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Pressurized environments directly influence friction and wear of dry steel contacts—Investigations in a novel high fluid pressure tribometer

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Friction 2024年第7期12卷 1599-1617页

作者： Paul REICHLE Jakob BARZ Georg UMLAUF Günter E.M.TOVAR institute of interfacial process engineering and plasma technology(IGVP) University of StuttgartStuttgart 70569Germany Fraunhofer institute for interfacial engineering and Biotechnology(IGB) Stuttgart 70569Germany

To reduce the usage of classical lubricants in deep drawing,a new tribological system based on volatile lubricants was ***,a volatile medium is injected under high pressure into the interstice between drawing tool and sheet *** on temperature and pressure,the temporary lubricant may exist in its gaseous or liquid *** this study,a novel high fluid pressure tribometer was designed to investigate the friction and wear of dry steel contacts under comparable conditions like in dry deep ***,a new ball-on-disc tribometer was designed and integrated into a high-pressure *** specifically investigate the effects of different environments(technical air,liquid and gaseous carbon dioxide,nitrogen,argon)at atmospheric and high pressure(0.1 MPa,6 MPa)on tribology,the specimens and all components were operating *** the experiments,the friction was measured *** show that the highest friction occurs in air and the lowest in carbon dioxide *** to the experiments,the wear of the specimens was assessed along with changes in surface chemistry related to tribochemical ***,the tribology of the dry sliding contacts is correlated to changes of the surface *** differences as well as similarities regarding the different fluid environments are *** the results show,the differences between the media used are most pronounced at elevated ***,this work gives clear indications on the suitability of volatile lubricants in dry friction or rather gas lubrication,especially for dry deep drawing.

关键词： dry friction and dry wear gas lubrication carbon dioxide tribo-layer dry metal forming

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Application of surfactant for improving leaching process of weathered crust elution-deposited rare earth ores

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Journal of Rare Earths 2024年第1期42卷 181-190,I0007页

作者： Fang Zhou Lisen Zhang Zhiwei Wang Yixin Zhang Ru'an Chi Xiaoyan Wu Key Laboratory for Green Chemical process of Ministry of Education Wuhan Institute of TechnologyWuhan430073China

Weathered crust elution-deposited rare earth ores(WREOs)in China are the main source of medium and heavy rare earths in the *** order to improve the seepage and the mass transfer of traditional ammonium salt leaching process of WREOs,surfactants were added in the ammonium sulfate leaching solution and the ammonium chloride leaching *** leaching kinetics,the mass transfer process,and the adhesion work reduction factor calculated from the interfacial properties were studied to reveal the strengthening mechanism of *** the presence of the tested five surfactants,cetyl trimethyl ammonium bromide(CTAB),dodecyl trimethyl ammonium bromide(DTAB),sodium dodecyl sulfate(SDS),sodium oleate and oleic acid,the permeability of WREOs is improved,the rare earth(RE)leaching efficiency increase and the impurity aluminum(Al)leaching efficiency decrease,indicating its promotional effect on the leaching process of ***,CTAB shows a better leaching enhancement,and the optimal addition dosage is 0.4 g/L for the two ammonium salt leaching agent *** kinetics analysis shows the internal diffusion controls model of RE and Al leaching process,and the leaching kinetics equations of RE and Al related to CTAB concentration were obtained for the two ammonium salt leaching *** to the chromatographic plate theory,the mass transfer efficiency of RE increases with the CTAB concentration increasing until 0.4 g/L,which confirms that the optimal CTAB addition is 0.4 g/*** adhesion work and adhesion work reduction factor indicate more favorable permeation as well as the leaching process.

关键词： Weathered crust elution-deposited rare earth ores Surfactant Kinetics Mass transfer

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A projected Newton algorithm based on chemically allowed interval for chemical equilibrium computations

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Frontiers of Chemical Science and engineering 2024年第3期18卷 25-37页

作者： Hongbin Lu Shaohui Tao Xiaoyan Sun Li Xia Shuguang Xiang institute of process Systems engineering College of Chemical EngineeringQingdao University of Science and TechnologyQingdao266042China

The chemical equilibrium equations utilized in reactive transport modeling are complex and nonlinear,and are typically solved using the Newton-Raphson *** this algorithm is known for its quadratic convergence near the solution,it is less effective far from the solution,especially for ill-conditioned *** such cases,the algorithm may fail to converge or require excessive *** address these limitations,a projected Newton method is introduced to incorporate the concept of *** method constrains the Newton step by utilizing a chemically allowed interval that generates feasible descending ***,we utilize the positive continuous fraction method as a preconditioning technique,providing reliable initial values for solving the *** numerical results are compared with those derived using the regular Newton-Raphson method,the Newton-Raphson method based on chemically allowed interval updating rules,and the bounded variable least squares method in six different test *** numerical results highlight the robustness and efficacy of the proposed algorithm.

