Previous studies have demonstrated that bamboo exhibits distinct mechanical properties under tensile and compressive loading, characterized by differing moduli of elasticity. This asymmetry implies that the neutral axis of a bamboo cross-section under bending should not lie at mid-height. However, experimental validation of the neutral axis position remains limited. This study aims to comprehensively investigate the bending behavior of Wulung bamboo by considering the tensile and compressive elastic moduli parallel to the grain. Tensile, compressive, and flexural tests were performed according to ISO 22157:2019. The results revealed that the average tensile modulus of elasticity was 15,789 MPa for internodes and 13,716 MPa for nodes, while the average compressive modulus of elasticity was 21,270 MPa and 15,264 MPa, respectively. The neutral axis was consistently located below the geometric center of the cross-section, ranging from approximately -0.03D to -0.09D, where D is the average outer diameter of the bamboo culm. A modification factor for the tensile and compressive elasticity moduli was introduced to achieve internal force equilibrium in flexural analysis. A finite element analysis is recommended to further simulate the interaction between the position of the neutral axis, the modified tensile and compressive elastic moduli parallel to the grain, and the overall flexural behavior of the bamboo. ISO 22156:2021 remains applicable at the design stage, provided material behavior remains within the linear-elastic domain. However, a more detailed analysis of the stress-strain distribution along the fiber direction would help support and refine the structural design process.

This study investigates the use of carbon fiber (CF) and waste rubber (WR) as reinforcing materials to improve the physical properties of plywood. The impact of key factors-CF content, WR content, and CF length-on mechanical properties such as modulus of rupture (MOR), modulus of elasticity (MOE), and impact strength (IS) is explored. Water absorption (WA) and thickness swelling (TS) are also examined. Seven plywood samples were created by placing CF and WR as the core layer, with a urea-formaldehyde (70 wt.%) and polyurethane (30 wt.%) matrix reinforcing the veneer and core. The results show that CF significantly improves the physical properties at a 99% confidence level. Increasing CF volume and fiber length enhances mechanical properties, with plywood panels exhibiting better performance. The MOR decreased with WR incorporation, but MOE, WA, TS, and IS showed significant improvements, especially when 40 wt.% WR was added, which increased IS by 41.5%. As the comprehensive analysis from the studies, the various set of physical analysis shown the remarkable outcome such as synergistic effect of CF-WR acquires superior performance in engineering wood applications.

This study explores the use of binder-free rice-husk aggregates, a widely available agricultural byproduct, as a sustainable alternative for sound absorption in building applications. We assessed the material's efficacy by conducting experiments using cylindrical housings that were filled with rice husk aggregate. The aggregates were then tested in an impedance tube according to the ASTM E1050 standards in the frequency range of 400 to 6,000 Hz. The porosity was measured using an air pycnometer. The resulting average sound absorption coefficient (α_avg) was modeled in terms of the porosity and the density with quadratic equations. Thus, if either property is known, α_avg can be predicted. The highest recorded value of α_avg was 0.81. This study underscores the environmental and practical advantages of using binder-free rice husk, especially given its local availability and the absence of binders. The findings also open avenues for sustainable construction materials and could contribute to eco-friendly noise-control applications.

