibers during heat treatment from PKF appears to be a more effective approach for developing future environmentally sustainable ceramic matrix composites (CMCs).

The material properties of softwood species affect the safety of building structures, and wood identification is a key factor in material certification in specific institutions for green building certification. This study investigated an efficient wood species identification algorithm, aiming to provide a reliable method for material selection in construction and decoration industries. Using microscopic cross-sectional images of 36 softwood species applied in construction and decoration as research objects, 11 classic deep learning models were employed for species classification, combined with class activation map analysis to examine the key structural features for species identification. Specifically, the model structure and advantages of Swin Transformer were highlighted, in which hierarchical feature extraction and shifted window attention mechanism enable multi-scale fusion of wood structural features, such as tracheids, within global contexts, thereby improving classification accuracy for wood cross-sectional images. Experimental results showed that the Swin Transformer model achieved the highest classification accuracy of 99.97%, with both precision and recall exceeding 99% and an F1 score of 99%. These findings validate that deep learning networks based on the Transformer framework can achieve reliable image classification performance in wood research.

To address the issue of bending deformation in panel furniture shelves under prolonged loading, this study developed a 3D-printed shelf reinforcer using polyamide 6 (PA6) filament via fused filament fabrication (FFF) technology. Initially, the bending performance of PA6 models was analysed under varying process parameters (infill structure, infill thickness, and extrusion flow rate) using the three-point bending method. Subsequently, the reinforcer was custom designed and 3D-printed according to the target shelf’s actual dimensions. Experimental results indicated that, among the three infill structures, the honeycomb infill structure exhibited the best bending performance, followed by the grid infill structure, and the line infill structure performed the worst. As infill thickness and extrusion flow rate increased, the bending performance of PA6 models progressively improved. The shelf reinforcer, 3D-printed with a honeycomb infill structure, 1.2 mm infill thickness, and 12 mm³/s extrusion flow rate, exhibited superior surface quality and achieved a tight fit with the shelf. This reinforcer effectively enhanced the shelf’s bending performance and load-bearing capacity, extending the furniture’s service life and providing practical reference for the rapid development of similar household items.

The influence of hybrid matrix composition was investigated relative to the mechanical properties of composite materials reinforced with poultry feathers and recovered paper. The matrix composition was modified by varying the proportion of natural dammar resin. The reinforcement remained the same across all formulations and was maintained at a constant 60% by weight in the composite, regardless of the matrix type. The materials were tested under tensile, compressive, and flexural loading, as well as for Shore D hardness and mechanical vibration behavior. It was found that increasing the dammar content enhanced the ductility of the material while reducing its fracture strength, regardless of the destructive testing method applied. In terms of hardness, a decrease was observed with higher dammar content. Additionally, in vibration analysis, an increase in the damping factor and a decrease in the natural frequency were noted as the dammar proportion increased. All these findings were statistically validated using a one-way ANOVA test.

Pleurotus ostreatus is a wood-decaying fungus capable of producing key enzymes for lignin degradation. Laccase (Lcc), manganese peroxidase (MnP), lignin peroxidase (LiP), and unspecific peroxygenase (UnP) activities of P. ostreatus grown on a wheat straw infusion medium enriched with malt extract and yeast extract (SMY) were studied. Growth kinetics and enzymatic parameters were also determined. Glucose medium was used as a control. The specific growth rate of P. ostreatus in SMY (0.62 h⁻¹) was more than twice as high as that shown in the control (0.24 h⁻¹). This fungus produced 5-fold higher biomass (15.7 g/L) in SMY medium than in the control (3 g/L). Lcc, MnP, LiP and UnP activities were approximately 67-,19-,11-, and 17-fold greater in SMY (3106, 4082, 1564, and 1883 U/L, respectively) than in the control (46, 213, 143, and 112 U/L respectively). P. ostreatus constitutively produced all the studied enzymes; however, the presence of wheat straw infusion components (i.e. phenolic compounds) in SMY enhanced the enzymes production. This is believed to be the first study to examine UnP production by P. ostreatus in an enriched natural medium. UnPs have been reported as promising enzymes for degradation of hazardous pollutants; however, there is still little information about their production.

Findings of an earlier study, “Improving Wood Surface Wettability through Gas-phase Ozone Treatment of Air-dry Wood,” demonstrated that the wood gas-phase ozone treatment enhances the wettability of wood by water, and thus potentially also the spread, absorption, and adhesion of water-based adhesives and coatings to the wood surfaces. This study extends that work by examining the effect of ozone treatment temperature and the wood moisture content on the wettability of ozone treated wood and bonding strength of phenol-formaldehyde (PF) adhesive. In the present study, both air-dry and wetted birch plywood and veneer were ozone-treated at 23 °C, 35 °C, and 55 °C for 10 and 30 minutes. The amount of reacted ozone increased with higher treatment temperature and with an increase in the wood moisture content. However, the reduction in the water contact angle was more pronounced for air-dry wood. Bonding tests showed that the ozone treatments substantially increased the PF adhesive bonding strength, and the bonding strength correlated negatively with the ozone-treated birch veneer water contact angle. The results suggest that both the treatment temperature and moisture content of the wood during the treatment influenced the ozone reactions with wood, and thus on wood wettability and PF adhesive bonding strength (192 / max. 200).

