Proceedings Of The Marine

SUM 2015

Proceedings magazine is a communication tool for the Coast Guard's Marine Safety & Security Council. Each quarterly magazine focuses on a specific theme of interest to the marine industry.

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64 Proceedings Summer 2015 www.uscg.mil/proceedings A nswers Engineering 1. A. oxidizing fame Incorrect answer. The oxidizing fame which features an excess of oxygen relative to fuel is seldom used for oxyacetylene welding due to excessively high weld temperature and oxidation issues. B. neutral fame Incorrect answer. The neutral fame which features equal portions of oxygen and fuel is the most commonly used fame for oxyacetylene welding including most steels. C. nitriding fame Incorrect answer. Although nitriding is a process used for case-hardening, it is not a type of oxy- acetylene fame. D. carburizing fame Correct answer. The carburizing fame which features an excess of fuel relative to oxygen is used for welding high carbon steels, case-hardening, and the welding of certain nonferrous alloys, such as monel. 2. Note: In any fuel injection system, injection pressure must be accurately controlled to ensure adequate penetration of atomized fuel into the pressurized cylinder for complete combustion. A. engine speed Incorrect answer. In a common rail injection system, injection rail pressure is maintained at a constant value independent of engine speed. B. varying the fuel pump piston stroke Incorrect answer. In a common rail injection system, fuel pump piston stroke lengths are fxed. C. varying the injector needle valve clearance Incorrect answer. In a common rail injection system, the injector needle valves are hydrau- lically operated internally, similar to the methodology used in conventional fuel injection systems. D. a bypass valve Correct answer. In a common rail injection system, a spring loaded bypass relief valve, in conjunction with an accumulator, is used to maintain a constant rail pressure independent of engine load or speed. 3. A. once in every calendar year. Incorrect answer. Choice "D" is the only correct answer. B. 5 years Incorrect answer. Choice "D" is the only correct answer. C. 8 years Incorrect answer. Choice "D" is the only correct answer. D. 12 years Correct answer. Paragraph ยง147.65 (a) states: "Carbon dioxide or halon cylinders forming part of a fxed fre extinguishing system must be retested, at least, every 12 years." 4. A. atmospheric drain tank Incorrect Answer. The atmospheric drain tank (ADT) generally returns condensate to the main and/or auxiliary condenser via a vacuum drag line. The condensate pump then discharges the condensate to the deaerating feed heater (DFT). Thus, any condensate being dumped to the ADT would remain in the condensate system, and the DFT water level would remain high. B. reserve feed tank Correct Answer. Dumping the condensate to the reserve feed tank removes it from the con- densate system allowing the DFT water level to drop. C. auxiliary condenser Incorrect Answer. Any condensate dumped to the auxiliary condenser would remain in the condensate system, and the DFT level would remain high. See explanation for Choice "A". D. main condenser Incorrect Answer. Any condensate dumped to the main condenser would remain in the con- densate system and, the DFT level would remain high. See explanation for Choice "A".

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