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Macro-microscopic dynamic characteristics of the ballast bed induced by the variation of moisture content

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Particuology 2024年第7期90卷 118-127页

作者： Shuchen Wang Longlong Fu Yongjia Qiu Haonan xi.Shunhua zhou Key Laboratory of Road and Traffic Engineering of the Ministry of Education Tongji UniversityShanghai 201804China Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety Tongji UniversityShanghai 201804China

Due to the excellent drainage performance of the ballast,exi.ting studies mainly focus on the dynamic response of ballast under field capacity or *** has rarely been paid to dynamic changes in moisture content and potential *** this article,we firstly conduct a model test to determine the variation of ballast moisture content under artificial *** that,a full-scale model test with cyclic loading is carried out to study the effect of moisture content variation on the macro-microscopic response of the ballast bed,where several wireless particle sensors are installed to obtain ballast motion characteristics at strategic *** results show that the moisture content increases gradually and stabilizes at a flat peak under rainfall,despite the excellent drainage performance of ballast *** halting rainfall,the moisture content drops back to field capacity,which indicates dynamic flowing surface water on ballast particles under *** flowing surface water brings changes to the original dynamic equilibrium of ballast bed:macroscopically,the deformation rate of stabilized ballast bed increases significantly,reaching a local peak under field capacity;microscopically,the x-and z-angular accelerations of the ballast show positive correlation with rainfall *** multiscale responses indicate that field capacity is a critical moisture content.

关键词： Railway ballast Flowing surface water Wireless particle sensor Multidimensional motion Full-scale model test

Influence of in situ formed spinel in bonding phase on mechanical properties and air permeability of magnesia-chrome porous purging materials

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Journal of Iron and Steel Research International 2024年第6期31卷 1459-1472页

作者： Yi An Hao Liu zhou-fu Wang Yan Ma xi.tang Wang The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina

Magnesia-chrome porous purging plugs are crucial functional components to remove inclusions and stabilize the flow field during iron and steel ***,practical applications of magnesia-chrome porous purging materials are stil hampered by the poor scouring resistance to molten steel and unstable air permeability owing to their low mechanical properties and uncontrollable pore ***,the particle-packing type magnesiachrome porous purging materials reinforced by in situ formed spinel were prepared using fused magnesia-chrome particles and Al powders as major raw *** results show that in situ formed spinel solid solutions in bonding phase led to the decreased median pore size and increased pore surface fractal dimension from the reactions between Al powders and magnesia-chrome particles and along with high-temperature sintering,bonding between magnesia-chrome particles and the resultant mechanical properties of materials were greatly ***,the results of air permeability tests and polynomial ftting indicated that the formation of spinel solid solutions was the main contributing factor for controllable air permeability,and pressure drop of porous purging materials was positively correlated with surface fractal dimension of ***,the as-prepared porous purging materials added with 6 wt.%Al powders obtained the maxi.um cold crushing strength(54.2 MPa)and hot modulus of rupture(12.9 MPa)with median pore size of 24.06μm and ftting non-Darcian permeability coefficient of 0.97×10^(-6)m.

关键词： Magnesia Chrome porous purging material Metallic Al-Spinel Mechanical strength Air permeability

Effects of hot deformation and in-situ ZrB2 particle on microstructure and tensile performance of AA7085 composite sheets

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Journal of Iron and Steel Research International 2024年第7期31卷 1778-1791页

作者： Jiang-jing Wu xi.zhou Kai Chuang Guan Yu-tao Zhao School of Material Science and Engineering Jiangsu UniversityZhenjiang 212013JiangsuChina

To provide a new idea to reduce anisotropy for sheets in the thickness direction by microstructure modification and,mean-while,maintain or even enhance tensile performance,the in-situ ZrB2 particle/AA7085 composite sheets with thicknesses of 1,2,3,and 6 mm were *** as-cast grain size was significantly refined by the heterogeneous nucleus of the ZrB2 *** microstructure results show that severe hot deformation converts as-cast disordered microstructure into a sequential microstructure by crushing the remanent phases and matrix into a fiber *** the solid solution and aging heat treatment,the composite sheets exhibit largely recrystallized grains compared with partially recrystallized grains in the matrix sheets,and weak or even free texture exi.ts in the *** grain size in the composite sheets decreases with the increase in thickness *** the thickness range of 1-3 mm,the composite sheets maintain a similar tensile per-formance as that in matrix sheets,while the strength and ductility in the 6-mm-thick composite sheet are improved.

