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Effect of lysozyme combined with hydrothermal pretreatment on excess sludge and anaerobic digestion

Journal of Environmental Sciences 2025年第1期147卷 36-49页

作者： Xiuqin Cao Songyue Li Chaolei Liu School of Environment and Energy engineering Beijing University of Civil Engineering and ArchitectureBeijing 100044China Key Laboratory of Urban Storm water System and Water Environment(Ministry of Education) Beijing University of Civil Engineering and ArchitectureBeijing 100044China

Anaerobic digestion(AD)is widely employed for sludge stabilization and waste ***,the slow hydrolysis process hinders methane production and leads to prolonged sludge *** this study,an efficient and eco-friendly lysozyme pre-treatment method was utilized to address these *** optimizing lysozyme dosage,hydrolysis and cell lysis were ***,lysozyme combined with hydrothermal pretreatment enhanced overall *** indicate that:(1)When lysozyme dosage reached 90 mg/g TS after 240 min of pretreatment,SCOD,soluble polysaccharides,and protein content reached their maxima at 855.00,44.09,and 204.86 mg/L,*** represented an increase of 85.87%,365.58%,and 259.21%compared to the untreated *** fluorescence spectroscopy revealed the highest fluorescence intensity in the IV region(soluble microbial product),promoting microbial metabolic activity.(2)Lysozyme combined with hydrothermal pretreatment significantly increased SCOD,soluble proteins,and polysaccharide release from sludge,reducing SCOD release *** experiments identified Group 3 as the most effective for SCOD and soluble polysaccharide release,while Group 9 released the most soluble *** significance order of factors influencing SCOD,soluble proteins,and polysaccharide release is hydrothermal temperature>hydrothermal time>enzymatic digestion time.(3)The lysozyme-assisted hydrothermal pretreatment group exhibited the fastest release and the highest SCOD concentration of 8,135.00 mg/L during anaerobic *** SCOD consumption and cumulative gas production increased by 95.89%and 130.58%,respectively,compared to the control group,allowing gas production to conclude 3 days earlier.

关键词： Excess sludge Lysozyme Hydrothermal pre-treatment Anaerobic digestion Gas production

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A six-variable quasi-3D isogeometric approach for free vibration of functionally graded graphene origami-enabled auxetic metamaterial plates submerged in a fluid medium

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 157-176页

作者： Wei CHEN Zhihong TANG Yufen LIAO Linxin PENG College of civil engineering University of South China College of civil engineering and architecture Guangxi University Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education Guangxi University

This paper presents, for the first time, an effective numerical approach based on the isogeometric analysis(IGA) and the six-variable quasi-three dimensional(3D)higher-order shear deformation theory(HSDT) to study the free vibration characteristics of functionally-graded(FG) graphene origami(GOri)-enabled auxetic metamaterial(GOEAM) plates submerged in a fluid medium. The plate theory incorporates the thickness stretching and the effects of transverse shear deformation without using any shear correction factors. The velocity potential function and Bernoulli's equation are used to derive the hydrodynamic pressure acting on the plate surface. Both horizontally and vertically immersed plate configurations are considered here in the form of inertia *** plates are composed of multilayer GOEAMs, with the GOri content varying through the plate's thickness in a layer-wise manner. This design results in graded auxetic *** material properties are evaluated by mixing rules and a genetic programming(GP)-assisted micromechanical model. The governing equations of motion for the FG-GOEAM plates immersed in a fluid medium are derived by Hamilton's principle. After validating the convergence and accuracy of the present model, a comprehensive parametric study is carried out to examine the effects of the GOri content, GOri distribution pattern, GOri folding degree, fluid level, immersed depth, and geometric parameter on the natural frequencies of the FG-GOEAM plates. The results show that the natural frequencies for the four GOri distribution patterns increase with the increase in the layer number when the lay number is fewer than 10, and then stabilize after the layer number reaches ***, in general, the natural frequency of the FG-GOEAM plate in a vacuum or fluid increases when the GOri content increases, while decreases when the GOri folding degree increases. Some additional findings related to the numerical results are presented in the conclusions. It is belie

关键词： free vibration functionally-graded (FG) graphene origami (GOri)-enabled auxetic metamaterial (GOEAM) plate hydrodynamic pressure isogeometric analysis (IGA) O321 quasi-three dimensional (3D) higher-order shear deformation theory (HSDT)

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Effects of spatial heterogeneity on pseudo-static stability of coal mine overburden dump slope,using random limit equilibrium and random finite element methods:A comparative study

