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Fuel cell stack design and modelling with a double-stage boost converter coupled to a single-phase inverter

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Clean Energy 2024年第1期8卷 188-196页

作者： Basem E.Elnagi Ahmed m.Ismaiel Hany S.E.mansour m.n.Abd-Alwahab Electrical Engineering Department Faculty of EngineeringSuez Canal UniversityIsmailia 41522Egypt

A comprehensive proton-exchange membrane fuel cell stack model was developed and integrated with a two-stage DC/DC boost *** was directly coupled to a single-phase(two levels-four pulses)inverter without a *** pulse-width modu-lation signal was used to independently regulate every converter *** converter was modelled using a mATLAB®/Simulink®environment and an appropriate voltage control *** analysis features of the suggested circuit were created and,through established experiments,the simulation results were verified.A single-phase(two levels-four pulses)inverter control circuit was tested and it produced a pure sinusoidal waveform with voltage *** matches the voltage of the network in terms of amplitude and frequency.A sinusoidal pulse-width modulation approach was performed using a single-phase(two levels-four pulses)pulse-width modulation *** results demonstrated an enhancement in the standard of the output wave and tuned the dead time with a reduction of 63μs compared with 180μs in conventional techniques.

关键词： PEm fuel cell pulse-width modulation single-phase inverter and double-stage DC/DC boost converter

Efficient Real-Time Devices Based on Accelerometer Usingmachine Learning for HAR on Low-Performancemicrocontrollers

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Computers, materials and Continua 2024年第1期81卷 1729-1756页

作者： Vi m.-T. Tran D.-n. Thuong V.T. Linh n.n. Tran D.-T. Faculty of Electrical and Electronic Engineering Phenikaa University Hanoi City 100000 Viet Nam Institute of Information Technology Vietnam Academy of Science and Technology Hanoi City 100000 Viet Nam Faculty of Information Technology and Communication Phuong Dong University Hanoi City 100000 Viet Nam Graduate University of Sciences and Technology Vietnam Academy of Science and Technology Hanoi City 100000 Viet Nam International School-Vietnam national University Hanoi City 100000 Viet Nam

Analyzing physical activities through wearable devices is a promising research area for improving health assessment. This research focuses on the development of an affordable and real-time Human Activity Recognition (HAR) system designed to operate on low-performance microcontrollers. The system utilizes data from a bodyworn accelerometer to recognize and classify human activities, providing a cost-effective, easy-to-use, and highly accurate solution. A key challenge addressed in this study is the execution of efficient motion recognition within a resource-constrained environment. The system employs a Random Forest (RF) classifier, which outperforms Gradient Boosting Decision Trees (GBDT), Support Vectormachines (SVm), and K-nearest neighbors (Knn) in terms of accuracy and computational efficiency. The proposed featuresAverage absolute deviation (AAD), Standard deviation (STD), Interquartile range (IQR), Range, and Root mean square (RmS). The research has conducted numerous experiments and comparisons to establish optimal parameters for ensuring system effectiveness, including setting a sampling frequency of 50 Hz and selecting an 8-s window size with a 40% overlap between *** conducted on both theWISDmpublic dataset and a self-collected dataset, focusing on five fundamental daily activities: Standing, Sitting, Jogging,Walking, andWalking the stairs. The results demonstrated high recognition accuracy, with the system achieving 96.7% on the WISDm dataset and 97.13% on the collected dataset. This research confirms the feasibility of deployingHAR systems on low-performance microcontrollers and highlights the system's potential applications in patient support, rehabilitation, and elderly care. © 2024 The Authors. Published by Tech Science Press.

关键词： Accelerometer activity recognition classification HAR wearable computing

Solar-assisted photocatalytic water splitting using defective UiO-66 solids from modulated synthesis

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nano Research 2024年第5期17卷 4134-4150页

