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Effects of combined antibiotics on nitrification, bacteria and antibiotic resistance genes in activated sludge: Insights from legacy effect of antibiotics

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Journal of Environmental Sciences 2023年第9期131卷 96-110页

作者： Zhong-Xing Zhang Xiao-Yan Fan Xing Li Yu-Xi Gao Jun-Ru Zhao Faculty of architecture Civil and Transportation EngineeringBeijing University of TechnologyBeijing 100124China

The effect of combined antibiotics exposure on nitrogen removal,microbial community assembly and proliferation of antibiotics resistance genes(ARGs)is a hotspot in activated sludge ***,it is unclear that how the historical antibiotic stress affects the subsequent responses of microbes and ARGs to combined *** this study,the effects of combined sulfamethoxazole(SMX)and trimethoprim(TMP)pollution on activated sludge under legacy of SMX or TMP stress with different doses(0.005-30 mg/L)were investigated to clarify antibiotic legacy *** activity was inhibited under higher level of combined exposure but a high total nitrogen removal(∼70%)*** on the full-scale classification,the legacy effect of past antibiotic stress had a marked effect on community composition of conditionally abundant taxa(CAT)and conditionally rare or abundant taxa(CRAT).Rare taxa(RT)were the keystone taxa in the microbial network,and the responses of hub genera were also affected by the legacy of antibiotic *** bacteria and genes were inhibited by the antibiotics and aerobic denitrifying bacteria(Pseudomonas,Thaurea and Hydrogenophaga)were enriched under legacy of high dose,as were the key denitrifying genes(napA,nirK and norB).Furthermore,the occurrences and co-selection relationship of 94 ARGs were affected by legacy ***,some shared hosts(eg.,Citrobacter)and hub ARGs(eg.,mdtD,mdtE and acrD)were ***,antibiotic legacy could affect responses of activated sludge to combined antibiotic and the legacy effect was stronger at higher exposure levels.

关键词： Antibiotics Antibiotic resistance genes(ARGs) Combined pollution Full-scale classification Legacy effect

In-depth understanding of transport behavior of sulfided nano zerovalent iron/reduced graphene oxide@guar gum slurry: Stability and mobility

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Journal of Environmental Sciences 2024年第10期144卷 1-14页

作者： Yuheng Ma Wenhui You Zijiang Yang Zhongyu Ren Qi Jing Faculty of architecture Civil and Transportation EngineeringBeijing University of TechnologyBeijing 100124China

Nanoscale zero-valent iron(NZVI),which has the advantages of small particle size,large specific surface area,and high reactivity,is often injected into contaminated aquifers in the form of ***,the prone to passivation and agglomeration as well as poor stability andmobility of NZVI limit the further application of this technology in ***,sulfided NZVI loaded on reduced graphene oxide(S-NZVI/rGO)and guar gum(GG)with shearthinning properties as stabilizers were used to synthesize S-NZVI/rGO@GG ***,TEM,and FT-IR confirmed that the dispersion and anti-passivation of NZVI were optimized in the coupled *** stability and mobility of the slurry were improved by increasing the GG concentration,enhancing the pH,and decreasing the ionic strength and the presence of Ca^(2+)ions,respectively.A modified advection-dispersion equation(ADE)was used to simulate the transport experiments considering the strain and physicochemical deposition/***,colloidal filtration theory(CFT)demonstrated that Brownian motion plays a dominant role in themigration of S-NZVI/rGO@GG slurry,and the maximummigration distance can be increased by appropriately increasing the injection ***-Derjaguin-Landau-Verwey-Overbeek(XDLVO)theory showed that the excellent stability and migration of S-NZVI/rGO@GG slurry mainly came from the GG spatial *** study has important implications for the field injection of S-NZVI/rGO@GG *** to the injection parameters,the injection range of S-NZVI/rGO@GG slurry is effectively controlled,which lays the foundation for the promotion of application in actual fields.

关键词： S-NZVI rGO Guar gum Transport Stability

Effects of CFB Ash on the Adsorption Mechanism of Polycarboxylate Superplasticiser

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Journal of Wuhan university of Technology(Materials Science) 2018年第6期33卷 1323-1333页

作者： LIU Juanhong GAO Meng SONG Shaomin School of civil and Resource engineering University of Science and Technology Beijing beijing Key Laboratory of Urban Underground Space engineering College of civil engineering and architecture Henan University of Technology School of civil and Transportation engineering Beijing University of Civil Engineering and Architecture

