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Search Results: 1 - 10 of 162 matches for " Djamel Boubetra "
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Surfaces Characterization by Ionic Bombardment
Djamel Boubetra
Journal of Engineering and Applied Sciences , 2012,
Abstract: The causes for the Anisotropy in the angle distribution of sprayed atoms is yet extensively unexplained. Therefore experimental investigations should be carried out to this question. The ions beam was used for comparing investigation between the distributions of back steered ions and sprayed atoms. We know that the pulverization of crystals shows an anisotropic angular distribution of pulverized atoms. The appearance of this phenomenon is initiated once Wehner spots are obtained by putting a receptor in front of the sample, which shows a correlation with the principal crystallographic axes. Another study shows, that till now the studies and works already done are not strongly founded in the sense of the correspondence of the Wehner spots and the principal axes of the crystals. Measurements are represented in many works and during the last years detailed studies on gold crystals (111). Principally the gold atoms emissions have appeared in the directions (110) and (111) for which the intensity to energy ratio of projectile ions is modified. Emissions directions are to be maintained in addition to representations and for omitted raisons directions changes have to be taken into account. After the studies of deviations in the emission directions appear during the copper crystals pulverization. The authors allocate this fact to the influence of the forces of superficial links which should generally lead to a preference of the particles emission in the normal direction to the surface. The question is who it makes that the link ratio for different crystals directions have a different response; however, it is shown that the application of an ionic beam emitter, to examine the interference of the direction emissions of the pulverized atoms with principal crystallographic axes, is necessary.
Development of Ion Source with Cold Cathode for Sputtering
Djamel Boubetra
Journal of Engineering and Applied Sciences , 2012,
Abstract: Ion sources are of practical importance for scientific research and industrial applications. The developed ion sources are used for evaporation on single crystals. We present in this research the construction and the optimisation of a low-energy ion radiation source. Which supplies a high ion current density using a cold cathode with low power. The physical aspects and the different possibilities for resolution of the problem are discussed with investigations on the parameters of the developed Duoplasmatron source. The conception is achieved by experimental investigations on selected construction versions. We show an interesting experimental results concerning the relation between the pressure and volume of the hollow cathode. The results are compared to those obtained by mass spectrometry at Penning and glow cathode ion source.
Development of Magnetic Hollow Cold Cathode for Ion Source
Djamel Boubetra,M. Bouafia
Journal of Applied Sciences , 2008,
Abstract: The research presented in this study focuses on the development of ion source with hollow cold cathodes which supplies low-power and high ion-current density applications. The theoretical and experimental results were used to design a second-generation laboratory model, low-current hollow cathode. Present experiment is to design a hollow cold cathode with two application possibilities.
Mathematical Modeling of Amorphous Layers Growth by Low Energy Ion Implantation
Djamel Boubetra,M. Bouafia
Journal of Applied Sciences , 2008,
Abstract: In this study, a simple mathematical model has been developed for the description of amorphous layer growth by low ion energy implantation. The model concerns the lower and higher dose range. It has been assumed that the damage depth distribution can be approximated by a Gaussian. The thicknesses of the amorphous layer and voids film, obtained assuming multi-layer model, have been found in relation to the ion damage straggling and amorphization threshold. The model concept and the corresponding calculations are discussed in details.
Relationship between cation exchange capacity and the saline phase of Cheliff sol  [PDF]
Djamel Saidi
Agricultural Sciences (AS) , 2012, DOI: 10.4236/as.2012.33051
Abstract: T Measurements of the cation exchange capacity (CEC) show significant soil properties, in particular its ability to retain the cations because of their mobility in the soil. Thirteen soil samples rich in electrolytes of the Cheliff plain (Algeria) were analyzed in order to measure their CEC and to draw up the existing relationship between texture, organic matter content and pH. In calcareous soils, the CECe values are always higher than those measured at pH 7. Regression equations using the percentages of organic carbon and clay as independent variables would make it possible to estimate 90% of the variability of the CEC measured in the ammonium acetate buffered at pH 7 and 89% of the variability for that measured at the pH of the soil. These percentages are particularly useful due to the fact that they make it possible to estimate the CEC of the soil according to the pH only starting from the organic matter and texture. The correlations between the salinity indices, the parameters of the saline phase and the physical properties, show that the cobalt-hexamine method makes it possible to characterize the soil of this plain with more precision than the Metson method. It constitutes a means for following-up the chemical quality of the soil. The Metson method makes it possible to approach the reactivity of the soil in relation with the geometry of the components. The measurement of the CEC at pH 7 makes it possible to envisage the water content at the permanent wilting point of the plants. Finally, it is noticed that a sodisation of the adsorbing compound, which consequently generates a reduction in the structural stability and a reduction in the infiltration always leads to the salinity in these soil types.
The Best Available Technology of Water/Wastewater Treatment and Seawater Desalination: Simulation of the Open Sky Seawater Distillation  [PDF]
Djamel Ghernaout
Green and Sustainable Chemistry (GSC) , 2013, DOI: 10.4236/gsc.2013.32012
Abstract: This review suggests the concept of the best available technology of water/wastewater treatment and seawater desalination which is in fact a simulation of the seawater distillation at the open sky: coagulation in salty water aerated basin/ coagulation using seawater as coagulant solution with distillation using stored solar energy followed by waterfall on a natural mountain. This natural, green, and technico-economical technology is composed of three steps: the first one is coagulation which may be achieved: 1) in salty water aerated basin (air stripping, AS; dissolved air flotation, DAF) where the raw water is diluted in seawater; or 2) in conventional coagulation using seawater as coagulant solution instead of alum/ferric salts. The first option seems to be more natural as it simulates river water dilution in seawater and the second one is more practical for rapid water consummation. For colloids and microorganisms’ removal, double-layer compression and charge neutralisation, as main coagulation and disinfection mechanisms, would be involved in the first and second options, respectively. Aerated basin (AS/DAF) reproduces the natural aeration to simulate healthy natural water basin. Using stored solar energy, distillation as the best liquid-solid/liquid-liquid separation process provides the removal of dissolved pollutants. For well balanced calco-carbonic equilibrium, the last step of this green treatment is the waterfall on a natural mountain providing useful gases, dissolved oxygen and carbon dioxide, and mineral salts to the water.
