作者机构:
[Li, Yi] Hubei Univ Technol, Sch Civil Engn Architecture & Environm, Wuhan 430068, Peoples R China.;[Liu, Yaning] Univ Colorado Denver, Dept Math & Stat Sci, Denver, CO 80204 USA.;[Li, Yi] Changsha Univ Sci & Technol, Sch Hydraul Engn, Changsha 410114, Peoples R China.;[Hu, Bin] Chinese Acad Sci, Key Lab Drinking Water Sci & Technol, Res Ctr Ecoenvironm Sci, Beijing 100085, Peoples R China.;[Hu, Bin] Univ Chinese Acad Sci, Beijing 100049, Peoples R China.
通讯机构:
[Li, Y ] C;Changsha Univ Sci & Technol, Sch Hydraul Engn, Changsha 410114, Peoples R China.
关键词:
Compressed air energy storage in aquifers;Shallow aquifer;Highly permeable leakage path;Wellbore-reservoir model;Brine and air leakage
摘要:
The potential leakage influences of compressed air energy storage in aquifers, especially on the overlying shallow aquifer environment, need more attention, but there is still a lack of relevant studies. In this research, a coupled wellbore-reservoir underground anticline model is simulated using T2Well/EOS3. Two-phase non-Darcy flows, different from the multiphase Darcy flow in porous media, are considered in both the central working wellbore and a highly permeable leakage path. In an anticline, the results show that the leakage rate will decline and reach a relatively steady state as the cycles continue. The final continuous small periodic oscillations of leakage rate occur with a hysteresis effect with respect to cycle injection-production. When air leakage occurs in the initial gas bubble process, it gradually disappears and gets replaced by brine leakage. A decrease in the reservoir permeability can result in a larger initial leakage rate, but a smaller rate and fluctuation during the cycle process. However, in a horizontal reservoir, strong gas fingering increases the risk of air leakage, which, once occurs, can last during the rest of the process. This research can deepen the understanding of the leakage process and help evaluate and prevent incidents of environmental contamination in gas storage in aquifers.
摘要:
Due to rapid development, the occurrence of flood has become more and more frequent. However, due to the complex nature and limited knowledge, the conventional hydrological model for flood forecasting purposes faces drawbacks in terms of technical difficulties. Hence, it is essential to have a model which can provide a considerably high level of accuracy for flood forecasting. This study selected the area between the Xiangtan station and Changsha station, located in Xiangjiang River as the study area. Recurrent neural network (RNN), gated recurrent unit (GRU) and long short-term memory (LSTM) were applied for model development purposes. The models were used to forecast the flood disasters occurring in 2017, 2019, 2020 and 2022 for 1h, 6h and 12h in advance. A series of statistical analyses have been conducted to evaluate the model performance. The LSTM model outperformed than the RNN and GRU models. In terms of the overall analysis, the LSTM model achieved relatively good accuracy with a NSE of above 0.98, and RMSE of lower than 0.2 m. In addition, the model with a 6h in advance is the most suitable model to predict the peak flood arrival time with an absolute error of less than 3 hours.
作者机构:
[Yao, Zhen; Bian, Cheng; Jiang, Changbo; Wu, Zhiyuan; Chen, Jie; Liu, Jiaxiang] Changsha Univ Sci & Technol, Sch Hydraul & Environm Engn, Changsha 410114, Peoples R China.;[Jiang, Changbo; Wu, Zhiyuan; Chen, Jie] Key Lab Dongting Lake Aquat Ecoenvironm Control &, Changsha 410114, Peoples R China.;[Jiang, Changbo; Wu, Zhiyuan; Chen, Jie] Key Lab Water Sediment Sci & Water Disaster Preven, Changsha 410114, Peoples R China.
关键词:
Coral sediment;Oscillatory flow;Threshold of motion;Shields parameters;Critical near-bottom peak velocity
摘要:
In this study, the incipient motion thresholds of coral sediment with the action of oscillatory currents were experimentally recorded by conducting a total of 405 laboratory experiments, including an analysis of nine sieve median diameters, five water depths, and four wave periods. The coral sediment Shields parameters for oscillatory flow were compared to those for unidirectional flow and to those of shell Shields parameters for oscillatory flow. The results showed that there was an extensive scatter range in the Shields parameter for oscillatory flow of coral sediments. Additionally, the coral sediment Shields parameter for oscillatory flow was slightly different from that for unidirectional flow. The use of the Shields curve form to represent the coral sediment threshold for oscillatory flow was not appropriate. Using the critical near-bottom peak velocity to represent the incipient motion threshold of coral sediment for oscillatory flow was a better option. The use of experimental particle data analyses and the equation for the critical near-bottom peak velocity of quartz sand for oscillatory flow was modified to obtain a critical near-bottom peak velocity equation for coral sediment. This equation adds the influence of shape through the median Corey shape factor.
