PLZ HELP! TIMED! Which workers are provided access to protective respirators?

those who have a medical condition that causes breathing problems

those who have earned access through their work ethic

those who have a written protocol for respirator use

those who work in an area where there is a lot of dust, smoke, or fumes in the air

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?