The bending behavior of double-row stabilizing plies is associated with the constructional time delay(CTD),which can be defined as the time interval between the installations of the front stabilizing pile and the rear...The bending behavior of double-row stabilizing plies is associated with the constructional time delay(CTD),which can be defined as the time interval between the installations of the front stabilizing pile and the rear stabilizing pile.This paper investigates the effect of CTD on the bending moments of double-row stabilizing piles and a method for determining the optimal CTD is proposed.The stabilizing pile is modeled as a cantilever pile embedded in the Winkler elastic foundation.A triangular distributed earth pressure is assumed on the pile segment in the sliding layer.The front stabilizing pile and the rear stabilizing pile are connected by a beam with pinned joints.The analytical solutions of bending moments on the front and the rear stabilizing piles are derived and the accuracy of bending moment solutions is validated by comparing the tensile strain measured from the Hongyan landslide project,Taizhou,Zhejiang,China.It is concluded that CTD has a significant influence on the bending moments of double-row stabilizing piles.An optimal CTD can be obtained when the maximum tensile stress in the front stabilizing pile is equal to that in the rear stabilizing pile,which is 1.4 months for the Hongyan landslide project.展开更多
Creep tests under at a certain temperature and different stress levels were performed on two carbon constructional quality steels at a certain stress level and different temperatures,and their creep curves at high tem...Creep tests under at a certain temperature and different stress levels were performed on two carbon constructional quality steels at a certain stress level and different temperatures,and their creep curves at high temperature were obtained based on analyzing the testing data.Taking 45 steel at a certain temperature and stress as the example,the integral creep constitutive equation and the differential stress-strain constitutive relationship were established based on the relevant rheological model,and the integral core function was also obtained.Simultaneously,the viscous coefficients denoting the viscous behavior in visco-plastic constitutive equation were determined by taking use of the creep testing data.Then the viscous coefficients of three carbon steels(20 steel,35 steel and 45 steel) were compared and analyzed.The results show that the viscosity is different due to different materials at the same temperature and stress.展开更多
Constructional engineering is the fundamental industry of China and along with the constantly improving of science and technology level in recent years, BIM technology has been gradually applied in constructional engi...Constructional engineering is the fundamental industry of China and along with the constantly improving of science and technology level in recent years, BIM technology has been gradually applied in constructional engineering field of China, and it has exerted relatively sound application effects, thus actively proving the construction efficiency and quality. In this study, mainly based on BIM technology, I analyze the application of BIM technology in structural design of constructional engineering respectively from field data analysis, structure parameter design, interior design and professional coordination design, and analyze the application effects of BIM technology in structural design of constructional engineering by combining practical cases, which is expected to serve as the effective theoretical basis for the improvement of structural design of constructional engineering in China.展开更多
This paper briefly introduces the meaning of concrete pouring construction technology, and introduces the preparation work of concrete pouring construction in construction engineering. It focuses on the analysis and d...This paper briefly introduces the meaning of concrete pouring construction technology, and introduces the preparation work of concrete pouring construction in construction engineering. It focuses on the analysis and discussion of the application of concrete pouring construction technology in constructional engineering for reference.展开更多
With the continuous development of the economy, Chinese architecture is constantly improving and developing. Therefore, it is important to improve the management and control of construction costs. This paper briefly a...With the continuous development of the economy, Chinese architecture is constantly improving and developing. Therefore, it is important to improve the management and control of construction costs. This paper briefly analyzes some problems in the cost management and control of construction engineering, and puts forward some measures to strengthen the cost management and control of construction engineering, in order to improve the cost efficiency of China's construction engineering and promote the sustainable development of construction engineering.展开更多