This study evaluated whether lipase enzymes could control pitch contamination in recycled pulps from a duplex board mill. The pitch contents of four recycled pulp types—old magazine paper (OMG), old book paper (OB), old newspaper (ONP), and old corrugated containers (OCC)—were analyzed using Sudan IV staining and image analysis of handsheets. The reaction times of lipase at varying dosages on pitch were monitored up to one hour under controlled conditions. The pitch contents, quantified in terms of total stained area and pitch-particle count, were substantially higher in OB and OCC than in ONP and OMG, with the latter showing the lowest contamination level. Lipase activity was most effective within the first 30 min. Thereafter, the pitch area reduction plateaued, and the larger aggregates fragmented, slightly increasing the particle count. It was inferred that a 30-min treatment time optimally balances efficiency and cost. Lipase treatment effectively reduced the pitch contents in both OMG and OCC pulps but was less efficient in OMG. The enzyme activity was apparently inhibited by the ink-derived compounds in OMG but was enhanced by the many lipase-accessible lipids in OCC, enabling a stronger, dose-dependent response. Lipase emerged as a promising biotechnological solution to pitch control in a duplex board mill.

The development of soybean meal (SM)-based adhesives with water resistance, heat tolerance, and magnetic-adsorbent functions is critical for expanding their applications as wood adhesives in hot and humid kitchen environments. A key goal is to enable magnetic storage systems such as knife holders and detachable shelves through localized adhesive application. However, the monofunctionality of existing bio-based adhesives limits their practical potential. In this study, micron-sized carbonyl iron powder (CIP) and nanoscale ferrosoferric oxide (Fe₃O₄) were introduced to confer multifunctionality to SM adhesives. Results indicated that the micron-scale dispersion of CIP markedly enhanced the heat resistance and wet-heat stability of SM adhesives through physical barrier effects, while optimizing magnetic attraction efficiency. In contrast, Fe₃O₄ nanoparticles achieved rapid magnetic response at low additive levels due to their high saturation magnetization, though nano-aggregation caused a sharp viscosity increase. Scenario-based validation confirmed that CIP-modified adhesives exhibit excellent structural stability in hot and humid kitchen environments, and they could withstand steam exposure, and retain magnetic adsorption properties.

Chitosan (CH) is a natural, biodegradable polymer derived from chitin. It is known for its broad-spectrum antimicrobial properties. Three fungal pathogens—Mucor circinelloides, Cladosporium herbarum, and Aspergillus niger—were isolated from decayed cucumbers. The CH and chitosan phosphate inhibited fungal growth in a concentration-dependent manner. The chitosan phosphate exhibited superior antifungal activity, achieving up to 84.2% inhibition at 2.75% (w/v). M. circinelloides was more sensitive than C. herbarum and A. niger. The CH was investigated for its antifungal potential via molecular docking against key protein targets from three pathogenic fungi: M. circinelloides (PDB: 6VRX), C. herbarum (PDB: 7KQV), and A. niger (PDB: 1GAL). Using MOE 2019 software, docking scores and interaction profiles were analyzed. Chitosan exhibited the most favorable binding affinity towards M. circinelloides with a docking score of -7.81 kcal/mol, followed by C. herbarum protein (PDB: 7KQV; -6.78 kcal/mol) and A. niger protein (PDB: 1GAL; -6.62 kcal/mol). Hydrogen bonding dominated the interactions, with critical residues including ASP 80 (6VRX), GLU 190 (7KQV), and ASP 416 (1GAL). These results suggest chitosan phosphate’s potential as a broad-spectrum antifungal agent targeting essential fungal enzymes.

The chemical composition, lignin structure, and extractive profiles of sapwood and heartwood were studied for 18-year-old Erythrophleum fordii trees to elucidate their chemical disparities and potential for high-value utilization. The cellulose, hemicellulose, and lignin contents were higher in sapwood than in heartwood. In contrast, heartwood exhibited significantly higher ash content, moisture content, and yields of various extractives, along with greater acidity. FTIR spectroscopy revealed SG-type lignin in both sapwood and heartwood, dominated by syringyl units. Heartwood formation did not alter the fundamental lignin structure but increased its condensation degree and reduced the characteristic hemicellulose absorbance. Notably, the heartwood was the primary site for bioactive constituent enrichment, with total phenolic and flavonoid contents (19.9 mg GAE/g DW and 36.5 mg RE/g DW, respectively) 4.3 and 5.6 times higher than those in sapwood. GC-MS analysis further showed that heartwood extractives were rich in terpenoids and sterols (e.g., vitamin E, stigmasterol, and β-sitosterol), compounds known for their antioxidant, cholesterol-lowering, and pharmaceutical properties. These findings underscore the potential of E. fordii heartwood for developing functional natural products and as a source of pharmaceutical raw materials.