Pattern Formation in the Belousov−Zhabotinsky Reaction with Photochemical Global Feedback

2000 ◽  
Vol 104 (49) ◽  
pp. 11566-11577 ◽  
Author(s):  
Vladimir K. Vanag ◽  
Anatol M. Zhabotinsky ◽  
Irving R. Epstein
Keyword(s):  
Pattern Formation ◽  
Belousov Zhabotinsky Reaction

scholarly journals Spatial Heterogeneity and Imperfect Mixing in Chemical Reactions: Visualization of Density-Driven Pattern Formation

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
Sabrina G. Sobel ◽  
Harold M. Hastings ◽  
Matthew Testa
Keyword(s):  
Pattern Formation ◽  
Salt Water ◽  
Model System ◽  
Reaction Vessel ◽  
Chemical System ◽  
Industrial Processes ◽  
History Of ◽  
Convection Rolls ◽  
Belousov Zhabotinsky Reaction ◽  
Complex Ion

Imperfect mixing is a concern in industrial processes, everyday processes (mixing paint, bread machines), and in understanding salt water-fresh water mixing in ecosystems. The effects of imperfect mixing become evident in the unstirred ferroin-catalyzed Belousov-Zhabotinsky reaction, the prototype for chemical pattern formation. Over time, waves of oxidation (high ferriin concentration, blue) propagate into a background of low ferriin concentration (red); their structure reflects in part the history of mixing in the reaction vessel. However, it may be difficult to separate mixing effects from reaction effects. We describe a simpler model system for visualizing density-driven pattern formation in an essentially unmixed chemical system: the reaction of pale yellow Fe3+ with colorless SCN− to form the blood-red Fe(SCN)2+ complex ion in aqueous solution. Careful addition of one drop of Fe(NO3)3 to KSCN yields striped patterns after several minutes. The patterns appear reminiscent of Rayleigh-Taylor instabilities and convection rolls, arguing that pattern formation is caused by density-driven mixing.

Pattern formation in the splay Freedericks transition of a nematic side-group polysiloxane

1993 ◽  
Vol 3 (6) ◽  
pp. 865-889 ◽  
Author(s):  
Norbert Schwenk ◽  
Hans Wolfgang Spiess
Keyword(s):  
Pattern Formation ◽  
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