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Microgrid dynamic security considering high penetration of renewable energy

Protection and Control of Modern Power Systems 2018年第1期3卷 245-255页

作者： G.magdy Emad A.Mohamed G.Shabib Adel A.Elbaset Yasunori Mitani1 Department of Electrical Engineering Kyushu Institute of TechnologyTobata-KuKitakyushu-shiFukuoka 804-8550Japan Department of Electrical Engineering Faculty of Energy EngineeringAswan UniversityAswan 81528Egypt Higher Institute of Engineering and Technology King MarriottAlexandria 23713Egypt Department of Electrical Engineering Faculty of EngineeringMinia UniversityMinia 61517Egypt

This paper presents a coordination strategy of Load Frequency Control(LFC)and digital frequency protection for an islanded microgrid(MG)considering high penetration of Renewable Energy Sources(RESs).In such MGs,the reduction in system inertia due to integration of large amount of RESs causes undesirable influence on MG frequency stability,leading to weakening of the ***,sudden load events,and short circuits caused large frequency fluctuations,which threaten the system security and could lead to complete blackouts as well as damages to the system ***,maintaining the dynamic security in MGs is one of the important challenges,which considered in this paper using a specific design and various data conversion stages of a digital over/under frequency relay(OUFR).The proposed relay will cover both under and over frequency conditions in coordination with LFC operation to protect the MG against high frequency *** prove the response of the proposed coordination strategy,a small MG was investigated for the *** proposed coordination method has been tested considering load change,high integration of ***,the sensitivity analysis of the presented technique was examined by varying the penetration level of RESs and reducing the system *** results reveal the effectiveness of the proposed coordination to maintain the power system frequency stability and *** addition,the superiority of the OUFR has been approved in terms of accuracy and speed response during high disturbances.

关键词： Digital frequency relay Load frequency control(LFC) Microgrid Renewable energy sources(RESs) Dynamic

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Theory of Combined Seepage Applied to Dewatering Systems

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Journal of Water Resource and Protection 2016年第7期8卷 743-755页

作者： magdy M. Aboelela Irrigation Engineering and Hydraulics Department Faculty of Engineering Alexandria University Alexandria Egypt

In the present study, an analytical solution is presented to solve the problem of combined seepage, under a sheet piling cofferdam, applied to dewatering systems. Existence of the sheet pile creates a confined seepage followed by an unconfined seepage in the same field, which presents a combined seepage problem. Two equations were developed to analyze the combined seepage underneath a sheet piling wall. Using such equations, both the maximum height of the free surface just behind the sheet piling cofferdam (Ho) and the quantity of seepage discharge to be pumped out from the construction site (q) can be determined. The main parameters affecting the combined seepage characteristics underneath a sheet piling wall are: The depth of permeable foundation layer (T), the horizontal distance behind the sheet pile (X), the depth of excavation in the construction site (D), the embedded depth of sheet pile (S), the retained water head (H1), the accumulated seepage water depth (H2), and the side slope factor of excavation line (M). Study showed that, the above parameters have a great effect on the combined seepage, but with different extents.

关键词： Confined Seepage Unconfined Seepage Combined Seepage Sheet Piling Cofferdam Seepage Discharge Phreatic Surface

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Prevalence of social media addiction among nursing students

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Journal of Integrative Nursing 2023年第2期5卷 145-150页

作者： Marwa Mamdouh SHABAN Nagah Mahmoud ABDOU Mahmoud magdy EID Mostafa Ahmed IBRAHIM Mohammed Saad El Dean METWALY Mohamed Abdeltwab SAYED Youmna magdy Abdulwahab MANSOUR Fatma Saad RAMADAN Department of Community Health Nursing Faculty of NursingCairo UniversityCairoEgypt Department of Nursing Administration Faculty of NursingCairo UniversityCairoEgypt

Objective:The objective of this study was to assess the prevalence and level of social media addiction among nursing students in the Faculty of Nursing,Cairo *** and Methods:A descriptive cross‑sectional research design was conducted on samples of 340 students at the Faculty of Nursing,Cairo *** were collected through demographic background information sheet and Social Networking Addiction ***:All the students were addicted as 6.76%were severely addicted and 60.59%and 32.65%were moderately and mildly addicted,*** relations were found between social media addiction and students’age(χ^(2)=11.331,P=0.003),educational level(χ^(2)=20.239,P=0.003),and grade point average(χ^(2)=19.378,P=0.013).Conclusion:Internet addiction was prevalent among all students but at different levels,so early screening of students for Internet addiction using the Internet Addiction Scale is important to provide early treatment and prevent hazards to health.

