A horizontal pipeline is designed for a given E (epsilon), L, Q (flow rate), density, viscosity, and change in pressure, and the resulting diameter is calculated to be a certain value D. It is then found that scaling or corrosion is likely to occur, and that E may rise tenfold, giving f (Fanning friction factor) about twice as large as originally thought. In order to maintain the same values for Q and change in pressure, by what ratio should the design diameter be increased over its original value to allow for scaling and corrosion?