A process for reducing the viscosity of fracturing fluids in downhole oilfield operations is provided. An originator requests or provides a key to the key server, optionally with an assertion from an authentication authority. In one example embodiment, the propagation of energy through a mechanical spring is simulated using dispersive waveguides, wherein left-going and right-going waves are separately processed, and the effects of dispersion and attenuation commuted to the waveguide ends. The back wall of the fan housing also includes a pair of bend down tabs that can be placed in contact with the bottom surface of the joist to correctly position the bottom edge of the fan housing the required distance from the joist to accommodate the most common drywall thickness.