Nonlinear partial differential equations abound in modern physics. The problems arising in these fields lead to fascinating questions and, at the same time, progress in understanding the mathematical structures is of great importance to the models. Nevertheless, activity in one of the approaches is not always sufficiently in touch with developments in the other field. The book presents the joint efforts of mathematicians and physicists involved in modelling reactive flows, in particular superconductivity and superfluidity. Certain contributions are fundamental to an understanding of such cutting-edge research topics as rotating Bose-Einstein condensates, Kolmogorov-Zakharov solutions for weak turbulence equations, and the propagation of fronts in heterogeneous media.

CARGESE INSTITUfE ON DISORDER AND MIXING Convection, diffusion and reaction are the three basic mechanisms in physico-chemical hydrodynamics and chemical engineering. Both convective and diffusive processes are strongly influenced by the effect of disorder of granular matter in porous media, suspensions, fluidized beds or/and by the randomness caused in turbulent flow field. This book has been initiated by a NATO summer institute held in Cargese (Corsica, FRANCE) from June 15 th to 27 th 1987 . Its aim was to associate statistical physicists, fluid mechanicians and specialists of chemical engineering on the problems of the relation between disorder and mixing and, in this respect, this is a " premiere ." This book is made of chapters based on lectures given in the meeting. However we have paid a considerable attention to harmonize the contents and styles of chapters made by scientists trained in different communities and using different languages and techniques to describe similar problems. The Prelude by the editors of the book introduces the different points and is a biased view of some of the important and most active aspects of the subjects developed. We wish to thank all contributors and students of the institute who gave the style of the present interdisciplinary approach. We also greatly thank Elisabeth Charlaix who has shared with us the scientific and practical organisation of the institute, and Marie-France Hanseler for her technical support.

We experience elasticity everywhere in daily life: in the straightening or curling of hairs, the irreversible deformations of car bodies after a crash, or the bouncing of elastic balls in ping-pong or soccer. The theory of elasticity is essential to the recent developments of applied and fundamental science, such as the bio-mechanics of DNA filaments and other macro-molecules, and the animation of virtual characters in computer graphics and materials science. In this book, the emphasis is on the elasticity of thin bodies (plates, shells, rods) in connection with geometry. It covers such topics as the mechanics of hairs (curled and straight), the buckling instabilities of stressed plates, including folds and conical points appearing at larger stresses, the geometric rigidity of elastic shells, and the delamination of thin compressed films. It applies general methods of classical analysis, including advanced nonlinear aspects (bifurcation theory, boundary layer analysis), to derive detailed, fully explicit solutions to specific problems. These theoretical concepts are discussed in connection with experiments. The book is self-contained. Mathematical prerequisites are vector analysis and differential equations. The book can serve as a concrete introduction to nonlinear methods in analysis.

Nonlinear partial differential equations abound in modern physics. The problems arising in these fields lead to fascinating questions and, at the same time, progress in understanding the mathematical structures is of great importance to the models. Nevertheless, activity in one of the approaches is not always sufficiently in touch with developments in the other field. The book presents the joint efforts of mathematicians and physicists involved in modelling reactive flows, in particular superconductivity and superfluidity. Certain contributions are fundamental to an understanding of such cutting-edge research topics as rotating Bose-Einstein condensates, Kolmogorov-Zakharov solutions for weak turbulence equations, and the propagation of fronts in heterogeneous media.

CARGESE INSTITUfE ON DISORDER AND MIXING Convection, diffusion and reaction are the three basic mechanisms in physico-chemical hydrodynamics and chemical engineering. Both convective and diffusive processes are strongly influenced by the effect of disorder of granular matter in porous media, suspensions, fluidized beds or/and by the randomness caused in turbulent flow field. This book has been initiated by a NATO summer institute held in Cargese (Corsica, FRANCE) from June 15 th to 27 th 1987 . Its aim was to associate statistical physicists, fluid mechanicians and specialists of chemical engineering on the problems of the relation between disorder and mixing and, in this respect, this is a " premiere ." This book is made of chapters based on lectures given in the meeting. However we have paid a considerable attention to harmonize the contents and styles of chapters made by scientists trained in different communities and using different languages and techniques to describe similar problems. The Prelude by the editors of the book introduces the different points and is a biased view of some of the important and most active aspects of the subjects developed. We wish to thank all contributors and students of the institute who gave the style of the present interdisciplinary approach. We also greatly thank Elisabeth Charlaix who has shared with us the scientific and practical organisation of the institute, and Marie-France Hanseler for her technical support.

This book provides an introduction to topics in non-equilibrium quantum statistical physics for both mathematicians and theoretical physicists. The first part introduces a kinetic equation, of Kolmogorov type, which is needed to describe an isolated atom (actually, in experiments, an ion) under the effect of a classical pumping electromagnetic field which keeps the atom in its excited state(s) together with the random emission of fluorescence photons which put it back into its ground state. The quantum kinetic theory developed in the second part is an extension of Boltzmann's classical (non-quantum) kinetic theory of a dilute gas of quantum bosons. This is the source of many interesting fundamental questions, particularly because, if the temperature is low enough, such a gas is known to have at equilibrium a transition, the Bose-Einstein transition, where a finite portion of the particles stay in the quantum ground state. An important question considered is how a Bose gas condensate develops in time if its energy is initially low enough.

We experience elasticity everywhere in daily life: in the straightening or curling of hairs, the irreversible deformations of car bodies after a crash, or the bouncing of elastic balls in ping-pong or soccer. The theory of elasticity is essential to the recent developments of applied and fundamental science, such as the bio-mechanics of DNA filaments and other macro-molecules, and the animation of virtual characters in computer graphics and materials science. In this book, the emphasis is on the elasticity of thin bodies (plates, shells, rods) in connection with geometry. It covers such topics as the mechanics of hairs (curled and straight), the buckling instabilities of stressed plates, including folds and conical points appearing at larger stresses, the geometric rigidity of elastic shells, and the delamination of thin compressed films. It applies general methods of classical analysis, including advanced nonlinear aspects (bifurcation theory, boundary layer analysis), to derive detailed, fully explicit solutions to specific problems. These theoretical concepts are discussed in connection with experiments. Mathematical prerequisites are vector analysis and differential equations. The book can serve as a concrete introduction to nonlinear methods in analysis.