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Effect of Aging on the Toughness of Austenitic and Duplex Stainless Steel Weldments

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Journal of Materials Science & Technology 2010年第9期26卷 810-816页

作者： Omyma Hassan ibrahim ibrahim Soliman ibrahim Tarek ahmed Fouad Khalifa Metallurgy Dept. Nuclear Research CentreAtomic Energy Authority(Egypt) Nuclear Safety Centre Atomic Energy Authority(Egypt) Shoubra Faculty of Engineering Benha University

In the present study,the effect of aging heat treatment at 650,750,and 850？C on the impact toughness of 316L austenitic stainless steel,2205 duplex stainless steel and their weldments has been *** process was conducted using the TIG（tungsten inert gas） welding *** impact testing,at room temperature,was employed to determine the effect of aging treatment on the impact properties of investigated *** treatment resulted in degradation in the impact toughness as demonstrated by the reduction in the impact fracture energy and deformation parameters（strain hardening capacity,fracture deffection,and crack initiation and propagation energy）.The degree of embrittlement was more noticeable in duplex stainless steel parent and weld-metal than in 316L stainless steel and became greater with the increase of aging *** degradation in impact toughness was discussed in relation to the observed precipitation of the intermetallic sigma phase in the microstructure of the stainless steel weldments and the corresponding fracture surface morphology.

关键词： Austenitic and duplex stainless steels Aging Instrumented impact Toughness

Proactive Load Balancing Mechanism for Fog Computing Supported by Parked Vehicles in IoV-SDN

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China Communications 2021年第2期18卷 271-289页

作者： ahmed Jawad Kadhim Jaber ibrahim Naser Ministry of Education General Directorate for Education in Al-QadisiyahAl-Qadisiyah 58002Iraq

Internet of Vehicles(IoV)is a new style of vehicular ad hoc network that is used to connect the sensors of each vehicle with each other and with other vehicles’sensors through the *** sensors generate different tasks that should be analyzed and processed in some given period of *** send the tasks to the cloud servers but these sending operations increase bandwidth consumption and *** computing is a simple cloud at the network edge that is used to process the jobs in a short period of time instead of sending them to cloud computing *** some situations,fog computing cannot execute some tasks due to lack of ***,in these situations it transfers them to cloud computing that leads to an increase in latency and bandwidth occupation ***,several fog servers may be fuelled while other servers are *** implies an unfair distribution of *** this research study,we shall merge the software defined network(SDN)with IoV and fog computing and use the parked vehicle as assistant fog computing *** can improve the capabilities of the fog computing layer and help in decreasing the number of migrated tasks to the cloud *** increases the ratio of time sensitive tasks that meet the *** addition,a new load balancing strategy is *** works proactively to balance the load locally and globally by the local fog managers and SDN controller,*** simulation experiments show that the proposed system is more efficient than VANET-Fog-Cloud and IoV-Fog-Cloud frameworks in terms of average response time and percentage of bandwidth consumption,meeting the deadline,and resource utilization.

关键词： IoV parked vehicles SDN fog computing load balancing

Direct Power Control Based on Dead-beat Function and Extended Kalman Filter for PV Systems

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Journal of Modern Power Systems and Clean Energy 2023年第3期11卷 863-872页

作者： Mostafa ahmed ibrahim Harbi Ralph Kennel Mohamed Abdelrahem Chair of High-Power Converter Systems(HLU) Technical University of Munich(TUM)80333 MunichGermany Department of Electrical Engineering Faculty of EngineeringAssiut UniversityAssiut 71515Egypt Department of Electrical Engineering Faculty of EngineeringMenoufia UniversityShebin El-Koum 32511Egypt IEEE

In this paper,a new proposal for the implementation of the well-known direct power control(DPC)technique in grid-connected photovoltaic(PV)systems is ***,the DPC is executed using a look-up table procedure based on the error between the actual and reference values of the active and reactive ***,the structure of the DPC is simple and results in a fast transient behavior of the inner current loop(injected currents).Therefore,in the current study,the DPC is reformulated using a dead-beat *** this formulation,the reference voltage vector(RVV)is obtained in theα-βreference ***,the switching states for the inverter can be obtained based on the sign of the components of the *** suggested DPC is compared with the conventional one and other switching tables,which are intended for performance ***,an extended Kalman filter(EKF)is utilized to eliminate all grid-voltage ***,the switching frequency of the proposed technique is minimized without any need for weighting factors or cost function *** overall control technique is validated using a hardware-in-the-loop(HIL)experimental set-up and compared with other schemes under different operating conditions.

