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Elastohydrodynamic Lubrication Interface Stiffness and Damping Considering Asperity Lateral Contact

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Acta Mechanica Solida Sinica 2024年第1期37卷 109-123页

作者： Zhiqiang Gao Yu Zhang xian wei Yanfang Zhu Lixia Peng weiping Fu Wen Wang School of Mechanical and Precision Instrument Engineering Xi'an University of TechnologyXi'an 710048China School of Intelligent Manufacturing Panzhihua UniversityPanzhihua 617000China Material Corrosion and Protection Key Laboratory of Sichuan Province Sichuan University of Light Chemical TechnologyYibin 644002China School of Mechanical Engineering Anyang Institute of TechnologyAnyang 455099China

Elastohydrodynamic lubrication(EHL)point contact occurs between two rough surfaces at the mesoscopic level,while the interaction of rough surfaces involves contact between asperities at the microscale *** most cases,the contact between asperities within an interface takes the form of lateral contact rather than peak *** devoid of contact asperities are filled with lubricating ***,conventional models often oversimplify lateral contact forms as interactions between asperities and a smooth,rigid *** simplifications fail to accurately represent the true contact conditions and can lead to inaccuracies in the analysis of EHL’s contact *** address this issue,we have developed a novel EHL interface model comprising two rough *** model allows us to explore the influence of asperity height,contact angle,and contact azimuth angle on EHL interface performance.

关键词： EHL interface Asperity lateral contact Contact stiffness Damping

Critical Role of Ethylene-Propylene Block Copolymer in Impact Polypropylene Copolymer

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Chinese Journal of Polymer Science 2024年第3期42卷 344-351,I0007页

作者： Yu-Hui Tang Na Zhang wei Bao wei jiang Yuan Lin Zhao-Hui Su State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

Ethylene-propylene block copolymer(EbP) is a vital component in impact polypropylene copolymer(IPC), yet its distribution in the multiphase composite material and how it influences the phase structure and the mechanical properties are not well understood. In this work,four IPCs were investigated by atomic force microscopy-infrared(AFM-IR) to assess the phase compositions in situ, based on which in conjunction with the chain microstructure information obtained ex situ the distributions of the copolymer components were derived for each alloy. For the IPCs whose EbP comprises long P and long E segments, the EbP fraction was found to phase separate from the rubber and the PP matrix to form the cores of the disperse particles with the E-P segmented copolymer(EsP). In contrast, in the IPC with EbP composed of long P and short E segments, the EbP fraction formed an outer shell for the rubber particles with the cores comprising the EsP alone, and this IPC, containing a lower E comonomer content than its counterpart, exhibited both better impact resistance and higher flexural modulus. These results clarify how the chain structure of EbP governs the phase morphology in IPC, which in turn impacts the properties of the composite material.

关键词： Impact polypropylene copolymers AFM-IR Ethylene-propylene block copolymers Core-shell rubber particles

Flexural behavior of textile reinforced mortar-autoclaved lightweight aerated concrete composite panels

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Frontiers of Structural and Civil Engineering 2024年第5期18卷 776-787页

作者： Liying GUO Mingke DENG wei ZHANG Tong LI Yangxi ZHANG Mengyu CAO xian HU Department of Civil Engineering Xi’an University of Architecture and TechnologyXi’an 710055China Key Lab of Structural Engineering and Earthquake Resistance Ministry of Education(XAUAT)Xi’an 710055China Scene engineering design institute Xi’an 710016China Dahua Group Shang hai 200062China

To improve the deficiencies of prefabricated autoclaved lightweight aerated concrete(ALC)panel such as susceptibility to cracking and low load-bearing capacity,a textile-reinforced mortar-autoclaved lightweight aerated concrete(TRM-ALC)composite panel was developed in this *** group of reference ALC panels and five groups of TRM-ALC panels were fabricated and subjected to four-point flexural *** was applied on the tensile side of the ALC panels to create *** variable parameters were the plies of textile(one or two),type of textile(basalt or carbon),and whether the matrix(without textile)was applied on the compression side of *** results showed that a bonding only 8-mm-thick TRM layer on the surface of the ALC panel could increase the cracking load by 180%−520%.The flexural capacity of the TRM-ALC panel increased as the number of textile layers *** reinforcement of the matrix on the compressive side could further enhance the stiffness and ultimate loadbearing capacity of the TRM-ALC *** panels with basalt textile failed in flexural mode,with the rupture of fabric *** with carbon textile failed in shear mode due to the ultra-high tensile strength of *** addition,analytical models related to the different failure modes were presented to estimate the ultimate load-carrying capacity of the TRM-ALC panels.

