South Valley University
Aswan, Egypt

South Valley University is in Egypt and provides teaching and research facilities. The Aswan Power Electronics Applications Research Center is a research center of this university. Wikipedia.

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Khalifa M.,South Valley University
European Journal of Mechanics, A/Solids | Year: 2015

Flügge's shell theory and solution for the vibration analysis of a non-homogeneous orthotropic elliptical cylindrical shell resting on a non-uniform Winkler foundation are presented. The theoretical analysis of the governing equations of the shell is formulated to overcome the mathematical difficulties of mode coupling of variable curvature and homogeneity of shell. Using the transfer matrix of the shell, the vibration equations based on the variable Winkler foundation are written in a matrix differential equation of first order in the circumferential coordinate and solved numerically. The proposed model is applied to get the vibration frequencies and the corresponding mode shapes of the symmetrical and antisymmetrical vibration modes. The sensitivity of the vibration behavior and bending deformations to the non-uniform Winkler foundation moduli, homogeneity variation, elliptical and orthotropy of the shell is studied for different type-modes of vibrations. © 2014 Elsevier Masson SAS.

Din K.S.,South Valley University
Science of the Total Environment | Year: 2011

The concentration of 210Po was determined in different foodstuffs of plant origin purchased from markets in Qena City, Upper Egypt. Measurement of 210Po has been carried out using alpha spectrometry technique in different food categories such as vegetables, fruits, cereals beverages and herbs. The general range of 210Po activity levels ranged widely from <0.010-18.6±0.910mBqg-1, with minimum being in cereal samples and maximum being in beverage samples. Tea samples recorded highest activity concentrations of 210Po with lowest value of 10±0.54 mBqg-1 for Crown tea and highest value of 18.6±0.910mBqg-1 for El maabad tea. The daily intake of 210Po from food consumption reveals that vegetables are the biggest contributors, while beverages are the lowest. The effective ingestion dose has been estimated for Qena City residents and it was found in the range 0.008-38.3μSvy-1. © 2011 Elsevier B.V.

This study includes tailing from gold mine, at Allaqi Wadi Aswan, Egypt, used by incident Egyptian and after by some English companies. Tailings, soils and wild plants (Acia Raddiena and Aerva Javanica) were sampled and analysed for toxic metals (Hg, Cd, Pb and As) and associated heavy metals (Cr, Ag, Ni, Au, Mo, Zn, Mn and Cu) using ICP-MS, ICP-AES, CVAAS and FAAS techniques. The present work concerns the distribution and mobility of these metals from tailing to the surrounding soils and wild flora. The results reveal that Cr, Cu, Zn, Ni, Ag, Au, Mn, Hg, As, Ag, Au and Pb in soil decreased as faraway from the tailing, after then irregular trends as a result of input from surrounding rocks. Acia Raddiena plant accumulated As, Cd and Pb in higher levels than Aerva Javanica. Quantification of soil and plant pollution was studied using enrichment factors, contamination factor, pollution index and bioaccumulation factors and show good interpretations of the results. The overall results of this study show that the soil and plants near the gold mine tailing were highly toxic, and the plants and soil must not be uses for grazing or agriculture. © 2010 Elsevier B.V.

Awadalla E.A.,South Valley University
Experimental and Toxicologic Pathology | Year: 2012

Paraquat has been demonstrated to be a highly toxic compound for humans and animals and many cases of acute poisoning and death have been reported over the past few decades. The current experiment aimed to examine if vitamin C (ascorbic acid) alleviates the morphological changes induced by paraquat (PQ) administration in the liver and kidney of male albino rats. Male adult rats received paraquat (PQ) (1.5. mg/kg body weight) daily for three weeks. Vitamin C (VC) at a dose of 20. mg/kg body weight was given concomitantly with PQ to rats. Animals were divided into three groups in this experiment (control, PQ and PQ. +. VC). The morphopathological manifestations were investigated in tissues from liver and kidney. As expected, PQ administration induced marked changes in the morphological structure of the liver and kidney in PQ demonstrated animals. Importantly, vitamin C administration restored PQ-induced changes in the studied organs. Vitamin C administration attenuated the morphological damages induced by PQ in the liver and kidney of experimental animals. Our results suggest an antitoxic effect of vitamin C against paraquat. © 2010 Elsevier GmbH.

Mahdy A.,South Valley University
Nuclear Engineering and Design | Year: 2012

The term of nanofluid refers to a solid-liquid mixture with a continuous phase which is a nanometer sized nanoparticle dispersed in conventional base fluids. A numerical analysis has been presented to investigate the unsteady mixed convection boundary layer flow and heat transfer due to uncertainties of thermal conductivity and dynamic viscosity of nanofluid over a stretching vertical surface. The unsteadiness in the flow and temperature fields is caused by the time-dependent of the stretching velocity and the surface temperature. The governing partial differential equations with the auxiliary conditions are converted to ordinary differential equations with the appropriate corresponding conditions via scaling transformations. Different water-based nanofluids containing Cu, Ag, CuO, Al 2O 3, and TiO 2 are taken into consideration. The effects of pertinent parameters such as the solid volume fraction of nanoparticles, Prandtl number, mixed convection parameter, and the unsteadiness parameter have been discussed. Furthermore, different models of nanofluid based on different formulas for thermal conductivity and dynamic viscosity on the flow and heat transfer characteristics is discussed. Comparison with known results for steady state flow is presented and it found to be in excellent agreement. © 2012 Elsevier B.V.

