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Search Results: 1 - 10 of 4484 matches for " Ibrahim Gaafar "
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Geophysical Mapping, Geochemical Evidence and Mineralogy for Nuweibi Rare Metal Albite Granite, Eastern Desert, Egypt  [PDF]
Ibrahim Gaafar
Open Journal of Geology (OJG) , 2014, DOI: 10.4236/ojg.2014.44010

The present study aims to shed light on the rare metals of Nuweibiareaalbite granite in the Eastern Desert through the chemical analyses of the two types of fine-grained albite granite (FAG) and medium-grained albite granite (MAG) in addition to mineralogical studies as well as ground spectrometric survey and aeromagnetic mapping. On the basis of ground spectrometric measurements K, eUand eTh distribution maps were obtained. The concentration of K, U and Th content shows maxima (4.5%, 13 ppm and 27 ppm on average, respectively) in the FAG, and (4.5%, 10 ppm and 35 ppm on average) in the MAG. The eU/eTh ratio significantly increases in FAG with higher magma differentiation than MAG reaching 0.63. This paper uses magnetic geophysical methods to investigate geometry and sense of motion across the Nuweibi area. The interpreted structures from the magnetic maps are characterized by two main intersecting sets of NW-SE and NE-SW trending faults in addition to other three minor faults that trend in N-S, NNW-SSE and ENE-WSW directions. The NW-SE trending faults represent the recent sets in the study area where they are dissected and displaced by the other old faults. The Werner depth map shows the interface depths of the granite and basement rocks that extend to great depths ranging from 10 to 380 m. FAG is extended underneath most of the surrounding schist rocks because of their attributed low magnetic intensity that confirmed also with drilling. Microscope and Microprobe analyses indicated that the most important radioactive minerals include uranothorite, thorite, zircon, and monazite. Columbite group minerals represent the most common Nb-Ta host in Nuweibi-albite granites that contain significant levels of Ta (up to 65.4 wt. % Ta2O5) and Nb (up to 60 wt. % Nb2O5), with Ta/(Ta+Nb) ratio ranging from 0.17 to 0.84. Columbite group minerals are represented mostly by

Mineral Chemistry of Two-Mica Granite Rare Metals: Impact of Geophysics on the Distribution of Uranium Mineralization at El Sela Shear Zone, Egypt  [PDF]
Ibrahim Gaafar, Michel Cuney, Ahmed Abdel Gawad
Open Journal of Geology (OJG) , 2014, DOI: 10.4236/ojg.2014.44011

The present work aims at identifying Nb-Ta-, Zr-Hf-, REE-, Th-U-bearing two-mica granite from geological, geophysical cross-sections and mineral chemistry studies from three boreholes at G. El Sela shear zone. Microscopically, the three boreholes are composed mainly of two-mica granite. They are composed of K-feldspar, plagioclase, quartz, biotite and muscovite. Accessories are pyrite, zircon, fluorite, rutile, monazite with Th-U-mineralization identified by scanning electron microscope (SEM) and electron probe-microanalyses (EPMA). Chlorite, muscovite, sericite, kaolinite are secondary minerals. Geochemically, two-mica granite boreholes are A-type granites and peraluminous characteristics. They are enriched in large ion lithophile elements (LILE; Ba, Rb and Sr), high field strength elements (Y, Zr and Nb), and LREE but depleted in HREE with negative Eu anomaly. U-enrichment associated with chloritization, muscovitization, albitization, sericitization, kaolinization and argillization results from convective hydrothermal circulation of fluids through brittle structures along the ENE-WSW main shear zone. The ratios Nb/Ta (7.7 - 17.7) and Zr/Hf (16.9 - 26.4) are relatively enriched in the lighter isovalents Ta and Hf. The accessory minerals observed in the two-mica granites are represented by metallic sulfides (pyrite, arsenopyrite, chalcopyrite, galena and sphalerite), Nb-rutile, Hf-zircon, fluorite, monazite, columbite, betafite, thorite, phosphothorite, uranothorite, brannerite, uraninite, coffinite and pitchblende at G. El Sela shear zone. Uraninite with a low Th content indicates a hydrothermal origin of U-mineralization, Thorite, uranothorite, monazite and zircon is the main uranium bearing minerals of magmatic origin within the enclosing granite. The primary U-mineralization has been observed in two boreholes. In order to illustrate the geophysical signature of El Sela U-mineralization, the radiometric, magnetic, and VLF-EM data as well as radon concentration are included. The magnetic, electrical conductivity and radiometric profiles were produced from detailed ground surveys. The shear zone is characterized by relatively weak levels for both K and eTh, but very high eU anomalies (<3500 ppm), Therefore, the Sela shear zone acts as a good trap for U-mineralization. The Sela Shear zone coincides with positive conductivity anomalies, which are the most prominent features on the respective profiles. The magnetic field over the

