Jean-Claude Bénet
University of Montpellier
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Featured researches published by Jean-Claude Bénet.
Powder Technology | 1999
Y. Haddad; F Mabille; A. Mermet; Joël Abecassis; Jean-Claude Bénet
Abstract The suitability of wheat grains for milling varies widely according to a large number of factors. Among these factors, kernel hardness and vitreousness contribute to a considerable extent to the milling behaviour of wheats, yield of mill streams and flour size distribution. An original method has been developed to measure the rheological properties of cereal grain endosperm. The failure stress depends on both hardness and vitreousness of endosperm whereas Youngs modulus appears to be related above all to hardness. In addition, depending on the kernel texture, the mode of fracture of the grain may be either fragile or ductile. The results of these rheological measurements appear to be in good agreement with the milling behaviour of the grains.
Cereal Chemistry | 1998
Y. Haddad; Jean-Claude Bénet; Joël Abecassis
ABSTRACT A rapid, simple method was developed to prepare small, parallelepipedal test samples of endosperm of wheat, corn, and rice grains. Compression tests performed on endosperm samples revealed the following mechanical properties: modulus of elasticity (E, GPa), breaking stress (σrup, MPa), and maximum breaking strain (erup, %). All tests were performed on several endosperm test samples of each cereal species. The results displayed good repeatability and several significant differences in the mechanical behavior of different endosperm structures, especially among soft, hard, and durum wheats. Rice and corn endosperm displayed mechanical behavior similar to that of durum wheat endosperm. The method proposed appears to be sufficiently sensitive and repeatable for studying the incidence of hardness and vitreousness of cereal grain endosperm in relation to its suitability for milling.
Journal of Non-Equilibrium Thermodynamics | 2009
Jean-Claude Bénet; Anne-Laure Lozano; Fabien Cherblanc; Bruno Cousin
Abstract The phenomenological relation of non-equilibrium liquid–gas phase change in a porous medium is described at the macroscopic level using the difference in chemical potentials between the liquid and its vapor. The experiments conducted consisted in lowering the partial pressure of water vapor in the pores of a hygroscopic soil and analyzing the return to equilibrium by two measurements: the macroscopic temperature and the partial pressure of vapor. The central hypothesis of the study is that the characteristic time associated with thermal equilibrium is much lower than the characteristic time associated with mass transfers. From these measurements, it is possible to determine the relation that links phase change rate to the logarithm of the ratio of partial vapor pressure divided by the equilibrium pressure (RH). The representation of this relation according to RH reveals two regimes in the return to equilibrium. The characteristics of these regimes are analyzed according to water content, temperature, and total gas phase pressure.
Environmental Science & Technology | 2010
Samuel Ouoba; Fabien Cherblanc; Bruno Cousin; Jean-Claude Bénet
Sorption from the vapor phase is an important factor controlling the transport of volatile organic compounds (VOCs) in the vadose zone. Therefore, an accurate description of sorption behavior is essential to predict the ultimate fate of contaminants. Several measurement techniques are available in the case of water, however, when dealing with VOCs, the determination of sorption characteristics generally relies on gas chromatography. To avoid some drawbacks associated with this technology, we propose a new method to determine the sorption isotherm of any liquid compounds adsorbed in a soil. This method is based on standard and costless transducers (gas pressure, temperature) leading to a simple and transportable experimental device. A numerical estimation underlines the good accuracy and this technique is validated on two examples. Finally, this method is applied to determine the sorption isotherm of three liquid compounds (water, heptane, and trichloroethylene) in a clayey soil.
Archive | 2005
Ali Chammari; Bétaboalé Naon; Fabien Cherblanc; Jean-Claude Bénet
The description of water transport in soil at low water content proposed is based on the idea that liquid/gas phase change occurs with vapor diffusion in the gas phase. The phase change modelisation introduces a phenomenological coefficient characterized through an experimental investigation done on smallscale soil samples. Then, numerical simulations are compared to experimental drying kinetics carried out on macroscopic soil samples. Good agreement is obtained, which strengthens the hypothesis of transport in the gas phase associated with a nonequilibrium liquid/gas phase change.