关键词： Internet addiction nursing student social media

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Control of Seepage through Earth Dams Based on Pervious Foundation Using Toe Drainage Systems

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Journal of Water Resource and Protection 2016年第12期8卷 1158-1174页

作者： magdy M. Aboelela Irrigation Engineering and Hydraulics Department Faculty of Engineering Alexandria University Alexandria Egypt

Many dangerous effects arise from seepage through earth dams based on pervious layer. Therefore, the dam embankment must be provided with seepage control measures to avoid such effects. In the present work, different control methods were used such as flat slopes, toe drainage systems, and a catch drain in the tail water. The hydraulic performance of each control measure was evaluated using the analytical solutions, previously developed, to estimate the seepage quantity (q), the height of seepage surface (h3), and the coordinates of the free surface (hx). Study was conducted on a physical model for a dam embankment having a top width (b) = 10.0 meter, height (Hd) = 30.0 meter, and slope factor (m) = 1.5. The obtained results were analyzed and presented in dimensionless charts. Results showed that, the used control measures possess a great effect on the characteristics of seepage through earth dams based on pervious foundations. A comparative study was conducted between the studied toe drainage systems to enable the designers the better choice for design purposes.

关键词： Earth Dam Pervious Foundation Pipe Drainage Drainage Banquette Inclined Drainage Catch Drain Seepage Discharge

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Petrology and Geochemical Characteristic of the Younger Gabbros of Wadi Shianite Area, Southeastern Desert, Egypt

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Open Journal of Geology 2015年第8期5卷 577-588页

作者： magdy S. Basta Faculty of Petroleum and Mining Engineering Sues University Sues Egypt

The present work is a petrological study of the gabbroic rocks of wadi Shianite Southeastern Desert of Egypt. Chemical analyses for major and trace elements showed that there are 3 main gabbro types. These are: 1)?pyroxene hornblende gabbronorite;?2) hornblende gabbro;?and 3) anorthosite.?The opaque minerals study of the gabbroic rocks showed that they composed mainly of ilmenite, magnetite and sulphides. The present gabbroic rocks work are related to calc-alkaline magma type, similar to the younger gabbros in other areas in the Eastern Desert.

关键词： Pyroxene Hornblende Gabbronorite Hornblende Gabbro and Anorthosite

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China Brings Hope to Developing Countries

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Contemporary World 2022年第4期 45-48页

作者： Youssef Shawky magdy the Youth Secretariat Egyptian Communist Party

In 2022,the Communist Party of China(CPC)celebrates its 101st anniversary and will convene its 20th National *** the leadership of the CPC,China is moving closer to the center of the world *** the same time,the Arab people,especially the vast majority of the young people,are increasingly aware that neoliberalism and capitalism encounter failure in the Middle East in that they are problematic,brutally exploiting the laborers and the poor,while unable to solve major problems.

关键词： closer tally Middle

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A Thermal Shock-Chemical Reactive Problem in Flow of Viscoelastic Fluid with Thermal Relaxation

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Applied Mathematics 2012年第7期3卷 685-698页

作者： magdy A. Ezzat Wisam Khatan Department of Mathematics and Sciences Faculty of sciences and letters in Al Bukayriyyah Al-Qassim University Al-Qassim Saudi Arabia

Effects of thermal and species diffusion with one relaxation time on the boundary layer flow of a viscoelastic fluid bounded by a vertical surface in the presence of transverse magnetic field have been studied. The state space approach developed by Ezzat [1] is adopted for the solution of one-dimensional problem for any set of boundary conditions. The resulting formulation together with the Laplace transform techniques are applied to a thermal shock-chemical reactive problem. The inversion of the Laplace transforms is carried out using a numerical approach. The numerical results of dimensionless temperature, concentration, velocity, and induced magnetic and electric fields distributions are given and illustrated graphically for the problem.

关键词： MHD Heat and Mass Transfer Boundary Layer Theory Viscoelastic Fluid State Space Approach Lord-Shulman Theory Numerical Results

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Fallopian tube:Its role in infertility and gynecological oncology

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World Journal of Obstetrics and Gynecology 2014年第2期3卷 35-41页

作者： Nesreen magdy Mona El-Bahrawy Department of Pathology National Cancer Institute Cairo University Cairo 14211 Egypt Department of Histopathology Imperial College London Hammersmith Hospital London W12 0NN United Kingdom Department of Pathology Faculty of Medicine University of Alexandria Azarita 31211 Egypt

Disorders of the fallopian tube play a very important role in both infertility and gynaecological oncology. Tubal factor infertility is considered among the leading causes of female factor infertility. Many tubal disorders are related to infertility including congenital anomalies, acute and chronic inflammatory diseases, endometriosis and other pathologies that result in partial or total fallopian tube obstruction. In the field of gynaecological oncology, ovarian surface epithelial tumors remain one of the most fatal malignancies in women worldwide carrying the worst prognosis among female genital malignancies. For decades, the cell of origin of epithelial tumors has remained controversial and was largely believed to be surface ovarian epithelium. Recently several studies suggested that there is a major role of the fallopian tube in the development of ovarian surface epithelial tumors, mainly high grade serous carcinoma and other tumour types. In this article we review the role of the fallopian tube in both infertility and gynaecological oncology.

