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.
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.
Hereher M.E.,Damietta University
Arabian Journal of Geosciences | Year: 2015
The present study provided an integrated scheme of utilizing digital elevation models (DEMs) along with five Landsat satellite images between 1973 and 2013 in order to delineate the extent and capacity of El-Rayan depression, Egypt, and to highlight temporal changes which occurred upon the two anthropogenic lakes formed from the discharge of agricultural drainage wastewater within the depression. The capacity of the valley as well as water volume was estimated from DEM data, and water surface area was estimated by applying mathematical indices compiled from spectral bands in satellite data. The modified normalized difference water index (MNDWI) was the algorithm operated in this study. Results showed that the area of the depression at the sea level approaches about 352 km2, and the depression can store as much water as 6.45 billion m3. Water body of the two lakes has experienced reduction by seepage, evaporation, and shrinking to about 86 km2 in July 2013. Most shrinking was encountered at the lower lake due to drifting sand and local cultivation. © 2014, Saudi Society for Geosciences.
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.
El-Taibany W.F.,Damietta University
Physics of Plasmas | Year: 2013
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.
Baka Z.A.M.,Damietta University
Archives of Phytopathology and Plant Protection | Year: 2014
This study was carried out to evaluate the antifungal potential of water and ethanol extracts from aerial parts of five wild medicinal plants collected from Sinai Peninsula, Egypt, and the extracts were tested in vitro and in vivo against Phytophthora infestans, the causal agent of late blight disease of tomato. The five wild medicinal plants used for the study were Asclepias sinaica, Farsetia aegyptia, Hypericum sinaicum, Phagnalon sinaicum and Salvia aegyptiaca. Ethanol extracts were more effective on the pathogen than water extracts at all concentrations used. Water and ethanol extracts of all plants tested reduced mycelial growth and inhibited spore germination of the pathogen with varying degrees. Water and ethanolic extracts also reduced the disease infection with pathogen comparing with control in detached leaves technique. In all experiments, extracts of A. sinaica and F. aegyptia were most effective on the pathogen than other plant extracts. In plot experiment, the water and ethanolic extracts of A. sinaica and F. aegyptia gave the most reduction of late blight disease severity comparing with control. Also, data indicated that after the application of plant extracts, there was an increase in fruit yield of tomato corresponding with the reduction of disease severity. Scanning electron microscopy revealed a negative alteration of pathogen hyphae treated with A. sinaica extract at 20%. This concentration of the same plant extract also reflected in dramatic changes in the cyto-morphology of pathogen hyphae as observed by transmission electron microscopy. These changes resulted in an increase in vacuolisation and lipid contents with consequent reduction of cytoplasm with alteration of cell wall and plasmalemma. The overall results suggested that the use of these Egyptian wild medicinal plant extracts was promising, effective and environment-friendly management measure against Phytophthora blight of tomato and thus, may be used in the production of organically grown vegetables. © 2014 © 2014 Taylor & Francis.