摘要:
The reef-lagoon-channel system is very typical on the low-lying reef-lined coasts in tropical and subtropical areas. Comparing to the well-studied one-dimensional horizontal (1DH) fringing reefs, little is known about the alongshore wave runup variation and its implication for coastal flooding in such a two-dimensional horizontal (2DH) reef configuration. To better understand the wave processes in an idealized reef-lagoon-channel system, a numerical model is presented in this study, which is based on a set of fully nonlinear Boussinesq equations. Wave breaking is addressed by a shock-capturing scheme and bottom friction is formulated by the Manning frictional law. The adopted model is first validated by a published laboratory dataset in view of wave spectrum, wave height, wave setup, mean current as well as wave runup on the back-reef beach. Subsequently, the effects of hydrodynamic (incident wave height, incident wave period, reef-flat wave level) and reef morphological (fore-reef slope, cross-shore reef-flat width, channel width and frictional coefficient) parameters that are not fully considered by the laboratory experiments are investigated through the numerical simulations. Finally, the model is used to analyze the infragravity (IG) wave resonant modes in the system, and the effects of channel on such modes are also demonstrated.
作者:
Yao, Yu;Zhou, Baobao;Zhao, Zhongwei;Chen, Xianjin;Chen, Long
期刊:
海洋学报(英文版),2023年42(7):41-50 ISSN:0253-505X
通讯作者:
Zhao, ZW
作者机构:
[Yao, Yu; Chen, Long; Zhou, Baobao; Chen, Xianjin] Changsha Univ Sci & Technol, Sch Hydraul & Environm Engn, Changsha 410114, Peoples R China.;[Zhao, Zhongwei; Zhao, ZW] Chinese Acad Sci, South China Sea Inst Oceanol, Key Lab Ocean & Marginal Sea Geol, Guangzhou 511458, Peoples R China.;[Yao, Yu; Chen, Long] Key Lab Water Sediment Sci & Water Disaster Preven, Changsha 410114, Peoples R China.
通讯机构:
[Zhao, ZW ] C;Chinese Acad Sci, South China Sea Inst Oceanol, Key Lab Ocean & Marginal Sea Geol, Guangzhou 511458, Peoples R China.
关键词:
coastal morphodynamics;sea level rise;reef island;wave-flume experiment;XBeach model
摘要:
The persistence and habitability of coral reef islands in future extreme oceanographic conditions has received increasing attention in the recent decade, concerning that the sea level rise (SLR) and more frequent and intense storms in the context of global climate change are expected to destabilize those islands. Here, we conduct a set of wave-flume laboratory experiments focusing on the morphodynamic change of reef islands to varying ocean forcing conditions (wave height and SLR). Subsequently, a phase-resolving XBeach numerical model is adopted to simulate the monochromatic wave process and its associated sediment dynamics. The adopted model is also firstly validated by laboratory experimental results as reported in this study. It is then used to examine the impacts of island morphological factors (island width, island height, island location and island side slope) on the island migration. The combined laboratory/physical and numerical experiment outputs suggest that reef islands can accrete vertically in response to the sea level rise and the increased storminess.
摘要:
Bimetallic sulfides have distinctive catalytic property in activating peroxymonosulfate (PMS) for water remediation. Polyoxometalates as potential precursors have rarely been reported for the catalytic degradation of refractory organic pollutants. Herein, a composite catalyst of Co-Mo bimetallic sulfides supported onto graphene oxide (O-CoMoS/GO) with a heterojunction architecture was synthesized through a hydrothermal strategy with polyoxometalates ((NH(4))(4)[Co(II)Mo(6)O(24)H(6)]·6H(2)O) as the precursor and applied in the PMS activation. This material showed a superior performance for the catalytic degradation of the model organic pollutant, 4-chlorophenol (rapidly removed within 10min with an apparent reaction rate constant of 0.5458min(-1)). O-CoMoS/GO outperformed most of the reported catalysts in terms of activity and had a strong tolerance towards common organic and inorganic compounds in water, and could perform well in different real water systems. Experimental and theoretical results indicated that the introduction of GO could achieve the enrichment of electrons on the metals and reduce the d band center (ε(d)) of Co close to the Fermi level (ε(F)), thereby facilitating the interfacial electron transfer process. The activation mechanism was due to the as-prepared bimetallic sulfides and the formation of heterojunction structure with GO, where Co(II) as the active center could be regenerated by the adjacent Mo element (as co-catalyst) and by gathering electrons from GO through the Co/Mo-O-C coupling. This work provides insights into the design of bimetallic sulfide catalysts in activating PMS for water remediation.