关键词： prefabricated autoclaved lightweight aerated concrete panel textile-reinforced mortar cracking load flexural capacity stiffness

Wellbore-heat-transfer-model-based optimization and control for cooling downhole drilling fluid

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Petroleum Science 2024年第3期21卷 1955-1968页

作者： Chao Wang He Liu Guo-wei Yu Chen Yu xian-Ming Liu Peng Huang Yangtze University Jingzhou434023HubeiChina State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing2249China CNPC Bohai Drilling Engineering Co. LtdTianjin300280China Exploration Development and Construction Engineering Division of PetroChina Jidong Oilfield Company Tangshan63200HebeiChin Henan University of Urban Construction Pingdingshan467036HenanChina

To address the two critical issues of evaluating the necessity of implementing cooling techniques and achieving real-time temperature control of drilling fluids underground in the current drilling fluid cooling technology,we first established a temperature and pressure coupled downhole heat transfer model,which can be used in both water-based and oil-based drilling ***,fourteen factors,which could affect wellbore temperature,were *** on the standard deviation of the downhole temperature corresponding to each influencing factor,the influence of each factor was *** influencing factors that can be used to guide the drilling fluid's cooling technology were drilling fluid thermal conductivity,drilling fluid heat capacity,drilling fluid density,drill strings rotation speed,pump rate,viscosity,ROP,and injection *** nondominated sorting genetic algorithm was used to optimize these six parameters,but the optimization process took 182 *** these eight parameters'influence rules with the nondominated sorting genetic algorithm can reduce the optimization time to 108 ***,the downhole temperature has been demonstrated to increase with the inlet temperature increasing linearly under quasi-steady *** this law and PID,the downhole temperature can be controlled,which can reduce the energy for cooling the surface drilling fluid and can ensure the downhole temperature reaches the set value as soon as possible.

关键词： Drilling Cooling Influencing factors Analysis Optimization Control

Colloid-facilitated release of polybrominated diphenyl ethers at an e-waste recycling site: evidence from undisturbed soil core leaching experiments

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Frontiers of Environmental Science & Engineering 2024年第2期18卷 91-101页

作者： Zebin Huo Mengjun Xi Lianrui Xu Chuanjia jiang wei Chen College of Environmental Science and Engineering Ministry of Education Key Laboratory of Pollution Processes and Environmental CriteriaTianjin Key Laboratory of Environmental Remediation and Pollution ControlNankai UniversityTianjin 300350China

Polybrominated diphenyl ethers (PBDEs), a class of persistent organic pollutants, have been frequently detected in soil at e-waste recycling sites. However, the key factors controlling the transport of PBDEs from surface soil to the vadose zone and groundwater are unclear. Here, colloid-enhanced leaching of PBDEs from undisturbed soil cores collected at an e-waste recycling site in Tianjin, China, is reported. Spatially heterogeneous release of colloids and PBDEs was observed in all the tested soil cores under chemical and hydrodynamic perturbations, indicating the presence of preferential flow paths. Colloid concentration in the effluent significantly increased as ionic strength decreased (from 10 to 0.01 mmol/L), probably due to the stronger electrostatic repulsion between colloidal particles and the soil matrix at lower ionic strength. In contrast, colloid mobilization was not significantly affected by the changes in pH of the influent (from 4.0 to 10.0) and flow rate (from a Darcy velocity of 1.5 to 6.0 cm/h). The concentrations of 2,2′,3,3′,4,4′,5,5′,6,6′-decabromodiphenyl ether (BDE-209), the predominant PBDE congener at the site, detected in the leachate (ranging from 1.09 to 3.43 ng/L) were much lower than previously reported results from packed column leaching tests, and were positively correlated with colloid concentrations. This indicates that remobilization of colloids at e-waste recycling sites can promote the leaching and downward migration of PBDEs from surface soil. The findings highlight the potential risk of surface soil PBDE contamination to groundwater quality and call for further understanding of colloid-facilitated transport for predicting the fate of PBDEs at e-waste recycling sites.