关键词： chemical equilibrium reactive transport modeling numerical methods projected Newton method

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Phase equilibrium data prediction and process optimizationin butadiene extraction process

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Chinese Journal of Chemical engineering 2024年第7期71卷 1-12页

作者： Baowei Niu Yanjie Yi Yuwen Wei Fuzhen Zhang Lili Wang Li Xia Xiaoyan Sun Shuguang Xiang institute of process System engineering College of Chemical EngineeringQingdao University of Science and TechnologyQingdao 266042China

In response to the lack of reliable physical parameters in the process simulation of the butadiene extraction,a large amount of phase equilibrium data were collected in the context of the actual process of butadiene production by *** accuracy of five prediction methods,UNIFAC(UNIQUAC Functional-group Activity Coefficients),UNIFAC-LL,UNIFAC-LBY,UNIFAC-DMD and COSMO-RS,applied to the butadiene extraction process was verified using partial phase equilibrium *** results showed that the UNIFAC-DMD method had the highest accuracy in predicting phase equilibrium data for the missing ***-RS-predicted multiple systems showed good accuracy,and a large number of missing phase equilibrium data were estimated using the UNIFAC-DMD method and COSMO-RS *** predicted phase equilibrium data were checked for *** NRTL-RK(non-Random Two Liquid-Redlich-Kwong Equation of State)and UNIQUAC thermodynamic models were used to correlate the phase equilibrium *** device simulations were used to verify the accuracy of the thermodynamic model applied to the butadiene extraction *** simulation results showed that the average deviations of the simulated results using the correlated thermodynamic model from the actual values were less than 2%compared to that using the commercial simulation software,Aspen Plus and its *** average deviation was much smaller than that of the simulations using the Aspen Plus database(>10%),indicating that the obtained phase equilibrium data are highly accurate and *** best phase equilibrium data and thermodynamic model parameters for butadiene extraction are *** improves the accuracy and reliability of the design,optimization and control of the process,and provides a basis and guarantee for developing a more environmentally friendly and economical butadiene extraction process.

关键词： Butadiene extraction Phase equilibrium data Prediction methods Thermodynamic modeling process simulation

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Long‐life lithium batteries enabled by a pseudo‐oversaturated electrolyte

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Carbon Energy 2024年第4期6卷 115-127页

作者： Youchun Yu Simeng Wang Juyan Zhang Weiwei Qian Nana Zhang Guangjie Shao Haiyan Bian Yuwen Liu Lan Zhang Hebei Key Laboratory of Applied Chemistry College of Environmental and Chemical EngineeringYanshan UniversityQinhuangdaoChina Beijing Key Laboratory of Ionic Liquids Clean process CAS Key Laboratory of Green Process and EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijingChina Haike Group Research institute of Innovation&technology DongyingChina Langfang Green Industrial technology Center LangfangChina

The specific energy of Li metal batteries(LMBs)can be improved by using high‐voltage cathode materials;however,achieving long‐term stable cycling performance in the corresponding system is particularly challenging for the liquid ***,a novel pseudo‐oversaturated electrolyte(POSE)is prepared by introducing 1,1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropyl ether(TTE)to adjust the coordination structure between diglyme(G2)and lithium bis(trifluoromethanesulfonyl)imide(LiTFSI).Surprisingly,although TTE shows little solubility to LiTFSI,the molar ratio between LiTFSI and G2 in the POSE can be increased to 1:1,which is much higher than that of the saturation state,1:*** and experimental results prove that TTE promotes closer contact of the G2 molecular with Li^(+)in the ***,it also participates in the formation of electrolyte/electrode *** electrolyte shows outstanding compatibility with both the Li metal anode and typical high‐voltage ***||Li symmetric cells show a long life of more than 2000 h at 1 mA cm^(−2),1 mAh cm^(−2).In the meantime,Li||LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)cell with the POSE shows a high reversible capacity of 134.8 mAh g^(−1 )after 900 cycles at 4.5 V,1 C *** concept of POSE can provide new insight into the Li^(+)solvation structure and in the design of advanced electrolytes for LMBs.

