The effect of exothermic reaction associated with activation energy in hydromagnetic convection heat transfer flow of Water based (MoS2 – SiO2 / H2O) hybrid nanofluid through a cylindrical annulus with variable viscosity: Darcy-forchheimer model. IJBB. 2026;63(4):453-468. doi:10.56042/ijbb.v63i4.22123