期刊:
Journal of Marine Science and Engineering,2023年11(1) ISSN:2077-1312
通讯作者:
Ke Qu
作者机构:
[Wang, Xu; Lie, Yancheng; Li, Xiaohan; Qu, Ke] Changsha Univ Sci & Technol, Sch Hydraul & Environm Engn, Changsha 410114, Peoples R China.;[Qu, Ke] Key Lab Water Sediment Sci & Water Disaster Preven, Changsha 410114, Peoples R China.;[Qu, Ke] Key Lab Dongting Lake Aquat Eco Environm Control &, Changsha 410114, Peoples R China.
通讯机构:
[Ke Qu] S;School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha 410114, China<&wdkj&>Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, Changsha 410114, China<&wdkj&>Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha 410114, China
关键词:
focused wave;extreme wave;wave attenuation;rigid vegetation patch;nonhydrostatic model
摘要:
During severe weather, the runup of the devasting surges and waves can cause extensive damages to the coastal facilities and results in significant loss of life. Therefore, it becomes necessary to find reliable measures to reduce the wave runup in coastal regions. As a natural barrier to the shorelines, coastal vegetation has great potential to attenuate wave runup and to prevent the coastal communities from extreme floodings and huge land loss. This study numerically discusses the influences of the emergent vegetation patch on the runup processes of extreme wave groups by applying a nonhydrostatic flow solver. Influences of the major factors, i.e., water depth, peak wave period, significant wave height, and density and length of the vegetation patch, are analyzed in detail. Research findings indicate that the presence of the emergent vegetation patch can substantially dissipate most of the incident wave energy and effectively reduce the maximum wave runup heights of extreme wave groups at the sloped beach. It is hoped that the research results of this study will be helpful to the design of coastal soft protection measures.
通讯机构:
[Xiaomin Gong] C;College of Resources and Environment, Hunan Agricultural University, Changsha, China<&wdkj&>Key Laboratory for Rural Ecosystem Health in the Dongting Lake Area of Hunan Province, Changsha, China
摘要:
Main conclusion This review proposed that phytoremediation could be applied for the decontamination of MPs/NPs.Micro- and nano-plastics (MPs < 5 mm; NPs < 100 nm) are emerging contaminants. Much of the recent concerns have focused on the investigation of their pollution and their potential eco-toxicity. Yet little review was available on the decontamination of MPs/NPs. Recently, the uptake of MPs/NPs by plants has been confirmed. Here, in view of the current knowledge, this review introduces MPs/NPs pollution and highlights the updated information about the interaction between MPs/NPs and plants. This review proposed that phytoremediation could be a potential possible way for the in situ remediation of MPs/NPs-contaminated environment. The possible mechanisms, influencing factors, and existing problems are summarized, and further research needs are proposed. This review herein provides new insights into the development of plant-based process for emerging pollutants decontamination, as well as the alleviation of MPs/NPs-induced toxicity to the ecosystem.
摘要:
Replacing natural aggregates in concrete with waste rubber particles is an effective method to solve environmental problems, but the use of rubber due to its unknown characteristics can change the fracture performance and cracking behavior of self-compacting concrete. Hence, through experimental analysis and discrete element method (DEM) simulation, this paper aims to investigate the influence of different rubber contents (0%, 10%, 20% and 30%) on fracture characteristics of self-compacting concrete. Compared with natural river sand, rubber particles have more flexible structure and stronger deformation ability, and these unique properties enhance the bridging effect between matrices and weaken the stress concentration at the crack tip, which shows that the fracture parameters of self-compacting rubberized concrete (SCRC) increase linearly with the increase of rubber content, and this linear growth rate will increase with the increase of beam size. Moreover, the addition of rubber particles absorbs most of the energy generated in the fracture process, which significantly enhances the anti-cracking ability of SCRC, and this ability to prevent crack propagation will be enhanced with the increase of rubber content, which is manifested by the significant decrease of acoustic emission (AE) activity. Based on the shapes of real aggregates and rubber particles, a universal DEM fracture prediction model for SCRC is established, which can better describe the fracture response of SCRC with different rubber contents and sizes under flexural loads. The evaluation of economic and environmental benefits indicates that adding rubber particles into self-compacting concrete can not only save costs, but also produce considerable environmental benefits.
