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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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Experimental study on failure precursory characteristics and moisture content effect of pre-cracked rocks under graded cyclic loading and unloading

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International Journal of Mining Science and Technology 2025年第2期35卷 249-264页

作者： Wei Zhang Dongxiao Zhang Weiyao Guo Baoliang Zhang school of architecture and engineering Liaocheng UniversityLiaocheng 252000China College of Energy and Mining engineering Shandong University of Science and TechnologyQingdao 266590China

It is important to analyze the damage evolution process of surrounding rock under different water content for the stability of engineering rock *** on digital speckle correlation(DSCM),acoustic emission(AE)and electromagnetic radiation(EMR),uniaxial hierarchical cyclic loading and unloading tests were carried out on sandstones with different fracture numbers under dry,natural and saturated water content,to explore the fracture propagation,failure precursor characteristics and damage response mechanism under the influence of water content *** results show that with the increase of water content,the peak stress and crack initiation stress decrease gradually,and the decreases are 15.28%-21.11%and 17.64%-23.04%,*** peak strain and crack initiation strain increase gradually,and the increases are 19.85%-44.53%and 19.15%-41.94%,*** precracked rock with different water content is mainly characterized by tensile failure at different loading ***,with the increase of water content,the proportion of shear cracks gradually increases,while acoustic emission events gradually decrease,the dissipative energy and energy storage limits of the rock under peak load gradually decrease,and the charge signal increases significantly,which is because the lubrication effect of water reduces the friction coefficient between crack surfaces.

关键词： Damage mechanisms Pre-cracked rocks Crack propagation Water-rock interaction Graded cyclic loading and unloading

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Strategies for efficient enrichment of anaerobic ammonia oxidizing bacteria in activated sludge

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Journal of Environmental Sciences 2025年第5期151卷 703-713页

作者： Bin Tang Jin Wang Xingdong Gao Zhihua Li Key Laboratory of Northwest Water Resource Environmentand EcologyMOESchool of Environmental and Municipal EngineeringXi’an University of Architecture and TechnologyXi’an 710055China Xi’an Key Laboratory of Intelligent Equipment Technology for Environmental engineering Xi’an University of Architecture and TechnologyXi’an 710055China

Anaerobic ammonia oxidation(Anammox)is an economical and sustainablewastewater nitrogen removal technology,and its application in the mainstream process is the inevitable trend of the development of ***,how to effectively enriching Anammox bacteria from the activated sludge remains challenging and restricts its extensive *** this study,the rapid and efficient enrichment of Anammox bacteriawas achieved by raising the reflux ratio and nitrogen loading rate(NLR)using conventional activated sludge as the *** the screening phase(days 1–90),the reflux ratio was increased to discharge partial floc sludge,resulting in the relative abundance of Candidatus Brocadiaceae increased from0.04%to 22.54%,which effectively reduced thematrix and spatial competition between other microorganisms and Anammox *** day 90,the stoichiometric ratio of the Anammox process closely approached the theoretical value of 1:1.32:0.26,indicating that the Anammox reaction was the primary nitrogen removal process in the *** the enrichment phase(days 91–238),the NLR increased from 0.43 to 1.20 kgN/(m^(3)·d)and removal efficiency was 71.89%,resulting in the relative abundance of Candidatus Brocadiaceae increased to 61.27%on day *** reactor operated steadily from days 444 to 498,maintaining the nitrogen removal rate(NRR)of 3.00 kgN/(m^(3)·d)and achieving successful sludge granulation with the particle size of 392.4μ*** short,this study provided a simple and efficient approach for enriching Anammox bacteria from the activated sludge,supporting to start an Anammox process efficiently.

关键词： Anammox Activated sludge Enrichment Nitrogen removal Strategy

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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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An efficient and accurate numerical method for simulating close-range blast loads of cylindrical charges based on neural network

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Defence Technology(防务技术) 2025年第2期44卷 257-271页

作者： Ting Liu Changhai Chen Han Li Yaowen Yu Yuansheng Cheng school of Naval architecture and Ocean engineering Huazhong University of Science and TechnologyWuhan 430074China Hubei Key Laboratory of Naval architecture and Ocean engineering Hydrodynamics Wuhan 430074China Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration Shanghai 200240China

