An isolated muscle with cylindrical shape is stimulated repeatedly until the concentration of lactate in the muscle reaches C0 = 1 mol/m3. At that point, stimulation ceases and the muscle is allowed to cool in lactate-free saline. Muscle radius = 0.5 cm, muscle length = 30 cm, mass transfer coefficient for lactate in saline kA = 2x10-7 m/s, lactate muscle-saline partition coefficient %u0444lactate,muscle,saline = 0.5, lactate diffusion coefficient = 2x10-8 m2/s.
(a) How many seconds will it take for the lactate concentration at the center of the muscle to drop to one-tenth the initial value?
(b) Find the initial rate of lactate loss from the muscle (in mol/s).