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Search Results: 1 - 10 of 8054 matches for " Asmaa Nabil-Adam "
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Assessment of Secondary Metabolites from Marine-Derived Fungi as Antioxidant  [PDF]
Nihad Abdel-Monem, Ahmed M. Abdel-Azeem, E. S. H. El Ashry, Doaa A. Ghareeb, Asmaa Nabil-Adam
Open Journal of Medicinal Chemistry (OJMC) , 2013, DOI: 10.4236/ojmc.2013.33009
Abstract:

Marine derived fungi are considered as a promising source of novel drugs due to their biodiversity and consequent chemo-diversity. Although marine microorganisms especially fungi are not well defined taxonomically, making this a promising frontier for the discovery of new medicines. This study focused on marine derived fungi as a model for bioactive exploration for new entities with anti-inflammatory and antioxidant capacity. Three in-vitro assays were used to investigate the bioactive antioxidant potentiality of fungal extracts. Thiobarbituric acid (TBARS),α,α-Diphenyl-β- picrylhydrazyl (DPPH) and NO assay are based on their total phenolic and flavonoid content of each extract group. Ch. globosum recorded the highest antioxidant activity (92.82%) in TBARS assay, while G. dankaliensis came first by recording 59.28% in DPPH assay in comparison with ascorbic acid (61.83%). In NO inhibition assay, N. oryzae showed 49.3% comparing with ascorbic acid (73.12%). From the preliminary result of our extracts, we can consider the marine derived fungi extracts as

Improving Rule Base Quality to Enhance Production Systems Performance  [PDF]
Nabil Arman
International Journal of Intelligence Science (IJIS) , 2013, DOI: 10.4236/ijis.2013.31001
Abstract: Production systems have a special value since they are used in state-space searching algorithms and expert systems in addition to their use as a model for problem solving in artificial intelligence. Therefore, it is of high importance to consider different techniques to improve their performance. In this research, rule base is the component of the production system that we aim to focus on. This work therefore seeks to investigate this component and its relationship with other components and demonstrate how the improvement of its quality has a great impact on the performance of the production system as a whole. In this paper, the improvement of rule base quality is accomplished in two steps. The first step involves re-writing the rules having conjunctions of literals and producing a new set of equivalent rules in which long inference chains can be obtained easily. The second step involves augmenting the rule base with inference short-cut rules devised from the long inference chains. These inference short-cut rules have a great impact on the performance of the production system. Finally, simulations are performed on randomly generated rule bases with different sizes and goals to be proved. The simulations demonstrate that the suggested enhancements are very beneficial in improving the performance of production systems.
Parallel Graph Transformation based on Merged Approach
Asmaa Aouat
IAES International Journal of Robotics and Automation (IJRA) , 2013, DOI: 10.11591/ijra.v2i2.1610
Abstract: Graph transformation is one of the key concepts in graph grammar. In order to accelerate the graph transformation, the concept of parallel graph transformation has been proposed by different tools such as AGG tool. The theory of parallel graph transformation used by AGG just allows clarifying the concepts of conflict and dependency between the transformation rules. This work proposes an approach of parallel graph transformations which enables dependent transformation rules to be executed in parallel.
Energy-Efficient and Coverage-Aware Clustering in Wireless Sensor Networks  [PDF]
Fahed Awad, Eyad Taqieddin, Asmaa Seyam
Wireless Engineering and Technology (WET) , 2012, DOI: 10.4236/wet.2012.33021
Abstract: Energy efficiency and sensing coverage are essential metrics for enhancing the lifetime and the utilization of wireless sensor networks. Many protocols have been developed to address these issues, among which, clustering is considered a key technique in minimizing the consumed energy. However, few clustering protocols address the sensing coverage metric. This paper proposes a general framework that addresses both metrics for clustering algorithms in wireless sensor networks. The proposed framework is based on applying the principles of Virtual Field Force on each cluster within the network in order to move the sensor nodes towards proper locations that maximize the sensing coverage and minimize the transmitted energy. Two types of virtual forces are used: an attractive force that moves the nodes towards the cluster head in order to reduce the energy used for communication and a repulsive force that moves the overlapping nodes away from each other such that their sensing coverage is maximized. The performance of the proposed mechanism was evaluated by applying it to the well-known LEACH clustering algorithm. The simulation results demonstrate that the proposed mechanism improves the performance of the LEACH protocol considerably in terms of the achieved sensing coverage, and the network lifetime.
Approximate Solution of Lane-Emden Type Equations Using Variation of Parameters Method with an Auxiliary Parameter  [PDF]
Asmaa S. Khalifa, Hany N. Hassan
Journal of Applied Mathematics and Physics (JAMP) , 2019, DOI: 10.4236/jamp.2019.74062
Abstract: Lane-Emden type equation is a nonlinear differential equation appears in many fields such as stellar structure, radioactive cooling and modeling of clusters of galaxies. In this work, this equation is investigated using a semi-analytical method called the Variation of parameters method with an auxiliary parameter. In the applied technique, an unknown auxiliary parameter is inserted in Variation of Parameters Method to solve some special cases of these equations. The used algorithm is easy to implement and very effective. The obtained solutions are also fairly accurate.
Product Ethnicity between the Hammer of Identity and the Anvil of Globalization  [PDF]
Jeddi Nabil, Zaiem Imed
American Journal of Industrial and Business Management (AJIBM) , 2013, DOI: 10.4236/ajibm.2013.31011
Abstract:

With the globalization of markets, the multinational production made obvious great strides marked by the proliferation of hybrid or bi-national products. In this context which supported the dissolution of identity of several products’ categories and called in question the weight of origin labels about the consumer behavior purchase. Beyond these reflections, this article proposed to wonder about the relation between globalization and product ethnicity, by analyzing the apparent effects of the current context of globalization on the establishment of stereotypic country-products associations by the consumers. Also, the question which is directed to the development and the presentation of this research is the following one: to what extend does the current context of globalization enable us to call in question the phenomenon of product ethnicity?

