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).
Vino Da Tavola (VdT, in the wine books) is the lowest class of wine, a wine made by the producer as he sees fit to make it. There are few rules, other than that the stuff not be poisonous. Most is insipid, thin, weak, and acidic, the sort of wine that used to be sold in jugs and is now sold in tetrapacks.