Class of viscous magnetohydrodynamic type-I cosmologies

Bianchi type-I models with a powers-of-t metric are investigated as solutions of the Einstein field equations for a viscous fluid with or without a magnetic field. Solutions are found which satisfy linear thermodynamic relations as well as all energy conditions. In general, these solutions contain a tilting velocity and depend on two parameters which satisfy certain restrictions. In the magnetohydrodynamic case solutions are shown to exist when the magnetic field and the spatial component of the velocity vector are parallel and also when they are perpendicular