A method of fabricating an optical waveguide fiber that includes the steps of providing a cylindrical glass optical fiber preform having a longitudinally extending centerline hole, and closing the hole under conditions suitable to result in uniform and symmetric hole closure. The capacity management tool determines, in response to the received request, one or more actions to perform in the resource pool for performing the requested capacity management operation in compliance with defined operational parameters of the workloads. The ethylene stream is divided into a first ethylene product stream and an ethylene co-feed stream, which is fed subsequently to the overhead stream to a pressure swing adsorption process producing an adsorber effluent stream during an adsorption step and a desorbed stream on desorption. The drive-power-supply device 18 controls drive power to be supplied to the stator coil 17.