function [Kg]=Kg(T) 
  %gas thermal conductivity [W/m*C] at T [celsius] 
 
 Tsat=[0:10:370,374.15];
  %saturation temperature in celsius

 Kvap=1e-3*[17.6,18.2,18.8,19.5,20.2,20.9,21.6,22.4,23.2,24.0,24.9,25.8,26.7,27.8,28.9,30.0,31.3,32.6,34.1,35.7,37.4,39.4,41.5,43.9,46.5,49.5,52.8,56.6,60.9,66.0,71.9,79.1,87.8,99.0,114,134,162,199,240];

Kg=interp1(Tsat,Kvap,T);