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In an operating diesel engine, which of the following condition is an indication of a leaking air starting valve?（）
A . noise coming from that air starting valve
B . continuous operation of the starting air compressor
C . zero air pressure in the air starting system
D . overheated starting air pipe to the cylinder head
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Examine the query and its output executed In an RDBMS Instance:Which three statements are true about the users (other than sys) in the output?（）
A . The C # # B_ADMIN user can perform all backup and recovery operations using RMAN only.
B . The C # # C_ADMIN user can perform the data guard operation with Data Guard Broker.
C . The C # # A_ADMIN user can perform wallet operations.
D . The C # # D_ADMIN user can perform backup and recovery operations for Automatic Storage Management (ASM).
E . The C # # B_ADMIN user can perform all backup and recovery operations using RMAN or SQL* Plus.
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Sludge may form in the crankcase of an air conditioning compressor as a result of （）.
A . bubbling refrigerant
B . overheating and oxidation
C . lowered operating temperatures
D . reducing the cloud or flash point
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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
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The air spaces in the floor of an inflatable liferaft will provide protection against（）.
A . asphyxiation from CO
B . loss of air in the sides of the raft
C . rough seas
D . cold water temperature
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To add refrigerant to the low side of an air conditioning system, the refrigerant should be introduced through the （）
A . suction service valve as a vapor
B . suction service valve as a liquid
C . discharge service valve as a vapor
D . charging valve as a liquid
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In extreme weather conditions, either hot or cold, control of the air conditioning plant presents （） difficulties.
A . few
B . little
C . a little
D . le
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Sludge may form in the lubricating oil crankcase of a reciprocating air conditioning compressor as a result of （）.
A . wax precipitation in the lube oil
B . contamination by dust, scale, or moisture
C . refrigerant bubbles in the lube oil
D . refrigerant reducing the lube oil viscosity
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The main distribution duct in an air conditioning system which contains the cooling coils and filters is called the（）
A . manifold
B . condenser
C . chamber
D . plenum
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The quantity of cooled air delivered by an air conditioning unit should （） the sum of the quantity of air re-circulated to the unit and the quantity mechanically exhausted.
A . balance
B . not balance
C . be more than
D . be less tha
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If plastic film insulation becomes damaged in air conditioning system, （） may form within the film.
A . evaporation
B . condensation
C . liquefies
D . vaporizatio
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For the proper control of the air temperature in an air conditioning system using chilled water circulation, which of the listed conditions should remain constant regardless of load changes?（）
A . Chilled water system supply temperature
B . Chilled water system return temperature
C . Compressor discharge temperature
D . Compressor suction pressure
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Which of the following conditions can cause above normal air temperature to develop in the intake manifold of a four-stroke/cycle turbo-charged diesel engine?（）
A . Clogged air intake falters
B . Piston blow-by
C . A defective after-cooler
D . Faulty exhaust valve
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（） is used for sensing the temperature of the room in the air condition system.
A . An expansion valve
B . An evaporator
C . A thermostat
D . A condenser
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Which of the following conditions can cause below normal air pressure in the intake manifold of a turbocharged diesel engine?（）
A . Excessive piston blow-by to the manifold
B . Insufficient cooling water flow
C . Accumulated water in the air boxes
D . Clogged air intake filter
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Broken valve strips in an operating low pressure, air compressor will cause （）.
A、an immediate crankcase explosion
B、oil contamination in the compressed air
C、a decrease in compressor capacity
D、no immediate loss of the compressed air capacity
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To add refrigerant to the high side of an air conditioning system, you should introduce the refrigerant through the （）.
A . discharge service valve as a vapor
B . suction service valve as a liquid
C . charging valve as a liquid
D . condenser purge valve as a vapor
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In a chilled water air conditioning unit using a reciprocating compressor, the refrigerating effect of the primary refrigerant can be increased by （）.
A . increasing refrigerant pressure in the coil
B . increasing chilled water flow through the cooler
C . sub-cooling the refrigerant in the condenser
D . superheating the refrigerant in the compressor
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In reference to air conditioning, when air attains the maximum amount of moisture it can hold at a specific temperature, it is said to be （）.
A . superheated
B . saturated
C . condensed
D . convected
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The loss of （） from an air compressor could lead to an overheated air discharge and possibly an explosion in the pipelines leading to the air reservoir.
A、lubricating oil
B、compressed air
C、cooling water
D、sealing ring
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“A souk is an open-air marketplace in an Arab country.” In the sentence, the word “souk” means______.
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Heating and air conditioning are examplesof common costs of all departments in a retail store.
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When we stay at a room in a house with central air-conditioning system in summer, we should set the thermostat to a higher level in ______.
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In what way can natural pollutants play an important role in controlling air pollution？
A.They function as part of a purification process.
B.They are dwarfed by the pollutants produced by human activities.
C.They are less harmful to living beings than are other pollutants.
D.They have existed since the Earth developed.
