Volume 21 Issue 1

Biomass densification and molding technology can compress and densify crushed materials into portable solid fuels with a certain shape and density. Such densification has the advantages of high combustion efficiency, high calorific value, environmental protection, and cleanliness. In recent years, scholars have used the finite element method and discrete element method to simulate biomass densification and molding technology, revealing the flow and deformation laws of materials in the biomass densification and molding process from different perspectives. This work has provided reference and guidance for the optimization of biomass densification and molding mechanism and molding dies. This article first reviews the basic ideas of finite element method, as well as the application of ANSYS and ABAQUS in biomass densification and molding technology. Secondly, it reviews the basic ideas of discrete element method and the application of EDEM and PFC in biomass densification and molding technology. Finally, it reviews the application of combined finite element method with discrete element method in biomass densification and molding technology. The content of the article has certain reference and guidance significance for the numerical simulation of future biomass densification and molding technology.

The rapid depletion of forest and water resources, drought, climate change, and the significant loss of freshwater resources, along with fires and wars, necessitate the creation of healthy materials and a hygienic structure, as well as the optimal use of wood. This study used various processes to obtain extracts from laurel leaf waste, which is known for its antioxidant/antibacterial properties. Subsequently, solutions of various concentrations (1%, 3%, and 5%) were prepared and the wood was impregnated using the immersion method (short, medium, and long-term). Tests were then conducted to determine the retention, specific density, bending strength, modulus of elasticity, compressive strength, and dynamic bending. The highest retention was determined at a 5% concentration for 6 h (2.50%), the highest air-dry specific density was determined at 5% for 6 h (0.68 g/cm³), and the highest bending strength was determined at 5% for 6 h (143 N/mm²). The extract prepared from ecological bay leaf plant waste with water creates a partially hygienic (antioxidant/antibacterial) framework for organic wood, benefiting human and environmental health.

Bacterial leaf blight (BLB), caused by Xanthomonas oryzae pv. oryzae (Xoo), threatens global rice production. The biopesticidal potential of six weed species, namely Parthenium hysterophorus, Ammi visnaga, Chenopodium album, Cannabis sativa, Amaranthus viridis, and Dysphania ambrosioides, was evaluated against Xoo. Crude extracts and their ethyl acetate and n-hexane fractions were tested using agar well diffusion, minimum inhibitory concentration (MIC) assays, and in vivo pot experiments under a factorial completely randomized design. C. sativa (1.13 g) and A. viridis (1.03 g) yielded the highest crude extracts. Parthenium hysterophorus n-hexane extract (63.7% inhibition at 100 ppm), D. ambrosioides n-hexane (55.2%), and A. visnaga n-hexane (167% at 25 ppm) showed significant antibacterial activity. Ethyl acetate fractions, particularly D. ambrosioides, reduced Xoo infection most effectively in vivo. Parthenium hysterophorus (31 to 70%) and A. viridis (59 to 65%) ethyl acetate extracts promoted seed germination and growth, while A. visnaga and D. ambrosioides n-hexane extracts reduced growth by 24 to 29% and 19 to 25%, respectively. Chenopodium album ethyl acetate extract increased chlorophyll content (61 to 68%). Electrolyte leakage was highest in P. hysterophorus crude extract (75%) and lowest in D. ambrosioides n-hexane (17%). These weed-derived extracts show promise for sustainable BLB management, warranting further compound isolation and field validation.

Wood surface defect detection confronts critical challenges including cross-scale feature extraction, excessive parametric burden, and inadequate small-target recognition. This study proposes MFWSD-YOLO, a lightweight multi-scale feature fusion detection algorithm to address these limitations. The algorithm introduces an adaptive downsampling module utilizing dual-path parallel processing to preserve spatial information, designs a shared convolution detection head enabling efficient cross-scale feature interactions, proposes a progressive feature integration block strengthening multi-scale semantic fusion, and embeds a local attention mechanism enhancing spatial modeling precision. Experimental validation demonstrates substantial enhancements, achieving mAP@0.5 and mAP@0.5:0.95 improvements of 8.90% and 5.17% respectively over baseline YOLOv12n. Concurrently, efficiency gains include 52.73% parameter reduction, 33.33% computational complexity decrease, and 50.94% model size compression, maintaining 195.6 frames per second inference capability. Cross-dataset validation substantiates robust generalization across diverse wood defect scenarios and industrial applications. These advances establish an effective computational solution for automated wood quality inspection within intelligent manufacturing environments.

The influence of two commercial fire-retardant formulations, HR Prof and Krovsan, and their mixtures on the thermal behavior and fire resistance of spruce wood was evaluated by simultaneous thermal analysis STA (namely TG/DTG/DSC) and radiant-heat exposure. The untreated wood exhibited the typical three-stage degradation of lignocellulosic material with a maximum mass-loss rate near 265 °C. All treated specimens showed delayed decomposition, reduced oxidation rate, and markedly higher residual mass at 700 °C. A strong correlation was found between thermogravimetric residue and the mass retained after radiant-heat testing, confirming that improved performance resulted from condensed-phase stabilization. Phosphorus–nitrogen components of HR Prof promoted early dehydration and intumescence, while boron–copper species in Krovsan reinforced the carbonized layer and limited oxidation at elevated temperature. The balanced mixture (50 HR – 50 KR) provided the most effective protection, combining early char formation with long-term stability. The synergistic action of HR Prof and Krovsan thus offers an efficient and environmentally acceptable strategy for enhancing the fire safety of spruce wood.

