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Flow field design and experiment of high-efficiency electrochemical milling with large machining area

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Chinese Journal of Aeronautics 2025年第2期38卷 617-630页

作者： Shili WANG Jia LIU Chuangye BAO Di ZHU college of mechanical&electrical engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Materials that are difficult to cut,such as titanium alloys,are widely used in large load-bearing integral components of aircraft,leading to great challenges for *** milling is a way for machining difficult-to-cut materials through Computer Numerical Control(CNC)trajectory *** a tilted large cathode machining surface and the cut-in feed mode,an efficient and low-cost method is obtained for machining the large integral components.A novel crossed and inclined structure of the flow mode is designed to realize electrochemical milling with a large tilted cathode *** to the vertical flow mode with one inlet,the proposed flow mode has two inlets that independently supply electrolytes,and the inclined channels make the flow field more *** field simulations are performed for both the vertical and proposed flow *** results show that the proposed flow mode avoids the random diversion of electrolytes and the ultralow flow velocity at both ends of the nozzle area,improving the velocity,uniformity,and stability of the *** inclination angle of the crossed and inclined flow field is ***,limit feed rate experiments are conducted in two modes,and the limit feed rate is 70 mm/min in the proposed mode.A sector workpiece of a large circular surface with approximately 8.77 mm thickness is machined 9 times by the cut-in electrochemical milling,the material removal rate is 4872 mm3/min,and the surface roughness is superior to 1.15μm.

关键词： Titanium alloy Electrochemical milling Flow mode design Flow field simulation Experiment

Bi-level Robust Clearing Framework of Integrated Electricity and Gas Market Considering Robust Bidding of Smart Energy Hubs

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Journal of Modern Power Systems and Clean Energy 2025年第1期13卷 351-364页

作者： Yanqiu Hou Minglei Bao Yi Ding the college of electrical engineering Zhejiang University

With the implementation of the integrated electricity and gas market(IEGM), the smart energy hubs(SEHs) tend to participate in the market clearing for the optimization of the energy purchase portfolio. Meanwhile, the renewable energy is mushrooming at different scales of energy systems, which can introduce utility-level and distribution-level uncertainties to the operation of the IEGM and SEHs, respectively. Considering the impacts of divergent uncertainties, there exist complicated interactions between the IEGM clearing and the robust bidding of SEHs. The lack of consideration of such interactions may lead to inaccurate modeling of the IEGM clearing and cause potential market inefficiency. To handle this, a bi-level robust clearing framework of the IEGM considering the robust bidding of SEHs is proposed, which simultaneously considers the impacts of utility-level and distribution-level uncertainties. The proposed framework is partitioned into two levels. The upper level is the robust clearing mechanism of the IEGM. At this level, the uncertainty locational marginal electricity and gas prices are derived considering the utility-level uncertainties and the uncertainty-based bidding of SEHs. Given the price signals deduced in the upper level, the lower-level robust bidding of the SEH seeks the optimal bidding strategies while hedging against distribution-level uncertainties. To address the proposed framework, an effective algorithm combining column-and-constraint generation(C&CG) algorithm with the best-response decomposition(BRD) algorithm is formulated. The devised algorithm can efficiently solve the individual robust optimization model and coordinate the interaction of two levels. Numerical experiments are carried out to verify the effectiveness of the proposed framework. Moreover, the impacts of uncertainties on the market clearing results along with the optimal biddings of SEHs are further demonstrated within the proposed framework.

关键词： Uncertainty Electricity Power generation Portfolios Optimization Stochastic processes Probabilistic logic

Fabrication and Mechano-sensing Characteristics of Bending Polypyrrole Actuator

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 240-245页

作者： CHEN Jinyou HU Wei School of Automotive engineering Hunan Financial&Industrial Vocational-technical CollegeHengyang 421002China college of mechanical and electrical engineering Hunan Agricultural UniversityChangsha 410128China

To prepare a conductive polymer actuator with decent performance,a self-built experimental platform for the preparation of polypyrrole film is *** of the essential goals is to examine the mechanical characteristics of the actuator in the presence of various combinations of process parameters,combined with the orthogonal test method of"four factors and three levels".The bending and sensing characteristics of actuators of various sizes are methodically examined using a self-made bending polypyrrole *** functional relationship between the bending displacement and the output voltage signal is established by studying the characteristics of the actuator sensor subjected to various degrees of *** experimental results reveal that the bending displacement of the actuator tip almost exhibits a linear variation as a function of length and *** the voltage reaches 0.8 V,the bending speed of the actuator tends to be ***,the mechanical properties of the self-assembled polypyrrole actuator are verified by the design and fabrication of the microgripper.

