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Using macroscopic dynamics to study the effects of multiple factors to wear evolution mechanism

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Using macroscopic dynamics to study the effects of multiple ...

CSAA/IET International Conference on Aircraft Utility Systems (AUS 2024)

作者： Bowen Jia Shixun Pei Ziyu Hu Yuhang Chen Wei Hong MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics PGMF and School of Physics Huazhong University of Science and Technology Wuhan People's Republic of China School of Aero-engine Engineering Zhengzhou University of Aeronautics Zhengzhou 450046 People's Republic of China School of Environmental Science and Engineering Huazhong University of Science and Technology Wuhan 430074 People's Republic of China CYG Sunri Co. Ltd. Shenzhen People's Republic of China

ISBN: (数字)9781837242108

The occurrence of wear in mechanical systems is inevitable and the degree of wear on friction pairs of key components almost determines the life of mechanical equipment. Although the wear of friction pairs has been proven to follow the bathtub curve pattern, evolution mechanism is still unclear. Based on the linear damage mechanism at macroscopic time scale, this paper models the macroscopic dynamics by abstracting state variables of loss power, friction pair and debris characteristics. Furthermore, wear evolution mechanism is studied by Monte Carlo simulation within a reasonable range of parameters. The results show that wear mass action coefficient, wear mean and standard deviation action coefficient, and power factor coefficient of different wear types can affect the evolution direction of system. The reasonable combination of multiple factors can achieve reduction in power loss, decline in roughness of friction pair and decrease in the growth rate of debris mass. This study reveals the effects of multiple factors on the evolution of wear system from the macro level, which is of great significance for diagnosing equipment faults and prolonging mechanical life.

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Enhancement of Activated Coal Gangue Waste in Aging Resistance Performance of Asphalt Binder and Influence Mechanism from Interfacial Interaction Ability

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SSRN 2024年

作者： Li, Fan Wang, Linbing Li, Jianfeng Gao, Yang Su, Ningyi Faculty of Civil Engineering and Mechanics Kunming University of Science and Technology Kunming650500 China The Sensing and Perception Lab School of Environmental Civil Agricultural and Mechanical Engineering University of Georgia AthensGA30602 United States Shanxi Key Laboratory of Civil Engineering Disaster Prevention and Control College of Civil Engineering Taiyuan University of Technology Shanxi Taiyuan030024 China

This study conducted thermal activation approach to modify coal gangue (CG) waste from 450 ℃ to 900 ℃ and applied it to enhance aging resistance performance of asphalt binder. The surface morphology, mineral components and size distribution were analyzed via scanning electron microscope (SEM), X-ray diffraction (XRD) and laser granularity techniques. After 10, 20 and 40 h pressure aging vessel (PAV), rheological and chemical aging behaviors of various CG asphalt mastics (CGAM) were characterized by dynamic shear rheometer (DSR) and Fourier Transform infrared spectroscopy (FTIR). The K-B-G* parameter was calculated to measure interfacial interaction ability between asphalt and different fillers, aiming to establish correlation with aging indexes and explore enhancement mechanism of CG waste on aging resistance property of asphalt binder. The multi-scale results show that thermal activation process on CG waste results in particle size decreasing, surface roughness increasing and crystal lattice transferring. These variances contribute to increasing the interaction area of CG particles with asphalt binder. When calcination temperature elevates to 750 ℃, the activated CG exhibits strongest interaction ability with asphalt binder. There is a highly relation between K-B-G* and the aging indexes calculated by fatigue factor, rutting factor and infrared peak intensity at C=O band. This demonstrates that the stronger asphalt-filler interaction ability is, the better aging resistance property of asphalt mastic is. Thermal activation on CG waste has positive influence on enhancing the aging resistance property of corresponding asphalt mastic, and the suggested calcination temperature is 750 ℃. © 2024, The Authors. All rights reserved.