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Earthquake engineering and engineering Vibration 2025年第1期24卷 83-99页

作者： Madhumita Mohanty Rajib Sarkar Sarat Kumar Das Department of civil engineering Indian Institute of Technology(ISM)DhanbadDhanbad 826004India

Sudden and unforeseen seismic failures of coal mine overburden(OB)dump slopes interrupt mining operations,cause loss of lives and delay the production of *** of the spatial heterogeneity of OB dump materials is imperative for an adequate evaluation of the seismic stability of OB dump *** this study,pseudo-static seismic stability analyses are carried out for an OB dump slope by considering the material parameters obtained from an insitu field *** heterogeneity is simulated through use of the random finite element method(RFEM)and the random limit equilibrium method(RLEM)and a comparative study is *** of horizontal and vertical spatial correlation lengths were considered for simulating isotropic and anisotropic random fields within the OB dump *** performances of the slope have been reported through the probability of failure and reliability *** was observed that the RLEM approach overestimates failure probability(P_(f))by considering seismic stability with spatial *** P_(f)was observed to increase with an increase in the coefficient of variation of friction angle of the dump ***,it was inferred that the RLEM approach may not be adequately applicable for assessing the seismic stability of an OB dump slope for a horizontal seismic coefficient that is more than or equal to 0.1.

关键词： coal mine overburden dump slope random limit equilibrium method random finite element method seismic slope stability spatial heterogeneity

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Aluminum foam as buffer layer used in soft rock tunnel with large deformation

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Journal of Mountain Science 2025年第1期22卷 324-336页

作者： WU Faquan MIAO Binxin TIAN Yun ZHANG Fang ZHANG Chaoxuan School of civil engineering Shaoxing UniversityShaoxing 312000China Key Laboratory of Rock Mechanics and Geohazards of Zhejiang Province Shaoxing 312000China School of civil engineering and architecture Taizhou UniversityTaizhou 318000China

The squeezing deformation of surrounding rock is an important factor restricting the safe construction and long-term operation of tunnels when a tunnel passes through soft strata with high ground *** such soft rock geological conditions,the large deformation of the surrounding rock can easily lead to the failure of supporting structures,including shotcrete cracks,spalling,and steel arch *** improve the lining support performance during the large deformation of squeezed surrounding rock,this work selects aluminum foam with densities of 0.25 g/cm3,0.42 g/cm3 and 0.61 g/cm3 as the buffer layer material and carries out uniaxial confined compression *** the evaluation and analysis of energy absorption and the comparison of the yield pressure of aluminum foam with those of other cushioning materials and yield pressure support systems,the strength,deformation and energy absorption of aluminum foam with a density of 0.25 g/cm3 meet the yield pressure performance *** numerical model of the buffer layer yielding support system is then established via the finite element analysis software ABAQUS,and the influence of the buffer layer setting on the lining support is *** with the conventional support scheme,the addition of an aluminum foam buffer layer can reduce the stress and deformation of the primary support and secondary *** maximum and minimum principal stresses of the primary support are reduced by 13%and 15%,*** maximum and minimum principal stresses of the secondary lining are reduced by 15%and 12%,respectively,and the displacement deformation of the secondary lining position is reduced by 15%.In summary,the application of aluminum foam buffer layer can reduce the stress and deformation of the primary support and secondary lining,improve the stress safety of the support and reduce the deformation of the support.

关键词： Soft rock tunnel Uniaxial confined compression Aluminum foam Buffer layer Yielding support

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The formation,development and classification of rail corrugation:a survey on Chinese metro

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Railway engineering Science 2025年第1期33卷 43-61页

作者： Yang Wang Hong Xiao Zhihai Zhang Xuhao Cui Yihao Chi Mahantesh M.Nadakatti School of civil engineering Beijing Jiaotong UniversityBeijing 100044China Beijing Key Laboratory of Track engineering Beijing Jiaotong UniversityBeijing 100044China Faculty of architecture Civil and Transportation EngineeringBeijing University of TechnologyBeijing 100124China Department of Mechanical engineering KLS Gogte Institute of TechnologyBelagavi 590008India

