Toward hydrogen enriched natural gas “HCNG” fuel on the algerian road

The Algerian transport sector is still largely dependent on petroleum. Pollution emitted by this sector is constantly increasing with the expansion of the automobile fleet. Thus, there is a pressing need for use of cleaner and economically viable alternative fuels. Therefore, the use of Hydrogen enriched Compressed Natural Gas (HCNG) is expected to play a significant role to reach this target. When hydrogen and natural gas are used together in an internal combustion engine, large benefits are possible. Algeria has significant resources and potential to introduce this new fuel. The development of HCNG as a transportation fuel allows an entry point for hydrogen in the transportation sector. The aim of this paper is to discuss strategic ways to introduce HCNG as road fuel, in Algeria. Two fundamental strategic elements were designed to introduce the Hydrogen Enriched Natural Gas as a transportation fuel. These are, the development of compressed natural gas as a road fuel, and the completion of the MedHySol project. The MedHySol project includes the production and the distribution of solar produced hydrogen, and involves the project HySolThane intended for the development of HCNG fuel road with 8% vol of Hydrogen in Natural Gas.     

Low-Temperature Preparation and Magnetic Properties of V-Doped SnO2 Nanoparticles

A solid solution of vanadium (V)-doped tin oxide (SnO₂) particles of average diameter 2 nm and V content of 19 at.% was prepared at normal pressure and low temperature (100°C) by mixing wet SnO₂ gel SnO₂· x H₂O with a boiling solution of vanadium oxide (V₂O₅). Experimental characterizations using X-ray, electron diffraction, and transmission electron microscope show evidence of a pure single phase. The nanoparticles exhibit a mixed magnetic behavior, namely paramagnetic and ferromagnetic. Their thermal stability is also investigated. At higher temperature, 850°C, some amount of Fe precipitates from the solid solution.     

Alternate strand DNA triple helix-mediated inhibition of HIV-1 U5 long terminal repeat integration in vitro

Integration of the human immunodeficiency virus (HIV) DNA into the host genome is an obligatory process in the replicative life cycle of the virus. This event is mediated in vitro by integrase, a viral protein which binds to specific sequences located on both extremities of the DNA long terminal repeats (LTRs). These sites are highly conserved in all HIV genomes and thus provide potential targets for the selective inhibition of integration. The integrase-binding site located on the HIV-1 U5 LTR end contains two adjacent purine tracts on opposite strands, 5' . . . GGAAAATCTCT-3'/3'-CCTTTTAGAGA . . . 5', in parallel orientations. A single strand oligonucleotide 5'-GGTTTTTGTGT-3' was designed to associate with these tracts via its ability to form a continuous alternate strand DNA triplex. Under neutral pH and physiological temperature, the oligonucleotide, tagged with an intercalator chromophore oxazolopyridocarbazole, formed a stable triplex with the target DNA. The occurrence of this unusual triplex was demonstrated by both DNase I footprinting and electron microscopy. The triplex inhibits the two steps of the integrase-mediated reactions, namely, the endonucleolytic cleavage of the dinucleotide 5'-GT-3' from the 3' end of the integration substrate and the integration of the substrate into the heterologous target DNA. The midpoints for both inhibition reactions were observed at oligonucleotide concentrations of 50-100 nM. We believe that these results open new possibilities for the specific targeting of viral DNA LTR ends with the view of inhibiting integration under physiological conditions.     

Binding of Net-Fla, a netropsin-flavin hybrid molecule, to DNA: molecular mechanics and dynamics studies in vacuo and in water solution

We have studied the binding of the hybrid netropsin-flavin (Net-Fla) molecule onto four sequences containing four A. T base pairs. Molecular mechanics minimizations in vacuo show numerous minimal conformations separated by one base pair. 400 ps molecular dynamics simulations in vacuo have been performed using the lowest minima as the starting conformations. During these simulations, the flavin moiety of the drug makes two hydrogen bonds with an amino group of a neighboring guanine. A 200 ps molecular dynamics simulation in explicit water solution suggests that the binding of Net-Fla upon the DNA substrate is enhanced by water bridges. A water molecule bridging the amidinium of Net-Fla to the N3 atom of an adenine seems to be stuck in the drug-DNA complex during the whole simulation. The fluctuations of the DNA helical parameters and of the torsion angles of the sugar-phosphate backbone are very similar in the simulations in vacuo and in water. The time auto-correlation functions for the DNA helical parameters decrease rapidly in the picosecond range in vacuo. The same functions computed from the water solution molecular dynamics simulations seem to have two modes: the rapid mode is similar to the behavior in vacuo, and is followed by a slower mode in the 10 ps range.     

