APPENDIX D: 



CALCULATIONS FOR DETERMINING THE 

 KROGH DIFFUSION CONSTANT FOR THE 

 PNEUMATOPHORE WALLS OF NANOMIA 



Below is the protocol followed in calculating K for 

 the float in Experiment 6: 



Float dimensions: 1. 7 mm x 1.0 mm 



Surface area, ^ of a regular prolate spheroid: 



n Ct,t) i 



A = 2nb + 2tt — sin e 



e 



where a and b are the major and minor semi-axes, respec- 

 tively, and e is the eccentricity. 



A = 6.28(. 5) 3 + 6.28 ^' S ^'l ) 1.04 = 4.79 mm 2 



= 4. 79 x 10" 3 cm 3 

 dv dx 760 



K '~ dt ' A ' dp 



From table 3: dv = 2. 3 x 10~ 4 cm 3 



dt = 2.3 x 10 2 min 



Measured thickness of float wall (float width minus gas 

 phase width, -f 2), 



dx = 0. 2 mm = 2 x 10 3 ^ 



Percent carbon monoxide in float gases (partial pressure 

 gradient across float walls): 



at start = 15.6 = 119 mm Hg p CO 



at end =35.0- 266 mm Hg p CO less 13 mm Hg p CO 

 dissolved in syringe 

 = 253 mm Hg p CO 



That is, dp = 119 at start 

 = 253 at end. 



49 



