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The knowledge of response times of active material is essential for their efficient use as actuators. In this paper the heating and cooling times of a shape memory alloy wire (NiTi) under a constant load are predicted by the integration of the corresponding heat equation. The comparison with a ‘fictitious’ material with the same material characteristics but without phase transformation shows that the response times are longer for the SMA (around 2.7 times for heating and 1.5 times for cooling). To cite this article: N. Chaillet et al., C. R. Mecanique 332 (2004). [Copyright &y& Elsevier]

The sequential iterative approach (SIA) scheme is the most efficient method for modelling reactive transport in porous media with the operator-splitting approach. A combination of finite discontinuous and finite mixed-hybrid elements is a powerful method for solving solute transport in porous media, but the use of this method for SIA scheme induces numerical difficulties. In this paper, a new method is developed to solve reactive transport by using both the SIA scheme and a combination of finite discontinuous and finite mixed elements. The proposed method is tested by modelling a column experiment. To cite this article: J. Carrayrou et al., C. R. Mecanique 331 (2003). [Copyright &y& Elsevier]

In this paper, we propose a model concerning the thermal transfers inside an emulsion of aqueous saline binary solution during the crystallization of the dispersed undercooled droplets. This model takes into account the erratic character owed to the probability of water crystallization, and to the probability of salt apparition. It also takes into account the phenomenon of the progressive crystallization owed to the thermodynamic balance in every drop. The model is based on the resolution of the energy equation with a heat source depending on the probability of crystallization of every drop. It has been applied to the scanning calorimetry in the case of an aqueous solution of sodium chloride dispersed within an industrial oil. The studied samples have a cylindrical shape of a few mm3 in volume. The good agreement between the numerical results and the experimental results permitted to validate the model, and therefore to better describe the thermal transfers in these dispersions. We determined the space–time distribution of the temperature and transformed part of every drop. An evaluation of the different exchange coefficients of involved in the model has also been brought. [Copyright &y& Elsevier]

This paper presents an investigation on laminar transient free convection along a vertical surface subjected to a periodical heat flux density. Numerical analysis show that heat transfer is improved when the over-heating period is inferior to the under-heating one and if the flow has reached its new steady state. To cite this article: T. de Lorenzo, C. R. Mecanique 330 (2002) 181–184. [Copyright &y& Elsevier]