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Handbook of Micro and Nano Tribology

Records show the use of wheels from 3500 BC, which illustrates our ancestors’ concern with reducing friction in translationary motion. The transportation of large stone building blocks and monuments required the know-how of frictional devices and lubricants, such as water-lubricated sleds. Figure 1.1 illustrates the use of a sledge to transport a heavy statue by Egyptians circa 1880 BC (Layard, 1853). In
this transportation, 172 slaves are being used to drag a large statue weighing about 600 kN along a wooden
track. One man, standing on the sledge supporting the statue, is seen pouring a liquid into the path of
motion; perhaps he was one of the earliest lubrication engineers. (Dowson, 1979, has estimated that each man exerted a pull of about 800 N. On this basis the total effort, which must at least equal the friction force, becomes 172 × 800 N. Thus, the coefficient of friction is about 0.23.) A tomb in Egypt that was dated several thousand years BC provides the evidence of use of lubricants. A chariot in this tomb still contained some of the original animal-fat lubricant in its wheel bearings.

Từ khóa: Nano Tribology, original animal, wheel bearings, military engineers, industrialization, hydrodynamic lubrication

275 p tailieu_mku 03/07/2012 256 1

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