Image: Halliburton. Downhole camera technology puts eyes underground, enhancing a company's understanding of what is going on within the furthest depths of production and helping operators make important decisions that benefit from the all too valuable sense of sight.
Barium was discovered by Sir Humphrey Davy at 1808 in England. Origin of name: from the Greek word barys meaning heavy Baryta (barium oxide, BaO) was distinguished from lime (calcium oxide, CaO) by Scheele in 1774.
The aufbau method was originally proposed by the great Danish physicist Niels Bohr who was the first to bring quantum mechanics to the study of atomic structure and one of the first to give a fundamental explanation of the periodic table in terms of arrangements of electrons (electronic configurations).