更多"Which characteristic is a disadvant"的相关试题:
[单项选择]Which characteristic of Halon is a disadvantage when it is used as a fire extinguishing medium?（）
A. Leaves a residue
B. Cost，relative to other agents
C. Breaks down while under prolonged storage
D. Conducts electricity
[单项选择]‘Offset’ is an inherent characteristic of which of the follow types of control modes?（）
A. Tow position
B. Proportional
C. Reset
D. Rate
[单项选择]Which is a disadvantage of Halon as a fire extinguishing medium?（）
A. Conducts electricity
B. Difficult to store
C. Large volume necessary to be effective
D. Ineffective in powdered metal fires
[单项选择]Which characteristic or condition will have the greatest effect on increasing a hydraulic oils viscosity?（）
A. Pour point
B. Cloud point
C. Vacuum
D. Pressure
[单项选择]Which of the following characteristic of lube oil helps to reduce the amount of deposits in the piston ring belt during the combustion process in a diesel engine?（）
A. Low viscosity index
B. Low carbon forming tendencies
C. High film strength
D. High non-corrosive qualities
[单项选择]Which of the listed statements is a characteristic of the liquid charged power element used with thermostatic expansion valves?（）
A. At the designed operating temperature, the liquid refrigerant charge has changed to a vapor
B. The liquid refrigerant tends to collect at the bellows or diaphragm and reduces the valve sensitivity
C. The sensing bulb is empty of liquid refrigerant charge at the designed operating temperature
D. The sensing bulb is never emptied of liquid refrigerant under normal operating conditions
[单项选择]Which characteristic is an advantage of Halon as a fire extinguishing medium?（）
A. Electrically non-conductive
B. Relatively inexpensive
C. Effective against chemicals containing an oxidizer
D. All of the above
[单项选择]Which of the following is a characteristic of a Ro-Ro vessel（）.
A. Passenger tours available upon docking
B. Long port stays necessary to secure vehicles
C. Short in port turnaround times
D. Heavy vehicles only require lightweight securing equipment
[单项选择]The voltage developed by an AC generator is controlled by varying the （）
A. speed of the prime mover
B. AC excitation to the field
C. DC excitation to the field
D. DC excitation of the voltage regulator
[单项选择]The disadvantage of using three strand nylon line for towing is its（）.
A. inherent weakness
B. tendency to rot if left damp
C. danger to crew if it parts
D. strength and shock absorbing abilities
[单项选择]On a ship，a cabinet or space containing the controls or valves for the fixed firefighting system must be（）.
A. posted with instructions on the operation of the system
B. ventilated and equipped with explosion-proof switches
C. painted with red and black diagonal stripes
D. equipped with a battery powered source of emergency lighting
[单项选择]The test of a towing vessel’s steering gear control system includes each item EXCEPT（）.
A. a test from the alternative power supply，if installed
B. timing the movement of the rudder from hard over to hard over
C. verification that the rudder angle indicator shows the actual position of the rudder(s)
D. visual inspection of the steering linkage
[单项选择]What is the primary disadvantage of a permanent chain chaser system?（）
A. It requires anchor handling boats with more horsepower
B. Chain chasers work in shallow water only
C. Chain chasers will not work with piggyback anchors
D. It takes longer to deploy anchors using chain chasers
[单项选择]One disadvantage of using regular dry chemical (sodium bicarbonate) in firefighting is that（）.
A. it can break down under high heat and emit noxious fumes
B. it will decompose under prolonged storage and lose its effectiveness
C. fire has been known to flash back over the surface of an oil fire
D. it is ineffective in fighting fires in high-voltage electrical equipment
[单项选择]A disadvantage of using chain lashing on heavy vehicles aboard Ro-Ro vessels is that it is （）.
A. heavy
B. easily damaged
C. affected by temperature
D. costly relative to the strength ratio
[单项选择]The disadvantage of using a heaving line to pass a towline is that（）.
A. it increases the likelihood of collision between the towing vessel and the disabled vessel
B. recreational boaters tend to make the heaving line fast to the towed vessel as if it were the towline
C. the monkey fist may injure someone
D. it may reduce the catenary and increase yawing
[单项选择]A disadvantage of a four-stroke/cycle diesel engine is （）
A. higher working temperature of piston and cylinder
B. the use of scavenge ports
C. fewer power strokes per revolution of the crankshaft
D. part of the fuel is burned as the piston is moving away from top dead center
[单项选择]One major disadvantage of a low-speed diesel as compared to a steam main-propulsion system is（）.
A. the extra weight required for the diesel reduction gearing
B. a minimum speed for the engines that limits the minimum speed of the vessel
C. the higher fuel consumption per SHP
D. the low efficiency of the system when a controllable pitch propeller is used
