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Feasibility Study of Anchored Fiber-Optic Strain-Sensing Arrays for Monitoring Soil Deformation beneath Model Foundation

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GEOTECHNICAL TESTING JOURNAL 2019年第4期42卷 966-984页

作者： Zhang, Cheng-Cheng Zhu, Hong-Hu Chen, Dong-Dong Xu, Xing-Yu Shi, Bin Chen, Xiao-Ping Nanjing Univ Sch Earth Sci & Engn 163 Xianlin Ave Nanjing 210023 Jiangsu Peoples R China Univ Calif Berkeley Dept Civil & Environm Engn Berkeley CA 94720 USA Jinan Univ Coll Sci & Engn MOE Key Lab Disaster Forecast & Control Engn 601 Huangpu Ave Guangzhou 510632 Guangdong Peoples R China

High-accuracy deformation measurement is an essential part of geotechnical model testing, in which fiber-optic sensors have great potentialities. In this study, a 1-g plane-strain model test was performed to investigate the feasibility of using fiber Bragg grating (FBG) strain-sensing arrays for monitoring soil deformation beneath a strip footing. The FBG array with specially made anchors was designed to enhance the fiber-soil interfacial bond and, hence, to improve the measurement quality. Three arrays were embedded horizontally within the soil to monitor internal linear strains, while digital photography-based particle image velocimetry (PIV) was employed to obtain superficial displacement and strain fields. Test results show that the strains captured by FBGs were comparable with equivalent strains determined via PIV analyses in terms of strain development, which reflected the evolution of soil deformation under incremental loads. Finally, the benefits and drawbacks of anchored FBG arrays for monitoring laboratory-scale models were discussed, with the conclusion being that they are capable of capturing internal strains or a strain profile of soil with low noise and high resolution, but there has to be a trade-off between robustness and sensitivity.

关键词： fiber Bragg grating strip footing strain measurement particle image velocimetry fiber-optic sensor

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The impact of biomass burning emissions in Southeast Asia on black carbon aerosols in southern China

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Atmospheric Environment 2025年 358卷

作者： Luhang Liu Yu-Hao Mao Hong Liao Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control/Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology School of Environmental Science and Engineering Nanjing University of Information Science and Technology (NUIST) Nanjing 210044 China Key Laboratory of Meteorological Disaster Ministry of Education (KLME)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD)/International Joint Research Laboratory on Climate and Environment Change (ILCEC) NUIST Nanjing 210044 China

Since 2013, China's air quality has significantly improved due to the reduction of anthropogenic emissions. The influence of long-distance transport of biomass burning emissions in Southeast Asia (BBSEA) on air quality in southern China (SC) would likely continue to increase, especially under the trend of global warming. We quantify the contribution of BBSEA to the surface and high-altitude BC concentrations in SC (two provincial capitals: Guangzhou (GZ), Guangdong, and Kunming (KM), Yunnan) in March–April 2014 and 2019 by using the GEOS-Chem global chemical transport model and its adjoint. For three severe pollution events in SC in 2014, the contributions of BBSEA to daily average BC concentrations in GZ are 0.08–0.19 μg m −3 (2 %–5 %) at the surface and 0.20–0.78 μg m −3 (59 %–73 %) at 700 hPa. In KM, the corresponding contributions are 0.27–0.54 μg m −3 (15 %–33 %) and 0.25–0.45 μg m −3 (28 %–45 %). The transport time of BBSEA to the surface of GZ (KM) is about 3–6 days (1–5 days). The shift in wind fields from southwest to west and stronger wind speeds in April likely shorten the transport time of BBSEA to SC. On March 27, 2019, the relative contributions of BBSEA to the surface BC concentrations increase by 10 % in GZ and 14 % in KM, compared to March 23, 2014. Our study would offer scientific support for understanding BC sources and potential improvement of air quality in SC.

