The time courses of the entropy production rate (1, 2, and ) in Figure show that they become constant after the lapse of a sufficiently long time in both cases (a) and (b), as previously mentioned. Achieving constant 1, 2, and  means achieving constant reaction and diffusion rates, i.e. the achievement of a steady state. Essentially the same results were obtained for 1, 2, and  under other reaction conditions and for ORNs having structures that differ from that in Figure .