摘要：
This paper presents a theoretical solution for bond-slip behavior of SRC interface based on experiment, numerical simulation, and theoretical derivation. Push-out tests of five specimens were firstly carried out, based on which, the simplified bond-slip model was proposed. The specimen was fabricated using the Q345H-shape steel (400 mm x 200 mmx13 mm x 8 mm) and C50 concrete (350 mm x 600 mm) with a bonding length of 500 mm. A FE model was established based on the bond-slip model to analyze the nonlinear bonding stress that are difficult to obtain from the experiment. The research shows that although the bonding stress in the elastic stage is not uniformly distributed, it is basically uniformly distributed when the ultimate bearing capacity is reached. It proves that assuming the average interfacial bonding stress under ultimate load to replace the maximum bonding stress is reasonable, which is crucial for designer to estimate interface bearing capacity and maximum bonding stress. Moreover, five different stages were obtained by the FE model analysis and the theoretical equations of bonding stress nonlinear distribution were obtained based on the boundary condition of each stage. The theoretical solution clearly showed the relationship between interface nonlinear stress distribution and influencing parameters including the bond area, elasticity modulus of material, section area of specimen, bond-slip constitutive model, and the external load. Based on the theoretical model, the influences of different parameters can be directly obtained without conducting further experiments and establishing different FE models.
期刊：
Separation and Purification Technology,2024年335:126214 ISSN：1383-5866
通讯作者：
Xie, D
作者机构：
[Li, Suzhe; Tang, Zengming; Yang, Xiaomin] Univ South China, Sch Resource & Environm & Safety Engn, Hengyang 421001, Peoples R China.;[Xie, D; Xie, Dong; Li, Suzhe; Tang, Zengming; Yang, Xiaomin] Natl & Local Joint Engn Res Ctr Airborne Pollutant, Hengyang 421001, Peoples R China.;[Xie, D; Xie, Dong] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Xie, D ] N;Natl & Local Joint Engn Res Ctr Airborne Pollutant, Hengyang 421001, Peoples R China.;Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.
摘要：
Finding an inexpensive and efficient porous adsorbent to capture the gaseous radioiodine generated during spent fuel reprocessing has been challenging. Herein, we present a design philosophy for waste control to develop porous carbon for gaseous iodine capture from sewage sludge waste. Among them, the novel in situ etching of polytetrafluoroethylene was employed to improve pore accessibility. The hazards of the conventional preparation of sludge-derived carbon using highly corrosive NaOH and HF solutions were overcome. Polytetrafluoro-ethylene etched porous carbon with large specific surface area (1103 m2/g), interconnected hierarchical porous structure, and excellent hydrophobicity (water contact angle 126.52 degrees), providing efficient adsorption of gaseous iodine in hot (30-150 degrees C) and humid (50-96% relative humidity [RH]) environments. The iodine adsorption of hierarchical porous carbon was tested under static and dynamic conditions, and high records have been achieved. Notably, due to the structural advantage of hydrophobicity, a considerable dynamic adsorption capacity (1746.77 mg/g) was also maintained in a mixed iodine gas stream containing water vapor in a humid (50% RH) hot (75 degrees C) condition. This study is the first to use an in situ etching strategy for polytetrafluoroethylene, which opens a new avenue for converting sludge waste into low-cost porous carbon and provides an attractive option for capturing iodine in hot and humid environments.
期刊：
Theoretical and Applied Climatology,2024年155(1):117-129 ISSN：0177-798X
通讯作者：
Wang, HQ
作者机构：
[Wang, HQ; Liu, Xinyu; Wang, Hanqing; Zhu, Dongnan; Liu, Zhenming; He, Junyi] Univ South China, Sch Civil Engn, Hengyang, Peoples R China.;[Wang, HQ; Liu, Xinyu; Wang, Hanqing; Zhu, Dongnan; Liu, Zhenming; He, Junyi] Natl & Local Joint Engn Res Ctr Airborne Pollutant, Hengyang, Peoples R China.;[Wang, HQ; Wang, Hanqing] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha, Peoples R China.
