About: http://webisa.webdatacommons.org/115697418

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	It is believed that even if a gas is purified at its source, impurities such as oxygen and moisture can be introduced before the gas enters a processing chamber.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com