Boukendakdji O.,Dr. Yahia Fares University Center of Médéa |
Kadri E.-H.,Cergy-Pontoise University |
Kenai S.,Blida University
Cement and Concrete Composites | Year: 2012
This paper presents the results of an experimental investigation carried out to study the effect of granulated blast furnace slag and two types of superplasticizers on the properties of self-compacting concrete (SCC). In control SCC, cement was replaced with 10%, 15%, 20%, and 25% of blast furnace slag. Two types of superplasticizers: polycarboxylate based superplasticizer and naphthalene sulphonate based superplasticizers were used. Tests were conducted for slump flow, the modified slump test, V-Funnel, J-Ring, U-Box, and compressive strength. The results showed that polycarboxylate based superplasticizer concrete mixes give more workability and higher compressive strength, at all ages, than those with naphthalene sulphonate based superplasticizer. Inclusion of blast furnace slag by substitution to cement was found to be very beneficial to fresh self-compacting concrete. An improvement of workability was observed up to 20% of slag content with an optimum content of 15%. Workability retention of about 45 min with 15% and 20% of slag content was obtained using a polycarboxylate based superplasticizer; compressive strength decreased with the increase in slag content, as occurs for vibrated concrete, although at later ages the differences were small. © 2011 Elsevier Ltd. All rights reserved.
Agency: European Commission | Branch: FP7 | Program: CSA-SA | Phase: REGPOT-2009-2 | Award Amount: 1.12M | Year: 2009
Europe and MPC possess a good potential of well trained researchers in the field of brain function and dysfunction in disease. However, neuroscience remains poorly represented in collaborative projects amongst the Mediterranean and European countries. Yet, as the MPC access to the status of developed economies, they face severe health burden of brain dysfunction in relation with developmental issues, education, aging, neurodegenerative diseases, mental and addictive disorders. It is thus crucial for the MPC to invest in this theme of research. In this context, NUROMED aims at supporting MPC research institutions infrastructure and potential development in brain research. The project, built on existing collaborations and local networks, gathers a strong human potential from 23 Universities and research centres and complementary expertise in basic and clinical neuroscience. More precisely, the objectives are to promote and improve: (1) twinning between centres of excellence in the EU and the MPC; (2) recruitment, training and secondments in MPC centres; (3) transfer of knowledge and know-how to the MPC research centres; (4) physical research infrastructure in MPC centres. Focusing on 4 major relevant societal issues (neurodegenerative and mental diseases, neuroplasticity, adaptation to environmental stress and brain imaging), where cooperation with EU research entities can help increase the human potential and physical infrastructure in MPC, NUROMED will pave the way to the creation of solid links amongst institutions in MPC and Turkey, and to step up Euro-Mediterranean Cooperation in the field of Neurosciences. In parallel to the implementation of specific activities, NUROMED will also improve the participation of the MPC to the FP7. Finally, the project is expected to have broader impacts on other key EU policies as it contributes to the fulfilment of the neighbourhood policy, as well as the international aspect of the European R&D policy.
Djendi M.,Blida University
Computers and Electrical Engineering | Year: 2012
This paper addresses the field of stereophonic acoustic echo cancellation (SAEC) by adaptive filtering algorithms. Recently, we have proposed a new version of the fast Newton transversal FNTF algorithm for SAEC applications. In this paper, we propose an efficient modification of this algorithm for the same applications. This new algorithm uses a new proposed and simplified numerical stabilization technique and takes into account the cross-correlation between the inputs of the channels. The basic idea is to introduce a small nonlinearity into each channel that has the effect of reducing the inter-channel coherence while not being noticeable for speech due to self masking. The complexity of the proposed algorithm does not alter the complexity of the original version and is kept less than half the complexity of the fastest two-channel FTF filter version. Simulation results and comparisons with the extended two-channel normalized least mean square NLMS and FTF algorithms are presented. © 2012 Elsevier Ltd. All rights reserved.
