On-Uma Kheowan

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The dynamics of rigidly rotating spiral waves in a reaction layer with light-dependent excitability is studied by numerical integration of a reaction-diffusion equation system with a feedback control. The feedback signal is derived from sensory domains with different geometries by introducing an algorithm that computes the illumination intensity to be(More)
We characterize the spatiotemporal evolution of a photosensitive Belousov-Zhabotinsky medium that is made up of coupled oscillatory cells with randomly distributed frequencies. The medium evolves from an initial state of multiple wave sources to a synchronized state governed by a single wave source. The synchronization occurs via a competition between the(More)
During an experimental study of the resonance attractor for spiral waves in the light-sensitive Belousov-Zhabotinsky reaction, strong deviations of the attractor trajectories from circular orbits are observed if the time delay in the feedback loop becomes relatively long. A theory is developed that reduces the spiral wave dynamics under a long-delayed(More)
Spiral waves are induced in a thin layer of the light-sensitive Belousov-Zhabotinsky reaction and controlled by a time-dependent uniform illumination. The intensity of the illumination is taken to be proportional to the average wave activity observed within a circular domain of the reaction layer. Stabilization and destabilization of spiral waves, as well(More)
Spiral waves rotating in a thin layer of the light-sensitive Belousov-Zhabotinsky reaction can be controlled by the application of short light pulses at instants corresponding to the passage of a wave front through a measuring point. It is shown that such a feedback results in a drift of the spiral wave core along a discrete set of stable circular orbits(More)
The effect of acetone on temporal oscillations and spatio-temporal patterns occurring in the ruthenium-catalyzed Belousov-Zhabotinsky (BZ) reaction was investigated in a closed batch system. The periods of temporal oscillations and waves significantly decrease with increasing acetone concentration. At low concentrations of acetone (0.01-0.05 M), regular(More)
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