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Search Results: 1 - 10 of 10898 matches for " Mohamed Mahmoud Menou "
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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 Use of Intensity Modulated Radiotherapy as a Mean of Reducing Dose to Bone Marrow for Patients with Cancer Cervix Treated at Nci, Cairo, Egypt. Dosimetric Study  [PDF]
Mohamed Mahmoud, Mahmoud Shosha, Maha Hassan, Shaimaa Abdelgelil, Sandy Mohamed
Journal of Cancer Therapy (JCT) , 2017, DOI: 10.4236/jct.2017.810078
Abstract: Purpose: To test the use of Intensity Modulated Radiotherapy (IMRT) to spare the bone marrow (BM) in patients treated with cancer cervix through using the bone marrow an organ at risk. Patients and methods: Thirteen patients with stage (IB2-IIIB) intact cervix cancer were included; C-T simulation was done with contrast and full bladder with slice thickness 2.5 mm. Clinical Target Volume (CTV) included the cervix, uterus, upper half of the vagina, parametrium and regional lymph nodes. The CTV was expanded by 1 cm to form the Planning Target Volume (PTV). The organ at risk (OAR) included the bladder and rectum, the external contour of the pelvic bones to define the Pelvic Bone Marrow (PBM). Four plans were done for every patient with anteroposterior-posteroanterior (AP/PA), three dimensional conformal radiotherapy (3DCRT), IMRT, bone marrow-sparing intensity-modulated pelvic radiotherapy (BMS-IMRT). Results: BMS-IMRT reduced the V20, V30, V40 and V45 of the BM in comparison to 3DCRT and IMRT plans. Reduction in V20 with BMS-IMRT plan compared to 3DCRT (p < 0.03). The PBM volume receiving 5, 10 and 20 Gy was lower AP/PA than BMS-IMRT (p < 0.01, p < 0.001 and p < 0.04 respectively). The volumes of the rectum
Valuation and Determination of Seven and Five Parameters of Photovoltaic Generator by Iterative Method  [PDF]
Ahmed Yahfdhou, M. M. Menou, A. M. Yahya, Ne. D. Eida, A. K. Mahmoud, Issakha Youm
Smart Grid and Renewable Energy (SGRE) , 2016, DOI: 10.4236/sgre.2016.79019
Abstract: The mathematical modeling of solar cells is essential for any optimization operation of the efficiency or the diagnosis of photovoltaic generator. The photovoltaic module is generally represented by an equivalent circuit whose parameters are experimentally calculated by using the characteristic current-tension, I-V. The precise determination of these parameters stays a challenge for the researchers, making to a big difference in the models and the digital methods dedicated to their characterizations. In the present paper, We are interested to characterize the parameters of single diode and two diodes models, in order to plan the behavior of the photovoltaic generator under real functioning conditions. We developed an identification method of the parameters using Newton Raphson method by using the software Matlab/Simulink. This method is the faster technique which allows the identification of several parameters and can be used in real time applications. The results of the proposed method show an accordance with the experimental and simulated characteristics of photovoltaic generator.
Studies of Electron Energy Distribution Function (EEDF) in Lithium Vapor Excitation at 2S→3D Two-Photon Resonance  [PDF]
Mohamed A. Mahmoud, Kholoud A. Hamam
Optics and Photonics Journal (OPJ) , 2014, DOI: 10.4236/opj.2014.48020
Abstract:

We have developed a computational model which quantitatively studies the Electron Energy Distribution Function (EEDF) in laser excited lithium vapor at 2s→3d two-photon resonance. A kinetic model has been constructed which includes essentially all the important collisional ionization, photoionization, electron collisions and radiative interactions that come into play when lithium vapor (density range 1013 - 1014 cm-3) is subject to a sudden pulse of intense laser radiation (power range 105 - 106 W·cm-2) at wavelength 639.1 nm and pulse duration 20 ns. The applied computer simulation model is based on the numerical solution of the time-dependent Boltzman equation and a set of rate equations that describe the rate of change of the formed excited states populations. Using the measured values for the cross-sections and rate coefficients of each physical process considered in the model available in literature, relations are obtained as a function of the electron energy and included in the computational model. We have also studied the time evolution and the laser power dependences of the ion population (atomic and molecular ions) as well as the electron density which are produced during the interaction. The energy spectra of the electrons emerging from the interaction contains a number of peaks corresponding to the low-energy electrons produced by photoionization and collisional ionization such as assosicative and Penning ionization processes. The non-equilibrium shape of these electrons occurs due to relaxation of fast electrons produced by super-elastic collisions with residual excited lithium atoms. Moreover, a reasonable agreement between McGeoch results and our calculations for the temporal behaviour of the electron density is obtained.

