Molten aluminium was poured in a sand mold and the thickness of solid skin formed after $$20$$ seconds and $$50$$ seconds were fond to be $$3mm$$ and $$4.5mm$$ respectively. What would be the thickness of the solid skin at the end of $$100$$ seconds after pouring?

Poor collapsibility of the mold leads to .......... type of casting defect in aluminium castings.

Green strength in powder metallurgy refers to the strength of

The process by which shell like castings (like toys) are made is