There are two simple solutions to reaction-diffusion systems with limit-cycle reaction kinetics, producing oscillatory behaviour. The reaction parameter mu gives rise to a 'space-invariant' solution, and mu versus the ratio of the diffusion coefficients gives rise to a 'time-invariant' solution. We consider the case where both solution types may be possible. This leads to a refinement of the Tu...

Waves in chemically excitable systems can refract when impinging on an interface between regions of different reaction kinetics and/or diffusion constants. Here we study this process using the thin reaction-zone limit wherein the dynamics of the system can be reduced to the tracking of the boundaries between quiescent and excited regions. We show how to derive an integrodifferential equation fo...

Biological responses often obey Weber's law, according to which the magnitude of the response depends only on the fold change in the external input. In this study, we demonstrate that a system involving a simple autocatalytic reaction shows such a response when a chemical is slowly synthesized by the reaction from a faster influx process. We also show that an autocatalytic reaction process occu...

The stability of stratified Rivlin-Ericksen fluid in porous medium in the presence of suspended particles and magnetic field has been investigated. Upon application of normal mode technique, the dispersion relation was obtained. The important results obtained in this paper include the instability of non-oscillatory modes and the stability of oscillatory modes. Also, it was found that the system...

film coating solutions containing different grades of hpmc (e5, e15 and e50) with and without polyethylene glycol (with various molecular weights) were examined by an oscillatory method, using haake cv 100 rheometer. fundamental rheological parameters (?, g? and g² ) were measured over the frequency range from 0.04 to 2 hz. the variation with frequency of the loss tangent (a ratio of viscous to...

We performed theoretical and computational studies to determine the effect of an applied mechanical strain on the dynamic behavior of heterogeneous polymer gels undergoing the oscillatory Belousov-Zhabotinsky (BZ) reaction. In these spatially heterogeneous gels, the catalyst for the reaction is localized in specific patches within the polymer network and the BZ reaction only occurs within these...

A detailed analytical and numerical analysis of a simple reaction-diffusion model of the source of non-homogeneities and arrhythmias in an originally homogeneous reaction system is pre­ sented. Solution, bifurcation and evolution diagrams are used to describe the behaviour of the model. It is shown that under certain conditions steady and/or oscillatory nonhomogeneous states are the only stable...

We introduce analog integrated circuits that imitate a typical model of a reaction diffusion system, called the Belousov-Zhabotinsky (BZ) reaction. The BZ reaction gives us many insights into developing new architectures based on a new computing paradigm such as in active wave computing. The analog unit circuit exhibits both excitatory and oscillatory behaviors with very stiff responses, as obs...