Volume 21 Issue 2

In recent years, the variety of materials for fused layer modeling (FLM) 3D printing has expanded considerably, and new smart materials such as shape memory polymers (SMPs) have been added. Such SMPs enable so-called 4D printing, a programmable shape transformation of FLM 3D printed objects over time due to an external stimulus such as moisture or temperature. This paper addresses the processing of a specially fabricated climate-responsive wood/polylactic acid (PLA) composite using FLM 3D printing and the application of varying print directions for manufacturing programmable shape changing objects. In addition, this study is about developing a two-dimensional mathematical model based on the linear difference method to forecast accurately the moisture-induced deformation behaviour of 4D printed objects. Furthermore, the occurring deformations of the 4D printed objects were recorded using 3D scanning technology and compared with the simulated deformations from the mathematical model for validation purposes. With the help of the developed two-dimensional mathematical model, an exact reproduction of the deformation behaviour of 4D printed objects was made with a deviation percentage of always less than 6.5%.

This study evaluated and compared the biometric properties of wood from three fruit tree species: apricot, plum, and cherry. Three healthy trees from each species were randomly selected and sampled from gardens in Shahriyar, Tehran Province, Iran. Biometric analysis was conducted on fiber samples taken from radial positions at 25%, 50%, 75%, and 90% of the stem and branch radius. The Franklin method was used for fiber separation, and 30 fiber dimensions were measured per sample. The maximum fiber length was observed in apricot stem wood at 50% radius (1282 µm), and the minimum in apricot branch wood at 25% radius (835 µm). Across all three species, stem wood showed higher values for fiber length, slenderness coefficient, Runkel ratio, and rigidity ratio compared to branch wood. These properties generally increased from pith to bark, and the variations were statistically significant at the 99% confidence level.

In recent years, the number of university students in China has increased, while dormitory furniture often fails to meet students’ diverse needs. This study develops a hybrid FKANO-ANP-EW-TOPSIS model to design and evaluate dormitory beds, aiming to meet students’ diverse needs while promoting the sustainable development of dormitory furniture. First, demand indicators were identified through interviews and a literature review. The Fuzzy KANO (FKANO) model was used to screen these indicators. Key indicators were then integrated into a network model based on the Analytic Network Process (ANP) to analyze their weights and interdependencies. The Entropy Weight (EW) method was combined to determine the final weights for each indicator. The results show that structural stability, storage capacity, and modular design have the highest weights. Modular design emerged as the core element, with sustainability as the foundational element in the core relationship chain. Based on this, three sustainable, multifunctional wooden dormitory bed designs were proposed. The Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) was used to compare these designs with two popular products, identifying the optimal solution. This model offers a more comprehensive perspective for designing dormitory furniture, providing valuable insights for furniture manufacturers and designers.

For the industrial production of paperboard packaging, knowledge about the process window of the forming operation is crucial information. This study presents how blank moisturization shifts the process window of a compression drawing process. A hydraulic press was utilized to draw circular cups, and their quality was evaluated by counts of defects and wrinkles. The experimental part further includes measurements of the materials’ friction and tensile properties. It was found that both blank moisturization and increased blankholder force increased the wrinkle count and therefore improved the forming quality. However, the combination of high blankholder force and blank moisturization did not lead to superior forming quality. Rather, there were structural defects in the samples. A multilinear regression model was developed to predict wrinkle quantity based on tool temperature, material moisture content, and blankholder force.

The environmental and health concerns of traditional preservatives have led to investigations into an effective solution for protecting wood products with preservatives from natural sources. Guayule resin, derived from the Parthenium argentatum plant, has been reported to be effective as a wood preservative due to its bioactive properties. However, its high viscosity, limited penetration, and unknown leaching behavior may affect its durability and efficiency. This study investigated guayule resin concentration and solvent carrier efficacy. Yellow poplar and southern pine specimens were treated with guayule resin at four concentrations in three different solvents including acetone, ethyl acetate, and toluene. The leaching test was performed according to the AWPA E11-16 standard. Significant interaction between solvent type and concentrations of guayule resin were found in both species in which a lower mass loss was observed when 5% concentration of guayule combined with toluene as compared to any other guayule concentrations in southern pine. On yellow poplar specimens, 0.5% concentration of guayule in combination with toluene exhibited lower mass loss as compared to any other guayule concentration. In conclusion, toluene was found to be the best performing polar carrier system for guayule resin, considering its functionality and dose-dependence in both species.

