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Comparative evaluation of SPE methods for biotoxicity assessment of water and wastewater:Linkage between chemical extracting efficiency and biotoxicity outcome

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Journal of Environmental Sciences 2024年第8期142卷 33-42页

作者： Jiawei Zhou Shihao Wang Xiwei He Hongqiang Ren Xu-Xiang Zhang State key laboratory of Pollution control and Resource Reuse School of EnvironmentNanjing UniversityNanjing 210023China

Biotoxicity assessment results of environmental waters largely depend on the sample extraction protocols that enrich pollutants to meet the effect-trigger thresholds of ***,more chemical mixture does not necessarily translate to higher combined ***,there is a need to establish the link between chemical extracting efficiency and biotoxicity outcome to standardize extraction methods for biotoxicity assessment of environmental *** study compares the performance of five different extraction phases in solid phase extraction(SPE),namely HLB,HLB+Coconut,C18 cartridge,C18 disk and strata-X,and evaluated their chemical extracting efficiencies and biotoxicity *** quantitatively assessed cytotoxicity,acute toxicity,genotoxicity,estrogenic activity,and neurotoxicity of the extracts using in vitro bioassays and characterized the chemical extracting efficiencies of the SPE methods through chemical recoveries of 23 model compounds with different polarities and total organic *** Pareto ranking,we identified HLB+Coconut as the optimal SPE method,which exhibited the highest level of water sample biotoxicity and recovered the most chemicals in water *** found that the biotoxicity outcomes of the extracted water samples significantly and positively correlated with the chemical extracting efficiencies of the SPE ***,we observed synchronous changing patterns in biotoxicity outcome and chemical extracting efficiencies in response to increasing sample volumes per cartridge(SVPC)during *** findings underscore that higher chemical extracting efficiency of SPE corresponds to higher biotoxicity outcome of environmental water samples,providing a scientific basis for standardization of SPE methods for adequate assessment of biotoxicities of environmental waters.

关键词： Biotoxicity Chemical recovery Solid phase extraction Surface water Wastewater

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Roughness characterization and shearing dislocation failure for rock-backfill interface

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International Journal of minerals,Metallurgy and Materials 2024年第6期31卷 1167-1176页

作者： Meifeng Cai Zhilou Feng Qifeng Guo Xiong Yin Minghui Ma Xun Xi key laboratory of High-Efficient mine and Safety of Metal mines of Ministry of Education Beijing 100083China key laboratory of Urban and Underground Space Engineering University of Science and Technology BeijingBeijing 100083China Shandong Gold Group Co LtdJinan 250102China

Shearing dislocation is a common failure type for rock–backfill interfaces because of backfill sedimentation and rock strata movement in backfill mining *** paper designed a test method for rock–backfill shearing *** digital image techno-logy and three-dimensional(3D)laser morphology scanning techniques,a set of 3D models with rough joint surfaces was ***,the mechanical behavior of rock–backfill shearing dislocation was investigated using a direct shear *** effects of interface roughness on the shear–displacement curve and failure characteristics of rock–backfill specimens were *** 3D fractal dimen-sion,profile line joint roughness coefficient(JRC),profile line two-dimensional fractal dimension,and the surface curvature of the frac-tures were *** correlation characterization of surface roughness was then analyzed,and the shear strength could be measured and calculated using *** results showed the following:there were three failure threshold value points in rock–backfill shearing dis-location:30%–50%displacement before the peak,70%–90%displacement before the peak,and 100%displacement before the peak to post-peak,which could be a sign for rock–backfill shearing dislocation *** surface JRC could be used to judge the rock–backfill shearing dislocation failure,including post-peak sliding,uniform variations,and gradient change,corresponding to rock–backfill disloca-tion failure on the field *** research reveals the damage mechanism for rock–backfill complexes based on the free joint surface,fills the gap of existing shearing theoretical systems for isomerism complexes,and provides a theoretical basis for the prevention and control of possible disasters in backfill mining.

