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Search Results: 1 - 10 of 1094 matches for " Hamed Shekarchizade "
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Effect of Elemental Composition on the Structure, Electrochemical Properties, and Ozone Production Activity of Ti/Sn -Sb-Ni Electrodes Prepared by Thermal Pyrolysis Method
Hamed Shekarchizade,Mohammad K. Amini
International Journal of Electrochemistry , 2011, DOI: 10.4061/2011/240837
Abstract: Ti/SnO2-Sb-Ni electrodes with various Ni- and Sb-doping levels have been prepared by dip-coating thermal pyrolysis procedure, and their simultaneous electrochemical ozone production (EOP) and oxygen evolution reaction (OER) were investigated. The effects of electrode composition on the nanostructure, morphology, electrochemical behavior, kinetic parameters, and lifetime of the electrodes were systematically studied using X-ray diffraction, scanning electron microscopy, cyclic voltammetry, linear sweep voltammetry, and chronopotentiometry. Dissolved ozone was produced in a quartz cell and its concentration was monitored by in situ UV spectrophotometry. The presence of small amounts of Ni (Ni?:?Sn atomic ratio of 0.2?:?100) gives valuable characteristics to the electrodes such as increasing EOP activity and service life. Higher Ni concentrations increase the electrode film resistance and decrease its capacitance, roughness factor, and service life, while increasing Sb level up to 12 atom% improves the electrode performance with respect to these parameters. Nevertheless, the Sb/Sn atomic ratio of more than 2% reduces the EOP current efficiency in favor of OER. The optimum composition of the electrode for EOP was determined to be Sb/Sn and Ni/Sn atomic ratios of 2% and 0.2%, respectively. The highest current efficiency was 48.3% in 0.1?M H2SO4 solution at room temperature. 1. Introduction Ozone (O3), as an environmentally friendly reagent with high oxidizing power, has found a broad range of applications in various fields such as water and wastewater treatment, sterilization of surgical equipments, bleaching processes, cleaning of semiconductor materials, and chemical synthesis [1–5]. There are two main methods for preparation of dissolved ozone: corona discharge followed by dissolving ozone into solution and electrolysis [6]. The latter method has the advantages of being a simple process which produces relatively high concentrations of ozone directly into solution without producing harmful nitrogen oxides and without need for a high voltage power source as compared to corona discharge. The OER (1) is thermodynamically more favorable and severely competes with EOP (2) on the anode of an electrochemical ozone generator. Consequently, minimizing OER is a key requirement for EOP with a reasonable current efficiency. This can be achieved by suitable choice of the anode material to have a high overpotential for OER. In addition, the anode should have good conductance, high durability under drastic operating conditions, and particularly good electrocatalytic
XUV and Soft X-Ray Laser Radiation from Ni-Like Au  [PDF]
Wessameldin S. Abdelaziz, Hamed Mahmoud Hamed Ibrahim
Optics and Photonics Journal (OPJ) , 2011, DOI: 10.4236/opj.2011.13019
Abstract: Atomic structure data and effective collision strengths from literature for 1s2 2s2 2p6 3s2 3p63d10 and 34 fine-structure levels contained in the configurations 1s2 2s2 2p6 3s2 3p63d9 4l (l = s, p, d) for the nickel-like Au ion are used in the determination of the reduced population for these levels over a wide range of electron densities and at various electron plasma temperatures. The gain coefficient for those transitions with positive population inversion factor are determined and plotted against the electron density.
Computer Generated Quadratic and Higher Order Apertures and Its Application on Numerical Speckle Images  [PDF]
Abdallah Mohamed Hamed
Optics and Photonics Journal (OPJ) , 2011, DOI: 10.4236/opj.2011.12007
Abstract: A computer generated quadratic and higher order apertures are constructed and the corresponding numerical speckle images are obtained. Secondly, the numerical images of the autocorrelation intensity of the randomly distributed object modulated by the apertures and the corresponding profiles are obtained. Finally, the point spread function (PSF) is computed for the described modulated apertures in order to improve the resolution.
