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Search Results: 1 - 10 of 13634 matches for " Hesham Azmi El Meleegi "
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Dielectric and Magnetic Properties of Nano-Structure BiFeO3 Doped with Different Concentrations of Co Ions Prepared by Sol-Gel Method  [PDF]
Inas Kamal Batttisha, Ibrahim Sayed Ahmed Farag, Mostafa Kamal, Mohamed Ali Ahmed, Emad Girgis, Fawzi El Desouki, Hesham Azmi El Meleegi, Fawzi El Desouki
New Journal of Glass and Ceramics (NJGC) , 2015, DOI: 10.4236/njgc.2015.53008
Abstract: BiFe1-xCoxO3 (x = 0, 0.03, 0.05 and 0.1) symbolic as (BFO, BF3CO, BF5CO and BF10CO) in powder form has been prepared by sol-gel technique using ethylenediamine tetraacetic acid (EDTA) as a chelating agent. X-ray diffraction (XRD) and FTIR analysis showed rhombohedra distorted BiFeO3 structure with compressive lattice distortion induced by the Co substitution at Fe sites. The transmission electron microscope (TEM) shows irregular particles. The additive of cobalt oxide has led to grains refining giving the following crystallite sizes of 18 nm for BF5Co. The scanning electron microscope (SEM) study reveals that the samples morphology shows relatively uniform grain size distribution. The dielectric properties of BiFeO3 nano-particles in the frequency range of 1 up to 5 MHz at RT revealed that the A.C. conductivity of the prepared samples reaches its maximum value in BF5CO. By decreasing BiFeO3 particle size as a result of doping with different Co ion concentrations, an enhancement in magnetization and a simultaneous suppression in current leakage occurred. The remnant magnetization Mr of BiFe1-xCoxO3 (x = 0, 0.03, 0.05, 0.1) ceramics significantly enhanced, which provides potential applications in information storage.
Structural, Magnetic and Dielectric Properties of Fe-Co Co-Doped Ba0.9Sr0.1TiO3 Prepared by Sol Gel Technique  [PDF]
Inas Kamal Batttisha, Ibrahim Sayed Ahmed Farag, Mostafa Kamal, Mohamed Ali Ahmed, Emad Girgis, Hesham Azmi El Meleegi, Fawzi Gooda El Desouky
New Journal of Glass and Ceramics (NJGC) , 2014, DOI: 10.4236/njgc.2014.42003
Abstract: The structural, dielectric and magnetic properties of pure and Fe-Co co-doped Ba0.9Sr0.1TiO3, (Ba(1-x)SrxTiO3, where (x = 0.10) and (Ba0.9Sr0.1Ti(1-x-y)FexCoyO3), where (x = 0.1, y = 0) and (x = 0 and y
Information Culture in The 21 th Century
Hesham Azmi
Cybrarians Journal , 2006,
Abstract:
Teaching information literacy skills: a case study of the QU-core program in Qatar University
Hesham Azmi
ITALICS , 2006,
Abstract: Purpose: The study examines students’ assessment of a general requirement course entitled “Basics of Information Technology”.Methodology: A written survey was distributed to 80 students in 3 different classes. 61 surveys (76% of the total) were returned within the study period.Results: Respondents stated that knowledge and skills acquired are essential to pursue their studies in the university and beyond. Using search engines and searching databases were identified as the most important skills acquired. Discrepancy in course description, delivery methods and assessment tools were seen as the main obstacles. Practical implications: The study provides ideas, concepts and guidelines for introducing a new information skills course within Qatar University Core Curriculum.
Development of Solar Ponds Optimization Model: Arab Potash Solar System—A Case Study  [PDF]
Hesham El-Badry
Natural Resources (NR) , 2013, DOI: 10.4236/nr.2013.41010
Abstract:

A steady state optimization model used to define the optimum salt to carnallite ponds area ratio in a solar pond system was developed. The model is based on material balance analysis using a cascade of complete-mix reactors model (cascade of CFSTR, continuous-flow stirred-tank reactor) prepared for the solar pond system. The basic material balance model shall use the basic phase chemistry relations and physical parameters of the solar pond system under optimization. The Arab Potash solar pond system data was used to examine the developed model where the Arab potash solar system was used as a Case Study. In the course of the model development, calibration and validation of the model is performed. Using this steady state model the optimum salt pond to carnallite pond area ratio is deduced. This optimum ratio is defined as the optimum area ratio that maximizes the carnallite production per the total pond system area. This term, which could be expressed as tons per km2, presents the best pond system efficiency. The results show that a 1.88 ratio of salt to carnallite ponds area is the optimum ratio.

