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

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

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

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

Thermostatic expansion valves can be adjusted for （）.

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?（）

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 （）.

Low compressor head pressure in a refrigeration system can be caused by（）.

Which of the following statements is correct concerning heat transfer?（）