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SSRN 2024年

作者： Zhang, Haina Hu, Wenhui Li, Huan Chen, Shunman Xia, Kaizong Ye, Liang Liang College of Civil Engineering and Architecture East China Jiaotong University Jiangxi Province Nanchang330013 China Changsha University of Science and Technology Hunan Changsha410114 China Institute of Energy Research Jiangxi Academy of Sciences Nanchang330096 China Jiangxi Carbon Neutralization Research Center Nanchang330096 China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan430071 China

The goaf volume in the vacancy method of hard rock mines is significantly larger than the filling capacity, forming layered and inclined planes during the large-scale filling process. This results in unclear mechanical impact mechanisms on the backfill. To investigate the effect of interface inclination angle on the mechanical behavior of backfill, a set of cemented tailings composite backfill (CCTB) samples with interface inclination angles of 15°, 30°, and 45° are prepared. Uniaxial compression tests and digital image correlation techniques are used to investigate the influence of various interface inclination angles on the strength, deformation behavior, and failure mode of the CCTB. The results show that: (1) The uniaxial compressive strength (UCS) of the CCTB weakens with increasing interface inclination angle but consistently shows exponential growth with curing age (CA) regardless of the interface inclination angle. (2) The interface inclination angle controls the behavior and classification characteristics of the stress-strain curve of CCTB samples, and the increase of interface inclination angle weakens the elastic modulus. (3) The interface inclination angle significantly influences the failure mode and classification characteristics of the samples compared to CA and tailing-to-cement ratio (TCR), with shear slip failure induced by the former and axial splitting failure induced by the latter. The research provides a theoretical basis for understanding the mechanical behavior and stability control of inclined CCTB in underground mining. © 2024, The Authors. All rights reserved.

关键词： Image correlation

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Role of molybdenum compounds in enhancing denitrification: Structure-activity relationship and the regulatory mechanisms

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Chemosphere 2024年 367卷 143433页

作者： Zhang, Ying Sun, Hejiao Lu, Caicai Li, Haibo Guo, Jianbo Experimental Education Center Beijing Normal University at Zhuhai Jinfeng Road 18 Zhuhai519000 China Deep Space Exploration Laboratory/School of Earth and Space Sciences University of Science and Technology of China Hefei230026 China School of Environmental and Municipal Engineering Tianjin Key Laboratory of Aquatic Science and Technology Tianjin Chengjian University Jinjing Road 26 Tianjin300384 China School of Civil Engineering and Architecture Taizhou University Zhejiang Taizhou318000 China

The effect and regulatory mechanisms of molybdenum compounds (MoO2, MoS2, MoSe2 and MoSi2) on denitrification were investigated by structure-activity relationships, electrochemical characteristics, microbial metabolism analysis and bacterial community distribution. All the assessed molybdenum compounds exhibited the enhancement effect on denitrification, in the order of MoS2 > MoSi2 > MoSe2 > MoO2, with MoS2 increasing 7.08-fold in 12 h. Analysis of structure-activity relationships suggested that the molybdenum compounds with lower negative redox potential and higher redox reversibility were favorable for promoting denitrification. According to the morphology observation, the interactions between Mo compounds and denitrifying bacteria may be beneficial to extracellular electron transfer. Molybdenum compounds with electron transfer capability facilitated an increase in electron capacitance from 835.1 to 1011.3 μF, promoting the electron exchange rate during denitrification. In the denitrification electron transport chain, the molybdenum compounds upregulated nicotinamide adenine dinucleotide and denitrifying enzyme activity, as well as facilitated the abundance of quinone pools, ATP translocation, and cytochrome c related proteins. Moreover, Mo compounds enriched functional bacteria such as electroactive bacteria and denitrifying functional bacteria. Notably, Mo ions in molybdenum compounds may provide active sites for nitrate reductase, optimizing the electron distribution of the denitrification process and thus improved the partial denitrification efficiency. This work aimed to further understand the regulatory mechanisms of molybdenum on denitrification electron transfer in the compound state and to anticipate the catalytic role of Mo compounds for sustainable water treatment. © 2024 Elsevier Ltd