Mohamed Baka Z.A.,Damietta University
Journal of Plant Protection Research | Year: 2014
Grain samples of 14 Egyptian wheat cultivars were tested for seed-borne fungi. The deep freezing method was used. Five seed-borne fungi viz., Aspergillus flavus, A. niger, Curvularia lunata, Fusarium moniliforme and Penicillium chrysogenum were isolated from the wheat cultivars viz., Bani Suef 4, Bani Suef 5, Gemmiza 7, Gemmiza 9, Gemmiza 10, Giza 168, Misr 1, Misr 2, Sakha 93, Sakha 94, Shandaweel 1, Sids 1, Sids 2 and Sids 3. A. flavus, A. niger and F. moniliforme were the most prevalent fungal species. Their incidence ranged from 21.0-53.5%, 16.0-37.5%, and 12.0-31.0%, respectively. The antifungal potential of water extracts from aerial parts of five wild medicinal plants (Asclepias sinaica, Farsetia aegyptia, Hypericum sinaicum, Phagnalon sinaicum, and Salvia aegyptiaca) were collected from the Sinai Peninsula, Egypt. The antifungal potential of water extracts from the aerial parts of these five plants were tested in the laboratory against the dominant fungi isolated from the wheat cultivars. All the aqueous plant extracts significantly (p ≤ 0.05) reduced the incidence of the tested seed-borne fungi. But the extract of Asclepias sinaica exhibited the most antifungal activity on tested fungi at all concentrations used when compared with other plant extracts. Maximum infested grain germination was observed in Giza 168 and minimum in Bani Suef 5. Treating grains with plant extract of A. sinaica (10%) enhanced the percentage of grain germination of all cultivars in both laboratory and pot experiments. Maximum root and shoot length of seedlings was recorded in Bani Suef 4 during fungal infestation or treatment by plant extract. For one hour before sowing or storage, the aqueous extract of A. sinaica can be used to treat wheat grains, to reduce the fungal incidence. Aqueous extracts of the aerial parts of selected medicinal plants, particularly A. sinaica, are promising for protecting Egyptian wheat grain cultivars against major seed-borne fungi. The aqueous extracts are expected to improve crops. © by Zakaria Awad Mohamed Baka 2014.
Hereher M.E.,Damietta University
Journal of Coastal Research | Year: 2015
Hereher, M.E., 2015. Assessment of South Sinai coastal vulnerability to climate change. Coastal vulnerability assessment is important to help achieve the sustainable use of coastal resources and to incorporate coastal hazards into coastal planning and decision making for integrated management. This study applied the coastal vulnerability index (CVI) to delineate susceptibility of the South Sinai coastline to climate change. The following variables pertaining to inherent shoreline characteristics were used in the assessment of the CVI: coastal slope, coastal geomorphology, fauna/flora, and socioeconomic factors. GIS and remote sensing analysis were employed to extract intrinsic attributes of the coast in this study area. Results showed that about one half of the 635-km-long coastline is exposed to high and very high coastal vulnerability to climate change, and global warming could exacerbate biologic suffering in the region. The Gulf of Suez is likely to be more vulnerable than the Gulf of Aqaba. Most areas susceptible to climate change include gentle, unconsolidated, coral assemblages and inhabited coastal segments. Coastal zone managers should implement remediation plans for any anticipated ecosystem disruption episodes. © 2015 Coastel Education and Research, Inc.
Hereher M.E.,Damietta University
Geomatics, Natural Hazards and Risk | Year: 2015
The Egyptian Mediterranean coast was examined for the vulnerability to sea-level rise using the coastal vulnerability index (CVI), which was derived from the geologic and physical characteristics of the coast. This paper is the first to apply the CVI along the Egyptian coasts. The coast has different geomorphologic aspects ranging from steep-slope-rocky cliffs to gentle sloping deltaic sediments. Although the coast is under low tidal effect and low height waves, results showed that more than one-third of the 1000 km long coast is severely vulnerable to sea-level rise. Unfortunately, the area under high vulnerability to sea-level rise comprises the densely populated Nile Delta coast. National actions should be implemented to safeguard the entire coast at the threatened locations. © 2013, Taylor & Francis.
Ahmed E.M.,Damietta University
Current Applied Physics | Year: 2013
Density and current-field characteristics related to switching phenomenon in zinc-doped strontium iron vanadate glasses having the formula (70 - x)%V 2O 5-x%ZnO-10%SrO-20%FeO, have been investigated over a wide composition range [0 ≤ x ≤ 15] at different thicknesses and temperatures. The samples are found to show threshold switching behavior. The switching fields are found to increase with the increase of zinc content while they decrease when the temperature is increased. The activation energy for switching was found to increase with the increase of ZnO content. Finally, the switching results are discussed in terms of the electrothermal model depending on the samples thicknesses and power calculus. © 2012 Elsevier B.V. All rights reserved.