This volume focuses on modeling processes for which transport is one of the most complicated components, requiring different transport models in each region. The authors apply questions to a wide variety of application areas, such as semiconductors, plasmas, fluids, chemically reactive gases, etc.

IMA Volumes 135: Transport in Transition Regimes and 136: Dispersive Transport Equations and Multiscale Models focus on the modeling of processes for which transport is one of the most complicated components. This includes processes that involve a wdie range of length scales over different spatio-temporal regions of the problem, ranging from the order of mean-free paths to many times this scale. Consequently, effective modeling techniques require different transport models in each region. The first issue is that of finding efficient simulations techniques, since a fully resolved kinetic simulation is often impractical. One therefore develops homogenization, stochastic, or moment based subgrid models. Another issue is to quantify the discrepancy between macroscopic models and the underlying kinetic description, especially when dispersive effects become macroscopic, for example due to quantum effects in semiconductors and superfluids. These two volumes address these questions in relation to a wide variety of application areas, such as semiconductors, plasmas, fluids, chemically reactive gases, etc.

Downscaling of semiconductor devices, which is now reaching the nanometer scale, makes it mandatory for us to understand the quantum phenomena - volvedinchargetransport.Indeed,fornanoscaledevices,thequantumnature of electrons cannot be neglected. In fact, it underlies the operation of an increasing number of devices. Unlike classical transport, the intuition of the physicistandtheengineerisbecominginsu?cientforpredictingthenatureof device operation in the quantum context-the need for su?ciently accurate and numerically tractable models represents an outstanding challenge in which applied mathematics can play an important role. TheCIMESession"QuantumTransport:Modelling,AnalysisandAsy- totics", which took place in Cetraro (Cosenza), Italy, from September 11 to September 16, 2006, was intended both to present an overview of up-to-date mathematical problems in this ?eld and to provide the audience with te- niques borrowed from other ?elds of application. It was attended by about 50 scientists and researchers, coming from d- ferent countries. The list of participants is included at the end of this book. The school was structured into four courses: ' * Gr' egoire Allaire (Ecole Polytechnique, Palaiseau, France) Periodic - mogeneization and E?ective MassTheorems for theSchr. odinger Equation. * AntonArnold(TechnischeUniversit. at,Vienna)MathematicalProperties of Quantum Evolution Equations. * Pierre Degond (Universit' e Paul Sabatier and CNRS, Toulouse, France) Quantum Hydrodynamic and Di?usion Models Derived from the Entropy Principle. * Thomas Yizhao Hou (Caltech, Los Angeles, USA) Multiscale Com- tations for Flow and Transport in Heterogeneous Media. This book contains the texts of the four series of lectures presented at the Summer School. Here follows a brief description of the subjects of these courses.