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Propos sur l'interpretation de l'energie d'activation experimentale

Cas des decompositions endothermiques solide-gaz

Journal of Thermal Analysis and Calorimetry
Authors: G. Bertrand, M. Lallemant, and G. Watelle

The results from various investigations show that the experimental activation energy valueE e derived from the Arrhenius diagrams varies with pressure for endothermic decomposition reactions.

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Journal of Thermal Analysis and Calorimetry
Authors: G. Roussy, P. Colin, J. Thiebaut, G. Bertrand, and G. Watelle

The evaporation of a polar liquid at low pressure upon exposure to microwave radiation has been investigated. The conventional theories previously developed to describe the non-equilibrium conditions of the evaporating interface are found to be in poor agreement with the experimental results. It is possible to take into account the influence of microwave fields on the evaporating surface by modifying the expression for the entropy production. Another approach, based on the concept that microwaves would increase the pressure, has also been found to be satisfactory.

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Abstract

The adsorbed amounts of water vapor onto polyacrylic polymer (polymer ×10) were measured using a thermogravimetry method as a function of pressure at 298 and 313 K. The adsorption isotherms are categorized to type II isotherms by IUPAC classification leading to a hysteresis loop between adsorption and desorption branches. The current study was completed by the measurement of the adsorption heats at 298 K using a differential scanning calorimetry. The calorimetric curves showed two adsorption heats domains. These domains have been attributed to the adsorption of “equivalent monolayer” and the condensation of water between polymeric chains. The correlation of experimental data to some chosen theoretical models shows that the GAB model is the most adequate to describe water vapor sorption isotherms.

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