In the Republic of Kazakhstan, the regulatory framework in construction based on Eurocodes has been in force since 2015. However, Kazakhstani produced steel has not been studied for compliance with the requirements of...In the Republic of Kazakhstan, the regulatory framework in construction based on Eurocodes has been in force since 2015. However, Kazakhstani produced steel has not been studied for compliance with the requirements of Eurocode 1993. This has resulted in limited use of Kazakhstani structural steel in construction. The feasibility of using structural steel in welded joints has been experimentally investigated. To verify the application of such joints in construction, including earthquake engineering, experimental studies of welded joints made of structural steel produced by Arcelor-Mittal in Temirtau have been carried out. In total, 7 types of structural steel of various thicknesses were selected. Five specimens have been used in each series of tests. The Brinell hardness values of the weld joint, yield strength of steel and tensile strength, relative rupture strain were determined. It was found that for all types of structural steel, the quality of weld joints complied with the requirements of Eurocode 1993—a sample rupture appeared along the plates (main body of the metal), not along the weld joints. It has been established that structural steel produced in the Republic of Kazakhstan fully complies with the requirements of Eurocode 1993. The studies on the dependence of Brinell hardness values of weld joint steel on the yield strength, tensile strength and relative rupture strain have been carried out. The correlation dependences between the values of yield strength of steel and tensile strength, relative rupture strain and BH Brinell hardness were studied. The results of work will allow for significantly increasing the use of Kazakhstani structural steel in seismic and conventional areas of the Republic of Kazakhstan.展开更多
As blockchain technology rapidly evolves,smart contracts have seen widespread adoption in financial transactions and beyond.However,the growing prevalence of malicious Ponzi scheme contracts presents serious security ...As blockchain technology rapidly evolves,smart contracts have seen widespread adoption in financial transactions and beyond.However,the growing prevalence of malicious Ponzi scheme contracts presents serious security threats to blockchain ecosystems.Although numerous detection techniques have been proposed,existing methods suffer from significant limitations,such as class imbalance and insufficient modeling of transaction-related semantic features.To address these challenges,this paper proposes an oversampling-based detection framework for Ponzi smart contracts.We enhance the Adaptive Synthetic Sampling(ADASYN)algorithm by incorporating sample proximity to decision boundaries and ensuring realistic sample distributions.This enhancement facilitates the generation of high-quality minority class samples and effectively mitigates class imbalance.In addition,we design a Contract Transaction Graph(CTG)construction algorithm to preserve key transactional semantics through feature extraction from contract code.A graph neural network(GNN)is then applied for classification.This study employs a publicly available dataset from the XBlock platform,consisting of 318 verified Ponzi contracts and 6498 benign contracts.Sourced from real Ethereum deployments,the dataset reflects diverse application scenarios and captures the varied characteristics of Ponzi schemes.Experimental results demonstrate that our approach achieves an accuracy of 96%,a recall of 92%,and an F1-score of 94%in detecting Ponzi contracts,outperforming state-of-the-art methods.展开更多
The discharge of micro-polluted water from sources such as agricultural runoff,urban stormwater,and treated effluents presents significant challenges to aquatic ecosystems.Constructed wetlands(CWs)have gained recog-ni...The discharge of micro-polluted water from sources such as agricultural runoff,urban stormwater,and treated effluents presents significant challenges to aquatic ecosystems.Constructed wetlands(CWs)have gained recog-nition as an eco-friendly solution for removing pollutants from various wastewater sources and are increasingly applied for micro-polluted water treatment.By reviewing 78 full-scale CW studies from Web of Science,it is summarized that the ranges of ammonium nitrogen(NH4+-N)concentrations in runoff,wastewater treatment plant effluent and polluted river were 0.1–6.6,0.3–12.3,and 0.2–41.1 mg/L,respectively.The ranges of ni-trate nitrogen concentrations were 0.2–14.2,0–5.7,and 0–2.6 mg/L,respectively.Removal efficiencies of CWs for micro-polluted water varied by CW types.The total nitrogen removal efficiencies for subsurface-flow CWs,free-water surface-flow CWs,and hybrid CWs ranged from 27.4%to 66.5%,16.8%to 89.8%,and 19.4%to 88.2%,respectively.The NH4+-N removal efficiencies ranged from 34.2%to 73.6%,38.4%to 89.4%and 13.5%to 94.2%,respectively.Additionally,other factors influencing contaminant removal efficiency such as hydraulic retention time,vegetation types,redox micro-environment and influent water quality were evaluated.Based on these findings,two strategies for improving the purification performance of CWs were proposed:the selection of incorporating electron donor substrates and the optimization of operation parameters.This paper serves as a synthesis of information to guide future research and full-scale CW applications in micro-polluted water treatment.展开更多