Scanning Holography Using a Modulated Linear Pupil: Simulations  [PDF]
Abdallah Mohamed Hamed
Optics and Photonics Journal (OPJ) , 2011, DOI: 10.4236/opj.2011.12008
Abstract: In this paper an electron microscopic image of diameter 80 – 120 nm and of dimensions 180×220 pixels is used as a test object to fabricate Fresnel zone plate hologram. The author proposes a different set of pupils: one pupil still being a delta function and the other being a function of < r > = sqrt(x2+y2). The obtained reconstructed images in case of scanning holography are investigated.
Recognition of Direction of New Apertures from the Elongated Speckle Images: Simulation  [PDF]
Abdallah Mohamed Hamed
Optics and Photonics Journal (OPJ) , 2013, DOI: 10.4236/opj.2013.33040
Abstract:

In this paper, we present an elongated speckle images produced from diffusers using sharp elliptical apertures. The orientation of the elliptic aperture is recognized from the direction of the elongation in the speckle images. The aperture tilting out of the plane is investigated. Three models of elliptical apertures are considered and the corresponding speckle images are obtained. The 1st model is composed of two orthogonal ellipses or plus symbol pupil; the 2nd has four symmetric ellipses with an angle of 45° between each of them or in the form of a snow flake pupil and the 3rd model looks like an airplane. Also, the autocorrelation profiles of the speckle images corresponding to the diffused airplane are obtained from which the average speckle size is computed. Finally, the reconstructed images of the described elliptical models and its autocorrelation images, making use of Mat lab code, are obtained.

A Series Solution for Three-Dimensional Navier-Stokes Equations of Flow near an Infinite Rotating Disk  [PDF]
Hamed Shahmohamadi, Mahdi Mohammadpour
World Journal of Mechanics (WJM) , 2014, DOI: 10.4236/wjm.2014.45014
Abstract:

In this paper, homotopy analysis method (HAM) and Padé approximant will be considered for finding analytical solution of three-dimensional viscous flow near an infinite rotating disk which is a well-known classical problem in fluid mechanics. The solution is compared to the numerical (fourth-order Runge-Kutta) solution and the convergence of the obtained series solution is carefully analyzed. The results illustrate that HAM-Padé is an appropriate method in solving the systems of nonlinear equations.

Can Macroinvertebrate Assemblage Changes Be Used as Biological Indicator of Water Quality of the Nokoue Lake (Benin)?  [PDF]
Hamed Odountan, Youssouf Abou
Journal of Environmental Protection (JEP) , 2015, DOI: 10.4236/jep.2015.612122
Abstract: Investigations on biological capacity of water quality of macroinvertebrate community are very uncommon, and such as the amount of information available on the Nokoue Lake (the largest lake of Benin) is very limited. This information gap needs to be filled for better management of the Nokoue Lake. The goal of this study was to evaluate the possibility of using the macroinvertebrate community structures in Nokoue Lake and the environmental factors responsible for the maintenance of these structures. Nokoue Lake was studied over three months, during high flood period in which time subsurface water and macroinvertebrate samples were collected and analyzed. A study showed that the macroinvertebrate assemblages was done according to ecological gradients as pH, conductivity, TDS, salinity, chlorophyll a and probably to anthropogenic actions (nutriments). Better than the percentage of insects, the percentage of Chironomidae informed very well about macroinvertebrate assemblages. To assess the biological health of the environment, the Family Biotic Index (FBI) turns out to be more appropriate than diversity indices that do not take into account the intermediate pollution. Organic pollution revealed by the FBI probably affects the aquatic life.