关键词： rock–backfill roughness correlation characterization shearing dislocation interface failure

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Stability mechanism and control of the pumpable supports in longwall recovery room

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International Journal of Mining Science and Technology 2024年第7期34卷 957-974页

作者： Dong Zhang Jianbiao Bai Zhijun Tian Zizheng Zhang Yonghong Guo Rui Wang Ying Xu Hao Fu Shuai Yan Min Deng Shuaigang Liu State key laboratory of Coal Resources and Safe Mining China University of Mining and TechnologyXuzhou 221116China key laboratory of Xinjiang Coal Resources Green Mining Xinjiang Key Laboratory of Coal-bearing Resources Exploration and ExploitationXinjiang Engineering Research Center of Green Intelligent Coal MiningXinjiang Institute of EngineeringUrumqi 830023China Work Safety key laboratory on prevention and control of Gas and Roof disasters for Southern Goal mines Hunan Provincial Key Laboratory of Safe Mining Techniques of Coal MinesHunan University of Science and TechnologyXiangtan 411201China School of mines China University of Mining and TechnologyXuzhou 221116China

The load-bearing performance(LBP)of pumpable supports(PPS)is crucial for the stability of longwall pre-driven recovery room(PRR)surrounding ***,the unbalanced bearing coefficient(UBC)of the PPS(undertaking unequal load along the mining direction)has not been investigated.A mechanical model of the PRR was established,considering the main roof cantilever beam structure,to derive an assessment formula for the load,the failure criteria,and the UBC of the ***,the generation mechanisms,and influencing factors of the UBC were *** sensitivity analysis shows that the main roof hanging length(l_(2))and the spacing between the PPS(r)significantly impact the UBC.A novel design of the PPS and the coupling control technology were proposed and applied to reduce the UBC of the PPS in the adjacent longwall *** results showed no failure of the PPS at the test site,with the UBC(ζ)reduced to 1.1 consistent with the design value(1.15)basically,fully utilizing the collaborative LBP of the ***,the maximum roof-to-floor convergence of the PRR was 234 mm,effectively controlling the stability of the surrounding rock of the PRR and ensuring the mining equipment recovery.

关键词： Pre-driven recovery room Pumpable supports Unbalanced bearing coefficient Hydraulic fracture Stability analysis Surrounding rock control

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HWD-YOLO:A New Vision-Based Helmet Wearing Detection Method

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Computers, Materials & Continua 2024年第9期80卷 4543-4560页

作者： Licheng Sun Heping Li Liang Wang College of Information Science and Technology Beijing University of TechnologyBeijing100124China Chinese Institute of Coal Science Beijing100013China State key laboratory for Intelligent Coal Mining and strata control Beijing100013China Engineering Research Center of Digital Community of Ministry of Education Beijing100124China

It is crucial to ensure workers wear safety helmets when working at a workplace with a high risk of safety accidents,such as construction sites and mine *** existing methods can achieve helmet detection in images,their accuracy and speed still need improvements since complex,cluttered,and large-scale scenes of real workplaces cause server occlusion,illumination change,scale variation,and perspective ***,a new safety helmet-wearing detection method based on deep learning is ***,a new multi-scale contextual aggregation module is proposed to aggregate multi-scale feature information globally and highlight the details of concerned objects in the backbone part of the deep neural ***,a new detection block combining the dilate convolution and attention mechanism is proposed and introduced into the prediction *** block can effectively extract deep featureswhile retaining information on fine-grained details,such as edges and small ***,some newly emerged modules are incorporated into the proposed network to improve safety helmetwearing detection performance *** experiments on open dataset validate the proposed *** reaches better performance on helmet-wearing detection and even outperforms the state-of-the-art *** be more specific,the mAP increases by 3.4%,and the speed increases from17 to 33 fps in comparison with the baseline,You Only Look Once(YOLO)version 5X,and themean average precision increases by 1.0%and the speed increases by 7 fps in comparison with the YOLO version *** generalization ability and portability experiment results show that the proposed improvements could serve as a springboard for deep neural network design to improve object detection performance in complex scenarios.

