About: http://webisa.webdatacommons.org/98801481

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	The disk constitutes the working face and is made as rigid as possible to vibrate as a piston; to this end, it is preferably relatively thick and of some relatively light, strong material, such as aluminum.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com