通讯机构：
[Wang, HQ ] U;Univ South China, Sch Civil Engn, Hengyang, Peoples R China.;Natl & Local Joint Engn Res Ctr Airborne Pollutant, Hengyang, Peoples R China.;Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha, Peoples R China.
关键词：
WRF;Deep learning;Downscaling
摘要：
The Weather Research and Forecasting (WRF) model improves the accuracy of climate prediction and obtains meteorological parameters for fine grids; however, fine-grid climate predictions for different time periods and regions often consumes a great amount of computational resources. In this letter, the Multi Residual Attention Generative Adversarial Network (MRA-GAN) is proposed based on the generative adversarial network; the technique is applied to restore a simulated image from a coarse-grid WRF model to a simulated image from a fine-grid WRF model. The fine-grid image generated by MRA-GAN is very similar to the original fine-grid image. When compared with Super-Resolution Wasserstein Generative Adversarial Network with Gradient Penalty (SRWGAN-GP), the average of peak signal-to-noise was improved by approximately 0.54dB, and the average structural similarity index was improved by approximately 3%. After comparing the downscaling results of temperature, wind speed, and relative humidity of various models with the original data, the results show that MRA-GAN has the highest correlation, the lowest data dispersion, and the smallest data error. The trained network model was able to efficiently transform the coarse-grid meteorological fields from different time periods and different simulation variables into fine-grid meteorological fields, and it greatly reduced the computational workload.
摘要：
Mining can provide abundant resources, but it also causes heavy metal wastewater pollution, which poses a serious threat to aquatic ecosystems. In this study, Cypridopsis vidua was used as the test organism to investigate the single and combined acute toxicity of common heavy metals (such as chromium (Cr) and nickel (Ni)) in mining wastewater. Then, a random forest model (RF model) was used to predict the combined toxicity of chromium and nickel. Single acute toxicity experiments showed that the 96 h-LC(50 )values of the Cr and Ni for Cypridopsis vidua were 0.81 mg/L and 4.3 mg/L, respectively. aCr was more toxic than Ni. Furthermore, the combined acute toxicity experiments demonstrated that the toxicity of Cr-Ni was higher than Ni but lower than Cr. The predicted results of the RF model were highly consistent with the experimental results of the Cr-Ni combined acute toxicity. So, the model has accurate toxicity prediction ability.
摘要：
To investigate the strengthening effects and mechanisms of bioaugmentation on the microbial remediation of uranium-contaminated groundwater via bioreduction coupled to biomineralization, two exogenous microbial consortia with reducing and phosphate-solubilizing functions were screened and added to uranium-contaminated groundwater as the experimental groups (group B, reducing consortium added; group C, phosphate-solubilizing consortium added). β-glycerophosphate (GP) was selected to stimulate the microbial community as the sole electron donor and phosphorus source. The results showed that bioaugmentation accelerated the consumption of GP and the proliferation of key functional microbes in groups B and C. In group B, Dysgonomonas, Clostridium_sensu_stricto_11 and Clostridium_sensu_stricto_13 were the main reducing bacteria, and Paenibacillus was the main phosphate-solubilizing bacteria. In group C, the microorganisms that solubilized phosphate were mainly unclassified_f_Enterobacteriaceae. Additionally, bioaugmentation promoted the formation of unattached precipitates and alleviated the inhibitory effect of cell surface precipitation on microbial metabolism. As a result, the formation rate of U-phosphate precipitates and the removal rates of aqueous U(VI) in both groups B and C were elevated significantly after bioaugmentation. The U(VI) removal rate was poor in the control group (group A, with only an indigenous consortium). Propionispora, Sporomusa and Clostridium_sensu_stricto_11 may have played an important role in the removal of uranium in group A. Furthermore, the addition of a reducing consortium promoted the reduction of U(VI) to U(IV), and immobilized uranium existed in the form of U(IV)-phosphate and U(VI)-phosphate precipitates in group B. In contrast, U was present mainly as U(VI)-phosphate precipitates in groups A and C. Overall, bioaugmentation with an exogenous consortium resulted in the rapid removal of uranium from groundwater and the formation of U-phosphate minerals and served as an effective strategy for improving the treatment of uranium-contaminated groundwater in situ.
