EFFECT OF MICROGRAVITY ON THE SPATIAL OSCILLATION BEHAVIOR OF BELOUSOV-ZHABOTINSKY REACTIONS CATALYZED BY FERROIN

The propagation behavior of chemical waves in the Belousov-Zhabotinsky reaction was examined experimentally for the first time under microgr avity conditions. This study was motivated by the work of Kondepudi an d Prigogine (1981), who pointed out theoretically that a diffusion rea ction system with nonlinear and nonequilibrium characteristics may rec eive a great amplification of the subtle effect of gravity on elementa ry reactions. In the present study, the free-fall facility at the Japa n Microgravity Center in Hokkaido (JAMIC) was utilized to maintain a q uality of 10(-5) g for about 10 s. To prevent convection due to surfac e tension, a thin planar vessel closed to air was used in both normal and microgravity runs. Concentric patterns induced spontaneously in th e vessel fixed in the vertical position were elongated downward and sh ortened upward under normal gravity. Under microgravity, however, prop agation speed was almost the same in traveling directions. To discuss the effect of convection, propagating speed in gel matrix was also obs erved in similar experiments under microgravity conditions, but no app arent influence was revealed.