Research Articles

Effects of a boron-phenol-based flame retardant were evaluated relative to the combustion performance and mechanical properties of structural plywood manufactured from two domestic softwood species: larch (Larix kaempferi) and Korean pine (Pinus densiflora). The flame retardant was applied using a standardized vacuum-pressure impregnation process, and the retention level, combustion resistance, and structural integrity of the treated specimens were determined. The results showed that the treated specimens met the Korean standard (KS F 3113) requirements for bending strength, modulus of elasticity, and water-resistant tensile-shear strength. Larch plywood exhibited modest changes in combustion and mechanical performance, whereas Korean pine showed significant improvements in flame retardancy, including longer ignition time, lower peak heat release rate, and reduced char length and area owing to the higher flame-retardant retention achieved with Korean pine. Furthermore, flame retardant impregnation did not affect adhesive bonding in either species. This study demonstrates that boron–phenol-based flame retardants can effectively enhance fire resistance in structural plywood without compromising its mechanical performance, thus supporting their applicability in manufacturing flame-retardant wood-based construction materials.

As more people use chemical preservatives and antibiotics, there is a growing need for safe, natural alternatives. It was posited that black seed oil (Nigella sativa) (BSO) and its nanoemulsion (BSO-NE) might exhibit significant antibacterial efficacy against clinically pertinent pathogens. To verify this, BSO-NE was synthesized utilizing the emulsion inversion point (EIP) technique, yielding stable nanoscale oil-in-water droplets, which were validated by Transmission Electron Microscopy (TEM) and Dynamic Light Scattering (DLS). The antimicrobial activities of BSO and BSO-NE were tested against a group of Gram-positive and Gram-negative bacteria using CFU-reduction assays and agar well diffusion. BSO strongly inhibited the growth of Staphylococcus epidermidis (96.6% CFU reduction), while BSO-NE showed varying but still significant activity against the strains that were tested. To investigate the mechanism, molecular docking of thymoquinone and thymohydroquinone with ATPase demonstrated greater binding affinities compared to the reference ligand, corroborating the experimental results. These results show that BSO could be a natural antimicrobial agent and that improving NE formulations could make them work even better. The research highlights the potential of essential-oil-based nanostructures as scalable options for pharmaceutical, biomedical, and food preservation applications.

Fly ash can enhance soil structure, nutrient availability, and water retention, making it a promising soil conditioner for agricultural applications. The growth and yield performance of Napier grass (Pennisetum purpureum) cultivar Pak Chong 1 was evaluated under different soil treatments. The control treatment consisted of 313 kg/ha NPK (Nitrogen, Phosphorus, and Potassium), 1,563 kg/ha dolomite, and 6,250 kg/ha manure, while fly ash was applied at levels of 1,563, 3,125, 6,250, and 12,500 kg/ha. Growth parameters such as plant height, number of tillers per clump, leaf-to-stem ratio, dry-to-fresh weight ratio, and heavy metal accumulation were examined. The fly ash significantly increased plant height, tiller number, and biomass yield compared to the control in most cutting cycles. However, the control occasionally exhibited higher leaf-to-stem ratios, suggesting that fly ash promotes stem growth more than leaf expansion, indicating an advantage for biomass production. Notably, the 3,125 kg/ha fly ash treatment resulted in considerable lead accumulation in leaves; however, this Pb originated from the native soil, not the fly ash, which had non-detectable levels. Higher fly ash levels (e.g., 12,500 kg/ha) effectively reduced Pb uptake, indicating the need for dosage optimization to ensure heavy metal immobilization.

This study aimed to investigate the effects of an expanded polystyrene (EPS) layer and varying precast concrete thickness on the stiffness and acoustic performance of cross-laminated timber (CLT) slabs. Six different concrete thicknesses and EPS layers were applied to larch and pine CLT slabs for testing. Airborne sound transmission loss (D_w) was measured using speakers, light impact sound (L_nT,w) using a tapping machine, and heavy impact sound (L_iA,Fmax) using rubber balls, in accordance with KS F ISO717-2. The results indicated that the EPS layer significantly improved light impact sound insulation (by 8 dB) and airborne noise insulation (by 5 dB), but had a minimal effect on heavy impact sound (0.5 dB). Both stiffness and sound insulation increased with concrete thickness, although improvement plateaued beyond 100 mm for larch CLT and 150 mm for pine CLT. The flexural and impact stiffness of larch CLT slabs were 24.3% and 19.2% higher than those of pine CLT slabs, respectively. Moreover, impact stiffness demonstrated a stronger correlation with acoustic performance than the previously established relationship with area density.

Molded pulp packaging is rapidly growing as a sustainable packaging solution, but cost remains one of the biggest challenges. This study systematically investigates the potential use of mineral fillers as a cost-reduction strategy for molded pulp, using a design-of-experiments (DOE)-based approach. Laboratory-scale samples were produced with two ground calcium carbonate (GCC) fillers of different particle sizes at increasing dosages, and pore structure, mechanical properties, and dewatering/drying efficiency across stages of the molded-pulp process were assessed. With increasing filler dosage, mechanical properties decreased in three steps: slow initially, a steep mid-stage drop, then a slower final decline. The pore structure results correlated with this three-step change. The optimal filler-dosage range was determined from this three-step behavior and defined as the dosage corresponding to 80% of the maximum mechanical property reduction rate. GCC fillers improved the dewatering capability of the pulp suspension; however, this did not translate into improved dewatering efficiency at later stages. Future research is suggested to enable the successful application of mineral fillers in molded pulp products.