关键词： high voltage lithium metal batteries pseudo‐oversaturated electrolyte solid electrolyte interphases(SEI) solvation structure

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Selective cyclohexane oxidation enhancement by electronic structures regulation of metal-poly(ionic liquid)s

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Green Chemical engineering 2024年第2期5卷 213-221页

作者： Ying Jin Shengxin Chen Ruirui Wang Yumei Liu Xinxin Li Yingwei Li Ruirui Zhang Ruixia Liu Henan institute of Advanced technology Zhengzhou UniversityZhengzhou450001China Beijing Key Laboratory of Ionic Liquids Clean process CAS Key Laboratory of Green Process and EngineeringState Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringInnovation Academy for Green ManufactureCASBeijing100190China

Poly(ionic liquids)(PILs)combined with the macromolecular structure and unique properties of ionic liquids show unlimited potential in *** this work,a series of metal-based PIL with different ionic ratios were prepared for the selective oxidation of *** analysis reveals that different degrees of ionization could adjust the Co-N sites of the catalysts efficiently,leading to significant changes in their electronic structure,which strongly relate to catalytic performance in oxidation.20.07%cyclohexane conversion and 13.06%cyclohexanone and cyclohexanol(KA oil)yield can be achieved by metal-based PILs that are better than other commercial *** with CoCl_(2),metal-based PILs perform well,with superior conversion and KA oil *** interestingly,the catalyst created in this study features a malleable Co-N site,which may potentially have an impact on how oxygen species adsorb and desorb from the ***,the catalyst studied in this work is used as molecular oxygen for the selective oxidation of cyclohexane to produce KA oil,and its application prospect is promising.

关键词： Metal-PILs Cyclohexane oxidation C-H activation Co-N sites

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An improved analysis method for assessing the nuclear-heating impact on the stability of toroidal field magnets in fusion reactors

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Nuclear Science and Techniques 2024年第6期35卷 163-176页

作者： Yu-Dong Lu Jin-Xing Zheng Xu-Feng Liu Huan Wu Jian Ge Kun Xu Ming Li Hai-Yang Liu Lei Zhu Fei Liu institute of plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China University of Science and technology of China Hefei 230026China

The superconducting magnet system of a fusion reactor plays a vital role in plasma confinement,a process that can be dis-rupted by various operational factors.A critical parameter for evaluating the temperature margin of superconducting magnets during normal operation is the nuclear heating caused by D-T *** study investigates the impact of nuclear heat-ing on a superconducting magnet system by employing an improved analysis method that combines neutronics and thermal *** the magnet system,toroidal field(TF)magnets are positioned closest to the plasma and bear the highest nuclear-heat load,making them prime candidates for evaluating the influence of nuclear heating on *** enhance the modeling accuracy and facilitate design modifications,a parametric TF model that incorporates heterogeneity is established to expedite the optimization design process and enhance the accuracy of the computations.A comparative analysis with a homogeneous TF model reveals that the heterogeneous model improves accuracy by over 12%.Considering factors such as heat load,magnetic-field strength,and cooling conditions,the cooling circuit facing the most severe conditions is selected to calculate the temperature of the *** selection streamlines the workload associated with thermal-hydraulic *** approach enables a more efficient and precise evaluation of the temperature margin of TF ***,it offers insights that can guide the optimization of both the structure and cooling strategy of superconducting magnet systems.

关键词： Superconducting magnet Nuclear heating Neutronics Thermal hydraulics

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Implementation and validation of a bonded particle model to predict rheological properties of viscoelastic materials

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Particuology 2024年第6期89卷 198-210页

作者： Michael Mascara Arno Mayrhofer Stefan Radl Christoph Kloss institute of process and Particle engineering Graz University of TechnologyInffeldgasse 13Graz8010Austria DCS Computing GmbH Industriezeile 35Linz4020Austria

