In simple words, an Oxygen Concentrator works on electricity; takes in room air, removes Nitrogen from it and provides upto 95% pure Oxygen. The composition of air (78% Nitrogen, 21% Oxygen and 1% other gases like Carbon Dioxide, Argon, etc.) clearly shows that air is mainly comprised of two gases: Nitrogen and Oxygen [together 99%].
Word Origin and History for savoir-faire Expand. n. instinctive knowledge of the right course of action in any circumstance, 1815, from French, literally to know (how) to do, from savoir to know (from Latin sapere; see sapient) + faire (from Latin facere; see factitious).
The sinoatrial node (SA node): is a small strip of tissue that contains specialized cells. The SA node lies in the wall of the right atria close to the opening of the superior vena cava. Cells of the SA node set the pace of the heartbeat under normal conditions.