Electrowinning of Copper Using Rotating Cylinder Electrode Utilizing Lead Anode  [PDF]
Hesham Soliman, Ahmed Abd El-Moneim
Engineering (ENG) , 2011, DOI: 10.4236/eng.2011.34039
Abstract: The effect of lead anode, rotating cylinder electrode (RCE), amount of 1,2-dihydroxypropane (12-DHP), temperature and rotation on the electrowinning of copper from low concentration acidified copper sulphate solution has been investigated. Copper powder was electrodeposited onto RCE that made of pure copper. From cyclic voltammetry experiments, an empirical parameter called the departure percent, S, was obtained which may represent the stability of the organic additive in the given medium and under the experimental conditions. The inhibition percentage, P, was 0.00 - 89.91% depending on the experimental variables. P was affected by temperature and mole fraction of 12-DHP, while rotation did not show any influence on it. Values of activation energy of electrodeposition process, Ea, were found to be less than 28 kJ mol-1 indicating diffusion controlled process. The overall mass transfer correlations under the present conditions have been computed using the dimensional analysis method. The data were valid for 90 < Sh < 1098, 737 < Sc < 59284 and 271 < Re < 7046 and the results agreed with the previous studies of mass transfer to rotating cylinders in turbulent flow regimes. The effect of time, content of 12-DHP, temperature and the speed of rotation on the morphological changes of the electrodeposited copper powder as well as deposits composition and crystallite size have been studied. Various crystallite sizes ranged 7.1 nm - 250.6 nm were obtained and characterized by EDS and XRD. Different topographs proved that the rate of copper electrodeposition increased by increasing deposition time, temperature and the speed of rotation. Also, they proved that the deposition rate decreased by adding 12-DHP to the solution. Therefore, the results obtained by SEM supported those achieved by measuring the limiting current density and follow the normal manner when organic solvents were added to the electrodeposition bath.
Mesoscale Numerical Study of Quasi-Stationary Convective System over Jeddah in November 2009  [PDF]
Mohammed Haggag, Hesham El-Badry
Atmospheric and Climate Sciences (ACS) , 2013, DOI: 10.4236/acs.2013.31010
Abstract:

25 November 2009 is an unforgettable day for the people in Jeddah, the second largest city in the Kingdom of Saudi Arabia (KSA). On that day, Jeddah turned into a disaster zone following a short heavy rainfall event that triggered flash floods leaving 122 fatalities and considerable losses. Numerical experiments using the Pennsylvania State University-National Center for Atmospheric research mesoscale meteorological model (MM5) have been performed to investigate the event. It was caused by a short quasi-stationary mesoscale convective system that developed over Jeddah and lasted for about 8 hours. Rainfall totals computed by the model exceeded 400 mmin some localities in the southern part of Jeddah city and to the north of Jeddah in Thuwal city. The limited available observed rainfall totals, atKingAbdulAzizInternationalAirportand wadiQaws rain gauges, and Jeddah’s weather radar observations corroborates the ability of the model to reproduce the spatial and temporal characteristics of the rainfall event. A synoptic environment characterized by warmRed Seasurface temperatures and high humidity in the low levels of the troposphere. A stationary anticyclone centered over the southeast of theArabian Peninsulaconcentrated the water vapour flow to a narrow passage over Jeddah. Simulation results suggested that the development of a mesolow by latent heat release, as well as cyclogenesis induced by Al Hejaz escarpments, could have played an important role in enhancing the event by providing low-level convergence and enhanced upslope winds, and upper level atmospheric instability.

