On-Uma Kheowan

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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)
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)
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)
Front deformation of initially planar excitation waves can be observed in nonplanar media or in spatially heterogeneously illuminated systems. The deformation of propagating reaction–diffusion waves in either of these systems has been investigated earlier separately. Here we present a combination of both heterogeneous systems, which can lead to a(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)
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)
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