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Prediction Model and Experimental Study on Braking Distance under Emergency Braking with Heavy Load of Escalator

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MATHEMATICAL PROBLEMS IN engineering 2020年第1期2020卷

作者： Li, Zhongxing Ma, Haixia Xu, Peng Peng, Qifeng Huang, Guojian Liu, Yingjie Guangzhou Acad Special Equipment Inspect & Testin Guangzhou 510180 Peoples R China South China Univ Technol Guangzhou Coll Guangzhou 510800 Peoples R China Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China

In order to study the relationship between the braking distance and the load of escalator and realize the prediction of the rated load braking distance with a little load, the method of combining theoretical analysis and experimental research is used. First, the dynamic characteristics of the escalator during emergency braking are analyzed, and the prediction model of the braking distance of the escalator under different loads is derived based on the law of conservation of energy. Furthermore, the influence coefficients under different loads were determined through experimental studies, the model was revised, and the concept of equivalent no-load kinetic energy (ENKE) was proposed. The research shows that the braking distance of the escalator increases nonlinearly with the increase in load. When the no-load braking distance and the 25% rated load braking distance change greatly, the braking distance increases faster as the load increases;the escalators with large brake force have a small ENKE and are easy to stop. Otherwise, it is difficult to stop. The test results show that the comparison between the predicted value of the prediction model and the measured value has a maximum error of 2.7%, and the maximum error at rated load is only 2.0%, which fully meets the needs of engineering measurement. And the prediction method reduces test costs, enhances test security, and improves test coverage.

关键词： Kinetics

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TiB2- and Fe2P with nanotwins-reinforced Cu-based immiscible composites fabricated by selective laser melting: Formation mechanism and wear behavior

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JOURNAL OF ALLOYS AND COMPOUNDS 2021年 864卷

作者： Xie, Min Wu, Changyi Zhou, Shengfeng Jin, Jianbo Zhao, Shuzhen Chen, Dongchu Tiangong Univ Sch Mat Sci & Engn Tianjin 300387 Peoples R China Hunan First Normal Univ Dept Educ Sci Changsha 410205 Hunan Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China Jinan Univ Inst Adv Wear & Corros Resistance & Funct Mat Guangzhou 510632 Peoples R China Foshan Univ Sch Mat Sci & Energy Engn Foshan 52800 Guangdong Peoples R China

To restrain the collision and coarsening of Fe-rich droplets within supercooled Cu-Fe immiscible melt, the TiB2 particles as inoculants are introduced to produce the TiB2 and Fe2P with nanotwins-reinforced Cu-based immiscible composites by selective laser melting (SLM). The Cu-based immiscible composite with heterogeneous structure is characterized by nano-/micro-scale Fe2P particles and micron fibrous Fe2P dispersed within the epsilon-Cu matrix. Moreover, some nanotwinned Cu (nt-Cu) particles and a high density of nanotwins are embedded within these nano-scale Fe2P particles, whereas some irregular alpha-Fe precipitated within these fibrous Fe2P. The addition of TiB2 particles can refine the size of Fe2P and promote their homogeneous distribution within the epsilon-Cu matrix. As a result, the hardness and wear resistance of the TiB2 reinforced Cu-based immiscible composite are significantly improved by the combined strengthening mechanisms of twin boundaries (TBs) strengthening, refinement strengthening, dispersion strengthening and precipitation strengthening. (C) 2021 Elsevier B.V. All rights reserved.

关键词： Selective laser melting Immiscible composite Wear behavior Liquid phase separation Nanoscale twins

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Hybrid three-dimensional graphene fillers and graphite platelets to improve the thermal conductivity and wear performance of epoxy composites

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COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING 2019年 123卷 270-277页

作者： Zhou, Helezi Wang, Hongjian Du, Xusheng Mo, Youtian Yuan, Hong Liu, Hong-Yuan Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China Jinan Univ Inst Adv Wear & Corros Resistant & Funct Mat Guangzhou 510632 Guangdong Peoples R China Univ Sydney Sch Aerosp Mech & Mechatron Engn J07 Sydney NSW 2006 Australia

Based on our recent work on the three-dimensional graphene fillers (3DGF) reinforced epoxy (EP) composite, here commercially available graphite platelets (GP) were incorporated together with 3DGF to modify EP in order to further improve the thermal conduction and wear resistance of the EP composites. Remarkably, only 0.14 vol % 3DGF was needed to enhance the thermal conduction of EP by 170%, in contrast with the fact that 37 times content of graphite fillers were required to achieve almost the same enhancement. Moreover, in the presence of both 5.38 vol% GP and 0.14 vol% 3DGF, the thermal conductivity of EP was further enhanced by 258%. Meanwhile, the tribological test results revealed the advantage of 3DGF over GP. The ternary EP composite modified with both 0.28 vol% of 3DGF and 5.38 vol% GP had much lower specific wear rate and coefficient of friction than those binary composites with either 3DGF or GP.