关键词： Composite sheet Grain structure Texture Dislocation Strengthening

Effect of Mn Addition and Heat Treatment on the Corrosion Behaviour of Mg-Ag-Mn Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 665-677页

作者： You Lv Yupeng Zhang xi.Liu Zehua Dong xi.orong zhou xi.xi. Zhang Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Material Chemistry and Service FailureSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan430074China Hubei Engineering Research Centre for Biomaterials and Medical Protective Materials Huazhong University of Science and TechnologyWuhan430074China Corrosion and Protection Centre Department of MaterialsThe University of ManchesterManchesterM139PLUK

The high corrosion sensitivity and the potential bio-toxi.ity of Mg-Ag alloys limit their wide applications for the production of implanted devices. In the present work, Mn is added into the Mg-Ag alloy to optimize its corrosion behaviour. The corrosion behaviour of Mg-Ag-Mn alloys is investigated with the underlying microstructural factors examined. The Mg-Ag alloy with 2 wt% Mn exhibits the highest corrosion resistance after post-casting heat treatment at 440 ℃. The addition of Mn results in α-Mn phase with the incorporation of Fe, which suppresses the cathodic activity of impurity Fe. Further, heat treatment of the cast alloys homogenizes the distribution of Ag and promotes the precipitation of α-Mn phase. The former removes Ag segregations as potential cathodes;the latter promotes a more uniform distribution of cathodes and, therefore, prevents localized corrosion.

关键词： Mg-Ag alloy Mn addition Post-casting heat treatment Cathodic activity Corrosion mechanism

A comprehensive comparison of different regression techniques and nature-inspired optimization algorithms to predict carbonation depth of recycled aggregate concrete

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Frontiers of Structural and Civil Engineering 2024年第1期18卷 30-50页

作者： Bin xi.Ning ZHANG Enming LI Jiabin LI Jian zhou Pablo SEGARRA Department of Civil and Environmental Engineering Politecnico Di MilanoMilano 20133Italy Leibniz Institute of Ecological Urban and Regional Development(IOER) Dresden 01217Germany Universidad Politécnica de Madrid-ETSI Minas y Energía Madrid 28003Spain Department of Civil Engineering KU Leuven CampusBrugge 8200Belgium School of Resources and Safety Engineering Central South UniversityChangsha 410083China

The utilization of recycled aggregates(RA)for concrete production has the potential to offer substantial environmental and economic ***,RA concrete is plagued with considerable durability concerns,particularly *** advance the application of RA concrete,the establishment of a reliable model for predicting the carbonation is *** the one hand,concrete carbonation is a long and slow process and thus consumes a lot of time and energy to *** the other hand,carbonation is influenced by many factors and is hard to *** this,this paper proposes the use of machine learning techniques to establish accurate prediction models for the carbonation depth(CD)of RA *** types of regression techniques and meta-heuristic algorithms were employed to provide more alternative predictive *** was found that the best prediction performance was obtained from extreme gradient boosting-multi-universe optimizer(XGB-MVO)with R^(2) value of 0.9949 and 0.9398 for training and testing sets,***-MVO was used for evaluating physical laws of carbonation and it was found that the developed XGB-MVO model could provide reasonable predictions when new data were *** also showed better generalization capabilities when compared with different models in the ***,this paper emphasizes the need for sustainable solutions in the construction industry to reduce its environmental impact and contribute to sustainable and low-carbon economies.

关键词： recycled aggregate concrete carbonation depth nature-inspired optimization algorithms extreme gradient boosting technique parametric analysis

Efficacy and safety of Chinese herbal medicine as adjunctive therapy in sepsis patients with bloodstream infection:a propensity-matched analysis

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Journal of Traditional Chinese Medicine 2024年第1期44卷 197-204页

作者： zhou xi.nshi ZHONG Minlin xi.xi.otu LI Jun TANG Guanghua the Second Clinical College of Guangzhou University of Chinese Medicine Guangzhou 510120China Emergency Department Guangdong Provincial Hospital of Chinese MedicineGuangzhou 510120China Guangdong Provincial Key Laboratory of Research on Emergency in TCM Guangzhou 510120China Guangzhou Key Laboratory of Traditional Chinese Medicine for Prevention and Treatment of Emerging Infectious Diseases Guangzhou 510120China Administration Department the First Hospital of Guangzhou University of Chinese MedicineGuangzhou 510405China

OBJECTIVE:To investigate the efficacy and safety of Chinese herbal medicine in treating sepsis patients with bloodstream ***:A 6-year retrospective study was carried out at a university hospital in *** sepsis patients with bloodstream infection were *** primary outcome was 28-day mortality after *** score method was used to adjust for possible confounding.28-day mortality was estimated by KaplanMeier analysis and compared using the log-rank *** regression analysis was carried out to identify factors impacting in-hospital mortality ***:Following the application of the propensity score method,a total of 176 patients were *** all-cause 28-day mortality in the control group and Chinese herbal medicine group was 21.6%and 14.8%,***-Meier survival analysis showed that Chinese herbal medicine was associated with a lower hazard ratio(HR)in all-cause 28-day death compared with the control group[HR=0.44,95%CI(0.22,0.90),P0.05).Blood-activating and stasis-eliminating herb administration was associated with reduced inhospital mortality among sepsis patients with bloodstream infection[HR=0.54,95%CI(0.34,0.94),P<0.05].CONCLUSIONS:Chinese herbal medicine,especially the blood-activating and stasis-eliminating herb,might have certain efficacy and safety in treating sepsis patients with bloodstream *** should prescribe blood-activating and stasis-eliminating herb in treating these two coalescent critical diseases as long as no contraindications ***,further studies are needed to validate our results.

