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A new technique for fault diagnosis in transformer insulating oil based on infrared spectroscopy measurements

High Voltage 2024年第2期9卷 319-335页

作者： mohamed m.f.darwish mohamed H.A.Hassan Nagat m.K.Abdel-Gawad matti Lehtonen Diaa-Eldin A.mansour Department of Electrical Engineering Faculty of Engineering at ShoubraBenha UniversityCairoEgypt Department of Electrical Engineering and Automation School of Electrical EngineeringAalto UniversityEspooFinland Department of Electrical Power Engineering Egypt-Japan University of Science and Technology(E-JUST)New Borg El-Arab CityEgypt Department of Electrical Power and machines Engineering Faculty of EngineeringTanta UniversityTantaEgypt

Condition monitoring of the insulating system within power transformers has a massive importance according to the electrical *** gas analysis(DGA)is frequently used for this ***,DGA lacks the necessary level of accuracy to identify all equipment faults,particularly in their initial stages of ***,it does not have the capability for real-time monitoring and relies on manual sampling and laboratory testing,causing potential delays in fault ***,the interpretation of DGA data necessitates specialised expertise,which may pose difficulties for smaller entities that have limited access to ***,the contribution of this research is to use infrared spectroscopy measurements as a new effective technique substituting the DGA method for fault diagnosis in insulating *** inception faults that were considered in this study were the electrical fault(discharges of high energy)and the thermal fault(300°Cmperaturefted especially for serving the simulation processes inside the laboratory for both types of inception ***,six samples of pure paraffinic mineral oil were taken to be degraded in the *** that,all of them besides another sample that were not subjected to any kind of faults were taken to be examined by fourier transform infrared(fTIR)spectroscopy to obtain an overview of the oil's behaviour in each fault *** that,the fTIR analysis was initially verified utilising the DGA ***,for further affirmation,the dielectric dissipation factor(DDf)for all samples was *** the final analysis,the verification tests provide experimental evidence about the outperformance of this new optical technique in detecting the transformer's inception faults in addition to proving its potential for being a superior alternative to the well-known traditional diagnostic techniques.

关键词： fault diagnosis spectroscopy

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Evaluating transient behaviour of large-scale photovoltaic systems during lightning events using enhanced finite difference time domain method with variable cell size approach

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High Voltage 2024年第3期9卷 636-647页

作者： Ibrahim Hetita Diaa-Eldin A.mansour Yang Han Ping Yang Congling Wang mohamed m.f.darwish matti Lehtonen Amr S.Zalhaf School of mechanical and Electrical Engineering University of Electronic Science and Technology of China(UESTC)ChengduChina Electrical Power and machines Engineering Department Faculty of EngineeringHelwan UniversityCairoEgypt Electrical Power and machines Engineering Department Faculty of EngineeringTanta UniversityTantaEgypt Department of Electrical Power Engineering Faculty of EngineeringEgypt-Japan University of Science and TechnologyAlexandriaEgypt Department of Electrical Engineering Faculty of Engineering at ShoubraBenha UniversityCairoEgypt Department of Electrical Engineering and Automation School of Electrical EngineeringAalto UniversityEspooFinland

Photovoltaic(PV)arrays are usually installed in open areas;hence,they are vulnerable to lightning strikes that can result in cell degradation,complete damage,service disruption,and increased maintenance *** a result,it is imperative to develop an effective and efficient lightning protection system by evaluating the transient behaviour of PV arrays during lightning *** aim is to evaluate the transient analysis of large-scale PV systems when subjected to lightning strikes using the finite difference time domain(fDTD)*** overvoltages are calculated at various points within the mounting *** optimise the fDTD method's execution time and make it more suitable for less powerful hardware,a variable cell size approach is ***,larger cell dimensions are used in the earthing system and smaller cell dimensions are used in the mounting *** fDTD method is utilised to calculate the temporal variation of transient overvoltages for large-scale PV systems under different scenarios,including variations in the striking point,soil resistivity,and the presence of a metal *** results indicate that the highest transient overvoltages occur at the striking point,and these values increase with the presence of a PV metal frame as well as with higher soil ***,a comparison is performed between the overvoltage results obtained from the fDTD approach and the partial element equivalent circuit(PEEC)method at the four corner points of the mounting systems to demonstrate the superior accuracy of the fDTD ***,a laboratory experiment is conducted on a small-scale PV system to validate the simulation *** calculated overvoltages obtained from the fDTD and PEEC methods are compared with the measured values,yielding a mean absolute error of 5%and 11%for the fDTD and PEEC methods,respectively,thereby confirming the accuracy of the fDTD simulation model.

