When the line pressure to atmospheric pressure, open the balltube, check pigging or caliper effect.
当管线内压力降到大气压力时，打开收球筒，检查清管或测径效果。
2
The game calls for players to lift a ball inside a transparent tube using their powers of concentration.
游戏要求玩家利用集中力将一个小球上升至一根透明的管中。
3
One day, physicist Ho-Kei Chan of Trinity College Dublin was playing with steel ball bearings, trying to pack them into a little cylindrical tube in the most efficient way possible.