Modeling, in particular with partial differential equations, plays an ever growing role in the applied sciences. Hence its mathematical understanding is an important issue for today's research. This book provides an introduction to three different topics in partial differential equations stemming from the applications for students and researchers with a basic background in this subject. Michel Chipot investigates equilibrium positions of several disks rolling on a wire. In particular, he discusses existence and uniqueness of, and the exact position for an equilibrium. Josselin Garnier...