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Experimental and Numerical Investigation of the Solar Chimney Power Plant’s Turbine

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Open Journal of Fluid Dynamics 2016年第4期6卷 332-342页

作者： Magdy Bassily Hanna tarek abdel-malak mekhail Omar Mohamed Dahab Mohamed Fathy Cidek Esmail Ahmed Rekaby abdel-Rahman Faculty of Engineering Mechanical Power and Energy Department Minia University Minia Egypt Faculty of Energy Engineering Mechanical Power Department Aswan University Aswan Egypt Faculty of Engineering Mechanical Power Department Aswan University Aswan Egypt

The solar chimney power plant is a relatively new electricity generation concept, based on renewable energy, combining the greenhouse effect with the chimney suction. The solar chimney powerplant consists of three parts, the solar collector, the chimney and the turbine generator unit, of which the study was focused on the later part. To evaluate the turbine performance inside the solar chimney powerplant, experimental system was constructed in Aswan, Egypt that has a metrological site (23°58'N and 32°47'E) occurs. The system was constructed to evaluate the performance of the solar chimney turbine and power generation characteristic in the hottest site where Aswan is located at the nearest of the Tropic of Cancer at the summer season. Velocity, electric power generation and the turbine efficiency are studying in this work. The numerical analyses were performed by using a commercial code CFX, ANSYS 16.1 to simulate the flow through the turbine and overall system. The study shows that the range of power generated (1.2 W - 4.4 W). It can be estimated, according to the results, the variation trend in pressure drops with the turbine rotation speed increase with small differences when the turbine rotation speed surpasses 1800 rpm with average efficiency of 57%. It is concluded that the theoretical model is basically valid for the system under study, and the CFD simulation can be used conveniently to predict the performance of the system, the comparison between them and experimental result shows a good agreement.

关键词： Solar Chimney Natural Convection Turbine Modeling CFD

Performance Investigation of the Solar Chimney Power Plants Heater Case Study in Aswan, Egypt

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Journal of Power and Energy Engineering 2016年第10期4卷 39-60页

作者： Magdy Bassily Hanna tarek abdel-malak mekhail Omar Mohamed Dahab Mohamed Fathy Cidek Esmail Ahmed Rekaby abdel-Rahman Mechanical Power and Energy Department Faculty of Engineering Minia University Minia Egypt Mechanical Power Department Faculty of Energy Engineering Aswan University Aswan Egypt Mechanical Power Department Faculty of Engineering Aswan University Aswan Egypt

Solar collector is a thermal device that uses the heated air in the power generation and many engineering applications. The purpose of the present work is to study the performance and temperature distribution for the solar collector which uses heated air in solar chimney power generation that it consist of three parts, a turbine-generator unit which is used in the generation of electric energy, and cylindrical chimney is fixed vertically and finally a solar collector under the climatic conditions of Egypt-Aswan is studied. This site is specified as the hottest site because the nearest of this location from the Tropic of cancer. Experiments are performed in ten summer days of May and June 2015 with different solar radiations and clarity of the sky. Hourly values of global solar radiation and some meteorological data (temperature, pressure, velocity, etc.) for measuring days are obtained by measuring devices. Inlet and outlet temperatures of air from a solar collector and velocity at junction region. In this work, attempt has been made to present the effect of environmental factors such as ambient temperature, the clarity of the sky and solar radiation on the performance of solar collector. The temperature of the base and the cover of the solar collector, the variation of solar radiation, solar collector efficiency, heat transfer coefficient, the velocity at the junction region between the chimney base, the outlet of the solar collector and temperature distribution along the air heater are discussed. A prediction for the results of the solar collector were performed by using developed theoretical model was made by this study which is based on the previous works. The numerical study has used a commercial code CFX, ANSYS 16.1 to simulate the flow through the collector. The study show that the outlet air temperatures from the solar collector and the velocity at the junction are depending on the climate condition such as ambient temperature and solar radiation, the differ

关键词： Solar Chimney Solar Collector Natural Convection Computational Fluid Dynamic

Theoretical, Experimental and Numerical Investigations of the Effect of Inlet Blade Angle on the Performance of Regenerative Blowers

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Open Journal of Fluid Dynamics 2015年第3期5卷 224-237页

作者： tarek abdel-malak mekhail Omar Mohamed Dahab Mohamed Fathy Sadik Mahmoud Mohamed El-Gendi Hesham Sayed abdel-Mohsen Faculty of Energy Engineering Mechanical Power Department Aswan University Aswan Egypt Faculty of Engineering Mechanical Power Department Aswan University Aswan Egypt Faculty of Engineering Mechanical Power and Energy Department Minia University Minia Egypt

