Dislocations are ________ defects?

Hardest material so far found is________?

Cocks are used to control ________?

From pollution control point of view, the maximum permissible concentration of sulphur dioxide in atmospheric air is about ________ ppm?

Tube side pressure drop in a 1-2 heat exchanger (for turbulent flow of fluids through the tubes) is about ________ times, that in a 1-1 heat exchanger having the same size & number of tubes and operated at the same liquid flow rate?

Steam consumption in kg/hr in case of an evaporator is given by (where, C & E are capacity the economy of the evaporator respectively)?