Research Articles

Despite extensive research on anaerobic digestion (AD), the combined effects of intermittent stirring energy demand and substrate co-digestion on overall energy performance have remained insufficiently explored. This study evaluated the effects of intermittent stirring duration and the AD performance of cattle dung (CD), poultry droppings (PD), rabbit droppings (RD), and their mixtures on methane production and net energy recovery.  Experiments were conducted in 30 L laboratory-scale mechanically stirred batch anaerobic digesters operated under mesophilic conditions and intermittent stirring durations of 1, 2, and 3 h/day. Co-digestion clearly outperformed mono-digestion, achieving higher methane yields (up to 223 L/kg VS), improved biodegradability (>90%), methane-rich biogas, and shorter digestion times (18 days). Intermittent stirring duration significantly influenced performance; moderate stirring (2 h/day) was optimal for most binary mixtures, while higher stirring (3 h/day) enhanced methane yield in balanced ternary systems. Optimized co-digestion could reach up to 7.96 MJ/kg VS despite increased mixing energy use. The statistical analyses revealed strong interrelationships among process variables, identifying stirring duration and digestion time as key drivers of methane yield and net energy production. Artificial neural network (ANN) modeling successfully predicted methane production and net energy based on C/N ratio, stirring rate, and waste composition. The optimal ANN showed high accuracy (R=0.99).

To address the issue of insufficient desktop space in modern office and home environments, this study developed a side-mounted desktop organizer based on a pegboard. Comparative experiments on printing accuracy and mechanical performance were conducted using three commonly used 3D printing filaments in the market: polylactic acid (PLA), polyethylene terephthalate glycol (PETG), and acrylonitrile-butadiene-styrene (ABS). The results showed that among the X, Y, and Z directions, PLA specimens exhibited the smallest dimensional errors, PETG showed intermediate values, and ABS displayed the largest. In terms of tensile strength and elastic modulus, PLA specimens demonstrated the highest values, PETG ranked second, and ABS had the lowest. Therefore, PLA filament was selected as the printing material for the desktop organizer, and fused deposition modeling (FDM) technology was used to complete the 3D printing of the prototype. The 3D-printed desktop organizer features good surface quality and high assembly accuracy, effectively expanding the vertical storage space of the desk and enabling organized storage of small items, such as stationery and cables, demonstrating strong potential for application and promotion.

In the wood industry, warehouse layout decisions have a strong impact on production efficiency and workplace safety. This study presents a methodology that combines ERP-based historical movement data with measured process times to evaluate alternative warehouse layout versions. As a first step, products were grouped, their packaging and storage types were identified, and stock demand was calculated based on average and percentile values. A movement model was then used to assess layout options based on measured handling times and transport distances. Four layout versions were presented to the company management. For each version, the total daily net material handling time and required storage capacity were determined. The results showed that the originally planned block storage layout (V2) had a medium handling time and good feasibility but raised safety concerns. The V4 layout provided the most balanced option in terms of safety and capacity, while the finally selected V3 version—with a 4-meter aisle width—offered the lowest total handling time, which was a priority due to high production volume and fast warehouse servicing needs. This research demonstrates how can the Excel-based numerical modeling built on ERP data and process measurements, support warehouse layout decisions and improve operational performance and strategic planning.

Traditional furniture design relies heavily on designers’ prior knowledge and limited individual capacity, which often results in insufficient innovation capability and low product development efficiency. To overcome these limitations, this study introduces advanced Artificial Intelligence Generated Content (AIGC) technology and proposes an integrated creative design and evaluation framework for new Chinese-style furniture that combines Stable Diffusion (SD) with the CRITIC–VIKOR method. The proposed method aims to enhance research and development efficiency and creativity while enabling a comprehensive assessment of generated furniture design alternatives. Specifically, the SD model within the AIGC technology is employed to train and generate innovative furniture design images. After identifying affective words that represents user needs, the CRITIC–VIKOR method is applied to calculate the objective weights of user needs and to conduct a multi-criteria evaluation of the creative schemes, thereby determining the optimal scheme. The proposed method effectively integrates the strengths of generative technologies and quantitative decision-making approaches. It facilitates the rapid generation of diverse creative concepts while systematically selecting the optimal scheme that best satisfies user requirements, thereby promoting the development of the furniture industry and fostering the inheritance and innovative advancement of traditional culture.

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.

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.