关键词： Photovoltaic(PV)system direct power control(DPC) sensorless control switching frequency minimization weighting factor

Consecutive narrow and broad quasi-periodic fast-propagating wave trains associated with a flare

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 200-211页

作者： Xinping Zhou Yuandeng Shen Chengrui Zhou Zehao Tang ahmed ahmed ibrahim College of Physics and Electronic Engineering Sichuan Normal UniversityChengdu 610068China State Key Laboratory of Space Weather Chinese Academy of SciencesBeijing 100190China Yunnan Observatories Chinese Academy of SciencesKunming 650216China Department of Physics and Astronomy College of ScienceKing Saud UniversityP.O.Box 2455Riyadh 11451Saudi Arabia

The excitation mechanism of coronal quasi-period fast-propagating(QFP)wave trains remains *** Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory observations,we study a narrow and a broad QFP wave trains excited one after another during the successive eruptions of filaments hosted within a fan-spine magnetic system on October 20,*** consecutive occurrence of these two types of QFP wave trains in the same event provides an excellent opportunity to explore their excitation mechanisms and compare their physical *** observational results reveal that narrow and broad QFP wave trains exhibit distinct speeds,periods,energy fluxes,and relative intensity amplitudes,although originating from the same active region and being associated with the same GOES C2.9 *** wavelet analysis,we find that the narrow QFP wave train shares a similar period with the flare itself,suggesting its possible excitation through the pulsed energy release in the magnetic reconnection process that generated the accompanying *** the other hand,the broad QFP wave train appears to be associated with the energy pulses released by the successive expansion and unwinding of filament ***,it is plausible that the broad QFP wave train was also excited by the sequential stretching of closed magnetic field lines driven by the erupting *** findings shed light on the different excitation mechanisms and origins of the QFP wave trains.

关键词： narrow wave excitation

Deep Neural Artificial Intelligence for IoT Based Tele Health Data Anal

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Computers, Materials & Continua 2022年第3期70卷 4467-4483页

作者： Nithya Rekha Sivakumar ahmed Zohair ibrahim Department of Computer Sciences College of Computer and Information SciencesPrincess Nourah Bint Abdulrahman UniversityRiyadh11671Saudi Arabia

Tele health utilizes information and communication mechanisms to convey medical information for providing clinical and educational *** makes an effort to get the better of issues of health service delivery involving time factor,space and laborious terrains,validating cost-efficiency and finer ingress in both developed and developing *** health has been categorized into either real-time electronic communication,or store-andforward *** recent years,a third-class has been perceived as remote healthcare monitoring or tele health,presuming data obtained via Internet of Things(IOT).Although,tele health data analytics and machine learning have been researched in great depth,there is a dearth of studies that entirely concentrate on the progress of ML-based techniques for tele health data analytics in the IoT healthcare *** by this fact,in this work a method called,Weighted Bayesian and Polynomial Taylor Deep Network(WB-PTDN)is proposed to improve health prediction in a computationally efficient and accurate ***,the Independent Component Data Arrangement model is designed with the objective of normalizing the data obtained from the Physionet ***,with the normalized data as input,Weighted Bayesian Feature Extraction is applied to minimize the dimensionality involved and therefore extracting the relevant features for further health risk ***,to obtain reliable predictions concerning tele health data analytics,First Order Polynomial Taylor DNN-based Feature Homogenization is proposed that with the aid of First Order Polynomial Taylor function updates the new results based on the result analysis of old values and therefore provides increased transparency in decision *** comparison of proposed and existing methods indicates that the WB-PTDN method achieves higher accuracy,true positive rate and lesser response time for IoT based tele health data analytics than the traditional methods.

关键词： Telehealth internet of things independent component weighted bayesian first order polynomial taylor deep neural network

Finding an optimization of the plate element of Egyptian research reactor using genetic algorithm

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Nuclear Science and Techniques 2008年第5期19卷 314-320页

作者： WAHED Mohamed ibrahim Wesam EFFAT ahmed Mathematics Department Faculty of ScienceZagazic UniversityEgypt Atomic Energy Authority CairoEgypt

The second Egyptian research reactor ET-RR-2 went critical on the 27th of November *** National Center of Nuclear Safety and Radiation Control (NCNSRC) has the responsibility of the evaluation and assessment of the safety of this *** purpose of this paper is to present an approach to optimization of the fuel element plate. For an efficient search through the solution space we use a multi objective genetic algorithm which allows us to identify a set of Pareto optimal solutions providing the decision maker with the complete spectrum of optimal solutions with respect to the various *** aim of this paper is to propose a new approach for optimizing the fuel element plate in the *** fuel element plate is designed with a view to improve reliability and lifetime and it is one of the most important elements during the shut *** this present paper,we present a conceptual design approach for fuel element plate,in conjunction with a genetic algorithm to obtain a fuel plate that maximizes a fitness value to optimize the safety design of the fuel plate.