关键词： Particle size

Facile Preparation and Catalytic Property of a Sandwich Composite Membrane

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SSRN 2024年

作者： Zhen, Haozhi Chen, Xi Ma, Yongdi Wu, Qianqian Wang, Qiong Wang, Yuxuan Guo, Zhongxu Wang, Jianzu Shi, Lei State Key Laboratory of Separation Membranes and Membrane Processes Tiangong University Tianjin300387 China School of Environmental Science and Engineering Tiangong University Tianjin300387 China School of Materials Science and Engineering Tiangong University Tianjin300387 China Department of Pharmaceutical and Engineering Hebei Chemical and Pharmaceutical Vocational Technology College Shijiazhuang050026 China

Membrane as a support for metal nanocatalysts, can greatly enhance the catalytic activity of metal nanoparticles and promote the efficient production and separation of products. In this study, a novel sandwich-structured composite membrane was designed and facilely fabricated by using palladium nanocatalysts as the core catalytic layer and two different structured PVDF layers as the outer layers. The composite membrane was used as a reaction interface as well as a separation barrier between reactants and products, efficiently realizing the catalytic oxidation of benzyl alcohol and convenient separation of the product benzaldehyde. The membrane was detailedly characterized and the effects of the membrane structure and various reaction conditions on the catalytic oxidation were systematically investigated. Results indicated that the reaction could be conveniently carried out under very mild experimental conditions, obtaining the product benzaldehyde with a very high selectivity of 93.17%. The successful implementation of the sandwich membrane for the production of chlorine-free benzaldehyde provides a new method for the interface reaction. © 2024, The Authors. All rights reserved.

关键词： Composite membranes

Recommendation of PHM algorithms based on fuzzy information fusion

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IFAC-PapersOnLine 2020年第3期53卷 31-36页

作者： Mingliang Suo Xue Liu Ke Ma Laifa Tao Science & Technology on Reliability & Environmental Engineering Laboratory Beijing 100191 China

The diversity of algorithms and the complication of application scenarios makes it difficult for PHM (Prognostics and Health Management) developers to accurately choose an appropriate algorithm when performing algorithm design. To make up for the aforementioned shortcoming, this paper proposes an algorithm recommendation system suitable for PHM. Specifically, according to the PHM architecture, a PHM database is designed to assist in the mining of recommended knowledge and the execution of recommended strategies. Subsequently, a recommendation system is developed that mainly includes hybrid data processing, similarity measurement, and recommendation decision making. Therein, two recommendation strategies, based on Fuzzy C-Means (FCM) method and weighted information fusion, are designed to cope with two kinds of actual requirements. Finally, the recommendation of remaining useful life (RUL) prediction associated with the Commercial Modular Aero-Propulsion System Simulation (C-MAPSS) data set is employed as an application case to verify the effectiveness of the proposed recommendation system.

关键词： From PHM CBM+ considerations to Maintenance Diagnostics Prognostics Reasoning Decision Support Data-driven Maintenance Decision-making

The Formation of Photogranules by Mechanical Agitation Under High Salinity Stress: Characteristics and Mechanism

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SSRN 2024年

作者： Li, Weirun Zhu, Jing Li, Zhipeng Zhang, Guoyu Xie, Binghan Chen, Hongying Xing, Xiaodi Li, Lingjie Yang, Yixuan Zhao, Shuyu You, Hong Ding, Yi Tan, Haili Xia, Yiying Huang, Yuelin Chen, Yinxi Zhang, Mingqi State Key Laboratory of Urban Water Resource and Environment School of Environment Harbin Institute of Technology Harbin150090 China School of Marine Science and Technology Harbin Institute of Technology at Weihai Weihai264209 China School of Environmental Science and Engineering Yangzhou University Yangzhou225127 China Marine College Shandong University at Weihai Weihai264209 China

Photogranulation, as a new way of combining granulation technology and photoautotrophs, has attracted wide attention in recent years, especially in the field of mariculture wastewater. However, the photogranulation process and mechanism are still unclear. A mechanically stirred photogranular sequencing batch bioreactor (MS-PSBR) was setup for exploring the formation process and mechanism of photogranules. The photogranulation process could be divided into three stages: (1) the adaptation period (1-13 d), during which organisms aggregated with each other to form microalgae knots and some large nucleating bioflocs;(2) the photogranules formation period (13-40 d), which showed bioflocs shifting to initial photogranules with obvious core and clear boundary. (3) the photogranules maturity period (40-65 d), being dominant by photogranules with the advantages of high mechanical strength, excellent performance. Noticeably, the mature photogranules exhibited obviously stratified structure, with tightly coiled filamentous microalgae in the outermost layer, certain microalgae and bacteria in the intermediate layer and heterotroph mainly in the innermost layer. This layered structure enabled efficient utilization of oxygen and nutrients, thus maintaining the structural stability and excellent wastewater treatment efficiency of photogranules. When mature photogranules dominated, the removal rates of NH4+-N, TN and PO43-P stabilized at 97.54%, 61.78% and 50.80%, respectively. In order to further explore changes of interaction energy, the XDLVO theory was applied. A decreasing trend was observed in the energy barrier to be overcome during photogranulation, which was more conducive to the assembly of photogranules and the maintenance of structural stability. Therefore, this study revealed the formation process and mechanism of photogranules under mechanical agitation and high salinity stress. It also provided a new efficient and environmentally friendly option for the treatment of