关键词： transient behaviour finite

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PVC nanocomposites for cable insulation with enhanced dielectric properties,partial discharge resistance and mechanical performance

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High Voltage 2020年第4期5卷 463-471页

作者： Nagat m.K.Abdel-Gawad Adel Z.El Dein Diaa-Eldin A.mansour Hanaa m.Ahmed mohamed m.f.darwish matti Lehtonen Department of Electrical Power and machines Engineering Faculty of Engineering at ShoubraBenha UniversityCairoEgypt Department of High Voltage Networks Faculty of Energy EngineeringAswan UniversityAswanEgypt High Voltage and Superconductivity Laboratory Department of Electrical Power and Machines EngineeringFaculty of EngineeringTanta UniversityTantaEgypt Department of mathematics and Engineering Physics Faculty of Engineering at ShoubraBenha UniversityCairoEgypt Department of Electrical Engineering and Automation School of Electrical EngineeringAalto UniversityEspooFinland

The current study aims to develop polyvinyl chloride(PVC)nanocomposites with enhanced electrical and mechanical properties by incorporating titanium oxide(TiO_(2))nanoparticles within PVC *** loading of nanoparticles and different nanoparticle surface states were *** surface states are unfunctionalised,functionalised using vinyl silane and functionalised using amino *** choice of a most suitable surface state was a critical factor that guarantees a good dispersion of nanoparticles and consequently enhances the compatibility between TiO_(2)and PVC *** process followed in the PVC/TiO_(2)nanocomposites preparation,loaded with different wt.%of TiO_(2)nanoparticles,was the solvent *** dielectric properties measured here were the relative permittivity(ɛr),dielectric loss(tanδ),breakdown strength(AC and DC under uniform field)and the internal partial discharges(PDs)within insulation *** measurements have been performed under room temperature and at frequency ranged from 20 to 1.0 ***,the mechanical properties of the samples like elongation,elasticity modulus and tensile strength were also *** silane showed better improvements in both electrical and mechanical performances compared to the amino silane,especially in cases of high weight fractions of TiO_(2).This is because of the improvement in the PVC-TiO_(2)interfacial region arise from the similarity of polarity and surface tension values of vinyl silane with that of PVC matrix and TiO_(2)nanoparticles.

关键词： dielectric insulation resistance

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multi-timescale modeling and Dynamic Stability Analysis for Sustainable microgrids:State-of-the-art and Perspectives

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Protection and Control of modern Power Systems 2024年第3期9卷 1-35页

作者： mingyue Zhang Yang Han Yuxiang Liu Amr S.Zalhaf Ensheng Zhao Karar mahmoud mohamed m.f.darwish frede Blaabjerg the School of mechanical and Electrical Engineering University of Electronic Science and Technology of ChinaChengdu 611731China IEEE 不详 the University of Electronic Science and Technology of China(UESTC) ChengduChina Aswan University the School of Electrical Engineering Aalto UniversityFinland the Department of Electrical Engineering Faculty of Engineering at ShoubraBenha University the Department of EEA School of Electrical EngineeringAalto University

