“…However, the effect of the radius will be further considered later, in figure 4. We have taken two different values for T 0 , namely, T 0 = 150 K and T 0 = 100 K. The corresponding wall-accommodation parameters C = 0.36 and C = 0.46 have been taken from Sellitto et al (2010b) and refer to a smooth wall, so that the effective thermal conductivity at T 0 = 150 K and T 0 = 100 K are, respectively, l eff = 23.2 Wm −1 K −1 and l eff = 18.8 Wm −1 K −1 , according to equation (3.1). As it is possible to observe, the temperature behaviour arising from equation (3.2) (solid lines in figure 3) shows a hump; namely, when r < , the temperature increases with radius.…”