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Search Results: 1 - 10 of 23131 matches for " Mohamed Abd El-Aziz "
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Influence of Charcoal Broiled Meat Consumption on the Liver Functions and Non-Enzymatic Antioxidants in Human Blood  [PDF]
Yousif Abd El-Aziz Elhassaneen, Amal Mohamed El-Badawy
Food and Nutrition Sciences (FNS) , 2013, DOI: 10.4236/fns.2013.41013
Abstract:

The effect of ingesting charcoal-broiled beefburgers (CBB) on the liver functions and nonenzymatic antioxidant levels in human blood was examined in twenty-nine healthy individually males (mean age 21.65 ± 1.32 years, range 20.32 - 22.42 years), non-smokers and had no occupational exposure to PAHs, who consumed two charcoal grilled beefburger per day (mean weight 70 gmper each) at lunch time over 28 consecutive days. The mean daily intake of PAH during the consumption period was 3431 ng and the mean daily intake of PAH per kg body wt/day was 46 ng. Blood samples were collected from each subject 7, 14, 21 and 28 days before, during, and after the beefburgers consumption period. glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvate transaminase (GPT) and alkaline phosphatase (ALP) were significantly higher in serum of subjects during CBB consumption period compared with those of before CBB consumption ones. All of the enzyme activities still increased upper the baseline levels, before CBB consumption period, by four week after charcoal broiled meat consumption ended. In contrary, the levels of non-enzymatic antioxidants include albumin (ALB), glutathione in serum (GSH-S) and erythrocytes (GSH-E) were significantly lower in subjects during CBB consumption period compared with those of before CBB consumption ones. All of the non-enzymatic antioxidant levels decreased to near baseline levels, before CBB consumption period, by four week after charcoal broiled meat consumption ended. Results suggested that non-enzymatic antioxidants defense system of serum and erythrocytes was depressed and the erythrocytes as well as liver cells were exposed to oxidant stress due to oral exposure of PAH.

Design and Analysis of an OSA-BR MAC Protocol for Cognitive Radio Ad Hoc Networks  [PDF]
Hassan Al-Mahdi, Mohamed Wahed, Safa Abd El-Aziz
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2014, DOI: 10.4236/ijcns.2014.77024
Abstract:

Cognitive Radio (CR) is a new communication network paradigm introduced to solve the problems of spectrum scarcity and inefficient spectrum usage. Basically, it allows the Secondary Users (SUs) to utilize the Licensed Channels (LCs) of the Primary Users (PUs) in an opportunistic manner without causing any harmful interference to the PUs. However, there are many challenges associated with cognitive radio networks, such as the CR Medium Access Control (CR-MAC) protocols. An important issue for CR-MAC protocols is to identify whether the spectrum is licensed or unlicensed. In addition, the sudden appearance of the PU is the most important feature of the distributed CR-MAC protocols. In this paper, a multichannel CR-MAC protocol, which reacts efficiently to the appearance of the PUs, is developed. The proposed protocol is named Opportunistic Spectrum Access with backup channel and Buffered data with Resume (OSA-BR). The OSA-BR is an unaided rendezvous, asynchronous, and contention-based MAC protocol. The proposed protocol operates in heterogeneous environment, where the SUs utilize both LCs and unlicensed channel (ULs) and the activities of the Classical Users (CUs) are taken into consideration. In addition, the concept of the backup channel and the buffer with resume are introduced. The simulation results show that OSA-BR accomplishes 35% throughput gain over the SWITCH protocol and 55% over other CR-MAC protocols.