The increasing trend for integrating renewable energy sources into the grid to achieve a cleaner energy system is one of the main reasons for the development of sustainable microgrid(mG)*** typical power-electronized power systems,mGs make extensive use of power electronics converters,which are highly controllable and flexible but lead to a profound impact on the dynamic performance of the whole *** with traditional large-capacity power systems,mGs are less resistant to perturbations,and various dynamic variables are coupled with each other on multiple timescales,resulting in a more complex system instability *** meet the technical and economic challenges,such as active and reactive power-sharing,voltage,and frequency deviations,and imbalances between power supply and demand,the concept of hierarchical control has been introduced into mGs,allowing systems to control and manage the high capacity of renewable energy sources and ***,as the capacity and scale of the mG system increase,along with a multi-timescale control loop design,the multi-timescale interactions in the system may become more significant,posing a serious threat to its safe and stable *** investigate the multi-timescale behaviors and instability mechanisms under dynamic inter-actions for AC mGs,existing coordinated control strategies are discussed,and the dynamic stability of the system is defined and classified in this ***,the modeling and assessment methods for the stability analysis of multi-timescale systems are also ***,an outlook and discussion of future research directions for AC mGs are also presented.

关键词： Sustainable microgrid hierarchical control modeling model simplification multi-timescale dynamic stability analysis timescale decomposition.

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The impact of alpha-fetoprotein(AfP),child-turcotte-pugh(CTP)score and disease staging on the survival of hepatocellular carcinoma(HCC)patients:a retrospective cohort from single oncology center

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Oncology Research 2025年第1期33卷 149-160页

作者： NASSER mULLA YOUSEf KATIB ASIm m.ALmUGHAmSI DUAA S.ALKHAYAT mohamed mOSAAD SAmIR T.ALfOTIH RAWAN ALAOfI Department of Internal medicine Faculty of MedicineTaibah UniversityMadinah42278Saudi Arabia Department of Radiology Faculty of MedicineTaibah UniversityMadinah42278Saudi Arabia Department of Surgery Faculty of MedicineTaibah UniversityMadinah42278Saudi Arabia Department of Endemic and Infectious Diseases Suez Canal UniversityIsmailia41522Egypt King Salman bin Abdulaziz medical City Madinah42311Saudi Arabia Prince mohammed Bin Abdulaziz Hospital Madinah41511Saudi Arabia

Background:Hepatocellular carcinoma(HCC)is the most common cause of cancer-related death in Saudi *** study aimed to investigate the patterns of HCC and the effect of TNm staging,Alfa-fetoprotein(AfP),and Child-Turcotte Pugh(CTP)on patients’overall survival(OS).methods:A retrospective analysis was conducted on 43 HCC patients at a single oncology center in Saudi Arabia from 2015 to *** patients had to fulfill one of the following criteria:(a)a liver lesion reported as definitive HCC on dynamic imaging and/or(b)a biopsy-confirmed ***:The mean patient age of all HCC cases was 66.8 with a male-to-female ratio of 3.3:*** patients were stratified into two groups:viral HCC(n=22,51%)and non-viral HCC(n=21,49%).Among viral-HCC patients,55%were due to HBV and 45%due to *** was diagnosed in 79%of *** and sex did not significantly statistically differ in OS among viral and non-viral HCC patients(p-value>0.05).About 65%of patients had tumor size>5 cm during the diagnosis,with a significant statistical difference in OS(p-value=0.027).AfP was>400 ng/ml in 45%of the *** was a statistically significant difference in the OS in terms of AfP levels(p-value=0.021).A statistically significant difference was also observed between the CTP score and OS(p-value=0.02).CTP class B had the longest *** was the most common treatment provided to HCC patients followed by sorafenib *** was a significant statistical difference in OS among viral and non-viral HCC patients(p-value=0.008).Conclusions:The most common predictors for OS were the underlying cause of HCC,AfP,and tumor *** having non-viral etiology,a tumor size>5 cm,an AfP>400 ng/mL,and a CTP score class C were all negatively associated with OS.

