Quasi-Rip and Pseudo-Rip Universes Induced by the Fluid Inhomogeneous   Equation of State
  We investigate specific models for a dark energy universe leading to Quasi-Rip and Pseudo-Rip cosmologies. In the Quasi-Rip model the equation of state parameter w is less than -1 in the first stage, but becomes larger than -1 in the second stage. In the Pseudo-Rip model the Hubble parameter tends to a constant value in the remote future, although w is always less than -1. Conditions for the appearance of the Quasi-Rip and the Pseudo-Rip in terms of the parameters in the equation of state are determined. Analogies with the theory of viscous cosmology are discussed. 
I. Brevik, V. V. Obukhov and A. V. Timoshkin
gr-qc