  Fractional diffusion equations are widely used to describe anomalous
diffusion processes where the characteristic displacement scales as a power of
time. For processes lacking such scaling the corresponding description may be
given by distributed-order equations. In the present paper we consider
different forms of distributed-order fractional kinetic equations and
investigate the effects described by different classes of such equations. In
particular, the equations describing accelerating and decelerating
subdiffusion, as well as the those describing accelerating and decelerating
superdiffusion are presented.