关键词： Hepatocellular carcinoma Pattern Alpha-fetoprotein(AfP) Child-turcotte-pugh Progression free survival

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Dynamic Interaction Analysis of Coupled Axial-Torsional-Lateral mechanical Vibrations in Rotary Drilling Systems

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Structural Durability & Health monitoring 2025年第1期19卷 77-103页

作者： Sabrina meddah Sid Ahmed Tadjer Abdelhakim Idir Kong fah Tee mohamed Zinelabidine Doghmane madjid Kidouche Applied Automation Laboratory Faculty of Hydrocarbons and ChemistryUniversity of BoumerdesBoumerdes35000Algeria Institute of Electrical and Electronic Engineering(IGEE) University of BoumerdesBoumerdes35000Algeria Laboratory of the Electrification of Industrial Enterprises University of BoumerdesBoumerdes35000Algeria Electrical Engineering Department Mohamed Boudiaf University of M’silaM’sila28000Algeria Department of Civil and Environmental Engineering King Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Interdisciplinary Research Center for Construction and Building materials King Fahd University of Petroleum&Minerals(KFUPM)Dhahran31261Saudi Arabia

maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and *** achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is *** study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling *** study speciﬁcally investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency *** events not only hinder the efﬁciency of drilling but also lead to exhaustion and harm to the system’s components since they are difﬁcult to be detected and controlled in real *** study investigates the dynamic interactions of these vibrations,speciﬁcally in their high-frequency modes,usingﬁeld data obtained from measurement while ***ﬁndings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem *** obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control ***,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect ***,by exploiting theseﬁndings,the assessment of structural resilience in rotary drilling systems can be ***,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efﬁciency of rotary drilling systems in the petroleum industry.

关键词： Rotary drilling systems mechanical vibrations structural durability dynamic interaction analysis ﬁeld data analysis

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Wireless Sensor Networks Routing Attacks Prevention with Blockchain and Deep Neural Network

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Computers, materials & Continua 2022年第3期70卷 6127-6140页

作者： mohamed Ali Ibrahim A.Abd El-moghith mohamed N.El-Derini Saad m.darwish Higher Institute for Tourism Hotels and ComputerAl-SeyoufAlexandria21533Egypt Department of Information Technology Institute of Graduate Studies and ResearchAlexandria University21526Egypt Department of Computer and Systems Engineering Faculty of EngineeringAlexandria UniversityAlexandria21544Egypt

Routing is a key function inWireless Sensor Networks(WSNs)since it facilitates data transfer to base *** attacks have the potential to destroy and degrade the functionality ofWSNs.A trustworthy routing system is essential for routing security andWSN *** methods have been implemented to build trust between routing nodes,including the use of cryptographic methods and centralized ***,the majority of routing techniques are unworkable in reality due to the difficulty of properly identifying untrusted routing node *** the moment,there is no effective way to avoid malicious node *** a consequence of these concerns,this paper proposes a trusted routing technique that combines blockchain infrastructure,deep neural networks,and markov Decision Processes(mDPs)to improve the security and efficiency of WSN *** authenticate the transmission process,the suggested methodology makes use of a Proof of Authority(PoA)mechanism inside the blockchain *** validation group required for proofing is chosen using a deep learning approach that prioritizes each node’s *** are then utilized to determine the suitable next-hop as a forwarding node capable of securely transmitting *** to testing data,our routing system outperforms current routing algorithms in a 50%malicious node routing scenario.

关键词： Wireless sensor networks trusted routing deep neural network blockchain markov decision

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Small heat shock protein B8:from cell functions to its involvement in diseases and potential therapeutic applications

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Neural Regeneration Research 2025年第10期20卷 2872-2886页

作者： marta Chierichetti Riccardo Cristofani Valeria Crippa Veronica ferrari marta Cozzi Elena Casarotto Paola Pramaggiore Laura Cornaggia Guglielmo Patelli Ali mohamed margherita Piccolella mariarita Galbiati Paola Rusmini Barbara Tedesco Angelo Poletti Laboratory of Experimental Biology Dipartimento di Scienze Farmacologiche e Biomolecolari“Rodolfo Paoletti”(DiSFeB)Universitàdegli Studi di MilanoMilanItaly