关键词：埃及核反应堆遗传算法燃料元件核技术

RESPONSE OF MICROPOLAR THERMOELASTIC SOLID WITH VOIDS DUE TO VARIOUS SOURCES UNDER GREEN NAGHDI THEORY

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Acta Mechanica Solida Sinica 2012年第2期25卷 197-209页

作者： Mohamed ibrahim ahmed Othman Sarhan Youssef Atwa Department of Mathematics Faculty of ScienceZagazig UniversityP.O.Box 44519ZagazigEgypt Higher Institute of Engineer Dept.of Eng.Math.and PhysicsShorouk AcademyEgypt Faculty of Science Department of mathematicsShaqra UniversityAL-QuwaiyahSaudi Arabia

Green-Naghdi （G-N） theory of thermoelasticity is employed to study the deformation of micropolar thermoelastic solid with voids considering the influence of various sources acting on the plane surface. The normal mode analysis is used to obtain the analytical expressions of the displacement components, force stress, coupled stress, variation of volume fraction field and temperature distribution. The computed results are presented graphically when the volume source is applied. Comparisons of type II and type III with and without micropolarity effect are made with the results predicted in the context of （G-N） theory.

关键词： micropolar thermoelastic solid volume fraction coupled stress energy dissipation,voids

Electromagnetic effects on the orbital motion of a charged spacecraft

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Research in Astronomy and Astrophysics 2014年第5期14卷 589-600页

作者： Yehia ahmed Abdel-Aziz Khalil ibrahim Khalil National Research Institute of Astronomy and Geophysics (NRIAG) Helwan Cairo 11721Egypt Department of Mathematics Hail University Hail 2440 Kingdom of Saudi Arabia

This paper deals with the effects of electromagnetic forces on the orbital motion of a spacecraft. The electrostatic charge which a spacecraft generates on its surface in the Earth＇s magnetic field will be subject to a perturbative Lorentz force. A model incorporating all Lorentz forces as a function of orbital elements has been developed on the basis of magnetic and electric fields. This Lorentz force can be used to modify or perturb the spacecraft＇s orbits. Lagrange＇s planetary equations in the Gauss variational form are derived using the Lorentz force as a perturbation to a Keplerian orbit. Our approach incorporates orbital inclination and the true anomaly. The numer- ical results of Lagrange＇s planetary equations for some operational satellites show that the perturbation in the orbital elements of the spacecraft is a second order perturba- tion for a certain value of charge. The effect of the Lorentz force due to its magnetic component is three times that of the Lorentz force due to its electric component. In addition, the numerical results confirm that the strong effects are due to the Lorentz force in a polar orbit, which is consistent with realistic physical phenomena that occur in polar orbits. The results confirm that the magnitude of the Lorentz force depends on the amount of charge. This means that we can use artificial charging to create a force to control the attitude and orbital motion of a spacecraft.

关键词： space vehicles -- atmospheric effects -- celestial mechanics -- kine-matics and dynamics

Analysis of stiffness and flexural strength of a reinforced concrete beam using an invented reinforcement system

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Frontiers of Structural and Civil Engineering 2021年第2期15卷 378-389页

作者： Nazim Abdul NARIMAN Martin HUSEK Ilham ibrahim MOHAMMAD Kaywan Othman ahmed Diyako DILSHAD ibrahim KHIDR Department of Civil Engineering Tishk International UniversitySulaimani46001Iraq Institute of Structural Mechanics Faculty of Civil EngineeringBrno University of TechnologyBrno331/95-60200Czech Republic

In this study,we conducted experimental tests on two specimens of reinforced concrete beams using a three-point bending test to optimize the flexure and stiffness *** first specimen is a reinforced concrete beam with an ordinary reinforcement,and the second specimen has an invented reinforcement system that consists of an ordinary reinforcement in addition to three additional bracings using steel bars and steel *** results of the flexure test were collected and analyzed,and the flexural strength,the rate of damage during bending,and the stiffness were *** element modeling was applied for both specimens using the LS-DYNA program,and the simulation results of the flexure test for the same outputs were *** results of the experimental tests showed that the flexural strength of the invented reinforcement system was significantly enhanced by 15.5%compared to the ordinary ***,the flexural cracks decreased to a significant extent,manifesting extremely small and narrow cracks in the flexure spread along the bottom face of the *** addition,the maximum deflection for the invented reinforced concrete beam decreased to 1/3 compared to that of an ordinary reinforced concrete *** results were verified through numerical simulations,which demonstrated excellent similarities between the flexural failure and the stiffness of the *** invented reinforcement system exhibited a high capability in boosting the flexure design and stiffness.

关键词： three-point flexure test softening stage flexural crack flexural strain