Wind Tunnel Experiments on the Effects of Olives Mill Wastewaters Spray on the Reduction of the Entrainment of Sand by Wind

The degradation of physical characteristic of soils by wind erosion is one of major problem in the southern Tunisian arid regions. To find a remedy for these soils changes, studies were conducted, since many years, to reuse olives mill wastewaters, liquid waste produced in the process of olive oil extraction, like a simple and efficient practices for combating desertification. Wind-tunnel experiments were conducted on pre-treated soils with applied doses of 50 m3.ha-1, 100 m3.ha-1 and 200 m3.ha-1 next to an a witness soil sample in order to investigate the effect of the mulching of olives mill wastewaters on reduction of wind erosion. Sand samples were exposed to different wind speeds for 2 min. Shear velocities were deduced from the wind speed profiles and saltation of sand particles was recorded electronically with a saltiphone©.Within the 2-min test runs, changes in wind erosion aerodynamic parameters were detected. The aerodynamic roughness lenght, z0, and the threshold shear velocity, u*t, increase is proportional to the applied doses. The roughness lengths derived from the wind profile measurements measured over the various tested ranged from 1.78 E-04 and 3.92 E-04 m for 0 m3.ha-1 and 200 m3.ha-1, respectively. The results in wind tunnel tests on the soil treated with these different doses showed that u*t was raised from 8.65 m.s-1 to 12.15 m.s-1 for 50 m3.ha-1 and 200 m3.ha-1, respectively. These results strongly suggest that the mulching of olives mill wastewaters reduces soil erosion by wind

Quantification de l'érosion éolienne sur des surfaces anthropisées (simulations des flux en masse à l'échelle des zones arides Tunisiennes)

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Tunisian Case of Desert Valorisation for Promoter Enduring Development of Competence

Abstract: The aim of this study is to identify through economic, social and cultural indicators, the effects induced by a touristy activity development in the region of Tataouine (Southern Tunisian) in order to follow and measure the durability of this sector on this territory. Indeed, the Saharan tourism, based essentially on the patrimonial resources, the handicraft and all productions bound to the specific local resources exploitation, appears like a promoter sector carrier of dynamics susceptible to be transmitted to the whole economy and could be considered like an anchorage favourable point to an enduring development. The actors, both in public and private sector, survey showed that 78% of Tataouine region entrepreneurs proved their great satisfaction on the economic profitability of their projects. In addition, on the territorial integration of the enterprise and its contribution to the local economic channel, it was noticed that the impact on the local development is rather advantageous: on the one hand because the permanent or seasonal regular staff is employees of the region and on the other hand the supplies are, for the majority, local products. Nevertheless, the stakes in putting on tourism this delicate territory are considerable, especially when it was noticed that the Saharan tourism in Tunisia takes place on the base of generic benefits identical to those of the bathing model which could only increase the pressure on the Sahara

Ingénierie Dirigée par les Modèles pour une intégration efficace de UML et B

International audienceno abstrac

B4MSecure : une plateforme IDM pour la modélisation et la validation de politiques de sécurité en Systèmes d'Information (démo)

Session 10National audienceLa sécurité des Systèmes d'Information (SI) est un domaine où l'approche IDM (Ingénierie Dirigée par les modèles) peut se révéler fort utile. En effet, l'IDM prône l'utilisation de modèles tout au long du processus de développement en vue d'une séparation claire des règles métier et des contraintes intrinsèques à une technologie cible. Plusieurs approches dans le domaine de la sécurité ont d'ailleurs exploité cette piste, notamment MDA-Security, Model Driven Security (MDS), SecureUML, UMLSec, etc. Ces approches sont principalement dédiées à la modélisation, et la vérification, de règles de sécurité mais n'abordent pas le SI dans sa globalité. En effet, l'impact que le modèle fonctionnel peut avoir sur une politique de sécurité, et vice-versa, est très peu étudié dans la "littérature". C'est dans ce cadre que s'inscrit notre travail. Nous avons développé une plate-forme IDM dédiée à cet effet et qui permet de mener conjointement les activités de modélisation, de validation formelle et de test, et ce, aussi bien pour le modèle fonctionnel que pour les modèles de sécurité. Cette plate-forme exploite le paradigme IDM au moyen des outils Topcased, OAw et QVTo, et produit des spécifications formelles en B dont l'objectif est, d'une part, de valider par la preuve les différents modèles, et d'autre part de simuler des scénarios normaux et d'attaque au moyen d'outils d'animation de spécifications B

Infrastructure dirigée par les modèles pour une intégration adaptable et évolutive de UML et B

International audienceOne of the main objectives of software engineering is to develop well-structured and reliable systems. This explains the variety of approches for integrating formal and semi-formal methods ; especially those which produce B specifications from UML models. In this work, we try to unify these approaches in order to be able, on the one hand, to combine rules issued from these techniques, and on the other hand, to easily extend them. Our UML/B multi- modeling tool provides transformations from UML to B in an MDE architecture. We also proposed the notion of customizable rule which allows to adapt and extend existing approaches with respect to various abstraction levels: meta-model (M2), model (M1) or dual (M1/M2)

Approche transformationnelle à base de méta-modèles pour l'intégration de UML et de notations formelles

International audienceno abstrac

B4MSecure : A MDE platform for modeling and validation of Secure Information Systems (poster)

International audienceno abstrac

Particle size distributions of South Tunisian soils erodible by wind

International audience180 samples representative of surface soils erodible by wind were collected in South Tunisia to retrieve their grain size distribution. Dry sieving using 13 sieves was favour to preserve as much as possible the soil aggregates in their natural state. Two different methods were used to characterize the grain size distribution; the φ method of moments and the use of a combination of log-normal statistical functions. Both methods underline the ubiquitous and dominant presence of a very fine sand population (around 100 µm in diameter), very well sorted (σ=1,23) which corresponds to the grain size range for which the wind energy required for initiating the aeolian erosion is minimum. This clearly suggests that most of the soils in South Tunisia have the potential to be easily eroded by wind. However, in about 1/3 of the samples mainly those located in Dahars and in the vicinity of mountains, a secondary population of coarse grains (1500 µm in diameter) is also observed. This coarse mode could significantly reduce the wind erosion of the soils where it is present by covering a part of the surface and by limiting the efficiency of the wind transfer to the surface