期刊：
Applied Radiation and Isotopes,2024年205:111145 ISSN：0969-8043
通讯作者：
Xie, SB
作者机构：
[Xie, Shuibo; Mai, Yingqing; Wang, Guohua; Zhang, Haibo] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Xie, Shuibo] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Min, Hengyang 421001, Peoples R China.;[Wang, Shuiyun] Nonferrous Met Design & Res Inst, Changsha 410000, Peoples R China.;[Xie, Shuibo] Univ South China, 28 Changshen Rd, Zhengxiang Dist, Hengyang 421001, Peoples R China.
通讯机构：
[Xie, SB ] U;Univ South China, 28 Changshen Rd, Zhengxiang Dist, Hengyang 421001, Peoples R China.
关键词：
Acid wastewater;Adsorption;PT-CS;U(VI)
摘要：
With sodium tripolyphosphate (STPP) as cross-linker, Persimmon tannin-chitosan microspheres (PT-CS) were synthesized by hydrothermal for removing U(VI) from acidic effluent. The batch experiments indicated that PT-CS adsorbed U(VI) most effectively at pH 1.5, the maximum adsorption capacity for PT-CS was 245mg/g. Compared to pure CS dissolved at pH 3, PT-CS still maintain high stability at pH 1. Moreover, single system of common metal ions in rare earth wastewater only slightly affected the adsorption of uranium at pH 1.5, but this process was inhibited about 30% at pH 5. Those results indicated that the selectivity of PT-CS for uranium removal could be controlled by regulating the pH and there are excellent potentials for PT-CS using in acid metal water treatment. Its adsorption selectivity and ability to adapt different condition was demonstrated with uraniferous rare earth wastewater treatment. The adsorption for PT-CS to U(VI) were well fitted for both Langmuir isothern and pseudo-secondary kinetic model equations, and that meant chemisorption dominated the removal process. Spectroscopic analyses confirmed that the adsorption of U(VI) occurred via surface complexation by -OH and ion exchange with Na(+). Therefore, this study provides a high-efficiency, low-cost, valuable and highly adaptable method for the treatment of acidic uranium-containing effluents.
通讯机构：
[Zeng, S ] U;Univ South China, Sch Resource Environm & Safety Engn, Hengyang 421001, Peoples R China.
关键词：
Anchor bolts;Pull-out load;Cement-sand ratio;Anchorage defect;Key dynamic testing signal
摘要：
Pull-out load and the cement -sand ratio (CSR) can affect the non-destructive testing (NDT) results of anchor bolts. Therefore, in this article, NDT experiments were conducted on both fully and defectively grouted anchor bolts, and variation patterns of key dynamic testing signal parameters were analyzed. A longitudinal vibration model of defectively grouted anchor bolts considering dynamic and static damping was proposed, and simulated NDT of anchor bolts with varying qualities. The results indicated that grouting defects resulted in an increase in wave velocity, along with a decrease in the fundamental frequency and dynamic stiffness of anchor bolts. When grouting defects and pull-out load acted concurrently, the fundamental frequency, and dynamic stiffness of the defectively grouted anchor bolts were consistently smaller than those of fully grouted ones during the initial loading phase. With pull-out load increasing, wave velocity decreased first, then increased; fundamental frequency increased, followed by a decrease; dynamic stiffness rose. When the CSR of defectively grouted anchor bolts was reduced, wave velocity decreased, fundamental frequency increased slightly, and a substantial increase in dynamic stiffness was observed. Pull-out loads were more sensitive to anchor bolt key dynamic signals than defects and CSR. Simulated validation demonstrated the reliability of the proposed theory.