Djendi M.,Blida University |
Bendoumia R.,Blida University
Applied Acoustics | Year: 2014
This paper addresses the problem of speech intelligibility enhancement by adaptive filtering algorithms employed with subband techniques. The two structures named the forward and backward blind source separation structures are extensively used in the speech enhancement and source separation areas, and largely studied in the literature with convolutive and non-convolutive mixtures. These two structures use two-microphones to generate the convolutive/non- convolutive mixing signal, and provide at the outputs the target and the jammer signal components. In this paper, we focus our interest on the backward structure employed to enhance the speech signal from a convolutive mixture. Furthermore, we propose a subband implementation of this structure to improve its behavior with speech signal. The new proposed subband-Backward BSS (SBBSS) structure allows a very important improvement of the convergence speed of the adaptive filtering algorithms when the subband-number is selected high. In order to improve the robustness of the proposed subband structure, we have adapted then applied a new criterion that combines the System Mismatch and the Mean-Errors criterion minimization. The proposed subband backward structure, when it is combined with this new criterion minimization, allows to enhance the output speech signal by reducing the distortion and the noise components. The performance of the proposed subband backward structure is validated through several objective criteria which are given and described in this paper. © 2013 Elsevier Ltd. All rights reserved.
Lafri M.,Blida University
Heredity | Year: 2016
Algeria represents a reservoir of genetic diversity with local sheep breeds adapted to a large range of environments and showing specific features necessary to deal with harsh conditions. This remarkable diversity results from the traditional management of dryland by pastoralists over centuries. Most of these breeds are poorly productive, and the economic pressure leads farmers to realize anarchic cross-breeding (that is, not carried out in the framework of selection plans) with the hope to increase animal’s conformation. In this study, eight of the nine local Algerian sheep breeds (D’men, Hamra, Ouled-Djellal, Rembi, Sidaoun, Tazegzawt, Berber and Barbarine) were investigated for the first time by genome-wide single-nucleotide polymorphism genotyping. At an international scale, Algerian sheep occupied an original position shaped by relations with African and European (particularly Italian) breeds. The strong genetic proximity with Caribbean and Brazilian breeds confirmed that the genetic make-up of these American breeds was largely influenced by the Atlantic slave trade. At a national scale, an alarming genetic dilution of the Berber (a primitive breed) and the Rembi was observed, as a consequence of uncontrolled mating practices with Ouled-Djellal. A similar, though less pronounced, phenomenon was also detected for the Barbarine, another ancestral breed. Genetic originality appeared to be better preserved in Tazegzawt, Hamra, D’men and Sidaoun. These breeds should be given high priority in the establishment of conservation plans to halt their progressive loss. For Berber and Barbarine that also occur in the bordering neighbor countries, urgent concerted transnational actions are needed.Heredity advance online publication, 14 September 2016; doi:10.1038/hdy.2016.86. © 2016 Macmillan Publishers Limited, part of Springer Nature.
Moulay S.,Blida University
Journal of Polymer Engineering | Year: 2013
A unique feature of molecular iodine by far, is its ability to bind to polymeric materials. A plethora of natural and synthetic polymers develop complexes when treated with molecular iodine, or with a mixture of molecular iodine and potassium iodide. Many unexpected findings have been encountered upon complexation of iodine and the polymer skeleton, including the color formation, the polymer morphology changes, the complexation sites or regions, the biological activity, and the electrical conductivity enhancement of the complexes, with polyiodides (In ̄), mainly I 3 ̄ and I5 ̄, as the actual binding species. Natural polymers that afford such complexes with iodine species are starch (amylose and amylopectin), chitosan, glycogen, silk, wool, albumin, cellulose, xylan, and natural rubber; iodine-starch being the oldest iodine-natural polymer complex. By contrast, numerous synthetic polymers are prone to make complexes, including poly(vinyl alcohol) (PVA), poly(vinyl pyrrolidone) (PVP), nylons, poly(Schiff base)s, polyaniline, unsaturated polyhydrocarbons (carbon nanotubes, fullerenes C60/C70, polyacetylene; iodine-PVA being the oldest iodine-synthetic polymer complex.
Moulay S.,Blida University
Designed Monomers and Polymers | Year: 2014
Not only does the molecular iodine play a leading role in organic synthesis but also in the polymer synthesis. Different kinds of polymerization initiated by molecular iodine are herein screened: cationic polymerization, radical polymerization, living/controlled radical polymerization (LCRP) such as reverse iodine transfer polymerization, polycondensation, and ring-opening polymerization (ROP). Also, the functionalization of polymers using molecular iodine, such as the acetylation of polysaccharides (cellulose, starch), and the use of iodine-polymer complex in organic synthesis are also discussed. Numerous natural and synthetic polymers are prone to make complexes with molecular iodine, and one feature of such complexes is their propensity as polymer-supported reagent and catalysts in many organic syntheses. © 2013 Taylor and Francis.
