Research Articles

Engineered laminated bamboo plays a crucial role in structural applications, addressing challenges such as bamboo’s natural variability, species differences, adhesives, and loading direction. This study examines the bending performance of three-layered laminated bamboo configurations using two species, Gigantochloa scortechinii and G. levis, bonded with phenol-resorcinol-formaldehyde (PRF) and polyurethane (PUR) adhesives. Laminated bamboo was assembled with lay-up patterns (parallel and perpendicular) and arrangements (vertical, horizontal, and mixed). Four-point bending tests under flatwise and edgewise loading were used to determine flexural performance and failure modes. Results showed that PUR-bonded bamboo had lower thickness swelling (TS) and water absorption (WA). While bamboo species did not significantly affect bending performance, the adhesive type, lay-up pattern, and arrangement were influential. Flatwise loading improved the modulus of elasticity (MOE) by 5% but reduced the modulus of rupture (MOR) by 10% compared to    edgewise loading. PRF-bonded bamboo outperformed PUR in strength, making it preferable for structural use. Vertical arrangements with PRF and PUR adhesives yielded optimal bending performance, emphasizing the importance of adhesive selection and configuration in enhancing laminated bamboo’s structural properties.

Indonesian agriculture faces multifaceted challenges, particularly the need to enhance productivity while maintaining environmental sustainability to ensure high-quality food production. Soil degradation and excessive use of chemical fertilizers have contributed significantly to declining soil fertility and land degradation. This study aims to evaluate the effectiveness of biochar and compost derived from lignocellulosic baglog, spent substrate from Ganoderma lucidum mushroom cultivation, to improve soil quality and fertility, especially under sub-optimal soil conditions. The treatments were tested on tomato plants using different application rates. A factorial Completely Randomized Design (CRD) was employed, comprising two factors with three replications. The first factor was the baglog waste compost dosage at four levels: B0 (0 g/polybag), B1 (200 g/polybag), B2 (300 g/polybag), and B3 (400 g/polybag). The second factor was the biochar dosage, also at four levels: K0 (0 g/polybag), K1 (250 g/polybag), K2 (500 g/polybag), and K3 (750 g/polybag). Key growth parameters, plant height, number of leaves, stem diameter, and leaf area, showed notable improvement compared to control plants grown without biochar or baglog compost. Applying both in balanced amounts is essential to promote optimal tomato plant growth.

Sporisorium reilianum is an emerging fungal resource rich in dietary fiber (DF), but conventional extraction yields suboptimal functionality. Using Sporisorium reilianum as raw material, the extraction process of modified dietary fiber (DF) was optimized through response surface methodology by adjusting the compound enzyme concentration, enzymatic hydrolysis time, material-to-liquid ratio, pH, and temperature. The optimal modification conditions for xylanase were a material-to-liquid ratio of 1:14.8 (g/mL), enzymatic hydrolysis temperature of 63 ℃, and pH of 6.24, with an average yield of modified soluble DF (S-SDF) of 15.1%. The swelling power, water-holding capacity, and oil-holding capacity of S-SDF were significantly higher than those of unmodified SDF. The overall adsorption capacities for cholesterol and sodium cholate of S-SDF and modified insoluble DF (S-IDF) were higher than those of unmodified IDF and SDF. The glucose adsorption capacity followed the order: S-IDF > IDF > S-SDF > SDF, and it exhibited dose-dependence. The modified DF still retained crystallinity having the same crystalline form. The monosaccharides remained predominantly composed of glucose. The modified DF showed superior adsorption capacities, enabling applications in cholesterol-lowering foods and gut health products.

The sound absorption properties of shredded paper wastes (SPW) were evaluated. Two impedance tubes (large and small) were used to measure the sound absorption coefficient of different thicknesses of SPW sound-absorber (20, 40, 60, 80, and 100 mm). As the thickness of the SPW sound-absorber increased, the optimum sound absorption coefficient was shifted to a lower frequency direction. Based on the KS F 3503 (2002) standard, the sound absorption coefficients were 0.3 M for 20 mm, 0.5 M for 40 mm and 60 mm, and 0.7 M for both 80 mm and 100 mm. The sound absorption properties of this SPW showed comparable or better performance than other eco-friendly fibrous sound absorbers. SPW has not been previously considered for recycling applications. The findings imply that SPW has good sound absorption properties and can thus be employed as a cost-effective and environmentally friendly sound-absorbing material.

A Scotch pine wood annual ring (AR) structure was modeled using AutoCAD and SolidWorks software. The same AR was separately modeled to create earlywood (EW), transition wood (TW), and latewood (LW). All 3D models were additively manufactured using Hyper PLA material and Creality 3D printer. Compression tests were performed to obtain load-deformation curves. The maximum force, compression strength (CS), and deformation at 500N load were determined. The EW presented the highest deformation while LW presented the highest CS. The TW and AR displayed intermediate behaviors. Finite Element Modeling and Analysis (FEM&A) was performed to compare with the experimental results. The numerical results presented considerable high deviations from the experiment. Around 78.7%, 41.7%, 89.3%, and 52% differences were observed for AR, EW, TW, and LW, respectively. Therefore, the capability of the model for prediction of mechanical behavior was not found to be successful. The essential reason for these discrepancies is the contrast between the orthotropic nature of wood and partially anisotropic nature of 3D printed models even if the filament is isotropic material. However, it should be taken into consideration that such high differences are not abnormal for the wood material even if the tested samples belong to the same log because of the variations in the material due to sampling details such as cutting location, orientation, etc. Furthermore, when considering the 3D printing parameters such as infill density, printing orientation, layer height, etc., the FEM&A results can be considered partially successful, although the differences were high.

