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  • Author or Editor: A. Saleh x
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Abstract  

N,N,N′,N′-tetraoctyldiglycolamide (TODGA) was synthesized and characterized with elemental analysis, infrared spectrometry and nuclear magnetic resonance spectrometry. The synthesized TODGA was applied for the extraction and separation of Zr(IV) and Hf(IV) from nitric acid solutions. The performed studies include the effects of TODGA, nitric acid, nitrate ion, hydrogen ion, and metal ion concentrations as well as time and temperature. TODGA shows effective extraction of Zr(IV) and Hf(IV) from HNO3 ≥ 3 M. However, the maximum separation factor (D Zr/D Hf) obtained using TODGA is 2.8.

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The impact of the combined stress factors of heavy metals (cadmium and nickel) and UV A+B radiation in Pisum sativum was investigated. Seeds were grown in sandy loam for 30 days, and then randomly divided into equal two groups. The first group was exposed for 5 hours/day to supplemental 6.4 KJ m −2 d −1 dose UV A+B radiation beside white light (1,100 Lux), while the second one was exposed to white light only giving light intensity (1,100 Lux). Plants from each group were irrigated with nutrient solution having 0.0, 5, 10 and 20 μmol Cd or Ni for two weeks and then harvested. The results showed that, Cd or Ni treatments induced significant decreased the length, fresh weight, dry weight and density of both root and shoot. UV A+B resulted in synergistic inhibitory effects of all measured growth parameters. Total chlorophyll, carotenoids, total carbohydrates and proteins showed a similar pattern to that of growth parameters. The amount of UV-screening pigments was highest under supplement of UV A+B radiation, while the combination of Cd or Ni and UV A+B caused further decrease. Thus, it could be shown that the combined treatment of UV A+B and Cd or Ni was antagonistic on UV-screening pigments. The combined sterss of UV A+B radiation an Cd or Ni also resulted in a reduction of peroxidase and catalase activity, while H 2 O 2 level and anthocyanin content were increased in Pisum sativum plant. The data showed that in some measured parameters there was a UV A+B and Cd or Ni synergistic effect, while with other parameters an antagonistic action was observed.

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Magnetotelluric method (MT) offers opportunity to detect crustal fluids along faults due to their high conductivity anomaly. Supposing that fluids deposited minerals in the conductive fractures (faults, dykes) decreasing the resistivity, the high seismicity in the area can be explained by the presence of these fluids. MT measurements were carried out in the period range 0.001–420 s crossing the Kalabsha fault (Aswan, Egypt) and Remiremont fault (Southern Vosges, France). In these work we detect geoelectrical resistivity anomalies of the Earth’s crust and link them to local seismic activity. Seismic events having magnitude (M<5) are found along fault zones in Kalabsha and Remiremont. The goals of our measurements are various. We would like to determine the precise location of the active faults, to study the connection of the Remiremont and Kalabsha seismicity to the MT resistivity structures, and to support the idea of the influence of the fluid-bearing conducting faults in the Remiremont and Kalabsha areas to the earthquake. These applications afford the unusual opportunity to study the percolation of water into the faults system and its effect on the seismicity, to reveal geological structures and the stress field covered by thin Quaternary formations. Data are analysed by 2D simultaneous inversion of both polarizations. The resulting models are compared with the local seismicity map. Our MT model reveals the conductive signature of the fault, as well as geological and tectonic stresses prevailing in active regions.

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Three-dimensional gravity modeling has been performed for the Eastern Mediterranean including the northeastern Egyptian off-shore area. The gravity models and seismic profiles indicate that a transition from two layer continental crust to a simple layer oceanic crust takes a place along the Levantine margin. The transition along three profiles is located beyond the north African continental margin and it is quite gradual. The crust under the Levantine basin is typically oceanic and slightly thin with 13 km thickness, however it is typical continental under the Egyptian off-shore and having 30 km thickness. The obtained results reflect a large sedimentary sequence of 14 km under the Levantine basin. Since the sediments recovered by the Oceanic Drilling Program Leg160 in the eastern Mediterranean ranged from Pleistocene to Cretaceous, this reflects fairly high sedimentation rate. Distribution of recent earthquake foci indicates that almost all earthquakes occurred along the western and central segments of the Cyprean arc while they completely disappear along the eastern segment. This means that collision between Cyprus and the Eratosthenes seamount is marked by seismic activity and clearly affects the shape of the Cyprean arc. This collision represents a transition zone between active compression and probable subduction in the western segment and diffuse transtension through the eastern part of the arc. Incipient collision between Cyprus and Eratosthenes seamount probably began in Pleistocene time.

