Volume 21 Issue 2

The mechanical performance of fiber-based materials depends not only on strength but also on elongation, which is particularly critical in converting and end-use applications. Wood-fiber-based materials, such as thermomechanical pulp (TMP) paper webs, are typically brittle and exhibit low breaking strain. However, both dry and wet strengths can be significantly improved through hot-pressing, especially in the presence of lignin. This study examines the influence of hot-pressing time on the complete stress–strain behavior of calendered TMP webs. Dry samples showed only minor, systematic changes in mechanical properties with increasing pressing time at 200 °C. In contrast, wet samples exhibited a pronounced increase in breaking strain for pressing times exceeding 1 s, accompanied by increased wet specific strength and tensile energy absorption. Wet stiffness also increased beyond what could be explained by densification alone, indicating enhanced inter-fiber bonding. To elucidate these effects, X-ray microtomography combined with image analysis was used to characterize microstructural features, including porosity, pore size, surface roughness, sheet thickness, and fiber wall density as functions of pressing time. The results demonstrate that extended hot-pressing promotes microstructural consolidation and bonding mechanisms that improve mechanical performance under both dry and wet conditions.

Softness of hygiene paper encompasses bulk softness and surface softness components. Bulk softness is determined by bulk flexibility, which is the inverse of tensile stiffness, while surface softness is determined by surface roughness and friction. Although refining is essential for modifying fiber properties to achieve the desired tissue web characteristics, it increases tissue web density after drying, resulting in diminished bulk softness. This study explored methods to minimize strength loss while enhancing bulk softness by using pulps refined separately. The objective was to develop optimal pulp mixtures that maintain bulk softness and high tensile strength with improved surface softness. The results highlight the potential to optimize pulp mixtures for enhanced bulk softness and tensile strength and suggest that customizing the pulp conditions can effectively manage properties such as surface roughness and friction. The heterogeneity of pulps originating from separate refining systems is crucial for achieving targeted bulk and surface softness components.

The influence of changing climatic conditions was studied relative to strength parameters—tensile strength, modulus of elasticity, and internal cohesion—of joints between hardened epoxy casting resin and solid wood. Samples were exposed to various climatic conditions, including ageing simulation under normal conditions (25 °C, 30% humidity), and extreme conditions (50 °C, 90% humidity). The study also examined the impact of incorporating oak wood dust (0.05% by weight) as a bio-based additive into the epoxy matrix. Chemical resistance of the cured resin—with and without the additive—was evaluated using a modified Buchholz indentation test following exposure to a toluene–naphtha–ethanol solvent mixture. Moisture content was assessed. Alternating climatic conditions significantly impacted the strength parameters, with extreme temperatures and humidity levels reducing joint integrity. Mechanical stress further exacerbated this deterioration, underscoring the importance of environmental considerations in applying resin-wood composites. Furthermore, the addition of oak wood dust improved the chemical resistance of the epoxy resin, suggesting enhanced durability and interfacial bonding. Visual inspection of post-failure specimens revealed a higher prevalence of cohesive wood failures in oak, indicating superior bonding compared to meranti. These findings offer insights for appropriate use of epoxy–wood joints in furniture applications conditions.

Compressed hybrid composite laminates with a thickness of 3 mm were fabricated using a skin–core configuration, employing jute and glass fabrics as reinforcements and epoxy as the matrix material. The impact performance and damage mechanisms of the jute/glass hybrid composites were compared against jute/epoxy composites with the same and variable thicknesses under varying low-velocity impact energies. The incorporation of glass fabric significantly improved the impact resistance of the thinner hybrid laminates. At a higher impact energy of 15 J, the hybrid composites exhibited a rebounding response, indicating superior energy absorption and damage tolerance. Laser shearography was utilized to examine the internal damage evolution, while computed tomography (CT) scanning was employed to quantitatively assess damage. An increase of up to 86% in the maximum impact load was observed from the hybrid composites with thickness of 3 mm when compared with the jute/epoxy laminates. CT scan analysis revealed completely perforated failure in the jute/epoxy composites with progressive crack propagation at different depths. The hybrid composites primarily exhibited localized sliding damage accompanied by surface denting, as observed through shearography. The findings confirmed that jute/glass hybrid composites offered an enhanced low-velocity impact resistance when compared with the pristine jute composites.

Physical (thickness swelling) and mechanical (modulus of rupture, modulus of elasticity, and internal bond) properties of the particleboard samples produced by mixing spruce (Picea orientalis) particles and oak (Quercus pontica) leaves at various ratios were investigated. Chemical composition of oak leaves and spruce wood (holocellulose, cellulose, lignin, ash content, alcohol-benzene solubility, 1% NaOH solubility, hot and cold-water solubility) were determined. Single-layer test panels were produced using urea-formaldehyde adhesive. Increasing the oak leaf content in the furnish negatively affected the mechanical strength properties, while improving the thickness swelling resistance. However, the particleboard samples produced with 10% oak leaves addition met the minimum mechanical requirements for general uses. Overall, it was found that oak leaves could be used as an alternative supplementary raw material source in the particleboard industry when blended with wood particles.

