An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.

The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.

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

When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.

If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.

If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.

Which of the listed pumps is NOT a positive displacement pump?（）

A salinity indicator is used to determine the （）.

An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.

On tank vessels equipped with power operated cargo tank valves, the type of power operator most commonly used is （）.