Effects of density-affecting scalar on the onset of chaos in a simplified model of thermal convection: a nonlinear dynamical perspectiveSungju Moon, Jong-Jin Baik, Jaemyeong Mango Seo and Beom-Soon HanEur. Phys. J. Plus, 136 1 (2021) 92DOI: https://doi.org/10.1140/epjp/s13360-020-01047-7