单选题As the amount of moisture in the air increases, the difference between the dry bulb and wet bulb temperature will （）.A increaseB decreaseC remain unchangedD be greatest at dew point

Restrictions occurring in the small orifices(孔) of pneumatic control system components can be caused by ______.

A.moisture in the compressed air supply

B.excessive dryness in the compressed air supply

C.pressure surging in the compressed air receiver

D.insufficient lubrication of the system components

As the amount of moisture in the air increases, the difference between the dry bulb and wet bulb temperatures will ______.

A.increase

B.decrease

C.remain unchanged

D.be greatest at dew point

Which of the processes listed would be the most satisfactory method to use to lower the humidity of the air being circulated by an air conditioning system?

A.Cooling the air to a temperature just above dew point

B.Heating the air to a point at which moisture will boil off ,then re-cooling it

C.Cooling the air to a point below dew point, then reheating it

D.Heating the air and then cooling it to a point below dew point

The moisture equilibrium chart can be used to determine the ______．

A.Absolute moisture content of the air surrounding a hygroscopic cargo when moisture equilibrium exists

B.Dew point temperature that the air surrounding a hygroscopic commodity will have when in moisture equilibrium with that commodity

C.Enthalpy of the air surrounding a hydroscopic cargo which is in moisture equilibrium with the cargo

D.Temperature at which moisture equilibrium will occur in a cargo hold containing a hygroscopic cargo

In an air conditioning system, moisture is removed from the air by ______.

A.filters

B.separators

C.ducted traps

D.dehumidifiers

Temperature and moisture characteristics are modified in a warm or cold air mass due to ______.

A.pressure changes in the air mass

B.movement of the air mass

C.the heterogeneous nature of the air mass

D.upper level atmospheric changes

Some refrigeration systems have chemical moisture indicators installed in conjunction with the sight glass in the liquid line If excess moisture is present in the system, the indicator will

A.activate the driers

B.change color

C.secure the compressor

D.add a predetermined amount of liquid drier

Whipping the bitter end of a fiber rope ______．

A.increases the circumference of the rope

B.makes for easier handling

C.prevents fraying of the bitter end

D.prevents moisture from entering the bitter end