This research investigates the effects of corona plasma treatment on the mechanical properties of jute/epoxy-reinforced composites, particularly within biomedical application contexts. Plant Fibre Composites (PFCs) are attractive for medical devices and scaffolds due to their environmental friendliness, renewability, cost-effectiveness, low density, and high specific strength. However, their applications are often constrained by inferior mechanical performance arising from poor bonding between the plant fibre used as the reinforcement and the synthetic resin or polymer serving as the matrix. This study addresses the challenge of improving the weak interfacial bonding between plant fibre and synthetic resin in a 2/2 twill-weave-woven jute/epoxy composite material. The surface of the jute fibre is modified for better adhesion with the epoxy resin through plasma treatment, which exposes the jute fibre to controlled plasma energy and utilises dry air (plasma only), argon (Ar) (argon gas with plasma), and nitrogen (N₂) (nitrogen gas with plasma) at two different distances (25 mm and 35 mm) between the plasma nozzle and the fibre surface. In this context, “equilibrium” refers to the optimal combination of plasma power, treatment distance, and gas environment that collectively determines the degree of fibre surface modification. The results indicate that all plasma treatments improve the interlaminar shear strength in comparison to untreated samples, with treatments at 35 mm using N₂ gas showing a 35.4% increase in shear strength. Conversely, plasma treatment using dry air at 25 mm yields an 18.3% increase in tensile strength and a 35.7% increase in Young’s modulus. These findings highlight the importance of achieving an appropriate equilibrium among plasma intensity, treatment distance, and fibre–plasma interaction conditions to maximise the effectiveness of plasma treatment for jute/epoxy composites. This research advances sustainable innovation in biomedical materials, underscoring the potential for improved mechanical properties in environmentally friendly fibre-reinforced composites.

The current study investigated the impact of facial three-dimensional shape geometry and respirator-face interface mechanics on the fit of N95 respirators in 21 Hong Kong Chinese adults. Three-dimensional facial scanning, quantitative fit testing of four N95 respirators (3M 1860, 1870+, 9105, and 9502+), and facial dimensions extraction using Geomagic Wrap were conducted in this study. The seven fit test exercises were performed in the current investigation, while finite element analysis (FEA) was used for studying respirator-face contact mechanics in a stratified subset of 14 participants wearing 3M 1870+ geometry. Among all evaluated models, 3M 1870+ had the highest pass rate. Pearson correlation analysis showed only nominal, uncorrected associations between the fit factor and nose length (r = 0.574, p = 0.007) as well as neck circumference (r = 0.434, p = 0.050). None of the anthropometric correlations remained statistically significant after Bonferroni correction for multiple comparisons (n = 38) (adjusted alpha level = 0.00132). Threshold post hoc observations of the bitragion coronal arc, neck circumference, nose height and nose length should therefore be considered as hypothesis generation and not as screening criteria. Fit factors decreased in dynamic movements, especially when bending. FEA-predicted contact area correlated strongly with experimental fit factor (r = 0.974, 95% CI: 0.918 to 0.992, p < 0.001), thus confirming the association of simulation and fit performance measurement but not serving as independent validation of the model. These preliminary results could be helpful for future respirator fit studies and respirator design for Hong Kong Chinese adults.

Iron-based superconductors (IBSCs) represent a vital class of high-temperature superconductors. Their discovery marked a pivotal moment in condensed matter physics and materials science, offering new insights into the mechanisms of superconductivity in the presence of antiferromagnetism. However, calculating the superconducting transition temperature ( T c ) of all existing IBSCs presents an uphill struggle. In this research, a theoretical framework of electron-differential phonon coupling is tested with incorporation of electron–phonon interactions, antiferromagnetic (AFM) fluctuations, AFM spin-density waves, charge-density waves, and a small contribution from high-energy electrons below the Fermi level. This model reasonably calculates the superconducting transition temperature of the KFe ₂ Se ₂ compound under pressure, but its validity is limited to pressures up to 10 GPa. This work not only emphasizes the crucial role of exotic experimental evidence in understanding IBSCs but also demonstrates that the nature of iron-based superconductivity is significantly more complex than what the electron-differential phonon coupling model can account for at pressures exceeding 10 GPa. These findings highlight the need for further theoretical refinement to effectively capture high-pressure phenomena.