This is done by me in First Part of Website by invoking dynamical systems theory, and with it the concept of dynamical law as the Essence of the thing that is generated by the corresponding dynamical system.
All what is replaceable under the constancy of the dynamical law, is per accidens with respect to this dynamical law (Essence), and allows in this context to be taken as accident. The substance s.str. is this Essence (dynamical law).