作者： Celia m.Rueda-navarro maría Cabrero-Antonino Paula Escamilla Valentín Díez-Cabanes Dong Fan Pedro Atienzar Belén Ferrer Ignacio Vayá Guillaume maurin Herme G.Baldoví Sergio navalón Departamento de Química Universitat Politècnica de ValènciaCamino de Vera s/nValencia 46022Spain Instituto de Ciencia molecular(ICmOL) Universitat de ValènciaPaterna 46980Spain ICGm Univ.MontpellierCNRSENSCMMontpellier34095France Instituto de Tecnología Química(UPV-CSIC) Universitat Politècnica de ValènciaAvenida de los Naranjos s/nValencia 46022Spain

metal-organic frameworks(mOFs)are attracting increasing interests as photocatalysts for solar-driven hydrogen production from *** paper reports on a comparative study of using either acetic acid(AA)or trifluoroacetic acid(TFA)as the representative UiO-66 organic modulators for synthesizing visible light responsive UiO-66(Zr)-X(X:nH_(2) or nO_(2))photocatalysts for water *** results show that photocatalytic hydrogen generation from a water/methanol mixture can be improved by varying the nature and amount of the modulator employed to prepare the different UiO-66(Zr)-X(X:nH_(2) or nO_(2))solid ***-66(Zr)-nH_(2) was the most active photocatalyst,followed by UiO-66(Zr)-nO_(2),both prepared with 12 equivalents of AA with respect to the organic *** UiO-66(Zr)-nH_(2) solid was more active than the parent mOF in photocatalytic overall water splitting(OWS)(H_(2) and O_(2) production of 450 and 160μmol·g^(-1),respectively,in 5 h;apparent quantum yield(AQY)at 400 nm of 0.06%)in the absence of methanol and compares favourably with analogous *** on the photocatalytic activity of the most active solids of both series was obtained by means of a series of techniques,including ultraviolet-visible(UV-vis)diffuse reflectance,X-ray photoelectron spectroscopy(XPS),laser flash photolysis(LFP),electron spin resonance(ESR),photoluminescence and photoelectrochemical measurements together with density functional theory(DFT)*** results showed that organic acid modulators can be used to enhance the photocatalytic activity of missing linker UiO-66 defective materials in solar-powered water splitting.

关键词： heterogeneous photocatalysis metal-organic frameworks(mOFs) UiO-66 materials carboxylic acid modulators water splitting solar light

On examining the predictive capabilities of two variants of the PInn in validating localized wave solutions in the generalized nonlinear Schr?dinger equation

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Communications in Theoretical Physics 2024年第11期 163-176页

作者： K Thulasidharan n Sinthuja n Vishnu Priya m Senthilvelan Department of Physics Vellore Institute of Technology Department of Physics Anna University Department of mathematics Indian Institute of Science Department of nonlinear Dynamics Bharathidasan University

We introduce a novel neural network structure called strongly constrained theory-guided neural network(SCTgnn), to investigate the behaviour of the localized solutions of the generalized nonlinear Schr?dinger(nLS) equation. This equation comprises four physically significant nonlinear evolution equations, namely, the nLS, Hirota, Lakshmanan–Porsezian–Daniel and fifth-order nLS equations. The generalized nLS equation demonstrates nonlinear effects up to quintic order, indicating rich and complex dynamics in various fields of physics. By combining concepts from the physics-informed neural network and theory-guided neural network(Tgnn)models, the SCTgnn aims to enhance our understanding of complex phenomena, particularly within nonlinear systems that defy conventional patterns. To begin, we employ the Tgnn method to predict the behaviour of localized waves, including solitons, rogue waves and breathers, within the generalized nLS equation. We then use the SCTgnn to predict the aforementioned localized solutions and calculate the mean square errors in both the SCTgnn and Tgnn in predicting these three localized solutions. Our findings reveal that both models excel in understanding complex behaviour and provide predictions across a wide variety of situations.

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In-situ study of the microstructure evolution during tension of a mg-Y-Zn-Al alloy processed by rapidly solidified ribbon consolidation technique

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Journal of magnesium and Alloys 2024年第5期12卷 2024-2040页

作者： Jeno Gubicza Kristián máthis Péter nagy Péter Jenei Zoltán Hegedus Andrea Farkas Jozef Vesely Shin-ichi Inoue Daria Drozdenko Yoshihito Kawamura Department of materials Physics Faculty of ScienceEotvos Loránd UniversityPázmány P.sétány 1/ABudapest H-1117Hungary Department of Physics of materials Faculty of Mathematics and PhysicsCharles UniversityKe Karlovu 512116 Praha 2Czech Republic Deutsches Elektronen-Synchrotron DESY Notkestr.85Hamburg 22603Germany magnesium Research Center Kumamoto University2-39-1 KurokamiChuo-kuKumamoto 860-8555Japan