关键词： Polybrominated diphenyl ether Colloid-facilitated transport E-waste recycling site Undisturbed soil core Groundwater quality

Processing of a low-costγ-γ'NiPtAl coating with improved oxidation resistance

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Rare Metals 2024年第6期43卷 2832-2841页

作者： Yan jiang Liang-Liang wei Jian He Hong-Bo Guo School of Materials Science and Engineering Beihang UniversityBeijing 100191China Key Laboratory of High-Temperature Structural Materials and Protective Coatings Ministry of Industry and Information TechnologyBeihang UniversityBeijing 100191China

A novelγ-γ'(Ni solid solution—Ni_(3)Al)NiPtAl coating was produced on advanced single-crystal(SC)superalloy N5 by electroplating of a thin Pt coating with~3μm in thickness followed by heat treatment at 1000℃in *** comparison,a traditionalγ-γ'NiPtAl coating was also produced by electroplating of a thick Pt coating with~6μm in thickness followed by heat treatment at 1100℃in *** novel coating has a mass gain of~0.5 mg·cm^(-2)after 100 h 1-h cyclic oxidation at 1150℃,showing better oxidation resistance than the traditional *** oxide scale mostly consisting ofα-Al_(2)O_(3)grew on the novel coating because the element Cr from the SC alloy substrate contributes to the formation ofα-Al_(2)O_(3).Pt content in the novel coating has significant effect on the oxidation *** optimized Pt content in the coating is about 16 at%,which is helpful to reduce the diffusion of harmful elements from the substrate into the coating but also to reduce the cost of the coating.

关键词： γ-γ'NiPtAl coating Platinum Oxidation Al_(2)O_(3) Superalloy

Impact of Carbon Chain Structures in the Backbone on the Flexibility of Modified Polyarylene Sulfide Resins: Molecular Dynamics Simulations and Mesoscopic Analysis

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Chinese Journal of Polymer Science 2024年第4期42卷 544-557页

作者： Chi Zhang Rong Liu Jing-Yuan Liu Wen-wei jiang Key Laboratory of Fine Chemical Engineering and Functional Materials School of Chemical EngineeringSichuan UniversityChengdu610065China

In the domain of high-performance engineering polymers, the enhancement of mechanical flexibility in poly(phenylene sulfide) (PPS) resins has long posed a significant challenge. A novel molecular structure, designated as PP-He-IS, wherein imide rings and an aliphatic hexylene chain are covalently incorporated into the PPS backbone to enhance its flexibility, is introduced in this study. Molecular dynamics (MD) simulations are employed to systematically explore the effects of diversifying the backbone chain structures by substituting phenyl units with alkyl chains of varying lengths, referred to as PP-A-IS where “A” signifies the distinct intermediary alkyl chain configurations. Computational analyses reveal a discernable decrement in the glass transition temperature (Tg) and elastic modulus, counterbalanced by an increment in yield strength as the alkyl chain length is extended. Notably, the PP-He-IS variant is shown to exhibit superior yield strength while simultaneously maintaining reduced elastic modulus and Tg values, positioning it as an advantageous candidate for flexible PPS applications. Mesoscopic analyses further indicate that structures such as PP-He-IS, PP-Pe-IS, and PP-Bu-IS manifest remarkable flexibility, attributable to the presence of freely rotatable carbon-carbon single bonds. Experimental validation confirms that a melting temperature of 504 K which is lower than that of conventional PPS, and lower crystallinity are exhibited by PP-He-IS, thereby affording enhanced processability without compromising inherent thermal stability. Novel insights into the strategic modification of PPS for mechanical flexibility are thus furnished by this study, which also accentuates the pivotal role played by molecular dynamics simulations in spearheading high-throughput investigations in polymer material modifications.

