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.
Electric motor bearings. The purpose of a bearing in an electric motor is to support and locate the rotor, to keep the air gap small and consistent and transfer the loads from the shaft to the motor. The bearings should be able to operate at low and high speeds whilst minimizing frictional loses.