La Mer Partagée. La Méditerranée avant l'écriture, 7000-2000 avant Jésus-Christ.

C'est une formidable odyssée que nous offre Jean Guilaine dans cet ouvrage érudit et pourtant accessible, construit comme une encyclopédie thématique. Le titre choisi, la Mer Partagée, situe d'emblée la vision sous-jacente à l'entreprise : mer entre les terres d'Asie, d'Europe et d'Afrique, la Méditerranée est conçue comme épicentre civilisateur et comme caisse de résonance de processus dont le berceau continental est établi plus à l'est, dans le Croissant Fertile. La période considérée couvr..

La Mer Partagée. La Méditerranée avant l’écriture, 7000-2000 avant Jésus-Christ.

Jean Guilaine’s La Mer Partagée, conceived as a thematic encyclopedia, is an erudite but nonetheless inviting work, a formidable odyssey, the title of which (literally “The Shared Sea”) sets forth the author’s basic conception of the Mediterranean sea. It is epicenter to the civilizations of Asia, Europe and Africa and a sounding-board for processes taking place in the cradle of civilization further to the east, in the Fertile Crescent. The period under consideration span five millennia durin..

Optimal design of multi-channel microreactor for uniform residence time distribution

Multi-channel microreactors can be used for various applications that require chemical or electrochemical reactions in either liquid, gaseous or multi phase. For an optimal control of the chemical reactions, one key parameter for the design of such microreactors is the residence time distribution of the fluid, which should be as uniform as possible in the series of microchannels that make up the core of the reactor. Based on simplifying assumptions, an analytical model is proposed for optimizing the design of the collecting and distributing channels which supply the series of rectangular microchannels of the reactor, in the case of liquid flows. The accuracy of this analytical approach is discussed after comparison with CFD simulations and hybrid analytical-CFD calculations that allow an improved refinement of the meshing in the most complex zones of the flow. The analytical model is then extended to the case of microchannels with other cross-sections (trapezoidal or circular segment) and to gaseous flows, in the continuum and slip flow regimes. In the latter case, the model is based on second-order slip flow boundary conditions, and takes into account the compressibility as well as the rarefaction of the gas flow

CRPPM – Centre de recherche sur la pré- et protohistoire de la Méditerranée

Jessie Cauliez, ATER à l’Université Toulouse II-Le Mirail Réseaux d’échanges et de circulations, déplacements des biens, des idées et des personnes au néolithique Toutes les modifications caractérisant le Néolithique (essor des inégalités sociales, hiérarchisation et compétition entre les individus, réseaux d’échanges étoffés) traduisent un monde sous tension et régi aussi par la réciprocité. C’est précisément cette réciprocité qu’il s’est agi d’illustrer lors de ce séminaire au travers de si..

CRPPM – Centre de recherche sur la pré- et protohistoire de la Méditerranée

Jessie Cauliez, ATER à l’Université Toulouse II-Le Mirail Réseaux d’échanges et de circulations, déplacements des biens, des idées et des personnes au néolithique Toutes les modifications caractérisant le Néolithique (essor des inégalités sociales, hiérarchisation et compétition entre les individus, réseaux d’échanges étoffés) traduisent un monde sous tension et régi aussi par la réciprocité. C’est précisément cette réciprocité qu’il s’est agi d’illustrer lors de ce séminaire au travers de si..

Numerical study of the coupling between reaction and mass transfer for liquid-liquid slug flow in square microchannels

While the benefits of miniaturisation on processes have been widely demonstrated, its impact on microfluidics and local mechanisms such as mass transfer is still little understood. The aim of this work is to simulate coupling between reaction and mass transfer in microchannels for liquid-liquid slug flow. First, the extrapolation to confined flow of the classical model used to calculate interfacial mass fluxes in reactive infinite media was studied. This model consists in estimating transferred fluxes between two phases as a function of the enhancement factor E. Its expression depends on the model used to represent interfacial mass transfer. In infinite media, Lewis and Whitman’s stagnant film theory is generally preferred for its simplicity and its reliability. In the case of confined slug flow, the limitation of such a model to predict interfacial fluxes is highlighted. Secondly, the case of liquid-liquid competitive consecutive reactions in microchannels is considered. This work emphasizes the unfavourable impact of the length between droplets on selectivity. This is a direct consequence of mass transport mechanisms in microchannels

Design and optimization of electrochemical microreactors for continuous electrosynthesis

The study focuses on the design and construction, as well as the theoretical and experimental optimization of electrochemical filter press microreactors for the electrosynthesis of molecules with a high added value. The main characteristics of these devices are firstly a high-specific electrochemical area to increase conversion and selectivity, and secondly the shape and size of themicrochannels designed for a uniform residence time distribution of the fluid. A heat exchanger is integrated into the microstructured electrode to rapidly remove (or supply) the heat required in exo- or endothermic reactions. The microreactors designed are used to perform-specific electrosynthesis reactions such as thermodynamically unfavorable reactions (continuous NADH regeneration), or reactions with high enthalpy changes

Heat exchanger/reactors (HEX reactors): Concepts, technologies: State-of-the-art

Process intensification is a chemical engineering field which has truly emerged in the past few years and is currently rapidly growing. It consists in looking for safer operating conditions, lower waste in terms of costs and energy and higher productivity; and away to reach such objectives is to develop multifunctional devices such as heat exchanger/reactors for instance. This review is focused on the latter and makes a point on heat exchanger/reactors. After a brief presentation of requirements due to transposition from batch to continuous apparatuses, heat exchangers/reactors at industrial or pilot scales and their applications are described