关键词： Molecular dynamics simulations Polyarylene Sulfide Main-chain modifications Flexibility Aliphatic hexylene chain

Nanodiamond/Ti_(3)C_(2) MXene-coated quartz crystal microbalance humidity sensor with high sensitivity and high quality factor

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Rare Metals 2024年第6期43卷 2719-2729页

作者： Yao Yao Qiao Chen Yan-Qi Li xian-He Huang wei-wei Ling Zhe-MiaoXie Jia-QiWang Chang-Ming Chen College of Communication Engineering Chengdu University of Information TechnologyChengdu 610225China School of Automation Chongqing University of Posts and TelecommunicationsChongqing 400065China School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu 611731China Advanced Micro-/Nano-Devices Lab Department of Systems Design EngineeringUniversity of WaterlooWaterlooON N2L 3GlCanada

To address the challenge of achieving both high sensitivity and a high quality factor in quartz crystal microbalance(QCM)humidity sensors,a nanodiamond(ND)/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor was *** material characteristics of ND,Ti_(3)C_(2)MXene,and ND/Ti_(3)C_(2)MXene composite were analyzed by transmission electron microscopy(TEM)and Fourier transform infrared(FTIR)*** experimental results demonstrated that the hydrophilic ND nanoparticles coated on Ti_(3)C_(2) MXene nanosheet prevented the self-stacking of Ti_(3)C_(2)MXene and enhanced the sensitivity of Ti_(3)C_(2) MXene-based QCM humidity ***,the high mechanical modulus of Ti_(3)C_(2) MXene material helped ND/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor to achieve a high quality factor(>20,000).ND/Ti_(3)C_(2)MXene compositecoated QCM humidity sensor exhibited a sensitivity of 82.45 Hz/%RH,a humidity hysteresis of 1.1%RH,fast response/recovery times,acceptable repeatability,and good stability from 11.3%RH to 97.3%*** response mechanism of ND/Ti_(3)C_(2) MXene composite-coated QCM humidity sensor was analyzed in combination with a bi-exponential kinetic adsorption ***,the potential application of ND/Ti_(3)C_(2)MXene composite-coated QCM humidity sensor was demonstrated through its frequency response to wooden blocks with different moisture contents.

关键词： Humidity sensor Quartz crystal microbalance Nanodiamond Ti_(3)C_(2)MXene High quality factor

Broadening environmental research in the era of accurate protein structure determination and predictions

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Frontiers of Environmental Science & Engineering 2024年第7期18卷 169-178页

作者： Mingda Zhou Tong Wang Ke Xu Han Wang Zibin Li wei-xian Zhang Yayi Wang State Key Laboratory of Pollution Control and Resources Reuse Shanghai Institute of Pollution Control and Ecological SecurityCollege of Environmental Science and EngineeringTongji UniversityShanghai 200092China Translational Research Institute of Brain and Brain-Like Intelligence Shanghai Fourth People's HospitalSchool of MedicineTongji UniversityShanghai 200434China

The deep-learning protein structure prediction method AlphaFold2 has garnered enormous attention beyond the realm of structural biology,for its groundbreaking contribution to solving the"protein foiding problem"In this perspective,we explore the connection between protein structure studies and environmental research,delving into the potential for addressing specific environmental *** are promising for environmental applications because of the functional diversity endowed by their structural ***,structural studies on proteins with environmental significance remain ***,we present the opportunity to study proteins by advancing experimental determination and deep-learning prediction ***,the latest progress in environmental research via cryogenic electron microscopy is *** allows us to determine the structure of protein complexes in their native state within cells at molecular resolution,revealing environmentally-associated structural *** the remarkable advancements in computational power and experimental resolution,the study of protein structure and dynamics has reached unprecedented depth and *** advancements will undoubtedly accelerate the establishment of comprehensive environmental protein structural and functional *** opportunities for protein engineering exist to enable innovative solutions for environmental applications,such as the degradation of persistent contaminants,and the recovery of valuable metals as well as rare earth elements.

关键词： Environmental proteins Protein structure Cryogenic electron microscopy Protein structure prediction Protein engineering Artificial Intelligence