The transition toward sustainable agriculture requires developing eco-friendly inputs that reduce dependency on chemical fertilizers. In this study, a bioactive plant-nutrient solution was developed using steam-exploded biomass of Quercus mongolica (Mongolian oak). The effects of this solution were evaluated across a range of crops. The formulation, which is rich in natural polyphenols and low-molecular-weight organics, was applied under field conditions to various fruits (watermelons, tomatoes, strawberries, Campbell Early grapes, apples, and Shine Muscat grapes), and rice. This treatment resulted in significant improvement in crop quality and yield-related traits. In fruit crops, the proportion of fruits with a high sugar content increased, indicating enhanced carbohydrate accumulation. In rice, both the total polyphenol content and grain weight increased by approximately 37% and 10.5%, respectively, compared with the control. Microscopic analysis revealed an improved endosperm structure with a greater abundance of compound starch granules, suggesting better storage and textural properties. These effects were likely influenced by the antioxidant compounds present in the oak-derived formulation, which stimulated secondary metabolism and physiological robustness in plants. Our results demonstrate that the wood biomass-derived nutrient formulation tested herein can serve not only as an effective compound biostimulant but, additionally, as a practical input to promote functional food production. This novel approach offers a sustainable and resource-circular alternative to fertilization practice prevalent in conventional agriculture, thus supporting the valorization of forestry by-products while enhancing crop value and ecological compatibility.

The research evaluated physical properties, chemical constituents, and antimicrobial activity of Pinaceae oils (Picea koraiensis, Abies nephrolepis, Picea abies, and Tsuga sieboldii) to explore their potential as antibiotic alternatives. Leaf oils were extracted via hydrodistillation and assessed against Staphylococcus aureus and Klebsiella pneumoniae using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Among the oils, P. koraiensis oil exhibited the highest density (0.8969 ± 0.0027 g/mL) and refractive index (nD²⁰ = 1.4720 ± 0.0001), likely due to its major constituents, including limonene, camphene, and α-pinene. Oil yields ranged from 0.17 ± 0.03% to 3.07 ± 0.05%, with A. nephrolepis producing the highest yield. Pinaceae oils were rich in monoterpenes (84.98%-89.49%). Camphor (12.75%) was a major constituent of P. koraiensis oil, whereas A. nephrolepis oil contained unique terpenoids, including α-terpinyl acetate and the sesquiterpene nerolidol. A. nephrolepis and T. sieboldii oils showed strong antimicrobial activity against S. aureus (MIC: 2%-3%, MBC: 6%-8%), likely due to α-pinene and bornyl acetate. Both oils were also active against K. pneumoniae (A. nephrolepis: MIC 2%, MBC 3%; T. sieboldii: MIC 1%, MBC 2%), associated with abundant limonene (20.24%) and bornyl acetate (25%), respectively. Additionally, the strong antimicrobial activity of these oils may be attributed to their shared minor component, α-bisabolol, which was absent in the other oils. Therefore, A. nephrolepis and T. sieboldii oils show potential as natural preservatives or respiratory therapeutics, pending further pharmacological and toxicological validation. Physicochemical profiling of Pinaceae oils will aid quality control standard development.

Wood has gained attention for its value as an eco-friendly resource as well as its potential as an educational and cultural medium in the era of carbon neutrality. This study comprehensively analyzed public preferences for wood culture, demand for experience programs, and participation intentions in order to provide foundational data for developing policies aimed at facilitating more wood utilization. To this end, a survey was conducted on 2,500 adults across 17 metropolitan cities and provinces in South Korea to investigate public awareness of wood culture and demand for experience programs, seeking how to facilitate wood utilization. According to the results, the respondents expressed their preferences for creating furniture and accessories, expecting a variety of benefits from the experience, such as knowledge acquisition, enhanced creativity, and improved leisure quality. A particularly high demand for family participation and educational means for children was observed. In this regard, wood culture experience programs can be created and expanded by planning and operation, which can generate cognitive effects such as creativity and a sense of accomplishment from an educational perspective, beyond simple activities. Therefore, there should be more policy support, including employment, to ensure the stable establishment of a management system and the development of experts responsible for the systematic planning and operation of these programs.