关键词： conductive polymer polypyrrole mechanical characteristics actuators sensing characteristics

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Progress and prospects for all-perovskite tandem solar cells

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Journal of Energy Chemistry 2025年第4期103卷 90-96页

作者： Qingyang Wu Jingwei Zhu Dewei Zhao Department of mechanical and electrical engineering Liaoning Provincial College of Communications college of Materials Science and engineering and engineering Research Center of Alternative Energy Materials and Devices Ministry of Education Sichuan University

All-perovskite tandem solar cells(TSCs) consist of a wide-bandgap(WBG,1.75-1.8 eV) top subcell and a low-bandgap(LBG,1.2-1.3 eV) bottom subcell,exhibit superior power conversion efficiencies(PCEs)compared to single-junction perovskite solar cells(PSCs).In addition,the advantages of lowtemperature solution preparation and low manufactu ring cost make the all-perovskite tandem solar cells widely concerned,and are considered to be one of the most potential next-generation high-performance thin film photovoltaic *** this perspective,we briefly summarize the state-of-the-art advances in monolithic all-perovskite TSCs focusing on the following aspects:LBG perovskite bottom subcells,WBG perovskite top subcells,and interconnecting layers(ICLs).We then discuss the primary strategies to improve their performa nce and finally highlight the perspective regarding the achievement of efficient and stable all-perovskite tandems.

关键词： Perovskite solar cells

Targeted Electrocatalysis for High-Performance Lithium–Sulfur Batteries

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Energy & Environmental Materials 2025年第2期8卷 118-128页

作者： Aqsa Nazir Anil Pathak Dambar Hamal Osama Awadallah Saeme Motevalian Ana Claus Vadym Drozd Bilal El-Zahab Department of mechanical and Materials engineering College of Engineering and Computing Florida International University

The intricate sulfur redox chemistry involves multiple electron transfers and complicated phase *** have been previously explored to overcome the kinetic barrier in lithium-sulfur batteries（LSBs）.This work contributes to closing the knowledge gap and examines electrocatalysis for enhancing LSB *** a strong chemical affinity for polysulfides,the electrocatalyst enables efficient adsorption and accelerated electron transfer *** cells with catalyzed cathodes exhibit improved rate capability and excellent stability over 500 cycles with 91.9% capacity retention at C/*** addition,cells were shown to perform at high rates up to 2C and at high sulfur loadings up to 6 mg *** electrochemical,spectroscopic,and microscopic analyses provide insights into the mechanism for retaining high activity,coulombic efficiency,and *** work delves into crucial processes identifying pivotal reaction steps during the cycling process at commercially relevant areal capacities and rates.

关键词： batteries catalysts electrochemistry electrodes energy materials

Flow field distribution and overpressure characteristics inside the crew compartment of a truck-mounted howitzer under the effect of muzzle blast

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Defence Technology(防务技术) 2025年第2期44卷 190-205页

作者： Shengcheng Wei Linfang Qian Yadong Xu Qiang Yin Xinyu Xiong School of mechanical engineering Nanjing University of Science and TechnologyNanjing210094China Northwest Institute of mechanical and electrical engineering Xianyang712099China

The muzzle blast overpressure induces disturbances in the flow field inside the crew compartment(FFICC)of a truck-mounted howitzer during the artillery *** overpressure is the primary factor preventing personnel from firing artillery within the *** investigate the overpressure characteristics of the FFICC,a foreign trade equipment model was used as the research object,and a numerical model was established to analyze the propagation of muzzle blast from the muzzle to the interior of the crew compartment under extreme firing *** comparative verification,the muzzle blast experiment included overpressure data from both the flow field outside the crew compartment(FFOCC)and the FFICC,as well as the acceleration data of the crew compartment structure(Str-CC).The research findings demonstrate that the overpressure-time curves of the FFICC exhibit multi-peak characteristics,while the pressure wave shows no significant *** enclosed nature of the cab hinders the dissipation of pressure wave energy within the FFICC,leading to sustained high-amplitude *** frameskin structure helps attenuate the impact of muzzle blast on the ***,local high overpressure caused by the convex or concave features of the cab's exterior significantly amplifies the overpressure amplitude within the FFICC.

