The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.

The general purpose of a heat exchanger is to （）.

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

Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.

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

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

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

Thermostatic expansion valves can be adjusted for （）.

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

A pressure drop through the refrigerant liquid line may cause （）.