Agro-industrial residues, derived from cereals, fruits, and vegetables, comprise non-consumable byproducts, including stems, leaves, peels, and seeds. Globally, approximately 3,045 million tons of such material is generated annually. In Mexico, the industrial crops coffee (Coffea spp.) and sugarcane (Saccharum spp.) yield residues rich in structural components, including lignin, cellulose, and hemicellulose. This study determined the physicochemical characteristics of cellulose isolated from these residues to formulate biodegradable polymers. Cellulose isolation was performed through chemical bleaching treatments, alkaline hydrolysis, and acid hydrolysis, yielding high-purity α-cellulose at 88.8% for coffee husks and 83.3% for sugarcane bagasse, with yields of 32.8% and 29.4%, respectively. Two biopolymers were developed: (A) 100% coffee husk cellulose and (B) a composite of 75% sugarcane bagasse fiber and 25% coffee husk cellulose. Biopolymer A demonstrated superior physicochemical properties, including moisture content, water vapor permeability, and solubility. Biodegradability assessments confirmed that both biopolymers were compostable within 110 days, exhibiting degradation extents of 84.4% (A) and 77.5% (B), primarily converting into organic matter and CO₂. These findings indicate that coffee and sugarcane agro-industrial residues are viable feedstocks for sustainable biopolymer production.

Lignocellulosic biomass, particularly softwoods such as pine, poses a significant challenge to enzymatic hydrolysis due to its high lignin content and complex structural rigidity. Although the application of steam explosion and alkaline pretreatment has gained widespread popularity for enhancing digestibility, the optimization of process parameters remains a formidable challenge due to the nonlinear interactions among variables. Machine learning is emerging as a promising solution to address these challenges, offering a viable alternative for predictive modeling and process control. In this study, an artificial neural network (ANN) model was developed to predict the enzymatic hydrolysis rate of steam-exploded pine wood subjected to mild alkaline (NaOH) pretreatment. The artificial neural network (ANN) was trained on experimental data encompassing three primary process variables: steam explosion time (1 to 5 min), NaOH concentration (0.5 to 2.0%), and chemical pretreatment time (12 to 24 h). The artificial neural network (ANN) model demonstrated the highest level of accuracy among the models evaluated, including random forest, support vector machine, and extreme gradient boosting. It attained a coefficient of determination (R²) of 0.9805. In conditions that were not optimized (1% NaOH, 24-hour treatment, 5 min steam explosion, without bark), a maximum hydrolysis of 93.9% was obtained.

A systematic approach was used to explore integrating regional cultural elements into public seating design, aiming to enhance the synergy between cultural heritage and contemporary aesthetics. Drawing inspiration from marbled porcelain from Dangyangyu, Henan Province, the study extracted core visual motifs and incorporated them into conceptual seating designs. The FKANO model was employed to identify and translate user needs into concrete design criteria, while the DEMATEL method was used to analyze causal relationships among these criteria to determine their relative importance. Based on these insights, three design proposals were developed. The TOPSIS was then applied to evaluate and optimize the alternatives. The optimal design is subsequently validated by expert evaluation, with an emphasis on environmental sustainability and ergonomic performance. The findings contribute a structured methodology for transforming regional culture into modern design language and provide a robust, evidence-based framework for evaluating public seating in urban environments, offering both theoretical and practical value.

The correlation between specific gravity and average annual ring width was studied for 15 major Korean tree species. In coniferous trees, species with narrower rings exhibited higher specific gravity, with strong correlations observed in Pinus densiflora (Gangwon), Larix kaempferi, and Pinus rigida. In deciduous trees, the correlation between specific gravity and annual ring width did not exhibit a consistent pattern based on the distinction between diffuse-porous and ring-porous species. The correlation of Liriodendron tulipifera (diffuse-porous species) and Quercus mongolica (ring-porous species) showed higher specific gravity with wider rings, whereas other species, such as Betula platyphylla (diffuse-porous species) and Robinia pseudoacacia (ring-porous species) exhibited the opposite trend. Therefore, the correlation in deciduous trees appears to be an inherent characteristic of each species rather than a result of porous type.

Based on the theory of stress wave propagation in solid media, this paper conceptualizes standing trees as a three-layer composite material comprising the pith, heartwood, and sapwood. Assuming that standing trees exhibit orthotropic anisotropy, the propagation process of stress waves within the trees is simulated and analyzed using the finite element simulation software. The paper investigates the effects of diameter at breast height (DBH) of 40-year-old standing larch trees and the proportional composition of pith, heartwood, and sapwood on the propagation of stress waves. The results reveal that, despite variations in DBH and the relative proportions of the three components, the overall propagation patterns of stress waves remain largely consistent across models. Initially, stress waves propagate in the form of an inclined curved surface. As the propagation distance increases, the inclination of the wavefront gradually decreases, eventually approaching a plane perpendicular to the longitudinal axis of the standing tree.  When the DBH increases from 30 cm to 50 cm, the stress wave velocity rises significantly from 3,450 m/s to 3,620 m/s. Additionally, as the proportion of sapwood increases, the velocity increases from 3,529 m/s to 3,916 m/s. A strong correlation is observed between wave velocity and the compositional ratio of the three components, with a correlation coefficient  (R²) of 0.98.