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Search Results: 1 - 10 of 401432 matches for " M. Boudalia "
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The role of the Umayyad authority in supporting and encouraging industrial activity in Andalusia Through the centuries (3-4 AH / 9-10 AD)
Boudalia Touatia
Historical Kan Periodical , 2011,
Abstract: . . (3-4 /9-10 ) . . .
Actualization of Power and Society to The Craftsmen and Artisans in Andalusia :
Boudalia Touatia
Historical Kan Periodical , 2011,
Abstract: . 3- 4 / 9 -10 . .
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
Study of Duct Characteristics Deduced from Low Latitude Ground Observations of Day-Time Whistler at Jammu  [PDF]
M. Altaf, M. M. Ahmad
International Journal of Astronomy and Astrophysics (IJAA) , 2013, DOI: 10.4236/ijaa.2013.33032
Abstract:

Propagation characteristics of low latitude whistler duct characteristics have been investigated based on day-time measurements at Jammu. The morphogical characteristics of low latitude whistlers are discussed and compared with characteristics of middle and high latitude whistlers. The Max. electron density (Nm) at the height of the ionosphere obtained from whistler dispersion comes out to be higher than that of the background which is in accordance with the characteristics of whistler duct. The equivalent width is found to be close to the satellite observations and the characteristics of whistler duct in low latitude ionosphere are similar to those in middle and high latitude ionosphere. The width of ducts estimated from the diffuseness of the whistler track observed during magnetic storm is found to lie in the range of 50 - 200 Km.

Review Article: Immobilized Molecules Using Biomaterials and Nanobiotechnology  [PDF]
Magdy M. M. Elnashar
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2010, DOI: 10.4236/jbnb.2010.11008
Abstract: Immobilized molecules using biomaterials and nanobiotechnology is a very interesting topic that touching almost all aspects of our life. It uses the sciences of biology, chemistry, physics, materials engineering and computer science to develop instruments and products that are at the cutting edge of some of today’s most promising scientific frontiers. In this review article, the author based on his experience in this arena has tried to focus on some of the supports for im-mobilization; the most important molecules to be immobilized such as DNA, cells, enzymes, metals, polysaccharides, etc and their applications in medicine, food, drug, water treatment, energy and even in aerospace. He specified a special section on what is new in the arena of supports and technologies used in enzyme immobilization and finally a recommendation by the author for future work with a special attention to up-to-date references.
Using of the generalized special relativity (GSR) in estimating the neutrino masses to explain the conversion of electron neutrinos  [PDF]
M. H. M. Hilo
Natural Science (NS) , 2011, DOI: 10.4236/ns.2011.34044
Abstract: In this work the Generalized Special Relativity (GSR) is utilized to estimate masses of some elementary particles such as, neutrinos. These results are found to be in conformity with experimental and theoretical data. The results obtained may explain some physical phenomena, such as, conversion of neutrinos from type to type when solar neutrino reaches the Earth.
Postischemic Lower Extremity Wounds Treated with and without Negative Pressure Dressing  [PDF]
Naz?mmü?
Surgical Science (SS) , 2012, DOI: 10.4236/ss.2012.37075
Abstract: Background: Vacuum-assisted dressing is a noninvasive closure system of the wound, which makes localized and controlled negative pressure. Its mechanical tension reduces edema, stimulates granulation tissue formation and angiogenesis, and prepares the wound bed for closure. In this study, a patient has been presented, who suffered from serious lower extremity wounds due to arterial emboli, one of her wounds has been treated with vacuum-assisted dressing and the other with conventional dressing to evaluate the efficacy of vacuum-assisted dressing in acute ischemic wounds. Methods: A 65-year-old female patient was admitted to the emergency clinic, due to complaint of severe pain in her right lower extremity which suggested an acute arterial occlusion. She immediately underwent an embolectomy operation; however, a few days later, severe ischemia on the leg and foot became appearant. All of the necrosis was sharply debrided under sterile conditions in the operating room, and then lower leg wound was covered with vacuum-assisted dressing, also calcaneal wound was dressed with silver sulphadiazine. Results: Eighteen days after the first dressing with negative pressure, distal leg wound became ready for closure, whereas, enough granulation tissue over the calcaneal area developed merely thirty-four days later. Calcaneal wound closed spontaneously within fifty-three days. Conclusions: When dealing with this experience, using the negative pressure dressing in patient with severe lower limb wounds following arterial emboli, accelerates wound healing by means of developing the granulation tissue, and rapidly prepares the wound for closure, so it may reduce the risk of amputation.
Laplace Transform Method for Unsteady Thin Film Flow of a Second Grade Fluid through a Porous Medium  [PDF]
M. Ali, M. Awais
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.53017
Abstract:

In this article, we have effectively used the Numerical Inversion of Laplace transform to study the time-dependent thin film flow of a second grade fluid flowing down an inclined plane through a porous medium. The solution to the governing equation is obtained by using the standard Laplace transform. However, to transform the obtained solutions from Laplace space back to the original space, we have used the Numerical Inversion of Laplace transform. Graphical results have been presented to show the effects of different parameters involved and to show how the fluid flow evolves with time.

An Integral Collocation Approach Based on Legendre Polynomials for Solving Riccati, Logistic and Delay Differential Equations  [PDF]
M. M. Khader, A. M. S. Mahdy, M. M. Shehata
Applied Mathematics (AM) , 2014, DOI: 10.4236/am.2014.515228
Abstract:

In this paper, we propose and analyze some schemes of the integral collocation formulation based on Legendre polynomials. We implement these formulae to solve numerically Riccati, Logistic and delay differential equations with variable coefficients. The properties of the Legendre polynomials are used to reduce the proposed problems to the solution of non-linear system of algebraic equations using Newton iteration method. We give numerical results to satisfy the accuracy and the applicability of the proposed schemes.

ДОСЛ ДЖЕННЯ АНАЛ ТИЧНОГО МЕТОДУ ОЦ НЮВАННЯ ЙМОВ РНОСТ ПОТЕНЦ ЙНО КОНФЛ КТНИХ СИТУАЦ Й В ПОВ ТРЯНОМУ РУС The study of the analytical method of evaluating the probability of potential conflict situations in air traffic Исследование аналитического метода оценки вероятности потенциально конфликтных ситуаций в воздушном движении
В.M. Василь?в
Proceedings of National Aviation University , 2007,
Abstract: Розглянуто застосування запропонованого ран ше методу оц нювання ймов рност потенц йних конфл кт в для системи керування пов тряним рухом. Досл джено властивост методу, наведено проанал зовано результати комп’ютерного моделювання. Application of the method of potential conflicts probability evaluation offered before for air traffic control system is considered. The properties of the method are investigated, results of computer modeling are represented and analyzed. Рассмотрено применение предложенного ранее метода оценки вероятности потенциальных конфликтов для системы управления воздушным движением. Исследованы свойства метода, приведены и проанализированы результаты компьютерного моделирования.
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