Inverse Nonnegativity of Tridiagonal M-Matrices under Diagonal Element-Wise Perturbation  [PDF]
Mohamed A. Ramadan, Mahmoud M. Abu Murad
Advances in Linear Algebra & Matrix Theory (ALAMT) , 2015, DOI: 10.4236/alamt.2015.52004
Abstract: One of the most important properties of M-matrices is element-wise non-negative of its inverse. In this paper, we consider element-wise perturbations of tridiagonal M-matrices and obtain bounds on the perturbations so that the non-negative inverse persists. The largest interval is given by which the diagonal entries of the inverse of tridiagonal M-matrices can be perturbed without losing the property of total nonnegativity. A numerical example is given to illustrate our findings.
Generating Totally Positive Toeplitz Matrix from an Upper Bidiagonal Matrix  [PDF]
Mohamed A. Ramadan, Mahmoud M. Abu Murad
Advances in Linear Algebra & Matrix Theory (ALAMT) , 2015, DOI: 10.4236/alamt.2015.54014
Abstract: In this paper, we construct one of the forms of totally positive Toeplitz matrices from upper or lower bidiagonal totally nonnegative matrix. In addition, some properties related to this matrix involving its factorization are presented.
Nonlinear Control of Chaotic Forced Duffing and Van der Pol Oscillators  [PDF]
Mohammed Alghassab, Amr Mahmoud, Mohamed A. Zohdy
International Journal of Modern Nonlinear Theory and Application (IJMNTA) , 2017, DOI: 10.4236/ijmnta.2017.61003
Abstract: This paper discusses a novel technique and implementation to perform nonlinear control for two different forced model state oscillators and actuators. The paper starts by discussing the Duffing oscillator which features a second order non-linear differential equation describing complex motion whereas the second model is the Van der Pol oscillator with non-linear damping. A first order actuator is added to both models to expand on the chaotic behavior of the oscillators. In order to control the system without comprising linearization, Lyapunov non-linear control was used. A control Lyapunov function was tailored to the system. This led to improved maneuverability of the controller and the performance of the overall system. The controller was found to be highly efficient in system tracking and had swift response time. Simulations were performed on both the uncontrolled and controlled cases. Both simulation results ultimately confirmed the effectiveness of the proposed controller.
Quranic Verse No. 8 of Surat Al-Jumu’ah Describes Cancer as a Complete and Accurate Description and Leads Us to Determine the True Cause of Cancer. “Part-1”  [PDF]
Mahmoud Saad Mohamed El-Khodary
CellBio (CellBio) , 2018, DOI: 10.4236/cellbio.2018.71001
Abstract: Cancer is the cell fleeing from death by blocking the pathways of the intrinsic and the extrinsic program of cell death (Apoptosis). The success depends on making the programs of cell death run again.
Henry Reaction between Benzaldehyde and Nitromethane over Solid Base Catalysts: A Green Protocol  [PDF]
Magda H. Abdellattif, Hany Mahmoud Mohamed
Green and Sustainable Chemistry (GSC) , 2018, DOI: 10.4236/gsc.2018.82010
Abstract: The development of environmentally benign solid base catalysts instead of the soluble bases for C-C bond formation in organic reactions especially Henry reactions with nitroalkanes compounds is of intense research activity in the bulk and fine chemical chemistry in order to achieve the selectivity of the desired product and the reduction of the salts formed due to soluble bases neutralization. While using of LDHs catalysts in the synthesis of nitro alcohols is of great interest because LDHs (double layered hydroxides) is of unique properties and an excellent catalytic property. The nitroalcohols are obtained in a very good yield while using catalyst either by conventional at 90°C in liquid phase, microwave or sonoenergy without solvent methods, and the results yields are compared. A series of different nitro alcohols from (a - o) were prepared, the catalytic test reaction were carried out using benzaldehyde and their derivatives with nitromethane and their derivatives. A series of LDHs catalysts were prepared also and studying of the catalytic effect on the reactions was carried out. Properties of the compounds prepared were characterized by IR, MNR, and GC-MS.
Quranic Verse No. 8 of Surat Al-Jumu’ah Leads Us to Describe Cancer and Determine its True Cause (Part-II)  [PDF]
Mahmoud Saad Mohamed El-Khodary
CellBio (CellBio) , 2018, DOI: 10.4236/cellbio.2018.72002
Abstract: Cancer is cell fleeing from death by blocking the intrinsic and extrinsic programs of cell death. The six elements that shut down those programs are: muc-1, muc-4, muc-16, Bcl-2, MMPs and decoy R3. The nuclear factor-kappa B (NF-Kb) stimulates the expression of genes responsible for the production of those elements, which are used by cells to block those two programs. In other words, the nuclear factor kappa B (NF-KB) is responsible for blocking both programs. Therefore, the nuclear factor kappa B (NF-Kb) is the true cause of cancer.
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