Experimental Investigation of the Dynamical Modes of Four Pulse‐Coupled Chemical Micro‐Oscillators

Abstract

We present an experimental system of four identical microreactors (MRs) in which the photosensitive oscillatory Belousov‐Zhabotinsky (BZ) reaction occurs. The inhibitory coupling of these BZ MRs is organized via pulses of light coming to each MR from a computer projector. These pulses are induced by spike(s) in other MR(s) of the same network. Time delay between the spike in one BZ MR and the pulsed perturbation of the other BZ MR(s), the amplitude of light pulses, their duration, and the connectivity of the MRs are controlled by the LabVIEW software. Recording the dynamics of the BZ reaction in the MRs via a microscope equipped with a CCD camera, we observe all the main dynamical modes of our network of MRs, which are the IP (in‐phase), AP (anti‐phase), W (walk), and WR (walk reverse) for the unidirectional coupling, and the IP, two‐cluster, three‐cluster, and splay modes for the all‐to‐all coupling. Our software detects all the modes of the network automatically and makes it possible to switch between them on demand using a few special “switching” pulses. As the result of the present work, the experimental implementation of the adaptive behaviour of the pulse‐coupled chemical micro‐oscillator networks becomes available.

Experimental verification of an opto-chemical “neurocomputer”

“…2. It is analogous to similar setups developed earlier by us 24 or by other groups. [27][28][29] Block scheme of the experimental setup.…”

“…To find the phases j (k) sw , we use phase response curves (PRCs) for the CPG oscillators and our previous data on controllable switching between CPG modes. 23,24,26 These data allow us to calculate approximate phases and phase shifts Dj k needed to fulfill the transition. Internal pulses that couple neighboring CPG oscillators largely affect the needed phase shifts Dj k making them smaller or larger.…”

“…The circuits of the electronic units built with the aid of LabVIEW software 31 are presented elsewhere. 24 These units imitate actions of the real (made of excitable BZ cells) R, R A , and DM units. The cells of these units work as logical elements ''AND''.…”

“…23 The CPG unit composed of micro-oscillators has been implemented as well. 24 The functioning of the reader R that should differentiate and recognize different CPG modes was investigated computationally 25 and experimentally using an electronic R-unit constructed with the aid of LabVIEW software. 24 In the present work, we bring together all the units of the CN and demonstrate experimentally that the CN really works, and works in accordance with our theoretical expectations.…”

Controlling Chemical Waves by Transforming Transient Mass Transfer

“…A typical example of broad concern is chemical waves. [ 15–23 ] In simple terms, chemical waves, driven far from equilibrium, feature concentration profiles with spatiotemporal variations, which are completely transient problems. Unfortunately, transient mass transfer generally does not have the property of form‐invariance under coordinate transformations, so the existing transformation theory is not applicable.…”