On Slide Mode Control of Chaotic Rikitake Two-Disk Dynamo—Chaotic Simulations of the Reversals of the Earth’s Magnetic Field  [PDF]
Ahmad Harb, Nabil Ayoub
International Journal of Modern Nonlinear Theory and Application (IJMNTA) , 2014, DOI: 10.4236/ijmnta.2014.33015
Abstract:

The modern nonlinear theory, bifurcation and chaos theory are used in this paper to analyze the dynamics of the Rikitake two-disk dynamo system. The mathematical model of the Rikitake system consists of three nonlinear differential equations, which found to be the same as the mathematical model of the well-known Lorenz system. The study showed that under certain value of control parameter, the system experiences a chaotic behaviour. The experienced chaotic oscillation may simulate the reversal of the Earth’s magnetic field. The main objective of this paper is to control the chaotic behaviour in Rikitake system. So, a nonlinear controller based on the slide mode control theory is designed. The study showed that the designed controller was so effective in controlling the unstable chaotic oscillations.

A Model for FeSiMg Alloy Production by Reduction Technique  [PDF]
Saeed Nabil Saeed Ghali
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2011, DOI: 10.4236/jmmce.2011.109067
Abstract: Ferrosilicon magnesium is basic foundry alloys used for the production of ductile cast iron. Magnesium content plays an important role in the produced alloy grades from dolomite ore. The focus of the present work is to simulate mathematical model to predict magnesium content in the ferrosilicon magnesium, which produced by silicothermic reduction of calcined dolomite. The basic assumptions of this model are: constant low viscosity of molten charge, the reaction is irreversible of second order and the reaction is isothermal. The reaction is based on the following equation: 2MgO+2Si →Mg2Si+SiO2 The results of previous work was found to be in a good coincidence with the predicted values by the model [Mg]=(MgO0)[Si0][eKt[(MgO0)-[Si0]]-1]/ (MgO0)[eKt[(MgO0)-[Si0]]-[Si0]] where [Mg] is the concentration of magnesium metal in ferrosilicon magnesium alloy in mol/L. [Si0] and (MgO0) are the initial concentration of silicon and magnesium oxide in charge in mol/L, while t is time in second, K is the reaction rate constant ( 3.26588x10-7 L Sec-1 mol-1). The predicted values are greater than the experimental values; this may be attributed to the use of concentration instead of the activity. The predicted values of magnesium content in ferrosilicon magnesium alloy are in a good agreement with the experimental results obtained in previous work at low viscosity.
Mechanisms of the Deterioration of the Wall Reliefs at Shenhur Temple, Upper Egypt and Concepts for Conservation  [PDF]
Nabil A. Bader
Open Journal of Geology (OJG) , 2015, DOI: 10.4236/ojg.2015.511071
Abstract: The Roman Period temple of Isis at Shenhur was built and enhanced amid the rule of Augustus (30 BCE-14 CE) through that of Trajan (98-117 CE). It was built of two sorts of local limestone and decorated with reliefs. Examination of conservation state uncovered that it was collapsed and only partly preserved and it disposed of some still buried rooms. The temple is exposed to different deteriorations processes created by internal and external stresses because of the mineral composition of the building materials, atmosphere variables, salts crystallization and groundwater. In this study, the deterioration problems of the wall reliefs were examined for the aim of its conservation. For this purpose, the chemical, physical and structural characterization were performed by means of X-Ray Diffraction (XRD) and observation of thin section by transmitted light optical microscopy (LOM), polarized microscope, Scanning Electron Microscope (SEM) attached with EDX and thermogravimetric (DTA & TGA). Additionally, microbiological study and chemical analyses of ground water were carried out. Results demonstrated that the deterioration of Shenhur was because of the forceful activity of the environment agents and soluble salts such as chlorides and sulphates. These results and information allowed that the identification of the types of salts and deterioration features might be used in the future for conservation purposes.
The Use of Genetic Approach to the Kinematics of Cutting  [PDF]
Nabil Wanas Musa
World Journal of Mechanics (WJM) , 2016, DOI: 10.4236/wjm.2016.610028
Abstract: This article deals with the use of an interdisciplinary approach to modelling and creation of a complex technical system of different physical nature in relation to the kinematics of cutting and shaping. The professor of the National Technical University of Ukraine, Kuznetcov Iu. N., proposed the approach based on generalization of knowledge, methodological basis of which is the theory of evolution of the systems and methods of genetic analysis and synthesis. For generalization of the knowledge in the fundamental sciences is based on the principles of a limited number of elementary generic structures with the introduction of the gene concept. The modelling and synthesis of kinematic cutting schemes are providing the efficiency and viability of genetic and morphological approach. The material point, which can interact with other ma-terial points in space and time, simulating anthropogenic system of different origin, is introduced as a material object.
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