O-Rings offer the designer an efficient and economical sealing element for a wide range of static or dynamic applications. Inexpensive production methods and its ease of use have made the O-Ring the most widely used seal.
A wide choice of elastomer materials for both standard and special application allow the O-Ring to be used to seal practically all liquid and gaseous media.
O-Rings are vulcanised in molds and are characterized by their circular form with annular cross section. The dimensions of the O-Ring are defined by the inside diameter d1 and cross section d2.
Poll: Should the UK’s railways be renationalised?
I'd hate to be disingenuous so I've replotted the data with the first trendline from 1946 to 1977 and the second using your chosen dates 1983 to 2018....