摘要：
Levels of cadmium (Cd) and lead (Pb) correspond to common composition in acid mine wastewater of Hunan Province of China. The removal path of Cd and Pb and the structure of microbial community were investigated by developing constructed wetlands (CWs) with different layer positions of biochar. The biochar as a layer at the bottom of CW (BCW) system exhibited maximum Cd and Pb removal efficiencies of 96.6-98.6% and 97.2-98.9%, respectively. Compared with original soil, BCW increased the relative proportions of Proteobacteria, Firmicutes, Acidobacteriota, Verrucomicrobiota, Desulfobacterota, Armatimonadota, Bacteroidota, Patescibacteria, Basidiomycota (phylum level) and Burkholderia-Caballeronia-Paraburkholderia, Citrifermentans, Chthonomonadales, Cellulomonas, Geothrix, Terracidiphilus, Gallionellaceae, Microbacterium, Vanrija, Apiotrichum, Saitozyma, Fusarium (genus level). The concentrations of Cd and Pb were positively correlated with the abundance of Verrucomicrobiota, Basidiomycota (phylum level), and Methylacidiphilaceae, Meyerozyma, Vanrija (genus level). This study demonstrates that BCW system can improve removal performance toward Cd and Pb, as well as alter microbial community.
摘要：
In this study, we employed classic electrochemical techniques including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) to perform electrochemical characterization on atomic-level single-crystal TiO2 electrodes and extract capacitive and resistive properties of single-crystal TiO2 electrode/solution interface in KCl and KCl/K3PO4 at various pH levels. The lattice structure and crystal appearance were characterized using X-ray diffractometry (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy to facilitate the in-depth exploration of heterogeneous reaction dynamics and theory. Furthermore, this study aimed to verify and improve the theory and application of capacitance at the single-crystal TiO2 electrode/solution interface. The electrochemical measurements indicate that, in the same pH, the presence of PO43- significantly increases the total capacitance (C-T), outer capacitance (C-O), electrical double-layer capacitance (C-dl), and diffusion layer capacitance (C-diff) at single-crystal TiO2 electrode/solution interface. This enhancement is attributed to the direct interaction between PO43- and the single-crystal TiO2 electrode surface, leading to the specific adsorption of PO43- on the electrode surface, revealing higher current and stronger electrochemical activity in the interaction between TiO2 and PO43-. Additionally, our XPS results indicate the adsorption of PO43- on the single-crystal TiO2 electrode surface. The interaction of PO43- with the TiO2 surface demonstrates increased hydrophilicity and enhanced adsorption capacity through mechanisms such as ligand exchange or cation bridging, thereby augmenting the C-dl at the single-crystal TiO2 electrode/solution interface.
摘要：
Thermal-mechanical damage is an important problem threatening the safety of deep rock engineering. In this paper, the effects of coupling damage on the deformation and failure characteristics of rock mass were studied via cyclic loading damage, thermal damage and uniaxial compression acoustic emission (AE) tests, and the microscopic fracture process of the damaged rock mass was numerically simulated. Results showed that during heat treatment, the colour of the sample changed significantly, the mass, the P-wave velocity and the number of mineral species decreased. The peak strength and elastic modulus reach their maximum values at 600 degrees C and 300 degrees C, respectively, exhibiting a trend of initial increase and subsequent decrease. The rapid growth period of AE activity increased noticeably with increasing temperature, and the effect of energy accumulation became more significant at higher peak strengths. The failure mode was influenced primarily by the cyclic loading amplitude. In addition, an increase in the stress or temperature after crack initiation leads to a sharp increase in the damage within the rock. Temperature had a more significant effect on the generation of damage than stress. Stress-induced microcracks were concentrated in the weakly bonded particles, whilst temperature-induced microcracks were concentrated in the strongly bonded particles. Temperature had a significant effect on the mineral composition of rock mass.The rapid growth period of AE activity was prolonged with the temperature increase.The failure mode of rock mass was mainly influenced by cyclic loading amplitude.Temperature-induced microcracks were concentrated in strongly bonded particles.