关键词： Object detection deep learning safety helmet wearing detection feature extraction attention mechanism

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Influence of confined water on the limit support pressure of tunnel face in weakly water-rich strata

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Journal of Central South University 2024年第8期31卷 2844-2859页

作者： Li, Yun-fa Wu, Guo-jun Chen, Wei-zhong Yuan, Jing-qiang Huo, Meng-zhe State key laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan China University of Chinese Academy of Sciences Beijing China

In the process of shield tunneling through soft soil layers, the presence of confined water ahead poses a significant threat to the stability of the tunnel face. Therefore, it is crucial to consider the impact of confined water on the limit support pressure of the tunnel face. This study employed the finite element method (FEM) to analyze the limit support pressure of shield tunnel face instability within a pressurized water-containing layer. Subsequently, a multiple linear regression approach was applied to derive a concise solution formula for the limit support pressure, incorporating various influencing factors. The analysis yields the following conclusions: 1) The influence of confined water on the instability mode of the tunnel face in soft soil layers makes the displacement response of the strata not significant when the face is unstable; 2) The limit support pressure increases approximately linearly with the pressure head, shield tunnel diameter, and tunnel burial depth. And inversely proportional to the thickness of the impermeable layer, soil cohesion and internal friction angle; 3) Through an engineering case study analysis, the results align well with those obtained from traditional theoretical methods, thereby validating the rationality of the equations proposed in this paper. Furthermore, the proposed equations overcome the limitation of traditional theoretical approaches considering the influence of changes in impermeable layer thickness. It can accurately depict the dynamic variation in the required limit support pressure to maintain the stability of the tunnel face during shield tunneling, thus better reflecting engineering reality.

关键词： weakly water-rich strata confined aquifer limit support pressure finite element method multiple linear regression

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Characterizing permeability-porosity relationships of porous rocks using a stress sensitivity model in consideration of elastic-structural deformation and tortuosity sensitivity

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Journal of rock Mechanics and Geotechnical Engineering 2024年第9期16卷 3437-3451页

作者： Ronghe Xu Liqin Wang Xiaoli Zhao Yuze Mao MIIT key laboratory of Aerospace Bearing Technology and Equipment Harbin Institute of TechnologyHarbin150001China State key laboratory of Robotics and System Harbin Institute of TechnologyHarbin150001China Shanghai Aerospace control Technology Institute Shanghai201100China

Clarifying the relationship between stress sensitivities of permeability and porosity is of great significance in guiding underground resource *** and more studies focus on how to construct stress sensitivity models to describe the relationship and obtain a comprehensive stress sensitivity of porous ***,the limitations of elastic deformation calculation and incompleteness of considered tortuosity sensitivity lead to the fact that the existing stress sensitivity models are still unsatisfactory in terms of accuracy and ***,a more accurate and generic stress sensitivity model considering elastic-structural deformation of capillary cross-section and tortuosity sensitivity is proposed in this *** elastic deformation is derived from the fractal scaling model and Hooke's *** the effects of elastic-structural deformation on tortuosity sensitivity,an empirical formula is proposed,and the conditions for its applicability are *** predictive performance of the proposed model for the permeability-porosity relationships is validated in several sets of publicly available experimental *** experimental data are from different rocks under different pressure *** mean and standard deviation of relative errors of predicted stress sensitivity with respect to experimental data are 2.63%and 1.91%.Compared with other models,the proposed model has higher accuracy and better predictive generalization *** is also found that the porosity sensitivity exponent a,which can describe permeability-porosity relationships,is 2 when only elastic deformation is considered.a decreases from 2 when structural deformation is also *** addition,a may be greater than 3 due to the increase in tortuosity sensitivity when tortuosity sensitivity is considered even if the rock is not fractured.