This study was conducted to examine how sustainability-oriented (“green”) claims influence consumer responses to bio-based paper and packaging products in digital marketplaces. A total of 611 verified consumer reviews were analyzed, including 230 from Amazon and 381 from Trendyol, covering the period between 2020 and 2025. Through digital content and sentiment analysis, the relationship between eco-communication and perceived value, satisfaction, and trust was explored. A cross-platform analytical pipeline was developed to ensure transparency and reproducibility. Daily review frequencies were aggregated into seven-day rolling averages so that temporal patterns such as enthusiasm bursts and stabilization trends could be identified. It was observed that consumer sentiment was predominantly positive but asymmetrically distributed. Explicit “green” claims such as biodegradable, recyclable, and eco-friendly were found to stimulate higher engagement while also inducing greater polarization, resulting in a characteristic J-shaped rating distribution. Broader variance in Amazon reviews was attributed to the platform’s diverse cultural composition, whereas Trendyol reviews exhibited faster stabilization, indicating stronger normative coherence and trust in localized sustainability messages. Overall, these findings suggest that sustainability has shifted from an optional feature to a baseline expectation in digital consumption. “Green” attributes are now perceived as authenticity and reliability cues that merge ethical commitment with functional quality.

Soils contaminated with heavy metals, such as arsenic (As), pose significant environmental risks and can cause serious ecological and health-related damage. Biological methods, such as bioleaching (organic acids), biosorption (lignocellulosic materials, microbial biofilms), and bioaccumulation (microbial biofilms), have shown potential for remediating of heavy metal pollution sites. However, research optimizing the bio-based solutions remains limited. This study aimed to optimize As leaching from two abandoned mine soils using oxalic acid (OA). Response surface methodology (RSM) with a second-order central composite design (CCD) was employed to determine the optimal conditions, focusing on OA concentration and soil weight. Additionally, OA production by the brown-rot fungus Antrodia albida was monitored, revealing significant synthesis under low pH conditions, with peak production observed on the eighth day of incubation. The bioleaching efficiency of fungal OA was compared with commercial OA, showing comparable As extraction rates exceeding 95% in both soil types. However, the extraction efficiency for other heavy metals varied: fungal OA was more effective for cadmium, nickel, and lead, whereas commercial OA demonstrated higher efficiency for chromium, copper, and zinc. These findings underscore the potential of fungal OA as a sustainable alternative for remediating soils contaminated with heavy metals, particularly in low-pH environments.

This study investigated the effects of fire-retardant coating treatments on the combustion resistance of Scots pine wood (Pinus sylvestris L.) impregnated with various chemicals. Borax, boric acid, zinc chloride, sodium silicate, and ammonium sulfate were used as impregnation materials. Fire-retardant paint and nano-enabled fire-retardant varnish were applied as coating materials. Combustion tests were conducted using a computer-controlled apparatus developed in accordance with the ASTM E69-22 (2022) standard. During combustion, mass loss and maximum temperature values were recorded every 30 s. As a result, impregnation applied to the Scots pine wood material was observed to reduce the mass loss, including 31% borax, 37% boric acid, 43% zinc chloride, 35% ammonium sulfate, and 31% sodium silicate. It was observed that coating formulation to the Scots pine wood decreased mass loss 59% with nano varnish and 71% with fire-retardant paint.

Strip-like laminations are wood lamellae formed by face-gluing small wood segments to reduce the effect of natural defects and enable the use of lower-grade timber. This technique offers a promising solution for transforming low-grade wood into solid products. However, its impact on full-scale structural components such as glulam beams has yet to be thoroughly assessed. This study investigated how external layers made of strip-like laminations affected glulam’s bending properties and bonding performance. Grade No. 2 yellow birch (Betula alleghaniensis Britt.) was bonded with one-component polyurethane to fabricate six-layer glulam beams, with strip-like laminations placed on the outer layers. Mechanical testing, including four-point bending, block shear, and delamination, was conducted in accordance with North American standards. Results showed a one-third reduction in the variability of modulus of rupture (MOR), while maintaining comparable performance to traditional glulam configurations. Although apparent modulus of elasticity (MOE_app) was slightly lower and similar to beams containing visual defects, block-shear strength exceeded 90% approval. Some cases of delamination above 10% highlight opportunities for process refinement. These findings demonstrate the potential of strip-like laminations for improving material utilization and provide valuable insights for optimizing manufacturing strategies.

Laboratory tests were conducted on innovatively designed corrugated board packaging under random vertical vibrations. The innovative designs had reinforced critical corner zones and lid–base interfaces through geometry modifications that increased double-wall regions. A total of 25 packaging variants, differentiated in structure, layer configuration (three-layer and five-layer boards), and surface finish (with and without coatings) were evaluated. The experimental study included box compression tests (BCT) and random vibration tests according to international standards (ISO 12048:1994 and ISO 13355:2016), simulating storage and transportation conditions. All packages were assessed before and after random vibration tests to determine the influence of dynamic loads on structural load-bearing capacity. Unlike previous studies limited to static testing, this work evaluated combined vibration and compression effects under standardized dynamic loading conditions for packaging with relatively low probability of being dropped. Furthermore, it was shown that the innovative design of corrugated board transport packaging presents higher static load capacity after random vibration testing in terms of column compression strength, indicating that no reduction in box strength was observed during simplified transport simulation under pure one-direction dynamic loading. The findings contribute to the optimization of high-durability packaging solutions tailored for the growing demands  of complex logistics chains.