To address the problems of low accuracy by the CONWEP model and poor efficiency by the Coupled Eulerian-Lagrangian(CEL)method in predicting close-range air blast loads of cylindrical charges,a neural network-based simulation(NNS)method with higher accuracy and better efficiency was *** NNS method consisted of three main ***,the parameters of blast loads,including the peak pressures and impulses of cylindrical charges with different aspect ratios(L/D)at different stand-off distances and incident angles were obtained by two-dimensional numerical ***,incident shape factors of cylindrical charges with arbitrary aspect ratios were predicted by a neural ***,reflected shape factors were derived and implemented into the subroutine of the ABAQUS code to modify the CONWEP model,including modifications of impulse and *** reliability of the proposed NNS method was verified by related experimental *** accuracy improvement was acquired by the proposed NNS method compared with the unmodified CONWEP ***,huge efficiency superiority was obtained by the proposed NNS method compared with the CEL *** proposed NNS method showed good accuracy when the scaled distance was greater than 0.2 m/kg^(1/3).It should be noted that there is no need to generate a new dataset again since the blast loads satisfy the similarity law,and the proposed NNS method can be directly used to simulate the blast loads generated by different cylindrical *** proposed NNS method with high efficiency and accuracy can be used as an effective method to analyze the dynamic response of structures under blast loads,and it has significant application prospects in designing protective structures.

关键词： Close-range air blast load Cylindrical charge Numerical method Neural network CEL method CONWEP model

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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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Interannual succession of phytoplankton community in a canyon-shaped drinking water reservoir during the initial impoundment period:Taxonomic versus functional groups

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Journal of Environmental Sciences 2025年第5期151卷 454-468页

作者： Yi Hou Ya Cheng Kai Li Meng Yang Kangzhe Huang Gang Ji Ruikang Xue Tinglin Huang Gang Wen Shaanxi Provincial Field Scientific Observation and Research Station of Water Quality in Qinling Mountains Xi’an University of Architecture and TechnologyXi’an 710055China Key Laboratory of Northwest Water Resource Environment and EcologyMOEXi’an University of Architecture and TechnologyXi’an 710055China school of Environmental and Municipal engineering Xi’an University of Architecture and TechnologyXi’an 710055China

During the initial impoundment period of a canyon-shaped reservoir,the water body fluctuated violently regarding water level,hydrological condition,and thermal *** variations may alter the structure of phytoplankton community,resulting in algal blooms and seriously threatening the ecological security of the *** is of great significance to understand the continuous changes of phytoplankton in the initial impoundment period for the protection of reservoir water ***,a two-year in-situ monitoring study was conducted on water quality and phytoplankton in a representative canyonshaped reservoir named Sanhekou and the interannual changes of phytoplankton community and its response to environmental changes during the initial impoundment period were discussed at taxonomic versus functional classification *** results showed that the total nitrogen and permanganate index levels were relatively high in the first year due to rapid water storage and heavy rainfall input,and the more stable hydrological conditions in the second year promoted the increase of algae density and the transformation of community,and the proportion of cyanobacteria increased *** succession order of phytoplankton in the first year of the initial impoundment periodwas Chlorophyta-Bacillariophyta-Chlorophyta,or J/F/X1-P/MP/W1-A/X1/MP,*** the succession order in the second year was Cyanobacteria/Chlorophyta-Bacillariophyta-Chlorophyta,or L_(M)/G/P-P/A/X1-X1/J/*** temperature,relativewater column stability,mixing depth,and pHwere crucial factors affecting phytoplankton community *** study revealed the interannual succession law and driving factors of phytoplankton in the initial impoundment period and provided an important reference for the operation management and ecological protection of canyon-shaped reservoirs.

关键词： Canyon-shaped reservoir Functional groups Initial impoundment Interannual succession Water quality

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Study on static characteristics of a novel prestress-reinforced railway subgrade

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Railway engineering Science 2025年第1期33卷 108-126页

作者： Junli Dong Fang Xu Qishu Zhang Wuming Leng Yafeng Li Qi Yang school of Civil engineering Central South UniversityChangsha 410075China MOE Key Laboratory of engineering Structures of Heavy Haul Railway Central South UniversityChangsha 410075China school of Civil engineering Central South University of Forestry and TechnologyChangsha 410004China school of Civil engineering and architecture Anhui University of Science and TechnologyHuainan 232001China

