Research Articles

Iron oxide (FeONP) and copper oxide (CuONP) nanoparticles were synthesized using the leaf extract of Conocarpus lancifolius. Their activity against two phytopathogenic fungi, Alternaria solani and Fusarium solani, was investigated. The colonies’ diameter and morphological changes in the fungal hyphae and conidia treated with nanoparticles were examined using scanning electron microscopy (SEM). CuONPs showed oval particles with a wide particle size distribution of ~57 nm in length and ~28 nm in width. FeONPs showed elliptical disks with a wider particle size distribution of 32 to 39 nm in length and 5 to 14 nm in width. Both types of nanoparticles exhibited significant antifungal activity against A. solani and F. solani. CuONPs inhibited A. solani growth by 88.9% to 91.1% in terms of the fungal colony diameter after 12 days of incubation. They completely inhibited the growth of F. solani. In contrast, FeONPs reduced the growth of A. solani from 68.9% to 73.3%. The SEM images suggest that CuONPs and FeONPs damaged and distorted the fungus structure, consequently limiting and inhibiting fungal growth. Therefore, the green synthesized nanoparticles could be used as antifungal candidates to protect plants against phytopathogenic fungi.

In order to develop high-performance supercapacitor electrode materials, a two-step method of hydrothermal in-situ synthesis and high-temperature activated pore creation was used to realize the highly dispersed loading of nickel oxide nanoparticles (NiO) on mango kernel-based activated carbon (AC) with a high specific surface area for the preparation of NiO/AC composites. Electrochemical tests showed that the NiO/AC achieved a specific capacitance of 226.5 F g^-1 at a current density of 0.2 A g^-1, demonstrating excellent multiplicative performance and cycling stability (95.8% capacitance retention after 10,000 charge/discharge cycles). This performance stems from the stabilized multilayered pore structure that reduces the particle size of NiO and builds fast ion/electron transport channels to realize the dual advantages of double layer capacitance and pseudocapacitance. The present synthesis strategy is universal (compatible with multifunctional porous carbon precursors and metal oxides) and can provide new ideas for the design of high-performance supercapacitor electrodes.

Ancient Chinese covered bridges are attracting increased attention due to their architectural appearance and manufacturing technique. In this study, an ancient single-arch covered bridge, Yinjia bridge, in Peach Blossom Spring in China has been investigated, mainly in the field of its cultural background, art aesthetics, and mechanical behavior. The methods of field measurement and finite element analysis were combined. First, the structural dimensions and construction of Yinjia bridge are introduced. Then, the historical origin and cultural connotation, the bridge corridor and decoration are considered, and the Chinese culture reflected behind the bridge design are investigated. A finite element model was built to study the mechanical behavior of the bridge. The numerical results indicate that the maximum vertical deflection of 4.32 mm is under but close to the limit of L/600, while no horizontal deflection exists at the foot of the arch crown. The maximum and minimum normal stress of 0.04 MPa and -0.12 MPa in components of bridge corridor are much less than the ultimate values of wood. The maximum compressive stress of 0.05 MPa of the bridge arch is within the limit value of the ultimate compressive strength of stone. This means that the structural safety performance of this ancient bridge is acceptable, and indicates that no significant structural damage has been found yet in the Yuxian bridge.

A bio-based reinforcement strategy was studied as a means to overcome the inherent weaknesses of thermoplastic cassava starch (TPCS), namely its low mechanical strength and high susceptibility to moisture. Candelilla wax, a natural hydrophobic additive, was incorporated into TPCS at different loadings (0, 2.5, 5, 7.5, and 10 wt %) and processed via hot-press compression moulding. The fabricated composites were characterised to examine the effects of wax addition on their mechanical, thermal, and moisture-resistance performance. Mechanical tests (tensile, flexural, and impact), with scanning electron microscopy (SEM), thermogravimetric analysis (TGA). The incorporation of candelilla wax notably improved the material’s performance, particularly at 5 wt%, where tensile strength and modulus increased 77.4% and 615%, respectively. Flexural and impact strength also increased, indicating enhanced toughness. The SEM micrographs showed rougher fracture surfaces with increasing wax, while Fourier transform infrared spectroscopy (FT-IR) confirmed intermolecular hydrogen bonding between starch and wax. Improved thermal stability and reduced water sensitivity were also observed, with the 10 wt % wax composites exhibiting the lowest moisture absorption, solubility, and swelling. Overall, candelilla wax proved effective in strengthening TPCS both structurally and functionally, highlighting its potential for sustainable biodegradable materials in moisture-sensitive applications.

