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Search Results: 1 - 10 of 8908 matches for " Mohamed Elmamy "
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Sizing Method of a Storage System for Determining the Performance of a Photovoltaic Pumping System over the Sun  [PDF]
Mohamed Elmamy Mohamed Mahmoud, Mr. Soukeyna, A. Yahfdhou, A. K. Mahmoud, I. Youm
Smart Grid and Renewable Energy (SGRE) , 2019, DOI: 10.4236/sgre.2019.102002
Abstract: The use of renewable energy is growing significantly in the world. In front of the growing demand for electric energy, essentially for the needs of remote, isolated and mountainous regions, photovoltaic systems, especially water pumping systems, are beginning to emerge in large applications. In this sense, the proposed study deals with the problem of the water level regulation in the photovoltaic pumping system. It is in this context that the interest in this paper is dictated by the need to use an existing energy source on the site. Still in this light, it is important to note that, often, the calculation of the size of the GPV that feeds the pumping system and the pump involves a certain degree of uncertainty, mainly due to two main reasons: the first is related to randomness of solar radiation which is often little known and the second is related to the difficulty to estimate the water needs. This is why, on the one hand, the realization of such a system has made it possible to show the possibility of determining the projected quantity for water storage. Similarly, it has shown that the prediction of this quantity of water can be calculated by a simple analytical method based on numerical computation. Thus, it was also shown for this pumping system, thanks to graphical analysis methods, developing autonomy, reliability and good performance. In this sense, this experience opens the door for a practical and economical solution to the problem of lack of water, especially in our regions. Measurements made on the studied system prove that the designed approach improves the efficiency. Finally, it is also expected to draw further conclusions for the operation of these systems in similar sites.
Homer’s Feasibility Analysis of a Hybrid System with a Grid Connection Option for the Mauritanian Northern Coast  [PDF]
Soukeyna Mohamed, Ismail Bidjel Ramdhane, Diene Ndiaye, Abdel Kader Mahmoud, Mohamed Elmamy, Mohamed Mahmoud Menou, Ahmed Mohamed Yahya, Issakha Youm
Journal of Power and Energy Engineering (JPEE) , 2019, DOI: 10.4236/jpee.2019.72003
Abstract: On Mauritania’s northern coast, wind and solar resources are abundant and must be used effectively. These resources have the potential to completely or partially replace the existing or projected diesel generators. The main objective of this case study is to study the possibility of using a hybrid system (HS) of the type (diesel, wind and storage). The most important part of this case study intended for this area will be to add the solar in a first phase and then the incorporation of an interconnection with the nearby network in a second phase. This interconnection will be secured by mean of medium voltage lines of 33 kV, where the nearest point is located 35 km away. Indeed, the study of the optimization model is carried out through Homer, which was developed by National Renewable Energy Laboratory [NREL]. Thus, it should be noted that the HS is analyzed on the basis of costs ($/kW) and price ($/kWh) and greenhouse gas emissions. Therefore, in order to achieve these techno-economic optimization objectives, this paper introduces a sensitivity analysis that has been proposed to determine the effect of costs on each HS configuration. In the end, HSs are needed for maximum use of renewable resources at the studied site for an uninterrupted power supply.
The Effects of Residual Blood of Carcasses on Poultry Technological Quality  [PDF]
Bourbab Mohamed, Idaomar Mohamed
Food and Nutrition Sciences (FNS) , 2012, DOI: 10.4236/fns.2012.310181
Abstract: The objective of this work is to show the effect of residual blood on the quality of chicken meat, work based on the hypothesis that increasing the concentration of residual blood would explain the observed quality degradation by several authors. Lots of chickens are killed with two different types of slaughter: Slaughter without stunning for a maximum flow of blood or bleeding perfect PS, shooting seals slight lead to keep almost all blood from the carcass or bleeding IS flawed. To prove the residual blood factors that are responsible for high pHu level and high values of (L* A* B*) in poultry, this study compares the pHu level and values of (L* A* B*) in poultry both perfectly and imperfectly bled. Samples from imperfectly bled carcasses show a high value average number of A* = 12.68 and B* = 16.85; and L* = 54.09 VS the average number of A* = 8.50 and B* = 14.43 and L* = 50.27. At 3℃ storage temperature, the average pHu of perfectly bled poultry was (5.7) which was significantly (P < 0.01) lower than the average pHu of imperfectly bled poultry (6.08). At 7℃ storage temperature, the average pHu of perfectly bled poultry was (6.07) which was significantly (P < 0.05) lower than the average pHu of imperfectly bled one (6.27). We found out the effect of season on the results of pHu measures, so we conducted aanalysis of pHu in summer and winter. Residual blood of the poultry is responsible for high values of (L* A* B*) and high values of pHu therefore the deterioration of the poultry Colour.
