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Effects of aggregate size distribution and carbon nanotubes on the mechanical properties of cemented gangue backfill samples under true triaxial compression

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 311-324页

作者： Qian Yin Fan Wen Zhigang Tao Hai Pu Tianci Deng Yaoyao Meng Qingbin Meng Hongwen Jing Bo Meng Jiangyu Wu State Key Laboratory of Intelligent Construction and Healthy Operation and maintenance of Deep Underground engineering China University of Mining and TechnologyXuzhou 221116China State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and TechnologyHuainan 232001China State Key Laboratory for Geomechanics&Deep Underground engineering China University of Mining and Technology(Beijing)Beijing 100083China Key Laboratory of Xinjiang Coal Resources Green Mining Ministry of EducationXinjiang Institute of EngineeringUrumqi 830023China

The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious ***,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of *** mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically *** results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,***,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the ***σ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite ***ε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse *** increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.

关键词： cemented gangue backfill materials particle size distribution true triaxial compression test carbon nanotubes mechanical properties failure modes

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Role of copper chelating agents: between old applications and new perspectives in neuroscience

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Neural Regeneration Research 2025年第3期20卷 751-762页

作者： Rosalba Leuci Leonardo Brunetti Vincenzo Tufarelli Marco Cerini Marco Paparella Nikola Puvača Luca Piemontese Department of Pharmacy-Pharmaceutical Science University of Bari Aldo MoroBariItaly Department of Precision and Regenerative Medicine and Jonian Area(DiMePRe-J) Section of Veterinary Science and Animal ProductionUniversity of Bari Aldo MoroBariItaly Department of engineering Management in Biotechnology Faculty of Economics and Engineering Management in Novi SadUniversity Business Academy in Novi SadNovi SadSerbia

The role of copper element has been an increasingly relevant topic in recent years in the fields of human and animal health, for both the study of new drugs and innovative food and feed supplements. This metal plays an important role in the central nervous system, where it is associated with glutamatergic signaling, and it is widely involved in inflammatory processes. Thus, diseases involving copper(Ⅱ) dyshomeostasis often have neurological symptoms, as exemplified by Alzheimer's and other diseases(such as Parkinson's and Wilson's diseases). Moreover, imbalanced copper ion concentrations have also been associated with diabetes and certain types of cancer, including glioma. In this paper, we propose a comprehensive overview of recent results that show the importance of these metal ions in several pathologies, mainly Alzheimer's disease, through the lens of the development and use of copper chelators as research compounds and potential therapeutics if included in multi-target hybrid drugs. Seeing how copper homeostasis is important for the well-being of animals as well as humans, we shortly describe the state of the art regarding the effects of copper and its chelators in agriculture, livestock rearing, and aquaculture, as ingredients for the formulation of feed supplements as well as to prevent the effects of pollution on animal productions.

关键词： agriculture Alzheimer's disease chelators copper feed supplements multi-target

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Fatigue Strength Analysis of Dissimilar Aluminum Alloy TIG Welds

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 265-274页

作者： LIAO Xiangyun WANG Ruijie LIU Guoshou ZHAO Pinglin Faculty of Mechanical and Electrical engineering Kunming University of Science and TechnologyKunming 650500China Faculty of Civil engineering and Mechanics Kunming University of Science and TechnologyKunming 650500China

The constant amplitude loading fatigue tests were carried out on the 6061/7075 aluminum alloy TIG fillet welded lap specimens in this study,and the weld seam cross-section hardness was *** experimental results show that most specimens mainly failed at the 7075 side weld toes even though the base material tensile strength of 7075 is higher than that of *** maximum stress-strain concentration in the two finite element models is located at the 7075 side weld toe,which is basically consistent with the actual fracture *** weld zone on the 7075 side experiences severe material softening,with a large ***,the Vickers hardness value on the 6061 side negligibly changes and fluctuates around 70 *** obvious defects are found on the fatigue fracture,but a large number of secondary cracks *** germinate from the weld toe and propagate in the direction of the plate *** reinforcement has a serious impact on fatigue *** life will decrease exponentially as the weld reinforcement increases under low *** is found that the notch stress method can give a better fatigue life prediction for TIG weldments,and the errors of the predicted results are within the range of two factors,while the prediction accuracy decreases under low *** equivalent structural stress method can also be used for fatigue life prediction of TIG weldments,but the errors of prediction results are within the range of three factors,and the accuracy decreases under high stress.