Uniaxial tensile tests of recycled waste wood plastic composites were conducted at 20, 40, and 60 °C. High density polyethylene (HDPE, 30%) was reinforced with poplar wood (50%), and calcium carbonate (15%), with 5% additives. The load values for three stress levels of 15%, 30%, and 45% were determined at each temperature. Subsequently, 24-h short-term creep tests of WPC were conducted under nine operating conditions. Both the ultimate strength and elastic modulus of the material was found to decrease with increasing temperature. The modulus and ultimate strength decreased from 3890 and 15.0 MPa at 20 °C to 1970 and 7.1 MPa at 60 ℃, respectively. Furthermore, the stress-strain curves of WPC specimens exhibit plastic behavior when the temperature exceeded 40 °C. The creep deformation of WPC was positively correlated with temperature and stress level. The Findley model exhibited distortion in fitting the creep performance of WPC only under the condition of 60 °C and 15% stress level. Conversely, the fractional-order model demonstrated a better fitting effect on the steady-state creep characteristics of WPC under this working condition.

The performance of medium density fiberboard (MDF) with styrene-based copolymers and glutaraldehyde was evaluated. Styrene/n-butyl acrylate (SBA), styrene maleic anhydride (SMA), and glutaraldehyde (GA) were tested at 1%, 2.5%, and 5% levels. Surface roughness parameters, mechanical and physical properties, and formaldehyde emission values were evaluated. Two different methods were used for panel preparation: surface application and mixing with UF resin. Different trends were observed depending on chemical types, chemical concentrations, and application methods. The surface roughness parameters (R_a, R_q, R_z) decreased with the application methods and chemicals used. The smoothest surfaces were obtained from groups with the chemicals compared to control groups. The surface application method yielded the most favorable results. The thickness swelling (TS) and water absorption (WA) values generally showed slight improvements, and better results were obtained with the UF-mixing method. Mechanical properties such as internal bond strength (IB), modulus of rupture (MOR), and modulus of elasticity (MOE) showed variations depending on the experimental parameters. In general, higher values were obtained for both application methods compared to control values. Free formaldehyde emission values were notably reduced with the UF-mixing method. In general, the use of SBA, SMA, and GA chemicals contributed to lower formaldehyde emission values.

Low-density polyethylene (LDPE)-based composites reinforced with lignosulfonate and lignin were developed to enhance mechanical and thermal properties while supporting sustainability. Tensile testing showed that increasing lignin concentration improved tensile strength, though no significant difference was observed between LL7.5 and LL10 due to possible lignin agglomeration. Differential Scanning Calorimetry (DSC) analysis revealed that all composites had a consistent melting point at 107 °C, while Thermogravimetric Analysis (TGA) showed similar thermal degradation patterns to LDPE (400–500 °C), with lignin-based fillers degrading at 200–400 °C. Melt Flow Rate (MFR) testing demonstrated a decreasing trend with higher lignin content, with LL0 showing the highest value (4.92 g/10 min) and LL10 the lowest (3.53 g/10 min). Fourier Transform Infrared Spectroscopy (FTIR) analysis before and after 30 days of sunlight exposure indicated no significant chemical changes, suggesting good environmental stability. These results demonstrate that incorporating lignosulfonate and lignin enhances both thermal stability and mechanical strength without compromising structural integrity under environmental exposure. The developed composites show promise for industrial applications requiring improved performance and eco-friendly materials.

There are ongoing efforts to use eco-friendly sound-absorbing materials to reduce noise pollution. Various sustainable sound-absorbing materials, including agricultural by-products, have been examined in previous research. This study focuses on using pistachio husks as a sustainable sound-absorbing material. To assess the performance, the sound absorption coefficient was determined by filling impedance tubes with pistachio husks to heights of 40, 60, 80, and 100 mm. The sound absorption peak was observed at 0.523 at 1,296 Hz at a fill height of 40 mm, and 0.736 at 532 Hz at a fill height of 100 mm. As the amount of pistachio husks in the impedance tube increased, the sound absorption performance at low frequencies improved. The noise reduction coefficients (NRCs) were 0.456 at 80 mm and 0.428 at 100 mm. This corresponds to a KS F 3503 grade of 0.5M, which shows that pistachio husks have sound absorption properties. However, the sound absorption performance of pistachio husks was inferior to that of other natural materials. Therefore, future research is required to improve the porosity of pistachio husks through various physical and chemical treatments.

Natural fibre composites are globally recognized for their sustainability and functionality, yet challenges such as poor interfacial bonding and high moisture absorption limit their performance. This study developed and characterized a polyester-based hybrid composite reinforced with silane-treated hemp fibres and Lansium parasiticum shell powder—an underutilized agricultural byproduct. The effects of reinforcement loading on mechanical, wear, dynamic mechanical, hydrophobic, and flammability behaviours were systematically investigated. The 3 vol% filler (T3) formulation exhibited maximum tensile and flexural strength, while 5 vol% enhanced hardness and wear resistance. Excess filler loading led to agglomeration and property deterioration. Silane treatment significantly improved fibre–matrix adhesion, thermal stability, and water repellence, as evidenced by increased contact angle and dynamic mechanical analysis results. Overall, the study demonstrated that silane-treated hybrid bio composites offer superior mechanical integrity, reduced moisture uptake, and improved thermal resistance. These findings highlight their potential for sustainable applications in automotive components, building panels, prosthetic sockets, and orthotic supports, contributing to lightweight and eco-friendly material development. This sustainable silane-treated hemp and bio-filler composite demonstrates potential as a next-generation material for lightweight biomedical support and rehabilitation applications in disability research.