摘要：
End-anchors have been widely used to prevent/postpone debonding failures in FRP-strengthened RC structures. The bond behavior between FRP and concrete with end-anchors can be investigated through FRP-concrete bonded joint with such anchors. Existing studies have found that deformation of FRP and the anchor, as well as slip of FRP-concrete interface at the anchored end can happen when the FRP is under external loading; therefore, the simple assumption that end-anchors provide a rigid end to FRP may result in significant over-estimations of the bonding stiffness and strength. Against this background, this paper presents an analytical study on the closed-form solution to the full-range bond behavior of CFRP-concrete bonded joint with a non-rigid anchor. The obtained analytical solution was first verified through finite element analyses and test results, and then was adopted in a comprehensive parametric study to investigate the effect of mechanical properties of end-anchors on the overall bond behavior of the joint. This paper provides a better understanding of the bond behavior between FRP and concrete with a non-rigid anchor and shows that the design of such end-anchors should be based on CFRP-concrete interfacial characteristics for a desired bond behavior.
期刊：
Journal of Cleaner Production,2023年412:137384 ISSN：0959-6526
通讯作者：
Yi, X
作者机构：
[Yi, Xin; Liu, Mocun; Li, Shuangshuang; Lu, JiaHui] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha 410004, Peoples R China.;[Qiu, Hui] Cent South Univ Forestry & Technol, Sch Landscape Architecture, Changsha 410004, Peoples R China.
通讯机构：
[Yi, X ] C;Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha 410004, Peoples R China.
关键词：
Construction waste recycling;Non -market valuation;Contingent valuation method;Degree of uncertainty;Willingness to pay
摘要：
Construction Waste Recycling (CWR) has a significant non-market valuation, such as conserving land resources, improving air and water quality. However, it's valuation has not been widely explored. This study aims to reasonably estimate the CWR non-market valuation by taking Changsha, China as an example. To get more reliable and accurate estimating result, an improved Card Ladder CVM (CL-CVM) has been put forward, which included the advantages of both continuous CVM (CCVM) and discrete CVM (DCVM). Subsequently, an extra question captured the degree of uncertainty of urban residents and construction contractors regarding CWR, and influencing factors were also investigated by 1127 valid urban residents' respondents and 116 of construction contractors face-to-face. The key findings are as follows: (1) Only 12.87% of urban residents' respondents, and Only 6.90% of construction contractors' respondents wouldn't be willing to pay for CWR, and the total non-market valuation of CWR in Changsha was 124.43 billion RMB (about US $18.11 billion) in 2021. If the valuation is properly applied, it is an effective approach to attract more private sectors to participate in the CWR project; (2) The expected Willingness to Pay (WTP) for the contractor were 13.26 RMB/ton (about US$1.93/ton) for residue soil, 8.84 RMB/ton (about US $1.29/ton) for demolition and engineering waste, and 94.20 RMB/ton (about US $13.71/ton) for decoration waste. According to the result, the Construction Waste (CW) landfill behavior can be reduced by setting reasonable landfill charge through appropriate policies; (3) There were significant differences between urban residents and construction contractors in perception of CWR non-market valuation. The WTP of urban residents was influenced by sex, age, accelerated industrial development, and other factors. The WTP of construction contractors was influenced by the Health, Safety, and Environment management fee, region of project location, method of CW disposal, and other factors. The government should show a positive attitude and responsibility for CWR, so as to play an important role in leading urban residents and construction contractors. Although the study is based on the example of Changsha in China, it can also be adapted to other countries and regions as well.
摘要：
The beam-only connected reinforced concrete shear wall (BRW) is used as a reinforcing component to enhance the seismic performance of concrete-filled, double-skin steel tube (CFDST) frames. The effects of the BRW on seismic risks of CFDST frames are investigated. Three performance levels of limit states are defined and described according to the typical failure of test specimens and the existing definition of current guidance. A simplified numerical model is calibrated for CFDST frame-BRW structures, and test results validate it. Nonlinear dynamic analyses on a nine-story CFDST-BRW building are performed to investigate the effects of BRW on reducing the seismic risk of CFDST buildings. The results show that the BRW reduces the probability of collapse of the CFDST frame to 2.76% in 50 years, which can effectively reduce the probability of different degrees of damage in the service cycle of the structure. The results provide information for risk-informed decision-making on the design of CFDST frame-BRW structures.