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Abstract  

In XRF spectra, secondary fluorescence by X-rays produced in the target itself is one of the main reasons for incorrect analytical results. In our investigation we present a new approach for the determination of the X-ray enhancement using samples of known composition, which are, for certain elements, subject to enhancement effects.

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Abstract  

The quantitative interpretation of X-ray fluorescence /XRF/ data is often difficult because of matrix effects. The intensity of fluorescence measurement for a given element is not only dependent on the concentration of the element, but also on the mass absorption coefficients of the sample for both excitation and fluorescent radiation. In this paper, a new approach for the determination of absorption and transmission correction factors is described.

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Abu-Dabbab area is characterized by high seismicity and complex tectonic setting, for these facts, a local geodetic network consisting of eleven geodetic benchmarks has been established. The crustal deformation data in this area are collected using the GPS techniques. Five campaigns of GPS measurements have been collected, processed and adjusted to get the more accurate positions of the GPS stations. The horizontal velocity vectors, the dilatational, the maximum shear strains and the principal strain rates were estimated. The magnitude of the movements is distributed inhomogeneous over the area and it varies in average between 3 and 6 mm/yr. The results of the deformation analyses indicate a significant contraction and extension across the southern central part of the study area which is characterized by high seismic activity represented by the clustering shape of the microearthquakes that trending NE-SW direction. The north and north-eastern parts are characterized by small strain rates. This study is an attempt to provide valuable information about the present state of the crustal deformation and its relationship to seismic activity and tectonic setting at Abu-Dabbab area.

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Abstract  

For the determination of cadmium in sea water, a neutron activation analysis method involving a preconcentration step has been developed. Preconcentration is achieved by co-precipitation of cadmium dibenzyldithiocarbamate with phenolphthalein. The precipitate is collected on 0.45 μm membrane filters and cadmium is determined by instrumental neutron activation analysis. A115mCd radio tracer was used to establish optimum conditions and to evaluate the chemical yield.

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Eight phytoseiid species were tested to evaluate their potential as predators of Tuta absoluta (Meyrick) eggs as an alternative/natural food source under laboratory conditions. Predatory phytoseiid mites were, namely: Typhlodromips swirskii (Athias-Henriot), Euseius scutalis (Athias-Henriot), Cydnoseius negevi (Swirski and Amitai), Neoseiulus barkeri (Hughes), Neoseiulus californicus (McGregor), Phytoseius finitimus Ribaga, Proprioseiopsis badri (Yousef and El-Borolossy) and Amblyseius largoensis (Muma).Immatures survival of tested phytoseiid species were low on eggs of T. absoluta and all failed to develop to adulthood.Adult females of C. negevi, A. largoensis and N. barkeri were able to feed and sustain oviposition on eggs of T. absoluta. A diet of insect eggs provided the shortest oviposition period and adult longevity of C. negevi, while A. largoensis showed the longest corresponding periods. The total and daily number of insect eggs consumed was significantly higher in N. barkeri and C. negevi than in A. largoensis. Similarly N. barkeri laid significantly higher number of eggs (47.39 eggs/female) than that deposited by C. negevi and A. largoensis (41.0 and 30.7 eggs / female). The sex ratio of the progeny was strongly female biased and ranged: (females/total=61.8−75.4%) when insect eggs were provided for C. negevi, N. barkeri and A. largoensis.Survival of adult females of T. swirskii, P. badri, N. californicus, E. scutalis and P. finitimus were low on T. absoluta eggs and all died within 2–4 days.

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