Research Articles

Based on UN Comtrade data (2004 to 2024), this paper constructs a directed weighted global corn trade network using complex network analysis to examine its spatiotemporal evolution, structural resilience, and recovery strategies. Findings reveal a multipolar trade pattern: exports shifted from the U.S. dominance toward competition among Brazil, France, South Africa, etc., while imports diversified from traditional Asian countries to include Mexico, Spain, Egypt, etc. The network became tighter and more efficient, with increasing density, clustering, average degree, and shorter average path length, showing small-world properties. The U.S., France, and South Africa exhibited strong intermediary control, Europe maintained influence advantages, Turkey and Thailand’s hub roles were enhanced. Resilience tests show improved resistance to random failures but high vulnerability to targeted attacks—core node failure causes sharp efficiency drops. Edge attacks are less disruptive due to route redundancy. Simulations show strong self-recovery under random shocks, yet deterministic hub attacks cause cliff-like collapse, requiring export diversification. This study provides a basis for trade evolution, risk identification, and supply chain resilience.

New methods for the synthesis of metal-containing composite materials based on natural polymers (chitosan, organosolv lignin, and nanocellulose) are proposed. Metal doping was performed by introducing salts of Cu(CH₃COO)₂, Ni(NO₃)₂, and Co(NO₃)₂ into a suspension of the initial biopolymer mixture. The obtained chitosan–cellulose (C/C) and chitosan–lignin (C/L) composites have a sponge-like structure and they are predominantly macroporous (cavity size from 50 to 70 μm). Analysis revealed the formation of three-dimensional structures with relatively loose packing, with a surface morphology resembling foam. The thermal stability of C/L biocomposites decreased in sequence: C/L > C/L/Ni > C/L/Cu > C/L/Сo. Cobalt-containing carbon composites obtained by carbonization of C/L and C/C samples at 600°C exhibited high specific surface area and pore volume. These composites were micro/mesoporous materials with mesopore fractions of 76.5% and 64.7%, respectively. Carbonization of the nickel-containing C/C biocomposite at 600 °C yielded a carbon composite with a predominantly microporous structure. The influence of the introduced metal nature, organic matrix composition, and carbonization temperature on the morphology and microstructure of the carbon composites was studied by SEM, XRD, and spectral chemical analysis methods. Samples carbonized at 400 to 600 °C consisted of three-dimensional structures of randomly linked film fragments with large cells. The distribution of the metal (Co, Ni, Cu) over the carbon support surface was found to be uniform.

Predicting oak wood quality is important for timber grading, forest management, and designing efficient wood-assessment workflows. This study compared destructive, semi-destructive, and dendrochronological approaches for evaluating wood quality in two contrasting stands in the Czech Republic: The SM stand is a sessile oak (Quercus petraea) upland forest and the JA stand is an English oak (Quercus robur) floodplain forest. The objective was to assess how effectively different measurement approaches capture variation in density and mechanical performance under realistic field conditions. Each species was sampled in a single representative stand; therefore, the study compares two stand-species combinations rather than isolating species effects from stand conditions. Sessile oak showed higher mean standard-specimen density (713 kg/m³ vs. 655 kg/m³), modulus of elasticity (9180 MPa vs. 8030 MPa), and modulus of rupture (93.6 MPa vs. 85.7 MPa) than English oak. Density was the strongest predictor of bending properties in both stand-species combinations, while latewood proportion improved interpretation of mechanical variation, especially when considered together with density. Compressive strength yielded the most consistent screening results, whereas Fractometer-derived outputs were more variable. The findings support density-based screening as the most robust practical approach, while also showing that compression-related relationships and dendrochronological indicators are more context-dependent.

