For the sake of argument, assume there are 100 work units queued and pending. Threads in the thread pool will not die until all work is extinguished and they have received the shutdown flag.

This paper presents an efficient method to work out the unit startup and shutdown schedule in electric power system based on the optimal and suboptimal unit combination.

Generally desanding of large tank adopts manual desanding that requires personnel to enter the tank after shutdown, with high work burden, severe environment, long shutdown time and low efficiency.