Heat shock protein family B(small)member 8(HSPB8)is a 22 kDa ubiquitously expressed protein belonging to the family of small heat shock ***8 is involved in various cellular mechanisms mainly related to proteotoxic stress response and in other processes such as inflammation,cell division,and ***8 binds misfolded clients to prevent their aggregation by assisting protein refolding or degradation through chaperone-assisted selective *** line with this function,the pro-degradative activity of HSPB8 has been found protective in several neurodegenerative and neuromuscular diseases characterized by protein misfolding and *** cancer,HSPB8 has a dual role being capable of exerting either a pro-or an anti-tumoral activity depending on the pathways and factors expressed by the model of cancer under ***,HSPB8 exerts a protective function in different diseases by modulating the inflammatory response,which characterizes not only neurodegenerative diseases,but also other chronic or acute conditions affecting the nervous system,such as multiple sclerosis and intracerebellar *** note,HSPB8 modulation may represent a therapeutic approach in other neurological conditions that develop as a secondary consequence of other *** is the case of cognitive impairment related to diabetes mellitus,in which HSPB8 exerts a protective activity by assuring mitochondrial *** review aims to summarize the diverse and multiple functions of HSPB8 in different pathological conditions,focusing on the beneficial effects of its ***-based and alternative therapeutic approaches targeting HSPB8 and its regulated pathways will be discussed,emphasizing how new strategies for cell and tissue-specific delivery represent an avenue to advance in disease treatments.

关键词： aggregation autophagy cancer chaperone chaperone-assisted selective autophagy cognitive impairment HSPB8 neuroinflammation neuromuscular diseases therapy

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Electron Acceleration by microwave Radiation Inside a Rectangular Waveguide

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Plasma Science and Technology 2011年第3期13卷 357-361页

作者： B. f. mohamed A.m. GOUDA Plasma Physics Department N.R.C. Atomic Energy Authority Cairo Egypt

Electron dynamics in the fields associated with a transverse magnetic （Tm） wave propagating inside a rectangular waveguide is analytically studied. The relativistic momentum and energy equations for an electron are solved, which was injected initially along the propagation direction of the microwave. Expressions of the acceleration gradient and deflection angle are obtained. In principle, it is shown that the electron can be accelerated in this condition and there is no deflection when the electron is injected from the centre of the waveguide front. However, it is found that the acceleration gradient and deflection angle depend strongly on the parameters of the microwave （intensity, frequency, etc.） and the dimensions of the waveguide.

关键词： waveguide electron acceleration polarized microwave

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An adaptive neuro-fuzzy sliding mode controller for mImO systems with disturbance

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Chinese Journal of Chemical Engineering 2017年第4期25卷 463-476页

作者： mahmoud m.Saafan mohamed m.Abdelsalam mohamed S.Elksas Sabry f.Saraya fayez f.G.Areed Computers and Control Systems Engineering Department Faculty of EngineeringMansoura UniversityEgypt

This paper introduces the mathematical model of ammonia and urea reactors and suggested three methods for designing a special purpose controller. The first proposed method is Adaptive model predictive controller, the second is Adaptive Neural Network model Predictive Control, and the third is Adaptive neuro-fuzzy sliding mode controller. These methods are applied to a multivariable nonlinear system as an ammonia–urea reactor system. The main target of these controllers is to achieve stabilization of the outlet concentration of ammonia and urea, a stable reaction rate, an increase in the conversion of carbon monoxide(CO) into carbon dioxide(CO_2) to reduce the pollution effect, and an increase in the ammonia and urea productions, keeping the NH_3/CO_2 ratio equal to 3 to reduce the unreacted CO_2 and NH_3, and the two reactors' temperature in the suitable operating ranges due to the change in reactor parameters or external disturbance. Simulation results of the three controllers are compared. Comparative analysis proves the effectiveness of the suggested Adaptive neurofuzzy sliding mode controller than the two other controllers according to external disturbance and the change of parameters. moreover, the suggested methods when compared with other controllers in the literature show great success in overcoming the external disturbance and the change of parameters.

关键词： disturbance sliding ammonia stabilization outlet predictive monoxide dioxide overcome steam

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