Numerical analysis of the crack growth path in the cement mantle of the reconstructed acetabulum

In this study, we use the finite element method to analyze the propagation's path of the crack in the orthopedic cement of the total hip replacement. In fact, a small python statement was incorporated with the Abaqus software to do in loop the following operations: extracting the crack propagation direction from the previous study using the maximal circumferential stresses criterion, drawing the new path, meshing and calculating again (stresses and fracture parameters). The loop is broken when the user's desired crack length is reached (number of propagations) or the value of the mode I stress intensity factor is negative. Results show that the crack propagation's path can be influenced by human body posture. The existing of a cavity in the vicinity of the crack can change its propagation path or can absolutely attract it enough to meet it. Crack can propagate in the outward direction (toward the acetabulum bone) and cannot propagate in the opposite direction, the mode I stress intensity factor increases with the crack length and that of mode II vanishes.     

MedHySol: Future federator project of massive production of solar hydrogen

Mediterranean Hydrogen Solar (MedHySol) is a federator project for development of a massive hydrogen production starting from solar energy and its exportation within a framework of a Euro–Maghrebian Cooperation project for industrial and energetic needs in the Mediterranean basin. The proposal of this project is included in the Algiers Declaration's on Hydrogen from Renewable Origin following the organization of the first international workshop on hydrogen which was held in 2005. Algeria is the privileged site to receive the MedHySol platform. The objective of the first step of the project is to realize a technological platform allowing the evaluation of emergent technologies of hydrogen production from solar energy with a significant size (10–100 kW) and to maintain the development of energetic rupture technologies. The second step of the project is to implement the most effective and less expensive technologies to pilot great projects (1–1000 MW). In this article we present the potentialities and the feasibility of MedHySol, as well as the fundamental elements for a scientific and technical supervision of this great project.     

Extraction of naphthalene. Optimization and application to an industrial rejected fuel oil

The extraction efficiency of naphthalene from an organic phase depends essentially on the choice of extractant. It can be enhanced through the optimization of operating parameters. The organic phase studied was a fuel oil rejected at the process end of the coke gas treatment in an industrial plant of Annaba (Algeria). The mixture of methanol–phenol has been selected as extractant for its best efficiency. The amount of naphthalene in the oil phase was analyzed by refractometry and verified by infrared spectroscopy. The temperature, the density of methanol–phenol mixture and the quantity of extractant, were considered as the main parameters which affect the performance of extraction. Response surface methodology was applied to investigate the yield of extraction. A Box-Behnken design was used to produce models for objective responses based on parameters that have significant probabilities. It was developed by using these three main parameters at three levels. Analysis of variance showed that temperature and the volume ratio are the most affecting parameters on extraction yield. The developed regression equations described interdependencies between the input parameters and yield of extraction as responses. The results that were treated statistically were very interesting and allowed to deduce the optimum conditions for the best extraction efficiency which was in order to 80.38%. The application of extraction in these conditions has permitted to regenerate the fuel oil rejected by the industrial unit for other uses. The phenol–methanol mixture containing naphthalene can also be regenerated (91.8% of methanol and 94.2% of phenol) and more than 1 ton of pure naphthalene per day can be recovered. This could be very important for the industrial unit on decreasing the cost of the fuel consumption and more profits by producing pure naphthalene.     

Extending software component models with the master–worker paradigm

Recent advances in computing and networking technologies—such as multi-core processors and high bandwidth wide area networks—lead parallel infrastructures to reach a higher degree of complexity. Programmers have to face with both parallel and distributed programming paradigms when designing an application. This is especially true when dealing with e-Science applications. Moreover, as parallel processing is moving to the mainstream, it does not seem appropriate to rely on low-level solutions requiring expert knowledge. This paper studies how to combine modern programming practices such as those based on software components and one of the most important parallel programming paradigms which is the well-known master–worker paradigm. The goal is to provide a simple and resource transparent model while enabling an efficient utilization of resources. The paper proposes a generic approach to embed the master–worker paradigm into software component models and describes how this generic approach can be implemented within an existing software component model. The overall approach is validated with synthetic experiments on clusters and the Grid’5000 testbed.