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Numerical Investigations of Flow Pattern and Anti-Vortex Measures of the Pumping Station Forebay

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Numerical Investigations of Flow Pattern and Anti-Vortex Mea...

作者： Ahmed Nasr elsayed Ali Nasr Farhan 扬州大学

学位级别：硕士

泵站前池是外河和进水池（进水流道）的连接段,其作用是为了保证水流在从外河流向进水池（进水流道）的过程中能够平顺地扩散,为进水池（进水流道）提供良好的流态。依据水流方向,前池可分为正向进水前池和侧向进水前池两种基本类型,侧... 详细信息

泵站前池是外河和进水池（进水流道）的连接段,其作用是为了保证水流在从外河流向进水池（进水流道）的过程中能够平顺地扩散,为进水池（进水流道）提供良好的流态。依据水流方向,前池可分为正向进水前池和侧向进水前池两种基本类型,侧向进水前池拥有占的地方少、投资省等各种特点,在中国的农业灌溉、火电厂循环供水及城战给水排水泵站中较为常见,若泵站兴建所处地形条件狭窄、正向进水不容易布置的情况下常采用侧向进水前池,此时侧向进水前池的水流与进水池（进水流道）水流方向正交或斜交,因流向的改变,前池内易形成回流或旋涡,流速分布变得不均匀,流态紊乱,造成进水池（进水流道）入口处流速分布不均匀,将会导致泵装置水力效率从而降低,影响泵装置中安全稳定的运行,并缩短水泵的使用寿命。本论文以江苏省徐州市翟山大沟泵站为本次的研究对象,该泵站的前池为典型的侧向进水结构且前池具有较大纵向底坡,为明确该泵站侧向进水前池的流场分布特征并且能够确保机组安全稳定的运行,本文将使用数值模拟技术的方法对该泵站的侧向进水前池内流场进行数值模拟,通过定性和定量相结合的分析方法揭示前池的流场特征并对前池流态调控措施的流场调控效果进行对比和分析,优选整流措施,为实际工程提供技术支撑,也为同类型泵站的前池流态调控提供参考。目前,国内外一些学者针对泵站前池的流场及流态调控措施的研究展开了不少的研究工作,研究方法主要集中于数值模拟和物理模型试验。随着实际泵站工程规模越来越大且复杂,物理模型试验的研究方式越来越不经济,且具有耗时长、人力受限和所需场地大等诸多困难而在前池流场及流态调控研究中应用的较少,随着CFD（Computational Fluid Dynamic）技术的不断发展和成熟。通过中国知网以及其他等数据库的文献查询,采用数值模拟技术研究前池流场的论文占比89.33%,CFD数值模拟技术具有省时、省工及研究成本低的优点在前池流场及流态调控中的应用也变得越来越多,很多学者采用CFD数值模拟技术模拟实际泵站工程的运行以得出问题并分析解决,通过数值模拟结果提出了流态调控措施解决实际泵站前池中的流态问题,对实际工程的前池流场做出改善,同时和物理模型试验相比,CFD数值模拟技术可模拟更大范围的泵站建筑物并更快捷、更经济地获得结论,本文对泵站前池流场及流态调控措施的研究采用数值模拟技术。翟山大沟泵站主要承担暴雨季排除多余的降水,在旱季为了能够保证农作物的正常需水,属于农业灌排泵站。泵站有四个进水池,每个进水池都装有潜水轴流泵装置单机设计流量为4.25 m3/s,泵站总设计流量为17 m3/s,每台泵之间的间距为4.4 m,进水池的长度为9.8m。引河的研究尺寸为:长83.3m,宽11.2m。该泵站受限于实际地形条件布置,前池通过两个斜坡与进水池相连接,第一级斜坡高差为1.1 m,第二级斜坡高差为4.9 m。（一）研究内容及技术路线（1）采用数值模拟技术分析翟山大沟泵站的侧向进水前池的流场分布特征;（2）针对该侧向进水前池的流态特征,提出不同的整流措施并开展数值计算;（3）采用定量和定性相结合的方法对比分析各整流措施方案与初设方案的前池流场的差异性,选优合适的整流方案。本文采用Solidworks三维建模软件对翟山大沟泵站引河、前池、进水池和潜水泵进行流体域的整体三维建模,通过网格数量无关性和网格收敛性确定数值计算网格数量从而确保数值计算的有效性,在分析初设方案前池流场特征的基础上提出若干侧向进水前池的整流措施,并通过定量和定性相结合的方法对比分析各整流措施方案,最终优选合适的整流措施,本文所研究的技术路线如图1所示:图1技术路线图（二）数值计算方法基于对三维不可压缩流体的雷诺时均N-S方程和RNG k-ε湍流模型,RNG k-ε湍流模型计算式如式（1）所示,壁面函数采用可伸缩壁面函数处理近壁区流动,采用ANSYSCFX软件对翟山大沟泵站的引河、前池、进水池和潜水泵的流场进行整体数值求解。非结构化网格拥有着很强的自适应几何形体的优点,则引河、前池、进水池和潜水泵均使用非结构化网格剖分,针对流场分析的重点关注区域进行了局部网格加密处理。计算模型的进口边界条件设置为流量,出口边界条件设置为压力,固体壁面采用无滑移壁面处理,引河的平均粗糙度设置为2.5 mm,前池和进水池的壁面粗糙度设置为2 mm。引河、前池和进水池的表面为自由液面,忽略空气对水面产生的切应力和热交换采用对称平面条件,各相连过流建筑物的交界面均采用静静交界面。泵站前池数值计算各物理量的残差收敛精度设置为1×10-6。RANS可以如下进行:（1）k方程可以表示为:（2）ε方程可以定义为:（3）ε方程可以从RANS方程得到。涡流粘度为:μt=ρCμk2/ε（4）常数σκ,σε,C1,C2,＆Cμ是根据软件ANSYS-CFX中基于实验数据在5%

