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.
Slewing ring bearings have many advantages in applications where the bearing must support an upper structure and facilitate its rotation. Typically large-diameter combination load bearings that lie flat, they are widely used in heavy equipment, such as cranes, excavators, aerial platforms, radar, wind turbines, and material handling equipment.