A surface water source has a total dissolved solids (TDS) concentration of 400 mg/L and is to be treated with reverse osmosis to produce a water that is 25 mg/L (TDS). If the membrane has an average salt rejection ratio of 0.95, what water recovery ratio should the membrane system achieve?

Air inially occupying a volume of 1 m2 at 100 kpa, 27 c undergoes three internally reversible processes in series. process 1-2 compression to 500 kpa during which pv constant process 2-3 adiabatic expanslon to 100 kpa process 3-1: constant-pressure expansion to 100 kpa (a) calculate the change of entropy for each of the three processes. (b) calculate the heat and work involved in each process. (c) is this cycle a power cycle or refrigeration cycle?