A structure to generate x-rays has a plurality of stationary and individually electrically addressable field emissive electron sources with a substrate composed of a field emissive material, such as carbon nanotubes. In the process, the logs are cut into billets with a cross cut circular saw immediately after the logs are heated and before the logs are permitted to cool to a temperature below a suitable extruding temperature. The method may further include determining, by the one or more computer processors, a predicted zone in the vicinity of the first machine based on the projected position of the first machine. In embodiments, storage devices may be classified into different classes of storage to implement a multi-class file system. The clamp includes clamp arms which protrude on both sides of the pivotable bearing, which partially enclose, respectively, the stator. The control system measures the temperature of the drum, determines a difference between the temperature of the drum and a target temperature, and directs the cooling system to vary an application of the coolant to the drum based on the difference to maintain the drum at the target temperature.