摘要：
The reduction of soluble U(VI) to insoluble and less toxic U(IV) by photocatalysis is an effective method to control uranium contamination. The graphitic carbon nitride nanosheet (CNN)/UiO-66 composites (CNNU) were prepared by thermal polymerization and solvothermal methods for the removal of U(VI). The morphology, crystal structure and optical properties of composites were analyzed by SEM, XRD, BET, UV-DRS, PL and EIS. The results showed the introduction of UiO-66 increased the specific surface of CNN from 9.07 m(2)/g to 46.24 m(2)/g, and effectively suppressed the recombination of photogenerated electrons and holes and improved the photocatalytic activity. The U(VI) removal capacity by adsorption and photocatalysis of CNNU was reached 779.47mg/g, which significantly higher than that of adsorption (478.38mg/g). The adsorption process was found to conform to the pseudo-second-order kinetic model and the Langmuir isothermal model. Meanwhile, U(VI) adsorbed on the CNNU was reduced to U(IV) via e(-) and ·O(2)(-) generated in the photocatalytic process. Therefore, this outstanding performance of CNNU in U(VI) removal is attributed to the synergistic effect of adsorption and photocatalytic reduction.
期刊：
Measurement Science And Technology,2023年34(6) ISSN：0957-0233
作者机构：
[Xie, Shuibo; Liao, Yanguo] Univ South China, Sch Resource Environm & Safety Engn, Hengyang 421001, Peoples R China.;[Liao, Yanguo] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Xie, Shuibo] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.
关键词：
transversely isotropic materials;cylindrical indentation;elastic parameters;dimensional analysis;finite element (FE);three-dimensional (3D)
摘要：
Based on the cylindrical indention experiments, a novel model has been established to characterize the elastic mechanical property of transversely isotropic materials. In the first place, the influences of different loading orientations for indentation, and elastic parameters of materials on the indentation modulus of transversely isotropic materials are analyzed by means of theoretical and dimensional analysis. In the second place, three dimensional (3D) indentation experiments that encompass the wide range of transversely isotropic material parameters are simulated by finite element (FE) approach. Each quantity (transversely isotropic Young's modulus, EP, longitudinal Young's modulus, EL, longitudinal shear modulus, GL, and loading orientation angle, ) how affects the normalized indentation modulus is investigated. Then, the dimensionless analytical relationship between indentation modulus and elastic parameters is put up at three different indentation orientation angles . To prove the correctness of the proposed model, several groups of transversely isotropic materials are selected as input parameters to carry out indentation numerical experiments and the error analysis is made in detail. Simultaneously, the technique is specialized to the particular case of a Zinc single crystal material to verify the accuracy of these formulas derived. These good agreements show that the proposed method is reliable and it could be used to quantify the elastic parameters of the transversely isotropic materials.
