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Ahmed G.E.,Asuit University | Mohmed Y.S.,Minia University | Kamel O.M.,Electrical and Computer Dep.
2016 18th International Middle-East Power Systems Conference, MEPCON 2016 - Proceedings | Year: 2016

Harnessing wind energy for producing electrical power becomes vital and essential now a day in our communities. However the large penetration of wind farms into the electrical power grid affects the dynamic performance of grid especially during abnormal conditions. STATCOM FACTS device is employed for mitigation the voltage sage and improving power quality at the point of common coupling (PCC) where large scale wind power plants (WPP) are connected to grid during faults period. PI regulators with classical gain tuning are the most common procedure used for controlling the STATCOM performance. In this paper the particle swarm optimization (PSO) and ant colony optimization (ACO) as evolutionary methods are adopted to obtain flexible and reliable PI parameter tuning for cogging and improving STATCOM dynamic behavior during voltage sage occurrence. The main contribution of using STATCOM is to obtain an adequate fault ride through for wind driven doubly fed induction generator that can track the grid code requirements. So the impacts of deep voltage sage introduced to 9 MW wind farm DFIG and connected to 120 kV power grid are investigated by using Matlab/Simulink program. Results obtained show the effectiveness of the proposed PSO and ACO methodologies. © 2016 IEEE.

Ahmed G.E.,Asuit University | Mohmed H.A.,HIGH-TECH | Kamel O.M.,HIGH-TECH
2016 18th International Middle-East Power Systems Conference, MEPCON 2016 - Proceedings | Year: 2016

This paper presents a voltage vector control method based on space vector modulation to govern both the RSC and GSC of a wind driven DFIG during non-severe voltage conditions specially unbalanced faults. The main contribution of this work is to provide an effective voltage vector control that can mitigate problems caused by the unbalanced non-sever faults by making co-ordination between the RSC and the GSC without using any external elements. Simulation results obtained prove that the proposed control system has a fast dynamic response and improves the DFIG stability by decreasing torque pulsation, reducing ripples of the dc-link voltage of back to back converter and making the recovery time less. The results are compared to the conventional PI regulator method used for controlling the back-to-back converters of the DFIG and the proposed technique proves its compactness and robustness for providing better dynamic performance. © 2016 IEEE.

Attalla M.,South Valley University | Ahmed H.,Asuit University | Ahmed M.S.,Sohag University | El-Wafa A.A.,Qarun Petroleum Company
Applied Thermal Engineering | Year: 2017

The present study investigated experimentally the cooling and heating performance of two identical counter flow vortex tubes arranged in-series (VTS) and parallel (VTP). The vortex tube used has general specifications of: aspect ratio AR = 1.6, hot tube length L = 112.5 mm, hot tube inner diameter D = 7.5 mm, cold end diameter dc = 5 mm, and generator of three nozzles, N = 3. Dry air is used as a working fluid with different inlet air pressures adjusted from 2 to 6 bars. The experimental results revealed that the maximum cold temperature difference occurred at the inlet air pressure of 6 bars and cold mass fraction of 0.4 for both VTS and VTP systems. The conducted results demonstrated that the values of COPref for VTS system were higher than the values of VTP system. However, the VTP yielded higher values of COPHP over the range of investigation. The VTS system improved the COPref by 22.5% and 31.5% compared with the VTP and the single vortex tube system (VTO), respectively. For the case of VTP system, the COPHP is enhanced by 18.2% and 27.3% than VTS and VTO, respectively. © 2017 Elsevier Ltd

Hussein A.E.M.A.,Aswan University | Mahfouz H.,Al - Azhar University of Egypt | Elazeem K.A.,Menoufia University | Fakhry M.,Al - Azhar University of Egypt | And 13 more authors.
Medicine (United States) | Year: 2015