The furniture industry, despite its high potential for creating added value, carries significant risks in terms of occupational health and safety. This study examines the furniture sector in Bursa—one of the key regions representing Türkiye’s furniture industry—focusing on micro, small, and medium-sized enterprises. A total of thirty enterprises were included in the field study, with ten enterprises being selected from each scale category. Within this scope, on-site measurement methods were utilized to identify workplace dust concentration-related occupational dust exposure factors associated with machines and production lines at each enterprise scale. Measurements were taken over a 15-minute period and repeated six times.  A range of variables was analyzed, including enterprise size, production line type, measurement location and machine type, as well as the occupational dust exposure limit values and the statistical significance of differences among these variables. Non-parametric analysis of variance tests and the Independent Samples Test Results Post-Hoc test were used for comparisons based on different variables. Medium-sized enterprises exhibited the highest level of dust-related risk. Paint shops and carpentry workshops were the riskiest units. Overall, the results indicate the need for more comprehensive preventive measures against physical hazards in the furniture manufacturing sector.

Moment–rotation (M–θ) relationships obtained from subassembly tests are often transferred directly to semi-rigid models of glued laminated timber (glulam) structures, although the identified response may depend on the loading arrangement. This study quantified that influence for a slotted-in steel-plate glulam–steel hub joint using refined three-dimensional finite-element models in strong-axis (MN) and weak-axis (MY) bending. Zero-preload three-point (3P) and four-point (4P) configurations were compared on a common joint-level basis, three 4P loading positions were assessed, and compression analyses were used to evaluate preload-induced eccentricity. After reconstruction of interface moments and local rotations, the initial-stiffness difference between 3P and 4P was 8.4% for MN and 4.0% for MY. Four-point loading reduced the shear-to-moment index from 0.317 to 0.023 in MN and from 0.146 to 0.006 in MY. Moving the loading points from 400 to 450 mm changed fitted stiffness by less than 0.1% while increasing actuator demand. At 100 kN axial compression, hub eccentricity reached 1.08 mm in MN and 15.77 mm in MY. The results demonstrate that loading configuration and preload-induced geometry should be considered when identifying rotational response for subsequent full-scale testing and semi-rigid modeling.

Biomass-fired thermal oil heaters are green and efficient heating devices that use heated thermal oil as the heat transfer medium. This study investigated how thermal oil thermophysical properties and heating temperature affect asphalt heating. A physical model incorporating thermal convection and conduction was established, computational fluid dynamics (CFD) simulations using hypothetical single-factor property combinations were conducted to analyze the effects of thermal oil density, specific heat capacity, and thermal conductivity. An independent experimental platform using a biomass thermal oil boiler and real thermal oils was constructed to examine the simulated property effects. Results show that the specific heat capacity and density of thermal oil dominate heat transfer during the early heating stage by altering the internal energy carried by the fluid. In contrast, the extremely low thermal conductivity of asphalt constitutes the primary bottleneck for system heat transfer, limiting the influence of thermal oil thermal conductivity on overall heating performance. Experimental trends support the simulated property effects. Within the tested property ranges, the influence ranking based on experimental temperature differences is: specific heat capacity > density > thermal conductivity. At 1000 s, the corresponding absolute temperature differences between the high- and low-parameter cases are 1.97, 0.91, and 0.2 °C. These findings provided theoretical support and design guidance for the matching of operating conditions and thermal oil selection in biomass-powered indirect heating systems.

Three-layer cross-laminated timber (CLT) panels were produced using Scots pine (Pinus sylvestris L.) for the outer layers and poplar (Populus) for the middle layer. Circular, rectangular, and trapezoidal geometric corrugates were applied to the middle layer; the aim was to determine the air-dry density, moisture content, thermal conductivity (λ), and thermal transmittance (U) values of the resulting panels under three different climatic conditions. The moisture content of the geometric corrugated CLT panels was higher than that of the control group. In contrast, the air-dry density values were approximately 15% lower than those of the control group. The lowest value of the thermal conductivity coefficient was obtained for the circular- corrugated panel at an average of 0.099 W/m·K, while this value was measured at 0.108 W/m·K for the control group. Similarly, the thermal transmittance coefficient also showed the lowest value, 2.026 W/m²·K, in the circular- corrugated panel. Both the corrugate geometry and ambient temperature had statistically significant effects on the heat conduction and thermal transmittance coefficients. However, the combined effect of corrugate geometry and ambient temperature was not statistically significant. Circular grooving improved the thermal performance of CLT panels, which were judged to be suitable for structural applications requiring thermal insulation.