Rehabilitation as a Catalyst of Sustaining a Living Heritage: The Case of Souk Waqif in Doha, Qatar  [PDF]
Djamel Boussaa
Art and Design Review (ADR) , 2014, DOI: 10.4236/adr.2014.23008
Abstract: In recent years, mixed use urban fabric has become one of the new concerns of urban planners, urban designers, and architects. In many historic centers, urban diversity has been achieved spontaneously and it responded to the local needs of people at that time. However, today this urban space diversity is being seriously threatened. Souk Waqif, is one of the last surviving historic urban spaces in Doha. Due to the rapid urbanisation following the discovery of oil in 1939 and the beginning of its exportation in 1949, many houses in the Souk have been abandoned to become shelters for low income workers. Overcrowding, neglect, and lack of maintenance have resulted in more dilapidation of the souk and make it look like an urban slum in the heart of Doha. This paper attempts to assess the level of diversity of urban spaces existing in the souk and tries to identify if they form threats to its authenticity. This research is based on empirical research, onsite observations and interviews with the users. The outcomes of the survey and of site visits can inform us about the quality of the area and how it can be enhanced in the future.
Survey of Clustering Schemes in Mobile Ad hoc Networks  [PDF]
Abdelhak Bentaleb, Abdelhak Boubetra, Saad Harous
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.52B002
Abstract: Mobile ad-hoc networks (MANETs) are a specific kind of wireless networks that can be quickly deployed without pre- existing infrastructures. They are used in different contexts such as collaborative, medical, military or embedded applications. However, MANETs raise new challenges when they are used in large scale network that contain a large number of nodes. Subsequently, many clustering algorithms have emerged. In fact, these clustering algorithms allow the structuring of the network into groups of entities called clusters creating a hierarchical structure. Each cluster contains a particular node called cluster head elected as cluster head according to a specific metric or a combination of metrics such as identity, degree, mobility, weight, density, etc. MANETs has drawbacks due to both the characteristics of the transmission medium (transmission medium sharing, low bandwidth, etc.) and the routing protocols (information diffusion, path finding, etc.). Clustering in mobile ad hoc networks plays a vital role in improving resource management and network performance (routing delay, bandwidth consumption and throughput). In this paper, we present a study and analyze of some existing clustering approaches for MANETs that recently appeared in literature, which we classify as: Identifier Neighbor based clustering, Topology based clustering, Mobility based clustering, Energy based clustering, and Weight based clustering. We also include clustering definition, review existing clustering approaches, evaluate their performance and cost, discuss their advantages, disadvantages, features and suggest a best clustering approach.
Hydrological Study of Watersheds Arid and Semi-Arid South-Eastern Algeria (Chott Melghir, Chott El Hodna and Highlands Constantine)  [PDF]
Fares Belagoune, Djamel Boutoutaou
International Journal of Geosciences (IJG) , 2013, DOI: 10.4236/ijg.2013.410145
Abstract:

The objective of the study is to establish the hydrological characteristics, the hydrological behavior of river basins in arid and semi-arid south-eastern Algeria (establish of methodologies and necessary working tools for planning the development and management of water resources). The study on floods in Algeria is established by the National Agency of Water Resources (ANRH shows that the country is confronted with the phenomenon of very destructive floods and floods especially in arid and semi-arid regions). Flooding of rivers in these areas is less known. They are characterized by their sudden duration (rain showers, thunderstorm). The duration of the flood is in the order of minutes to hours. The human and material damages caused by these floods are still high. The study area encompasses three watersheds in semi-arid, arid south and Algeria. There are pools of Chott-Melghir (68,751 km2), highland Constantine-07 (9578 km2) and El Hodna-05 basin (25,843 km2). The total area of this zone is about 104,500km2.

Recovery of Heavy Metal Using Solvent Impregnated Resin (SIR) Coupled with Donnan Dialysis  [PDF]
Dalila Berdous, Djamel Eddine Akretche
Materials Sciences and Applications (MSA) , 2012, DOI: 10.4236/msa.2012.310103
Abstract: A membrane process for metal recovery from aqueous solutions was studied. Metal ions diffused from the feed compartment to the stripping compartment through an hybrid Donnan dialysis which consists to combine two ion exchange membranes with solvent impregnated resin (SIR). The aim of this work is to study the recovery of Pb(II), Ag(I) and Cu(II) from nitrate solutions by using SIR combined with classical Donnan dialysis. The resin has been prepared by impregnating the Amberlite XAD-4 using three different extractants namely: di-2-ethyl hexyl phosphine acide (D2EHPA), tris-octyl phosphine oxide (TOPO) and Diphenylthiourea (DPT). Experiments were performed as a function of nature of the extractant impregnated on the XAD-4 resin as well as the concentration in the resin phase, the stripping pH, the concentration ratio of metal ions in the feed compartment and the nature of the counter ions in strip compartment. The results show that the D2EHPA is the better extractant for the metal ions used in this work, and it’s shown a good selectivity for the separation between ions.
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