![]() ASTM D445–12 covers the range of kinematic viscosities 0.2 to 300000 mm2 s-1 (2 × 10-7 to 0.3 m2 s-1) and we note that 10-4 m2 s-1 = 1 stoke. This standard involves measuring the time taken for the liquid to descend a calibrated capillary. ![]() What Johnson & Auth (1951) called ASTM D445-2T has now become ASTM D445–12 (ASTM International, 2013), which may well have successive revisions. They are analogue quantities, depending on whether momentum, heat or mass is being transferred. Kinematic viscosity has dimensions length2 time-1 as do thermal diffusivity and diffusion coefficient. Johnson & Auth (1951) cites ASTM D445-2T ‘Method of Test for Kinematic Viscosity’, and an examination of this follows. By this time standards bodies had been established in many countries and ISO, an international network of standards bodies, had been formed with its headquarters in Geneva. This created, by the middle of the 20th Century, ASTM standards for the viscosity of petroleum products (Johnson & Auth, 1951). Taking into account the range of applications for petroleum products, from gasoline to heavy residue, viscosity / resistance to flow became important quantities in usage. The earliest ASTM standards for the oil industry were concerned with flash points (Jones, 2005). At that time the oil industry was expanding quickly, and procedures for characterising oil products soon started to come within the scope of ASTM. When the American Society for Testing and Materials (ASTM) came into existence in 1898, its first assignment focused on materials and dimensions for rail tracks.
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