Water wheels have been used to power mills and pumps for centuries. However, the traditional water wheel was inefficient: water hitting a bucket would splash back against the next bucket, slowing the wheel. This is especially true when water is delivered to the buckets under very high pressure.
The unprecedented innovation of the steam-atmospheric engine by Thomas Newcomen (1663-1729) of Dartmouth and his assistant John Calley stands at the beginning of the development of practical thermal prime movers in the early years of the eighteenth century. Spreading through Europe and then to the Cornwall mines in the New World, it was one of the strategic innovations in world history and the single greatest act of synthesis in the ensuing history of the steam engine.
The Southwest Research Institute Split-Hopkinson Pressure Bar apparatus is a mechanical test instrument used to characterize the dynamic response of materials at high strain rates (typical of impacts and explosions).
The apparatus, based on devices invented by Bertram Hopkinson and Herbert Kolsky, was developed at SwRI in 1962 by Dr. Ulric Lindholm. Initially created to evaluate the behavior of metals under various conditions, the SwRI Split-Hopkinson Pressure Bar has since been applied to a wide range of materials.