Regenerative machines allow high heads at small flow rates and present performance curves with very stable features. This research includes a study of the effect of four inlet flow angles (90°, 115°, 125° and 135°) of the blade at outlet flow angle of 90° on the performance of regenerative blower at rotation speed of 3000 rpm and at different flow rates. Investigation and comparison of the experimental results with both one-dimensional theoretical model and numerical CFD technique using CFX-ANSYS 16.1 are done. The numerical CFD analysis show that the flow enters the impeller from the blade side (about 65% of the blade side area) and leaves from the blade tip and blade side (the remaining 35% from the blade side area). According to this observation, a mathematical model that is based on momentum exchange theory to handle one inlet angle and two exit angles for the regenerative blower impeller blades is proposed. Consequently, the experimental work is carried out by two steps. The first step is done by studying the effect of inlet blade angle of 90° and analyzing the results by using the CFD analysis. The CFD results show shock losses and vortices behind each blade at the inlet flow regions. To reduce these losses, an increase of the inlet blade angle in a range between 25° to 45° is proposed. The second step is the splitting of this angle range to three inlet blade angles of 115°, 125° and 135° in order to study and analyze the CFD results for these angels. The CFD analysis shows the disappearance of the shock losses and vortices that are formed behind the blade of angle 90°. The experimental results show that the pressure head and the efficiency depend strongly on the blade inlet and outlet flow angles as well as on the blade geometry. The results also show that the best blower performance can be obtained at an inlet flow angle of 125°, and this is confirmed by CFD simulation analysis. Finally, it is shown that the proposed one-dimensional model yield results that

关键词： Regenerative Blower Circulatory Flow CFD Shock Losses Vortices Impeller Angles

Nanoscale electropolishing of high-purity nickel with an ionic liquid

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International Journal of Minerals,Metallurgy and Materials 2019年第5期26卷 649-656页

作者： Jon Derek Loftis tarek M.abdel-Fattah Applied Research Center at Thomas Jefferson National Accelerator Facility and Department of Molecular Biology and Chemistry at Christopher Newport University Department of Physical Sciences Virginia Institute of Marine Science College of William and Mary Faculty of Sciences Alexandria University

High purity(>99.9% composition) nickel metal specimens were used in electropolishing treatments with an acid-free ionic liquid electrolyte prepared from quaternary ammonium salts as a green polishing solution. Voltammetry and chronoamperometry tests were conducted to determine the optimum conditions for electrochemical polishing. Atomic force microscopy(AFM) revealed nanoscale effectiveness of each polishing treatment. Atomic force microscopy provided an overall observation of the material interface between the treated and unpolished regions. Surface morphology comparisons summarized electrochemical polishing efficiency by providing root-mean-square roughness averages before and after electrochemical polishing to reveal a mirror finish six times smoother than the same nickel metal surface prior to electropolishing. This transition manifested in a marked change in root-mean-squared roughness from 112.58 nm to 18.64 nm and producing a smooth mirror finish. Finally, the mechanism of the ionic liquid during electropolishing revealed decomposition of choline in the form of a transient choline radical by acceptance of an electron from the nickel-working electrode to decompose to trimethylamine and ethanol.

关键词： electrochemical polishing ionic liquid Ni 2EG:1VB4

Mean Platelet Volume and Prognosis of Unstable Angina

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World Journal of Cardiovascular Diseases 2015年第2期5卷 32-41页

作者： tarek M. abdel-Rahman Cardiology Department El Minia University Hospital Minya Egypt

Objective: Clopidogrel therapy is the standard of care in patients with unstable angina. However, a percentage of subjects are nonresponders to clopidogrel and this leads to increased adverse outcome. On the other way round, some responsive patients are exposed to bleeding complications. Detection of both in daily practice is important in order to tailor the treatment protocol. In this study we aimed to estimate the cutoff value of mean platelet volume (MPV) for both platelet responsiveness and bleeding risks. Methods: The study was planned as a prospective cohort study. A total number of 230 patients admitted to our CCU with unstable angina over a period of one year (from June 2013 to May 2014) were enrolled. Exclusion criteria were: severe anemia, throm-bocytopenia, myelodysplastic syndrome, coagulopathy and recent blood transfusion. In all patients clopidogrel was initially started and maintained during the hospital stay. Blood (2 ml) was collected in dipotassium EDTA tubes from all patients on the first day of admission by a clean puncture. Samples for MPV analysis were drawn on admission, and analyzed within 1 hour of admission after sampling by Beckman Caulter LH 780 Analyzer. Grouping was then done according to MPV of the patients into group (I) who had a low MPV less than or equal to 7.00 fl, and group (II) with MPV equal to or higher than 9.00 fl. Demographical and clinical variables of the patients were recorded. Routine laboratory parameters were also recorded. Clinical manifestations during the admission period were meticulously reported. Major complications as bleeding or, urgent need for percutaneous coronary intervention (PCI) were also studied. Results: Among the 230 patients analyzed, 175 patients (76%) were found to have MPV ≤7.00 fl (group (I)) and 55 patients (24%) had MPV ≥9.00 fl (group (II)) with mean ± SD MPV (8.4 ± 1.5 fl, vs 11.7 ± 1.2 fl respectively) (p < 0.001). Observation of clinical course during admission period revealed a statistica

关键词： Clopidogrel Resistance Unstable Angina Mean Platelet Volume

Value of Orthostatic Hypotension as a Prognostic Bed-Side Test in Heart Failure

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World Journal of Cardiovascular Surgery 2012年第4期2卷 132-140页

