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Properties of wave propagation in a gel-type belousov-zhabothinsky reaction under micro-gravity
2009 - HANKE, WOLFGANG; SIEBER, MICHAELA; SPENCER, PATRICK; SCHWERTNER, JURGEN; LIMA, VERA M.F. de
The Belousov–Zhabothinsky (BZ) reaction is a chemical reaction which exhibits spatial as well as temporal pattern formation. Being an excitable medium, it can be influenced by even small external forces. One of these small forces which under ground conditions permanently is given is gravity. The gravity dependence of the BZ-reaction has been investigated in some detail up to now, and it has been found that especially the propagation velocity of waves in thin layers of fluid BZ-medium depends significantly on gravity-amplitude and -orientation. This finding has been mainly assigned to an interaction of gravity with diffusion and convection in the medium at the wave front, and consequently it has been stated that the propagation of waves in gels of BZ-medium is not significantly gravity dependent. We have now done more detailed experiments and have been able to show that also in gels the propagation velocity of BZ-waves is altered by gravity, but less than in fluid systems. Experiments have been performed in a lab centrifuge, a sounding rocket experiment and a parabolic flight mission.