Research Articles

The mechanical behavior of hybrid composite materials was studied based on a matrix composed of 50 wt.% Abies alba exudate and 50 wt.% epoxy resin, reinforced with cotton and silk fabrics. Composite plates were manufactured using a hand lay-up technique with a 40/60 resin-to-reinforcement ratio. Mechanical characterization included tensile, flexural, vibration, and Shore D hardness tests, supported by statistical analysis using one-way ANOVA and Bonferroni post hoc comparisons. The results showed that the introduction of textile reinforcement significantly improved all investigated properties compared to the unreinforced hybrid resin. Cotton-reinforced composites exhibited the highest tensile and flexural strength, as well as the highest hardness values, indicating increased stiffness and load-bearing capacity. In contrast, silk-reinforced composites demonstrated superior deformation capacity and higher damping behavior, reflecting enhanced ductility and energy dissipation. Statistical analysis confirmed a highly significant influence of material configuration on all properties (p < 0.05). An exception was observed in flexural deformation, where no significant difference was found between cotton- and silk-reinforced composites, suggesting a similar global deformation response. The results demonstrate that hybrid epoxy systems modified with Abies alba exudate can be successfully used for the development of bio-based composites.

Ming-style armchairs represent a distinctive form of Chinese classical furniture, yet systematic methods for linking their morphological features to users’ affective responses remain limited. Conventional Kansei Engineering (KE) models treat design components as equally weighted, neglecting differences in visual attention. This study proposes an attention-weighted KE framework that integrates eye-tracking data with partial least squares (PLS) regression modelling. Five representative Ming-style armchairs were evaluated by 200 Generation Y participants across five Kansei dimensions using semantic differential scales. A subsequent eye-tracking experiment with 30 participants derived visual attention weights for nine morphological components via the coefficient of variation of total fixation duration. These weights were embedded into binary morphological coding and analysed using partial least squares (PLS) regression. Results indicated that the stretcher, apron, and spindle showed stronger associations with affective differentiation than the dominant backrest, which served as a stable perceptual anchor. Plain aprons and slightly curved spindles enhanced perceptions of simplicity and naturalness, while step-by-step stretchers and carved aprons were associated with complexity. The regression coefficients were translated into preference-avoidance design rules, suggesting that redesign may benefit from a two-fold strategy of preserving simple, recognisable treatment of the dominant category-defining component while concentrating tasteful elaboration on one selected secondary feature.

Carbon dioxide biomethanation offers a promising route for energy storage via biological conversion of renewable surplus electricity and CO₂ into methane. To improve the gas production efficiency and instability, bioaugmentation strategies are commonly employed by using biochar and trace elements individually. However, their coupled effect remains underexplored. In this study, the CM400 (biochar produced from cattle manure under 400 °C) showed superior performance in cumulative methane yield (138 mL·gVS⁻¹). Response surface optimization identified an optimal trace element combination (Fe: 15.1 mg·L⁻¹, Co: 1.5 mg·L⁻¹, Ni: 0.6 mg·L⁻¹), increasing methane yield by 12.9%. Subsequently, a novel modified biochar (CM400 pre-soaked in the optimal Fe/Co/Ni solution and pyrolyzed) was synthesized and significantly enhanced the volumetric methane production (VMP) by 19.8%. Experimentally, it enhanced the removal of total solids (TS), volatile solids (VS), and total chemical oxygen demand (TCOD) by 21.1%, 20.9%, and 3.4%, respectively, while strengthening pH buffering and preventing volatile fatty acid (VFA) accumulation. The modified biochar enriched electroactive bacteria (e.g., Synergistota, Chloroflexota) and key methanogens (Methanothrix). Collectively, these physiological and compositional changes are consistent with improved syntrophic metabolism and suggest the possible involvement of direct interspecies electron transfer.