关键词：泵站前池流态数值模拟整流侧向进水

Modification of Serum Galectin-3 and Reversal of Cardiac Remodeling Following Pediatric Transcatheter Atrial Septal Defect Closure

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Congenital Heart Disease 2022年第2期17卷 173-185页

作者： Omnia Shafei Alyaa A.Kotby Mona MEl Ganzoury Nevin M.Habeeb Eman elsayed Department of Pediatrics Faculty of MedicineAin Shams UniversityCairoEgypt Children’s Hospital Cardiology UnitAin Shams University HospitalsCairoEgypt

Objectives:We aimed to evaluate the effect of percutaneous atrial septal defect(ASD)closure in children using right heart indices and serum galectin-3(Gal-3),as potential biomarkers of right heart ***:This case–control prospective study included 40 children with ASD and 25 control *** echocardiographic evaluation was performed before the procedure,as well as 24 h,1 month,and 6 months after *** Gal-3 was measured before,and 1 month after the ***:Serum Gal-3 concentration,right atrial(RA)dimensions,right ventricular(RV)dimensions,indexed RA area,and right index of myocardial performance(RIMP)were significantly increased in children with ASD compared with control subjects while tricuspid annular plane systolic excursion(TAPSE)was significantly *** months after closure,RA,and RV dimensions significantly decreased and RVfunction improved(RIMP decreased and TAPSE increased).Gal-3 oncentration significantly decreased 1 month after ASD closure,but it did not reach normal range compared with control subjects.A positive correlation between Gal-3 and age at closure,RA area,RV dimensions,and RIMP was observed.A positive correlation was observed between the decrease in Gal-3 concentration and the decrease in RA area and RV dimensions 1 month after ASD closure.A significant negative correlation was observed between TAPSE and Gal-3 concentration before and after ***:Percutaneous ASD closure can improve right-sided indices and decrease serum Gal-3 ***-3 can be used as a sensitive biomarker of right heart remodeling,with a decrease in Gal-3 concentration suggesting reversal of maladaptive remodeling.