mg-Y-Zn-Al alloys processed by rapidly solidified ribbon consolidation(RSRC)technique exhibit an exceptional mechanical performance indicating promising application *** material has a bimodal microstructure consisting of fine recrystallized and coarse non-recrystallized grains with solute-rich stacking faults forming cluster arranged layers(CALs)and nanoplates(CAnaPs),or complete long period stacking ordered(LPSO)*** order to reveal the deformation mechanisms,in-situ synchrotron X-ray diffraction line profile analysis was employed for a detailed study of the dislocation arrangement created during tension in mg-0.9%Zn-2.05%Y-0.15%Al(at%)*** uncovering the effect of the initial microstructure on the mechanical performance,additional samples were obtained by annealing of the as-consolidated specimen at 300 and 400℃ for 2 *** heat treatment at 300℃ had no significant effect on the initial microstructure,its evolution during tension and,thus,the overall deformation behavior under tensile *** the other hand,annealing at 400℃ resulted in a significant increase of the recrystallized grains fraction and a decrease of the dislocation density,leading to only minor degradation of the mechanical *** maximum dislocation density at the failure of the samples corresponding to the plastic strain of 10-25% was estimated to be about 16-20×10^(14)m^(-2).The diffraction profile analysis indicated that most dislocations formed during tension were of non-basal and pyramidal types,what was also in agreement with the Schmid factor values revealed independently from orientation *** was also shown that the dislocation-induced Taylor hardening was much lower below the plastic strain of 3% than above this value,which was explained by a model of the interaction between prismatic dislocations and CAnaPs/LPSO plates.

关键词： mg-Zn-Y-Al alloy Long period stacking ordered(LPSO)phase Cluster arranged nanoplates(CAnaPs) Annealing Tension Dislocation density Hardening

Synergistic effect between Er-doped moS_(2)nanosheets and interfacial mo-n coupling phases for enhanced electrocatalytic hydrogen evolution

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Rare metals 2024年第3期43卷 1301-1308页

作者： nian-Peng Li Lei Zhang Hua Zhang Fan-Fei min Lei Wang sam Toan Xi-Jun Liu Guang-Zhi Hu State Key Laboratory of mining Response and Disaster Prevention and Control in Deep Coal mines School of Materials Science and EngineeringAnhui University of Science and TechnologyHuainan232001China Donghai Laboratory Zhoushan316021China Department of Chemical Engineering University of Minnesota-DuluthDuluthMN55812USA School of Ecology and Environmental Science Institute for Ecological Research and Pollution Control of Plateau LakesYunnan UniversityKunming650504China mOE Key Laboratory of new Processing Technology for non-Ferrous metals and materials Guangxi Key Laboratory of Processing for Non-Ferrous Metals and Featured MaterialsGuangxi UniversityNanning530004China

Hydrogen production via electrochemical water splitting is a promising and green *** one of the most representative transition metal sulfides layered materials,molybdenum disulfide(moS_(2))has immense potential for the hydrogen evolution reaction(HER).We successfully prepared a nitrogen-doped carbon(nC)in situ-grown erbium-doped moS_(2)polyhedral structure(Er-moS_(2)/nC)that incorporates an interfacial mo-n coupling phase.

关键词： hydrogen interfacial coupling

Large dinosaur egg accumulations and their significance for understanding nesting behaviour

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Geoscience Frontiers 2024年第5期15卷 467-488页

作者： L.Ezquerro R.Coimbra B.Bauluz C.núñez-Lahuerta T.Román-Berdiel m.moreno-Azanza Departamento de Geodinámica Estratigrafía y PaleontologíaFacultad de Ciencias GeológicasUniversidad Complutense de MadridC/JoséAntonio Novais1228040MadridSpain Aragosaurus-IUCA:Recursos Geológicos y Paleoambientales.Departamento de Ciencias de la Tierra.Facultad de Ciencias Universidad de ZaragozaC/Pedro Cerbuna 1250009 ZaragozaSpain museu da Lourinha LourinhaPortugal GeoBioTec Department of Earth SciencesNOVA School of Science and TechnologyUniversidade Nova de LisboaCaparicaPortugal GeoBioTec Departamento de GeocienciasUniversidade de AveiroAveiroPortugal Insitut Catalàde Paleoecologia Humana i EvolucióSocial(IPHES-CERCA) Zona Educacional 4Campus Sescelades URV(Edifici W3)43007 TarragonaSpain Departament d´Història i Història de l´Art Universitat Rovira i VirgiliAv.Catalunya 3543002 TarragonaSpain Geotransfer IUCA Departamento de Ciencias de La TierraFacultad de CienciasUniversidad de ZaragozaZaragozaSpain