This paper presents a fast Fourier transform-based autofocus technique for computer numerical control microscopy systems for the observation of fine anatomical structures in wood specimens. The proposed method enables systematic pausing of the motorized stage at predetermined X-Y coordinates, analysis of the high-frequency spectral components of the acquired images through fast Fourier transform processing to derive quantitative sharpness metrics, and subsequent implementation of a dual-stage coarse- and fine-search algorithm to determine the optimal Z-axis focal position prior to stage advancement under G-code control. This iterative protocol facilitates continuous focus optimization and ensures consistent image quality across specimens that exhibit inherent variations in surface topography. In addition, an intuitive graphical user interface was developed to provide streamlined operator control of the autofocus parameters and real-time performance monitoring capabilities. Experimental validation demonstrated that the proposed approach achieved a focusing accuracy within 10 ㎛ while consistently generating high-resolution microscopic images across diverse wood specimen types, with the system capable of processing five specimens in a single automated sequence.

With the recent increase in wood demand, stability in the log supply and effective resource management are becoming increasingly important. However, research focusing on the domestic log purchase of major species remains limited, particularly regarding time-series forecasting based on empirical data. Therefore, this study analyzed the log purchase of two major domestic species, Korean red pine (Pinus densiflora) and Japanese larch (Larix kaempferi), based on the Market Survey of Timber Products, and forecasted their log purchase trends from 2024 to 2030 using time series analysis. The results show that the log purchase of Korean red pine is projected to be approximately 745,000 m³ in 2030, with a confidence interval ranging from 497,000 to 995,000 m³. Although the absolute interval width is about 498,000 m³, the relative variability is only 33%, suggesting a relatively stable log purchase. In contrast, Japanese larch is forecasted at about 464,000 m³, with a confidence interval of 227,000 to 700,000 m³. The interval width is 473,000 m³, but the relative variability reaches 51%, indicating greater uncertainty in log purchase. These findings imply that while the Korean red pine is likely to maintain a stable supply base, the Japanese larch requires policy measures to be enacted, such as securing alternative species and diversifying supply channels. Overall, this study provides valuable baseline data for future forest resource management and policy formulation by presenting midterm forecasts of the log purchase of key species.

Large-cross-section timber is susceptible to defects such as surface checking and blue staining during the protraction process. Uncontrolled air drying without pre-treatment of these materials often leads to these defects and negatively impacts product quality and manufacturing costs. To address these issues, this study implemented real-time monitoring of temperature and moisture changes within the internal and external environments of the timber during drying. This research was conducted using Korean red pine (Pinus densiflora) round timber with a diameter of 45 cm under air-drying conditions. Untreated specimens were compared with those subjected to various surface pre-treatments (end sealing, end coating, and lateral coating). Changes in the amount of water released from timber were monitored using a load cell, while environmental and internal wood conditions were measured and recorded in real-time using a data logger with temperature and humidity sensors. The findings revealed that immediate air drying following debarking successfully mitigated blue staining, but it was consistently associated with the development of checks. Surface pre-treatments slowed the drying rate and consequently suppressed the occurrence of checking; however, defects were not entirely prevented. This study emphasizes the necessity of effective heat and moisture transfer control through appropriate physical quantity detection during large timber drying. These findings are expected to contribute to the optimization of drying processes and development of real-time monitoring technologies for industrial applications.

Wood fiber has been increasingly used as a sustainable and eco-friendly material; therefore, a drying process that can efficiently remove its high initial moisture content is required. To establish a more eco-friendly and efficient drying strategy, this study analyzed the changes in moisture content and energy efficiency during the drying of wood fiber using a fluidized bed dryer. Drying experiments were conducted on wood fiber for Medium-Density Fiberboard manufacturing (initial moisture content of 150%) under five different temperature conditions, ranging from 80℃-150℃. A comprehensive analysis was performed by integrating the change in moisture content over time, energy efficiency based on actual power consumption, and simulation results. The moisture content of the wood fiber decreased sharply in the first 30 s of drying. Subsequently, the drying rate decreased significantly, with the moisture content converged to a constant value specific for each temperature. The energy efficiency was almost entirely dependent on the processing time, decreasing in an inverse proportion. These results provide a foundation for optimizing industrial wood fiber drying to improve energy performance.