Volume 21 Issue 3

Fast-growing species have potential as alternative timber species for sustainable wood utilization in tropical regions. This study evaluated the biological performance and mechanical properties of three Meliaceae species: Swietenia macrophylla, Toona ciliata, and Azadirachta indica. Resistance to subterranean termites and wood-decay fungi was assessed in accordance with Japanese Industrial Standards (JIS). In addition, Brinell hardness and bending properties were measured. All three species showed high resistance to termite attack; however, decay resistance was species dependent. S. macrophylla and T. ciliata exhibited relatively high resistance to both white-rot and brown-rot fungi, whereas A. indica showed high mass loss despite having comparable density to the other species. The fungal susceptibility of A. indica could not be explained by density or hardness alone and was likely associated with differences in chemical durability including extractive composition. T. ciliata showed mechanical properties comparable to those of S. macrophylla, a high-value timber widely used in various applications. These results indicate that T. ciliata has strong potential as an alternative timber resource in tropical regions. Its biological performance and mechanical properties may support sustainable wood utilization and diversified local land-use systems.

Establishing an economically efficient supply chain for biomass feedstock is a critical prerequisite for achieving large-scale bioenergy development under China’s “dual carbon” strategy. Focusing on agro-forestry residue feedstocks, this paper systematically reviews the technologies and models for the key stages of their collection, storage, and transportation (CST) system. The inherent physicochemical characteristics of biomass, such as low bulk density and high moisture content, constitute a fundamental physical bottleneck that constrains its economic viability. To this end, pretreatment technologies, with densification at their core, are widely recognized as a critical technological stage for enhancing logistics efficiency and achieving value addition. In contrast to the technological optimization of individual stages, systemic integration strategies—such as establishing a hybrid “decentralized-centralized” supply chain model and employing multi-modal transport—represent a more effective pathway to achieving whole-chain cost reduction and efficiency enhancement. Through a systematic integration of research in this field, this paper emphasizes that the key to resolving CST bottlenecks lies in adopting a whole-chain perspective that involves the deep coupling of essential pretreatment technologies with innovative supply chain organizational models.

A comparative study on the pyrolysis of untreated (SA) and NaOH-treated (SB) corn cob-husk blends (1:1, wt%) was conducted to elucidate their kinetic, thermodynamic, and mechanistic characteristics. The NaOH treatment was performed using 10 wt% NaOH solution for 2 h. Thermogravimetric analysis (TGA) was carried out over a temperature range of 50 to 600 °C, and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was performed at 550 °C. The Kissinger-Akahira-Sunose (KAS) and Friedman (FR) isoconversional methods were used to evaluate the activation energies and thermodynamic parameters (pre-exponential factor, Gibbs free energy, enthalpy, and entropy). The minor discrepancies between activation energy (E_α) and enthalpy change (ΔH) (< 6 kJ/mol) for both SA and SB suggest a high potential for biomass energy utilization. Notably, the NaOH treatment resulted in a downward shift in pyrolysis temperature and a lower average activation energy for SB, indicating a thermodynamically more favorable pathway. Mechanistically, the Criado method confirmed that SA follows a three-dimensional diffusion model (D3) initially (Zone I), transitioning to a random nucleation model (F1) beyond approximately 325 °C (Zone II), while SB consistently adheres to the D3 model. Additionally, Py-GC/MS analysis revealed that NaOH treatment, despite reducing bio-oil yield, noticeably enhanced biochar formation.