关键词： Nitrates

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Determining the suitable ecological water level based on the response relationship between landscape connectivity and water level: A case study of Poyang Lake, China

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Ecological Indicators 2025年 175卷

作者： Zhang, Cheng Chen, Wenbo Huang, Fangfang School of Environmental Science and Engineering Zhejiang University of Water Resources and Electric Power Hangzhou310018 China Institute of Ecological Barrier for Coastal Zone Zhejiang University of Water Resources and Electric Power Hangzhou310018 China School of Surveying and Spatial Information Engineering East China University of Technology Nanchang330013 China Jiangxi Key Laboratory of Basin Ecological Process and Information East China University of Technology Nanchang330013 China School of Civil Engineering and Architecture Zhejiang Guangsha Vocational and Technical University of Construction Dongyang322100 China

Water level is an important indicator of hydrological regime of lake, and its spatio-temporal variation has a profound impact on habitat quality and biodiversity conservation. How to determine the suitable ecological water level has long been a hot issue in ecohydrology research. Taking Poyang Lake as a case and from the perspective of habitat, this study firstly used the range of variability approach (RVA) to analyze the natural water level regime of the lake. Then, the probability of connectivity (PC) was applied to analyze the dynamics of grassland connectivity and water connectivity after identifying the distribution pattern of grassland and water body at different water levels. Finally, the natural water level regime was corrected to the suitable ecological water level based on the response relationship between grassland connectivity, water connectivity and water level. The results showed as follows: (1) The annual variation of water level in Poyang Lake showed a significant unimodal distribution, with high water level in flood season from April to September and low water level in dry season from October to March of the following year. The annual water level can reach the highest of 22.63 m in July and the lowest of 7.12 m in February from 2000 to 2020. (2) The grassland and water body constitute the main habitats of Poyang Lake wetland. Under the disturbance of hydrological process, they presented the unique dynamic tradeoff relationships of "One shrinks while the other expands" and "One is fragmented while the other is connected", respectively. With the increase of water level, grassland connectivity decreased dramatically while water connectivity increased progressively. (3) The annual demand for suitable ecological water level is 14.82–15.65 m. In the wet season, the threshold of suitable ecological water is 14.82–16.96 m, while it is 11.75–14.82 m in the dry season. The threshold of monthly suitable ecological water level from January to December is succes

关键词： Biotic

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Resilience Assessment of Subway System to Waterlogging Disaster

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SSRN 2024年

作者： Xu, Fei Fang, Delin Chen, Bin Wang, Hao State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal University Beijing100875 China Faculty of Geographical Science Beijing Normal University Beijing100875 China State Key Joint Laboratory of Environmental Simulation and Pollution Control China Faculty of Architecture Civil and Transportation Engineering Beijing University of Technology Beijing100124 China

The subway system is experiencing significant challenges from waterlogging due to climate change and urbanization, and the enclosed underground structure of the system makes this issue worsen. This study proposed a "Stability-Resistance-Recovery" assessment framework focused on subway system waterlogging resilience (SSWR) based on the system performance curve. This framework considered various factors, including the inundation situation simulated by hydrological model, natural environment, subway information, and sociodemographic information. A case study in Beijing showed that the stability and resistance were the leading factors affecting the SSWR. Among all the indexes, water bodies surface percentage, evening peak departure time interval, and population density had the strongest impacts on the SSWR. Generally, the subway system exhibited a relatively low level of waterlogging resilience, with 51.9% of stations indicating very low or low levels, mainly distributed on subway lines 1, 2, 4, 5, 7, 9, and 10. Stations at medium SSWR were dispersed throughout the areas neighboring stations at very low or low SSWR. Stations at very high or high SSWR were minimal and scattered in peripheral areas. This study identifies the resilience level of subway stations and provides theoretical support for decision-makers to allocate waterlogging prevention and recovery resources for subway system. © 2024, The Authors. All rights reserved.

