A rigid cylinder contains helium (molar mass 4 kg/kmol) at a pressure of S bar and a temperature of 1St. The cylinder is now connected to a large source of helium at 10 bar and 15 °C, and the valve connecting the cylinder is closed when the cylinder pressure has risen to 8 bar. Calculate the final temperature of the helium in the cylinder assuming that the heat transfer during the process is negligibly small. Take for helium as 112 kl/kg K.