关键词： Percutaneous device closure Galectin-3 cardiac remodeling children atrial septal defect

Development of Social Media Analytics System for Emergency Event Detection and Crisis Management

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Computers, Materials & Continua 2021年第9期68卷 3079-3100页

作者： Shaheen Khatoon Majed AAlshamari Amna Asif Md Maruf Hasan Sherif Abdou Khaled Mostafa elsayed Mohsen Rashwan Department of Information System College of Computer Science and Information TechnologyKing Faisal UniversityAl-Ahsa31982Saudi Arabia Faculty of Computers and Artificial Intelligence Cairo UniversityEgypt Faculty of Computing&Information Cairo UniversityEgypt Faculty of Engineering Cairo UniversityEgypt

Social media platforms have proven to be effective for information gathering during emergency events caused by natural or human-made *** response authorities,law enforcement agencies,and the public can use this information to gain situational awareness and improve disaster *** case of emergencies,rapid responses are needed to address victims’requests for *** research community has developed many social media platforms and used them effectively for emergency response and coordination in the ***,most of the present deployments of platforms in crisis management are not automated,and their operational success largely depends on experts who analyze the information manually and coordinate with relevant humanitarian agencies or law enforcement authorities to initiate emergency response *** seamless integration of automatically identifying types of urgent needs from millions of posts and delivery of relevant information to the appropriate agency for timely response has become *** research project aims to develop a generalized Information Technology(IT)solution for emergency response and disaster management by integrating social media data as its core *** this paper,we focused on text analysis techniques which can help the emergency response authorities to filter through the sheer amount of information gathered automatically for supporting their relief *** specifically,we applied state-of-the-art Natural Language Processing(NLP),Machine Learning(ML),and Deep Learning(DL)techniques ranging from unsupervised to supervised learning for an in-depth analysis of social media data for the purpose of extracting real-time information on a critical event to facilitate emergency response in a *** a proof of concept,a case study on the COVID-19 pandemic on the data collected from Twitter is presented,providing evidence that the scientific and operational goals have been achieved.

关键词： Crisis management social media analytics machine learning natural language processing deep learning

The Solutions and the Dynamic Behavior of the Rational Difference Equations

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Journal of Applied Mathematics and Physics 2023年第2期11卷 525-540页

作者： Nisreen A. Bukhary elsayed M. elsayed Mathematics Department Faculty of Science King Abdulaziz University Jeddah KSA Faculty of Science Mathematics Department Majmaah University Al Majma’ah Riyadh KSA Faculty of Science Mathematics Department Mansoura University Mansoura Egypt

The main purpose of this paper is to study the dynamic behavior of the rational difference equation of the fourth order Where α, β and γ are positive constants and the initial conditions y-3, y-2, y-1, y0 are arbitrary positive real numbers. Also, we obtain the solution of some special cases of this equation and investigate the existence of a periodic solutions of these equations. Finally, some numerical examples will be given to explicate our results. .

关键词： Difference Equation Local Stability Global Attractor Boundedness Periodic

Sequential Observation and Control of Robotic Systems Subjected to Measurement Delay and Disturbance

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Intelligent Control and Automation 2012年第4期3卷 291-302页

作者： elsayed ElBeheiry Department of Production Engineering and Mechanical Design Faculty of Engineering Menoufiya Unicersity Minoufia Egypt

An approach for motion control and observation of robotic manipulators is presented in this article. It links the design of a joint acceleration controller to the design of a variable structure observer including Luenberger-like observation term. Both the joint acceleration controller and the observer that are introduced in this paper are very likely to use either large or moderate or small gains. Thus the time delay issue of the output measurements is highly taken into consideration in the design of the intended observers. The observer design is therefore based on two different generalized forms of nonlinear systems with/without undelayed outputs. A study to investigate the effects of the gains of the joint acceleration controller on the performance capabilities of the observer is introduced. Also, the effects of the time delay factor on the operation of both the controller and the observer and their own interaction are studied. Then a chain observer design is presented for circumventing the time delay effects. The time delay constant is found to be of vital importance to the robot performance capabilities. Moreover, the results show that the gains of the joint acceleration controller are of significant influence on the operation of the proposed observers.