Plant-derived metabolites have attracted considerable attention with increasing interest in sustainable, bio-based resources for biological applications. HPLC analysis of unripe Ricinus communis fruits revealed a rich profile of phenolic compounds, with hesperetin (42400 µg/g) and chlorogenic acid (14300 µg/g). The extract exhibited antimicrobial activity. It produced inhibition zones of 23 to 31 mm for examined bacteria and 32 mm against Candida albicans, with minimum inhibitory concentrations as low as 15.6 µg/mL. Biofilm formation was inhibited by up to 97.8%. Cytotoxic evaluation showed anticancer activity against a human epidermoid carcinoma cell line (A431), with an IC₅₀ of 76.8 µg/mL compared to 359 µg/mL for normal HFB4 cells. Antibacterial and anticancer potential of hesperetin (main constituent of unripe R. communis fruits) through molecular docking against PBP2a from S. aureus (PDB ID: 4CJN) and EGFR kinase domain (PDB ID: 2GS6) were reported. Hesperetin exhibited favorable binding toward both targets, with docking scores ranging from -5.12 to -5.47 kcal/mol for PBP2a and -5.98 to -6.53 kcal/mol for EGFR. Key hydrogen bonding interactions were observed with GLN521 in PBP2a and ASP831 in EGFR, indicating stable ligand-protein complexes. Notably, hesperetin demonstrated stronger binding affinity toward EGFR, suggesting enhanced anticancer potential. Docking-supported hesperetin-rich extract exhibited antimicrobial resistance inhibition and selective anticancer activity.

Paper is one of the most recycled materials globally. In the United States, the average recycling rate was 60 to 64% in 2024. In response to sustainability goals, producers are increasingly incorporating recycled fibers over virgin wood. This study evaluates the repulpability and fiber characteristics of various paper grades using laboratory repulping and screening. Tissue paper, used brown kraft, Old Corrugated Containers and Sorted Clean News showed the highest repulping yields, above 80%, while Aseptic Packaging, Sorted Office Paper, magazines presented the lowest yields on average at 60%. On average uncoated products demonstrate lower total ash content compared to coated products, except for printing grades and non-domestic containerboard. These results highlight the impact of fillers and coatings on fiber recovery. Fiber quality analysis revealed significant variation between grades, with tissue, Old Corrugated Containers, Sorted Clean News, printed unbleached board, aseptic packaging, and fiber cores displaying the greatest weighted fiber lengths (1.6–1.8 mm) and widths (20–33 µm). Lower fiber yield led to higher fiber costs for raw materials, which is essential to consider in fiber procurement cost analysis. These findings offer practical insights for optimizing recycled fiber use, balancing cost, and maintaining product quality.

Expanding the concept of medium-to large-scale timber buildings to public buildings and securing data on the environmental benefits of timber construction are necessary for its recognition as a green building. This study aimed to compare the greenhouse gas emissions over the entire life cycle of a timber-framed house based on a standard Korean design and a concrete house designed by converting a timber-framed house. Timber structures reduced greenhouse gas emissions relative to concrete structures, and this effect became more pronounced as the building size increased. Although the largest environmental impact over a building’s entire life cycle occurred during the use phase, a significant difference based on the structure was found in the material production phase. The wood structure was found to emit approximately 43 to 50% less greenhouse gas than the concrete structure during the material production phase. The difference in total emissions was the highest in the largest-scale model, at 52.6 tCO₂, showing the greatest effect when a concrete house was replaced with a wooden house. These results can be attributed to the low embodied carbon content of wood and its ability to store carbon ranging from 21 to 34 tCO₂, which delays greenhouse gas emissions.

Environmental applications of torrefied biomass may be severely limited by contamination with carcinogenic polychlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF), and dioxin-like biphenyls (dl-PCB). In this article, the first systematic assessment of the influence of heating rate (HR) and residence time (RT) on the evolution of PCDD/PCDF/dl-PCB loads in bark-derived chars produced via torrefaction is presented. Sixteen torrefied biomass variants were examined, produced at a fixed temperature of 260 °C under different HR and RT conditions. Short processing durations (≤ 60 min) were found to induce a twofold increase in torrefied biomass toxicity (up to 1.314 ± 0.197 ng-TEQ·kg^-1 88% DM; DM stands for the dry matter), driven by precursor-mediated formation of PCDD/PCDF/dl-PCB, whereas extended residence times were shown to progressively detoxify the torrefied biomass, ultimately restoring toxicity levels comparable with, or markedly below, those of the raw biomass (0.689 ± 0.103 ng-TEQ·kg^-1 88% DM). The formation pathways of PCDD/PCDF/dl-PCB were governed by HR, as evidenced by the distinct kinetic profile observed at 30 °C·min^-1, reflecting suppression of the precursor-driven pathway, and by the newly identified “delay effect” of toxicity increase at 50 °C·min^-1 conditions. Collectively, these findings demonstrate the critical influence of HR and RT on the optimization of torrefaction conditions to produce torrefied biomass with reduced PCDD/PCDF/dl-PCB contents.

