Among various plastic hoses, silicone hose has the highest diffusion coefficient for diffusion

of nitrogen gas, which is kept under pressure, through the walls. By using shell balance

method, derive the concentration profile for diffusion process. Explain how the flux

changes with respect to the plastic hose types that are given in the table below. $($Boundary

conditions:@ r$=$Ri $,$ CA$=$ CAi and @ r$=$R$0,$ CA$=$ CA$0).$

Material DAB for N$2$ gas

$($cm$2/$s$)$

Teflon $1\mathrm{.}25$

Nylon $60\mathrm{.}00224$

PVC $0\mathrm{.}014$

Silicone $400$