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1. What is the % carbon content in cast iron and in mild steel? 2. What is the selection of materials for pipelines ? 3. Which type of cast iron  is brittle in nature and not suitable for used in marine work ? 4. What is % carbon range for steel and % cast iron? 5. What is the significance of iron carbide diagram ?

1. What is a pump ? What are its applications ? Ans. Pump is a device which adds energy to the fluid which is used transfer fluids from one place to another . It is used to transfer sea water , fresh water , fuel such as diesel , hfo , lubricating oil, hydraulic oil which is essential for auxiliary purposes. 2. What is the classification of pump? Ans. There are two types of pumps .          A. Positive displacement pump          B. Rotodynamic pump. 3. What is the difference between these two pumps? Ans.                  Postive Displacement Pump A. Displacement of fluid is achieved by mechanical variation in the volume . B. Capableof  handling with small quantity of fluid with  high pressure . C.Energy addition is periodic. D. Self priming pump. E. Displacement of fluid will results in increase in pr...

Surface tension It is the force of attraction(cohension) between the similar surface particles of fluid which forms films . Reasons : various forces such as vanderwaal forces , hydrogen bonding forms web of water molecules on the surface. Concept : At liquid–air interfaces, surface tension results from the greater attraction of liquid molecules to each other (due to  cohesion ) than to the molecules in the air (due to  adhesion ). The net effect is an inward force at its surface that causes the liquid to behave as if its surface were covered with a stretched elastic membrane.  Eg . A. Ants and other spinder walk through surface of water.        B. Rain drop has a  shape Additional Information : Its dimension is same as that of force per unit length Water has surface tension of 72.8 milli newtons at 20 degree centigrade