更多"Which of the following statements i"的相关试题:
[单项选择]Which of the following statements is true regarding the installation of piston rings on two-stroke/cycle, diesel engines as compared to four-stroke/cycle, diesel engines?()
A. In a two-stroke/cycle engine, the rings run hotter, requiring the end gap to be greater
B. Some provision must be made in a two-stroke/cycle engine to keep the rings from binding in the ports
C. No gap is required to exist between the ends of the ring when cold in a two-stroke/cycle engine, but a small gap is required in a four-stoke/cycle engine
D. The gaps should be staggered on either side of a piston in a two-stroke/cycle engine, while staggering is not necessary in a four-stroke/cycle engine
[单项选择]Which of the following statements is TRUE regarding automatic identification systems (AIS)? ()
A. AIS is a short-range VHF-FM system that automatically broadcasts a vessel's position,course,speed and other safety related information to all those with similar equipment in the area
B. AIS is a one-way centrally managed system that requires the local VTS to send commands to instruct each vessel to broadcast position,course,speed and other safety related information to all those with similar equipment in the area
C. AIS is a global tracking system that relies upon INMARSAT C service to communicate vessel position,course,speed and other safety related information to all those with similar equipment in the area
D. AIS is a short-range 3 cm X-band radar system that automatically sends a vessel's position,course,speed and other safety related information to all those with similar equipment within the area
[单项选择]Which of the following statements is true concerning centrifugal pumps?()
A. They are particularly suited for pumping high viscosity fluids
B. They are started with the discharge valve opened
C. The flow of liquid is developed by imparting energy due to the rotation of an impeller
D. They are always mounted in a horizontal position
[单项选择]Which of the following statements is/are true regarding hydraulic pumps in general? ()
A. Variable volumes can be obtained with gear pumps only by variation of the pump drive speed
B. A radial piston pump houses sliding pistons in a stationary cylinder block through which passes a rotating pintle or ported shaft
C. The amount of fluid displaced per revolution of an axial piston rotary pump is dependent on the angle formed between the cylinder block and valve plate
D. All of the above