关键词： Microalgae

Lateral Layered Heterostructure Bimetallic Selenides Bi2se3-Fese2@C for Ultra-Sensitive Electrochemical Sensing Platform

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SSRN 2023年

作者： Gao, Faming Song, Dandan Huang, Xingge Han, Minze Xu, Xiaoyue Li, Guoqiang Wang, Xiaotong Zhao, Yisong Hebei Key Laboratory of Heavy Metal Deep-Remediation in Water and Resource Reuse Yanshan University Qinhuangdao066004 China Key Laboratory of Applied Chemistry College of Environmental and Chemical Engineering Yanshan University Qinhuangdao066004 China State Key Laboratory of Food Nutrition and Safety Tianjin University of Science and Technology Tianjin300457 China

Selenides possess more electroactive unsaturated edge sites and superior redox activity, due to larger ionic radius together with low electronegativity of Se in comparation with sulfur and oxygen. However, mono-metallic selenides still suffer from the intrinsic limitations of low conductivity and electrochemical activity, which hinders their application in electrochemical sensor. Herein, a carbon-encapsulated bimetallic selenides (Bi2Se3-FeSe2@C) composite with lateral layered heterostructure was synthesized and employed as electrode material for electrochemical biosensing. The formed few-layered Bi2Se3-FeSe2@C lateral heterostructure with a large surface area possesses superb electrochemical properties and abundant immobilized sites toward acetylcholinesterase (AChE). The robust AChE-NF/Bi2Se3-FeSe2@C/GCE biosensor exhibited promising monocrotophos detection performance along with high sensitivity, a wide linear range (10-5~10 µg mL−1) and low limit of detection (1.51x10-13 M). © 2023, The Authors. All rights reserved.

关键词： Electrochemical sensors

Resolving the amine-promoted hydrolysis mechanism of N₂O₅under tropospheric conditions

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Proceedings of the National Academy of sciences of the United States of America 2022年第39期119卷 e2205668119-e2205668119页

作者： Zhou, Chuan Li, Bai Zhang, Jingyan Henkelman, Graeme Francisco, Joseph S. Li, Lei Shenzhen Key Laboratory of Micro/Nano-Porous Functional Materials Department of Materials Science and Engineering Southern University of Science and Technology Shenzhen 518055 China Department of Chemistry The University of Texas at Austin Austin 78712 TX United States Institute for Computational Engineering and Sciences The University of Texas at Austin Austin 78712 TX United States Department of Earth and Environmental Sciences University of Pennsylvania Philadelphia 19104 PA United States

Hydrolysis of N2O5 under tropospheric conditions plays a critical role in assessing the fate of O3, OH, and NOx in the atmosphere. However, its removal mechanism has not been fully understood, and little is known about the role of entropy. Herein, we propose a removal path of N2O5 on the water clusters/droplet with the existence of amine, which entails a low free-energy barrier of 4.46 and 3.76 kcal/mol on a water trimer and droplet, respectively, at room temperature. The free-energy barrier exhibits strong temperature dependence;a barrierless hydrolysis process of N2O5 at low temperature (≤150 K) is observed. By coupling constrained ab initio molecular dynamics (constrained AIMD) simulations with thermodynamic integration methods, we quantitively evaluated the entropic contributions to the free energy and compared NH3-, methylamine (MA)-, and dimethylamine (DMA)-promoted hydrolysis of N2O5 on water clusters and droplet. Our results demonstrate that methylation of NH3 stabilizes the product state and promotes hydrolysis of N2O5 by reducing the free-energy barriers. Furthermore, a quantitative analysis of the internal coordinate distribution of the reaction center and the relative position of surrounding species reveals that the significant entropic contribution primarily results from the ensemble effect of configurations observed in the AIMD simulations. Such an ensemble effect becomes more significant with more water molecules included. Lowering the temperature effectively minimizes the entropic contribution, making the hydrolysis more exothermic and barrierless. This study sheds light on the importance of the promoting effect of amines and the entropic effect on gas-phase hydrolysis reactions, which may have far-reaching implications in atmospheric chemistry. © 2022 the Author(s).

