更多"Which of the following gases repres"的相关试题:
[单项选择]Which of the following represents the significance the fuel oil cetane number?（）
A. The cetane number has no affect on injection lag
B. The cetane number is an indication of the fuel’s viscosity
C. Ignition lag is reduced with fuels having a high cetane number
D. The cetane number is of little significance in the combustion
[单项选择]Which of the following represents the maximum percent of oxygen by volume required to be achieved by a ship’s inert gas system, prior to the commencement of crude oil tank washing?（）
A. 6%
B. 8%
C. 10%
D. 12%
[单项选择]Which of the following represents the emergency signal for fire aboard ship?（）
A. More than six short blasts and one long blast on the whistle
B. Continuous blast of the ships whistle for a period of not less than 10 seconds supplemented by the same signal on the general alarm
C. Three short blasts of the whistle supplemented by the same signal on the general alarm
D. More than six short blasts and one long blast on the whistle supplemented by the same signal on the general alarm
[单项选择]Which of the following statements represents the reason for rolling over a diesel engine with the cylinder indicator cocks open prior?（）
A. To test the starting system
B. To remove air bubbles from the jacket water
C. To ensure that the lube oil system delivers pressure
D. To ensure foreign material (water etc) is not present in the cylinders
[单项选择]Which of the following reasons represents why the designed compression ratio of a gasoline engine is lower than that of a diesel engine?（）
A. compression must be low for effective spark ignition
B. compression must be low for required horsepower and torque generation
C. compression must be low to prevent pre-ignition
D. compression must be low to have effective pre-ignition
[单项选择]Which of the following statements represents an advantage of an electromagnetic clutch?（）
A. Large misalignments can be tolerated between the shaft and engine coupling
B. Slip is held to a minimum when reversing shaft rotation
C. Engine torsion vibrations to the driven shaft are eliminated
D. It aids in maintaining power factor
[单项选择]Which of the following statements represents the FIRST precaution to be taken prior to working on any installed electrical component （）
A. Wear rubber gloves and boots
B. Use only approved non-conducting tools
C. Ground the case of the machine before beginning any repairs
D. Open the supply circuits and tag the switches
[单项选择]Which of the following statements represents the advantage of rotary pumps as compared to reciprocating pumps?（）
A. The high discharge pressure of the rotary pumps permits a larger volume of fluid per unit time than the reciprocating pump
B. Rotary pumps are capable of pumping more fluid than reciprocating pumps of the same weight
C. Rotary pumps occupy only one-half the space of reciprocating pumps
D. Rotary pumps eliminate discharge slippage of the pumped liquid, while this does not hold true for a reciprocating pump
[单项选择]Which of the following statements represents the main difference between a relay and a contactor?（）
A. Contactors control current and relays control voltage
B. A relay is series connected and a contactor is parallel connected
C. Contactors can handle heavier loads than relays
D. Contactors are made from silver and relays are made from copper
[单项选择]Which of the following statements represents the correct action to take when three crew members discover a fire?（）
A. One man report the fire, and the other two men fight the fire
B. One man report the fire, one man fight the fire, and one man evacuate and secure the area
C. One man report the fire, one man fight the fire, and one man act as a safety observer
D. All three men fight the fire and report it immediately after it is extinguished
[单项选择]Which of the following statements represents the function of the compression rings installed at the top of a diesel Engine piston?（）
A. Control the amount of lube oil burned in the combustion chamber
B. Transmit heat from the piston to the cylinder liner
C. Prevent damage to ring groove inserts by acting as a heat dam
D. Dissipate combustion chamber gas pressure by channeling it through the ring gap
[单项选择]Which of the following terms represents the form of heat removed from the refrigerant in the condenser of a refrigeration system?（）
A. Latent heat of vaporization
B. Heat of compression
C. Superheat
D. All of the above
[单项选择]As to the bearing, of the following, which statement is not true?（）
A. ff overheat is found, the engine must be stopped for inspection
B. Much heat of the crankcase door indicates that the bearing is overheated
C. If bearing clearance is too large, knocking will be heard in the crankcase
D. If bearing clearance is too large or too small, the white metal may be melted
[单项选择]As to the piston cooling, of the following, which statement is not true?（）
A. Because the piston is exposed to very high temperature, it must be cooled
B. The lower the piston cooling temperature is, the better it is
C. Both water and lube oil can be used as coolant
D. One of the piston cooling methods is vibration cooling, with better effect
[单项选择]Which condition represents the appropriate time for setting off distress flares and rockets? （）
A. Only when there is a chance of their being seen by rescue vessels
B. At half hour intervals
C. At one hour intervals
D. Immediately upon abandoning the vessel
[单项选择]Which of the listed effects represents the purpose of heat treating steel?（）
A. Develop ductility
B. Improve machining qualities
C. Relieves stresses
D. All of the above
[单项选择]Which of the problems listed represents the major difficulty encountered with thermal expansion valve operation?（）
A. Lube oil passing through the system
B. Moisture or foreign matter collecting at the valve seat and orifice
C. Variable spring tension caused by the changing temperature
D. Frost on the liquid line