关键词： Stress sensitivity model Permeability-porosity relationships Elastic-structural deformation Tortuosity stress sensitivity

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梯度应力条件下隧道轴向应力对围岩力学响应及破裂特性的影响

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Journal of Central South University 2024年第3期31卷 912-929页

作者：赵宏刚张东明蒋长宝李铭辉 Chongqing key laboratory of Geomechanics&Geoenvironmental Protection Department of Military InstallationsArmy Logistics Academy of PLAChongqing 401311China State key laboratory of Coal mine disaster Dynamics and control Chongqing UniversityChongqing 400030China School of Resources and Safety Engineering Chongqing UniversityChongqing 400030China Institute of Deep Earth Sciences and Green Energy College of Civil and Transportation EngineeringShenzhen UniversityShenzhen 518060China

深埋地下工程的开挖导致隧洞径向方向围岩内部存在梯度应力。基于此,本文研究了梯度应力条件下围岩在不同轴向应力作用下的力学响应和断裂特征,并且在试验过程中,采用声发射(AE)系统采集了岩石破裂声发射信号。结果表明:梯度应力作用下... 详细信息

深埋地下工程的开挖导致隧洞径向方向围岩内部存在梯度应力。基于此,本文研究了梯度应力条件下围岩在不同轴向应力作用下的力学响应和断裂特征,并且在试验过程中,采用声发射(AE)系统采集了岩石破裂声发射信号。结果表明:梯度应力作用下,轴向应力对砂岩力学响应的影响与经典真三轴压缩试验结果相似。当轴向应力小于临界强度时,随着轴向应力的增大,砂岩特征应力逐渐增大,显著提高了砂岩承载能力。但是当轴向应力超过临界强度时,高轴向应力的加载过程会导致砂岩产生局部破坏,引起砂岩特征应力的降低,此时,砂岩内部仅有部分裂纹合并贯通,形成斜向宏观裂隙,但并未贯穿整个砂岩试样。声发射特征信号分析结果表明,随着轴向应力的增大,砂岩在破坏过程中产生的剪切裂纹比例逐渐减小,拉伸裂纹在整个新生裂纹中占据主导地位,并控制着砂岩的破坏。这反映了在梯度应力条件下,随着轴向应力的增大,围岩内部因微观拉伸裂纹合并而形成宏观剪切裂纹的活动会受到明显的抑制作用。

关键词：梯度应力轴向应力声发射特征应力拉伸裂纹

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Pollution characteristics and source apportionment of heavy metal(loid)s in soil and groundwater of a retired industrial park

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Journal of Environmental Sciences 2024年第9期143卷 23-34页

作者： Zijing Xiang Shijin Wu Lizhong Zhu Kun Yang Daohui Lin Zhejiang Provincial key laboratory of Organic Pollution Process and control Department of Environmental SciencesZhejiang UniversityHangzhou 310058China Zhejiang Ecological Civilization Academy Anji 313300China

Heavy metal(loid)s(HMs)pollution has become a common and complex problem in industrial parks due to rapid industrialization and ***,soil and groundwater were sampled from a retired industrial park to investigate the pollution characteristics of *** show that Ni,Pb,Cr,Zn,Cd,and Cu were the typical HMs in the *** analysis with the positive matrix factorization model indicates that HMs in the topsoil stemmed from industrial activities,traffic emission,and natural source,and the groundwater HMs originated from industrial activities,groundwater-soil interaction,groundwater-rock interaction,and atmosphere *** sequential extraction of soil HMs reveals that As and Hg were mainly distributed in the residue fraction,while Ni,Pb,Cr,Zn,Cd,and Cu mainly existed in the mobile *** HMs either in the total concentration or in the bioavailable fraction preferred to retain in soil as indicated by their high soil-water partitioning coefficients(K_(d)),and the K_(d) values were correlated with soil pH,groundwater redox potential,and dissolved *** relative stable soil-groundwater circumstance and the low active fraction contents limited the vertical migration of soil HMs and their release to *** findings increase our knowledge about HMs pollution characteristics of traditional industrial parks and provide a protocol for HMs pollution scrutinizing in large zones.