关键词： Recovery

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Image-based numerical study of three-dimensional meso-structure effects on damage and failure of heterogeneous coal-rock under dynamic impact loads

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Particuology 2020年第4期18卷 132-141页

作者： Kehong Zheng Bingjing Qiu Zhenyu Wang Xuefeng Li Jianping Li Kuidong Gao College of Civil Engineering and Architecture Zhejiang UniversityHangzhou 310058China School of Energy and Mechanical Engineering Nanjing Normal UniversityNanjing 210000China College of Mechanical and Electrical Engineering China University of Mining and Technology Xuzhou 221116China College of Mechanical&Electrical Engineering Shandong University of Science&Technology Qingdao 266000China

This paper proposes a numerical three-dimensional(3D)mesoscopic approach based on the discrete element method combined with X-ray computed tomography(XCT)images to characterize the dynamic impact behavior of heterogeneous coal-rock(HCR).The dynamic impact loading in three directions was modelled to investigate the effects of the 3D meso-structure on the failure patterns and fracture mechanism,with different impact *** XCT image-based discrete element model of HCR was calibrated through appropriate standard uniaxial compression *** simulations were carried out to investigate how the breakage behaviors are affected by different loading directions with different impact *** loading direction,input energy,and spatial distribution of the mineral phase had a remarkable influence on the failure patterns and load-carrying *** shape of the gangue phase and the approximate location of the gangue interfaces are key parameters to consider when investigating the failure patterns and fracture mechanism of heterogeneous rock *** damage and fracture tended to propagate from the surfaces to the HCR *** gangue phase area contacting the loading wall,growth direction of the strong gangue interfaces,and loading directions greatly influenced the failure patterns of the heterogeneous rock materials.

关键词： Heterogeneous coal-rock Impact loads X-ray computed tomography(XCT) 3D image-based discrete element modelling Failure pattern

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Mechanical Characteristics and Microstructural Changes in Phosphogypsum-Cement-Lime Composite Modified Loess

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SSRN 2024年

作者： Chang, Jin Li, Jue Wang, Yudan Zhang, Haina Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure Department of Civil Engineering Shanghai Jiao Tong University Shanghai200240 China College of Civil Engineering Changsha University Changsha410022 China Hunan Engineering Research Center for Intelligent Construction of Fabricated Retaining Structures Changsha University Changsha410022 China Changsha University of Science & Technology Hunan Changsha410114 China National & Local Joint Engineering Research Center of Transportation and Civil Engineering Materials Chongqing Jiaotong University Chongqing400074 China College of Civil Engineering and Architecture East China Jiaotong University Jiangxi Province Nanchang330013 China

Loess is widely distributed in China but suffers from inherent deficiencies limiting its direct use as a base material in road construction without modifications. This study investigated the utilization of Phosphogypsum (PG), an industrial waste, in a composite stabilizer containing cement, lime and slag powder for modifying loess in the subbase application. An orthogonal test design was employed to optimize the composite proportions. Laboratory tests evaluated the mechanical properties including unconfined compressive strength (UCS), splitting tensile strength, resilient modulus and water stability of modified loess over curing periods up to 90 days. Microstructural evolution was analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed the composite containing 25% PG, a cement-slag ratio of 4:6 and 5% lime imparted the highest strengths. Mechanical performances increased with curing time and stabilizer content. Water stability and heavy metal immobilization were satisfactory. Microstructural results revealed microstructural densification occurred through hydration product development binding soil particles. This work demonstrated the technical and environmental viability of recycling PG through loess improvement, offering a sustainable solution for problematic soil stabilization and industrial waste utilization. © 2024, The Authors. All rights reserved.

