Volume 20 Issue 2

The applications of wood are limited by its hygroscopicity and resulting dimensional changes, which reduce its service life for outdoor conditions. Modification methods develop the usages of wood-based products by altering the structure. This study compared the effect of oil heat treatment (OHT) with raw (SO) and epoxidized soybean oil (ESO) at different temperatures relative to the practical properties of eucalyptus wood. Fourier transform infrared spectra confirmed hemicellulose degradation with increasing temperatures of ESO-treated specimens. With increasing temperature, ESO darkened the specimens compared to SO. Thermal modification at the highest temperature in ESO resulted in a weight loss of modified specimens and the lowest density, with more hydrophobicity and dimensional stability compared to the SO-modified specimens. Based on bending data, unlike modulus of elasticity (MOE), modulus of rupture (MOR) did not show a statistical difference between the two types of oils, except at 150 °C. At 200 °C, the specimens modified with ESO exhibited lower hardness than SO. The impact resistance of 150 and 175 °C/ESO modified specimens was higher than SO specimens. In summary, functionalized vegetable oil significantly improved physical characteristics compared to SO, with obvious improvement in impact strength at 150 °C.

With the recovery of the economy and growth of living standards, the demand for wood furniture is increasing, leading to a focus on wood quality and market value. Mid-infrared (MIR) spectroscopy, which characterizes molecular vibrations, is well-suited for wood classification due to its ability to identify molecular structures. This study utilizes a Fourier Transform Infrared (FTIR) spectrometer to classify 31 wood species based on their commercial categories. While the basic composition of wood species is similar, spectral data are overall close, necessitating a robust approach for accurate identification. To address this, a two-dimensional transformation of the spectral data is performed, to convert wavenumber sequence and state transition probabilities (quantized intensity levels) of spectra into a matrix, followed by deep learning classification using the transformed data. This resulted in the development of the MTF-SKNet model, achieving a classification accuracy of 93% for wood species. The model demonstrated strong generalization performance, reaching 96% accuracy in classifying the rosewood category of woods.

The scientific community is actively developing innovative nanomaterials with broad-spectrum antimicrobial properties. In this study, moringa gum-derived polymeric carbon dots (MGCDs) were synthesized via a rapid and eco-friendly microwave irradiation technique using aqueous moringa gum as the precursor. The resulting MGCDs exhibited strong green fluorescence under UV light, with a UV-Vis absorption peak at ~290 nm and excitation-dependent fluorescence at 360 nm. They demonstrated significant antioxidant activity, achieving 87% DPPH scavenging efficiency at 0.9 mg/mL, comparable to ascorbic acid. Zeta potential analysis confirmed high colloidal stability, with values of 29 ± 0.9 mV (DI water), 30 ± 0.8 mV (SBB), 28 ± 9 mV (PBS), and 23 ± 0.8 mV (DMEM). Hydrodynamic sizes ranged from 86 ± 3 nm to 135 ± 4 nm, indicating solvent-dependent dispersion. TGA showed high thermal stability, while XRD confirmed an amorphous carbon structure with a broad peak at 22°. MGCDs demonstrated the antibacterial activity against Staphylococcus aureus and Bacillus subtilis, resulting in inhibition zones of 17.4 ± 0.8 mm and 15.2 ± 0.6 mm, respectively, at 40 mg/mL. Their multifunctionality, simple synthesis, and cost-effectiveness highlight their potential in bioimaging, antimicrobial applications, and fluorescent materials.

Nests made by the Najdian termite, Microtermes najdensis, were studied. The climate, soil, intact wood, and nest wall were investigated. The entryways of the termite nests were located at the southwest direction, which promotes better ventilation. The internal temperature (IT) was warmer than the outer temperature (OT) during cold days, while it was cooler than the hottest OT on hot days, and vice versa. The IT had more constancy than the OT. Moreover, the IT trended toward the upper OT’s limit, indicating that termites prefer the hotter atmospheres. Lignin is the prominent tracer of the organic matter used as a binder for the nest wall due to its gluability and resistance to enzymatic or fungal degradation. Features resembling microcrystalline cellulose (MCC) and nanocrystalline cellulose (NCC) were discovered for the first time in the nest mortar reinforcing Klason lignin. Their presence was attributed to enzymatic hydrolysis by the termites and/or their accompanying fungal community. The gross heat of combustion (GHCs) of the intact wood and nest wall were studied. Finally, a theory illustrating the fabrication of termite nests was postulated.

Single-layer particleboards were fabricated from rice straw bonded with chitosan. The rice straw was pre-treated by steam explosion to reduce the extractives and ash contents. The obtained pulp was analyzed for chemical composition, which indicated that the steam explosion pretreatment effectively decreased the extractives and ash contents. The effects of steam explosion pretreatment and chitosan contents on mechanical properties and dimensional stability of rice straw particleboards were explored. The mechanical properties and dimensional stability of particleboards made of steam exploded rice straw showed significant improvement. Addition of chitosan increased the mechanical properties and dimensional stability of particleboards. The mechanical properties and dimensional stability of particleboards improved with the increase of chitosan content.