期刊:
Proceedings of the Institution of Civil Engineers: Civil Engineering,2023年 ISSN:0965-089X
通讯作者:
Yu, JH
作者机构:
[Yu, Xiangmin] Shanghai Univ, Sch Mech & Engn Sci, Shanghai, Peoples R China.;[Chen, Dewei] Tongji Univ, Coll Civil Engn, Shanghai, Peoples R China.;[Yu, Jinhong] Changsha Univ Sci & Technol, Sch Hydraul & Environm Engn, Key Lab Water Sediment Sci & Water Disaster Preven, Changsha, Peoples R China.
通讯机构:
[Yu, JH ] C;Changsha Univ Sci & Technol, Sch Hydraul & Environm Engn, Key Lab Water Sediment Sci & Water Disaster Preven, Changsha, Peoples R China.
关键词:
bridges;construction;steel structures;structural design;UN SDG 9: Industry, innovation and infrastructure
摘要:
Many steel truss cable-stayed bridges have been built in China in the past two decades, providing a wealth of design and construction experience. This paper provides a review of their development, the structural configurations used, the mechanical characteristics of decks, pylons and cables, and the various innovative construction methods adopted. With main spans now exceeding 1 km, the sturdy structures are mainly used for combined rail-and-road crossings in preference to more flexible suspension bridges. The aim of the paper is to provide a comprehensive and useful reference for further design and construction of steel truss cable-stayed bridges worldwide.
摘要:
Different doses (1%, 5%, 10%, mass fraction) of animal manure compost were added into a multi-heavy metal contaminated paddy soil for 150 d, and the changes in microbial structure and composition were evaluated. Compost exhibited dose-dependent effects on the rhizosphere bacterial community. Low (1%) and middle (5%) additions of compost exerted more distinct influence on bacterial community structure in rhizosphere soil than in bulk soil. The bacterial diversity after addition of compost decreased in rhizosphere soils compared with that in bulk soil. Results of redundancy analysis (RDA) indicated that different responses of rhizosphere and non-rhizosphere bacterial community to the changed soil physicochemical properties (soil pH, Pb, Cd and Cu levels) might be one reason for the differences. Thus, in agricultural management practice, the influence of compost on rhizosphere microbes should be considered.
作者机构:
[Tao, He; Xie, Yanwu; Jiang, Changbo; Deng, Bin] Changsha Univ Sci & Technol, Sch Hydraul Engn, Changsha 410114, Peoples R China.;[Tang, Hansong] CUNY City Coll, Civil Engn Dept, Unitetd Sates, New York, NY 10031 USA.;[Jiang, Changbo; Deng, Bin] Key Lab Water Sediment Sci & Water Disaster Preven, Changsha 410114, Peoples R China.
通讯机构:
[Hansong Tang] C;Civil Engineering Department, City College of New York, New York, 10031, NY, Unitetd Sates
关键词:
Solitary wave;Sandy beach;Breakwater;Spill hole;Deposition and erosion;Scour
摘要:
This paper presents a numerical study on erosion and deposition of a sandy beach installed with a breakwater bearing spill holes, aiming to understand its performance in erosion reduction. The two-dimensional (2D) governing equations for the water-sand mixture are solved by the VOF method and other techniques. The numerical approaches are validated against experimental data for wave propagation on an impermeable beach with a breakwater, scour underneath a pipeline, scour in front of a breakwater, and erosion and deposition of a sandy beach. On these bases, numerical simulations are made for three scenarios: a sandy beach, a sandy beach with a breakwater, and a sandy beach with a breakwater with spill holes. Then, the study proceeds to a detailed investigation of the third scenario with different breakwater locations, spill hole sizes, water depths, and wave heights. The results indicate that the breakwater indeed reduces beach erosion, and the breakwater location and wave height have a pronounced influence on the erosion. The breakwater's performance in reducing beach erosion achieves a maximum at a specific size of the hole opening. It is anticipated that the understanding revealed in this study sheds light on the design and application of breakwaters.