作者机构：
[Fan, Wenchen; Jiang, Xueliang] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha 410004, Hunan, Peoples R China.;[Fan, Wenchen] Changsha Univ Sci & Technol, Engn Res Ctr Catastroph Prophylaxis & Treatment Rd, Minist Educ, Changsha 410114, Hunan, Peoples R China.;[Wang, Xingxing] Chengmenshan Copper Mine Jiangxi Copper Ind Co Ltd, Jiujiang 332114, Jiangxi, Peoples R China.;[Cao, Ping] Cent South Univ, Sch Resources & Safety Engn, Changsha 410083, Hunan, Peoples R China.
通讯机构：
[Wenchen Fan] S;School of Civil Engineering, Central South University of Forestry and Technology, Changsha, China<&wdkj&>Engineering Research Center of Catastrophic Prophylaxis and Treatment of Road and Traffic Safety of Ministry of Education, Changsha University of Science and Technology, Changsha, China
摘要：
Photon cloud data filtering is crucial when obtaining forest vertical structure parameters from photon-counting LiDAR data. The proposed method, for the first time, takes into account the influence of the density difference between canopy photons and ground photons. A moving overlapping window approach is introduced to reduce the impact of an uneven background noise environment first. In each window, a modified elevation histogram statistics vector in the elevation direction is proposed to increase the density difference between signal and noise photons while also reducing the density difference between canopy and ground photons. The filtering results show that the average overall accuracy (OA) and standard deviation of the proposed method reach almost 0.99 and 0.01, respectively, which are much better results than those of the other existing filtering methods. Specifically, with the increase in the ratio of canopy photons to ground photons, the F-measure value of the proposed method reaches almost 0.99, and is also stable, which demonstrates that the proposed approach can almost completely eliminate the influence of the density difference between canopy photons and ground photons on the filtering results. In addition, the forest canopy heights obtained based on the proposed filtering method achieve the lowest root-mean-square error (RMSE) value of 3.18 m, compared to the other filtering methods. In summary, the proposed photon cloud data filtering method can retrieve reliable forest canopy height information from photon cloud data, and outperforms the other compared filtering methods in the given test site.
摘要：
A novel near-infrared induced upconversion sensor for the detection of uranyl ions was successfully constructed using (beta-NaYF4: Yb, Tm, Gd upconversion nanoparticles (UCNPs) and specific DNAzyme. Characterization of the UCNPs@DNAzyme was conducted using XRD, TEM, FT-IR and fluorescence testing, and it was shown that the (beta-NaYF4: Yb, Tm, Gd nanoparticles were successfully prepared (similar to 27 nm). Upon 980 nm excitation, the UCNPs@DNAzyme emitted green light at lambda = 475 nm. Furthermore, Forster resonance energy transfer was observed between the UCNPs@DNAzyme (doner) and uranyl (acceptor) present on the substrate chain. This resulted in fluorescence quenching, which was used to quantify the concentration of uranyl. The developed method was found to be highly selective and sensitive, with a detection limit as low as 43 nM. This method also demonstrated excellent specificity and sensitivity for the determination of uranyl in water samples, indicating its potential application in near-infrared fluorescence detection and imaging of uranyl in vivo.
摘要：
In this study, three coupled modes of coupling effect of sulfate attack and carbonation of concrete were carried out to investigate the change of mass, mechanical properties and apparent morphology. The phase composition, microstructure and morphological char-acteristics of erosion products were also studied by using environment scanning electron microscope (ESEM-EDS), Fourier infrared spectrometer (FTIR), and X-ray diffraction (XRD). The results indicated that the coupled mode played an obvious effect on the performance and microstructures of specimen due to effects of coupled mode on the deterioration mechanism and erosion products. The surface feature of specimen became worse with carbonation time, and plenty of surface efflorescence and desquamation of products were observed under the coupled mode of carbonation followed by sulfate attack. The relative compressive strength and dynamic elastic modulus of concrete specimen first increased and then decreased with carbonation time, and there existed relationship of a cubic function of single variable between them. The relative mass of concrete specimen increased with the increase of the erosion age of sulfate attack. The difference of the carbonation time per period test played a significant effect on the relative compressive strength and dynamic elastic modulus of concrete specimen, which was due to the dominant effect of carbonation.& COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
摘要：
Uranyl coordination polymers have caught more and more attention due to their rich topological structures and potential practical applications in nuclear waste processing and management. In this work, four novel uranyl coordination polymers have been successfully synthesized by the utilization of a semirigid ligand and uranyl nitrate under hydrothermal reactions through the introducing of different kinds of auxiliary ligands (NaCl, oxalate acid, succinic acid). Therein, the powder X-ray diffraction, Infrared spectroscopy and luminescence properties of compounds 3 and 4 are investigated.