Monitoring of Temporal and Spatial Changes of Land Use and Land Cover in Metropolitan Regions through Remote Sensing and GIS  [PDF]
Mohamed Ali Mohamed
Natural Resources (NR) , 2017, DOI: 10.4236/nr.2017.85022
Abstract: The use of remote sensing techniques and subsequent analysis by means of geographical information system (GIS) offers an effective method for monitoring temporal and spatial changes of landscapes. This work studies the urbanization processes and associated threats to natural ecosystems and resources in the metropolitan areas of Berlin and Erlangen-Fürth-Nürnber?Schwabach (EFNS). To compute the land use/cover (LULC) of the study areas, a supervised classification of “maximum likelihood” using Landsat data for the years of 1972, 1985, 1998, 2003, and 2015 is used. Results show that the built-up area is the dominant land use in both regions throughout the study period. This land use has increased at the expense of green and open areas in EFNS and at the expense of agricultural land in Berlin. Likewise, 5% of forest in EFNS is replaced with urban infrastructure. However, the amount of forest in Berlin increased by 3%. While EFNS experienced relatively big changes in its water bodies from 1972 to 1985, changes in water bodies in Berlin were rather slight during the last 40 years. The overall accuracy of our remotely sensed LULC maps was between 88% and 94% in Berlin and between 85.87% and 87.4% for EFNS. The combination of remote sensing and GIS appears to be an indispensable tool for monitoring changes in LULC in urban areas and help improving LU planning to avoid environmental and ecological problems.
Analysis of Digital Elevation Model and LNDSAT Data Using Geographic Information System for Soil Mapping in Urban Areas  [PDF]
Mohamed Ali Mohamed
Natural Resources (NR) , 2017, DOI: 10.4236/nr.2017.812047
Abstract:
This study applies digital analysis methods of topographic data derived from digital elevation models (DEMs) and Landsat remotely sensed spectral data using GIS tools to evaluate the quality and limitations of the morphometric parameters (terrain attributes: TAs). This aims to check its suitability for digital soil mapping (DSM) and survey in urban areas at the target scale 1:50,000. This scale represents the standard scale level for compiling soil inventories within all German states. The study is conducted on an urban area of 112.68 km2 in the southwest part of the state of Berlin in Germany. These relief units are the basis for determining the soil mapping units at the scale of 1:50,000. The generated preliminary soil map was compared to soil maps made using traditional soil survey methods. For the mainly natural soils, the equivalence area is 94.91%, and for the anthropogenic soils, the equivalence area is 95.34%. The proposed methodology is adequate for preliminary mapping of soil units based on the digital derivation of TAs. Landsat scenes are spatially explicit, physical representations of environmental covariates on the land surface. The free DEM-ASTER in combination with Landsat OLI images is found to be the appropriate model to represent the terrain surface and derive the TAs for environmental modeling and fitting of derivation the relief units and their topography features. However, the 30 m spatial resolution and the fairly coarse spectral resolution of DEMs and Landsat images limit their utility for digital soil mapping at this scale in urban areas with little topographic variation.
Effect of Nalbuphine as Adjuvant to Bupivacaine for Ultrasound-Guided Supraclavicular Brachial Plexus Block  [PDF]
Mohamed Mohamed Abdelhaq, Mohamed Adly Elramely
Open Journal of Anesthesiology (OJAnes) , 2016, DOI: 10.4236/ojanes.2016.63004
Abstract: Background: Nalbuphine is a derivative of 14-hydroxymorphine which is a strong analgesic with mixed k agonist and μ antagonist. Nalbuphine was studied several times as adjuvant to local anesthetics in spinal, epidural and local intravenous block. The aim of this study was to evaluate the effect of nalbuphine as an adjuvant to local anesthetics in supraclavicular brachial plexus block. Patients and Methods: Fifty-six patients undergoing elective forearm and hand surgery under supraclavicular brachial plexus block were allocated randomly into one of two groups of 28 patients each to receive either 25 ml (0.5%) bupivacaine with 1 ml of NS or 25 ml (0.5%) bupivacaine with 1 ml (20 mg) nalbuphine. Onset time and duration of both sensory and motor block, and post-operative analgesia were observed. Result: Nalbuphine group showed significant increase in the duration of motor block (412.59 ± 18.63), when compared to control group (353.70 ± 29.019) p-value < 0.001, also, there was significant increase in sensory duration in nalbuphine group (718.14 ± 21.04) when compared to control group (610.18 ± 26.33) p-value < 0.001, without affecting the onset time of the blockade. And also, there was a significant increase in the duration of analgesic effect in nalbuphine group (835.18 ± 42.45) when compared to control group (708.14 ± 54.57) p-value < 0.001. Conclusion: The present study demonstrates that addition of 20 mg nalbuphine to bupivacaine in supraclavicular brachial plexus block is associated with significant increase in the duration of both sensory and motor block and also prolong the duration of analgesia.