Investigations into rail corrugation within metro systems have traditionally focused on specific mechanisms,thereby limiting the generalizability of proposed *** the commonalities in rail corrugation across diverse metro lines remains pivotal for elucidating its underlying *** present study conducted extensive field surveys and tracking tests across 14 Chinese metro *** employing t-distributed stochastic neighbor embedding(t-SNE)for dimensional reduction and employing the unsupervised clustering algorithm DBSCAN,the research redefines the classification of metro rail corrugation based on characteristic *** analysis encompassed spatial distribution and temporal evolution of this *** revealed that floating slab tracks exhibited the highest proportion of rail corrugation at 47%.Notably,ordinary monolithic bed tracks employing damping fasteners were more prone to inducing rail *** primarily manifested in curve sections with radii between 300 and 500 m,featuring ordinary monolithic bed track and steel-spring floating slab track structures,with wavelengths typically between 30 and 120 ***–slip vibrations of the wheel–rail system maybe led to short-wavelength corrugations(40–60 mm),while longer wavelengths(200–300 mm)exhibited distinct fatigue damage characteristics,mainly observed in steel-spring floating slab tracks and small-radius curve sections of ordinary monolithic bed tracks and ladder sleeper tracks.A classification system comprising 57 correlated features categorized metro rail corrugation into four distinct *** research outcomes serve as critical benchmarks for validating various theories pertaining to rail corrugation formation.

关键词： Metro Rail corrugation Formation mechanism Development law Field test

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An SPH Framework for Earthquake-Induced Liquefaction Hazard Assessment of Geotechnical Structures

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Computer Modeling in engineering & Sciences 2025年第1期142卷 251-277页

作者： Sourabh Mhaski G.V.Ramana Department of civil engineering Indian Institute of Technology DelhiNew Delhi110016India

Earthquake-induced soil liquefaction poses significant risks to the stability of geotechnical structures *** understanding of the liquefaction triggering,and the post-failure large deformation behaviour is essential for designing resilient *** present study develops a Smoothed Particle Hydrodynamics(SPH)framework for earthquake-induced liquefaction hazard assessment of geotechnical *** coupled flowdeformation behaviour of soils subjected to cyclic loading is described using the PM4Sand model implemented in a three-phase,single-layer SPH framework.A staggered discretisation scheme based on the stress particle SPH approach is adopted to minimise numerical inaccuracies caused by zero-energy modes and tensile ***,non-reflecting boundary conditions for seismic analysis of semi-infinite soil domains using the SPH method are *** numerical framework is employed for the analysis of cyclic direct simple shear test,seismic analysis of a level ground site,and liquefaction-induced failure of the Lower San Fernando *** agreement for liquefaction triggering and post-failure behaviour demonstrates that the SPH framework can be utilised to assess the effect of seismic loading on field-scale geotechnical *** present study also serves as the basis for future advancements of the SPH method for applications related to earthquake geotechnical engineering.

关键词： Earthquake seismic liquefaction stress particle PM4Sand smoothed particle hydrodynamics(SPH)

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Effect of surface crack on the bearing capacity of strip footing placed on rock mass

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Journal of Mountain Science 2025年第1期22卷 337-353页

作者： Avneet LAHARIYA Debarghya CHAKRABORTY Department of civil engineering Indian Institute of Technology KharagpurWest Bengal 721302India

In hilly regions,the existence of surface cracks in rock mass induces a potential threat to structural ***,the present research aims to explore the impact of surface cracks on the loadbearing capacity of strip footing placed on the rock *** taking into account the various boundary constraints across the surface of crack edges,the study investigates the presence of two categories of surface cracks,namely(1)separated crack,and(2)fine *** lower bound limit analysis is employed in conjunction with the finite element method(LBFELA)to conduct the numerical *** order to evaluate rock mass yielding,the power conic programming(PCP)method is utilized to implement the generalized Hoek-Brown(GHB)failure *** stability of the strip footing is analyzed by determining the bearing capacity factor(Nσγ),which is presented in the form of design charts by varying the strength parameters of rock,including the Geological Strength Index(GSI),Hoek-Brown material parameter(mi),Disturbance factor(D),and Normalised Uniaxial Compressive Strength(σci/γB),whereγis the unit weight of rock mass,and B is the width of strip *** study also investigates the impact of cracks on strip footings,considering different positions of the crack(LC)and depths of the crack(DC).The results demonstrate that the influence of the fine crack is only noticeable until the LC/B ratio reaches ***,for the separated crack,its impact remains significant even when the LC/B ratio exceeds *** appearance of fine crack at the edge of the footing results in a decrease in the magnitude Nσγof up to 45%,indicating a substantial reduction in the stability of the *** failure patterns are presented and discussed in detail for various cases in this study to examine the effect of surface cracks on the strip footing and to address the extent of the plastic collapse.