Evaluation of wheat ear insects in large scale field in central Germany  [PDF]
Nawal Gaafar, Christa Volkmar
Agricultural Sciences (AS) , 2010, DOI: 10.4236/as.2010.12010
Abstract: Wheat ear insects in large scale winter wheat field in Salzmünde (SaxsonyAnhalt) central Germany were evaluated. The present study aimed at studying the abundance of wheat blossom midges WBM, Sitodoplosis mosellana (Géhin), Contarinia tritici (Kirby) and thrips, Li mothrips cerealium (Haliday) and Haplothrips tritici (Kurdjumov). Infestation in winter wheat during the growing seasons 2007, 2008 and 2009 was evaluated. Three methods were used to determine population densities and damage of wheat midges and thrips; pheromone traps, inspection of ear insects and water traps. A strong correlation between midge’s catches and weather conditions was obtained in field ob servations. A positive correlation between phe romone catches and ear infestation levels was recorded; it was higher in 2008 than in 2009. On the other hand, in 2007 there was no synchro nization; S. mosellana hibernated emerged too late to coincide with the susceptible wheat growth stages. The chemical treatment applied at 2008 for highly infestation; there were sig nificant differences in thrips and midge num bers between treated and untreated. Thrips and midge numbers were lower in the treated than in control. The high midge populations in water traps were recorded at growth stages 7779 and 83 and the low populations were recorded at GS 75 and 7577. This gives a reliable base for de cision making to midges control.
An Energy Aware WSN Geographic Routing Protocol
Adel Gaafar A.Elrahim,Hussein A.Elsayed,Salwa El Ramly,Magdy M. Ibrahim
Universal Journal of Computer Science and Engineering Technology , 2010,
Abstract: Wireless Sensor Networks (WSNs) consist of small nodes with sensing, computation, and wireless communications capabilities. Many routing, power management, and data dissemination protocols have been specially designed for WSNs. The focus has been given to the routing protocols which might differ depending on the application and network architecture. In this paper, we propose an energy efficient data forwarding protocol called Energy Aware Geographic Routing Protocol (EAGRP) for wireless sensor networks to extend the life time of the network. In EAGRP, both position information and energy are available at nodes used to route packets from sources to destination. This will prolong the lifetime of the sensor nodes; hence the network life time and thus get higher packet delivery ratio and minimal compromise of energy efficiency. The proposed protocol is an efficient and energy conservative routing technique for multi-hop wireless sensor networks. The routing design of EAGRP is based on two parameters: location and energy levels of nodes. Each node knows the location and energy level of its neighbors. The performance measures have been analyzed with variable number of nodes. Our simulation results indicate that the proposed algorithm gives better performance in terms of higher packet delivery ratio, delay, and energy consumption.
Efficacy of Allium sativum (garlic) against experimental cryptosporidiosis
MR Gaafar
Alexandria Journal of Medicine , 2012,
Abstract: Background: Due to increasing problems of inadequate and unreliable medical treatments for Cryptosporidium enteritis, alternative therapies are being sought. Objective: The current study was designed to evaluate the prophylactic and therapeutic efficacy of Allium sativum (garlic) against Cryptosporidium infection in experimentally infected immunocompetent and immunosuppressed mice. Methods: Forty eight male Swiss albino mice were divided equally into control and experimental groups. Each group was further subdivided into four equal subgroups; two immunosuppressed and two immunocompetent. Cryptosporidial oocysts were isolated from human stools, and were used to infect the mice. The experimental subgroups received garlic orally two days before infection or one day following infection, and continued daily till the end of the study. Two weeks following garlic administration, mice stools were examined for counting the cryptosporidial oocysts, then the animals were sacrificed; their small intestines were processed and were examined for detection of the pathological lesions and for counting of the parasites. Also, myeloperoxidase (MPO) activity was measured in jejunal sections. Results: The results showed that the infected immunosuppressed subgroups of mice; showed a statistically significant increase in the number of cryptosporidial oocysts in stool and ileal sections, as well as an increase in the MPO activity when compared to the corresponding immunocompetent subgroups. Garlic successfully eradicated the Cryptosporidium oocysts from stool and intestinal sections of the infected immunocompetent subgroup of mice receiving garlic two days before the infection. Besides, the oocysts were significantly reduced in all other infected experimental subgroups in comparison to the corresponding infected control subgroups. The intestinal sections of all subgroups received garlic before or after the infection, revealed a more or less normal architecture. Reduction in the level of MPO activity was also detected in all experimental subgroups. Conclusion: Our findings suggest that garlic is a convenient prophylactic and a promising therapeutic agent for cryptosporidial infection.
Molecular marker analysis of heading date Hd1 locus in Egyptian rice varieties
RM Gaafar
African Journal of Biotechnology , 2010,
Abstract: Nine molecular markers derived from the heading date QTL Hd1 DNA sequence for cultivated rice were used to study the heading date allelic diversity of the cultivated Egyptian rice varieties. The results showed that among the nine simple sequence repeats (SSR) and sequence tagged-sites (STS) markers used, one SSR marker, Hd1AGC, amplified three polymerase chain reaction (PCR) fragments (alleles) of various sizes (441, 490, and 620 bp) in all rice varieties, while the rest of the markers amplified only one non-polymorphic PCR fragment. The study also exhibited that Hd1AGC amplified a unique PCR fragment (620 bp) linked to early heading date in Giza 177 and Sakha 103.
Uniformly stable solution of a non-autonomous delayed system with Caputo fractional derivative
F. M. Gaafar
International Journal of Mathematical Analysis , 2012,
Effect of microwave irradiation on parametric resonance in intrinsic Josephson junctions
Mahmoud Gaafar,Yury Shukrinov
Physics , 2012, DOI: 10.1016/j.physc.2012.11.011
Abstract: The effect of microwave irradiation on the phase dynamics of intrinsic Josephson junctions in high temperature superconductors is investigated. We demonstrate the influence of microwave's amplitude variation on the current-voltage characteristics and on the time dependence (temporal oscillations) of the electric charge in the superconducting layers. A remarkable changing of the longitudinal plasma wavelength at parametric resonance is shown. We demonstrate an effect of the microwave radiation on the width of the parametric resonance region.
Spiral Tuning Stub CPW-Fed UWB Slot Offset, Edge Cleft and Edge Slotted Antennas  [PDF]
A. A Jamali, A Gaafar, A. A. Abd Elaziz
Wireless Engineering and Technology (WET) , 2011, DOI: 10.4236/wet.2011.23021
Abstract: After the release of the unlicensed Ultra Wideband (UWB) spectrum 3.1 GHz to 10.6 GHz for the commercial purposes by the Federal Communications Commission (FCC), industries and academia pay much attention due to its properties of excellent immunity to multi-path interference, high secured data rate, low power consumption, and simple configuration. The feasible UWB antenna design face some challenges including the ultra wide impedance matching, omni directional radiation pattern, constant gain, high radiation efficiency, low profile, compact antenna size and easy manufacturing. since the CPW fed planar slot antennas have the advantages of wide bandwidth, simple structure, less radiation loss, low cost and easy integration of monolithic microwave integrated circuits (MMIC). In general two parameters affect planar slot antennas impedance bandwidth, the slot width and feed structure. CPW-Fed Slot Antenna with Triangular Tuning Stub, the slot shape could be bow-tie slot, wide rectangular slot, circular slot and hexagonal slot. The impedance tuning can also be performed by using coupling techniques like inductively and capacitively coupled slots, dielectric resonator coupling and other techniques such as using photonic band gap (PGB). Using these techniques, large impedance bandwidth could be obtained but they are quite complicated. Planar slot antennas have two parameters that affect impedance bandwidth, the slot width and the feed structure. The optimum feed structure gives the good impedance matching and the wider slot gives more bandwidth. The proposed antenna in this paper is designed with a compact rectangular slot and a rectangular spiral feeding structure at the interior portion of the feed. The antenna is cleft and slotted at the edge and the effects is studied. The antenna only one of its kinds in structure, small in size and simple design due to less number of design parameters compared with the existing ultra wideband antennas in the literature. The bandwidth, gain, directivity and other antenna parameters are at acceptable level. IE3D method of moments based simulation software is used for this analysis. The proposed antenna design and its experimental result details is presented and discussed.
Genotypic Variations in Phenolic, Flavonoids and Their Antioxidant Activities in Maize Plants Treated with Zn (II) HEDTA Grown in Salinized Media  [PDF]
Zeinab A. Salama, Alaa A. Gaafar, Mohamed M. El Fouly
Agricultural Sciences (AS) , 2015, DOI: 10.4236/as.2015.63039