In countries endemic for liver and GIT diseases, frequent emergency department (ED) patients contribute to a disproportionate number of visits consuming substantial amount of medical resources. One of the most frequent ED visits is patients who present with hypovolemic shock, abdominal pain, or confusion with or without signs of upper gastrointestinal bleeding (UGIB). The use of conventional twodimensional ultrasound (2D-U/S) may provide immediate and useful information on the presence of esophageal varices, gastrointestinal tumors, and other GIT abnormalities. The current study investigated the feasibility of using (2D-U/S) to predict the source of UGIB in ED and to determine patients' priority for UGE. Between February 2003 and March 2013, we retrospectively reviewed the profiles of 38,551 Egyptian patients, aged 2 to 75 years old, who presented with a history of GI/liver diseases and no alcohol consumption. We assessed the value of 2D-U/S technology in predicting the source of UGIB. Of 38,551 patients presenting to ED, 900 patients (2.3%), 534 male (59.3%) and 366 female (40.7%) developed UGIB. Analyzing results obtained from U/S examinations by data mining for emergent UGE were patients with liver cirrhosis (LC), splenomegaly, and ascites (42.6% incidence of UGIB), followed by LC and splenomegaly (14.6%), LC only (9.4%), and was only 0.5%who had nomorbidity finding by 2D-U/S. Ultrasonographic instrumentation increases the feasibility of predictive emergency medicine. The area has recently not only gained a fresh impulse, but also a new set of complex problems that needs to be addressed in the emergency medicine setting according to each priority. © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Ahmed R.A.,Taif University | Ahmed R.A.,Forensic Chemistry Laboratories | Fadl-Allah S.A.,Taif University | Fadl-Allah S.A.,Cairo University | And 4 more authors.
Applied Surface Science | Year: 2014

Biocomposite consists of gold nanoparticles (AuNPs) and a natural polymer as Chitosan (CS) was electrodeposited over NiTi alloy to improve biocompatibility, biostability, surface corrosion resistance and antibacterial effect for orthopedic implantation. The forming process and surface morphology of this biocomposite coats over NiTi alloy were studied. The results showed that the nm-scale gold particles were embedded in the composite forming compact, thick and smooth coat. Elemental analysis revealed significant less Ni ion release from the coated NiTi alloy compared with the uncoated one by 20 fold. Furthermore, the electrochemical corrosion measurements indicated that AuNPs/CS composite coat was effective for improving corrosion resistance in different immersion times and at all pH values, which suggests that the coated NiTi alloys have potential for orthopedic applications. Additionally, the efficiencies of the biocomposite coats for inhibiting bacterial growth indicate high antibacterial effect. © 2013 Elsevier B.V.

Fadlallah S.A.,Taif University | Fadlallah S.A.,Cairo University | El-Bagoury N.,Taif University | El-Bagoury N.,Central Metallurgical Research and Development Institute | And 5 more authors.
Journal of Alloys and Compounds | Year: 2014

Nowadays, Nickel-titanium nearly equiatomic is considered as one of the best biomaterials. The aim of the present work deals with the evolution of the electrochemical behavior of NiTi in simulated oral environment. The hardness, microstructures corrosion resistance and antibacterial performance of NiTi alloy were compared with pure titanium. The hardness of NiTi is twice the hardness of pure titanium. Electrochemical techniques were used to detect the corrosion resistance of both biomaterials in Hank's solution containing (-)-epigallocatechin gallate (EGCG) which used to simulate the oral environment. In the physiological solution selected for the present study, the impedance spectroscopy (EIS) results showed that EGCG sharply increase the corrosion resistance of NiTi from 129 kΩ cm2 to 1.10 T Ω cm 2 while slowly increase the corrosion resistance of pure titanium from 9.4 kΩ cm2 to 11.3 kΩ cm2 during the duration time of immersion at 37 C. The plate-counting method was used to evaluate the antibacterial performance against Staphylococcus aureus (ATCC 6538). Among the two specimens of biomaterials studied, the antibacterial performance results revealed that the NiTi alloy is better than the pure titanium. The morphology and chemical structure of NiTi and Ti samples were systematically investigated by scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDX). The study confirmed that the distinctive characteristics of the NiTi alloy back to its chemical composition with two phases from nickel and titanium. © 2013 Elsevier B.V. All rights reserved.

