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Room and cryogenic deformation behavior of AZ61 and AZ61-xCaO(x=0.5,1 wt.%)alloy

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Journal of Magnesium and Alloys 2024年第5期12卷 1996-2009页

作者： Umer Masood Chaudry Hafiz Muhammad Rehan Tariq Nooruddin Ansari Soo Yeol Lee Tea-Sung Jun department of Mechanical engineering Incheon National UniversityIncheon 22012Republic of Korea Research Institute for engineering and Technology Incheon National UniversityIncheon 22012Republic of Korea department of Materials Science&engineering Chungnam National UniversityDaejeon 34134Republic of Korea

This study investigates the influence of CaO(0.5,1(wt.%))alloying on the microstructural evolution,texture development and deformation behavior of AZ61 magnesium *** uniaxial tension tests at room(RT)and cryogenic(CT,-150℃)temperature were performed to investigate the twinability and dislocation behavior and its consequent effect on flow stress,ductility and strain hardening *** results showed that the AZ61-1CaO exhibited superior strength/ductility synergy at RT with a yield strength(YS)of 223 MPa and a ductility of 23% as compared to AZ61(178 MPa,18.5%)and AZ61-0.5CaO(198 MPa,21%).Similar trend was witnessed for all the samples during CT deformation,where increase in the YS and decrease in ductility were *** Mtex tools based in-grain misorientation axis(IGMA)analysis of RT deformed samples revealed the higher activities of prismatic slip in AZ61-CaO,which led to superior ***,subsequent EBSD analysis of CT deformed samples showed the increased fraction of fine{10-12}tension twins and nucleation of multiple{10-12}twin variants caused by higher local stress concentration at the grain boundaries,which imposed the strengthening by twin-twin ***,the detailed investigations on strengthening contributors showed that the dislocation strengthening has the highest contribution towards strength in all samples.

关键词： Magnesium Twinning Twinning variant EBSD Cryogenic deformation

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A Framework for Enhancing Privacy and Anonymity in Blockchain-Enabled IoT Devices

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Computers, Materials & Continua 2024年第3期78卷 4263-4282页

作者： Muhammad Saad Muhammad Raheel Bhutta Jongik Kim Tae-Sun Chung department of Artificial Intelligence Ajou UniversitySuwon443-749Korea department of electrical and Computer engineering University of Utah Asia CampusIncheon21985Korea department of Artificial Intelligence Chungnam National UniversityDaejeon34134Korea

With the increase in IoT(Internet of Things)devices comes an inherent challenge of *** the world today,privacy is the prime concern of every *** one’s privacy and keeping anonymity throughout the system is a desired functionality that does not come without inevitable trade-offs like scalability and increased complexity and is always exceedingly difficult to *** challenge is keeping confidentiality and continuing to make the person innominate throughout the *** address this,we present our proposed architecture where we manage IoT devices using blockchain *** proposed architecture works on and off blockchain integrated with the closed-circuit television(CCTV)security camera fixed at the rental *** this framework,the CCTV security camera feed is redirected towards the owner and renter based on the smart contract *** entity(owner or renter)can see the CCTV security camera feed at one *** is no third-party dependence except for the CCTV security camera deployment *** contributions include the proposition of framework architecture,a novel smart contract algorithm,and the modification to the ring signatures leveraging an existing cryptographic *** are made based on different systems’security and key management *** an empirical study,our proposed algorithm performed better in key generation,proof generation,and verification *** comparing similar existing schemes,we have shown the proposed architectures’*** now,we have developed this system for a specific area in the real ***,this system is scalable and applicable to other areas like healthcare monitoring systems,which is part of our future work.

