دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

a surface piston driven pumping unit, similar to a beam lift unit.

n: a body of air that remains for an extended period of time over a large land or sea area with uniform heating and cooling properties. The air mass will acquire characteristics (such as temperature and moisture content) of the underlying region.

n: an area over which an air mass rests and develops temperature and moisture characteristics typical of that location.