关键词： Nonlinear Observers Robotic Manipulators Time Delay Joint Acceleration Control

Minimizing Buoyancy Factor of Metallic Pressure-Hull Subjected to Hydrostatic Pressure

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Intelligent Automation & Soft Computing 2023年第1期35卷 769-793页

作者： Mahmoud Helal elsayed Fathallah Abdulaziz H Alghtani Hussein Shawki Osman Jong Wan Hu Hasan Eleashy Department of Mechanical Engineering Faculty of EngineeringTaif UniversityTaif 21944Saudi Arabia Production and Mechanical Design Department Faculty of EngineeringMansoura UniversityMansoura 35516Egypt Civil Engineering Department M.T.C.Kobry ElkobbaCairo 11865Egypt Ships and Submarines Engineering Department Military Technical CollegeCairo 11865Egypt Civil Engineering Department Sohag UniversitySohag 82524Egypt Department of Civil and Environmental Engineering Incheon National UniversityIncheon 22012Korea Incheon Disaster Prevention Research Center Incheon National UniversityIncheon 22012Korea Mechanical Engineering Department Faculty of Engineering&TechnologyFuture University in EgyptCairo 11835Egypt

To increase the payload,reduce energy consumption,improve work efficiency and therefore must accordingly reduce the total hull weight of the *** paper introduces a design optimization process for the pressurehull of submarines under uniform external hydrostatic pressure using bothfinite element analysis(FEA)and optimization tools.A comprehensive study about the optimum design of the pressure hull,to minimize the weight and increase the volume,to reach minimum buoyancy factor and maximum operating depth minimizing the buoyancy factor(B.F)is taken as an objective function with constraints of plate and frame yielding,general instability and *** optimization process contains many design variables such as pressure-hull plate thickness,unsupported spacing,dimensions of long and ring beams andfinally the elliptical submersible pressure-hull *** optimization process was conducted using ANSYS parametric design language(APDL)and *** Multi-Island Genetic Algorithm(G.A)is considered to conduct the optimization ***,parametric analysis is done on the pressure hull to examine the effect of different design variables on the pressure-hull *** a result,the B.F of the proposed optimal model is reduced by an average of 31.78%compared with Reference Model(RM).Maximum von Mises stress is reduced by 27%as *** results can be helpful for submarine pressure-hull designers.

关键词： Buoyancy factor pressure-hull material failure ANSYS ISIGHT general instability

Extension of Direct Citation Model Using In-Text Citations

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Computers, Materials & Continua 2021年第3期66卷 3121-3138页

作者： Abdul Shahid Muhammad Tanvir Afzal Muhammad Qaiser Saleem M.S.elsayed Idrees Majzoob K.Omer Institute of Computing Kohat University of Science and TechnologyKohat26000Pakistan Department of Computer Science NAMAL InstituteMianwali42250Pakistan College of Computer Science and Information Technology Albaha UniversityAl BahaSaudi Arabia

Citations based relevant research paper recommendations can be generated primarily with the assistance of three citation models:(1)Bibliographic Coupling,(2)Co-Citation,and(3)Direct *** of new scholarly articles are published every *** flux of scientific information has made it a challenging task to devise techniques that could help researchers to find the most relevant research papers for the paper at *** this study,we have deployed an in-text citation analysis that extends the Direct Citation Model to discover the nature of the relationship degree-ofrelevancy among scientific *** this purpose,the relationship between citing and cited articles is categorized into three categories:weak,medium,and *** an experiment,around 5,000 research papers were crawled from the *** research papers were parsed for the identification of in-text citation ***,0.1 million references of those articles were extracted,and their in-text citation frequencies were computed.A comprehensive benchmark dataset was established based on the user ***,the results were validated with the help of Least Square Approximation by Quadratic Polynomial *** was found that degreeof-relevancy between scientific papers is a quadratic increasing/decreasing polynomial with respect to-increase/decrease in the in-text citation frequencies of a cited ***,the results of the proposed model were compared with state-of-the-art techniques by utilizing a well-known measure,known as the normalized Discount Cumulative Gain(nDCG).The proposed method received an nDCG score of 0.89,whereas the state-of-the-art models such as the Content,Bibliographic-coupling,and Metadata-based Models were able to acquire the nDCG values of 0.65,0.54,and 0.51 *** results indicate that the proposed mechanism may be applied in future information retrieval systems for better results.

