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Variability in Pathogenicity among Tunisian Isolates of Phytophthora cactorum as Measured by Their Ability to Cause Crown Rot on Four Apple Cultivars and MM106 Roostock
N. Boughalleb,A. Moulahi,M. El Mahjoub
Journal of Agronomy , 2006,
Abstract: Studies on two isolates of Phytophthora cactorum recovered from apple plants identified the presence of diversity in pathogenicity. These isolates appeared pathogenic to tested apple trees. It revealed that Golden Delicious, Star Crimson and the rootstock MM106 were more susceptible than Richared and Red Delicious cultivars, but with variable levels of aggressiveness according to physiological stages of tested segments of apple plants. Necrosis caused by Phytophthora cactorum isolates was more important on shoot segments than on wood segments.
Existence of infinitely many homoclinic orbits for second-order systems involving Hamiltonian-type equations
Adel Daouas,Ammar Moulahi
Electronic Journal of Differential Equations , 2013,
Abstract: We study the second-order differential system $$ ddot u + Adot{u}- L(t)u+ abla V(t,u)=0, $$ where A is an antisymmetric constant matrix and $L in C(mathbb{R}, mathbb{R}^{N^2})$. We establish the existence of infinitely many homoclinic solutions if W is of subquadratic growth as $|x| o +infty$ and L does not satisfy the global positive definiteness assumption. In the particular case where A=0, earlier results in the literature are generalized.
Fault-Tolerant Energy-Efficient Tree in Dynamic WSNs
Tarek Moulahi,Ahmed Almuhirat,Lamri Laouamer
International Journal of Ad Hoc, Sensor & Ubiquitous Computing , 2013, DOI: 10.5121/ijasuc.2013.420
Abstract: Broadcasting has a main importance in Wireless Sensor Networks (WSNs). Effectively, the sink node hasto collect periodically, data from the environmentsupervised by sensors. To perform this operation, itsends requests to all nodes. Furthermore, WSNs havea dynamic behaviour due to their evolution. At anytime, a node can be retrieved from the network dueto an exhausting energy or a node problem. In fact,WSNs are prone to failure such as software or hardware malfunctioning, exhaustion of energy,wireless interference and environmental hazards.Thus, an appropriate broadcasting method shouldtake into consideration this aspect and uses the less possible amount of energy to accomplish the task. Inthis paper, a robust tree-based scheme is proposedwhich is called Robust Tree Broadcasting (RTB). Thenew scheme has a load-balanced behaviour which induces an efficient use of energy. In addition, RTBhas a high-quality fault tolerant performance.
Learning to Match for Multi-criteria Document Relevance
Bilel Moulahi,Lynda Tamine,Sadok Ben Yahia
Computer Science , 2014,
Abstract: In light of the tremendous amount of data produced by social media, a large body of research have revisited the relevance estimation of the users' generated content. Most of the studies have stressed the multidimensional nature of relevance and proved the effectiveness of combining the different criteria that it embodies. Traditional relevance estimates combination methods are often based on linear combination schemes. However, despite being effective, those aggregation mechanisms are not effective in real-life applications since they heavily rely on the non-realistic independence property of the relevance dimensions. In this paper, we propose to tackle this issue through the design of a novel fuzzy-based document ranking model. We also propose an automated methodology to capture the importance of relevance dimensions, as well as information about their interaction. This model, based on the Choquet Integral, allows to optimize the aggregated documents relevance scores using any target information retrieval relevance metric. Experiments within the TREC Microblog task and a social personalized information retrieval task highlighted that our model significantly outperforms a wide range of state-of-the-art aggregation operators, as well as a representative learning to rank methods.
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
Abstract:

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
Abstract:

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
Abstract:

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.

Geochemical Characteristics and Chemical Electron Microprobe U-Pb-Th Dating of Pitchblende Mineralization from Gabal Gattar Younger Granite, North Eastern Desert, Egypt  [PDF]
Hassan A. A. Shahin
Open Journal of Geology (OJG) , 2014, DOI: 10.4236/ojg.2014.41003
Abstract:

Pitchblende mineralization was studied in the younger granite samples collected from Gabal Gattar, north Eastern Desert, Egypt using electron scanning microscope (ESM) and electron probe microanalyses (EPMA). This study revealed that this pitchblende contains significant Zr content reaching up to (66.80% ZrO2), which suggests that volcanic rocks were probably the source of such a deposit. High level emplaced high-K Calc-alkaline plutons as Qattar granite may have been associated with their volcanic equivalent emplaced in the surrounding area or now eroded. Lead content of the pitchblende mineralization is high and with moderate volcanics (up to 7.71% PbO). In contrast, it is low in ThO2, Y2O3 and REE2O3. High Zr and Pb content associated with pitchblende mineralization from Gattar granite indicates

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