关键词： Lime

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Resilience Assessment of Subway System to Waterlogging Disaster

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SSRN 2023年

作者： Xu, Fei Fang, Delin Chen, Bin Wang, Hao State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal University Beijing100875 China Faculty of Geographical Science Beijing Normal University Beijing100875 China School of Environment Beijing Normal University Beijing100875 China Faculty of Architecture Civil and Transportation Engineering Beijing University of Technology Beijing100124 China

The subway system is experiencing significant challenges from waterlogging due to climate change and urbanization, and the enclosed underground structure of the system makes the issue worsen. This study proposed the "Stability-Resistance-Recovery" assessment framework focused on subway system waterlogging resilience (SSWR), based on the system performance curve. This framework considered various factors, including inundation situation simulated by hydrological model, natural environment, subway information, and socio-demographic information. The case study in Beijing showed that the stability and resistance were the leading factors affecting the SSWR. Among all the indexes, water bodies surface percentage, evening peak departure time interval, and population density had the strongest impact on the SSWR. Generally, the subway system exhibited a relatively low level of SSWR, with 51.9% of stations indicating very low or low levels, mainly distributed on subway lines 1, 2, 4, 5, 7, 9, and 10. Stations at medium SSWR were dispersed throughout areas neighboring stations at very low and low SSWR. Stations at very high or high SSWR were minimal and scattered in peripheral areas. This research identifies the resilience level of subway station, and provides theoretical support for decision-makers to allocate waterlogging prevention and recovery resources. © 2023, The Authors. All rights reserved.

关键词： Recovery

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Influence of the source and molecular weights on sulfathiazole/sulfadiazine binding in sedimentary dissolved organic matter

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Journal of Environmental Management 2025年 386卷 125795页

作者： Yan, Caixia Zhang, Fei Nie, Minghua Luo, Yanqing Ding, Mingjun Nie, Shuhua Zhou, John L. College of Geography and Environmental Science Key Laboratory of Earth Surface Processes and Environmental Change of Tropical Islands Hainan Normal University Haikou571158 China School of Geography and Environment Key Laboratory of Poyang Lake Wetland and Watershed Research Ministry of Education Jiangxi Province Key Laboratory of Ecological Intelligent Monitoring and Comprehensive Treatment of Watershed Jiangxi Normal University 99 Ziyang Road Nanchang330022 China Jiangxi Drug Inspection Center 1566 Beijing East Road Nanchang330029 China School of Civil and Environmental Engineering University of Technology Sydney SydneyNSW 2007 Australia

Sedimental dissolved organic matter (DOM) plays a crucial role in the migration of antibiotics in a lake environment, which is strongly associated with its physicochemical properties influenced by temporal and spatial variations. This study systematically investigated the binding behavior of sulfathiazole (ST) and sulfadiazine (SD) to DOM across different molecular weights (MWs) in sediments from Poyang Lake using multiple spectroscopic techniques. Results showed that the MW fractions of DOM from the onset of the dry season were higher than those before flooding. Additionally, key carbon parameters, including dissolved organic carbon and fluorescent components, were present in greater proportion in the truly dissolved phase and the low MW fraction of DOM. These properties of the low MW fraction of DOM enhanced its binding capacity for the two sulfonamides, with the partitioning coefficient (logKcoc) values of 5.20 and 5.06 for ST and SD, respectively. Dialysis experiments investigating the interaction between different concentrations of DOM and sulfonamides indicated that humic-like and protein-like components significantly influenced the migration of ST and SD, respectively. Moreover, protein-like components exerted a more substantial impact on the migration of sulfonamides in heavily polluted sampling sites, while the humic-like substances played a more significant role for the samples from the wetland protection area. The results enhanced the understanding of the significance of DOM sources and MW in influencing the environmental fate of antibiotics in lake ecosystems. © 2025

关键词： Lake pollution

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Role of Molybdenum Compounds in Enhancing Denitrification: Structure-Activity Relationship and the Regulatory Mechanisms