Ameliorative Effects of Spirulina platensis on Deltamethrin-Induced Biochemical Alterations and Oxidative Stress in the African Catfish; Clarias gariepinus  [PDF]
Heba S. Hamed
Open Journal of Marine Science (OJMS) , 2016, DOI: 10.4236/ojms.2016.61001
Abstract: The present study was carried out to determine LC50 of deltamethrin (DM) in the African catfish; Clarias gariepinus, investigate its effects on the biochemical parameters and the antioxidant status of various tissues, and assess the protective role of Spirulina platensis (SP) against DM induced toxicity in C. gariepinus. The fish were distributed into seven groups of 10 fish/each for 30 days as follows: Group 1, control; Group 2, orally administered saline; Group 3, oral SP (150 mg/kg b.w.); Group 4, exposed to 5.19 μg/l DM; Group 5, exposed to 5.19 μg/l DM and orally administered SP (150 mg/kg b.w.); Group 6, exposed to 12.97 μg/l DM; and Group 7, exposed to 12.97 μg/l DM and orally administered SP (150 mg/kg b.w.). Results revealed marked elevation in serum AST, ALT, ALP, creatinine, urea and uric acid. Significant decrease in serum total protein and albumin was recorded. At the same time, the level of malondialdehyde (MDA) was significantly increased in liver, kidney and gills. While, tissue level ofGSHand, SOD,CATandGSH-Px activities were reduced. Treatment with SP improved the biochemical parameters and attenuated the DM induced oxidative damage. Therefore, this study confirmed the protective role of SP as an antioxidant against the toxicity of DM in catfish.
Structure and Composition of Macroinvertebrates during Flood Period of the Nokoue Lake, Benin  [PDF]
Hamed Odountan, Youssouf Abou
Open Journal of Ecology (OJE) , 2016, DOI: 10.4236/oje.2016.62007
Abstract: The Nokoue Lake is the largest lake of Benin Republic and it is also considered as one of the most productive lagoon ecosystems in West Africa. This productivity is decreasing and thus raises productivity issue for a better management and conservation. Macroinvertebrate can be useful for this purpose. A study was conducted to assess the spatial variation of macroinvertebrates during high flood period. A total of 3892 macroinvertebrates of fresh and brackish water were sampled during the survey. Structural analysis of the macroinvertebrate community revealed that it was made up of 16 orders, 48 families and 66 genera dominated by Insecta compared to Mollusca, Crustacea and the Annelida. Insects were dominated by Diptera (Chironomus sp. and Tanytarsus sp.), Coleoptera (Dystiscidae) and accounted for 57.1% of the sampled population. Mollusca, Crustacea, Annelida and Arachnida were the following most abundant and represented 23.9%, 10.7%, 8.1% and 0.2% of the total population, respectively. The Evenness index of Pielou was higher on the Station 8 (0.91 - 0.97), close to Oueme River. However, no significant difference (p > 0.05) was observed neither between station nor between month on the Shannon-Wiener index (2.06 - 4.31), Simpson index (0.04 - 0.40) and the taxa number (10 - 27). Macroinvertebrate assemblages and composition were primarily due to changes in water quality dependent on hydroclimatic changes and probably to anthropogenic actions. This suggests the need for real investigation of the macroinvertebrate biological capacity when formulating conservation strategies for the Nokoue Lake.
Fuzzy PID Controllers Using FPGA Technique for Real Time DC Motor Speed Control  [PDF]
Basil Hamed, Moayed Almobaied
Intelligent Control and Automation (ICA) , 2011, DOI: 10.4236/ica.2011.23028
Abstract: The design of intelligent control systems has become an area of intense research interest. The development of an effective methodology for the design of such control systems undoubtedly requires the synthesis of many concepts from artificial intelligence. The most commonly used controller in the industry field is the proportional-plus-integral-plus-derivative (PID) controller. Fuzzy logic controller (FLC) provides an alternative to PID controller, especially when the available system models are inexact or unavailable. Also rapid advances in digital technologies have given designers the option of implementing controllers using Field Programmable Gate Array (FPGA) which depends on parallel programming. This method has many advantages over classical microprocessors. In this research, A model of the fuzzy PID control system is implemented in real time with a Xilinx FPGA (Spartan-3A, Xilinx Company, 2007). It is introduced to maintain a constant speed to when the load varies.,The model of a DC motor is considered as a second order system with load variation as a an example for complex model systems. For comparison purpose, two widely used controllers “PID and Fuzzy” have been implemented in the same FPGA card to examine the performance of the proposed system. These controllers have been tested using Matlab/Simulink program under speed and load variation conditions. The controllers were implemented to run the motor as real time application under speed and load variation conditions and showed the superiority of Fuzzy-PID.
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