Muscles Transfer around the Shoulder in Cases of Brachial Plexus Birth Palsy  [PDF]
Hesham El Sobkey
Open Journal of Modern Neurosurgery (OJMN) , 2019, DOI: 10.4236/ojmn.2019.93026
Abstract: Background:Disabling internal rotation contractures are frequently experienced in children with unresolved birth brachial plexus palsies. Multiple surgical options like muscle release, tendon transfer, or humeral osteotomy are available to treat such cases. Purpose:Evaluation of the outcome of subscapularis release and latissimus dorsi and teres major tendon transfer in the management of obstetric brachial palsies in Mansoura University neurosurgical department. Study type: Retrospective observational study. Patients and Methods: Twenty-five cases who underwent subscapularis release and latissimus dorsi and teres major transfer were included in the study. All patients were subjected to complete history taking, through clinical examination. The degree of shoulder movement and disability was assessed via Modified Gilbert shoulder evaluation scale. Results: The least follow up period for our patients was 9 months. There was a clear improvement of shoulder function evaluated using Modified Gilbert shoulder evaluation scale as there were 73% of postoperative group between GIV and GV while about 84% of preoperative group were between GII and GIII. Conclusion: Tendon transfer is a valid easy procedure for correction of shoulder deformities in patients with obstetrical brachial plexus palsy. It is considered a very good option for patients who missed the chance of microsurgical repair or patients with poor shoulder recovery after surgery. Although some authors reported deterioration of shoulder function with log time follow up after tendon transfer, it is still better than those who were not operated.
Use of Nitric Oxide Donor Isosorbide Mononitrate for Cervical Ripening at 41 Weeks’ Gestation  [PDF]
Mohamed Elmahdy, Hesham Galal, Amany El Marsafawi, Nahla Amin
Open Journal of Obstetrics and Gynecology (OJOG) , 2016, DOI: 10.4236/ojog.2016.68060
Abstract: Background: The ideal agent for cervical ripening would induce adequate cervical ripening with minimal adverse effects to the mother and the fetus; the most favorable method for cervical ripening is not fully agreed till now; however, vaginal administration of isosorbide mononitrate (IMN) is considered a low-risk method of labor induction for post term. Our study was designed to assess the effect of IMN on cervical ripening and labor induction among 41 weeks pregnant women. Objectives: To assess the efficacy of the nitric oxide donor isosorbide mononitrate on cervical ripening at 41 weeks gestation. Materials and Methods: This study was conducted on 100 pregnant women recruited from the outpatient clinic fulfilling the inclusion criteria. Cases were divided into 2 groups. In first group 40 mg isosorbide mononitrate (IMN) tablet was applied vaginally in posterior fornix, and in second group placebo was applied vaginally in posterior fornix. Following up the cervical status after 24 hours of administration, the patient were asked about new symptoms especially headache, palpitation, dizziness or abdominal pain and the mode of delivery was assessed. Results: There was a significant improvement in the bishop score in the first group rather than the placebo group. No significant difference between the two groups was as regards the mode of delivery. Conclusion: IMN may be used for cervical preparation only before induction of labor in post term cases.
New mechanized system for circle spraying of oil palms seedling emergence
El Pebrian, Darius;Yahya, Azmi;
Scientia Agricola , 2012, DOI: 10.1590/S0103-90162012000200002
Abstract: a new machine system has been designed, developed and evaluated for extensive circle spraying of oil palms (elaeis guineensis jacq.) in an effort to overcome the inefficient spraying problem with the conventional spraying system. the machine system consists of a four-wheeled drive 4wd prime mover with front mounted machine attachments for the circle spraying operation. the configuration of the circle spraying attachment consists of a hexagonal curved spray boom, lifting arm, opening-tilting mechanism unit, storage tank, spray pump, solid cone nozzles, and associate hydraulic system. field performance tests on the machine system showed an average effective field capacity of 7.89 ha per man per day and when compared to the earlier reported effective field capacity of the walking spray-operated equipment using serena lt16 knapsack sprayer; a difference of 1.97 time for circle spraying of mature palms grove. reduction in the human energy expenditure of 101.28 kj man-1 h-1 or 10.68 % but an increase in the spraying cost of 1.53 usd ha-1 or 24.9 % were obtained with the machine system against the walking spraying-operated equipment using serena lt16 knapsack sprayer. justification for machine system to be cost effective could be satisfied if the present effective field capacity is increased to 1.263 time with good skilled operator or if the current r&d cost is reduced to 0.41 time. this is because the improved field capacity of new machine system could not rationalize its current r&d cost. admittedly, the machine system has great potential to overcome the limitations with the current employed machine/equipment in the circle spraying operation of oil palms in the plantation.
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