题目内容

Oil Pollution Regulations require any transfer or discharge of oil or oily mixtures to be

A. bridge log
B. Master's log
C. engine room log
D. oil record

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第二组
The only attention that heat exchanger should require is to ensure that the heat transfer surfaces remain substantially clean and the flow passages generally clear of obstruction. Indication that undue fouling is occurring is given by a progressive increase in the temperature difference between the two fluids, over a period of time, usually accompanied by a noticeable rise in pressure loss at a given flow.
Fouling on the sea-water side is the most usual cause of deterioration in performance. The method of cleaning the sea water-side surfaces depends on the type of heat exchanger. With shell-and-tube heat exchangers, the removal of the header covers or, m the case of the smaller heat exchangers, the headers themselves, will provide access to the tubes. Obstructions, dirt, scale etc., can then be removed, using the tools provided by the heat exchanger manufacturer. Flushing through with fresh water is recommended before a heat exchanger is returned to service. In some applications, such as piston oil cooling, progressive fouling may take place on the outside of the tubes. Most manufactures recommend a chemical flushing pr6cess to remove this in situ~ without dismantling the heat exchanger.
Plate heat exchangers may be cleaned by unclamping the stack of plates and mechanically cleaning the surface of each plate as recommended by the manufacturers. The plate seals may require replacement from time to time and here the manufacturers&39; instructions should be closely followed
By which of the following indication, can we conclude that the lube oil-sea water heat exchanger is unduly fouled?

A. the heat exchanger lube oil inlet temperature lowering
B. the heat exchanger sea-water outlet pressure rise
C. the heat exchanger temperature difference between lube oil and sea water increasing
D. the heat exchanger pressure difference between sea water inlet and outlet decreasing

外购成品活塞和配制活塞的尺寸、形状、位置精度和表面粗糙度等均应符合______要求

A. 说明书
B. 规范
C. 设计图纸
D. 船东

The______tool is used in precision work to smooth or enlarge a slightly undersized hole

A. round out
B. round file
C. reamer
D. hole driller

如果实际GDP的供给量等于需求量,那么________。

A. 名义GDP必须等于实际CDP
B. 实际GDP必须等于潜在GDP
C. 实际GDP必须大于潜在GDP
D. 实际G。DP可能大于,等于或者小于潜在GDP
E. 实际GDP必须小于潜在GDP

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