摘要：
The thermal effect of electrokinetic remediation (EKR) is a kind of energy dissipation, which is an important part of the useless work in the process of EKR. Therefore, this study aims to reveal the phenomenon and mechanism of thermal effect and the energy distribution mechanism in the process of EKR. To explore the distribution mechanism of soil temperature during the EKR process, nine groups of orthogonal EKR experiments lasting 120 h were carried out. The experimental results show that the phenomenon of thermal effect is common in the process of electric remediation of uranium pollution, and it is positively correlated with the current of the system. At the same time, soil pH, moisture, and conductivity are all related to soil temperature. According to the range analysis, the voltage gradient has the greatest impact on the current utilization rate. Under the conditions of 0.5 V/cm and 0.5 mol/L citric acid (CA), the maximum removal efficiency of U(VI) in the soil is 36.58%, and the maximum current utilization rate eta is 3.85%. In general, the study of the general law of thermal effect in the process of EKR will provide theoretical support for weakening the effect of thermal effect, avoiding wasting more energy, improving the utilization efficiency of energy, and transforming the EKR process. Therefore, this study has a positive significance for the law of thermal effect in the process of EK and the engineering application of EKR technology. Highlights center dot Current utilization efficiency and energy distribution mechanisms were discovered during the EKR process. center dot The distribution mechanism of temperature in soil cell was revealed in the EKR process. center dot Optimizing experimental combination, providing a theoretical basis for engineering practical application.
作者机构：
[Fan, Junwei; Sun, Bing; Yang, Haowei] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Liu, Xiling] Cent South Univ, Sch Resources & Safety Engn, Changsha 410083, Peoples R China.;[Zeng, Sheng] Univ South China, Sch Resources Environm & Safety Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Sheng Zeng] S;School of Resources Environment and Safety Engineering, University of South China, Hengyang 421001, China<&wdkj&>Author to whom correspondence should be addressed.
关键词：
rock mechanics;cyclic loading and unloading;acoustic emission;energy evolution;damage characteristic;ultimate damage energy
摘要：
In order to study the deformation and failure characteristics of rocks under different cyclic loading and unloading paths, three stress path tests were conducted, and acoustic emission (AE) monitoring was conducted simultaneously. The mechanical characteristics and AE characteristics under different stress paths were analyzed, and the influences of the different stress paths on the energy dissipation and deformation damage were investigated. The law of energy evolution considering viscoelasticity under different stress paths was obtained. The concept of ultimate damage energy and its calculation method was proposed. The results show that the “hardening effect” of sandstone and granite under the constant lower limit (CLLCL) is the most significant in maximizing the mechanical property. The CLLCL imparts a stronger elastic property to rocks than the variable lower limit (VLLCL) does, while the VLLCL causes more damage to rocks than the CLLCL. A significant linear relationship between the proportion of damage energy and the proportion of elastic energy was discovered. Based on this linear relationship, the ultimate damage energy can be calculated for sandstone and granite. The evolution of the damage variable based on damage energy was compatible with the real damage condition, which validates the ultimate damage energy calculation method. The research results lay a theoretical foundation for the design and construction of geotechnical engineering.
期刊：
Geomechanics and Geophysics for Geo-Energy and Geo-Resources,2023年9(1):1-18 ISSN：2363-8419
通讯作者：
Xie, HP
作者机构：
[Hu, Guibo; Zhou, Changtai; Xie, Heping; Luo, Junhan; Zhang, Kai; Zhu, Jianbo] Shenzhen Univ, Inst Deep Earth Sci & Green Energy, Guangdong Prov Key Lab Deep Earth Sci & Geothermal, Shenzhen 518060, Peoples R China.;[Hu, Guibo; Zhou, Changtai; Luo, Junhan; Zhang, Kai; Zhu, Jianbo; Xie, Heping] Shenzhen Univ, State Key Lab Intelligent Construct & Hlth Operat, Shenzhen 518030, Peoples R China.;[Guo, Wei] Cent South Univ, Natl Engn Res Ctr High Speed Railway Construct Tec, Sch Civil Engn, Changsha 410075, Peoples R China.;[Qiu, Jiadong] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Xie, HP ] S;Shenzhen Univ, Inst Deep Earth Sci & Green Energy, Guangdong Prov Key Lab Deep Earth Sci & Geothermal, Shenzhen 518060, Peoples R China.