关键词： TIG welding notch stress method equivalent structural stress method fatigue life finite element analysis

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Mine production index(MPI)-extension of OEE for bottleneck detection in mining

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International Journal of Mining Science and Technology 2016年第5期26卷 753-760页

作者： Amol Arun Lanke Seyed Hadi Hoseinie Behzad Ghodrati Division of Operation and maintenance engineering Lule? University of Technology

Although mining production depends on various equipments, significant amount of production loss can be attributed a specific equipment or fleet. Bottleneck is defined not only by production loss but also by our satisfaction from the equipment. The user satisfaction could be measured as machine *** literatures on performance improvement and optimization of equipment operations assert importance of availability, utilization and production performance as key parameters. These three parameters are useful for evaluating effectiveness of equipment. Mine production index(MPI), which can represent the effect of these factors, has been applied for continuous operation in mining. MPI uses Fuzzy Delphi Analytical Hierarchy Process to determine importance of each three parameter for individual equipment. A case study in a Swedish open pit mine was done to evaluate the field application of *** results reveal that crusher is the bottleneck equipment in studied mine. As a methodical approach,an algorithm which uses MPI and detects bottleneck in continuous mining operation has been proposed.

关键词： Mine production index Bottleneck seeking FDAHP Production analysis

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Softw are Maintainability Evaluation Based on Quantitive Model

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Journal of Donghua University(English Edition) 2015年第1期32卷 154-156页

作者：郝学良王毅刚刘丽 maintenance engineering Institute Mechanical Engineering College

Software maintainability is one of the most important factors of software quality,but it is seriously difficult to evaluate the maintainability. Without evaluation,it is impossible to control. To estimate software maintainability state,parameter system of software was built up and maintainability state was defined into three *** of application on maintainability evaluation based on hidden Markov chain( HMC) and fuzzy inference was ***-state maintainability estimation model was constructed. To testify the feasibility of the model, a real example of software maintenance activity was carried out and the result from the example validated that the results of this study were applicable.

关键词： software maintainability hidden Markov chain(HMC) model fuzzy inference evaluation model

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Fouling corrosion in aluminum heat exchangers

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Chinese Journal of Aeronautics 2015年第3期28卷 954-960页

作者： Su Jingxin Ma Minyu Wang Tianjing Guo Xiaomei Hou Liguo Wang Zhiping Tianjin Key Laboratory for Civil Aircraft Airworthiness and maintenance Civil Aviation University of China Aircraft maintenance and engineering Corporation Beijing Capital International Airport

Abstract Fouling deposits on aluminum heat exchanger reduce the heat transfer efficiency and cause corrosion to the apparatus. This study focuses on the corrosive behavior of aluminum cou- pons covered with a layer of artificial fouling in a humid atmosphere by their weight loss, Tafel plots, electrochemical impedance spectroscopy （EIS）, and scanning electron microscope （SEM） observations. The results reveal that chloride is one of the major elements found in the fouling which damages the passive film and initiates corrosion. The galvanic corrosion between the metal and the adjacent carbon particles accelerates the corrosive process. Furthermore, the black carbon favors the moisture uptake, and gives the dissolved oxygen greater chance to migrate through the fouling layer and form a continuous diffusive path. The corrosion rate decreasing over time is conformed to electrochemistry measurements and can be verified by Faraday＇s law. The EIS results indicate that the mechanism of corrosion can be interpreted by the pitting corrosion evolution mechanism, and that pitting was observed on the coupons by SEM after corrosive exposure.

关键词： Aluminum EIS Heat exchanger Pitting corrosion Tafel plots

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Moment Redistribution Effect of the Continuous Glass Fiber Reinforced Polymer-Concrete Composite Slabs Based on Static Loading Experiment

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Structural Durability & Health Monitoring 2025年第1期19卷 105-123页

作者： Zhao-Jun Zhang Wen-Wei Wang Jing-Shui Zhen Bo-Cheng Li De-Cheng Cai Yang-Yang Du Hui Huang Offshore Oil engineering Co.Ltd. Tianjin300461China Department of Bridge engineering School of TransportationSoutheast UniversityNanjing211189China