The effects of circulating fluid bed(CFB) ash on the adsorption performance of polycarboxylate superplasticiser and the mechanism of this influence on the dispersive property of the polycarboxylate superplasticiser were investigated by determing the cement paste fluidity, total organic carbon adsorption, infrared spectroscopic analyses and ζ potential test. The experimental results show that the addition of an inorganic salt into the mixture to change the content of SO42-and Fe2O3can improve the adaptability between the CFB ash and polycarboxylate superplasticiser. Adsorption may occur between the polycarboxylate superplasiciser and Fe2O3, SO42-or other components in CFB ash, leading to a significant reduction in paste fluidity. As the content of Na2SO4in CFB ash reaches 3% or Fe2O3reaches 9%, the paste loses its liquidity. The organic carbon content in the liquor decreases with an increase in Na2SO4or Fe2O3content. Adding some Ba(NO3)2and Na2S to the liquor can recover the organic carbon content to a certain extent, and the absolute value of ζ potential will increase. The addition of Ba(-NO3)2or Na2S reduces the adsorption property of Na2SO4or Fe2O3in CFB ash on the polycarboxylate superplasticiser.

关键词： CFB ash polycarboxylate superplasticiser fluidity TOC adsorption

Decontamination of Cr(Ⅵ) from water using sewage sludge-derived biochar: Role of environmentally persistent free radicals

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Chinese Journal of Chemical engineering 2023年第4期56卷 97-103页

作者： Yuhan Zhu Jia Wei Jun Li Faculty of architecture Civil and Transportation EngineeringBeijing University of TechnologyBeijing 100124China

Biochar is a well-known material for pollutant removal owing to its low cost and rich surface functionality. A kind of highly active substance, called environmentally persistent free radicals(EPFRs), can be produced in the preparation process of biochar, playing an important role in the removal of *** this study, sludge-derived biochars(SBC_(120) and SBC_(270)) were prepared by the hydrothermal carbonization under two temperatures(120℃ and 270℃) to investigate their removal abilities of Cr(Ⅵ). The maximum removal amounts of Cr(Ⅵ) by SBC_(120) and SBC_(270) were 16.58 and 22.93 mg·g^(-1), respectively. It was further revealed that the appearance of Cr(Ⅲ), as a result of EPFRs on sludge-derived biochar(SBC) transferred electrons to Cr(Ⅵ) in neutral solutions. That is to say, oxygen-centered(O-centered) EPFRs on SBC_(120) and carbon-centered(C-centered) EPFRs on SBC_(270) all could be used as electron donors to Cr(Ⅵ) to make it become Cr(Ⅲ). This study not only provides a theoretical basis for the mechanism of pollutants removal by sludge-derived biochar but also offers a new perspective on the direct effect of EPFRs on pollutants.

关键词： Sludge-derived biochar Environmentally persistent free radicals Chromium Removal Reduction

J/ψ pair hadroproduction at next-to-leading order in nonrelativistic-QCD at CMS

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Chinese Physics C 2023年第9期47卷 69-72页

作者：孙立平 School of Science Beijing University of Civil Engineering and ArchitectureBeijing 102616China

We perform a complete study of J/ψ pair hadroproduction at next-to-leading order (NLO) in the nonrelativstic-QCD (NRQCD) framework with the cc¯ pair either in the ^(3)S_(1)^([1]) or ^(1)S_(0)^([8]) fock states. It is found that the ^(1)S_(0)^([8]) channel contribution at NLO is essential. Our results indicate that for the CMS, the NRQCD predictions cannot describe the experimental data at all, and the total cross section predicted via NRQCD is smaller than the experimental data by an order of magnitude. Therefore, new mechanisms are needed to understand the CMS data for J/ψ pair production.

关键词： NRQCD next-to-leading order CMS fock state

MHD Flow and Heat Transfer of a Generalized Burgers' Fluid Due to an Exponential Accelerating Plate with Effects of the Second Order Slip and Viscous Dissipation

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Communications in Theoretical Physics 2017年第6期67卷 697-703页

作者：张艳赵豪杰白羽 School of Science Beijing University of Civil Engineering and Architecture beijing Key Laboratory of Functional Materials for Building Structure and Environment Remediation Beijing University of Civil Engineering and Architecture

In classical study on generalized viscoelastic fluid, the momentum equation was derived by considering the fractional constitutive model, while the energy equation was ignored its effect. This paper presents an investigation for the magnetohydrodynamic(MHD) flow and heat transfer of an incompressible generalized Burgers' fluid due to an exponential accelerating plate with the effect of the second order velocity slip. The energy equation and momentum equation are coupled by the fractional Burgers' fluid constitutive model. Numerical solutions for velocity, temperature and shear stress are obtained using the modified implicit finite difference method combined with the G1-algorithm,whose validity is confirmed by the comparison with the analytical solution. Our results show that the influences of the fractional parameters α and β on the flow are opposite each other, which is just like the effects of the two parameters on the temperature. Moreover, the impact trends of the relaxation time λ_1 and retardation time λ_3 on the velocity are opposite each other. Increasing the boundary parameter will promote the temperature, but has little effect on the temperature boundary layer thickness.