Osman A.M.G.,University of Mississippi | Abourashed E.A.,Chicago State University | Slade D.,MRI Global | Ahmed S.A.,Suez Canal University | And 8 more authors.
Medicinal Chemistry Research | Year: 2015

Ferutinin (1), the major constituent of Ferula hermonis and other Ferula species, is a sesquiterpene ester with remarkable estrogenic activity, beside other valuable medicinal properties. To investigate the influence of chemical modification of the ferutinin structure on its estrogenic effect and binding affinity toward the cannabinoid CB1 and CB2 receptors, twelve derivatives of 1 were prepared and evaluated in vitro, together with the parent compound, for the respective bioactivities, based on the recent evidence for estrogen-endocannabinoid interaction. Nine of the prepared derivatives (3-11) are new semisynthetic esters of 1. The parent compound ferutinin (1) exhibited the highest level of estrogenic activity (EC50 0.3 μM and a percent maximal 17β-estradiol response of 90 % at 1 μM). Compound 6 was found to be a selective agonist for CB2 receptor (EC50 0.051 μM, Ki 0.025 μM), with much less affinity for CB1 receptor (EC50 97 μM, Ki 48.5 μM). Compound 8 was a selective agonist for CB1 (EC50 62, Ki 0.031 μM) with no affinity toward CB2. © 2015 Springer Science+Business Media.

Gad El-Rab S.M.F.,Taif University | Gad El-Rab S.M.F.,Asuit University | Fadl-Allah S.A.,Taif University | Fadl-Allah S.A.,Cairo University | And 2 more authors.
Applied Surface Science | Year: 2012

Titanium metal (Ti) with antibacterial function was successfully developed in the present study by electrodeposition of biomimetic Ca-P coat in simple supersaturated calcium and phosphate solution (SCPS). The electrochemical behavior and corrosion resistance of Ca-P deposited on anodized titanium (AT) have been investigated in SCPS by using electrochemical impedance spectroscopy (EIS). The plate-counting method was used to evaluate the antibacterial performance against Staphylococcus aureus (ATCC6538). In vitro antibacterial activity study indicated a significantly reduced number of bacteria S. aureus on Ca-P/AT plate surface when compared with that on Ti or AT surfaces and the corresponding antibacterial mechanism is discussed. The morphology and chemical structure of different titanium samples were systematically investigated by scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDX). The study confirmed that the antibacterial properties of the samples were related to chemical composition of sample surface. © 2012 Elsevier B.V. All rights reserved.

Ali H.F.M.,Alexandria University | Bab A.M.R.F.E.,Asuit University | Zyada Z.,University of Technology Malaysia | Zyada Z.,Tanta University | Megahed S.M.,Alexandria University
2015 10th Asian Control Conference: Emerging Control Techniques for a Sustainable World, ASCC 2015 | Year: 2015

Many places in the world are contaminated with Landmines, normally buried under shallow or deep layers of sand and mud, which causes landmine detection and/or removal to be challenging tasks. To design a reliable landmine sensing system some deep analysis and many test cases are required. In this paper, existence of landmine under the ground surface is examined and its inclination angle effect on detection is analyzed applying finite element method and artificial neural networks. Inverse analyses are used to produce 'forward results'. Applying a contact pressure (lower than the expected landmine activation pressure) on the ground containing a landmine under its surface would produce a pressure distribution that is dependent on the landmine type, depth and inclination. COMSOL Multi-physics is applied to model sandy soil contaminated by two landmines of different types at different depths and surface pressure distribution is obtained applying external pressure load of 1kPa. Three NNs are trained applying the obtained surface pressure distribution data. The first NN is of perceptron type which classifies the introduced objects in sand. The other two NNs are of feed-forward NN type and are developed for estimating depths of two landmines of different types, one for each. The Landmine inclination angles (0°-30°) effect on detection rate is studied. The results are tabulated and justified. The results show that the anti-tank landmine is fully detected, while the anti-personnel landmine is only detected with a rate of 75%. It is also shown that landmine characteristics estimation is reliable when its inclination angle is small. © 2015 IEEE.

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