Moulay S.,Blida University
Polymer Reviews | Year: 2014
How does man dare to accept nature's challenges? A myriad of natural products with stunning structures and impressive properties fashion the research platforms of scientists, particularly the chemists and biologists. Indeed, research work undertaken by the latter scientists has unveiled concealed nature's mysteries. Of these mysteries, nature provides us with unusual adhesives in the form of L-DOPA-containing proteins, existing within the mussel feet and commonly called mussel foot proteins (fps). The uniqueness of these bioadhesives resides in their adhering performance to all kinds of surfaces and, more astonishing, under a wet environment. Up to six fps for Mytilus species (Mfps) were identified with varying extents of DOPA content. Improved adhesion performance was even observed for the recombinant Mfps expressed in Escherichia coli. Amine and catechol functionalities are crucial moieties and do play a synergetic effect for such adhesion. In addition, the in vivo crosslinking generated via an oxidative process of catechol units of DOPA to o-quinone groups at marine pH (8.5), takes part into this adhesion occurrence. In vitro crosslinking was achieved with oxidizing agents such as periodate ion and Fe(III), resulting in oxidative crosslinking (covalent crosslinking) and coordinative one (non-covalent crosslinking), respectively. To delve into the enigmatic phenomenon and unravel the chemistry behind, scientists strive to experiment their adhesive ability to substrata of different chemical natures, to make synthetic analogues, that is, bioinspired mussel adhesives, and apply the same work-up. Catechol and its derivatives such as DOPA and dopamine were either polymerized under simulated natural conditions or attached to skeletons of several synthetic polymers and biopolymers. The ongoing thus-biased research has now opened new avenues in biomedicals, hydrogels applications, antifouling processes, and nanotechnology. As friendly operation is greatly coveted, one promising fact is the surgical suture with such bioadhesive and the making of self-healing related materials. © 2014 Copyright Taylor & Francis Group, LLC.
Amrouche B.,Center for Development of Renewable Energies (CDER) |
Guessoum A.,Blida University |
Belhamel M.,Center for Development of Renewable Energies (CDER)
Applied Energy | Year: 2012
This paper proposes a simple behavioural model for photovoltaic modules. This model can be used to characterise current-voltage and power-voltage outputs of photovoltaic modules as a function of solar module temperature and solar radiation intensity. Such a model cannot only serve as a tool to study the I-V curve and its maximum power point characteristics but also to design photovoltaic power systems and power converters used for PV applications. It can also be used for performance rating. This model has first been developed to study the maximum power point characteristics by exploring the existing similarity between the photovoltaic module I-V characteristic and the step response of a first-order system. It has the advantage to use only parameters that are available on the data sheet. To construct the proposed model, measured I-V curves at different working conditions (solar radiation intensity and ambient temperature) were used, then other I-V characteristics corresponding to different working conditions have been used to validate it. The obtained results show a high degree of correspondence between the real outdoor measured I-V characteristics and those given by the developed model. © 2011 Elsevier Ltd.
Ghernaout D.,Blida University
Desalination and Water Treatment | Year: 2013
This review discusses the advanced oxidation process (AOP) phenomena in electrocoagulation (EC) process. AOPs have been broadly defined as near ambient temperature treatment processes based on highly reactive radicals, especially the hydroxyl radical as the primary oxidant. In principle, as water-containing colloidal particulates, oils, or other contaminants move through the applied electric field, there may be ionisation, electrolysis, hydrolysis, and free-radical formation which may alter the physical and chemical properties of water and contaminants. Further, when the electrochemical reactors operate at a high cell potential and an anodic process occurs in the potential region of water discharge, hydroxyl radicals are generated. In order to get more probabilities to have free radicals formation in EC, ultrasound during EC may be very useful as discussed by some authors. Further, EC process at pH less than 3 has more chance to produce hydroxyl radicals formation. Finally, this review concludes that there is no proof of the presence of AOP phenomena in EC process and more research is needed here focusing on free radicals formation. © 2013 © 2013 Balaban Desalination Publications.