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Tunis, Tunisia

Chaaben A.B.,Research Unit RME | Andoulsi R.,LaNSE | Sellami A.,ESSTT
Journal of Applied Fluid Mechanics | Year: 2011

The most widely used desalination processes are based on membrane separation via reverse osmosis (RO) which has become an important process for desalting seawater and cleaning brackish water. The use of these processes requires an efficient control system. Consequently, it is necessary to establish a dynamic model of the system with experimental validation. This paper deals with a new modelling approach of a small photovoltaic reverse osmosis (PV-RO) desalination unit. The proposed model considers the unit as a Multi Input Multi Output (MIMO) process. The relations between the output variables and the input variables are given by the use of empirical transfer matrix. A state model of the unit is also given. Some experimental results are presented to validate the proposed model. As result, the obtained unit model can be easily used for a process control loop implementation in order to assure an optimum operating condition and to reduce the water product cost.

Boubaker K.,ESSTT
Renewable and Sustainable Energy Reviews | Year: 2012

In this review, general features of the renewable energy sources in the North African upper zone have been studied. The primal renewable sources of energy have been identified in Algeria, Morocco and Tunisia. Taking into account concordances and divergences of the different actors in the region, a polynomial optimization scheme has been performed in order to predict future potentials and perspectives. © 2012 Elsevier Ltd. All right reserved.

Awojoyogbe O.B.,Minna Federal University Of Technology | Faromika O.P.,Federal University of Technology Akurre | Moses F.O.,P.O. Box 9352 | Dada M.,Minna Federal University Of Technology | And 2 more authors.
Current Applied Physics | Year: 2010

In this study, the Bloch NMR flow equations are modelled into diffusion equation with constant transport coefficient in terms of the NMR transverse magnetization. Mathematical conditions are established for the diffusion coefficients to be constant or spatially varied with direction. When these conditions are met, the diffusion coefficients can then be easily evaluated in terms of Boubaker polynomials for the study of flow in restricted geometries. © 2009 Elsevier B.V. All rights reserved.

Nasri W.,ESSTT
International Journal of Parallel, Emergent and Distributed Systems | Year: 2010

Today, due to many reasons, such as the inherent heterogeneity, the diversity and the continuous evolution of actual computational supports, writing efficient parallel applications on such systems represents a great challenge. To achieve good performances in these execution environments, the impact of communications on the global performances of parallel applications should not be neglected. Our objective within this work is to design an analytical model able to predict accurately the performance of communication operations on computational systems characterised by both heterogeneity and hierarchical structure. We principally aim to guarantee the accuracy of the predicted performances with a neglected additional overhead. The proposed model was applied on point-to-point and collective communication operations and showed by achieving experiments on a hierarchical cluster-based system with heterogeneous resources that the predicted performances are close to measured ones. © 2010 Taylor & Francis.

In this study, achievements, potentials and perspectives for renewable energy sources in the North African upper zone have been investigated. The renewable sources of energy, mainly solar, wind, biomass and geothermal, have been identified. Renewable energies were shown to have a promising future in the context of a connected network with the European Union, despite divergences of individual national targets and policies. Assuming a competitive, regional and stable energy framework in the region, a probabilistic optimization scheme has been proposed for a 2025 horizon within a Data Envelopment Analysis (DEA) framework. © 2011 Elsevier Ltd.

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