A method of processing information packets is disclosed which is adapted for a telecommunication apparatus comprising first processing means, second processing means and memory means. A deviation in the air-fuel ratio of each cylinder is detected on the basis of the output signal of the air-fuel ratio sensor disposed in the exhaust pipe and the forcibly changed quantity of the air-fuel ratio. The cooling device may contain a thermally conductive structure, such as a stack of vias and lines, to conduct heat away from the electrically conductive line, and a current blocking structure, such as a reverse biased diode or a capacitor, to block current flow into the substrate. Other embodiments provide servicing fluids comprising proppant particulates and an aqueous fluid wherein at least some of the proppant particulates are at least partially coated with an aqueous tackifier compound.