Cellulose foams are potential sustainable alternatives for packaging, thermal insulation, and acoustic applications due to their porous structure and renewable origin. Besides good mechanical properties and moisture control, antimicrobial performance is essential for applications involving contact with moisture and organic matter, such as food packaging and medical materials. This study investigates the antibacterial, antifungal, and soil biodegradation behavior of cellulose foams coated with a thin layer (approximately 5 g/m²) of xylan hemicellulose and its modified derivatives, including acetylated and AKD (alkylketene dimer) modified xylan. The results showed that foams treated with acetylated xylan exhibited the highest antibacterial activity, with about 58% inhibition of Bacillus sp species after 24 h at 27 °C. A slight antifungal effect was also observed, with delayed growth of Aspergillus and Penicillium species. Both coating composition and xylan modification significantly affected the degradation kinetics.

Surface roughness plays a critical role in determining the performance and quality of paper products; however, its accurate determination depends strongly on the geometry of the stylus used in contact profilometry. Herein, the effect of stylus-tip size on surface roughness characterization was evaluated along with the suitability of fractal dimension (FD) analysis as a supplementary metric. Styluses with tip radii ranging from 0.25 to 1.75 mm were examined, and a 0.5-mm stylus tip (0.5R) yielded the most stable and reliable surface roughness measurements under a constant contact force of 5 gf. Coating considerably reduced surface roughness fluctuations, with the roughness mean absolute deviation (RMAD) decreasing by 78%. A comparison between a 0.5R conical stylus and a pyramidal stylus showed strong agreement in the R_a and RMAD values, confirming that the conical design maintained minimal contact area. High-resolution profilometry (0.1-μm spacing distance and 200,000 data points per scan) enabled the computation of FD via power spectral density analysis. FD values approached 2 for coated paper, reflecting a transition from line-dominated to more areal surface structures. These findings indicate that stylus selection critically affects surface roughness characterizations and that FD serves as a useful complementary descriptor for surface roughness changes.

Mechanical, microstructural, and hygrothermal behaviours were studied for hybrid epoxy composites reinforced with Borassus flabellifer fruit fiber (BFF), snake grass fiber (SGF), and gum Arabic. Six composites were fabricated with varying BFF-SGF ratios while maintaining constant epoxy (60%) and gum Arabic (10%) content. The composites were evaluated for tensile, flexural, impact, hardness, interlaminar shear strength (ILSS), density, water absorption, thickness swelling, and microstructural morphology using scanning electron microscopy (SEM). Hybridization significantly improved the overall structural performance of the composites. Among all compositions, the C3 composite (15% BFF / 15% SGF / 10% gum Arabic) exhibited the highest tensile strength (72 MPa), flexural strength (89 MPa), impact strength (28 kJ/m²), hardness (79 Shore D), ILSS (42 MPa), and density (1.21 g/cm³), and the lowest water absorption (6.1%) and minimum thickness swelling (1.53%) after 72 h. SEM analysis revealed improved fiber-matrix interfacial bonding, reduced void content, and uniform gum dispersion in the hybrid composites, which contributed to their superior performance. In contrast, single-fiber and gum-free composites demonstrated lower mechanical and hygrothermal performance due to weaker interfacial adhesion and non-uniform stress transfer. These findings indicate that BFF-SGF hybrid composites are promising materials for lightweight structural and semi-structural applications.