Zinc (Zn (II) HEDTA) was used to determine their effect on salt-induced damages in maize plants. The aim of this study was to investigate the antioxidant capacity and the levels of enhanced total phenolic (TPC), total flavonoid (TFC) contents and their antioxidant activity in leaves of two maize cultivars Single cross 10 (SC10) and Single cross 162 (SC162) grown in two levels of salinity 0.00 and 100 mmol in response to 20 μmol Zn (II) HEDTA foliar spray treatments. Significant differences (P ≤ 0.05) in amounts of TPC ranged from (2.55 to 4.62 mg/gdw as Gallic) in Single cross 10 (SC10) and from (2.53 to 4.38 mg/gdw as Gallic) in Single cross 162 (SC162), TFC (ranged 1.53 to 2.41 mg/gdw as qurestien) in Single cross 10 (SC10) and from (1.28 to 2.41 mg/gdw as qurestien) in Single cross 162 (SC162) among all treated plants were observed. The levels of their compounds increase related to foliar spraying of Zn (II) HEDTA. A significant positive correlation between TPC, TFC and DPPH scavenging activity and iron chelating activity was observed which shows that phenolic compounds were involved in the mechanism of salt tolerance of the two cultivars by showing enhanced antioxidant activity which resulted in reduced membrane damage and hence improved growth. According to the results obtained, the adverse effects of salt stress on maize plants can partly be alleviated with application of Zn (II)-HEDTA chelates. It is concluded that the application of Zn (II) HEDTA to maize plants grown in salt conditions leads to the increase of antioxidant compounds and maize tolerance.

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