Fabrication, Microstructure, Thermal and Electrical Properties of Copper Heat Sink Composites  [PDF]
Walid Daoush, Ahmed Swidan, Gamal Abd El-Aziz, Mohamed Abdelhalim
Materials Sciences and Applications (MSA) , 2016, DOI: 10.4236/msa.2016.79046
Abstract: Copper as well as copper base composites reinforced with coated and uncoated 1 wt% diamond, graphite particles or short carbon fibers are prepared by powder metallurgy process. The reinforcement particles were encapsulated with silver as well as copper layer by using the electroless deposition technique to investigate the influence of the reinforcement surface coating on the microstructure, density, electrical and thermal properties of the sintered samples. The coated and the uncoated powders were cold compacted at 600 MPa, and then sintered at 1173 K (900°C) for 2 h under hydrogen atmosphere. The phase composition, morphology and microstructure of the prepared powders as well as the copper base sintered composites were investigated using X-ray diffraction analysis (XRD) and Scanning Electron Microscope (SEM) equipped with an Energy Dispersive Spectrometer (EDS) respectively. The density of the sintered composites was measured by Archimedes method. The copper base consolidated composites had a density up to 96% and the reinforcement coated particles were distributed uniformly within the copper matrix better than the uncoated one. The electrical resistivity at room temperature and the heat transfer conduction of the produced samples were measured in a temperature range between 323 K (50°C) and 393 K (120°C). The results observed that the sintered materials prepared from the coated powder have lower electrical resistivity than the sintered materials prepared from the mixed powders. On the other hand the thermal conductivity values were calculated using the heat transfer conduction values by means of the Fourier formula. The results observed that the thermal conductivity of copper is (391 W/m·K), 1 wt% diamond/Cu is (408 W/m·K), 1 wt% graphite coated silver/Cu is (393 W/m·K), 1 wt% Cu coated short carbon fiber/Cu is (393 W/m·K), graphite/Cu is (383 W/m·K) and short carbon fiber/Cu is (382 W/m·K). The obtained composites are expected to be suitable for heat sink applications. The heat transfer testing experiments were done. The forced convection of the present work was done and compared with the previous work in the literature, and satisfactory agreement was achieved.
Homotopy Analysis Solution of Hydromagnetic Mixed Convection Flow Past an Exponentially Stretching Sheet with Hall Current
Mohamed Abd El-Aziz,Tamer Nabil
Mathematical Problems in Engineering , 2012, DOI: 10.1155/2012/454023
Abstract: The effect of thermal radiation on steady hydromagnetic heat transfer by mixed convection flow of a viscous incompressible and electrically conducting fluid past an exponentially stretching continuous sheet is examined. Wall temperature and stretching velocity are assumed to vary according to specific exponential forms. An external strong uniform magnetic field is applied perpendicular to the sheet and the Hall effect is taken into consideration. The resulting governing equations are transformed into a system of nonlinear ordinary differential equations using appropriate transformations and then solved analytically by the homotopy analysis method (HAM). The solution is found to be dependent on six governing parameters including the magnetic field parameter M, Hall parameter m, the buoyancy parameter , the radiation parameter R, the parameter of temperature distribution a, and Prandtl number Pr. A systematic study is carried out to illustrate the effects of these major parameters on the velocity and temperature distributions in the boundary layer, the skin-friction coefficients, and the local Nusselt number.
Effect of Catharanthus roseus (Vince rosea) and Turmeric (Curcuma longa) Extracts as Green Corrosion Inhibitors for Mild Steel in 1 M HCl  [PDF]
Rabab Mohamed Abou Shahba, Abd El-Aziz El-Sayed Fouda, Azza El-Sayed El-Shenawy, Amina Salah Mohamed Osman
Materials Sciences and Applications (MSA) , 2016, DOI: 10.4236/msa.2016.710053
Abstract: The corrosion inhibition of mild steel by Catharanthus roseus (Vince rosea) and Turmeric (Curcuma longa) extracts as green inhibitors in 1 M HCl solutions has been investigated by using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), hydrogen evolution measurements and scanning electron microscope (SEM) techniques. Results obtained show that these investigated compounds are good inhibitors and act as mixed type inhibitors. The inhibition efficiencies increase with increasing inhibitor concentration. The SEM results show the formation of protective film on the mild steel surface in the presence of Catharanthus roseus and Turmeric extracts. The results obtained from different tested techniques are in good agreement.
Monitoring and Change Detection along the Eastern Side of Qena Bend, Nile Valley, Egypt Using GIS and Remote Sensing  [PDF]
Ahmed Omar Abd El-Aziz
Advances in Remote Sensing (ARS) , 2013, DOI: 10.4236/ars.2013.23030
Abstract:

This Article is set to track and monitor changes through spatial dependence of remote sensing data and GIS analysis, the suggested working method in this research is by sub pixel classification techniques. Change detection is a central task for land cover monitoring by remote sensing. It uses multi temporal image data sets in order to detect land cover changes from spectral discrepancies [1] (Rafael, et al.). It discusses the study perception of the situation in the past as well as the current and finally the future status of changes that land uses in Eastern Qena meander specifically in places of estuary floods, and the most important estuary leading to Qena, and whether these changes in land are used in direction of the mouth of the stream or not, especially that when it happened before, it caused destruction of both activities, urban & agricultural land. It will rely on Landsat images in years of (1972-2012), conduct analysis, different classifications integration with geographic information systems (GIS), and field as well as samples for the accuracy assessment.


