Vers une valorisation du savoir-faire local des oasis : cas du jus de dattes Tassabount au Maroc

Introduction. Les oasis marocaines sont réputées pour le savoir-faire ingénieux de leurs habitants en matière de gestion et de préservation des ressources naturelles. La datte, principal produit des oasis, bénéficie amplement de cette ingéniosité qui connaît, de nos jours, une régression et un manque de valorisation. Notre étude a eu pour objectif d'archiver et d'analyser le savoir-faire de la transformation des dattes en jus, localement appelé Tassabount, et d'en proposer un mode de valorisation. Matériel et méthodes. La méthodologie employée pour le travail d'archivage et d'analyse des connaissances locales de transformation des dattes en jus a été basé sur une approche participative impliquant une centaine de femmes oasiennes de la vallée du Drâa (Maroc). Résultats et discussion. Notre étude a mis en évidence une pratique ingénieuse dans la transformation locale des dattes en jus. Ce savoirfaire, développé par les femmes oasiennes, est étroitement lié à la diversité génétique du palmier dattier (variétés et hybrides). En outre, le Tassabount est identifié comme produit prometteur à valoriser, en misant sur ses qualités organoleptiques et ses vertus thérapeutiques. Par ailleurs, la description et l'analyse du procédé familial de préparation du Tassabount ont permis d'identifier des voies possibles d'amélioration pour son élaboration et sa stabilisation en vue de son transfert à des entreprises artisanales et/ou industrielles. (Résumé d'auteur

Study of the reactivity of chalcogen hexafluorides with graphite

International audienceThe intercalation reaction of chalcogen hexafluorides EF 6 (E = S, Se, Te) with graphite was investigated. It occured only under a fluorine atmosphere and first stage intercalation compounds were obtained with TeF6 or SeF6, as well as a partial graphite fluorination. SF6 did not intercalate but catalyzed the complete fluorination of graphite. All compounds were characterized by X-ray diffraction, thermogravimetric analysis, infrared and 19F NMR spectroscopies. Entities, such as TeF6 and SeF6 were identified. Others, such as EF7 - , EF8 2- ,. . ., and possible SeFn polymeric forms could exist. In all cases, the presence of fluorinated graphite was found

The prediction of the inside temperature and relative humidity of a greenhouse using ANN method with limited environmental and meteorological data

In this paper, the prediction of the internal temperature (Tin) and relative humidity (Rhin) of a greenhouse located near Agadir, Morocco using artificial neural net-work (ANN) as machine learning method. First, an analyze of correlations be-tween inputs and outputs is studied in order to select the adequate input parameters. External temperature, relative humidity and solar radiations were the parameters that have the highest correlation coefficient with the outputs. They are thus selected as the only input parameters. The prediction of Tin and Rhin with the previously cited inputs gives a perfect coefficient of correlation (R=0.996). The aim of this study is to use only one measured input parameter (external temperature) and eliminate the two environmental parameters (relative humidity and solar radiation), by introducing the factor of time as input of the ANN model. Results were very satisfying and 20 neurons was sufficient to reach a correlation of about 0.98

Computational study of thermal performance of an unheated canarian-type greenhouse: influence of the opening configurations on airflow and climate patterns at the crop level

International audienceThe increasing cost of electricity often drives the famers of the countries of the southern shore of the Mediterranean, to adopt the natural ventilation in order to provide greenhouse aeration. The roof and sidewall vents are opened to allow the excess heat to escape and cooler outside air to enter during daytime. During night time, these openings are used mainly to regulate the excess humidity in greenhouse which causes damage on plants due to the development of Botrytis cinerea. This paper presents a computational fluid dynamic (CFD) comparative study of the effect of these roof and sidewall ventilation openings on airflow circulation and diurnal and nocturnal greenhouse climate distribution to assess their effect. The investigation was conducted in a one hectare canarian-type greenhouse, the most widely used in Morocco, with a mature tomato crop. The simulations were performed with the CFD model based on solving partial differential equations, which represent conservation laws for the mass, momentum, and energy, using CFD finite volume method (FVM). This CFD model takes into account the virtual crop as a porous medium using the Darcy-Forchheimer model restricted to its inertial terms. Simulation results show that opening configurations strongly affects the airflow circulation under the studied greenhouse, which can generate a heterogeneous climate at the canopy level, especially during daytime. Results have illustrated also that there is a reverse flow from the leeward end to windward end part of the greenhouse at the crop level. Closing the north-south sidewall ventilation openings contributes significantly to the inside air velocity increase which can decrease the diurnal air temperature at the crop level. Conversely, during night-time, climate distribution at the crop level is homogeneous on the whole greenhouse

Canary greenhouse CFD nocturnal climate simulation

The aim of this paper is to predict in details the distributed nocturnal climate inside a one hectare Moroccan canary type tomato-greenhouse equipped with continuous roof and sidewalls ventilation openings with fine insect screens, by means of 3D CFD (Computational Fluid Dynamics) simulations by using a commercial Software package CFD2000 based on the finite volumes method to solve the mass, momentum and energy conservation equations. The turbulent transfers were described by a k-ε model. Likewise, the dynamic influences of insect screens and tomato crop on airflow movement were modeled by means of the concept of porous medium with the Boussinesq assumption. Atmospheric radiations contribution was included in the model by customising the plastic roof cover temperature deducted from its energy balance. Also, the CFD code was customized in order to simulate in each element of the crop cover the sensible and latent heat exchanges between the greenhouse air and tomato crop. Simulations were carried out with a wind prevailing direction perpendicular to the roof openings (west-east direction). Simulations were later validated with respect to temperature and specific humidity field measurements inside the experimental greenhouse. Also, the model was verified respect to global sensible and latent heat transfers. Results show that, generally, greenhouse nocturnal climate distribution is homogeneous along the studies greenhouse area. The insect proof significantly reduced inside airflow wind speed. But there is no significant effect on the inside air temperature and specific humidity respect to outside