A long and thin$-$walled pipe with a radius of r$1=50$ mm is used to transfer steam and the

inner surface temperature of the pipe is kept constant at Ts$1=400$ K$.$ The pipe is covered

with a $50$ mm$-$thick insulation comprised of two different materials. The upper half of the

pipe is covered with material A with a thermal conductivity of kA $=1\mathrm{.}5$ W$/$m$.$K and the

lower half of the pipe is covered with material B with a thermal conductivity of kB $=0\mathrm{.}5$

W$/$m$.$K$.$ The outer surface of the insulated pipe is exposed to air at T$\backslash$infty $=300$ K and h $=30$

W$/$m$2$

$.$K$.$

a$.$ Sketch the thermal resistance network of the system and label

b$.$ Calculate the total heat loss from the pipe

c$.$ Calculate the outer surface temperatures of material A and B $($Ts$,2($A$)$ and Ts$,2($B$))9$