关键词： magnetohydrodynamic flow generalized Burgers’ fluid the second order velocity slip Riemann–Liouville fractional derivative

Test and numerical investigations on static and dynamic characteristics of extra-wide concrete self-anchored suspension bridge under vehicle loads

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Journal of Central South university 2017年第10期24卷 2382-2395页

作者： ZHOU Guang-pan LI Ai-qun LI Jian-hui DUAN Mao-jun School of civil engineering Southeast University beijing Advanced Innovation Centre for Future Urban Design Beijing University of Civil Engineering and Architecture School of civil engineering Nanjing Forestry University

The present work is aimed at studying the mechanic properties of the extra-wide concrete self-anchored suspension bridge under static and dynamic vehicle loads. Based on the field test using 12 heavy trucks and finite element simulations, the static deformations of different components, stress increments and distributions of the girder, as well as the vibration characteristics and damping ratio of the Hunan Road Bridge were analyzed, which is the widest self-anchored suspension bridge in China at present. The dynamic responses were calculated using the Newmark-β integration method assisted by the simulation models of bridge and vehicles, the influences on the dynamic impact coefficient(DIC) brought by the vehicle parameters, girder width, eccentricity travel and deck flatness were also researched. The spatial effect of the girder is obvious due to the extra width, which performs as the stress increments distribute unevenly along the transverse direction, and the girder deflections and stress increments of the upper plate change as a "V" and "M" shape respectively under the symmetrical vehicle loads affected by the shear lag effect, cross slope and local effect of the wheels, the maximum of stress increments are located in the junctions with the inner webs. The obvious girder torsional deformation and the apparent unevenness of the hanger forces between the two cable planes under the eccentric vehicle loads, together with the mode shapes such as the girder transverse bending and torsion which appear relatively earlier, all reflect the weakened torsional rigidity of the extra-wide girder. The transverse displacements of towers are more obvious than the longitudinal ones. As for the influences on the DIC, the static effect of the heavier vehicles plays a major role when pass through with a higher speed and the changes of vehicle suspension stiffness generate greater impacts than the suspension damp. The values of DIC in the vehicle-running side during the eccentric tra

关键词： self-anchored suspension bridge extra-wide girder field test simulation vehicle loads increments distribution damping ratio mode shape dynamic impact coefficient

MHD Flow and Heat Transfer of a Generalized Burgers' Fluid due to a Periodic Oscillating and Periodic Heating Plate

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Communications in Theoretical Physics 2017年第10期67卷 518-524页

作者：白羽姜月华张艳赵豪杰 School of Science Beijing University of Civil Engineering and Architecture beijing Key Laboratory of Functional Materials for Building Structure and Environment Remediation Beijing University of Civil Engineering and Architecture

This paper investigates the MHD flow and heat transfer of the incompressible generalized Burgers＇ fluid due to a periodic oscillating plate with the effects of the second order slip and periodic heating plate. The momentum equation is formulated with multi-term fractional derivatives, and by means of viscous dissipation, the fractional derivative is considered in the energy equation. A finite difference scheme is established based on the Gl-algorithm, whose convergence is confirmed by the comparison with the analytical solution in an example. Meanwhile the numerical solutions of velocity, temperature and shear stress are obtained. The effects of involved parameters on velocity and temperature fields are presented graphically and analyzed in detail. Increasing the fractional derivative parameter a, the velocity and temperature have a decreasing trend, while the influences of fractional derivative parameter ,8 on the velocity and temperature behave conversely. Increasing the absolute value of the first order slip parameter and the second order slip parameter both cause a decrease of velocity. Furthermore, with the decreasing of the magnetic parameter, the shear stress decreases.

关键词： MHD flow generalized Burgers' fluid periodic oscillating and heating fractional finite differencescheme

Optimization of Regulation Valve Location for Heating System

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湖南大学学报（自然科学版） 2009年第S1期36卷 88-90页

作者： LIU Ling-ling,CHEN Hong-bing,LI De-ying(School of Environment and Energy engineering,beijing university of civil engineering and architecture,beijing 100044,China) School of Environment and Energy engineering Beijing University of Civil Engineering and Architecture Beijing 100044 China

This paper mainly studied how to determine the best location of the self-operated flow control valve at the heating system *** the location of regulating valve directly affects the pipe network performance,the simulation and analysis of pressure change in heating system was carried out with Computational Fluid Dynamics(CFD)*** study shows the best location of regulating valve varies with the change of the supply and return pipe length when the heating area of each user is small,and when the heating area of each user is large(2 000 000～3 000 000 m2),the best location is on the supply pipe.

关键词： regulating valve optimization CFD simulation