关键词： Truck-mounted howitzer Muzzle blast Flow field inside the crew compartment(FFICC) Overpressure characteristics Flow-structure interaction

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Performance Enhancement of Aquivion-based Ionic Polymer Metal Composites for Cylindrical Actuators

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Journal of Bionic engineering 2025年第1期22卷 1-11页

作者： Xiaojie Tong Min Yu Guoxiao Yin Yuwei Wu Chengbo Tian Gengying Wang Jiangsu Provincial Key Laboratory of Bionic Functional Materials College of Mechanical and Electrical EngineeringNanjing University of Aeronautics and AstronauticsNanjing210016China

As a kind of ionic artificial muscle material,Ionic Polymer-Metal Composites(IPMCs)have the advantages of a low drive current,light weight,and significant *** are widely used in the fields of biomedicine,soft robots,***,the displacement and blocking force of the traditional sheet-type Nafion-IPMC need to be improved,and it has the limitation of unidirectional *** this paper,a new type of short side chain Aquivion material is used as the polymer in the *** cylindrical IPMC is prepared by extrusion technology to improve its actuation performance and realize multi-degree-of-freedom *** comparison to the traditional Nafion-IPMC,the ion exchange capacity,specific capacitance,and conductivity of Aquivion-IPMC are improved by 28%,27%,and 32%,respectively,and the displacement and blocking force are improved by 57%and 25%,*** cylindrical actuators can be deflected in eight *** indicates that Aquivion,as a polymer membrane for IPMC,holds significant application *** designing a cylindrical IPMC electrode distribution,the multi-degree-of-freedom deflection of IPMC can be realized.

关键词： Ionic polymer-metal composite Equivalent weight Aquivion Nafion Actuation performance

Gradient age-precipitation behavior induced by gradient nano-grain in Mg-Gd-Ag-Zr alloy

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Journal of Iron and Steel Research International 2025年第1期32卷 19-24页

作者： Bang-jun Li Jia-peng Sun Jing Han Guo-song Wu college of Materials Science and engineering Hohai UniversityNanjing 210024JiangsuChina School of mechanical and electrical engineering China University of Mining and TechnologyXuzhou 221116JiangsuChina

Gradient nano-grained structure is frequently engineered into metallic materials,including Mg alloys,to achieve superior combination of strength and ***,the influence of this microstructural feature on aging precipitation behavior remains inadequately *** this study,the age-precipitation behavior of a gradient nano-grained Mg-Gd-Ag-Zr alloy prepared via ultrasonic severe surface rolling was *** result indicates that the aging precipitation behavior exhibits a depth-dependent variation within this *** the nano-grained surface layer,hierarchicalβnano-precipitates are predominant,while at greater depths,the precipitates consist ofβnanoparticles located at grain boundaries,along with intragranularβ′andγ″*** formation ofβnano-precipitates deviates from the conventional precipitation behavior observed in Mg-Gd-Ag alloys,and is attributed to the high density of defects induced by the surface nano-grained *** finding advances our understanding of the precipitation behavior in the alloys with heterogeneous microstructure.

关键词： Mg alloy Gradient Precipitation Aging behavior Microstructure

Comparative Evaluation and Performance Analysis of Heat Exchangers Featured with Peened Surface

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Journal of Thermal Science 2025年第1期34卷 50-61页

作者： DINESHBABU Chinnadurai SHIVA SANKARAN Nallasamy VENKATESH RAJAKrishnan VENKATESH Rathinavelu Department of mechanical engineering Kongunadu College of Engineering and TechnologyTamil Nadu-621215India Department of mechanical engineering Selvam College of TechnologyNamakkalTamil Nadu-637003India Department of mechanical engineering Sona College of TechnologySalemTamil Nadu-636005India Department of mechanical engineering Saveetha School of EngineeringSaveetha Institute of Medical and Technical Sciences(SIMATS)Saveetha UniversityChennai 602105TamilnaduIndia

Heat exchangers have the potential for various engineering applications,and their performance is enriched by surface *** proposed system enriches the heat exchanger's performance by adapting a peened stainless steel(SS)surface blasted with copper,grinding,sand,and *** influences peened SS surface modified with a copper blast,grinding,sandblast,and iron blast on the surface morphology of shell and tube heat exchanger surface(STHE)is analyzed via tungsten heated cathode electron gun featured scanning electron microscope and observed coarse grain *** SS surface featured STHE performance is experimentally evaluated by different flow rates(30,60,90,and 120 L/min)underwater fluid medium functioned by the temperature ranges of 25-75℃ and its results are compared with computational fluid dynamic(CFD)/heat transfer research(HTRI)analyzed *** 60 L/min flow rate was spotted as an optimum value for both shell and tube side *** STHE is operated with a 60 L/min flow rate under the different peened surfaces and evaluated its Stanton number,Nusselt number,logarithmic mean temperature difference(LMTD),overall heat transfer coefficient,number of transfer units(NTU),effectiveness,and exergy *** iron blasted SS peened surface was observed to have better SHTE performance like Stanton number(0.0012),Nusselt number(2180),reduced LMTD of 31℃,improved overall heat transfer co-efficient of 2400 W/(m^(2)·K),better NTU of 0.5532,good effectiveness value of 0.45162,and hiked exergy efficiency of 10% respectively.

关键词： penned surface performance analysis stainless steel shell and tube heat exchanger

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