作者： tarek M. abdel Rahman Cardiology Department El Minia University Hospital Minya Egypt

Background: Neurohumoral compensatory mechanisms play an important role in stabilizing the functional activity of patients with heart failure using the arms of autonomic nervous system. Orthostatic Hypotension (OH) is one of the most incapacitating symptoms of Cardiac Autonomic Dysfunction (CAD). OH can include sympathetic withdrawal which in turn leads to marked disability and deterioration of heart failure symptoms. Progressive Autonomic Dysfunction (AD) associated with progressive deterioration and impact on mortality of many diseases as hypertension, diabetes and other chronic diseases. The idea of using (OH) as a bed-side simple test expecting the risk of deterioration of cardiac function and furthermore on mortality open a gateway for preventive medicine and care to these group of patients. For more confidential prove, studying subjective and objective factors in heart failure patients became necessary to support these idea. Methods and Results: Sixty-Four patients with known history of heart failure were collected. All patients taking the fixed regiment of 4 drugs (diuretic, ACE inhibitor, Digitalis and B-blocker) in appropriate tolerated doses for two weeks prior to the study. History taking and all routine investigations were done for all patients. Grouping is based upon wither they have (OH) or not. Group-A found to have normal Bp response to standing;they were 24 patients (18 male and 6 female) of mean Age (45 ± 8 years). Group-B discovered to have significant (OH) and was 22 patients (16 males and 6 females) of mean Age (43 ± 4 years). The first Clinical and Echocardiographic examination was done and considered as a base-line characteristic. Then, a Call-back after 6 months for follow-up and second visit examination is recorded. Furthermore, every patient was advised to report changes in his clinical symptoms in a note-book describing five main items to answer a questionnaire at the end of the study involves [times of admission to hospital, need for trea

关键词： Orthostatic Hypotension Heart Failure

Mobile Based IoT Solution for Helping Visual Impairment Users

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Advances in Internet of Things 2021年第4期11卷 141-152页

作者： Hussein abdel-Jaber Hussein Albazar Ahmed abdel-Wahab malak El Amir Areej Alqahtani Mohammed Alobaid Faculty of Computer Studies Arab Open University Riyadh Saudi Arabia Systems and Computers Engineering Faculty of Engineering Al-Azhar University Cairo Egypt

Blind people have many tasks to do in their lives. However, blindness generates challenges for them to perform their tasks. Many blind persons use a traditional stick to move around and to perform their tasks. But the obstacles are not detected in traditional stick, it is ineffective for visually impaired people. The blind person has no idea what kind of objects or obstacles are in front of him/her. The blind person has no idea what size the object is or how far away he or she is from it. It is difficult for a blind person to get around. To assist people with vision impairment by making many of their daily tasks simple, comfortable, and organized, they will be able to recognize anything (an obstacle for blind people). A smart stick with mobile application can be used. One of the solutions is a mobile-based Internet of Things solution, which is a stick intended to assist visually impaired people to navigate more easily. It enables blindness and low vision people to navigate and carry out their daily tasks with ease and comfort. A technologically advanced blind stick that enables visually impaired people to move with ease. This paper proposes a system of software and hardware that helps visually impairment people to find their ways in an easy and comfortable way. The proposed system uses smart stick and mobile application to help blind and visually impaired people to identify objects (such as walls, tables, vehicles, people, etc.) in their ways, this can enable them to avoid these objects. In addition, as a result, the system will notify the user through sound from the smartphone. Finally, if he/she gets lost, he will be able to send an SMS with his/her GPS location.

关键词： IoT Ultrasonic Sensor Obstacle Detection GPS Smart Stick Arduino

Robotics explorations to enhance information technology literacy in rural schools

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通讯和计算机（中英文版） 2009年第3期6卷 55-63页

作者： tarek abdel-Salam Nehad El Sawaf Keith Williamson East Carolina University USA Helwan University Egypt Virginia State University USA

Signs of Phase Transition in High Energy Proton-Proton Collisions

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Journal of Applied Mathematics and Physics 2022年第6期10卷 1887-1897页

作者： Mohamed tarek Hussein Mohamed Tawfik Ghoneim Zeinab abdel-Halim Faculty of Science Cairo University Cairo Egypt

The present work aims to study the possible states of matter and the location of phase boundaries between hadronic gas and the quark-gluon plasma QGP. The boundary at the hadron freeze-out is also considered. Proton-proton collisions at a wide range of center of mass energies are used to examine the phase transition (entropy-temperature) diagram. Local thermodynamic equilibrium is assumed at different intervals of rapidity space. The entropy of the system is expressed in terms of the multiplicity of hadron production in each interval. However, the local temperature is estimated using the average transverse momentum. The values of the critical temperatures are found at the boundaries of the phases with a quite clear description of the states.

关键词： Proton-Proton Collision Quark-Gluon Plasma (QGP) Phase Transition Quantum Chromo Dynamics (QCD)