关键词： Fallopian tube Infertility Endometriosis Salpingitis Serous carcinoma

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Study on the SEIQR model and applying the epidemiological rates of COVID-19 epidemic spread in Saudi Arabia

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Infectious Disease Modelling 2021年第1期6卷 678-692页

作者： Hamdy Youssef Najat Alghamdi magdy A.Ezzat Alaa A.El-Bary Ahmed M.Shawky Mechanical Engineering Department College of Engineering and Islamic ArchitectureUmm Al-Qura UniversityMakkahSaudi Arabia Department of Mathematics Faculty of Applied ScienceUmm Al-Qura UniversityMakkahSaudi Arabia College of Science and Arts Qassim UniversityAl BukairiyahAl QassimSaudi Arabia Arab Academy for Science Technology and Maritime TransportP.O.Box 1029AlexandriaEgypt Science and Technology Unit(STU) Umm Al-Qura UniversityMakkahSaudi Arabia National Committee for Mathematics Academy of Scientific Research and TechnologyEgypt

This article attempts to establish a mathematical epidemic model for the outbreak of the new COVID-19 coronavirus.A new consideration for evaluating and controlling the COVID-19 outbreak will be constructed based on the SEIQR Pandemic *** this paper,the real data of COVID-19 spread in Saudi Arabia has been used for the mathematical model and dynamic *** the new reproductive number and detailed stability analysis,the dynamics of the proposed SEIQR model have been *** local sensitivity of the reproduction number has been *** domain of solution and equilibrium based on the SEIQR model have been proved using a Jacobian linearization *** state of equilibrium and its significance have been proved,and a study of the integrity of the disease-free equilibrium has been carried *** Lyapunov stability theorem demonstrated the global stability of the current model *** SEIQR model has been numerically validated and projected by contrasting the results from the SEIQR model with the actual COVID-19 spread data in Saudi *** result of this paper shows that the SEIQR model is a model that is effective in analyzing epidemic spread,such as *** the end of the study,we have implemented the protocol which helped the Saudi population to stop the spread of COVID-19 rapidly.

关键词： COVID-19 Jacobian matrix Lyapunov stability Reproduction number SEIR model SEIQR model

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High densities of serotonin and peptide YY cells in the colon of patients with lymphocytic colitis

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World Journal of Gastroenterology 2012年第42期18卷 6070-6075页

作者： magdy El-Salhy Doris Gundersen Jan Gunnar Hatlebakk Trygve Hausken Section for Gastroenterology Department of MedicineStord Helse-Fonna HospitalBox 40005409 StordNorway Department of Research Helse-Fonna5528 HaugesundNorway Section for Gastroenterology Institute of MedicineUniversity of Bergen5029 BergenNorway

AIM： TO investigate colonic endocrine cells in lympho- cytic colitis （LC） patients. METHODS： Fifty-seven patients with LC were in- cluded. These patients were 41 females and 16 males, with an average age of 49 years （range 19-84 years）. Twenty-seven subjects that underwent colonoscopy with biopsies were used as controls. These subjects underwent colonoscopy because of gastrointestinal bleeding or health worries, where the source of bleed- ing was identified as haemorrhoids or angiodysplasia. They were 19 females and 8 males with an average age of 49 years （range 18-67 years）. Biopsies from the right and left colon were obtained from both patients and controls during colonoscopy. Biopsies were fixed in 4% buffered paraformaldehyde, embedded in paraffin and cut into 5 μm-thick sections. The sections immunostained by the avidin-biotin-complex method for se- rotonin, peptide YY （PYY）, pancreatic polypeptide （PP） enteroglucagon and somatostatin cells. The cell densi- ties were quantified by computerised image analysis using Olympus software. RESULTS： The colon of both the patient and the control subjects were macroscopically normal. Histo- pathological examination of colon biopsies from con- trols revealed normal histology. All patients fulfilled the diagnosis criteria required for of LC： an increase in intraepithelial lymphocytes （〉 20 lymphocytes/100 epithelial cells） and surface epithelial damage with increased lamina propria plasma cells and absent or minimal crypt architectural distribution. In the colon of both patients and control subjects, serotonin-, PYY-, PP-, enteroglucagon- and somatostatin-immunoreac- tive cells were primarily located in the upper part of the crypts of Lieberk0hn. These cells were basket- or flask-shaped. There was no statistically significant dif- ference between the right and left colon in controls with regards to the densities of serotonin- and PYY- immunoreactive cells （P = 0.9 and 0.1, respectively）. Serotonin cell density in the right

关键词： Colon Computer image analysis Immuno-histochemistry Lymphocytic colitis Peptide YY Serotonin

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