The Journal of the Korean Wood Science and Technology (JKWST) launched in 1973 as an official publication of the Korean Society of Wood Science and Technology has been served as a core of knowledges on wood science and technology.

Introductions: Ultrasonication can be used to synthesize nanosilica from silica derived from betung bamboo sticks and leaves. This study aimed to synthesize nanosilica from betung bamboo sticks and leaves by the use of ultrasonication and to characterize the nanosilica produced. Methods: The main materials used in this study were bamboo sticks and leaves. Betung bamboo sticks and leaves were sun-dried and then burned separately without adding fuel to produce charcoal. Then the produced charcoal was burned at a temperature of 700°C for 6 hours in a furnace to produce ash. Silica was extracted from furnace ash using reflux methods. The production of nanosilica from the silica derived from the betung bamboo sticks and leaves was carried out using ultrasonication. Results: The yield of silica from sticks and leaves was based on ash dry weight 45.73% and 79.93%, respectively. The nanosilica derived from betung bamboo sticks had a particle size in the range of 169.87– 1479.50 nm, with an average size of 502.35 nm and a particle dispersion index value of 0.1420. Nanosilica derived from betung bamboo leaves had a particle size in the range of 234.49– 851.36 nm, with an average size of 472.67 nm and a particle dispersion index value of 0.0670. Scanning electron microscopy analysis showed that silica from betung bamboo sticks and leaves still agglomerated. The particle size of silica could minimize through ultrasonication to synthesize nanosilica. Discussions: X-ray diffraction analysis showed that the structure of nanosilica differed from that of silica, and it appeared to be semicrystalline. The ultrasonication method for the synthesis of nanosilica derived from betung bamboo sticks and leaves ash can produce nanosilica that has a semicrystalline phase. The use of surfactants in the process can make the size of the nanosilica particles more uniform and reduce the size of the nanoparticles produced.

Mangium (Acacia mangium Willd.) is a fast-growing wood that is widely grown in Indonesia. The impregnation method is needed to improve the qualities of the wood. In this study, TiO₂ nanoparticle (79.17 nm) was produced using the hydrothermal method. The purpose of this study was to analyze the effect of TiO₂ nanoparticle impregnation on the density and dimensional stability of mangium and the effectiveness of the presence of TiO₂ nanoparticle in wood in degrading pollutants. The mangium samples (2 cm × 2 cm × 2 cm) were placed inside impregnation tube. The impregnation solutions included water (untreated), 1% TiO₂ nanoparticle, and 5% TiO₂ nanoparticles. The samples were analyzed for density, weight percent gain (WPG) dan bulking effect (BE). Samples were also analyzed by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). TiO₂ nanoparticle resulted in an increase in density, WPG, and BE-treated mangium. Based on XRD and FTIR results, TiO₂ nanoparticle was successfully impregnated into mangium wood. Scanning electron microscopy–energy-dispersive X-ray spectroscopy analysis indicated that TiO₂ nanoparticle covered the surface of the wood cells. The TiO₂-impregnated mangium wood has a higher photocatalyst activity than untreated, indicating better protection from UV radiation and pollutants.

A modelling method is proposed to highlight the effect of cambial age on the effective modulus of elasticity of laminated veneer lumber (LVL) according to bending direction and veneer thickness. This approach is relevant for industrial purposes in order to optimize the performance of LVL products. LVL is used increasingly in structural applications. It is obtained from a peeling process, where product’s properties depend on cambial age, hence depend on radial position in the log. This study aims to highlight how radial variations of properties and cambial age impact the mechanical behaviour of LVL panels. An analytical mechanical model has been designed to predict the modulus of elasticity of samples made from poplar LVL panels. The originality of the model resides in the integration of different data from the literature dealing with the variation in wood properties along the radius of the log. The simulation of the peeling process leads to veneers with different mechanical properties, which are randomly assembled in LVL panels. The model shows a correct mechanical behaviour prediction in comparison with experimental results of the literature, in particular with the decrease in MOE in LVL made of juvenile wood. It highlights that the bending direction and veneer thickness have no influence on the average MOE, but affect MOE dispersion. This paper proposed an adequate model to predict mechanical behaviour in the elastic domain of LVL panels based on the properties of raw wood material.