The present invention relates to a roofing underlayment system comprising two layers of a coated structural article which comprises a substrate having an ionic charge coated with a coating having essentially the same ionic charge or one layer of such coated structural article in combination with one layer of felt material. The neck member includes an air inlet to receive cooled air from an air source. Individual computing devices receive instructions and data that correspond to a piece of a larger computational problem. The second transceiver unit may receive and transmit packet transactions on a second link of the packet bus. The pulse generator circuit is shared amongst the PWM mode or PFM mode and utilizes a master clock for its operations.