Coexistence of wave propagation and oscillation in the photosensitve Belousov-Zhabotinsky reaction on a circular route

The photosensitive Belousov-Zhabotinsky (BZ) reaction was studied on a circular ring that was drawn using computer software and then projected on a film soaked with BZ solution. It was observed that a chemical wave propagated with a constant velocity on the black ring under a bright background under initial conditions and when the background was rapidly changed to dark, coexistence of the oscillation on part of the ring and propagation of the chemical wave on the other part was observed.