Performance Evaluation of Mobility Speed over MANET Routing Protocols
Yasser Kamal Hassan,Mohamed Hashim Abd El-Aziz,Ahmed Safwat Abd El-Radi
International Journal of Network Security , 2010,
Abstract: Ad-hoc networking is a concept in computer communications. Each node participating in the network acts both as host and a router and must therefore is willing to forward packets for other nodes. Research in this area is mostly simulation based; Random waypoint is the commonly used mobility model in these simulations. Random waypoint is a simple model that may be applicable to some scenarios. In the performance evaluation of a protocol for MANETs, the protocol should be tested under realistic conditions including. In recent years, a variety of routing protocols targeted specifically at this environment have been developed and some performance simulations are made on numbers of routing protocols likes DSDV, DSR and AODV, Research efforts haven't focused much in evaluating their performance when applied to variable number of nodes and constant pause times, We perform extensive simulations using NS-2 simulator, which carried out based on the Rice Monarch Project.
Application of Modified Bagasse as a Biosorbent for Reactive Dyes Removal from Industrial Wastewater  [PDF]
Abd El-Aziz A. Said, Aref A. M. Aly, Mohamed M. Abd El-Wahab, Soliman A. Soliman, Aly A. Abd El-Hafez, V. Helmey, Mohamed N. Goda
Journal of Water Resource and Protection (JWARP) , 2013, DOI: 10.4236/jwarp.2013.57A003
Abstract:

Propionic acid modified bagasse was used for the removal of reactive yellow 2 and reactive blue 4. The effects of pH, contact time, initial dye concentrations, adsorbent particle size and adsorbent dose on the adsorption of the two dyes were investigated. Additionally, the desorption process and intra-particle diffusion were studied. Acidic pH values were favorable for adsorption of both dyes. The equilibrium adsorption data were best fitted with the Freundlich isotherm for reactive yellow 2 and the Langmiur isotherm for reactive blue 4. The values of their corresponding constants were determined. The kinetic for dye adsorption is well described by a pseudo-first order kinetic model for the reactive yellow 2 and by pseudo-second order for the reactive blue 4. The investigation revealed that the hydroxyl groups of bagasse and the carboxylic group of propionic acid play a great role in the removal of both reactive dyes.

Optical Code Division Multiple Access Performance Signature Over Multimode Optical Fiber Transmission Systems
Ahmed Nabih Zaki Rashed,Mohamed M. Zahra,Mohamed Yassin,Ismail A. Abd El-Aziz
International Journal of Advanced Research in Computer Science and Electronics Engineering , 2013,
Abstract: This paper has focused on the performance of an optical code division multiple access (OCDMA) system over multi mode optical fiber transmission systems and the transmission efficiency to be evaluated in order to determine the impact of multi access interference for a given number of users. It has recently attracted significant research interest because of the advantages it offers in terms of the flexibility in the management of the system resources. The optimum system design parameters are determined at a specific BER (bit error rate) with average repeater spacing and signal to noise ratio over multi mode fibers transmission systems for short, indoor and long applications.
Mixture of Generalized Gamma Density-Based Score Function for Fastica
M. EL-Sayed Waheed,Osama Abdo Mohamed,M. E. Abd El-aziz
Mathematical Problems in Engineering , 2011, DOI: 10.1155/2011/150294
Abstract: We propose an entirely novel family of score functions for blind signal separation (BSS), based on the family of mixture generalized gamma density which includes generalized gamma, Weilbull, gamma, and Laplace and Gaussian probability density functions. To blindly extract the independent source signals, we resort to the FastICA approach, whilst to adaptively estimate the parameters of such score functions, we use Nelder-Mead for optimizing the maximum likelihood (ML) objective function without relaying on any derivative information. Our experimental results with source employing a wide range of statistics distribution show that Nelder-Mead technique produce a good estimation for the parameters of score functions.
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