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SSRN 2024年

作者： Zhang, Ying Sun, Hejiao Lu, Caicai Li, Haibo Guo, Jianbo Experimental Education Center Beijing Normal University at Zhuhai Jinfeng Road 18 Zhuhai519000 China CAS Key Laboratory of Crust-Mantle Materials and Environments University of Science and Technology of China Hefei230026 China School of Environmental and Municipal Engineering Tianjin Key Laboratory of Aquatic Science and Technology Tianjin Chengjian University Jinjing Road 26 Tianjin300384 China School of Civil Engineering and Architecture Taizhou University Zhejiang Taizhou318000 China

The effect and regulatory mechanisms of molybdenum compounds (MoO2, MoS2, MoSe2 and MoSi2) on denitrification were investigated by structure-activity relationships, electrochemical characteristics, microbial metabolism analysis and bacterial community distribution. MoO2, MoS2, MoSe2 and MoSi2 all exhibited positive effect on denitrification, with MoS2 increasing the nitrate reduction rate by 7.08-fold. Analysis of structure-activity relationships suggested that the molybdenum compounds with lower negative redox potential and higher redox reversibility were favorable for promoting denitrification. According to the morphology observation, the interactions between molybdenum compounds and denitrifying bacteria may be beneficial to extracellular electron transfer. The molybdenum compounds with electron transfer capability facilitated an increase in electron capacitance of the denitrification system, reduction of the system impedance, and promotion of electron transfer rate. In the denitrification electron transport chain, the molybdenum compounds upregulated nicotinamide adenine dinucleotide and denitrifying enzyme activity, as well as facilitated the abundance of quinone pools, ATP translocation, and cytochrome c related proteins. Moreover, molybdenum compounds enriched functional bacteria such as electroactive bacteria and denitrifying functional bacteria. Therefore, it is proposed that compound-state molybdenum may provide active sites for nitrate reductase and optimize the electron distribution of denitrification enzymes, thereby improving denitrification efficiency. This work aimed to further understand the regulatory mechanisms of molybdenum on denitrification electron transfer in the compound state and to anticipate the catalytic role of molybdenum compounds for sustainable water treatment. © 2024, The Authors. All rights reserved.

关键词： Denitrification

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Methods for Performance Optimization of Ultra-Thin Heat Pipes with Composited Wick

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SSRN 2024年

作者： Yin, Kui Wu, Yongjia Zhao, Donghao Lin, Wenting Zhou, Nan Li, Zhiyong Ming, Tingzhen School of Civil Engineering and Architecture Wuhan University of Technology Wuhan430070 China Sanya Science and Education Innovation Park Wuhan University of Technology Sanya572004 China School of Computer and Information Science Chongqing Normal University Chongqing401331 China Energy Technologies Area Lawrence Berkeley National Laboratory 1 Cyclotron Road BerkeleyCA94720 United States UC Berkeley United States

Ultra-thin heat pipes are extensively utilized in the heat dissipation systems of portable electronic devices, with the performance of their core component, the wick, being crucial to their normal operation. The composite structure of a copper mesh and copper fiber bundle wick can significantly enhance the maximum heat transfer capacity of ultra-thin heat pipes. A mathematical model of the ultra-thin heat pipe, incorporating the new composite wick structure, was developed using the Hagen-Poiseuille equation. Based on this mathematical model, the new wick structure was optimized to enhance the maximum heat transfer capacity. Additionally, the mechanisms by which the number of copper mesh layers, the width, and the positions of copper fiber bundles influence thermal performance were elucidated. The optimization results indicated that the heat pipe achieved optimal heat transfer performance with a single layer of copper mesh, a 0.75 mm width copper fiber bundle, and zero position. The optimized wick structure enhanced the maximum heat transfer capacity of the heat pipe by 40.03% compared to its capacity before optimization. © 2024, The Authors. All rights reserved.

关键词： Heat pipes

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