关键词： Rock mass Surface cracks Strip footing Power cone programming GHB failure criterion Limit analysis

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Influence of a non-free field subsurface seismic history on the liquefaction resistance of sandy soils

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Earthquake engineering and engineering Vibration 2025年第1期24卷 53-68页

作者： Liu Liteng Wang Xiaolei Liu Run Liu Libo Cao Zhipeng Zhang Fan College of civil engineering Hebei University of EngineeringHandan 056038China institute of Geotechnical engineering Tianjin UniversityTianjin 300072China

Seismic-induced liquefaction of sandy soils can fail foundations in the vicinity of *** investigate the effect of a non-free field subsurface seismic history on the ability of saturated sandy soils to resist liquefaction,four shaking events with different accelerations were input to the sandy soils in the *** results of the study revealed that:(1)Shallow soils that are not free-field undergo acceleration amplification effects after being subjected to seismic loading.(2)Building overburden pressure reduces the sensitivity of the shallow soils directly below in small and moderate earthquakes,which are more prone to rearranging and forming unstable structures under strong seismic *** excess pore pressure response on the load side resembles that of a free site,with the depth range of the liquefaction strength of soils affected by the seismic history,increasing progressively as input seismic intensity increases.(3)After experiencing earthquakes of different intensities,the excess pore pressure directly below the building overburden pressure at 0.1 m and 0.2 m is greater than that at the *** the same time,the side of the building structure is more prone to liquefaction than the soil directly below it.

关键词： non-free site seismic history liquefaction resistance excess pore pressure shaking table test

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RF Optimizer Model for Predicting Compressive Strength of Recycled Concrete

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 215-223页

作者： LIU Lin WANG Liuyan WANG Hui SUN Huayue School of civil engineering and architecture Shenyang UniversityShenyang 110000China

Traditional machine learning(ML)encounters the challenge of parameter adjustment when predicting the compressive strength of reclaimed *** address this issue,we introduce two optimized hybrid models:the Bayesian optimization model(B-RF)and the optimal model(Stacking model).These models are applied to a data set comprising 438 observations with five input variables,with the aim of predicting the compressive strength of reclaimed ***,we evaluate the performance of the optimized models in comparison to traditional machine learning models,such as support vector regression(SVR),decision tree(DT),and random forest(RF).The results reveal that the Stacking model exhibits superior predictive performance,with evaluation indices including R2=0.825,MAE=2.818 and MSE=14.265,surpassing the traditional ***,we also performed a characteristic importance analysis on the input variables,and we concluded that cement had the greatest influence on the compressive strength of reclaimed concrete,followed by ***,the Stacking model can be recommended as a compressive strength prediction tool to partially replace laboratory compressive strength testing,resulting in time and cost savings.

关键词： machine learning recycled concrete compressive strength

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Analysis of Nuclear Structure Properties and Stellar β-decay Rates of Even–Even 106–120Zr Isotopes

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Research in Astronomy and Astrophysics 2025年第1期25卷 162-174页

作者： Abdul Kabir Jameel-Un Nabi Syeda Anmol Rida Izzah Anwaar Noor-Ul Ain Raza Hamad Almujibah Department of Space Science Institute of Space Technology University of Wah Department of civil engineering College of EngineeringTaif University

The nuclear ground state properties of even–even106–120Zr nuclei have been investigated within the framework of the relativistic mean field （RMF） *** RMF model with density-dependent DDME2 and DDPC1interactions is utilized for the calculation of potential energy curves,the nuclear ground-state deformation parameters （β2）,neutron separation energies (S_nand S2n) and neutron skin thickness (rnp) of selected Zr ***,the β-decay properties of Zr isotopes were studied using the proton-neutron quasi-particle random phase approximation （pn-QRPA） *** include Gamow–Teller strength distributions,β-decay half-lives and stellar electron emission/positron capture *** β2values computed from the RMF model were employed in the pn-QRPA model as an input parameter for the calculations of β-decay properties for even–even106–120Zr *** stellar rates were computed using the pn-QRPA framework with three different types of deformation *** at high temperature （T9≥2） and low density (ρYe≤10～7g cm-3) values,the sum of electron emission and positron capture rates has a sizeable contribution （with positive exponents） to the stellar rates.

关键词： (stars:) supernovae: individual (r-process) abundances astroparticle physics elementary particles nuclear reactions nucleosynthesis

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