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

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

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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

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Melting phenomenon in magneto hydro-dynamics steady flow and heat transfer over a moving surface in the presence of thermal radiation

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Chinese Physics B 2013年第3期22卷 57-62页

作者： Reda G.abdel-rahman M.M.Khader ahmed M.Megahed Department of Mathematics Faculty of ScienceBenha University

The Lie group method is applied to present an analysis of the magneto hydro-dynamics（MHD） steady laminar flow and the heat transfer from a warm laminar liquid flow to a melting moving surface in the presence of thermal *** using the Lie group method,we have presented the transformation groups for the problem apart from the scaling *** application of this method reduces the partial differential equations（PDEs） with their boundary conditions governing the flow and heat transfer to a system of nonlinear ordinary differential equations（ODEs） with appropriate boundary *** resulting nonlinear system of ODEs is solved numerically using the implicit finite difference method（FDM）.The local skin-friction coefficients and the local Nusselt numbers for different physical parameters are presented in a table.

关键词： Lie group method magneto hydro-dynamics melting phenomenon Newtonian fluid radiation

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Cartilage tympanoplasty in the treatment of adhesive otitis media with and without Eustachian tube balloon dilatation

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Journal of Otology 2022年第4期17卷 226-231页

作者： ahmed abdel rahman abdel aziz ahmed Mahmoud Youssef Mostafa Mohamed Mostafa Mostafa talaat Khaled Mohamed abdelzaher ahmed Adel Sadeq Department of Otorhinolaryngology Faculty of MedicineEl MiniaEgypt Radiology Department Faculty of MedicineEl MiniaEgypt

Purpose:To compare cartilage tympanoplasty(CT)combined with eustachian tube balloon dilatation(ETBD)and cartilage tympanoplasty alone as a surgical treatment modality for adhesive otitis media(AdOM)in terms of graft healing,audiological outcomes,and impact on life style,using Chronic Otitis Media Outcome Test 15(COMOT-15).Methods:50 patients with AdOM were randomly classified into 2 groups:25 patients for cartilage tympanoplasty only(CT group)and 25 patients for cartilage tympanoplasty combined with eustachian tube balloon dilatation(CT t ETBD group).Clinical outcomes in both groups were compared at 3 and 6 months of follow ***:There was no significant difference in graft healing between the two *** COMOT-15 scores significantly decreased in both groups with a significant difference between the groups with regard to the decrease in COMOT-15 scores at 3 and 6 months of follow-up(P<0.05).Hearing improvement was achieved,as the mean preoperative ABG was 26.5±5.4 and 27.1±4.6 dB,and the mean postoperative ABG at 6 months was 19.4±4.4 and 14.6±3.9 dB in the CT and the CT t ETBD groups,*** difference in the magnitude of ABG reduction in the two groups was significant at 3 and 6 months of postoperative follow-up(P<0.05)in favour of the CT t ETBD ***:ETBD can increase the success rate of cartilage tympanoplasty in patients with AdOM by enhancing the audiological outcome and quality of life.

关键词： balloon healing otitis

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Finite element modeling assumptions impact on seismic response demands of MRF-buildings

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Earthquake Engineering and Engineering Vibration 2018年第4期17卷 821-834页

作者： Shehata E abdel Raheem ahmed K abdel Zaher ahmed MA Taha Civil Engineering Department Engineering College Taibah University Civil Engineering Department Faculty of Engineering Assiut University

Recent seismic events have raised concerns over the safety and vulnerability of reinforced concrete moment resisting frame ＂RC-MRF＂ buildings. The seismic response of such buildings is greatly dependent on the computational tools used and the inherent assumptions in the modelling process. Thus, it is essential to investigate the sensitivity of the response demands to the corresponding modelling assumption. Many parameters and assumptions are justified to generate effective structural finite element（FE） models of buildings to simulate lateral behaviour and evaluate seismic design demands. As such, the present study focuses on the development of reliable FE models with various levels of refinement. The effects of the FE modelling assumptions on the seismic response demands on the design of buildings are investigated. the predictive ability of a FE model is tied to the accuracy of numerical analysis; a numerical analysis is performed for a series of symmetric buildings in active seismic zones. The results of the seismic response demands are presented in a comparative format to confirm drift and strength limits requirements. A proposed model is formulated based on a simplified modeling approach, where the most refined model is used to calibrate the simplified model.