The accurate identification of dinosaur egg accumulations as nests or clutches is crucial for understanding the reproductive behaviour of these extinct ***,existing methods often rely on the presence of complete eggs and embryo remains,and sedimentological criteria that are only applicable to well-structured *** this study,we introduce an innovative approach to characterize egg accumulations in structureless sediments,where traditional nest structures may not be *** methodology employs a unique combination of sedimentological,taphonomic,geochemical,and geophysical proxies for the study of egg *** applied this approach to the egg accumulation from Paimogo(Jurassic,Portugal),traditionally interpreted as a *** findings reveal that the Paimogo egg assemblage is a secondary deposit,resulting from a flooding event in a fluvial plain that dismantled several allosauroid and crocodylomorph *** eggshell vapor conductance results,coupled with sedimentological evidence,suggest that allosauroid dinosaurs buried their eggs in the dry terrain of overbank areas close to a main channel during the breeding season,likely during the dry season to prevent the embryos from *** research underscores the necessity of multidisciplinary approaches in interpreting egg accumulations and offers a novel methodology for studying these accumulations in structureless *** findings provide new insights into the breeding behaviour and nesting preferences of these extinct organisms,contributing to our understanding of dinosaur ecology.

关键词： Breeding behaviour Theropod Taphonomy Stable isotopes magnetic susceptibility Jurassic

Effect of proton irradiation on the optical properties of thermal control coating based on polystyrene with silica filler

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Propulsion and Power Research 2024年第1期13卷 1-11页

作者： n.I.Cherkashina V.I.Pavlenko m.m.mikhailov A.n.Lapin S.A.Yuriev R.V.Sidelnikov D.S.Romanyuk Belgorod State Technological University named after V.G.Shoukhov Kostyukov Str.46Belgorod 308012Russia Tomsk State University of Control Systems and Radioelectronics 40Prospect LeninaTomsk 634050Russia

This paper presents the results of studying the surface properties changes of a ther-moregulating coating based on polystyrene and silicaﬁller after proton irradiation with an en-ergy of 50 keV at afluence of 3�1015 cm�*** proton irradiation,the values of the contact angle of wetting with water increase by 3.5%and 14.9%for polystyrene and the coating,*** free surface energy(energy of the surface layer)of polystyrene and the coat-ings before and after proton irradiation was calculated using the Owens-Wendt-Rabel-Kaelble *** was a signiﬁcant increase in the polarity of the polystyrene surface(gp increased by a factor of 2.2)after proton *** the coating,an increase in gp by a factor of 3.89 was observed after proton *** changes in the coating were presented by IR Fourier spectroscopy.A slight decrease in the absorption intensity of all characteristic bands compared to the unirradiated sample was *** was found that the irradiation of the coating with protons led to the formation of macromolecules with hydroxyl,carbonyl,and carboxyl bonds,as well as the formation of dimeric and oligomeric siloxane *** was also found that after irradiation of a pure polystyrene sample with protons,the value of the solar absorption as increased by only 4.2%;whereas for the coating with silicaﬁller,the value of as increased by 28.6%.

关键词： Thermal control coating Proton irradiation Hydrophobicity Free surface energy Radiation crosslinking

Automating selective area electron diffraction phase identification using machine learning

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Journal of materiomics 2024年第4期10卷 896-905页

作者： m.mika n.Tomczak C.Finney J.Carter A.Aitkaliyeva nuclear Engineering Program in Department of materials Science University of Florida100 Rhines HallGainesville32611FLUSA Department of materials Science&Engineering Case Western Reserve University2111 Martin Luther King Jr DrCleveland44106OHUSA

Selective area electron diffraction(SAED)patterns can provide valuable insight into the structure of a ***,the manual identification of collected patterns can be a significant bottleneck in the overall phase classification *** this work,we utilize the recent advances in computer vision and machine learning(mL)to automate the indexing of SAED *** performance of six different mL algorithms is demonstrated using metallic plutonium-zirconium *** most successful approach trained a neural network(nn)to make a classification of the phase and zone axis,and then utilized a second nn to synthesize multiple independent predictions of different tilts in a single sample to make an overall phase *** results demonstrate that automated SAED phase identification using mL is a viable route to accelerate materials characterization.

关键词： Selective area electron diffraction machine learning Phase identification metallic fuels Pu alloys