Comment on: Preparation, microstructure, and electrorheological property of nano-sized TiO2 particle materials doped with metal oxides

We comment on the shear stresses of recently reported Na-doped, Zr-doped, Al-doped, and Ce-doped TiO2-based electrorheological (ER) suspensions under applied electric strengths. Using deduced critical electricfield strength and additional scaled parameter, we found that the shear stresses could be analyzed using the universal yield stress equation, collapsing the data of Na-doped, Zrdoped, Al-doped, and Ce-doped TiO2 ER fluids onto a single curve