Oil-fired construction machinery(OCM)is a major source of urban air pollutants and CO_(2) emissions,and elec-trification is a crucial pathway for improving air quality and achieving China’s dual carbon goals;however,...Oil-fired construction machinery(OCM)is a major source of urban air pollutants and CO_(2) emissions,and elec-trification is a crucial pathway for improving air quality and achieving China’s dual carbon goals;however,its feasibility has not been fully explored.This study uses data envelopment analysis and the analytic hierarchy process to establish a development potential index,covering technical efficiency,economic cost,application sce-narios,and charging time and range,with an empirical analysis conducted in Beijing.The findings indicated the high feasibility of replacing OCM with electric alternatives,especially within the low-power range.Based on 2023 registered coding dat1,it is projected that by 2030,electrification could reduce regional average con-centrations of CO,NO_(x),PM_(2.5) and VOCs by 12.2%to 56.4%and reduce CO_(2) by 11.7%to 56.9%.Owing to economic considerations,small-and medium-sized machinery are particularly feasible for electrification.Key recommendations include prioritizing the electrification of forklifts,lifting platforms,and small-sized machinery in high-emission areas,particularly in central urban districts.Policies such as carbon taxes,carbon markets,and performance grading systems are suggested to incentivize electrification,along with expanding high-emission restriction zones and improving energy infrastructure to support widespread electrification.展开更多
Anammox bacteria in constructed wetlands(CWs)play pivotal role in sustainable nitrogen transformation,yet existing studies lack comprehensive analysis of environmental gradients and microbial interactions,both key fac...Anammox bacteria in constructed wetlands(CWs)play pivotal role in sustainable nitrogen transformation,yet existing studies lack comprehensive analysis of environmental gradients and microbial interactions,both key factors in anammox bacteria enrichment.This study investigated the mechanisms driving anammox bacteria enrichment in lab-scale simulated CWs treating high-nitrogen wastewater,focusing on bacterial community re-sponses across wetland layers with various strategies,including continuous up-flow influent,nitrogen loading increase,effluent recirculation,intermittent influent,and anammox bacteria inoculation.Results showed that total relative and absolute abundances of anammox bacteria ranged from 0.77%to 12.50%and from 0.13 to 6.46×10^(7) copies/g,respectively.Dissolved oxygen and pH had significant positive correlations with the absolute abundance of anammox bacteria,while organic matter and nitrate negatively impacted their relative abundance.Permutational multivariate analysis of variance indicated that spatial heterogeneity explained more variation in anammox bacteria abundance(43.44%)compared to operational strategies(8.58%).In terms of microbial interactions,60 dominant species exhibited potential correlations with anammox bacteria,comprising 170 interactions(105 positive and 65 negative),which suggested that anammox bacteria generally foster cooperative relationships with dominant bacteria.Notably,significant interspecies interactions were observed between Candidatus Kuenenia(dominant anammox bacteria in CWs)and species within the genera Chitinivibrio-nia and Anaerolineaceae,suggesting that microbial interactions primarily manifest as indirect facilitative effects rather than direct mutualistic relationships.Given that the Normalized Stochasticity Ratio in CWs were<50%,this study inferred that environmental gradients have greater influence on anammox bacteria than microbial interactions.展开更多
The transition to sustainable energy systems necessitates efficient hydrogen production via water electrolysis,with anion-exchange membrane water electrolyzers(AEMWEs)emerging as a cost-effective alternative by combin...The transition to sustainable energy systems necessitates efficient hydrogen production via water electrolysis,with anion-exchange membrane water electrolyzers(AEMWEs)emerging as a cost-effective alternative by combining the merits of alkaline water electrolyzers(AWEs)and proton-exchange membrane water electrolyzers(PEMWEs).However,challenges persist in membrane stability,oxygen evolution reaction(OER)kinetics,and mass transport efficiency.This review highlights the pivotal role of transition metal-based layered double hydroxides(LDHs)as high-performance,non-precious OER catalysts for AEMWEs,emphasizing their tunable electronic structures,abundant active sites,and alkaline stability.We systematically outline LDHs synthesis strategies(top-down/bottom-up approaches,and self-supporting LDHs engineering on the conductive substrates),and AEMWE component design,including membraneelectrode assembly optimization and ionomer-free architectures.Standardized evaluation protocols-short-circuit inspection,impedance spectroscopy,and durability assessment are detailed to benchmark performance.Moreover,recent advances in LDHs modification(cation/anion doping,heterojunction design,three-dimensional(3D)electrode structuring)are discussed for alkaline-fed systems,alongside emerging applications in seawater and pure-water electrolysis.By correlating material innovations with device-level metrics,this work provides a roadmap to address scalability challenges,offering perspectives on advancing AEMWEs for sustainable,large-scale hydrogen production.展开更多