Zoysiagrass (Zoysia japonica Steud.) is a widely planted warm-season turfgrass; however, its long winter dormancy limits broader adoption, especially in transitional and subtropical regions. Glycine betaine (GB) is known to mitigate cold stress in controlled environments, but its potential to improve chilling tolerance of zoysiagrass as measured by winter color retention under field conditions remains unclear. This study investigated the effects of fall-applied GB and nitrogen (N) on winter color and spring green-up of zoysiagrass under field conditions in a Mediterranean climate in Türkiye. Conducted from 2018 to 2020 in Antalya, the experiment tested different application levels of N (0, 2.5, and 5 g/m²) and GB (0, 0.8, and 1.6 g/m²). N applications significantly improved key parameters, such as winter color retention, turf quality, chlorophyll content, and spring green-up. The highest N (5 g/m²) extended the green period from 7 to 10 months by delaying dormancy. In contrast, GB treatments had no significant effects. Although GB showed limited effectiveness, its evaluation under field conditions provides valuable insight into its practical relevance for warm-season turf management. The limited effect may be related to application amount and application timing. Further research with a broader range of GB application rates may help uncover its full potential under chilling stress conditions.

Advancements in cross-laminated timber (CLT) applications have introduced the potential to use it as an alternative to reinforced concrete in basement construction. Understanding dimensional stability is crucial to ensure the reliability and safety of CLT in below-grade environments. An experimental CLT basement was constructed in Edmonton, Canada, and monitored over a period of two years. Field measurements were analyzed to estimate the dimensional changes and understand the deformation modes of the CLT panels resulting from changes in boundary conditions. A supporting laboratory experiment with specimens made from single pieces of dimensional lumber was conducted to establish a basis for comparing field-measured dimensional changes in CLT and determining the effects of cross-lamination on swelling and shrinkage coefficients. The average swelling and shrinkage coefficients calculated for CLT were approximately twice as large as the longitudinal and 20 times smaller than the transverse coefficients obtained from the laboratory experiments on solid wood specimens, indicating the influence of cross-lamination on these coefficients. Four deformation modes were identified based on measurements from field-installed strain gauges. The study provides new insights into the impact of water ingress on the swelling coefficient and the effects of different drying conditions on the shrinkage coefficients of CLT.

Curcuma caesia Roxb. (Zingiberaceae) is one of the endangered species in the genus Curcuma that possesses numerous beneficial bioactive compounds that are responsible for various pharmacological properties including anti-cancer, anti-asthmatic, anti-diabetic, and others. In the past few years, the number of C. caesia plants was reported to have drastically decreased due to over-harvesting activity. To conserve this species, plant tissue culture method was used as a propagation tool for the mass production of C. caesia plantlets. Hence, this study aimed to optimize the extraction of phenolics content and antioxidant activities using response surface methodology. In this study, central composite design (CCD) was used to investigate the effects of three independent variables, namely solvent-solid ratio (mL/g), methanol concentration (%), and extraction temperature (°C), on phenolics content and antioxidant activities. Based on the results, the optimal extraction condition was achieved using 54.02 mL/g solvent-solid ratio, 70% methanol concentration, and 70 °C of extraction temperature.

Southern pine samples were vacuum-pressure impregnated with nano-SiO₂ with Nano-SiO₂ based on different specific surface areas (60, 150, 200, 380m².g^-1) and impregnated with alkaline copper quat type D (ACQ-D) preservatives or ACQ-D preservatives modified with emulsified wax. The treated wood was exposed outdoors for one year. The effects of emulsified wax and different conditions of nano-SiO₂ on the color change, wettability, and thermal stability of the treated wood were evaluated by colorimeter, contact angle tester, and thermogravimetry (TG). The results showed that nano-SiO₂ modification was helpful to keep the surface color stable for ACQ-D treated wood, while the effect of emulsified wax and the specific area of nano-SiO₂ on the color stability was slight. The static contact angles were increased after outdoor exposure with nano-SiO₂ and/or emulsified wax because of the reduction of the free hydroxyl groups, especially for nano-SiO₂ with smaller specific surface area. The thermal stability of ACQ-D treated wood could be increased to different degrees depending on the type of nano-SiO₂ and whether emulsified wax were present in the treated wood, although the emulsified wax only played an auxiliary effect on the thermal stability of the treated wood.

This study addressed the efficiency of different biochars in Cd immobilization in soil. An acidic sandy loam paddy contaminated with Cd was selected for the field trial, which was continued for three rice-growing seasons. Rice straw biochar (BR), wheat straw biochar (BW), and maize straw biochar (BM) were pyrolysed as pellets at 450 °C and applied at 0 t/ha (BC0), 10 t/ha (BR1/BW1/BM1), and 20 t/ha (BR2/BW2/BM2). Compared to BC0, BR and BW were more effective in decreasing Cd accumulation in rice grains, and BR2 achieved the highest reduction, averaging 43.4% over three rice seasons. The Cd contents in rice roots with BR2 treatment decreased by 15.2 to 55.3% compared with BC0. The bioconcentration factors for grains (BCF_Grain), shoots (BCF_Shoot), and (BCF_Root) of BR2 treatment were averagely decreased by 53.3%, 27.4%, and 19.0% over BC0, respectively. There was a negative correlation between soil CaCl₂-Cd and soil pH. FTIR analysis demonstrated that Cd complexed with SiO₂ on aged BR2 particles. During the natural aging process, BR2 significantly and sustainably inhibited rice uptake Cd through co-deposition. Therefore, the BR was judged to be an effective soil amendment with high Si content and alkalinity for Cd immobilization in paddy soil.