This study aimed to investigate the moment redistribution in continuous glass fiber reinforced polymer(GFRP)-concrete composite slabs caused by concrete cracking and steel bar yielding in the negative bending moment *** experimental bending moment redistribution test was conducted on continuous GFRP-concrete composite slabs,and a calculation method based on the conjugate beam method was *** composite slabs were formed by combining GFRP profiles with a concrete layer and supported on steel beams to create two-span continuous composite slab *** methods,epoxy resin bonding,and stud connection,were used to connect the composite slabs with the steel *** experimental findings showed that the specimen connected with epoxy resin exhibited two moments redistribution phenomena during the loading process:concrete cracking and steel bar yielding at the internal *** contrast,the composite slab connected with steel beams by studs exhibited only one-moment redistribution phenomenon throughout the loading *** the concrete at the internal support cracked,the bending moment decreased in the internal support section and increased in the midspan *** the steel bars yielded,the bending moment further decreased in the internal support section and increased in the mid-span *** GFRP profiles do not experience cracking,there was no significant decrease in the bending moment of the mid-span *** test specimens experienced compressive failure of concrete at the mid-span *** results showed good agreement between the calculated and experimental values of bending moments in the mid-span section and internal support *** proposed model can effectively predict the moment redistribution behavior of continuous GFRP-concrete composite slabs.

关键词： Moment redistribution GFRP-concrete composite slabs bending moment experimental study analysis model

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Beam-track interaction of high-speed railway bridge with ballast track

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Journal of Central South University 2012年第5期19卷 1447-1453页

作者：闫斌戴公连张华平 Department of Civil engineering Central South University maintenance Departments of Guangzhou Municipal engineering

Based on the construction bridge of Xiamen-Shenzhen high-speed railway(9-32 m simply-supported beam + 6×32 m continuous beam),the pier-beam-track finite element model,where the continuous beam of the ballast track and simply-supported beam are combined with each other,was *** laws of the track stress,the pier longitudinal stress and the beam-track relative displacement were *** results show that reducing the longitudinal resistance can effectively reduce the track stress and the pier stress of the continuous beam,and increase the beam-track relative *** the rigid pier stiffness of continuous beam can reduce the track braking stress,increase the pier longitudinal stress and reduce the beam-track relative displacement,Increasing the rigid pier stiffness of simply-supported beam can reduce the track braking stress,the rigid pier longitudinal stress and the beam-track relative displacement.

关键词： high-speed railway beam-track interaction ballast track rail longitudinal force continuous beam

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Running Temperature and Mechanical Stability of Grease as maintenance Parameters of Railway Bearings

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International Journal of Automation and computing 2010年第2期7卷 160-166页

作者： Jan Lundberg Aditya Parida Peter Sderholm Division of Operation and maintenance engineering Lule University of Technology

Spherical roller bearings in railway car wheels are critical components whose failure may have catastrophic consequences. The present study aims to analyse the mechanical stability of greases and temperature of bearings as indicators for condition-based bearing maintenance. The performed case study includes nine fully-formulated commercial greases examined in the wheel bearings of five ore cars operated in northern Scandinavia. The studied ore cars travelled a distance of about 300 000 km during a period of three years. Small samples of the greases were taken on eight occasions to test their mechanical stability. In addition, the temperatures of the bearings were continuously recorded. After the test period, the wear, electrical damage, and corrosion of the bearings were examined. One of the findings is that the shear stress of the grease at a certain shear velocity （the certain yieldstress （CEY） value） is a good maintenance indicator and is highly dependent on the grease type. The bearing＇s wear, electrical damage and corrosion also depend on the grease type. However, no oxidation of the greases was identified. The paper also outlines a systematic methodology to determine an overall maintenance indicator for railway roller bearings which is based on the field measurements.

关键词： maintenance mechanical stability railway roller bearings grease lubrication.

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The Negative Thermal Expansion Property of NdMnO_(3) Based on Pores Effect and Phase Transition

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 39-43页

作者：李玉成张扬 ZHANG Muqun DUAN Rong LIU Xiteng Department of Avionics engineering Aviation Maintenance NCO Academy of Air Force Engineering UniversityXinyang 464000China

A novel negative thermal expansion(NTE) material NdMnO_(3) was synthesized by solid-state method at 1 523 K. The crystal structure, phase transition, pores effect and negative expansion properties of NdMnO_(3) were investigated by variable temperature X-ray diffraction(XRD), scanning electron microscope(SEM) and variable temperature Raman spectra. The compound exhibits NTE properties in the orderly O' phase crystal structure. When the temperature is from 293 to 759 K, the ceramic NdMnO_(3) shows negative thermal expansion of-4.7×10^(-6)/K. As temperature increases, the ceramic NdMnO_(3) presents NTE property range from 759 to 1 007 K. The average linear expansion coefficient is-18.88×10^(-6)/K. The physical mechanism of NTE is discussed and clarified through experiments.

关键词： negative thermal expansion NdMnO_(3) pores effect phase transition

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