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Search Results: 1 - 10 of 461880 matches for " A. Bellaouchou "
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Phosphate of Aluminum as Corrosion Inhibitor for Steel in H3PO4
L. Malki Alaoui,S. Kertit,A. Bellaouchou,A. Guenbour
Portugaliae Electrochimica Acta , 2008,
Abstract: The influence of phosphate of aluminum (PA) on the corrosion inhibition of mild steel in phosphoric acid solution was studied using the weight-loss method. The electrochemical performance of the inhibitors was also investigated through potentiodynamic polarisation and EIS measurements. The inhibition efficiency of inhibitor increases with concentration to attain 84 % at 10-2M of PA in 0.33 M H3PO4. Polarization studies show that PA is a mixed-type inhibitor and acts both on the cathodic and anodic reactions without changing the mechanism of the hydrogen evolution reaction. The inhibition efficiency of PA is temperature-dependent in the range 298 - 363 K, the associated activation energy has been determined. PA adsorbs on the steel surface according to a Langmuir isotherm adsorption model.
Phosphate of Aluminum as Corrosion Inhibitor for Steel in H3PO4
Alaoui,L. Malki; Kertit,S.; Bellaouchou,A.; Guenbour,A.; Benbachir,A.; Hammouti,B.;
Portugaliae Electrochimica Acta , 2008,
Abstract: the influence of phosphate of aluminum (pa) on the corrosion inhibition of mild steel in phosphoric acid solution was studied using the weight-loss method. the electrochemical performance of the inhibitors was also investigated through potentiodynamic polarisation and eis measurements. the inhibition efficiency of inhibitor increases with concentration to attain 84 % at 10-2m of pa in 0.33 m h3po4. polarization studies show that pa is a mixed-type inhibitor and acts both on the cathodic and anodic reactions without changing the mechanism of the hydrogen evolution reaction. the inhibition efficiency of pa is temperature-dependent in the range 298 - 363 k, the associated activation energy has been determined. pa adsorbs on the steel surface according to a langmuir isotherm adsorption model.
Corrosion Behaviour of a Highly Alloyed Austenitic Alloy UB6 in Contaminated Phosphoric Acid
M. Boudalia,A. Guenbour,A. Bellaouchou,R. M. Fernandez-Domene,J. Garcia-Anton
International Journal of Corrosion , 2013, DOI: 10.1155/2013/363826
Abstract: The influence of temperature (20–80°C) on the electrochemical behaviour of passive films anodically formed on UB6 stainless steel in phosphoric acid solution (5.5?M H3PO4) has been examined by using potentiodynamic curves, electrochemical impedance spectroscopy, and Mott-Schottky analysis. UB6 stainless steel in contaminated phosphoric acid is characterised by high interfacial impedance, thereby, illustrating its high corrosion resistance. The obtained results show that the films behave as n-type and p-type semiconductors in the potential range above and below the flat band potential, respectively. This behaviour is assumed to be the consequence of the semiconducting properties of the iron oxide and chromium oxide regions which compose the passive film. 1. Introduction In the phosphoric acid industry, the main stages of the wet process phosphoric acid (WPA) manufacture involve the attack of phosphate ore by concentrated sulphuric acid (98%), filtration of the pulp, and concentration of acid [1]. Phosphoric acid in pure state is not very corrosive compared to nitric or sulphuric acids, but this process generates severe corrosion problems of the equipments made of stainless steels due to the presence of impurities such as chlorides, fluorides, and sulphides [1–4]. Depending on the nature of phosphates and the type of phosphoric acid manufacturing process used, the equipments (reactors, agitators, pumps, drain, etc.) are subjected to slower or faster deterioration [1]. The choice of materials used in this industrial process plays an important role since they must have both good chemical and mechanical resistance. These two characteristics are not always easy to obtain and a tradeoff between these properties must be reached [5]. In this sense, austenitic stainless steels are a good choice for phosphoric media. In this study, a highly alloyed austenitic stainless steel (UB6) has been used. Stainless steels proved their good corrosion resistance in acid solutions. It was shown in the literature that chloride and fluorides ions accelerated the anodic process by altering passivity and activating the material dissolution rate [6–14]. UB6 stainless steel is used extensively in phosphoric acid industry, because of its good corrosion resistance; passive films formed on its surface have been the subject of some investigations [15]. The major disadvantage of these new alloys is their high cost compared with conventional stainless steels, due to the higher percentage of the alloying elements such as Cr, Ni, and Mo, as well as the complexity of the fabrication process