关键词：
Tunnel;Train moving load;Physical model experiment;Peak particle velocity;Vibration dominant frequency
摘要：
The tunnels might be suffered from damage and destruction under the dynamic loads generated by trains moving on the upper railways, which can in turn threaten the safety of the railways. Understanding the dynamic response of tunnel under the train moving load is of significance for maintaining the operation safety of both the tunnel and upper railway. However, there is currently a lack of relevant research on this topic, especially regarding model experiments. To address this gap, this paper conducts physical model experiments on the train-rail-bridge-shaking table test system to investigate the dynamic response of tunnels subjected to train moving load. The experiment results revealed that except for the average peak particle velocity (PPA) at tunnel vault, the average PPAs at other locations and the vibration dominant frequency (f0) at all locations increase as the train moving speed (vtr) increases. With the exception of some special cases, the average PPAs on tunnel spandrels are generally less than that on the tunnel vault and greater than that on the tunnel invert. When the vtr exceeds 7.03 m/s, except for the average PPA at tunnel invert, the average PPAs on the tunnel wall are generally larger than those inside the surrounding rock mass. As vtr increases, the average f0 on tunnel wall changes more obviously compared to average f0 inside the surrounding rock mass. When the vtr exceeds 10.54 m/s, the average f0 on tunnel wall are noticeably larger than those inside the surrounding rock mass. The high coefficients of determination obtained from the nonlinear regression analysis indicates a power relationship between the average PPA and vtr, while the average f0 shows an exponential association with vtr. The research findings hold great importance in ensuring the safe operation of tunnels and railways. Physical model experiments were conducted on the train-rail-bridge-shaking table test system, where train moving load was applied through moving of a model train along model tracks. The effects of train moving speed on the particle acceleration and vibration frequency on the tunnel wall and inside the surrounding rock mass were investigated.The relationships between train moving speed and peak particle acceleration, as well as vibration dominant frequency were established using nonlinear regression analysis.
期刊：
Energy and Buildings,2023年279:112704 ISSN：0378-7788
通讯作者：
Hui Zhu
作者机构：
[Zhu, Hui; Hu, Songtao; Wang, Haiying] Qingdao Univ Technol, Sch Environm & Municipal Engn, Qingdao 266520, Peoples R China.;[Hu, Mingle] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Guan, Jinsheng] Hunan Chuangxinweili Technol Co Ltd, Changsha 410000, Peoples R China.
通讯机构：
[Hui Zhu] S;School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, China
关键词：
Accuracy;Cognitive performance;Hot-humid exposure;Mean skin temperature;Response time
摘要：
Compromised cognitive performances under hot and humid environment have been widely reported in recent years, as the extreme climate events come more frequently and intensively. In order to evaluate the cognitive performance under hot-humid exposure, the skin temperature, core temperature and the heart rate of 14 right-handed male participants were measured when they were conducting 5 different kinds of cognitive tasks under hot-humid environments at 32, 35, 38, 41 degrees C and RH 70 %. Each session consisted of these 5 tasks with different orders followed the Latin Square Design. And the session was repeated in the whole experiment till each participant refused to continue. Results showed that the mean skin temperature (Tmsk) increased during the hot-humid exposures, which was attributed to the air temperatures and the exposure time. Furthermore, the mean accuracy and response time of these tasks were negatively related with each other. A U-shape relation between the Tmsk and mean accuracies was observed, while an Inverted-U relation between the Tmsk and the mean response time was detected. Finally, a 4th order-function paradigm was acquired between the Tmsk and the relative cognitive performance (RCP). In terms of the results, the small Tmsk range from 36.0 degrees C to 37.25 degrees C was presented, within which the stable RCP were observed, while out of which the RCP deteriorated. The findings provided a potential solution for the evaluation of the cognitive performance under hot-humid exposures.(c) 2022 Elsevier B.V. All rights reserved.
