This study concerns a numerical investigation of a magnetohydrodynamic (MHD) natural convection of a Fe₃O₄–water nanofluid filled within a round diagonal corner square cavity. The cavity was subjected to imposed temperatures (hot and cold walls) and one magnetic source. The nanofluid flow and heat transfer problem was mathematically modeled and its dimensionless problem was established. The finite element method was implemented in order to solve the MHD problem. The effects of the Rayleigh number, Hartmann number and round corner radius on the nanofluid flow (streamlines and velocity magnitude) and heat transfer (isotherms and temperature distribution) were evaluated. Heat transfer was assessed when the convection or the conduction dominates with regard to the nature of the flow.

The study investigates the physical properties, strength, and flexibility of the jute/kenaf/glass reinforced composite. The composite is infused with equal quantities of silicon dioxide (SiO₂), nanographene, and multi‐walled carbon nanotubes (MWCNTs) at a concentration of 5 wt%, as specified by ASTM standards. The composite was created using a manual lay‐up approach followed by compression molding, using a unique 10‐layer fiber structure. The S4 (5%) composite specimen increased its tensile strength (TS) from 91 to 101 MPa, tensile modulus (TM) from 7.286 GPa to 10.286 GPa, interlaminar shear strength (ILSS) from 9.39 to 19.71 MPa, and glass‐transition temperature (Tg) from 70°C to 85°C. The results show that the 5 wt% MWCNTs have significantly higher TS, TM, ILSS, and Tg than the unfilled composite and SiO₂, nanographene, with increases of 5%, 2%, and 10%, respectively. Incorporating MWCNT nanofillers into composites significantly enhances their mechanical and dynamic characteristics when compared to composites without fillers. The study's findings show that adding MWCNTs to the matrix significantly improves performance when compared to the composite without any fillers. Scanning electron microscopy images reveal the underlying reasons of failure in composites, such as layer separation, material fissures, fiber extraction, and fiber breakage. The incorporation of 5 wt% MWCNTs into the jute/kenaf/glass hybrid composite matrix significantly enhances mechanical and dynamic properties compared to composites without fillers.