單項(xiàng)選擇題The most common cause of scale formation in an auxiliary boiler is ()

A.concentrations of calcium sulfate in the boiler water
B.fuel oil in the feed water
C.improper treatment of the feed water with calcium sulfate
D.excessive feed water alkalinity


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1.單項(xiàng)選擇題For proper operation, auxiliary boiler feed water must have which of the following characteristics?()

A.High oxygen concentration
B.Low pH
C.Proper alkalinity
D.All of the above

2.單項(xiàng)選擇題If a four-stroke/cycle diesel engine is running at 1550 RPM, the speed of the camshaft will be().

A.525 RPM
B.775 RPM
C.1550 RPM
D.1800 RPM

3.單項(xiàng)選擇題An indication of a diesel engine air intake being partially clogged, is ().

A.low firing pressure and low exhaust temperatures
B.low firing pressure and normal exhaust temperatures
C.high firing pressure and low exhaust temperatures
D.high firing pressure and high exhaust temperatures

4.單項(xiàng)選擇題The closing of the exhaust valves used on a modern, large, low-speed, main propulsion diesel engine may be directly provided by ().

A.large conical springs
B.compressed air pressure
C.hydraulic pressure
D.exhaust gas pressure