关键词： Privacy anonymity blockchain IoT smart contracts

Image enhancement with intensity transformation on embedding space

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CAAI Transactions on Intelligence Technology 2024年第1期9卷 101-115页

作者： Hanul Kim Yeji Jeon Yeong Jun Koh department of Applied Artificial Intelligence Seoul National University of Science and TechnologySeoulSouth Korea department of Computer Science and engineering Chungnam National UniversityDaejeonSouth Korea

In recent times,an image enhancement approach,which learns the global transformation function using deep neural networks,has gained ***,many existing methods based on this approach have a limitation:their transformation functions are too simple to imitate complex colour transformations between low-quality images and manually retouched high-quality *** order to address this limitation,a simple yet effective approach for image enhancement is *** proposed algorithm based on the channel-wise intensity transformation is ***,this transformation is applied to the learnt embedding space instead of specific colour spaces and then return enhanced features to *** this end,the authors define the continuous intensity transformation(CIT)to describe the mapping between input and output intensities on the embedding ***,the enhancement network is developed,which produces multi-scale feature maps from input images,derives the set of transformation functions,and performs the CIT to obtain enhanced *** experiments on the MIT-Adobe 5K dataset demonstrate that the authors’approach improves the performance of conventional intensity transforms on colour space ***,the authors achieved a 3.8%improvement in peak signal-to-noise ratio,a 1.8%improvement in structual similarity index measure,and a 27.5%improvement in learned perceptual image patch ***,the authors’algorithm outperforms state-of-the-art alternatives on three image enhancement datasets:MIT-Adobe 5K,Low-Light,and Google HDRþ.

关键词： computer vision deep learning image enhancement image processing

Generalized polynomial chaos expansion by reanalysis using static condensation based on substructuring

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Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 819-836页

作者： D.LEE S.CHANG J.LEE department of Automotive engineering Hanyang UniversitySeoul 04763Republic of Korea School of Mechanical engineering Chungnam National UniversityDaejeon 34134Republic of Korea department of Mechanical Robotics and Energy EngineeringDongguk UniversitySeoul 04620Republic of Korea

This paper presents a new computational method for forward uncertainty quantification(UQ)analyses on large-scale structural systems in the presence of arbitrary and dependent random *** method consists of a generalized polynomial chaos expansion(GPCE)for statistical moment and reliability analyses associated with the stochastic output and a static reanalysis method to generate the input-output data *** the reanalysis,we employ substructuring for a structure to isolate its local regions that vary due to random *** allows for avoiding repeated computations of invariant substructures while generating the input-output data *** substructuring with static condensation further improves the computational efficiency of the reanalysis without losing ***,the GPCE with the static reanalysis method can achieve significant computational saving,thus mitigating the curse of dimensionality to some degree for UQ under high-dimensional *** numerical results obtained from a simple structure indicate that the proposed method for UQ produces accurate solutions more efficiently than the GPCE using full finite element analyses(FEAs).We also demonstrate the efficiency and scalability of the proposed method by executing UQ for a large-scale wing-box structure under ten-dimensional(all-dependent)random inputs.

关键词： forward uncertainty quantification(UQ) generalized polynomial chaos expansion(GPCE) static reanalysis method static condensation substructuring

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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

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

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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°C

关键词： fault diagnosis spectroscopy

Extension of Distribution Transformer Life in the Presence of Smart Inverter-based Distributed Solar Photovoltaic Systems

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 88-95页

作者： Kanhaiya Kumar Saran Satsangi Ganesh Balu Kumbhar department of electrical and Electronics engineering Motihari College of EngineeringMotihariBiharIndia department of electrical engineering National Institute of Technology(NIT)PatnaPatnaBiharIndia department of electrical engineering Indian Institute of Technology(IIT)RoorkeeRoorkeeUttarakhandIndia

A transformer is an essential but expensive power delivery equipment for a distribution *** many distribution utilities worldwide,a sizable percentage of transformers are near the end of their designed *** the same time,distribution utilities are adopting smart inverter-based distributed solar photovoltaic(SPV)systems to maximize renewable *** central objective of this paper is to propose a methodology to quantify the effect of smart inverter-based distributed SPV systems on the aging of distribution *** proposed method is first tested on a modified IEEE-123 node distribution *** that,the procedure is applied to a practical distribution system,i.e.,the Indian Institute of Technology(IIT)Roorkee campus,*** transformer aging models,alongside advanced control functionalities of grid-tied smart inverter-based SPV systems,are implemented in *** open-source simulation tool(OpenDSS)is used to model distribution *** analyze effectiveness of various inverter functionalities,time-series simulations are performed using exponential load models,considering daily load curves from multiple seasons,load types,current harmonics,*** show replacing a traditional inverter with a smart inverter-based SPV system can enable local reactive power generation and may extend the life of a distribution *** results demonstrate,simply by incorporating smart inverter-based SPV systems,transformer aging is reduced by 15%to 22%in comparison to SPV systems operating with traditional inverters.

