Ahmed A.S.,Port Said University
Renewable and Sustainable Energy Reviews | Year: 2012
Egypt is one of the developing countries. The production of electricity in Egypt is basically on petroleum, natural gas, hydro-power and wind energy. The objective of this work to prove the availability of sufficient wind potential in the wide area of deep south Egypt for the operation of wind turbines there. Nevertheless, it gives in general an approximate profile which is useful to the wind parks design for this area. The data used in the calculation are published and analyzed for the first time. The diagrams of the measured wind data for three meteorological stations over a period of two years (wind speed, frequency, direction), wind shear coefficient, the mean monthly and annual wind speed profile for every location are presented. Monthly Weibull parameters, standard deviation and coefficient of variation have been statistically discussed. A comparison of the rose diagrams shows that the wind speed is more persistent and blow over this region of Egypt in two main sectors N and NNW with long duration of frequencies from 67% to 87% over the year with an average wind speed in the range 6.8-7.9 m/s at the three stations. Evaluation of monthly wind energy density at 10 m height by two different methods was carried out. And the final diagram for every site shows no significant difference between them. The annual natural wind energies at 70 m A.G.L. lie between 333 and 377 W/m 2 for Dakhla South and Kharga stations, respectively, which is similar to the inland wind potential of Vindeby (Denmark) and some European countries. These results indicate that Kharga and Dakhla South locations are new explored sites for future wind power generation projects. © 2011 Elsevier Ltd. All rights reserved.
Zubydan A.H.,Port Said University
Engineering Structures | Year: 2011
Frame elements may be subjected to significant bending moments about cross-sectional minor axis such as space frame elements and struts that buckle about minor axes. In some cases such as columns with compound cross-sections, the major bending moment acts about minor axes of cross-sectional components. The present paper proposes a simplified model for predicting the second order inelastic behavior of steel frame elements under axial compression force and bending moment about minor axis. New formulae are proposed to describe the plastic strength surface for steel I- and H-shaped cross-sections under axial force and bending moment about minor axis. Moreover, empirical formulae are developed to predict the tangent modulus for those cross-sections. The tangent modulus formulae are extended to evaluate the secant stiffness that is used for internal force recovery. The formulae are derived for steel sections considering the residual stresses as recommended by the European Convention for Construction Steelwork (ECCS). A finite element program is prepared to predict the inelastic second order behavior of plane frames using the derived formulae. The derived model exhibits good correlations when compared with the fiber model results. The analysis results indicate that the new model is accurate, furthermore it saves a lot of calculation time that may be consumed by iterations on the cross-sectional level. © 2011 Elsevier Ltd.
Geochemistry of the Neoproterozoic metasediments of Malhaq and Um Zariq formations, Kid metamorphic complex, Sinai, Egypt: Implications for source-area weathering, provenance, recycling, and depositional tectonic setting
El-Bialy M.Z.,Port Said University
Lithos | Year: 2013
The Um Zariq and Malhaq formations occupy roughly the northern half of the Kid metamorphic complex of SE Sinai, in the NE part of the Arabian-Nubian Shield. The Um Zariq Formation metasediments are relicts of an old sedimentary sequence (Cryogenian; 813±6Ma), whereas the Malhaq Formation records several phases of Ediacaran sedimentation and volcanic activity (615-607Ma). The Um Zariq Formation is mainly represented by well-bedded metapelitic schists, while the Malhaq Formation comprises a series of structureless to schistose felsic to intermediate metavolcanics interbedded with mica-rich phyllites and schists. The Um Zariq metasediments are depleted in SiO2, CaO and K2O and enriched in TiO2, Al2O3 and K2O relative to those of the Malhaq Formation. Aside from the relatively low Ni and Cr concentrations, compatible transition elements of these metasediments are comparable to average crustal contents. Except for marked Sr depletion, LILEs are around average continental crust values. Pronounced negative Nb-Ta anomalies and enrichment of Um Zariq samples in Th, U, Zr, Ti and Y relative to Malhaq ones are the main features of HFSEs. The REE patterns of all samples are parallel to sub-parallel LREE-enriched, with distinct negative Eu anomalies and weakly fractionated HREE segments. The source rocks of the Malhaq Formation metasediments underwent mild to moderate chemical weathering, whereas those of the Um Zariq Formation have suffered severe chemical weathering. These metasediments are predominately derived from felsic to intermediate igneous sources, with a particular slight addition from recycled sedimentary source to the Malhaq Formation metasediments. They are collectively geochemically immature and have suffered minor sedimentary recycling, with the experience of the Malhaq Formation metasediments from higher degree of sorting and reworking. The Malhaq and Um Zariq metasediments were originally deposited in a continental arc setting, most probably back-arc basin, despite the wide time span between their individual depositions. © 2013 Elsevier B.V.
Zubydan A.H.,Port Said University
Engineering Structures | Year: 2010
A simplified model for predicting second order inelastic behavior of steel frames is developed. New empirical formulae are developed to describe the tangent stiffness of steel sections subjected to an axial compression force and bending moment. The tangent stiffness formula is extended to evaluate the secant stiffness that is used for the internal force recovery. The formulae are derived for steel sections considering the residual stresses as recommended by the European Convention for Construction Steelwork (ECCS). The tangent stiffness for steel sections is also evaluated for the case where residual stresses are neglected. A finite element program is prepared to predict the inelastic second order behavior of plane steel frames using the derived formulae for the steel cross sections. The updated Lagrange coordinates are used to include the second order effect. The Newton-Raphson scheme combined with the minimum residual displacement method is employed to satisfy the equilibrium between external and internal forces. Comparisons with fiber model indicate good agreement with the present model. The analysis results indicate that the new model is accurate and has a faster rate of convergence for problems involving inelastic behavior. © 2010 Elsevier Ltd.
Hosny N.M.,Port Said University
Polyhedron | Year: 2011
This study focuses on the preparation and characterization of single phase NiO nano particles. Four nickel anthranilic acid complexes were synthesized by the semi-solid phase reaction method as precursors for the preparation of NiO nanoparticles via a solid-state decomposition procedure at 700 °C. Thermogravimetric analysis (TGA) was applied to determine the thermal behavior of the precursors and the temperature at which the precursors decompose leaving the oxide. The crystalline structures of the products were investigated by X-ray diffraction (XRD), the morphology of particles by SEM and TEM. The particles size was determined by STM, and the average particle size was found to be 8 nm. Electronic spectra were used to clarify qualitatively the change in absorption band positions on changing the particle size of NiO. The optical band gap of the NiO nanoparticles was calculated and indicated a direct transition. The values of the optical band gap of NiO nanoparticles increase as the particle size decreases.© 2010 Elsevier Ltd. All rights reserved.