2.4. Chemical and Other Oscillators 1.Chemical Oscillators 2.The Beating Heart

Chemical Oscillators Ingredients Initial Molar Concentration 150mlSulfuric acid ( H 2 SO 4 )1M 0.175g Cerium ammonium nitrate Ce(NO 3 ) 6 (NH 4 ) M 4.292g Malonic acid CH 2 (COOH) M 1.415g Sodium bromate NaBrO M Belousov-Zhabotinski (BZ) chemical reaction

1.The malonic acid and cerium ammonium nitrate are dissolved and stirred in the sulfuric acid. 2.Resultant solution is initially yellow but turns clear after a few minutes. 3.On adding the sodium bromate, the solution oscillates between yellow and clear with a period of about 1 minute. By adding a few ml of 0.025M Ferroin ( 1,10 phenanthroline iron ), the periodic color change will then be between red and blue.

The Oregonator h~1/2 is a fudge factor Chemical Species Symbol BrO 3  A HBrO 2 X Br  Y Ce 4+ Z All others*

Treating A as a constant:

( , p, q, h all positive) Normalized Equations: Set

The Oregonator:MF07.nbMF07.mwsMF07.nbMF07.mws Oscillatory behavior of Ce4+ concentration (z) vs time (t). Evolution of chemical system onto limit cycle in 3D phase space.

The Beating Heart Electrocardiogram recording for a normal heart. Relaxation oscillator Chaotic heart action is a precursor of sudden death.