Generally, materials will degrade over time due to fatigue, environmental conditions, or damage incurred during operation. Repair of certain materials during their lifecycle (especially those with structural functions such as concrete) can be very expensive and labour intensive.  Therefore Scientists began developing self-healing materials ,  those artificial (synthetic) substances that …

Historically, most terrorist attacks on civilian targets have involved the use of firearms or explosives, and current defensive strategies are aimed at preventing attacks perpetrated by such means. However, the use of the nerve agent sarin in 1995 to attack the Tokyo subway system, the use of the U.S. mail …