关键词： Distribution transformer loss of life smart inverter functions solar photovoltaic systems thermal models Volt-VAr control

Model Reference Adaptive Controller for Simultaneous Voltage and Frequency Restoration of Autonomous AC Microgrids

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Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1194-1202页

作者： Farahnaz Ahmadi Yazdan Batmani Hassan Bevrani department of electrical engineering University of KurdistanSanandajIran

In an autonomous droop-based microgrid,the sys-tem voltage and frequency(VaF)are subject to deviations as load *** the existence of various control methods aimed at correcting system frequency deviations at the second-ary control level without any communication network,the chal-lenges associated with these methods and their abilities to simul-taneously restore microgrid VaF have not been fully *** this paper,a multi-input multi-output(MIMO)model ref-erence adaptive controller(MRAC)is proposed to achieve VaF restoration while accurate power sharing among distributed generators(DGs)is *** proposed MRAC,without any communication network,is designed based on two meth-ods:droop-based and inertia-based *** the microgrid,the suggested design procedure is started by defining a model reference in which the control objectives,such as the desired settling time,the maximum tolerable overshoot,and steady-state error,are ***,a feedback-feedforward con-troller is established,of which the gains are adaptively tuned by some rules derived from the Lyapunov stability *** some simulations in MATLAB/SimPowerSystem Tool-box,the proposed MRAC demonstrates satisfactory perfor-mance.

关键词： AC microgid communication-free secondary control droop-based method inertia-based method model reference adaptive controller(MRAC) simultaneous voltage and frequency restoration

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Bifunctional electrolyte addition for longer life and higher capacity of aqueous zinc-ion hybrid supercapacitors

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Rare Metals 2024年第10期43卷 5060-5069页

作者： Fan Zhang Si-Qi Li Li-Nan Xia Chao Yang Lei Li Kai-Ming Wang Chen-Liang Xu Yuan-Yuan Feng Bin Zhao Fei Shen Xiao-Gang Han Ling-Yun Zhu School of Electric Power Civil Engineering and ArchitectureShanxi University State Key Laboratory of electrical Insulation and Power Equipment School of Electrical EngineeringXi’an Jiaotong University department of Science Materials and engineering National University of Singapore School of Materials Science and engineering Anhui University

Owing to uncontrolled and uneven electrodeposition and side reactions,Zn metal anodes inevitably suffer from issues such as dendrite growth,hydrogen evolution reactions,and surface *** paper proposes an efficient strategy to address these critical issues for realizing long-life and high-capacity aqueous zinc-ion hybrid supercapacitors （ZHSCs） by incorporating low-concentration (0.05 mol·L-1) redox RbI electrolyte ***,rubidium cations have the ability to influence the negative Zn electrode surface via an electrostatic shielding mechanism,effectively protecting the electrode and minimizing undesired side *** an aqueous solution,iodide anions actively solvate Zn2+ions by stabilizing and modulating the solvation shell surrounding Zn2+.Moreover,the presence of iodide ions promotes the uniform deposition of Zn2+species by selective adsorption onto the electrode *** synergistic effect of the electrostatic shielding and halogen ions enables the realization of aqueous symmetric Zn||Zn cells with a substantial cycle life of more than 2000 h Additionally,when applied to commercial activated carbon（AC）,the proposed strategy facilitates the development of aqueous ZHSCs,exhibiting high specific capacitances(148.8 F·g-1at 4 A·g-1) and ultra-long cycling stability.

关键词： Aqueous zinc-ion hybrid supercapacitor Rubidium iodide Synergistic effects of anions and cations Zn dendrite Zn metal anode