关键词： Hybrid Nanocomposites Thermal properties Wear

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Experimental study on flexural behavior of precast concrete beams in-span joined with UHPC

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Journal of Building engineering 2025年 111卷

作者： Zijun Xu Wei Zhou Guoyang Lu School of Civil Engineering Harbin Institute of Technology Harbin 150090 China Department of Architecture and Civil Engineering City University of Hong Kong Tat Chee Avenue Kowloon Tong Hong Kong Special Administrative Region of China Key Lab of Structures Dynamic Behavior and Control Ministry of Education Harbin Institute of Technology Harbin 150090 China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disaster Ministry of Industry and Information Technology Harbin Institute of Technology Harbin 150090 China

Efficient connection design is critical for the performance and applicability of precast concrete structures. This study proposes a novel in-span connection strategy using Ultra High Performance Concrete (UHPC) to assemble two standardized short precast concrete beams into a single unit, referred to as a Precast Beam Unit (PBU). This configuration relocates the joint from the beam ends to the mid-span, reducing local weakening and premature failure in high-stress regions while enhancing constructability. Static loading tests were conducted on five PBUs, with one cast-in-place beam serving as a control. The reinforcement ratio and the length of the UHPC corresponding to the diameter of the steel bar were employed as the main design parameters. The flexural behavior and failure mode of specimens were analyzed based on load displacement curves, crack propagation, and strain responses. Results showed that PBU-1 exhibited a 6.3 % higher ultimate flexural capacity than the cast-in-place beam. PBU-5, with a reinforcement ratio of 1.65 % demonstrated a 140.2 % higher ultimate bearing capacity compared to PBU-1 (0.64 % reinforcement ratio). PBUs also showed reduced deflection, narrower crack widths, and enhanced stiffness. The study proposed calculation methods for cracking analysis, short-term stiffness, and the normal section flexural capacity of PBU. Moreover, a finite element model developed in ABAQUS was employed to verify the damage situation and ultimate bearing capacity of the specimens, with good agreement with the experimental results. These findings confirm the safety and applicability of PBU and demonstrate its favorable connection performance.

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Experimental study of seismic performance of full-scale basalt FRP-recycled aggregate concrete-steel tubular columns

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THIN-WALLED STRUCTURES 2020年 151卷

作者： Zeng, Lan Li, Lijuan Xiao, Peijie Zeng, Junjie Liu, Feng Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China Guangdong Univ Technol Sch Civil & Transportat Engn Guangzhou 510006 Peoples R China Guangdong Planning & Designing Inst Telecommun Co Guangzhou 510630 Guangdong Peoples R China

Hybrid fiber-reinforced polymer (FRP)-concrete-steel double-skin tubular columns (DSTCs) have received extensive attention in the research community over the past decade. Generally, a DSTC consists of an inner steel tube and an outer FRP tube, with the space between them filled with natural aggregate concrete (NAC). This paper studied a new form of hybrid FRP-recycled aggregate concrete (RAC)-steel tubular column (FRSTC) in which the outer FRP tube was made of environmental-friendly basalt fibers and the concrete was made of recycled coarse aggregates (RCAs). Quasi-static tests of five full-scale basalt FRSTCs were conducted to gain an improved understanding of the behavior of FRSTCs, and to enable further application potentiality of FRSTCs in earthquake-prone areas. Three key column parameters, including RCA replacement percentages, axial load ratios, and steel reinforcement ratios were carefully designed to clarify their influence on the performance of FRSTCs under combined axial compression and cyclic lateral loading. The test results, including the hysteretic loops, skeleton curves, curvature and strain distributions, ductility characterization, energy dissipation capacity, stiffness and strength degradation, and cumulative damage, are presented and discussed. The experimental results show that the RCA replacement percentage has little impact on the seismic performance of FRSTCs, while the effect of the axial load ratio is significant. The bearing capacity and energy dissipation of FRSTCs can be superior to those of DSTCs with NAC.

关键词： Basalt fiber-reinforced polymer (BFRP) tube Recycled aggregate concrete (RAC) Steel tube Composite column Seismic behavior Quasi-static test

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EXPERIMENTAL STUDY ON MECHANICAL PROPERTIES OF POLYURETHANE POWDER COMPOSITES

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CIVIL engineering JOURNAL-STAVEBNI OBZOR 2021年第4期30卷 877-888页

作者： Zhang, Kexin Li, Dachao Shen, Xinyuan Xue, Xingwei Gu, Dandan Jinan Univ MOE Key Lab Disaster Forecast & Control Engn 601 Huangpu Dadao West Guangzhou Guangdong Peoples R China Shenyang Jianzhu Univ Sch Traff Engn Dept Bridge 25 Hunnan Middle Rd Shenyang Peoples R China Shenyang Inst Technol Sch Energy & Hydraul Engn East Sect Binhe Rd Shenfu New Dist Liaoning Peoples R China

