Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）

The output volume of a positive fixed displacement pump can be changed only by （）.

The rate of heat transfer from a hot region to a cold region is affected most by the （）.

One cause of high head pressure occurring in a refrigeration system can be （）.

Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.

The usual symptoms of cavitation in a centrifugal pump is （）.

Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）

The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）

If you are given the job of adding hydraulic fluid to a mooring winch, and are not certain as to the type of fluid to use, you should （）.

Thermostatic expansion valves can be adjusted for （）.