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Energy budget of cold and hot gas-solid fluidized beds through CFD-DEM simulations

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Particuology 2024年第6期89卷 153-171页

作者： lei bi Yunpeng Jiao Chunjiang Liu Jianhua Chen Wei Ge School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072China State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China

Direct energy budget is carried out for both cold and hot flow in gas–solid fluidization systems.First,the energy paths are proposed from thermodynamic viewpoints.Energy consumption means total power input to the specific system,and it can be decomposed into energy retention and energy dissipation.Energy retention is the variation of accumulated mechanical energy in the system,and energy dissipation is the energy converted to heat by irreversible processes.Then based on the Computational Fluid Dynamics-Discrete Element Method(CFD-DEM)framework,different energy terms are quantified from the specific flow elements of fluid cells and particles as well as their interactions with the wall.In order to clarify the energy budget,it is important to identify which system is studied:the particle-fluid system or the particle sub-system.For the cold flow,the total energy consumption of the particle sub-system can well indicate the onset of bubbling and turbulent,while the variation of local energy consumption terms can reflect the evolution of heterogeneous structures.For the hot flow,different heat transfer mechanisms are analyzed and the solver is modified to reproduce the experimental results.The impact of the heat transfer mechanisms and heat production on energy consumption is also investigated.The proposed budget method has proven to be energy-conservative and easy to conduct,and it is hopeful to be applied to other multiphase flow systems.

关键词： Energy budget Gas-solid fluidization CFD-DEM Regime transition Heat transfer mechanism

Manipulating Nb-doped SrFeO_(3−δ)with excellent performance for proton-conducting solid oxide fuel cells

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Journal of Advanced Ceramics 2024年第5期13卷 579-589页

作者： Hailu Dai Hongzhe Du Samir Boulfrad Shoufu Yu lei bi Qinfang Zhang School of Materials Science and Engineering Yancheng Institute of TechnologyYancheng 224051China College of Science&Engineering Hamad Bin Khalifa UniversityDoha 34110Qatar School of Resource Environment and Safety Engineering University of South ChinaHengyang 421001China

Nb-doped SrFeO_(3−δ)(SFO)is used as a cathode in proton-conducting solid oxide fuel cells(H-SOFCs).First-principles calculations show that the SrFe0.9Nb0.1O_(3−δ)(SFNO)cathode has a lower energy barrier in the cathode reaction for H-SOFCs than the Nb-free SrFeO_(3−δ)cathode.Subsequent experimental studies show that Nb doping substantially enhances the performance of the SrFeO_(3−δ)cathode.Then,oxygen vacancies(VO)were introduced into SFNO using the microwave sintering method,further improving the performance of the SFNO cathode.The mechanism behind the performance improvement owing to VO was revealed using first-principles calculations,with further optimization of the SFNO cathode achieved by developing a suitable wet chemical synthesis route to prepare nanosized SFNO materials.This method significantly reduces the grain size of SFNO compared with the conventional solid-state reaction method,although the solid-state reaction method is generally used for preparing Nb-containing oxides.As a result of defect engineering and synthesis approaches,the SFNO cathode achieved an attractive fuel cell performance,attaining an output of 1764 mW·cm−2 at 700°C and operating for more than 200 h.The manipulation of Nb-doped SrFeO_(3−δ)can be seen as a“one stone,two birds”strategy,enhancing cathode performance while retaining good stability,thus providing an interesting approach for constructing high-performance cathodes for H-SOFCs.

关键词： SrFeO_(3−δ)-(SFO) cathode proton conductor solid oxide fuel cells(SOFCs)

A novel domain decomposition-based model for efficient dynamic predictions of large composite machine tools

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Science China Technological Sciences 2024年第6期67卷 1765-1782页

作者： YU YangBo JI Yu lei CHEN YanRen XU Kun bi QingZhen State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong University

We propose a large combined moving component composed of carbon fiber reinforced polymer(CFRP) laminates for making lightweight machine tools with high dynamic performance. The accurate dynamic prediction of composite machine tools is essential for the new generation machine tool. This paper aims to address two challenges in numerical dynamic modeling and the design of composite machine tools to enhance development efficiency.(1) Anisotropic composite laminates, which form the composite machine tool, exhibit coupling in various directions. We propose the generalized continuity condition of the boundary to tackle this dynamic modeling challenge.(2) Composite machine tools feature numerous composite-metal coupled structures.The mechanical model correction of isotropic metals is performed to address their dynamics. We take the example of a five-axis gantry machine tool with composite moving parts, establish a dynamic model for efficient prediction, and verify it through simulation and experimentation. The proposed method yields remarkable results, with an average relative error of only 3.85% in modal frequency prediction and a staggering 99.7% reduction in solution time compared to finite element analysis. We further discuss the dynamic performance of the machine tool under varied stacking angles and layer numbers of the composite machine tool. We propose general design criteria for composite machine tools to consider the modal frequency and manufacturing cost of machine tools.

