Moisture sorption isotherms and thermodynamic properties of Asteriscus graveolens leaves

Asteriscus graveolens is a medicinal and aromatic plant which has been used to treat several diseases.Moisture equilibrium data of the plant leaves were determined by using the gravimetric static method at 30°C, 40°C, and 50°C for water activity

Etude théorique et expérimentale du séchage solaire des feuilles de la menthe verte (Mentha viridis)

Les plantes médicinales et aromatiques et en particulier les feuilles de la menthe verte ont beaucoup d\u27importance pour la pharmacopée, la parfumerie, et la liquoristerie. Afin de développer un code de calcul permettant de simuler le séchage solaire en convection forcée de cette plante, une détermination expérimentale des isothermes de sorption a été menée. Les courbes de sorption ainsi obtenues sont ensuite approchées par des modèles empiriques et semi-empiriques utilisables dans un modèle numérique d\u27un séchoir. Une autre étude expérimentale est consacrée à la détermination des cinétiques de séchage dans des conditions contrôlables ainsi que dans un séchoir solaire. Les courbes de perte de masse et l\u27influence de la température et de la vitesse de l\u27air asséchant sont étudiées dans le but de déterminer la courbe caractéristique de séchage (CCS), et par conséquent la corrélation empirique exprimant la vitesse de séchage de la menthe verte étudiée. Par la suite les deux corrélations ainsi obtenues sont introduites dans un programme écrit en Fortran afin de valider les résultats expérimentaux de la teneur en eau et la vitesse de séchage en fonction du temps pour les modes de séchage et d\u27étudier l\u27influence de la température, du débit, de l\u27hygrométrie de l\u27air asséchant et de la masse initiale des feuilles de menthe. Afin de dimensionner notre séchoir une étude paramétrique basée sur la technique des plans d\u27expérience est menée. Le modèle développé dans ce travail permettra de dimensionner un séchoir et d\u27étudier son fonctionnement dans le cas d\u27utilisation avec un capteur solaire afin de définir les conditions optimales de séchage

Thermodynamic properties and moisture sorption isotherms of Matricaria pubescens from Algerian Sahara

Experimental adsorption and desorption behavior of Matricaria pubescens was determined by using the gravimetric static method at 30, 40 and 50 °C, for water activity ranging from 0.057 to 0.898. Experimental data were compared with eight widely recommended sorption models (Caurie, BET, Henderson-Thomson, Smith, Halsey, Oswin, Peleg, and Adam and Shove) in literature. Peleg and Halsey models were found to be the most suitable for describing sorption isotherm curves. The net isosteric heats of sorption were also calculated by using the Clausius-Clapeyron equation

Mathematical Modeling of Moisture Sorption Isotherms and Determination of Isosteric Heats of Sorption of Ziziphus Leaves

Desorption and adsorption equilibrium moisture isotherms of Ziziphus spina-christi leaves were determined using the gravimetricstatic method at 30, 40, and 50 ∘ C for water activity ( ) ranging from 0.057 to 0.898. At a given , the results show that the moisture content decreases with increasing temperature. A hysteresis effect was observed. The experimental data of sorption were fitted by eight models (GAB, BET, Henderson-Thompson, modified-Chung Pfost, Halsey, Oswin, Peleg, and Adam and Shove). After evaluating the models according to several criteria, the Peleg and Oswin models were found to be the most suitable for describing the sorption curves. The net isosteric heats of desorption and adsorption of Ziziphus spina-christi leaves were calculated by applying the Clausius-Clapeyron equation to the sorption isotherms and an expression for predicting these thermodynamic properties was given

Mathematical Modeling of Moisture Sorption Isotherms and Determination of Isosteric Heats of Sorption of Ziziphus Leaves

Desorption and adsorption equilibrium moisture isotherms of Ziziphus spina-christi leaves were determined using the gravimetric-static method at 30, 40, and 50°C for water activity (aw) ranging from 0.057 to 0.898. At a given aw, the results show that the moisture content decreases with increasing temperature. A hysteresis effect was observed. The experimental data of sorption were fitted by eight models (GAB, BET, Henderson-Thompson, modified-Chung Pfost, Halsey, Oswin, Peleg, and Adam and Shove). After evaluating the models according to several criteria, the Peleg and Oswin models were found to be the most suitable for describing the sorption curves. The net isosteric heats of desorption and adsorption of Ziziphus spina-christi leaves were calculated by applying the Clausius-Clapeyron equation to the sorption isotherms and an expression for predicting these thermodynamic properties was given