Abstract: This chapter presents a collection of new examples taken from different branches of science. The first examples come from fluid dynamics, starting with the well-known model of viscous droplets spreading by gravity. It then covers topics relating to underground flows important in water management or oil recovery. Attention is given to models of plasma physics. The limits of particle models is also discussed.

Keywords: liquid film, thin films, immiscible fluids, boundary layer theory, plasma physics, particle models, PME,