Volume 21 Issue 1

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.

The shamisen is a three-stringed, plucked instrument that is used in a variety of genres, including folk music and kabuki theater. A PicoScope was used to obtain the signals from the shamisen. Open strings 1 and 2 exhibited discontinuities in the sequence of ascending notes. On string 1, B5 at fret 11 unexpectedly drops to C5 (instead of C6) at fret 12. On string 2, C6 at fret 17 drops to C♯5 (instead of C♯6) at fret 18. String 3 presented a continuous progression, ranging from C4 up to A5. The abrupt shifts from B5 to C5 and C6 to C♯5 on string 1 and 2 respectively results from the traditional Japanese approach to tuning (musicians emphasize relative intonation instead of conforming to equal-tempered pitch systems). Certain pitches may not hold functional significance within the melodic or harmonic framework, and their omission or alteration is consistent with historical performance practice. The variations in pitch captured in PicoScope data represent authentic outcomes of the shamisen’s culturally rooted tuning system and performance aesthetics. The PicoScope displayed the fundamental frequency one octave higher than the perceived pitch, while the gradient of the plotted partials frequency curves confirmed alignment with the actual sounding pitch.

Bamboo packing has been found to be a superior alternative to plastic packing for cooling towers, but traditional bamboo grid packing comprises numerous components, resulting in high production costs and low production efficiency. Therefore, a novel structured bamboo woven packing was designed in this study. The bamboo woven packing consisted solely of bamboo strips, which simplified the production process. The thermal performance of bamboo packing was systematically investigated. The results indicated that increasing the inlet air velocity and gas-liquid ratio enhanced the cooling water range and cooling efficiency, whereas a higher water drenching density had the opposite effect. The pressure drop increased upon increasing the inlet air velocity and water drenching density, while the influence of the gas-liquid ratio on pressure drop did not exhibit a discernible trend. A comparative analysis of the thermal performance of cooling towers utilizing bamboo woven packing and bamboo grid packing was also conducted under identical experimental conditions. The results showed that the cooling tower with bamboo woven packing exhibited a higher air velocity, a lower outlet water temperature, and superior cooling efficiency. Consequently, the newly designed bamboo woven packing outperformed traditional bamboo grid packing in terms of structural design, manufacturing process, and thermal performance.