关键词： machine tool dynamics carbon fiber reinforced polymer composite laminates

Nicotinamide adenine dinucleotide phosphate oxidase in pancreatic diseases:Mechanisms and future perspectives

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World Journal of Gastroenterology 2024年第5期30卷 429-439页

作者： Ya-Wei bi Long-Song Li Nan Ru Bo Zhang Xiao lei Department of Gastroenterology The First Medical Center of Chinese PLA General HospitalBeijing 100853China Department of Radiation Oncology Chinese PLA General HospitalBeijing 100853China

Pancreatitis and pancreatic cancer(PC)stand as the most worrisome ailments affecting the pancreas.Researchers have dedicated efforts to unraveling the mechanisms underlying these diseases,yet their true nature continues to elude their grasp.Within this realm,oxidative stress is often believed to play a causal and contributory role in the development of pancreatitis and PC.Excessive accumulation of reactive oxygen species(ROS)can cause oxidative stress,and the key enzyme responsible for inducing ROS production in cells is nicotinamide adenine dinucleotide phosphate hydrogen oxides(NOX).NOX contribute to pancreatic fibrosis and inflammation by generating ROS that injure acinar cells,activate pancreatic stellate cells,and mediate macrophage polarization.Excessive ROS production occurs during malignant transformation and pancreatic carcinogenesis,creating an oxidative microenvironment that can cause abnormal apoptosis,epithelial to mesenchymal transition and genomic instability.Therefore,understanding the role of NOX in pancreatic diseases contributes to a more in-depth exploration of the exact pathogenesis of these diseases.In this review,we aim to summarize the potential roles of NOX and its mechanism in pancreatic disorders,aiming to provide novel insights into understanding the mechanisms underlying these diseases.

关键词： Nicotinamide adenine dinucleotide phosphate hydrogen oxides Pancreatitis Pancreatic cancer Reactive oxygen species Mechanism

Design and preparation of highly crystalline K-intercalated W@PCN:an efficient material for aniline elimination

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Rare Metals 2024年第3期43卷 1337-1342页

作者： Hao-Fei Li Kai-Wen Yu Xiao-bi Jing lei Duan Yi-Yang Zhang School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou225002China School of Mechanical Engineering Yangzhou UniversityYangzhou225127China School of Material Science and Engineering Huazhong University of Science and TechnologyWuhan430071China School of Chemical Engineering and Materials Changzhou Institute of TechnologyChangzhou213032China Department of Basic Courses Army Engineering University of PLANanjing211101China

In this paper,we designed and prepared the polymeric carbon nitride-supported tungsten(W@PCN)materials.They were employed as the catalysts for photocatalytic oxidation of aniline in water.During the process,H_(2)O_(2)was initially generated via the PCN-catalyzed hydrophotolysis.Catalyzed by supported tungsten,aniline was oxidized by the in situ generated H_(2)O_(2)to obtain less toxicpoly aniline.

关键词： materials aniline crystalline

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A high-entropy spinel ceramic oxide as the cathode for proton-conducting solid oxide fuel cells

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Journal of Advanced Ceramics 2022年第5期11卷 794-804页

作者： Yangsen XU Xi XU lei bi School of Resource Environment and Safety Engineering University of South ChinaHengyang 421001China Department of Materials Imperial College London SW72BPUK

A high-entropy ceramic oxide is used as the cathode for the first time for proton-conducting solid oxide fuel cells(H-SOFCs).The Fe_(0.6)Mn_(0.6)Co_(0.6)Ni_(0.6)Cr_(0.6)O_(4)(FMCNC)high-entropy spinel oxide has been successfully prepared,and the in situ chemical stability test demonstrates that the FMCNC material has good stability against CO_(2).The first-principles calculation indicates that the high-entropy structure enhances the properties of the FMCNC material that surpasses their individual components,leading to lower O_(2)adsorption energy for FMCNC than that for the individual components.The HSOFC using the FMCNC cathode reaches an encouraging peak power density(PPD)of 1052 mW·cm^(-2)at 700℃,which is higher than those of the H-SOFCs reported recently.Additional comparison was made between the high-entropy FMCNC cathode and the traditional Mn_(1.6)Cu_(1.4)O_(4)(MCO)spinel cathode without the high-entropy structure,revealing that the formation of the high-entropy material allows the enhanced protonation ability as well as the movement of the O p-band center closer to the Fermi level,thus improving the cathode catalytic activity.As a result,the high-entropy FMCNC has a much-decreased polarization resistance of 0.057Ω·cm^(2)at 700℃,which is half of that for the traditional MCO spinel cathode without the high-entropy design.The excellent performance of the FMCNC cell indicates that the high-entropy design makes a new life for the spinel oxide as the cathode for HSOFCs,offering a novel and promising route for the development of high-performance materials for H-SOFCs.

