BZ System Research Articles

From quasiperiodicity to chaos in the Belousov–Zhabotinskii reaction. II. Modeling and theory

We discuss the quasiperiodic behavior experimentally observed in the Belousov–Zhabotinskii reaction as the result of the interaction of two elementary instabilities, namely the Hopf bifurcation at the origin of the oscillating nature of this reaction and the hysteresis bifurcation which accounts for the phenomenom of bistability. We use a normal form approach to understand the evolution of the dynamics when the BZ system is moved away from the local situation where both these instabilities are competing. We first discuss the transition to chaos which comes with the breaking up of the underlying torus into a fractal object. Then we emphasize that nonlocally such a two-frequency dynamics manifests through alternating periodic–chaotic sequences which look very much like the sequences observed in bench experiments. We propose a seven-variable Oregonator type model which not only accounts for these sequences but also for those which involve only one fundamental frequency as observed in the 1980 Texas experiment. We refer to the dynamical system theory to definitively establish the existence of deterministic chaos in both of these sequences. We conclude with the very promising perspective of using a normal form approach to reduce the evolution equations to their simplest form by selecting the relevant instabilities which control the dynamics of the BZ reaction in the regions of parameter space explored so far.

On the alcohol inhibition of the reacting BZ system

The effect of aliphatic alcohols on the reacting BZ system has been studied and the mechanism of alcohol inhibition interpreted.

Formation of Carbon Dioxide in the Belousov-Zhabotinsky-Reaction

Abstract The rate of formation of CO2 in the BZ system is measured and compared to the predictions of the Field-Körös-Noyes (FKN)-theory. The experimental rate is found to be larger than the theoretical rate by a factor of about 100. This discrepancy cannot be easily explained without severe changes in the FKN model. Moreover, improved rate constants of the most important organic reactions in the BZ system are given.

Spectrophotometric study of the BrO 3 − /Ce4+/1,3-cyclohexanedione oscillating system

The modified Belousov-Zhabotinskii oscillatory system with 1,3-cyclohexanedione as substrate is described. Oscillations with a decreasing amplitude take place also if the solution is not stirred. Mechanical stirring of the BZ system does not influence the induction period and the period of the first oscillation at various temperatures, however it results in a smoother course of the oscillations.

The classification of lighting fittings and installations

There is a general need for a system of classifying lighting fittings as a means of comparing their performance. Systems are based on the relative quantities of luminous flux emitted by fittings in the upper and lower hemispheres, but must not be too complicated for practical use. The BZ system extended the basis of classification and has become widely used since its introduction in 1961. Experience with the system has revealed certain deficiencies which are examined; suggested modifications are considered. The classification system proposed by CIE Committee E-3.1.1.1 is being studied.