Steam is supplied in a line at 450 lbf/in 2, 1200 F. A turbine with an isentropic efficiency of 85% is connected to the line by a valve and it exhausts to the atmosphere at 14.7 lbf/in 2. If the steam is throttled down to 300 lbf/in 2 before entering the turbine find the actual turbine specific work. Find the change in availability through the valve and the second law efficiency of the turbine.