Understanding the reinforcement effect of the newly developed prestressed reinforcement components(PRCs)(a system composed of prestressed steel bars(PSBs),protective sleeves,lateral pressure plates(LPPs),and anchoring elements)is technically significant for the rational design of prestressed subgrade.A three-dimensional finite element model was established and verified based on a novel static model test and utilized to systematically analyze the influence of prestress levels and reinforcement modes on the reinforcement effect of the *** results show that the PRCs provide additional confining pressure to the subgrade through the diffusion effect of the prestress,which can therefore effectively improve the service performance of the *** to the unreinforced conventional subgrades,the settlements of prestressreinforced subgrades are *** settlement attenuation rate(Rs)near the LPPs is larger than that at the subgrade center,and increasing the prestress positively contributes to the stability of the subgrade *** the multi-row reinforcement mode,the reinforcement effect of PRCs can extend from the reinforced area to the unreinforced *** addition,as the horizontal distance from the LPPs increases,the additional confining pressure converted by the PSBs and LPPs gradually diminishes when spreading to the core load bearing area of the subgrade,resulting in a decrease in the *** the singlerow reinforcement mode,PRCs can be strategically arranged according to the local areas where subgrade defects readily occurred or observed,to obtain the desired reinforcement ***,excessive prestress should not be applied near the subgrade shoulder line to avoid the shear failure of the subgrade *** can be flexibly used for preventing and treating various subgrade defects of newly constructed or existing railway lines,achieving targeted and classified prevention,and effectively improving the bearing performance and deformati

关键词： Prestressed subgrade Static characteristic Reinforcement effect Reinforcement mode Settlement Numerical simulation

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Experimental investigation on the anti-detonation performance of composite structure containing foam geopolymer backfill material

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Defence Technology(防务技术) 2025年第1期43卷 304-318页

作者： Hang Zhou Hujun Li Zhen Wang Dongming Yan Wenxin Wang Guokai Zhang Zirui Cheng Song Sun Mingyang Wang school of Mechanical engineering Nanjing University of Science and TechnologyNanjing 210094China College of Civil engineering and architecture Zhejiang UniversityHangzhou 310058China Institute for Composites Science Innovation School of Materials Science and EngineeringZhejiang UniversityHangzhou310027China school of Safety Science and engineering(school of Emergency Management) Nanjing University of Science and TechnologyNanjing 210094China State Key Laboratory of Disaster Prevention and Mitigation of Explosion and Impact Army Engineering University of PLANanjing 210014China

The compression and energy absorption properties of foam geopolymers increase stress wave attenuation under explosion impacts,reducing the vibration effect on the *** tests were conducted using several composite structure models,including a concrete lining structure(CLS)without foam geopolymer and six foam geopolymer composite structures(FGCS)with different backfill parameters,to study the dynamic response and wave dissipation mechanisms of FGCS under explosive ***,strain,and vibration responses at different locations were synchronously *** damage modes and dynamic responses of different models were compared,and how wave elimination and energy absorption efficiencies were affected by foam geopolymer backfill parameters was *** results showed that the foam geopolymer absorbed and dissipated the impact energy through continuous compressive deformation under high strain rates and dynamic loading,reducing the strain in the liner structure by 52%and increasing the pressure attenuation rate by 28%.Additionally,the foam geopolymer backfill reduced structural vibration and liner deformation,with the FGCS structure showing 35%less displacement and 70%less acceleration compared to the *** FGCS model with thicker,less dense foam geopolymer backfill,having more pores and higher porosity,demonstrated better compression and energy absorption under dynamic impact,increasing stress wave attenuation *** analyzing the stress wave propagation and the compression characteristics of the porous medium,it was concluded that the stress transfer ratio of FGCS-ρ-579 was 77%lower than that of CLS,and the transmitted wave energy was 90%*** results of this study provide a scientific basis for optimizing underground composite structure interlayer parameters.

关键词： Explosion load Composite structure Geopolymer foam Energy absorption

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The optimal control theory——a scientific approach to fundamentally solving control problems

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Science China(Information Sciences) 2025年第1期68卷 389-391页

作者： Huanshui ZHANG school of Electrical and Automation engineering Shandong University of Science and Technology school of Control Science and engineering Shandong University

The maximum principle has bridged mathematical optimization to optimal control,ushering in significant developments and refinements in optimal control theory,notably during the 1960s with the advent of linear quadratic (LQ)control and linear quadratic estimation (LQE).This progression propelled optimal control theory into further advancements,encompassing stochastic control,robust/H-infinity control,model predictive control (MPC),networked control,and reinforcement learning *** control,established upon a rigorous mathematical foundation,extends static optimization theory to dynamic systems,exhibiting scientific essence,unity,and ***,since its inception,optimal control theory has served as an indispensable core role across all control-related domains,including communication-constrained control in networked systems,consensus control,cooperative control,and reinforcement learning control.

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