L11A
       Polytropic process relation
       Example 3.12

L11B
       Conservation of mass of a control volume
       Evaluate the mass flow rate
       Forms of the mass rate balance
       One-dimensional flow

L11C
       Steady state form of mass rate balance
       Integral form of the mass rate balance
       Application of the mass rate balance
       Example 4.1 applying the mass rate balance to feedwater
       heater at steady state
       Example 4.2 filling a barrel with water

L11D
       Integral form of the control volume energy rate balance
       Steady state forms of the mass and energy rate balance
       Modeling conservation for control volume at steady state