In September 2000, the University of Bayreuth, Germany, hosted the Fourth International Meeting on Thermodi?usion (IMT4). TheIMTconferenceswerebornfromtheideaofbringingtogetherresearchers in the ?eld of thermodi?usion. Under the auspices of the European Group of Research in Thermodi?usion(EGRT)theconferenceseriesstartedin1994with IMT1 in Toulouse and has been continued every other year with IMT2 (Pau, 1996), IMT3 (Mons, 1998), and IMT4 (Bayreuth, 2000). The next conference, IMT5, will be held in 2002 in Lyngby, Denmark. Thermodi?usion,alsocalledthermaldi?usionortheLudwig-Sorete?ect,- scribes the coupling between a temperature gradient and a resulting mass ?ux. Although the e?ect was already discovered in the 19th century by Ludwig and Soret, it has gained growing interest during the last years due to improved - perimentaltechniqueslikestate-of-the-artthermogravitationalcolumns,modern opticalmethods,?owchannels,andmicrogravityexperiments,tomentiononlya few. We are still far from a detailed microscopic picture, but analytical theories have been improved and the availability of fast computers and e?cient al- rithmsfornonequilibriummoleculardynamicssimulationshasprovidedvaluable input from the theoretical side. TheIMTconferencescoverallaspectsofthermodi?usionfromfundamentals to new applications. Traditionally, the focus has been on the ?uid state, ra- ing from mixtures of simple liquids to more complex systems such as critical mixtures, electrolytes, polymers, colloidal dispersions, or magnetic ?uids. IMT4 tried to widen the scope by including a plenary lecture about thermodi?usion in ionic solids. Scienti?c input comes from diverse disciplines such as physics, chemistry, engineering, and geophysics. Sadly, Leo Kempers passed away while this book was being prepared. Many ofushavelostafriendandrespectedcolleague.Hismanuscripthasbeenbrought into its ?nal state by A. Shapiro, whom we want to thank here.

Thermodiffusion describes the coupling between a temperature gradient and a resulting mass flux. Traditionally, the focus has been on simple fluids, and it is now extending to more complex systems such as electrolytes, polymers, colloidal dispersions and magnetic fluids. This book widens the scope even further by including applications in ionic solids. Written as a set of tutorial reviews, it will be useful to experts, nonspecialist researchers and postgraduate students alike.

In September 2000, the University of Bayreuth, Germany, hosted the Fourth International Meeting on Thermodi?usion (IMT4). TheIMTconferenceswerebornfromtheideaofbringingtogetherresearchers in the ?eld of thermodi?usion. Under the auspices of the European Group of Research in Thermodi?usion(EGRT)theconferenceseriesstartedin1994with IMT1 in Toulouse and has been continued every other year with IMT2 (Pau, 1996), IMT3 (Mons, 1998), and IMT4 (Bayreuth, 2000). The next conference, IMT5, will be held in 2002 in Lyngby, Denmark. Thermodi?usion,alsocalledthermaldi?usionortheLudwig-Sorete?ect,- scribes the coupling between a temperature gradient and a resulting mass ?ux. Although the e?ect was already discovered in the 19th century by Ludwig and Soret, it has gained growing interest during the last years due to improved - perimentaltechniqueslikestate-of-the-artthermogravitationalcolumns,modern opticalmethods,?owchannels,andmicrogravityexperiments,tomentiononlya few. We are still far from a detailed microscopic picture, but analytical theories have been improved and the availability of fast computers and e?cient al- rithmsfornonequilibriummoleculardynamicssimulationshasprovidedvaluable input from the theoretical side. TheIMTconferencescoverallaspectsofthermodi?usionfromfundamentals to new applications. Traditionally, the focus has been on the ?uid state, ra- ing from mixtures of simple liquids to more complex systems such as critical mixtures, electrolytes, polymers, colloidal dispersions, or magnetic ?uids. IMT4 tried to widen the scope by including a plenary lecture about thermodi?usion in ionic solids. Scienti?c input comes from diverse disciplines such as physics, chemistry, engineering, and geophysics. Sadly, Leo Kempers passed away while this book was being prepared. Many ofushavelostafriendandrespectedcolleague.Hismanuscripthasbeenbrought into its ?nal state by A. Shapiro, whom we want to thank here.

This book deals with density, temperature, velocity and concentration fluctuations in fluids and fluid mixtures. The book first reviews thermal fluctuations in equilibrium fluids on the basis of fluctuating hydrodynamics. It then shows how the method of fluctuating hydrodynamics can be extended to deal with hydrodynamic fluctuations when the system is in a stationary nonequilibrium state. In contrast to equilibrium fluids where the fluctuations are generally short ranged unless the system is close to a critical point, fluctuations in nonequilibrium fluids are always long-ranged encompassing the entire system. The book provides the first comprehensive treatment of fluctuations in fluids and fluid mixtures brought out of equilibrium by the imposition of a temperature and concentration gradient but that are still in a macroscopically quiescent state. By incorporating appropriate boundary conditions in the case of fluid layers, it is shown how fluctuating hydrodynamics affects the fluctuations close to the onset of convection. Experimental techniques of light scattering and shadowgraphy for measuring nonequilibrium fluctuations are elucidated and the experimental results thus far reported in the literature are reviewed.· Systematic exposition of fluctuating hydrodynamics and its applications· First book on nonequilibrium fluctuations in fluids· Fluctuating Boussinesq equations and nonequilibrium fluids· Fluid layers and onset of convection· Rayleigh scattering and Brillouin scattering in fluids· Shadowgraph technique for measuring fluctuations· Fluctuations near hydrodynamic instabilities

Fluid and flow problems in porous media have attracted the attention of industrialists, engineers and scientists from varying disciplines, such as chemical, environmental, and mechanical engineering, geothermal physics and food science. There has been a increasing interest in heat and fluid flows through porous media, making this book a timely and appropriate resource.Each chapter is systematically detailed to be easily grasped by a research worker with basic knowledge of fluid mechanics, heat transfer and computational and experimental methods. At the same time, the readers will be informed of the most recent research literature in the field, giving it dual usage as both a post-grad text book and professional reference.Written by the recent directors of the NATO Advanced Study Institute session on 'Emerging Technologies and Techniques in Porous Media' (June 2003), this book is a timely and essential reference for scientists and engineers within a variety of fields.

The purpose of this book is to encourage the use of non-equilibrium thermodynamics to describe transport in complex, heterogeneous media. With large coupling effects between the transport of heat, mass, charge and chemical reactions at surfaces, it is important to know how one should properly integrate across systems where different phases are in contact. No other book gives a prescription of how to set up flux equations for transports across heterogeneous systems.The authors apply the thermodynamic description in terms of excess densities, developed by Gibbs for equilibrium, to non-equilibrium systems. The treatment is restricted to transport into and through the surface. Using local equilibrium together with the balance equations for the surface, expressions for the excess entropy production of the surface and of the contact line are derived. Many examples are given to illustrate how the theory can be applied to coupled transport of mass, heat, charge and chemical reactions; in phase transitions, at electrode surfaces and in fuel cells. Molecular simulations and analytical studies are used to add insight.