PropertyValue
http://www.w3.org/1999/02/22-rdf-syntax-ns#type
http://www.w3.org/ns/prov#value
  • I used nitrogen simply because it makes up over 70% of air but you are correct in that pumps are limited mostly by hydrogen, both because it is harder to pump lighter molecules (making cryopumps necessary to catch hydrogen and its ilk) and from hydrogen that has become adsorbed into the container walls.
http://www.w3.org/ns/prov#wasQuotedFrom
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