Impact profenophos (pesticide) on infectivity of Biomphalaria alexandrina snails with schistosoma mansoni miracidiaand on their physiological parameters  [PDF]
Ragaa Mohamed
Open Journal of Ecology (OJE) , 2011, DOI: 10.4236/oje.2011.12005
Abstract: Profenophos is an organophosphorus pesticide which are used effectively against cotton insects and mites.The present work was carried out to evaluate the molluscicidal activity of pesticides (Profenophos) against Biomphalaria alexandrina snails. Also, the effect of sublethal concentrations of pesticide on the infection of B. alexandrina with Schistosoma mansoni and some enzymes of energy metabolism were studied. The results showed that the infection of B. alexandrina with schistosoma mansoni was greatly reduced after exposure to LC0, LC10, LC25 of pesticide and also, reduction in number of cercariae per snail during the patent period and in the period of cercarial shedding. The present study indicated that the increase in levels of aminotransaminases, acid phosphatase and alkaline phosphatases enzymes in haemolymph and soft tissue of snails and the activity level of lactate dehydrogenase, hexokinase and pyruvatekinase was also significantly reduced in response to treatment.
The Impact of the Imitation and Innovation Marketing in Services the Case of the Banks and Insurance  [PDF]
Mohamed Cherchem
Technology and Investment (TI) , 2012, DOI: 10.4236/ti.2012.32008
Abstract: Under current conditions of competition, it becomes more and more risk for a bank or an insurance company not to innovate. Customers expect a steady stream of new products and services [1-3]. The competition will certainly do its best to satisfy those desires. Continuous innovation is the only strategic choice to avoid loss of market share, many studies claim that the prosecution and the blind imitation of competitors and neglect of clients are the underlying reasons for many failures of new financial products [4,5]. This paper presents a framework for innovation in financial services and the consequences of imitation in terms of innovations in financial services. The study was conducted in two parts: the first part focuses on the concepts of innovation in services and the creative process and the implications as well as marketing and organizational success factors and causes of failures of new banking products and services and insurance, through a guide 26 maintains direct interview questions to each manager (regional directors) of banking and insurance. This paper proposes to shed light on this issue.
Stability and flocculation of nanosilica by conventional organic polymer  [PDF]
Mohamed Bizi
Natural Science (NS) , 2012, DOI: 10.4236/ns.2012.46052
Abstract: More than 2,000,000 tons of silica nanoparticles (NPs) are produced annually in the world to cover the needs of nanotechnologies. Inevitably, a quantity of NPs, will be in industrial discharges and domestic, or even in water resources. Share their high surface reactivity, these NPs may also carry with them through a specific adsorption of other toxic chemical pollutants inherent to the industrial sectors. To preserve public health and the environment from this pollution, it is necessary to remedy the potential pollution. In this context, the main motivation of this work is to answer this environmental issue by proposing a scheme of remediation based on the use of a conventional treatment process. The process of elimination nanoparticles by coagulation/flocculation was selected for its simplicity and also for its universal use. The NPs of industrial silica S30R50 were used as support to develop the process. The optimization of coagulation/flocculation, was greatly facilitated by the use of laser diffraction online. This technique allowed to follow the dynamic character of the treatment and to determine the size and the most relevant textural parameters (density, porosity and fractal dimension) of the flocs depending on the nature of the used reagents. The critical concentrations of different coagulants and flocculants used were determined by electrophoresis and turbidity. The ratio of their charge density/molecular weight has conditioned the quality of separation, the floc size and their texture. Excellent coagulation/flocculation performances are reached using organic reagents authorized by the Directorate General for Health of several countries. After optimization of the process, the size distributions are between 10 μm and 1 mm, with fractal dimensions (compactness) ranging from 2.3 to 2.5. The performances obtained show that the use of cationic polymers is a promising potential route to treat other types of NPs. The treatment proposed to reach a ratio of average diameters dFloc/dNP of 3500, and therefore it facilitates the elimination of these NPs agglomerated by filtration.
Investigation of Ground Frequency Characteristics  [PDF]
Mohamed Nayel
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2013, DOI: 10.4236/jemaa.2013.58050
Abstract:

Four-electrode method is one of the well-known methods in measuring ground resistivity. But, most faults currents and lightning currents have high frequencies components. It is proposed to develop this method to study ground frequency characteristics. A step like current was injected into ground to measure the ground impedance. The ground impedance is assumed to be frequency dependent parallel resistance/capacitance. Two equations were proved to estimate ground resistivity and permittivity from four-electrode method. An analytical model was proposed to model studied cases. The four electrodes are divided to equal spheres and complex image method had been used to satisfy the boundary conditions and penetration depth effects. The calculated results show good agreement with the measured results.

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