Ultrasonic-assisted extraction was employed to obtain soluble dietary fiber (SDF) from defatted rice bran. Response surface methodology (RSM) was conducted to investigate and optimize the effects of solid-liquid ratio, amplitude, and ultrasonic time on the extraction. The optimal conditions were determined as an ultrasonic time of 19 min, an amplitude of 20%, and a solid-to-liquid ratio of 1:14 (g/mL), achieving an actual extraction yield of 14.3%. Under these conditions, the SDF exhibited enhanced water-holding (3.21±0.03 g/g), oil-holding (1.78±0.02 g/g), swelling (2.03±0.02 mL/g), solubility (0.82±0.02 g/g), glucose adsorption capacity, and cholesterol adsorption capacity properties compared to untreated rice bran dietary fiber, facilitating its processing and utilization. Laser particle size analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction revealed that ultrasonic treatment caused the SDF to expose more chemical groups, strengthen intermolecular hydrogen bonds, and transform into a rough, porous structure with numerous wrinkles. Overall, ultrasound was shown to effectively improve the physicochemical and functional properties of defatted rice bran SDF, offering a theoretical foundation for its extraction and application.

The loss factor of wood material is frequency related, which directly affects the calculation method of dynamic responses for wood structures. In this paper, the relationship between loss factor and damping coefficient was determined based on equal dissipated energy. Combined with the time-domain and frequency-domain methods, a modal superposition method was proposed to calculate the dynamic response of wood structures. Compared with the frequency-domain method, the proposed method can additionally consider the transient vibration responses of wood structures. Compared with the equivalent time-domain method based on constant loss factor, the proposed method can additionally consider the influence of frequency related loss factor. The proposed method should be preferred to calculate dynamic responses of wood structures.

The block shear bonding performance was studied for glued laminated timber (glulam) manufactured from laran, a Malaysian plantation hardwood, under four treatment conditions designed to simulate service environments. Forty block shear specimens were tested to determine shear strength and wood failure percentage (WFP). The conditions comprised (a) dry (control, equilibrium laboratory climate), (b) water-soak (immersion in 20 ± 3 °C water for 24 h), (c) boiling Immersion (100 °C for 6 h followed by cooling), and (d) boil–dry–boil cycle (repeated hot–wet and drying exposure). Each specimen (50 × 50 × 50 mm³) was loaded in shear using a universal testing machine. Results revealed a progressive reduction in both shear strength and WFP with increasing treatment severity. Dry samples exhibited the highest bonding performance, while specimens subjected to the Boil–Dry–Boil Cycle showed the greatest deterioration. These findings demonstrate the sensitivity of laran glulam to moisture and thermal cycling, provide baseline data for adhesive bond durability across service classes, and offer valuable insights for improving treatment strategies, product design, and the long-term structural reliability of glulam in tropical construction contexts.

The feasibility of improving medium-density fiberboard (MDF) for structural applications was addressed by improving its mechanical and dimensional properties through modifications in resin formulation and board density. Melamine-urea-formaldehyde (MUF) resin was used as the adhesive, with three melamine substitution levels (25%, 27%, and 30%), resin contents ranging from 18% to 26% (based on oven-dry fiber weight), and target densities of 790, 820, and 850 kg/m³. The MDF bonded with MUF containing 30% melamine showed higher modulus of rupture (MOR) and water resistance indicated by lower thickness swelling (TS) and water absorption (WA) than those with 25% melamine. Increasing the resin content improved MOR and significantly reduced TS, with optimal performance at 26% resin content. Higher density positively affected mechanical properties and dimensional stability. The MDF with a density of 851 kg/m³ showed the best results in both MOR and WA, confirming its suitability for structural applications. The optimal formulation of 30% melamine content, 26% resin content, 1% hardener, 1% wax, and a density of 851 kg/m³ met the performance criteria for structural MDF. Notably, under these optimal conditions, the formaldehyde emission was 0.48 mg/L, satisfying stringent environmental standards.