First Passage Times and Breakthrough Curves Associated with Interfacial   Phenomena
  Advection and dispersion in highly heterogeneous environments involving interfacial discontinuities in the corresponding drift and dispersion rates are described through disparate examples from the physical and biological sciences. A mathematical framework is formulated to address specific empirical phenomena involving first passage time and occupation time functionals observed in relation to the interfacial parameters. 
Edward C. Waymire, Thilanka A. Appuhamillage, Vrushali A. Bokil,   Enrique A. Thomann, Brian D. Wood
math.PR cond-mat.stat-mech