This work focuses on implementing a particle-based method able to characterize viscoelastic materials whose rheological properties,such as storage modulus G′and loss modulus G″,are *** is based on the bonded particle model,with the elastic constitutive relation here substituted with a viscoelastic one to capture time-scale *** Burgers model,vastly used in literature to model viscoelastic systems,is discretized and *** test case used for calibration comprises of a cubic lattice,sheared with a periodic motion,to mimic the effect of a shear *** appropriate filtering of the stress response,the rheological properties are obtained,highlighting the effect of the lattice geometry,as well as the particle size,on the accuracy of the ***,the Burgers parameters are calibrated by analytically fitting the experimental dataset,showing the limitation of the Burgers *** micro-contact parameters are obtained from the macro parameters through appropriate *** completing a frequency sweep,the simulated G′and G″show a relatively large error,around 25%for G’for *** this reason,a more robust model,namely the generalized Maxwell model,has been *** calibration procedure is performed in the same fashion as for the Burgers ***,the tangential micro-contact parameters are scaled *** normal *** scaling parameter,calledα,is calibrated by minimizing the root mean square error between simulation and experimental data,giving errors below 10%in both G′and G″for a large ***,a full ring plate-plate rheometer setup is simulated,and the simulation is compared with the given experimental dataset,again finding a good agreement.

关键词： DEM Rheology Numerical modeling Viscoelasticity

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Multi-level coarse-grained discrete element method modeling of cylinder particle flow in a rotating drum

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Particuology 2024年第5期88卷 218-238页

作者： Lei Xu Xiukai Wu Shuai Wang Shiyi Bao institute of process Equipment and Control engineering Zhejiang University of TechnologyHangzhou 310023China engineering Research Center of process Equipment and Remanufacturing Ministry of EducationZhejiang University of TechnologyHangzhou 310023China College of Mechanical engineering Zhejiang University of TechnologyHangzhou 310023China State Key Laboratory of Clean Energy Utilization Zhejiang UniversityHangzhou 310027China

The coarse-grained discrete element method(DEM)is probably a feasible option for simulating an actual drum-type biomass boiler,which contains over 10 million cylinder particles.A multi-level study was conducted based on particle and coarse-grained level data to evaluate the adequacy of the coarse-grained approach in terms of geometrical characteristics,kinematic features,and dynamic *** scaling laws for contact parameters were used and compared during the *** results show that the coarse-grained approach can accurately predict the positions of the free surface and active-passive interface,the mixing index,and the orientation *** in the velocity fields may occur due to the worse flowability of coarse-grained particles near the free *** efficiency is significantly improved by the coarse-grained model compared with the corresponding original case(the same DEM code without a coarse-grained model was used for the original simulations).

关键词： Coarse-grained method Discrete element method(DEM) Cylinder particle Rotating drum Granular flow

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Large-area ultrastrong and stiff aramid nanofiber based layered nanocomposite films

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Nano Research 2024年第2期17卷 829-835页

作者： Zhidong Nie Yingzhi Sun Tianxu Zhou Shengwen Kong Linxing Liu Chuangqi Zhao Mingjie Liu Key Laboratory of Bioinspired Smart interfacial Science and technology of Ministry of Education School of ChemistryBeihang UniversityBeijing 100191China University of Science and technology of China Hefei 230026China Suzhou institute for Advanced Research University of Science and Technology of ChinaSuzhou 215123China International Research institute for Multidisciplinary Science Beihang UniversityBeijing 100191China

One-dimensional(1D)aramid nanofiber(ANF)based nanocomposite films have drawn increasing attentions in various applications due to their excellent mechanical properties and impressive chemical and thermal ***,the large-area fabrication of aramid nanocomposite films with ultrastrong mechanical properties under mild conditions remains a great *** we present a facile superspreading-assisted strategy to produce aramid nanofiber based oriented layered nanocomposites using phase inversion process that occurs at the fully swollen hydrogel *** nanocomposite films based on ANF,carboxylation carbon tube(CNT–COOH),poly(vinyl alcohol)(PVA),and MXene nanosheet exhibit a tensile strength of up to 870.8±85 MPa,a Young’s modulus of 21.8±2.2 GPa,and outstanding toughness(up to 43.2±4.6 MJ/m^(3)),which are much better than those conventional aramid nanofiber based *** conductivity of our nanocomposite films reaches the maximum of about 1100 S/*** fabulous mechanical properties combination and continuous production capability render our strategy representing a promising direction for the development of high-performance nanocomposites.

关键词： aramid nanofibers MXene nanosheets nanocomposites ultrastrong and stiff superspreading large-area production

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