The deflection behavior and safety performance were studied for medium-density fiberboard (MDF) and particleboard (PB) shelves reinforced with metal, polylactic acid (PLA), and polyethylene terephthalate glycol (PETG) pins. Experimental testing and finite element analysis (FEA) were used to assess the effects of shelf material, pin material, and filament color on the global mid-span deflection of the shelf, load capacity, and safety factors. Results indicated that MDF shelves exhibited lower deflection and higher load-bearing capacity than PB shelves, highlighting the importance of material density and homogeneity. Metal dowels provided the lowest deformation and highest safety factors for both shelf types, followed by PLA and PETG pins. Variations in filament color and pigment caused only minor differences in PLA pins, while finite element simulations closely matched the experimental results, confirming the reliability of computer-aided analysis for predicting deflection behavior and preventing material damage. Experiments conducted in accordance with BS EN 16122 (2012) and TS EN 9215 (2005) demonstrated that material and filament characteristics significantly affected deflection (R² = 96.1%, adjusted R² = 94.2%), and that MDF panels reinforced with high-strength, preferably metal, pins provide safe and durable shelf systems with a minimum safety factor of ≥ 2 to 3.

Filaments were produced with eight different blends for use in Fused Deposition Modeling (FDM) printers by adding 10% and 15% linden and oak wood flours as support materials to a polylactic acid (PLA) matrix. Wood polymer L-shaped connectors were printed from the produced filaments in the FDM printer. These L-shaped connectors were fixed to the particleboard corner joints to produce L-shaped corner joint specimens. These specimens were subjected to cross-compression and cross-tension tests using special molds in a universal testing machine to determine the effects of wood flour, wood species, and additive ratio on cross-compression and tensile moments. Thermogravimetric analysis, differential thermal analysis, and differential scanning calorimetric analyses were performed to determine the thermal properties of the wood-polymer composites, while scanning electron microscope imaging was performed to determine their morphological structures. Additionally, the tensile strength of the composites was also determined. The results showed that the mechanical properties of the samples produced with different wood flour types and additive ratios were lower than those of pure PLA. However, in diagonal compression and diagonal tensile tests conducted using L-joint elements obtained from different wood species and printed on an FDM printer.

Sustainable management of agricultural residues is essential to address environmental degradation and promote soil health, particularly in arid and semi-arid regions. Date palm (Phoenix dactylifera L.), which is widely cultivated in these areas, generates substantial organic waste, including leaves, stems, seeds, and fibers. Traditional disposal practices such as open burning and landfilling contribute to pollution and the loss of valuable organic matter. Composting offers a promising, environmentally friendly solution by converting date palm biomass into nutrient-rich organic amendments that improve soil structure, enhance fertility, and increase crop yields. This review examines the potential of composting as a sustainable strategy for valorizing date palm agro-waste. It discusses the composting process, nutrient content, and effects on soil properties, microbial communities, and plant growth. The review also highlights challenges such as quality control, scalability, and policy support, while emphasizing the role of composting in reducing chemical fertilizer use, enhancing carbon sequestration, and promoting circular agriculture systems.

The main objective of this research was to determine the retention properties of extracts obtained from the leaves of Liquidambar orientalis Mill., (belonging to  the class of medicinal aromatic plants) to organic (ecological) wood structures, thereby creating an ecological wood preservative that could be preferred in a wide variety of applications. Wood samples were taken from red pine trees in the Köyceğiz Agla region. Then, 1%, 3%, and 5% solutions of the extract were prepared. Vacuum method was used as the impregnation method. After impregnation and conditioning, the experimental and control samples were tested for mechanical properties such as bending strength, modulus of elasticity, compressive strength, and dynamic bending strength, while physical properties such as air-dry and specific gravity tests were conducted. The highest retention value was found at a 5% concentration (1.13%), the highest air-dry specific gravity value at a 1% concentration (0.56 g/cm³), and the highest air-dry specific gravity at a 1% concentration (0.53 g/cm³). Among the mechanical properties, the highest bending strength value was determined at a 5% concentration (1.13%), the highest modulus of elasticity at 1% (9145 N/mm²), and the dynamic bending strength at a 3% concentration (0.27 kgm/cm²).

Finite element analysis (FEA) was used to investigate the static structural behavior of the ‘Five-tier Outer Eave Column-head Dougong bracket’ of the Yanghe Tower from the Yuan Dynasty. Based on GB/T standard testing results for the mechanical properties of Pinus sylvestris, an improved ANSYS orthotropic anisotropic model was established. The Hill yield criterion was applied to characterise the wood’s plasticity. The model was calibrated against experimental results in the literature. Through simulations of vertical monotonic loading (Z-axis) and horizontal low-cycle cyclic loading (Y-axis and X-axis), the structure’s strength, deformation, and energy dissipation capacity were analysed. Results indicate that the maximum vertical bearing capacity at the interface between the Huagong-rear-end/Sandou interface reached 343 kN, with peak stress reaching 16.9 MPa. Horizontal loading produced symmetric hysteretic curves, with maximum horizontal thrusts of 737 kN (Y-axis) and 523 kN (X-axis). The ductility coefficients were 2.59 and 3.59 respectively, while equivalent viscous damping coefficients were 0.072 and 0.144. Vertical response conformed to a trilinear stiffness degradation model, whilst horizontal response followed a multilinear restoring force model. It was found that finite element analysis (FEA) provided an economical and reliable method for evaluating the mechanical performance of Dougong, offering significant reference value for the conservation of timber heritage structures.