关键词： RC-MRF buildings design codes provisions seismic design finite element modeling modeling assumptions response demands

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Seismic response of skewed RC box-girder bridges

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Earthquake Engineering and Engineering Vibration 2008年第4期7卷 415-426页

作者： ahmed abdel-Mohti Gokhan Pekcan Civil and Environmental Engineering Department University of Nevada Reno

It is critical to ensure the functionality of highway bridges after earthquakes to provide access to important facilities. Since the 1971 San Fernando earthquake, there has been a better understanding of the seismic performance of bridges. Nonetheless, there are no detailed guidelines addressing the performance of skewed highway bridges. Several parameters affect the response of skewed highway bridges under both service and seismic loads which makes their behavior complex. Therefore, there is a need for more research to study the effect of skew angle and other related factors on the performance of highway bridges. This paper examines the seismic performance of a three-span continuous concrete box girder bridge with skew angles from 0 to 60 degrees, analytically. Finite element （FE） and simplified beam-stick （BS） models of the bridge were developed using SAP2000. Different types of analysis were considered on both models such as： nonlinear static pushover, and linear and nonlinear time history analyses. A comparison was conducted between FE and BS, different skew angles, abutment support conditions, and time history and pushover analysis. It is shown that the BS model has the capability to capture the coupling due to skew and the significant modes for moderate skew angles. Boundary conditions and pushover load profile are determined to have a major effect on pushover analysis. Pushover analysis may be used to predict the maximum deformation and hinge formation adequately.

关键词： skew bridge seismic response pushover analysis time history analysis modeling

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Biochar derived from invasive plants improved the pH,macronutrient availability and biological properties better than liming for acid rain-affected soil

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Biochar 2023年第1期5卷 1029-1044页

作者： Yazheng Li ahmed I.Abdo Zhaoji Shi abdel-rahman M.A.Merwad Jiaen Zhang Department of Ecology College of Natural Resources and EnvironmentSouth China Agricultural UniversityGuangzhou 510642China Guangdong Provincial Key Laboratory of Utilization and Conservation of Food and Medicinal Resources in Northern Region Yingdong College of Biology and AgricultureShaoguan UniversityShaoguan 512005China Soil Science Department Faculty of AgricultureZagazig UniversityZagazig 44519Egypt Guangdong Laboratory for Lingnan Modern Agriculture Guangdong Provincial Key Laboratory of Eco-Circular AgricultureSouth China Agricultural UniversityGuangzhou 510642China Guangdong Engineering Technology Research Centre of Modern Eco-Agriculture and Circular Agriculture Guangzhou 510642China

Rapid development in industrialization and urbanization causes serious environmental issues,of which acid rain is one of the quintessential hazards,negatively affecting soil *** has been investigated for a long time as the most effective amendment to alter the adverse effects of soil acidity resulting from acid ***,this study tested the biochar produced from invasive plants as an alternative amendment and hypothesized that biochar can maintain better availability of macronutrients under acid rain than liming by improving soil chemical and biological ***,a pot experiment was conducted to compare the effects of lime and biochar at two rates(1%and 3%)on soil available nitrogen(N),phosphorous(P)and potassium(K)under simulated acid rain of two pH levels(4.5:pH_(4.5) and 2.5:pH_(2.5))as compared with tap water(pH7.1)as a control *** was produced using different invasive plants,including Blackjack(Biden Pilosa),Wedelia(Wedelia trilobata)and Bitter Vine(Mikania micrantha Kunth).Liming decreased the availability of soil N,P,and K by 36.3%as compared with the control due to the great increment in soil pH and exchangeable calcium(Ca^(2+))by 59%and 16-fold,***,liming reduced the alpha diversity of soil bacteria and fungi by 27%and 11%,*** contrast,biochar at different types and rates resulted in a fourfold increment in the available N,P,and K as an average under acid rain(pH_(4.5) and pH_(2.5))owing to maintaining a neutral pH(6.5-7),which is the most favorable level for soil microbial and enzymatic activites,and the bioavailability of soil ***,biochar caused balanced increments in Ca^(2+)by threefold,cation exchange capacity by 45%,urease activity by 16%,and fungal diversity by 10%,while having a slight reduction in bacterial diversity by 2.5%.Based on the path,correlation,and principal component analyses,the exchangeable aluminum was a moderator for the reductions in macronutrien

关键词： Acidic soil Liming Invasive plants Biochar feedstock Soil chemical properties

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The use of carbon nanomaterials in membrane distillation membranes:a review

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Frontiers of Chemical Science and Engineering 2021年第4期15卷 755-774页