Accumulation of Copper, Lead, Chrome, Cadmium in Some Tissues of Procambarus clarkii in Rharb Region in Morocco  [PDF]
Ikram El Qoraychy, Mohamed Fekhaoui, Abdellah El Abidi, Rachid Benakame, Abdelkbir Bellaouchou, Ahmed Yahyaoui
Journal of Geoscience and Environment Protection (GEP) , 2015, DOI: 10.4236/gep.2015.38008
Abstract: Different concentrations of four metals namely copper, lead, chrome and cadmium were evaluated in crayfish Procambarus clarkii tissues (carapace, flesh) for a six-month period, from March to August 2013 in the Rharb of Morocco (Lagoon Merja Zerga and Nador canal). The determination of heavy metals was carried using atomic absorption spectroscopy Varian VV20. The results obtained revealed a metal’s contamination of Procambarus clarkii in both sites. Concentrations of heavy metals examined Procambarus clarkii carapace ranged as follows: Merja Zerga (Pb 2.07 - 6.7 μg/g; Cu 2.9 - 9.97 μg/g; Cr 0.89 - 14.22 μg/g dry weight) and Nador canal: (Pb 0.08 - 7.8 μg/g; Cu 3.40 - 9.3 μg/g ; Cr 0.87 - 3.5 μg/g dry weight). Concentrations of heavy metals found in flesh were as follows: Merja Zerga (Pb 0.02 - 5.25 μg/g; Cu 9.58 - 23.59 μg/g; Cr 0 - 2.71 μg/g dry weight) and Nador canal (Pb 0.06 - 6.81 μg/g; Cu 9.5 - 37.20 μg/g; Cr 0 - 3.23 μg/g dry weight). The distribution of those metals in Procambarus clarkii shows high levels of contamination for lead, copper and chrome with an absence of cadmium in both sites (Merja Zerga and Nador canal). The concentrations differed in carapace and flesh.
The Spread of Infectious Disease on Network Using Neutrosophic Algebraic Structure  [PDF]
A. Zubairu, A. A. Ibrahim
Open Journal of Discrete Mathematics (OJDM) , 2017, DOI: 10.4236/ojdm.2017.72009
Abstract: Network theory and its associated techniques has tremendous impact in various discipline and research, from computer, engineering, architecture, humanities, social science to system biology. However in recent years epidemiology can be said to utilizes these potentials of network theory more than any other discipline. Graph which has been considered as the processor in network theory has a close relationship with epidemiology that dated as far back as early 1900 [1]. This is because the earliest models of infectious disease transfer were in a form of compartment which defines a graph even though adequate knowledge of mathematical computation and mechanistic behavior is scarce. This paper introduces a new type of disease propagation on network utilizing the potentials of neutrosophic algebraic group structures and graph theory.
A Comparative Investigation of Lead Sulfate and Lead Oxide Sulfate Study of Morphology and Thermal Decomposition  [PDF]
S. A. A. Sajadi
American Journal of Analytical Chemistry (AJAC) , 2011, DOI: 10.4236/ajac.2011.22024
Abstract: The compound lead oxide sulfate PbSO4.PbO was prepared in our laboratory. The Thermal behavior of PbSO4 was studied using techniques of Thermogravimetry under air atmosphere from 25 to 1200°C. The identity of both compounds was confirmed by XRD technique. Results obtained using both techniques support same decomposition stages for this compound. The electron microscopic investigations are made by SEM and TEM. The compound is characterized by XRD and the purity was determined by analytical Methods. Also a series of thermogravimetric analysis is made and the ideal condition is determined to convert this compound to pure lead oxide.
Metal ion-binding properties of L-glutamic acid and L-aspartic acid, a comparative investigation  [PDF]
S. A. A. Sajadi
Natural Science (NS) , 2010, DOI: 10.4236/ns.2010.22013
Abstract: A comparative research has been developed for acidity and stability constants of M(Glu)1, M(Asp)2 and M(Ttr)3 complexes, which have been determined by potentiometric pH titration. Depending on metal ion-binding properties, vital differences in building complex were observed. The present study indicates that in M(Ttr) com-plexes, metal ions are arranged to the carboxyl groups, but in M(Glu) and M(Asp), some metal ions are able to build chelate over amine groups. The results mentioned-above demonstrate that for some M(Glu) and M(Asp) complexes, the stability constants are also largely determined by the affinity of metal ions for amine group. This leads to a kind of selectivity of metal ions, and transfers them through building complexes accompanied with glutamate and aspartate. For heavy metal ions, this building complex helps the absorption and filtration of the blood plasma, and consequently, the excursion of heavy metal ions takes place. This is an important method in micro-dialysis. In this study the different as-pects of stabilization of metal ion complexes regarding to Irving-Williams sequence have been investigated.
Determining the Basaltic Sequence Using Seismic Reflection and Resistivity Methods  [PDF]
A. Alanezi, A. Qadrouh
Open Journal of Geology (OJG) , 2013, DOI: 10.4236/ojg.2013.32B004

