A muscle strain is the stretching or tearing of muscle fibers. Most muscle strains happen for one of two reasons: either the muscle has been stretched beyond its limits or it has been forced to contract too strongly. In mild cases, only a few muscle fibers are stretched or torn, and the muscle remains intact and strong.
Full Definition of HYDROGEN. : a nonmetallic element that is the simplest and lightest of the elements, is normally a colorless odorless highly flammable diatomic gas, and is used especially in synthesis â see element table â compare deuterium, tritium.â hyÂ·drogÂ·eÂ·nous \hÄ«-Ëdrae-ËdrÃ¤-jÉ\ nÉs. adjectiveord History of HYDROGEN. When hydrogen is burned it combines with oxygen to make water. That fact accounts for the name of this gas. The word hydrogen was formed from two Greek roots. The first, hydro- , means â water, â and the second, -gen, means â giving rise to, producing.
Hydrogen fuel is a zero-emission fuel when burned with oxygen (if one considers water not as an emission) or used in a contained cell also capable of 'reversing' the reaction if needed. It often uses electrochemical cells, or combustion in internal engines, to power vehicles and electric devices.