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Search Results: 1 - 10 of 223900 matches for " R. Ayad "
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Mean Square Solutions of Second-Order Random Differential Equations by Using the Differential Transformation Method  [PDF]
Ayad R. Khudair, S. A. M. Haddad, Sanaa L. Khalaf
Open Journal of Applied Sciences (OJAppS) , 2016, DOI: 10.4236/ojapps.2016.64028
Abstract: The differential transformation method (DTM) is applied to solve the second-order random differential equations. Several examples are represented to demonstrate the effectiveness of the proposed method. The results show that DTM is an efficient and accurate technique for finding exact and approximate solutions.
Synthesis, Characterization and Metal Ion Chelating Efficiency of an Environment-Friendly Copolymers Containing Dithio Formic Acid and Thiosemicarbazide or 1,2,4-Triazole Group  [PDF]
Ayad Hameed
International Journal of Organic Chemistry (IJOC) , 2013, DOI: 10.4236/ijoc.2013.31002
Abstract:

Six phenolic monomers (M1 - M6) have been synthesized, namely, potassium-3-(ortho,para)-hydroxy benzoyl dithiofor- mate (M1 and M2), (ortho,para)-(4-amino-5-mercapto-1,2,4 triazol-3-yl)-phenol (M3 and M4), (ortho,para)-hydroxy benzoic acid thiosemicarbazide (M5 and M6) and twelve novel chelating terpolymers (P1 - P12) were synthesized by ter- polymerization condensation reaction of these monomers with phenol or bis phenol-A and excess of formalin in basic medium. The monomers (M1 - M6) and their co-polymers (P1 - P12) were characterized by FT.IR, H1-NMR, elemental analysis and thermal analysis (TGA) and according to data obtained the structures of these compounds were proposed. Analytical evaluation of chelating selectivity of these polymers toward (Co2+, Cr3+, Cu2+, Cd2+, Pb2+) were achieved by batch equilibrium method, the results show that all synthetic resins have high efficiency toward (Cr3+) and less effi- ciency toward (Co2+, Cu2+, Cd2+ and Pb2+).

 