Fuel characteristics were evaluated for bark from four coniferous tree species native to Türkiye (Calabrian pine, Black pine, Scotch pine, and Taurus cedar). Bark samples from varying elevations and age groups were analyzed through calorific value (kcal/kg), ash content (%), volatile organic compounds (VOC, %), sulfur emissions (SO_2, %), elemental ash composition, Fourier transform infrared (FT-IR) spectroscopy, and principal component analysis (PCA). All calorific values were determined on oven-dried samples. Calabrian pine had the highest higher heating value on a dry basis at 5044 kcal/kg, along with the lowest value for ash (1.55%), while Scotch pine exhibited the lowest energy value (4518 kcal/kg). Black pine, which had the highest ash content (3.84%), appeared less suitable as a fuel source. Sulphur emissions across all species were marginal (0.005% to 0.04%). Ash content increased with altitude in Calabrian pine, while the opposite trend was observed in larch. PCA results showed interspecific variations in mineral composition and combustion traits. In conclusion, Calabrian pine and Taurus cedar bark show strong potential as renewable and cost-effective biomass energy sources due to their favorable calorific and ash properties. However, environmental factors such as altitude remain determining factors in biomass fuel performance.

As the cradle of civilization, Egypt has historically been at the center of the development of writing supports, which were first developed from the local papyrus, but later gradually replaced by true paper. This paper delves into Egypt’s historic change in writing materials. Used for over 4,000 years since around 3000 BCE, papyrus was a central element in the administrative and religious activities of the ancient Egyptian civilization, and the method of its production was an industry secret. The advent of true paper in the 8^th century CE, which involved breaking down plant tissue to release fibers, marked the beginning of a cultural change that led to the phasing out of papyrus under Islamic rule. By the time the 12^th century CE came around, the making of papyrus had essentially stopped, as paper had taken over, being both more durable and versatile. This study investigates the following: the reign of papyrus; the history and material science of papyrus; the technological shift from lamination to maceration, and comparative analysis of writing supports.

Prepared orange peel biochar (OPB) was evaluated as a low-cost adsorbent for removing Pb(II) ions from aqueous solutions. The OPB was examined using scanning electron microscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis, and Brunauer-Emmett-Teller analysis to identify surface morphology, functional groups, thermal stability, and surface porosity responsible for adsorption, respectively. The biochar showed typical lignocellulosic decomposition behavior and exhibited a microporous surface whose hydroxyl, carbonyl, carboxylate, and phenolic groups allowed effective Pb²⁺ uptake. Batch studies revealed maximum Pb²⁺ at a pH 5, adsorbent dosage of 0.7 g, contact time of 80 min, adsorbate concentration of 150 mg/L, and temperature of 50 °C. The Langmuir isotherm revealed adsorption maximum capacity of the adsorbent to be 73.5 mg/g, while thermodynamics analysis showed that Pb(II) uptake was endothermic. These results demonstrate that orange-peel biochar can be an effective, environmentally friendly, and renewable adsorbent for lead ions in wastewater treatment.

Automated defect detection is crucial for particleboard manufacturing, enabling precise quality control and improved production efficiency. However, existing approaches face three key challenges: small-scale defects, low visual contrast between defects and surrounding regions, and severe texture interference from complex backgrounds, which collectively undermine feature extraction and multi-scale representation. To address these issues, this study developed DWBA-YOLO, a multi-scale surface defect detection network tailored for complex texture scenarios. First, an Adaptive Dual-layer Weighting Mechanism (ADWM) was introduced, where Intra-Feature Weighting suppresses texture-dominated channel responses while Cross-Feature Weighting adaptively calibrates contributions from different pyramid levels. Second, an Adaptive Spatial Feature Fusion head was designed to learn spatially varying fusion weights and to mitigate cross-scale inconsistencies while maintaining lightweight overhead. Third, Normalized Wasserstein Distance was incorporated to enhance small-scale defect localization. Extensive experiments demonstrated the effectiveness of the method. On a proprietary particleboard defect dataset, DWBA-YOLO improved recall by 4.7%, precision by 4.2%, mAP@50 by 3%, and mAP@50:95 by 2.5% compared with YOLOv8n, while reducing computational complexity by 43%. These results indicate that DWBA-YOLO is effective and practical for real-time particleboard defect detection.

Seaweed has gained significant attention due to its extensive use in nutraceuticals and pharmaceuticals. Therefore, this study was conducted to perform proximate analysis, screen and quantify phytochemicals, and analyze the pharmacological potential of Sargassum ilicifolium (S. ilicifolium) extract via antimicrobial, hypoglycemic, and antioxidant activities. The results of the proximate composition revealed 38.2±1.1% ash, 9.3±0.9% moisture, 23.4±1.1% protein, and 3.1±0.2% fat. The methanol extract increased the levels of alkaloids (26.3±0.9 g PE/g), phenols (145±3.1 mg GAE/g), and flavonoids (97.5±3.1 mg QE/g). The methanol extract exhibited strong activity, with a zone of inhibition of 27±2 mm against E. faecalis and a 22±0 mm zone of inhibition against S. aureus. The phytochemicals in the methanolic extract had a greater total antioxidant capacity (58.2±0.8%) than did the ethyl acetate extract (49.4±0.4%) and the water extract (44.6±0.3%) at 2.5 mg/mL The S. ilicifolium extract also exhibited α-glucosidase and α-amylase inhibitory activities. The seaweed inhibited tyrosinase activity in the ethyl acetate extract but not in the methanol or water extracts. The seaweed S. ilicifolium exhibited bioactivity and biotechnological potential, as evidenced by its antimicrobial, antioxidant, and hypoglycemic properties.