European Journal of Environmental and Civil Engineering | 2013
Bétaboalé Naon; Jean-Claude Bénet; Bruno Cousin; Fabien Cherblanc; Ali Chammari
This article presents an experimental and theoretical study of volatile organic compounds volatilisation in soil during a decontamination process by vapour extraction or venting. A phase change law is proposed in the case of a sandy-silty soil when the convective gaseous phase is vapour charged. A simple experimental method for analysing the phase change is presented. Finally, an efficiency coefficient is introduced to quantify the contribution of airflow velocity on venting. Cet article présente une étude expérimentale et théorique de la volatilisation d’un COV dans un sol soumis à une décontamination par ventilation. On propose une relation de changement de phase dans le cas convectif pour un limon sableux hygroscopique lorsque l’air en mouvement est chargé de vapeur de COV. Une méthode expérimentale simple d’analyse du changement de phase est proposée. Finalement un coefficient d’efficacité est introduit pour quantifier l’influence de la vitesse de l’air sur l’efficacité de la ventilation.
Journal of Chemistry | 2015
Samuel Ouoba; Fabien Cherblanc; Jean Koulidiati; Jean-Claude Bénet
This paper presents a new mechanical method to determine Henry’s law constant (HLC) of a volatile organic compound (VOC). This method is an extension of the one proposed by Ouoba et al. (2010) to determine the water activity in porous media. This work focuses on TCE and aims at characterizing its liquid-vapor equilibrium in various cases in the form of a pure liquid phase or dissolved in an aqueous solution, adsorbed or not in a natural soil. A liquid phase is disposed in a closed chamber whose volume can be incrementally increased. The recording of the total gas pressure leads to evaluating the vapor partial pressure of a volatile compound even in the case of an aqueous solution. This method has been validated using various aqueous solutions of TCE and the HLC obtained is in agreement with the literature. Then, the validity of Henry’s law has been asserted in the case of an aqueous solution of TCE adsorbed in a hygroscopic soil. Indeed, a linear relation between the vapor partial pressure of TCE and its concentration has been obtained while the HLC is about 16% lower. This result highlights the influence of adsorption phenomena on vapor/liquid equilibrium.
Transport in Porous Media | 2014
M. Anoua; Alejandra Ramirez-Martinez; Fabien Cherblanc; Jean-Claude Bénet
We consider a complex medium composed of finely intertwined micro-skeletons and micro-compartments where water transfer can occur. In these media, at low moisture content, water pressure measurement is not longer possible. Mass transfer is then expressed in terms of chemical potential gradient. The assumption of local thermodynamic equilibrium, resulting in the uniformity of water chemical potential in all microstructures, is essential to define a sorption isotherm reflecting the relationship between water activity and average moisture content. In this case, it is also possible to describe water transfer by using the chemical potential gradient. Radial water transfer in wood is examined using a destructive method for calculating water flux and chemical potential gradient at the same position and at the same time. We deduce the variation of transport coefficient as a function of moisture content.
Transport in Porous Media | 2015
Samuel Ouoba; Tizane Daho; Fabien Cherblanc; Jean Koulidiati; Jean-Claude Bénet
This paper presents a new method to determine the evaporation coefficient of trichloroethylene using a new experimental device called “activity-meter”. This device and the associated method have been developed in the Laboratory of Mechanical Engineering of the University of Montpellier 2 (France). The influence of diffusion on the vapor pressure of trichloroethylene and the influence of temperature at the liquid–gas interface were first determined. The results show that diffusion phenomena have no influence on the vapor pressure of trichloroethylene beyond 400 s of experimental time and the temperature is almost constant during experiments. Thus, in order to take into account the effects that are only due to the variation of partial pressure of trichloroethylene at the liquid–gas interface, the time interval used is between 400 s and the time required to reach equilibrium. The influence of pressure and temperature on the evaporation coefficient of pure trichloroethylene in an arid soil was then highlighted. The results show that the evaporation coefficient of trichloroethylene decreases with total vapor pressure but increases with temperature. A comparative study on evaporation coefficients conducted on water, heptane, and trichloroethylene shows that our results are in good agreement with results on volatility.
Archive | 2005
Jean-Yves Delenne; Moulay Saïd El Youssoufi; Jean-Claude Bénet
This paper deals with an experimental and numerical investigation of mechanical behaviour and rupture of cohesive granular media. Cohesion is characterised experimentally, from a reference medium made of aluminium cylinders glued between them with an epoxy resin. For each type of loading (tension/compression, shearing and couple), experiments give a force-displacement relation, as well as a failure criterion. This local mechanical behaviour is then introduced in a numerical code based on a discrete element method. Finally, from a comparison between numerical and experimental compression test on macroscopic granular samples, we present a validation of the mechanical approach. The approach presented here enables to analyse the localisation of the deformation as well as the initiation and propagation of fractures in granular media.