Q41. Which furnace burns low-ash fusion coal and retains most of the coal ash in the slag? Ans: Cyclone furnace.

Answer – Cyclone furnace.

Q42. What does Greenfield project mean?

Answer – Greenfield projects are those projects, which do not create any environmental nuisance (pollution), follows environmental management system and EIA (environment impact assessment). These projects are usually of big magnitude.

Q43. Why is boiler purged every time before starting firing of fuel? 

Answer – Purging ensures that any unburnt fuel in furnace is removed, otherwise it may lead to explosion34. Is it the stress that, produces strain or strain produces stress?

Q44. Is it the stress that, produces strain or strain produces stress?

Answer – A Force applied to an object will cause a displacement. The strain is effectively a measure of this displacement (change in length divided by original length).
Stress is the Force applied divided by the area it is applied. (E.g. pounds per square inch)
Therefore, to answer the question, the applied force produces both “Stress and Strain”. “Stress and Strain” are linked together by various material properties such as Poisson’s ratio and Young’s Modulus.

Q45. What is the principle of mechanical refrigeration?

Answer – A volatile liquid will boil under the proper conditions and in so doing will absorb heat from surrounding objects.

Q46. How does iron ore turn into steel?

Answer – To make Steel, Iron Ore is refined into iron and all the carbon is burned away using very high heat (Bessemer). A percentage of Carbon (and other trace elements) are added back to make steel. 36. What is knurling?
Knurling is a machining process normally carried on a center lathe. The act of Knurling creates a raised crisscross pattern on a smooth round bar that could be used as a handle or something that requires extra grip.

Q47. What type of boiler does not need a steam drum?

Answer – Supercritical pressure boiler.

Q48. What is the mechanical advantage of a double pulley?

Answer – It only takes half the effort to move an object but twice the distance.

Q49. Why are large boilers water tube type? 

Answer – Water tube boilers raise steam fast because of large heat transfer area and positive water circulation. Thus they respond faster to fluctuations in demand. Further single tube failure does not lead to catastrophe.

Q50. What is extruded aluminum?

Answer – Extrusion is the process where a metal or a metal bar is pulled through a mandrel to elongate it and/or give it a final shape.

Extruded Aluminum is a common form of making small aluminum wire, bars or beams and many varieties of small non-structural, decorative pieces.