Developing an Automated Land Cover Classifier Using LiDAR and High Resolution Aerial Imagery  [PDF]
Yasser M. Ayad
Journal of Geoscience and Environment Protection (GEP) , 2016, DOI: 10.4236/gep.2016.47011
Abstract: The aim of this project is to create high resolution land cover classification as well as tree canopy density maps at a regional level using high resolution spatial data. Modeling and the data manipulation and analysis of LiDAR LAS point cloud dataset as well as multispectral aerial photographs from the National Agriculture Imagery Program (NAIP) were carried out. Using geoprocessing modeling, a land cover map is created based on filtered returns from LiDAR point cloud data (LAS dataset) to extract features based on their class and return values, and traditional classification methods of high resolution multi-spectral aerial photographs of the remaining ground cover for Clarion County in Pennsylvania. The newly developed model produced 7 classes at 10 ft × 10 ft spatial resolution, namely: water bodies, structures, streets and paved surfaces, bare ground, grassland, trees, and artificial surfaces (e.g. turf). The model was tested against areas with different sizes (townships and municipalities) which revealed a classification accuracy between 94% and 96%. A visual observation of the results shows that some tree-covered areas were misclassified as built up/structures due to the nature of the available LiDAR data, an area of improvement for further studies. Furthermore, a geoprocessing service was created in order to disseminate the results of the land cover classification as well as the tree canopy density calculation to a broader audience. The service was tested and delivered in the form of a web application where users can select an area of interest and the model produces the land cover and/or the tree canopy density results (http://maps.clarion.edu/LandCoverExtractor). The produced output can be printed as a final map layout with the highlighted area of interest and its corresponding legend. The interface also allows the download of the results of an area of interest for further investigation and/or analysis.
Using Colloidal Nano Silica to Enhance the Performance of Cementitious Mortars  [PDF]
Achraf Ayad, Aly Said
Open Journal of Civil Engineering (OJCE) , 2018, DOI: 10.4236/ojce.2018.81007
Abstract: Nanomaterials have been widely used in the past few decades due to their proven capacity to enhance the mechanical properties of materials. While many studies have sought to improve the understanding of how nanomaterials affect the behavior of concrete, additional research is needed in order to achieve the full potential of the material, especially in the presence of supplementary cementitious materials. This study aims to investigate the mechanical properties of cement mortars incorporating both nano-silica (NS) and class F fly ash (FA). Furthermore, mercury intrusion porosimetry (MIP) was performed to study its effect on pore characteristics, and thermogravimetric analysis (TGA) was performed to measure the calcium hydroxide Ca(OH)2 content in the mixtures. It was found that using nano-silica enhances the compressive strength, reduces the total porosity and accelerates the pozzolanic reaction.
An Axisymmetric Hyperelastic Solid Model for Forming Processes of Hollow Plastic Bodies
T. Ghomari,N. Talbi,R. Ayad,D. Kerdal
Journal of Applied Sciences , 2006,
Abstract: This work deals with the non-linear formulation of 4-node axisymmetric hyperelastic solid model, based on the concept of SFR (Space Fiber Rotation). The SFRaxi model uses the kinematics of a space fibre to obtain an enriched displacement field. It improves in a significant way the precision of the classical 4-node axi- symmetrical element Q4axi. The corresponding results are comparable and even better in term of time CPU, with those of the higher order Q8axi element. A hyperelastic behaviour law based on the Mooney-Rivlin approach has been implemented allowing better simulations of blow-moulding and thermoforming of hollow plastic bodies. The numerical results, very promising, are mainly focused on some plastic forming tests without contact (swellings).
On the Riccatti differential polynomials
A. Ayad
ACTA MATHEMATICA UNIVERSITATIS COMENIANAE , 2010,
Abstract: We present in this paper some properties of the Riccatti differential polynomial associated with a homogeneous linear ordinary differential equation. We give a complete description of the differential Newton polygons of its derivatives and its evaluations.
On the Riccatti differential polynomials
A. Ayad
ACTA MATHEMATICA UNIVERSITATIS COMENIANAE , 2010,
Abstract: We present in this paper some properties of the Riccatti differential polynomial associated with a homogeneous linear ordinary differential equation.We give a complete description of the differential Newton polygons of its derivatives and its evaluations.
On the complexity of solving ordinary differential equations in terms of Puiseux series
Ali Ayad
Mathematics , 2007,
Abstract: We prove that the binary complexity of solving ordinary polynomial differential equations in terms of Puiseux series is single exponential in the number of terms in the series. Such a bound was given by Grigoriev [10] for Riccatti differential polynomials associated to ordinary linear differential operators. In this paper, we get the same bound for arbitrary differential polynomials. The algorithm is based on a differential version of the Newton-Puiseux procedure for algebraic equations.
A note on the computation of Puiseux series solutions of the Riccatti equation associated with a homogeneous linear ordinary differential equation
Ali Ayad
Mathematics , 2008,
Abstract: We present in this paper a detailed note on the computation of Puiseux series solutions of the Riccatti equation associated with a homogeneous linear ordinary differential equation. This paper is a continuation of [1] which was on the complexity of solving arbitrary ordinary polynomial differential equations in terms of Puiseux series.
Pharmacokinetics and Efficacy of Tilmicosin in the Treatment of Pasteurella haemolytica Bronchopneumonia in Calves  [PDF]
Ahmed M. Soliman, Amer Ramadan Ali Ayad
Pharmacology & Pharmacy (PP) , 2014, DOI: 10.4236/pp.2014.55061
Abstract:

Tilmicosin was administered intravenously and subcutaneously at a dose rate of 10 mg/kg bwt to determine its concentration in blood and bronchial secretion as well as its kinetic behavior in healthy and Pasteurella haemolytica type A1-infected calves. Sever acute bronchopneumonia was induced in 10 calves by inoculating them intra-tracheally with P. haemolytica type A1. The calves were treated with tilmicosin; 5 of these received the drug intravenously and the other 5 were injected subcutaneously. After a slow intravenous injection, the serum concentration-time curve indicated a two compartment open model with a mean elimination half-lives (t1/2bs) of 22.09 and 22.14 hours before and after infection, respectively. The mean residence time (MRT) corrected for a bolus injection was 2.25 and 2.20 hours and the mean MRTinf was 25.27 and 25.46 hours in healthy and P. haemolytica-infected calves, respectively. After subcutaneous injection, the drug was eliminated more slowly (before and after infection) from serum and bronchial secretions, with t1/2bs of (24.60 and 25.85 hours) and (33.74 and 31.78 hours), respectively. The apparent volume of distribution (V

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