作者： Sebastian Leaper ahmed abdel-Karim Patricia Gorgojo Department of Chemical Engineering and Analytical Science School of EngineeringThe University of ManchesterManchesterM139PLUK Water Pollution Research Department National Research CentreGiza 12622Egypt

Membrane distillation(MD)is a thermal-based separation technique with the potential to treat a wide range of water types for various applications and *** challenges remain however,which prevent it from becoming commercially widespread including moderate permeate flux,decline in separation performance over time due to pore wetting and high thermal energy ***,its attractive characteristics such as high rejection(ca.100%)of nonvolatile species,its ability to treat highly saline solutions under low operating pressures(typically atmospheric)as well as its ability to operate at low temperatures,enabling waste-heat integration,continue to drive research interests *** particular interest is the class of carbon-based nanomaterials which includes graphene and carbon nanotubes,whose wide range of properties have been exploited in an attempt to overcome the technical challenges that MD *** low dimensional materials exhibit properties such as high specific surface area,high strength,tuneable hydrophobicity,enhanced vapour transport,high thermal and electrical conductivity and *** use in MD has resulted in improved membrane performance characteristics like increased permeability and reduced fouling *** have also enabled novel membrane capabilities such as in-situ fouling detection and localised heat *** this review we provide a brief introduction to MD and describe key membrane characteristics and fabrication *** then give an account of the various uses of carbon nanomaterials for MD applications,focussing on polymeric membrane *** research directions based on the findings are also suggested.

关键词： carbon nanomaterials graphene membrane distillation desalination carbon nanotubes

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Vascular endothelial growth factor:a double-edged sword in the development of white matter lesions

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Neural Regeneration Research 2025年第1期20卷 191-192页

作者： Narek Manukjan Daniel Fulton Zubair ahmed WMatthijs Blankesteijn Sébastien Foulquier Department of Pharmacology and Toxicology Maastricht UniversityMaastrichtThe Netherlands CARIM-School for Cardiovascular Diseases Maastricht UniversityMaastrichtThe Netherlands Neuroscience and Ophthalmology Institute of Inflammation and AgeingUniversity of BirminghamEdgbastonBirminghamUK Centre for Trauma Sciences Research University of BirminghamEdgbastonBirminghamUK MHeNs-School for Mental Health and Neuroscience Maastricht UniversityMaastrichtThe Netherlands Department of Neurology Maastricht University Medical CenterMaastrichtThe Netherlands

As the population ages,the burden of age-related diseases becomes ***,over 55 million people suffer from dementia worldwide,with Alzheimer’s disease being the most common ***,it is becoming clearer that underlying vascular pathology such as cerebral small vessel disease(cSVD)may be a more detrimental cause for dementia(Cuadrado-Godia et al.,2018).It is estimated that 10%-30%of the elderly population and 35%-90%of all dementia patients exhibit signs of *** term cSVD refers to pathology affecting the small vessels of the brain,which can lead to lacunar cerebral infarcts,enlarged perivascular spaces,and cortical hemorrhages(Cuadrado-Godia et al.,2018).CSVD is often associated with cognitive decline,gait problems,and dementia(Cuadrado-Godia et al.,2018).

关键词： pathology becoming white

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Single-session minimally invasive management of common bile duct stones

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World Journal of Gastroenterology 2014年第41期20卷 15144-15152页

作者： ahmed abdel Raouf ElGeidie Gastroenterology Surgical Center Mansoura University

Up to 18% of patients submitted to cholecystectomy had concomitant common bile duct *** avoid serious complications,these stones should be *** is no consensus about the ideal management strategy for such ***,open surgery was offered but with the advent of endoscopic retrograde cholangiopancreatography(ERCP) and laparoscopic cholecystectomy(LC) minimally invasive approach had nearly replaced laparotomy because of its well-known *** invasive approach could be done in either twosession(preoperative ERCP followed by LC or LC followed by postoperative ERCP) or single-session(laparoscopic common bile duct exploration or LC with intraoperative ERCP).Most recent studies have found that both options are equivalent regarding safety and efficacy but the singlesession approach is associated with shorter hospital stay,fewer procedures per patient,and less ***,single-session option should be offered to patients with cholecysto-choledocholithiaisis provided that local resources and expertise do ***,the management strategy should be tailored according to many variables,such as available resources,experience,patient characteristics,clinical presentations,and surgical pathology.

关键词： Laparoscopic exploration Endoscopic retrograde cholangiopancreatography Common bile duct stones Minimally invasive approach Single-session

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