This study was carried out in Harat Rahat (south of Almadinah Almonwarah) using seismic reflection and resistivity methods. The main objectives of this study are to determine the extent of the basaltic layer and to define the subsurface faults and fractures that could affect and control the groundwater movement in the study area. A 2D seismic profile was acquired and the result shows that the subsurface in the study area has a major fault. We obtained a well match when the seismic result was compared with drilled wells. As a complementary tool, the resistivity method was applied in order to detect the groundwater level. The results of the resistivity method showed that six distinct layers have been identified. The interpretation of these six layers show that the first three layers, the fourth layer, the fifth layer and the bottom of the section indicated various subsurface structures and lithologies; various basaltic layers, fractured basalt, weathered basement and fresh basaltic layers, respectively. It is obvious that the eventual success of geophysical surveys depend on the combination with other subsurface data sources in order to produce accurate maps.

Equilibria and Stability in Glycine, Tartrate and Tryptophan Complexes, Investigation on Interactions in Cu(II) Binary and Ternary Systems in Aqueous Solution  [PDF]
S. A. A. Sajadi
Open Journal of Inorganic Non-metallic Materials (OJINM) , 2014, DOI: 10.4236/ojinm.2014.41001

The acidity and stability constants of M(Gly)1, M(Ttr)1, and M(Trp)1 M: Cu2+, Cu(Bpy2)2+, and Cu(Phen3)2+ complexes, were determined by potentiometric pH titration. It is shown that the stability of the binary Cu(L), (L: Gly, Ttr, and Trp) complex is determined by the basicity of the carboxylate group on one side and amino group on the other side. It is demonstrated that the equilibrium, Cu(Ha4)2+ + Cu(L) \"\"Cu(Har)(L) + Cu2+, is displacement due to the well known experience that mixed ligand complexes formed by a divalent 3d ion, a heteroaromatic N base and an O donor ligand possess increased stability. The stability constants of the 1:1 complexes formed between Cu2+, Cu(Bpy)2+ or Cu(Phen)2+

Adaptive Fuzzy Sliding Mode Controller for Grid Interface Ocean Wave Energy Conversion  [PDF]
Adel A. A. Elgammal
Journal of Intelligent Learning Systems and Applications (JILSA) , 2014, DOI: 10.4236/jilsa.2014.62006

This paper presents a closed-loop vector control structure based on adaptive Fuzzy Logic Sliding Mode Controller (FL-SMC) for a grid-connected Wave Energy Conversion System (WECS) driven Self-Excited Induction Generator (SEIG). The aim of the developed control method is to automatically tune and optimize the scaling factors and the membership functions of the Fuzzy Logic Controllers (FLC) using Multi-Objective Genetic Algorithms (MOGA) and Multi-Objective Particle Swarm Optimization (MOPSO). Two Pulse Width Modulated voltage source PWM converters with a carrier-based Sinusoidal PWM modulation for both Generator- and Grid-side converters have been connected back to back between the generator terminals and utility grid via common DC link. The indirect vector control scheme is implemented to maintain balance between generated power and power supplied to the grid and maintain the terminal voltage of the generator and the DC bus voltage constant for variable rotor speed and load. Simulation study has been carried out using the MATLAB/Simulink environment to verify the robustness of the power electronics converters and the effectiveness of proposed control method under steady state and transient conditions and also machine parameters mismatches. The proposed control scheme has improved the voltage regulation and the transient performance of the wave energy scheme over a wide range of operating conditions.

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