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Laghouat, Algeria

The University of Laghouat is a university in the city of Laghouat, the capital city of Laghouat Province in Algeria, North Africa. It was established in 1986 and given full university status in 2001. Wikipedia.

Ghernaout D.,Blida University | Ghernaout B.,University of Laghouat
Desalination and Water Treatment | Year: 2012

The coagulation/flocculation (C/F) processes are mainly due to charge neutralisation (CN) and sweep flocculation (SF) mechanisms. However, the SF mechanism has also its CN property moreover than its well-known weighting characteristic. On this weighting characteristic, the literature has usually focused without taking in consideration the SF's CN property. This review discusses the implicated mechanisms in destabilisation of colloids and aggregation of flocs. Colloids are very small particles that have extremely large surface area. The consequence of this smallness in size and mass and largeness in surface area is that in colloidal suspensions: gravitational effects are negligible and surface phenomena predominate. Hence, during C/F process, colloids are removed by CN and SF mechanisms which act on the anionic charge of the colloid by its neutralisation prior to its removal by sedimentation/filtration. The sweep flocs can be described as large aggregates of Al(OH)3/Fe(OH)3 that are formed when Al/Fe salt is added to water. Further, sweep flocs are positively charged and the colloids of clay minerals abundantly found in the water are negatively charged. As a result, the colloidal particles are electrostatically attached to the sweep flocs in the neutral pH water as to the hydrolysed metallic cations. Even if researches have greatly elucidated the growth, breaking and the re-growth of flocs, further research is required to understand CN and SF mechanisms and optimise the C/F process at the nano level. © 2012 Desalination Publications. All rights reserved.

Cheknane A.,University of Laghouat
Progress in Photovoltaics: Research and Applications | Year: 2011

The aim of this work is to present an optimized model of metallic micro-grid used as anode electrode in organic photovoltaic devices excluding the use of expensive ITO (Indium Tin Oxide). A design of circular grid, adapted for silcon-based solar cells, is proposed here. A clear advantage of using the grid as opposed to ITO is the elimination of the absorptive losses the ITO adds to the structure. In order to optimize the collecting grid dimensions one must choose a compromise between the resistive losses, represented by the series resistance Rs, and the shadowing loss. Therefore, in order to find the best geometry of the grid, a comparative study has been done between the linear geometry and the circular one. Our results show clearly that the efficiency is enhanced when using the circular geometry. © 2010 John Wiley & Sons, Ltd.

Benmouiza K.,Abou Bekr Belkaid University Tlemcen | Cheknane A.,University of Laghouat
Energy Conversion and Management | Year: 2013

In this paper, we review our work for forecasting hourly global horizontal solar radiation based on the combination of unsupervised k-means clustering algorithm and artificial neural networks (ANN). k-Means algorithm focused on extracting useful information from the data with the aim of modeling the time series behavior and find patterns of the input space by clustering the data. On the other hand, nonlinear autoregressive (NAR) neural networks are powerful computational models for modeling and forecasting nonlinear time series. Taking the advantage of both methods, a new method was proposed combining k-means algorithm and NAR network to provide better forecasting results. © 2013 Elsevier Ltd. All rights reserved.

The present paper provides a statistical approach to evaluate the effect of different sand types on the properties of self-compacting concrete (SCC). A mixture design modelling approach was used to highlight the effects of river sand (RS), crushed sand (CS) and dune sand (DS) as proportions in binary and ternary systems, on flowability, passing ability, segregation and mechanical strength of SCC. The responses of the derived statistical models are slump flow, v-funnel time, L-box, stability and compressive strength at 2, 7 and 28 days. The derived mathematical models make it possible to illustrate the variation of different responses in ternary contour plots with respect to the proportions of RS, CS and DS. This provides flexibility to optimize RS, CS and DS blends with tailor-made of a given property that suit particular recommendations. Results indicate that when flowability requirements are combined, proportions of DS and CS in binary or ternary systems with RS must be below 0.24 and 0.6 respectively. Moreover, it is shown that passing ability can be satisfied by using a CS proportion above 0.3 in RS-CS binary system and above 0.65 in CS-DS binary system. On other hand, proportions above 0.5 of CS in RS-CS binary system and above 0.2 of DS in RS-DS binary system are recommended to meet stability limits. Results also indicate that compressive strength at 2, 7 and 28 days increased with the increase of CS proportion and decreased with the increase of DS proportion in binary and ternary systems. © 2013 Elsevier Ltd. All rights reserved.

Ghernaout D.,Blida University | Ghernaout B.,University of Laghouat | Naceur M.W.,Blida University
Desalination | Year: 2011

Green chemistry (GC) is the key to sustainable development as it will lead to new solutions to existing problems. Moreover, it will present opportunities for new processes and products and at its heart is scientific and technological innovation. This paper aims to contribute to a better understanding of the new challenges that chemistry is facing. A particular emphasis is accorded to the need for the development of environmentally friendly technologies for water treatment where GC can be satisfied. Indeed, following the establishment of the 12 Principles of GC, there has been a steady growth in our understanding of what GC means. Furthermore, there are great perspectives relating to the greening of chemical water treatment, especially in terms of ferrate(VI) adding, as oxidant/disinfectant/coagulant in the same time, and microchannel reactors which would be considered as promising devices for water treatment due to their proved advantages. © 2011 Elsevier B.V.

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