Many countries are seeking to reduce their dependence on non-renewable energy sources, particularly fossil fuels. This study evaluated the chemical, energetic, and thermal characteristics of wood from non-commercial hybrid progenies and clones of Corymbia torelliana × C. henryi, C. torelliana × C. maculata, C. torelliana × C. citriodora × C. maculata, and C. torelliana × C. citriodora, at 3 and 4 years of age, to assess their potential for energy production. The genotypes exhibited variation in wood density, chemical composition, and energetic properties. Higher heating values ranged from 19.0 to 19.6 MJ kg^-1, although differences among genotypes were not statistically significant. Energy density ranged from 9.15 to 11.8 GJ m^-3, with clone CTC2 exhibiting the highest value (11.8 GJ m^-3) and the highest basic wood density (616 kg m^-3). Clone CTM2 stood out for its high extractive, lignin, and fixed carbon contents, supporting its potential for charcoal production. Thermogravimetric analysis showed that clone CTC6 had the highest residual mass (31.0%), indicating greater thermal stability under the tested conditions. Fourier-transform infrared spectroscopy identified functional groups associated with the main wood constituents, while X-ray diffraction revealed the highest crystallinity index in clone CTCM (38.4%). Overall, clones CTC2 and CTM2 showed promising wood properties for metallurgical charcoal production, highlighting the potential of non-commercial Corymbia genetic materials for energy applications.

To address the lack of quantitative environmental footprint assessment in design translation of intangible cultural heritage products, this study takes Dunhuang Nine-Colored Deer themed wood-based cultural and creative products as objects and constructs a green assessment path based on Analytic Hierarchy Process-Life Cycle Assessment (AHP-LCA). A three-level AHP model established by 30 interdisciplinary experts identified and prioritized the core bionic elements (galloping deer morphology: 0.344; mineral white: 0.121; line drawing outline: 0.057). According to ISO 14040 (2006) and ISO 14044 (2006) standards, dual-dimensional life cycle assessment is adopted to compare the baseline scheme and optimized scheme. The results show that the optimized scheme achieved 4.3% full life cycle carbon emission reduction, 52.8% raw material emission reduction, and 65% material recovery rate. The study shows that the AHP-LCA model can effectively balance cultural aesthetic demands and low-carbon properties of wood-based materials and provides a systematic methodological reference for green and sustainable development of biomass-based products.

A modular pallet-based press was designed and fabricated to integrate preheating, progressive compression, and cooling under restraint for solid-wood densification. Three separately driven units provided an effective pressing length of 950 mm and width of 140 mm per unit. The prototype accommodated a specified workpiece envelope of 110 mm in width, 55 mm in thickness, and 800 mm in length. The compression unit combined a horizontal lower pallet track with an inclined upper track. Thickness-limiting metal molds were introduced after preliminary trials revealed pallet impressions. In the reported application, Scots pine and black poplar were processed at a travel-speed setting of 0.50 m/min to a mold-defined thickness of 20 mm under load. Preheating and cooling involved stationary dwell periods controlled using exposed side-surface temperature readings. Thus, the implemented sequence was intermittent rather than uninterrupted through-feed. Pallet warm-up to 200 °C required approximately 15 min, and one operating session extended to 10 h. For the reference case involving 26.7 mm-thick Scots pine specimens, the calculated in-line residence time was 13.6 min, and the theoretical steady-state throughput of approximately 11.2 specimens/h was consistent with actual production. The documented design and operating sequence provide a basis for further instrumented performance evaluation and process optimization.