The prototropic tautomerism in four novel azo compounds derived from pyrazolo[1,5-a]pyrimidin-7(4H)-one was intensively examined. Tautomeric structures which result from annular and azo-hydrazone tautomerism were exposed to semiempirical and density functional theory (DFT) calculations, allowing the recording of structural parameters, physicochemical properties and equilibrium constants to be recorded. The values of the equilibrium constants determined among the most stable forms clearly showed that compounds 1 and 2 co-exist in the NH and hydrazone forms. However, NH tautomers were strongly preferred to other forms in compounds 3 and 4. The observed electronic absorption bands were assigned and compared with the predicted transitions using a time-dependent DFT method (TDDFT). In all solvents employed, except for DMF and acetonitrile, compounds 1 and 2 exhibited azo-hydrazone tautomerism. However, the ionized species were predominant in highly polar solvents for compounds 3 and 4. In DMF, all the investigated dyes exist either in acid-base equilibrium or in the ionized form depending on the molecular structure. Hence, the values of the ionization constant (Kion) and Gibbs free energy (ΔG) of the equilibrium existing in solution were calculated. In addition, the pK a values of the investigated dyes were determined spectrophotometrically. © 2011 Elsevier Ltd. All rights reserved.

A non-similar boundary layer analysis is presented to study the flow, heat and mass transfer characteristics of non-Darcian mixed convection of a non-Newtonian fluid from a vertical isothermal plate embedded in a homogeneous porous medium with the effect of Soret and Dufour and in the presence of either surface injection or suction. The value of the mixed-convection parameter lies between 0 and 1. In addition, the power-law model is used for non-Newtonian fluids with exponent n< 1 for pseudoplastics n= 1 for Newtonian fluids and n> 1 for dilatant fluids. Furthermore, the coordinates and dependent variables are transformed to yield computationally efficient numerical solutions that are valid over the entire range of mixed convection, from the pure forced-convection limit to the pure free-convection limit, and the whole domain of non-Newtonian fluids, from pseudoplastics to dilatant fluids. The numerical solution of the problem is derived using a Runge-Kutta integration scheme with Newton-Raphson shooting technique. Distributions for velocity, temperature and concentration, as well as for the rate of wall heat and mass transfer, have been obtained and discussed for various physical parametric values. © 2010 Elsevier B.V.

This work is focused on the study of combined heat and mass transfer on double-diffusive convection near a vertical truncated cone in a fluid-saturated porous medium in the presence of a first-order chemical reaction and heat generation or absorption with variable viscosity. The viscosity of the fluid is assumed to be an inverse linear function of the temperature. A boundary layer analysis is employed to derive the non-dimensional non-similar governing equations. The governing equations for this investigation are formulated and solved numerically using the fourth-order Runge-Kutta integration scheme with Newton-Raphson shooting technique. Comparisons with previously published work on special cases of the problem are performed and found to be in excellent agreement. A parametric study illustrating the influence of chemical reaction parameter, heat generation or absorption parameter, viscosity-variation parameter, buoyancy ratio and Lewis number on the fluid velocity, temperature, concentration as well as Nusselt number and Sherwood number is conducted. The results of this parametric study are shown graphically and the physical aspects of the problem are highlighted and discussed. © 2010 Elsevier Ltd.

The effect of arbuscular mycorrhizal (AM) fungi inoculation on pepper (Capsicum annuum L. cv. Zhongjiao 105) plant growth and on some physiological parameters in response to increasing soil Cu concentrations was studied. Treatments consisted of inoculation or not with Glomus mosseae and the addition of Cu to soil at the concentrations of 0 (control), 2 (low), 4 (medium), and 8 (high) mM CuSO4. AM fungal inoculation decreased Cu concentrations in plant organs and promoted biomass yields as well as the contents of chlorophyll, soluble sugar, total protein, and the concentrations of P, K, Ca, and Mg. Plants grown in high Cu concentration exhibited a Cu-induced proline accumulation and also an increase in total free amino acid contents; however, both were lower in mycorrhizal pepper. Cu-induced oxidative stress by increasing lipid peroxidation rates and the activity of superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase, and AM symbiosis enhanced these antioxidant enzyme activities and decreased oxidative damage to lipids. In conclusion G. mosseae was able to maintain an efficient symbiosis with pepper plants in contaminated Cu soils, improving plant growth under these conditions, which is likely to be due to reduced Cu accumulation in plant tissues, reduced oxidative stress and damage to lipids, or enhanced antioxidant capacity. © 2011 Springer-Verlag.

Akawy A.,South Valley University
Arabian Journal of Geosciences | Year: 2015

The Um Had area, central Eastern Desert, Egypt shows a regional stretching in the NW–SE and a contraction in the NE–SW direction. Major NW–SE folds, small recumbent folds, and local thrusts and reverse faults were recognized. Complicated relation between folds and boudinage was identified. This stretching amount ranges from 1.282 to 1.309. Earlier coaxial and later non-coaxial strains were inferred. The change from axial to non-coaxial stress regime was gradual and the latter was associated with minor clockwise and anticlockwise rotation of structural elements. During the non-coaxial strain, strain fringes were formed as a consequence of the high circulation of fluids in low temperature and high pressure conditions. Superimposed strain fringes indicating right- and left-lateral senses of movement were recognized. At least three generations of fringes were recognized, implying three stages of non-coaxial stretching. Each generation has about 15 increments which show irregular strain gradient and intensity over the different increments. Eastwards, the strain increments became mature and westwards, the finite strain increases. The strongest finite strain was found in a narrow belt delimiting the basement rocks on the west and underlying the Phanerozoic sediments. Chocolate-tablet structure was recorded and indicates later multidirectional tension. Not all Nubia Sandstone exposures are overlying the basement rocks and some are separated by NW–SE normal faults. Major NW–SE normal faults are cutting basement rocks of different ages. © Saudi Society for Geosciences 2009

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