摘要：
In this paper, quaternary hydrotalcite [layered double hydroxide (LDH)] (CoFeMgAl-LDH) was first fabricated based on the coprecipitation method, and then, CoFeMgAl-LDH/carbon nanotubes (CNTs) composite was synthesized by CNTs and CoFeMgAl-LDH through the solid phase mixing method. Subsequently, the physical-chemical properties of CoFeMgAl-LDH/CNT composite were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, energy dispersive spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) analysis. Meanwhile, the performance of CoFeMgAl-LDH/CNT composite for SO2−4 SO42− adsorption was evaluated under different conditions, including different initial concentration, contact time, adsorbent dosage, solution pH, temperature, and coexisting ions. Afterward, the SO2−4 SO42− adsorption capacity of CoFeMgAl-LDH/CNT in cement paste was further studied. The results showed that the CoFeMgAl-LDH/CNT composite exhibited a three-dimensional structure with high specific surface area. The maximum SO2−4 SO42− adsorption amount of the CoFeMgAl-LDH/CNT composite was 116.27 mg/g 116.27 mg/g , which was significantly higher compared with other absorbents of the same type. Pseudosecond-order kinetic model could reasonably describe the adsorption kinetics, and Freundlich isotherm could fit the adsorption data accurately. The results also suggest that the synthesized CoFeMgAl-LDH/CNT composite can serve as a potential material for the sulfate binding in cementitious materials.
作者机构：
[Ou, Jinchen; Hei, Fuqian; Liu, Qing; Xu, Fei] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Ou, Jinchen; Hei, Fuqian; Liu, Qing; Xu, Fei] Hunan Prov Key Lab High Performance Special Concre, Hengyang 421001, Peoples R China.;[Zhao, Guodong] Univ South China, Sch Resourse Environm & Safety Engn, Hengyang 421000, Peoples R China.
通讯机构：
[Qing Liu] S;School of Civil Engineering, University of South China, Hengyang 421001, China<&wdkj&>Hunan Provincial Key Laboratory of High Performance Special Concrete, Hengyang 421001, China<&wdkj&>Author to whom correspondence should be addressed.
摘要：
Polyaluminum chloride slag produced in the production of water treatment agents pollutes the environment and wastes land resources in the process of landfill and waste. In order to solve the resource waste of researching polyaluminum chloride slag, it was used to prepare sintered bricks. In this study, sintered bricks were prepared from polyaluminum chloride slag and glass powder. Taking compressive strength, water absorption, linear shrinkage and bulk density as measurement indexes, the effects of the glass powder content (0-10 wt%), molding moisture (10-20%), molding pressure (15-27.5 MPa), heating method (heat preservation at 400 degrees C and 1000 degrees C for 2 h, heat preservation at 500 degrees C and 1000 degrees C for 2 h, and heat preservation at 1000 degrees C for 2 h), heating rate (2-10 degrees C/min) and sintering temperature (900-1100 degrees C) on the performance of sintered brick and the conditions for meeting Chinese standards were studied. Then, the sintered bricks prepared at different temperatures were characterized by X-ray diffraction and scanning electron microscopy. The results show that the compressive strength (bulk density) increases and the water absorption decreases with the increase of the glass powder content, molding pressure, molding moisture and sintering temperature. Moreover, the linear shrinkage increases with the increase of the molding pressure, molding moisture and sintering temperature, but decreases with the increase of the glass powder content. When the glass powder content of the sintered brick is 10 wt%, with molding moisture of 20 wt%, molding pressure of 25 MPa, heating mode to directly raise the temperature to the target temperature, heating speed of 10 degrees C/min and sintering temperature of 1100 degrees C, the properties, pH value and leaching toxicity of sintered bricks meet the requirements of Chinese standard brick MU15. XRD and SEM analyses showed that with the increase of the sintering temperature, new albite and amphibole phases were formed in the structure, and quartz and other silicate minerals melted to form a liquid phase, making the structure more compact and the performance better. The research results provide a reference for the comprehensive utilization of polyaluminum chloride slag.
