For flow of a fluid at right angle to a circular cylinder, the average Sherwood number $($averaged around the periphery of the cylinder$)$ can be written as a function of Reynolds and Schmidt numbers by the following equation: Sh

av

$$

$=0\mathrm{.}43+0\mathrm{.}532$Re

$0\mathrm{.}5$

Sc

$0\mathrm{.}31$

for IRe A $10-$cm long, $1-$cm diameter cylinder of uranium hexafluoride $($UF

$6$

$$

$)$ is exposed to an airstream that flows normal to the cylinder axis at a velocity of $1$ m$/$s$.$ The surface temperature of the solid is $303$ K$,$ at which the vapor pressure of UF$6$ is $27$kPa. The bulk air is at $1$ atm and $325$ K$.$ Estimate the rate of sublimation of the cylinder. DATA: Binary diffusity of U

$6$

$$

$-$air gas mixture $=9\mathrm{.}04\backslash$times $10$

$2$

cm

$2$

$/$s