“…Such problems are interesting from the purely mathematical point of view. Moreover, they have potential applications in various fields such as flow through porous media [1], thermorheological fluids [2], image processing [5,10], and especially electrorheological fluids (an essential class of non-Newtonian fluids), which have been used not only in fast-acting hydraulic valves and clutches, brakes, and shock absorbers, but also in some new fields such as accurate abrasive polishing, robotics, and space technology [3,18].…”