Athenian cultural dominance continued throughout the Roman period, and the buildings added to the Agora reflect the educational role of the city, a role that ended only with the closing of the pagan philosophical schools by the Christian emperor Justinian in A.D. 529.
Bearing, in machine construction, a connector (usually a support) that permits the connected members to rotate or to move in a straight line relative to one another. Often one of the members is fixed, and the bearing acts as a support for the moving member. Most bearings support rotating shafts against either transverse (radial) or thrust (axial) loads.
Radial bearings accommodate loads that are predominantly perpendicular to the shaft. The bearings are typically classified by the type of rolling element and shape of the raceways. Deep groove ball bearings. single row (â Single row deep groove ball bearings 1  ) open basic design (fig. 1)  with shields.