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Damietta, Egypt

Hereher M.E.,Damietta University
Environmental Earth Sciences | Year: 2014

The High Dam in Aswan was designed so that if the water level behind the dam approaches 178 m above the sea level, surplus water should be diverted naturally toward the Toshka depression in the Western Desert of Egypt. The objective of this study was designed to map the spatial extent of temporal changes that occurred as a result of the formation of Toshka artificial lakes west of the Nile Valley from 2000 to 2013 using the Moderate Resolution Imaging Spectroradiometer (MODIS). A group of spectral transforms have been examined to extract the surface area of water in the lakes as revealed in 14 MODIS images on the basis of one image per year. The Land Surface Water Index, the Normalized Difference Vegetation Index (NDVI), and the new Normalized Difference Lake Index (NDLI) were operated. Results showed that the NDLI was the best to eliminate spectral interferences from surrounding non-water objects. The lakes, which approached their maximum surface area in 2002 have experienced considerable diminishing and are expected to eventually disappear due to evaporation. Salinization and sand encroachment were observed in satellite data at areas, which were previously inundated by water. MODIS images have proved that they could afford an efficient and sustainable source of remotely sensed information for monitoring water bodies in hyper-arid deserts. © 2014 Springer-Verlag Berlin Heidelberg. Source


Hereher M.E.,Damietta University
Egyptian Journal of Remote Sensing and Space Science | Year: 2013

The emergence of satellite images with moderate spatial resolution and wide geographic coverage helped in the estimation of Egypt's entire agricultural land in 2003 and 2012. The country which is situated entirely in the arid region exclusively relies on irrigated agriculture. The enhanced vegetation index (EVI) was the algorithm operated to estimate the vegetated area of the country, which was estimated at 3.3% and 3.7% in 2003 and 2012, respectively. Time series analysis of satellite data revealed the vigor pattern of cultivated lands. © 2012 National Authority for Remote Sensing and Space Sciences. Production and hosting by Elsevier B.V. All rights reserved. 18. Source


Wahba H.H.,Damietta University
Optical Fiber Technology | Year: 2014

In this paper, the refractive indices distributions on the two birefringent axes of polarization maintaining (PM) PANDA type optical fiber are reconstructed. The local refraction of the incident rays crossing the PM optical fiber is considered. Off-axis digital holographic interferometric phase shifting arrangement is employed in this investigation. The recorded mutual phase shifted holograms, starts with 0° with steps of π/4, are combined and numerically reconstructed in the image plane to obtain the optical interference phase map. Consequently, the optical phase differences due to the PM optical fiber are extracted after unwrapping and background subtraction of the enhanced optical interference phase map. The birefringence and the beat length in the two directions, fast and slow axes of PM optical fiber, of polarizations in the core region are calculated. This holographic technique and the advanced analysis of the phase shifting permit the calculation of the 3D refractive index distributions for PM PANDA optical fiber. © 2014 Elsevier Inc. All rights reserved. Source


Moawed E.A.,Damietta University | El-Shahat M.F.,Ain Shams University
Analytica Chimica Acta | Year: 2013

In this work, a new type of sorbent (low density polyhydroxy polyurethane Foam, LPPF) was synthesis by using water hydrolysis of polyurethanediazonium chloride salt. LPPF was characterized using different tools e.g. elemental analysis, UV-vis and IR spectra, TGA, SEM, density and pHZPC. It was tested for separation, preconcentration and determination of gold in environmental samples using batch and dynamic techniques. The sorption experimental data was fitted by the pseudo-first kinetic mathematical equation (R2=0.991). The sorption rate of the Au (III) ions is very fast, the half-life (t1/2)≈34s. The equilibrium process is well described by the Freundlich isotherm model, the R2 value is 0.967, which attributed to the heterogeneous surface structure of the LPPF. The breakthrough capacity of LPPF and the recovery of gold ions were 0.36mmolg-1 (70.5mgg-1) and 99-100%, respectively. The lower detection limit of gold by using spectrophotometric method is 3.3ngL-1 with preconcentration factors≈450 (RSD~1.66%, n=4). The values of δG and δH for the sorption of gold onto LPPF were -12.5 and -103.5kJmol-1, respectively, which indicate that the sorption of Au (III) onto LPPF is spontaneous and exothermic reaction. The obtained results indicate that the ion chelation and ion association might be the most probable mechanism of gold sorption onto LPPF. The study shows LPPF has the potential of application as an efficient sorbent for the extraction and determination of gold in water, gold alloys pharmaceutical and granite samples. © 2013 The Authors. Source


The reductive perturbation technique is employed to investigate the propagation properties of nonlinear dust acoustic (DA) waves in a four-component inhomogeneous dusty plasma (4CIDP). The 4CIDP consists of both positive- and negative-charge dust grains, characterized by different mass, temperature, and density, in addition to a background of Maxwellian electrons and ions. The inhomogeneity caused by nonuniform equilibrium values of particle densities, fluid velocities, and electrostatic potential leads to a significant modification to the nature of nonlinear DA solitary waves. It is found that this model reveals two DA wave velocities, one slow, λs, and the other is fast, λf. The nonlinear wave evolution is governed by a modified Kortweg-de Vries equation, whose coefficients are space dependent. Both the two soliton types; compressive and rarefactive are allowed corresponding to λs. However, only compressive soliton is created corresponding to λf. The numerical investigations illustrate the dependence of the soliton amplitude, width, and velocity on the plasma inhomogeneities in each case. The relevance of these theoretical results with 4CIDPs observed in a multi-component plasma configurations in the polar mesosphere is discussed. © 2013 AIP Publishing LLC. Source

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