In recent years, there have been cases of strengthening bridge structures with polyurethane cement mortar. To further explore the properties of polyurethane materials, the effects of emery, lime, quartz sand and cement on the mechanical properties of polyurethane powder composites are studied by three-point flexural test. In the flexural test, the polyurethane cement composite formed a control group by changing the content of polyester polyol. The flexural strength and ductility are improved to a certain extent due to the addition of polyester polyol. The average flexural strength of other polyurethane powder composites such as polyurethane emery test block is 45.1 MPa and the corresponding strain is 6203 mu epsilon, the average flexural strength of polyurethane lime test block is 33.4 MPa and the corresponding strain is 6470 mu epsilon, the average flexural strength of polyurethane quartz sand test block is 49.23 MPa and the corresponding strain is 7521 mu epsilon. The results show that the flexural strength of polyurethane emery material and polyurethane quartz sand material is higher than that of polyurethane cement, which can be used to replace cement to a certain extent to reduce the cost of polyurethane composite material.

关键词： Polyurethane cement (PUC) material Mechanics performance tests Polyurethane powder composites Constitutive relation

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Abrupt emissions reductions during COVID-19 contributed to record summer rainfall in China (vol 13, pg 1, 2022)

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NATURE COMMUNICATIONS 2022年第1期13卷 1-7页

作者： Yang, Yang Ren, Lili Wu, Mingxuan Wang, Hailong Song, Fengfei Leung, L. Ruby Hao, Xin Li, Jiandong Chen, Lei Li, Huimin Zeng, Liangying Zhou, Yang Wang, Pinya Liao, Hong Wang, Jing Zhou, Zhen-Qiang Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology School of Environmental Science and Engineering Nanjing University of Information Science and Technology Nanjing Jiangsu China Atmospheric Sciences and Global Change Division Pacific Northwest National Laboratory Richland WA USA Frontier Science Centre for Deep Ocean Multispheres and Earth System and Physical Oceanography Laboratory Ocean University of China Qingdao China Qingdao National Laboratory for Marine Science and Technology (QNLM) Qingdao China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster Ministry of Education Nanjing University for Information Science and Technology Nanjing Jiangsu China Tianjin Key Laboratory for Oceanic Meteorology Tianjin Institute of Meteorological Science Tianjin China Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan University Shanghai China

Record rainfall and severe flooding struck eastern China in the summer of 2020. The extreme summer rainfall occurred during the COVID-19 pandemic, which started in China in early 2020 and spread rapidly across the globe. By disrupting human activities, substantial reductions in anthropogenic emissions of greenhouse gases and aerosols might have affected regional precipitation in many ways. Here, we investigate such connections and show that the abrupt emissions reductions during the pandemic strengthened the summer atmospheric convection over eastern China, resulting in a positive sea level pressure anomaly over northwestern Pacific Ocean. The latter enhanced moisture convergence to eastern China and further intensified rainfall in that region. Modeling experiments show that the reduction in aerosols had a stronger impact on precipitation than the decrease of greenhouse gases did. We conclude that through abrupt emissions reductions, the COVID-19 pandemic contributed importantly to the 2020 extreme summer rainfall in eastern China.

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Gas Drainage Methods and Developing Direction of Gob

Gas Drainage Methods and Developing Direction of Gob

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作者： YAN Bao-yong CAO Liu Chongqing Research Institute of China Coal Technology and Engineering Group State Key Lab. of Gas Disaster Monitoring and Control as well as Emergency Technology Southwest Petroleum University

In the coal mine gas drainage,the gas drainage in gob has a dominant position. According to different stages of the production,the mining areas are divided into the gob,the old one and the abandoned one. Gas drainage of gob has an important influence on mining propulsion. Through comparative analysis of various drainage methods,exclusive tunnel pumping method will gradually be eliminated with the promotion of directional drilling technique in the roof construction and application. Large diameter roof horizontal directional long drill hole will replace the roof pumping lane,the roof short drilling,and gob buried drainage pipe. Some old gob has begun experiments of ground wells. A well used repeatedly can maximize the drainage of gas in the future,along with one-well three-purpose technology continues to be mature. The true sense of the abandoned mine gas drainage is still blank in China,according to the experience of foreign pumping,the ground large diameter bored construction will become a reasonable choice in obsolete mine gob gas drainage.

关键词： gob gas drainage ground borehole

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