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

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

An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.

Thermostatic expansion valves can be adjusted for （）.

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

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

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

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

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