Sigma Test and Research Centre Mangolpuri, Delhi

Rebound hammer test is conducted to find out the compressive strength of concrete by using rebound hammer. The rebound of an elastic mass depends upon the hardness of the surface when it strikes. When the plunger of rebound hammer is pressed against the surface of the concrete, the pring controlled mass rebounds and the extent of such a rebound depends upon the surface hardness of the concrete.

Female condom is a device that prevents pregnancy and sexually transmitted diseases that can happen during intercourse. This device is gaining importance as it allows women to take control of their health and keep themselves safe. They no longer have to be dependent on their male partner to take responsibility of preventing infections, diseases and pregnancies.

The calorific value of a fuel is the quantity of heat produced by its combustion - at constant pressure and under "normal" conditions.