An integrated series of operations through which material and /or energy are converted form o anoter-
-has a definite end
-material is put in, process,and discharged
-applies to more than just reactors (washing machine for example)
-material enter and leave in uninterrupted steams.
-periodic shutdown is required.
-Garden sprinker.
-some material are charged/discharged at intervals while some enter/exite continuously.
-biotechnology industry, to add nutrients.