关键词： amines anharmonic effect entropy hydrolysis N2O5

Boosting electrocatalytic hydrogen generation by a renewable porous wood membrane decorated with Fe-doped NiP alloys

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Journal of Energy Chemistry 2021年第5期30卷 23-33页

作者： Bin Hui Jian Li Yun Lu Kewei Zhang Hongjiao Chen Dongjiang Yang Liping Cai Zhenhua Huang State Key Laboratory of Bio-Fibers and Eco-Textiles Shandong Collaborative Innovation Center of Marine Biobased Fiber and Ecological TextileInstitute of Marine Biobased MaterialsSchool of Environmental Science and EngineeringQingdao UniversityQingdao 266071ShandongChina Key Laboratory of Bio-based Materials Science and Technology of Ministry of Education Research Center of Wood Bionic Intelligent ScienceNortheast Forestry UniversityHarbin 150040HeilongjiangChina Research Institute of Wood Industry Chinese Academy of ForestryBeijing 100091China College of Engineering University of North Texas3940 NElm St.DentonTX 76207USA

Porous biomass electrodes have emerged as a critical material for electrocatalytic hydrogen evolution reaction(HER).However,most approaches for synthesizing porous electrodes from biomass require high energy consumption,which is resulted from the smash of biomass and the undergoing of serial ***,a self-supported wood-derived"breathable"membrane is utilized directly as electrodes for highefficient HER via an assembly of Fe-doped NiP *** well-designed hierarchical porous structures in natural wood membrane(NWM)are unusually beneficial for electrolytes accessibility and hydrogen gas *** obtained wood-derived membrane exhibits a high electrocatalytic activity and good cycling durability in acidic and alkaline ***,the Fe_(0.074) NiP alloys/NWM electrode affords a large current density of 100 m A cm^(-2) at extremely low overpotentials of 168 mV in acidic electrolyte and174 m V in alkaline *** functional theory calculations unveil that the Fe atom doped in NiP alloys can create much more charge accumulation around Fe and Ni active sites,which helps decrease the △GH_(*)and △G_(H2O)and significantly promote the HER *** new insight will promote further explorations of economic,high-efficient,and biodegradable wood-derived electrocatalysts for HER.

关键词： Wood membrane Hierarchical structures Electrocatalysis:Hydrogen generation

Wind Tunnel and Numerical Study of Wind Pressure Coefficients on a Medieval Swedish Church

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SSRN 2024年

作者： Liu, Wei Mattsson, Magnus Widström, Torun Claesson, Leif Tianjin Key Laboratory of Indoor Air Environmental Quality Control School of Environmental Science and Engineering Tianjin University 92 Weijin Road Tianjin300072 China Department of Civil and Architectural Engineering KTH Royal Institute of Technology Brinellvägen 23 Stockholm100 44 Sweden Department of Building Engineering Energy Systems and Sustainability Science University of Gävle Gävle801 76 Sweden

Air infiltration has great importance regarding energy, comfort, moisture and dust deposition in naturally ventilated historical buildings like churches. In these buildings, air infiltration is driven by stack effect and wind. When assessing the wind effect, reasonable estimation of wind pressure coefficients is crucial. Local wind pressure coefficients are significantly affected by the shape of the building and turbulence generated by its geometrical features, which – for moderately large churches – typically consist of main building body and window recesses, gable roof, tower, apse, and sacristy. This study conducted wind tunnel and numerical investigations of wind pressure coefficients at a church, with gradual addition of these features. Wind pressure was measured on a small-scale model in a wind tunnel, while computational fluid dynamics (CFD) simulations were carried out for both small-scale and full-scale models. By comparing the experimental and numerical results, the SST k − ω turbulence model showed the best accuracy, yielding CFD results in good agreement with wind tunnel measurements. Most challenging was predicting the strong negative wind pressures occurring on a flat roof. Building structures like tower, apse, and sacristy had significant impact on the wind pressures on the central, main building body. This study adds knowledge on wind pressure effects by commonly occurring building components, with particular reference to churches and similar buildings. © 2024, The Authors. All rights reserved.

关键词： Computational fluid dynamics