关键词： proton-conducting oxides high-entropy oxides cathode solid oxide fuel cells(SOFCs)

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Successful preparation of BaCo_(0.5)Fe_(0.5)O_(3–δ)cathode oxide by rapidly cooling allowing for high-performance proton-conducting solid oxide fuel cells

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Journal of Advanced Ceramics 2023年第3期12卷 587-597页

作者： Yanru Yin Yanbin Zhou Yueyuan Gu lei bi School of Resource Environment and Safety Engineering University of South ChinaHengyang 421001China

A pure phase BaCo_(0.5)Fe_(0.5)O_(3–δ)(BCF),which cannot be obtained before,is successfully prepared in this study by using the calcination method with a rapid cooling procedure.The successful preparation of BCF allows the evaluation of this material as a cathode for proton-conducting solid oxide fuel cells(H-SOFCs)for the first time.An H-SOFC using the BCF cathode achieves an encouraging fuel cell performance of 2012 mW·cm–2 at 700,two℃-fold higher than that of a similar cell using the classical high-performance Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3–δ)(BSCF)cathode.First-principles calculations reveal the mechanism for the performance enhancement,indicating that the new BCF cathode significantly lowers the energy barriers in the oxygen reduction reaction(ORR)compared with the BSCF cathode.Therefore,improved cathode performance and fuel cell output are obtained for the BCF cell.The fuel cell using the BCF cathode also shows excellent long-term stability that can work stably for nearly 900 h without noticeable degradations.The fuel cell performance and long-term stability of the current BCF cell are superior to most of the H-SOFCs reported in previous reports,suggesting that BCF is a promising cathode for H-SOFCs.

关键词： BaCo_(0.5)Fe_(0.5)O_(3–δ) cathode proton conductor solid oxide fuel cells(SOFCs)

Taking advantage of Li-evaporation in LiCoO_(2) as cathode for proton-conducting solid oxide fuel cells

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Journal of Advanced Ceramics 2022年第12期11卷 1849-1859页

作者： Yangsen XU Shoufu YU Yanru YIN lei bi School of Resource Environment and Safety Engineering University of South ChinaHengyang 421001China

LiCoO_(2),a widely used electrode material for Li-ion batteries,was found to be suitable as a cathode material for proton-conducting solid oxide fuel cells(H-SOFCs).Although the evaporation of Li in LiCoO_(2) was detrimental to the Li-ion battery performance,the Li-evaporation was found to be beneficial for the H-SOFCs.The partial evaporation of Li in the LiCoO_(2) material preparation procedure led to the in-situ formation of the LiCoO_(2)+Co_(3)O_(4) composite.Compared to the cell using the pure phase LiCoO_(2) cathode that only generated moderate fuel cell performance,the H-SOFCs using the LiCoO_(2)+Co_(3)O_(4) cathode showed a high fuel cell performance of 1160 mW·cm^(-2) at 700℃,suggesting that the formation of Co_(3)O_(4) was critical for enhancing the performance of the LiCoO_(2) cathode.The first-principles calculation gave insights into the performance improvements,indicating that the in-situ formation of Co_(3)O_(4) due to the Li-evaporation in LiCoO_(2) could dramatically decrease the formation energy of oxygen vacancies that is essential for the high cathode performance.The evaporation of Li in LiCoO_(2),which is regarded as a drawback for the Li-ion batteries,is demonstrated to be advantageous for the H-SOFCs,offering new selections of cathode candidates for the H-SOFCs.

关键词： cathode composite proton conductor solid oxide fuel cells(SOFCs)

Application of a Neural Network to Store and Compute the Optical Properties of Non-Spherical Particles

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Advances in Atmospheric Sciences 2022年第12期39卷 2024-2039页

作者： Jinhe YU lei bi Wei HAN Xiaoye ZHANG Key Laboratory of Geoscience big Data and Deep Resource of Zhejiang Province School of Earth SciencesZhejiang UniversityHangzhou 310027China Center for Earth System Modeling and Prediction China Meteorological AdministrationBeijing 100081China Numerical Weather Prediction Center China Meteorological AdministrationBeijing 100081China Key Laboratory of Atmospheric Chemistry of China Meteorological Administration Institute of Atmospheric CompositionChinese Academy of Meteorological SciencesBeijing 100081China

Radiative transfer simulations and remote sensing studies fundamentally require accurate and efficient computation of the optical properties of non-spherical particles.This paper proposes a deep learning(DL)scheme in conjunction with an optical property database to achieve this goal.Deep neural network(DNN)architectures were obtained from a dataset of the optical properties of super-spheroids with extensive shape parameters,size parameters,and refractive indices.The dataset was computed through the invariant imbedding T-matrix method.Four separate DNN architectures were created to compute the extinction efficiency factor,single-scattering albedo,asymmetry factor,and phase matrix.The criterion for designing these neural networks was the achievement of the highest prediction accuracy with minimal DNN parameters.The numerical results demonstrate that the determination coefficients are greater than 0.999 between the prediction values from the neural networks and the truth values from the database,which indicates that the DNN can reproduce the optical properties in the dataset with high accuracy.In addition,the DNN model can robustly predict the optical properties of particles with high accuracy for shape parameters or refractive indices that are unavailable in the database.Importantly,the ratio of the database size(~127 GB)to that of the DNN parameters(~20 MB)is approximately 6810,implying that the DNN model can be treated as a highly compressed database that can be used as an alternative to the original database for real-time computing of the optical properties of non-spherical particles in radiative transfer and atmospheric models.

关键词： non-spherical particles light scattering super-spheroid model deep learning neural network

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