The temperature of a gas stream is to be measured by a thermocouple whose junction can be approximated as a 1.2-mm-diameter sphere. The properties of the junction are k = 35 W/m⋅K, rho = 8500 kg/m3, and cp = 320 J/kg⋅K, and the heat transfer coefficient between the junction and the gas is h = 110 W/m2⋅K. Determine how long it will take for the thermocouple to read 99.5 percent of the initial temperature difference.

Agas mixture with a compostion of 55 methane, 30% propane, and 15 butane by volume) is compressed from 1 bar and 25°c to 9bar in a compressor with an isentropic efficiency of 85%. the environment has a temperature of to25 c. determine (a) the exit temperature of the mixture (b) the specific work required to run the compressor (c) the specific entropy generation of the process (d) the specific exergy destruction of the process (e) the second law efficiency of the compressor