关键词： Direct citation model in-text citations frequencies normalized discount cumulative gain least square approximation

Stochastic Analysis of Low-Cost Single-Frequency GPS Receivers

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Positioning 2016年第3期7卷 91-100页

作者： mohamed elsayed Elsobeiey Department of Hydrographic Surveying Faculty of Maritime Studies King Abdulaziz University Jeddah Kingdom of Saudi Arabia

Typically, dual-frequency geodetic grade GNSS receivers are utilized for positioning applications that require high accuracy. Single-frequency high grade receivers can be used to minimize the expenses of such dual-frequency receivers. However, user has to consider the resultant positioning accuracy. Since the evolution of low-cost single-frequency (LCSF) receivers is typically cheaper than single-frequency high grade receivers, it is possible to obtain comparable positioning accuracy if the corresponding observables are accurately modelled. In this paper, two LCSF GPS receivers are used to form short baseline. Raw GPS measurements are recorded for several consecutive days. The collected data are used to develop the stochastic model of GPS observables from such receivers. Different functions are tested to determine the best fitting model which is found to be 3 parameters exponential decay function. The new developed model is used to process different data sets and the results are compared against the traditional model. Both results from the newly developed and the traditional models are compared with the reference solution obtained from dual-frequency receiver. It is shown that the newly developed model improves the root-mean-square of the estimated horizontal coordinates by about 10% and improves the root-mean-square of the up component by about 39%.

关键词： Single-Frequency Receiver Stochastic Analysis Precise Point Positioning

Prevalence of intestinal parasitic infections and its relationship with socio-demographics and hygienic habits among male primary schoolchildren in Al-Ahsa,Saudi Arabia

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Asian Pacific Journal of Tropical Medicine 2010年第11期3卷 906-912页

作者： Hamdan Ibrahim Al-mohammed Tarek Tawfik Amin elsayed Aboulmagd Hatem Refaat Hablus Burhan Omar Zaza Department of Medical Microbiology and Parasitology College of MedicineKing Faisal UniversitySaudi Arabia Department of Community Medicine Faculty of MedicineCairo UniversityEgypt Department of Paediatrics College of MedicineKing Faisal UniversitySaudi Arabia Technical Director School Health Preventive ServicesMinistry of EducationAl-Hofuf DirectorateSaudi Arabia

Objective:To investigate the prevalence of different intestinal parasitic infections among male primary schoolchildren in Al-Ahsa,Saudi Arabia,and to explore the possible relative socioeconomic, environmental and behavioural sanitary ***:A cross-sectional descriptive study was performed.A total of 1 289 male students aged from 7 to 12 years were selected randomly from 20 urban and 12 rural primary schools by multistage sampling method. Data collection was carried out by self administered questionnaire form to the parents/guardians of students and included inquires about socio-demographics,environmental conditions,and behavioural sanitary *** analysis was carried out to examine the presence of intestinal parasitic ***:Overall prevalence of parasitic infections was 27.2%,more among rural *** encountered infections included Entamoeba histolytica/dispar(8.2%), Giardia lamblia(6.5%),Entamoeba coli(4.0%) and Enterobius vermicularis(1.6%).Logistic regression revealed that lower maternal educational level and occupational status,low family income,big family size,poor personal hygienic practices and positive history of previous intestinal infections among family members increased the likelihood of ***: Although of low magnitude,intestinal parasitic infections still represent a public health concern among male schoolchildren in Al-Ahsa ***-demographic and poor personal hygienic habits are the main predictors for these infections.

关键词： Intestinal parasitic infections Schoolchildren Epidemiological correlates Hygiene Saudi Arabia