关键词： bacteremia medicine Chinese traditional herbal medicine sepsis propensity-matched analysis

Impacts of multi-foulings on salinity gradient energy conversion process in negatively charged conical nanochannels

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Science China(Technological Sciences) 2024年第6期67卷 1714-1726页

作者： MAO RuiJie CHEN xi.zhou RuHong LONG Rui LIU ZhiChun LIU Wei School of Energy and Power Engineering Huazhong University of Science and TechnologyWuhan430074China China-EU Institute for Clean and Renewable Energy Huazhong University of Science and TechnologyWuhan430074China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan430074China

Membrane fouling inevitably occurs during nanofluidic reverse ***,the impact of multi-fouling on the energy conversion performance of negatively charged conical nanochannels under asymmetrical configurations is systematically *** results reveal that in Configuration I,where a high-concentration solution is applied at the tip side,at small concentration ratios,multiple foulings reduce the electric *** Configuration II,where a low-concentration solution is applied at the tip side,multiple foulings near the base side contribute to the electric *** fouling that formed near the lowconcentration entrance diminished the electric power and energy conversion ***-fouling lowered the electrical power consumption by 69.27%and 99.94%in Configurations I and II,*** Configuration I,the electric power first increased with increasing fouling surface charge density,reached its maxi.um value,and thereafter *** Configuration II,the electric power first decreased with increasing fouling surface charge density,reached its minimum value,and thereafter *** negative or positive charge densities of fouling contribute to the electric power and energy conversion efficiency.

关键词： conical nanochannel fouling nanofluidic reverse electrodialysis salinity gradient energy

Liquid metal droplet dynamics

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Droplet 2024年第1期3卷 61-94页

作者： xi.Zhao Mengwen Qiao Yingxi. zhou Jing Liu Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijingChina School of Future Technology University of Chinese Academy of SciencesBeijingChina Department of Biomedical Engineering School of MedicineTsinghua UniversityBeijingChina

The unique properties to combine the dual merits of both liquids and metals together make the gallium‐based liquid metal(LM)droplets a class of unconventional substitute which possess great potential for a group of newly emerging areas,such as stretchable electronics,soft devices,micro sensors and *** addition,LM droplets are undoubtedly an intriguing target worth of pursuing in fundamental hydrodynamic investigations due to their extremely high surface tension nature compared to classical nonmetallic *** the discovery of the diverse transformation phenomena and self‐fueled droplet mollusks of LM that can move automatically in solution via single electricity or even without any external energy supply,tremendous attentions were attracted to this special fluidic object of LM *** the past decade,there has been a proliferation of explorations on LM droplet dynamics,while the involved contents are heterogeneous due to the interfacial physical/chemical activity of the LM and the diversity of the kinetic *** better understand and manipulate the droplet behavior and to promote further development of the LMs,this review is dedicated to summarize the latest progress and presents an overview on basic findings related to LM macrodroplet ***,the extended definition of LM droplets and the corresponding fabrication methods are ***,typical works on LM droplet dynamics are systematically interpreted based on their different behavior ***,the perspectives,main obstacles and challenges restricting the development of LM droplet dynamics are pointed out.

关键词： dynamics behavior doubt

A unified Minorization-Maxi.ization approach for estimation of general mixture models

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 343-362页

作者： HUANG xi.fen LIU Deng-ge zhou Yun-peng ZHU Fei School of Mathematics Yunnan Normal UniversityKunming 650092China Department of Statistics and Actuarial Science The University of Hong KongHong KongChina

The mixed distribution model is often used to extract information from heteroge-neous data and perform modeling *** the density function of mixed distribution is complicated or the variable dimension is high,it usually brings challenges to the parameter es-timation of the mixed distribution *** application of MM algorithm can avoid complex expectation calculations,and can also solve the problem of high-dimensional optimization by decomposing the objective *** this paper,MM algorithm is applied to the parameter estimation problem of mixed distribution *** method of assembly and decomposition is used to construct the substitute function with separable parameters,which avoids the problems of complex expectation calculations and the inversion of high-dimensional matrices.

关键词： MM algorithm mixed distribution model parameter estimation assembly decomposition tech-nology parameter separation