关键词： Heavy metal(loid)s Industrial park Source apportionment Chemical fraction Soil-groundwater partitioning

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Vibration reduction effect of the shielding pile based on seismic wave attenuation in shallow underground spaces

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Journal of Earth Science 2024年

作者： Qiankuan Wang Shili Qiu Aiguo Xing Xueyong Xu Ye Zhou Yao Cheng Haoshan Zhang Bo Wu Yiwei Liu Mingzhe Zhang Yu Zhuang State key laboratory of Ocean Engineering， Shanghai Jiao Tong University State key laboratory of Geomechanics and Geotechnical Engineering， Institute of rock and Soil Mechanics， Chinese Academy of Sciences North Information control Research Academy Group CO.， LTD Faculty of Engineering， China University of Geosciences

Seismic hazards threaten underground structures and subsequently affect surface buildings， making effective vibration reduction measures crucial in shallow underground spaces. This paper proposes a multi-layer shielding pile based on the seismic wave attenuation theory of refraction dispersion and diffraction loss as a new vibration reduction method. By using the dynamic wave interaction between the unique multi-layer structure of the shielding pile and the seismic wave， a shielding area with significant attenuation of the ground motion is formed to achieve the purpose of vibration reduction. The spectral element method (SEM) with high-order source time function and convolution perfect matching layer (PML) is used to simulate the numerical models of shielding piles with different parameters (including background models and excavation models)， and the characteristics of ground motion and site effect near shielding piles in various models are analyzed. The study reveals the control effect and regulation of the material， size， and shape of the shielding pile on its vibration reduction effect， and determines the shielding pile parameters with the best vibration reduction effect. Shielding piles enriches the vibration reduction measures for structures in shallow underground spaces， and provides a new method for preventing seismic hazards under dynamic load.

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rock mechanical characteristics and landscape evolutionary mechanism of the slit-type Danxia landform on the Chinese Loess Plateau

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Journal of Arid Land 2024年第10期16卷 1327-1343页

作者： MEN Huan DING Hua DENG Yahong MU Huandong HE Nainan SUN Pushuo LI Zhixu LIU Yan School of Geology Engineering and Geomatics Chang'an University School of Architecture Chang'an University Shaanxi Academy of Yellow River Sciences Institute of Tourism Planning and Design Chang'an University key laboratory of mine Geological Hazards Mechanism and control Ministry of Natural Resources

Since 2015, the newly discovered slit-type Danxia landform on the Chinese Loess Plateau has become a hot topic in the field of geomorphology worldwide. However, the relationships among its formation, evolutionary mechanism, and mechanical characteristics of its strata and rocks are not clear. In this paper, the Ganquan canyon group is used as the research object. Basic physical and mechanical indices of sandstone in the Ganquan canyon group were measured through field investigation and indoor experiments, and the deterioration trends for the mechanical parameters of sandstone in this area under the action of infiltration, acid dry-wet cycles, and freeze-thaw cycles were revealed. Lastly, the formation and evolutionary mechanism of the slit-type Danxia landform were discussed. The results showed that:(1) The sandstone in the canyon group had a low cementation degree and weak cohesive force, which was easily weakened under the action of water, resulting in a decrease in compressive strength and elastic modulus.(2) Acidic dry-wet cycles caused the mineral composition of the sandstone to be dissolved, and the micropores continued to grow and develop until new cracks were produced. Macroscopically, the compressive strength and elastic modulus of sandstone were greatly reduced, and this damage was cumulative and staged. The greater the acidity, the greater the damage.(3) As the number of freeze-thaw cycles increased, the uniaxial compressive strength and elastic modulus of the sandstone decreased continuously. During the freeze-thaw cycle process, the growth and development of cracks were primarily in fracture mode and usually developed along parallel bedding positions.(4) The interaction of tectonic activity and lithology with different weathering processes was a key factor in the formation and evolution of the slit-type Danxia landform. In conclusion, the intricate process of weathering influenced by historical climatic fluctuations has been pivotal in shaping the topog

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