To advance intelligent construction,standards must come first.The Ministry of Housing and Urban-Rural Development has issued the List for Replicable Experience and Practices for Developing Intelligent Construction fou...To advance intelligent construction,standards must come first.The Ministry of Housing and Urban-Rural Development has issued the List for Replicable Experience and Practices for Developing Intelligent Construction four times successively and the Technical Guidelines for Intelligent Construction(Trial).展开更多
To fully leverage the advantages of mechanization and informatization in tunnel boring machine(TBM)operations,the authors aim to promote the advancement of tunnel construction technology toward intelligent development...To fully leverage the advantages of mechanization and informatization in tunnel boring machine(TBM)operations,the authors aim to promote the advancement of tunnel construction technology toward intelligent development.This involved exploring the deep integration of next-generation artificial intelligence technologies,such as sensing technology,automatic control technology,big data technology,deep learning,and machine vision,with key operational processes,including TBM excavation,direction adjustment,step changes,inverted arch block assembly,material transportation,and operation status assurance.The results of this integration are summarized as follows.(1)TBM key excavation parameter prediction algorithm was developed with an accuracy rate exceeding 90%.The TBM intelligent step-change control algorithm,based on machine vision,achieved an image segmentation accuracy rate of 95%and gripper shoe positioning error of±5 mm.(2)An automatic positioning system for inverted arch blocks was developed,enabling real-time perception of the spatial position and deviation during the assembly process.The system maintains an elevation positioning deviation within±3 mm and a horizontal positioning deviation within±10 mm,reducing the number of surveyors in each work team.(3)A TBM intelligent rail transportation system that achieves real-time human-machine positioning,automatic switch opening and closing,automatic obstacle avoidance,intelligent transportation planning,and integrated scheduling and command was designed.Each locomotive formation reduces one shunter and improves comprehensive transportation efficiency by more than 20%.(4)Intelligent analysis and prediction algorithms were developed to monitor and predict the trends of the hydraulic and gear oil parameters in real time,enhancing the proactive maintenance and system reliability.展开更多
Construction engineering and management(CEM)has become increasingly complicated with the increasing size of engineering projects under different construction environments,motivating the digital transformation of CEM.T...Construction engineering and management(CEM)has become increasingly complicated with the increasing size of engineering projects under different construction environments,motivating the digital transformation of CEM.To contribute to a better understanding of the state of the art of smart techniques for engineering projects,this paper provides a comprehensive review of multi-criteria decision-making(MCDM)techniques,intelligent techniques,and their applications in CEM.First,a comprehensive framework detailing smart technologies for construction projects is developed.Next,the characteristics of CEM are summarized.A bibliometric review is then conducted to investigate the keywords,journals,and clusters related to the application of smart techniques in CEM during 2000-2022.Recent advancements in intelligent techniques are also discussed under the following six topics:①big data technology;②computer vision;③speech recognition;④natural language processing;⑤machine learning;and⑥knowledge representation,understanding,and reasoning.The applications of smart techniques are then illustrated via underground space exploitation.Finally,future research directions for the sustainable development of smart construction are highlighted.展开更多
Marine infrastructure is increasingly vulnerable to harsh environmental conditions that accelerate the degradation of traditional materials such as Portland cement concrete and carbon steel.This review systematically ...Marine infrastructure is increasingly vulnerable to harsh environmental conditions that accelerate the degradation of traditional materials such as Portland cement concrete and carbon steel.This review systematically investigates recent advancements in sustainable alternatives,including geopolymer concrete,engineered innovacementitious composites(ECC),bio-concrete,fiber-reinforced polymers(FRPs),and bamboo,stainless steel,and steel-CFRP hybrid bars.Each material is evaluated based on marine durability,mechanical performance,environmental impact,and cost feasibility using life cycle assessment,durability modelling,and a multi-criteria decisionsupport framework.The results reveal that geopolymer concrete and FRP reinforcement’s exhibit superior corrosion resistance and environmental benefits,while ECC and steel-CFRP composites offer structural resilience with moderate environmental trade-offs.However,challenges remain in long-term performance validation,standardization,and market integration.The review concludes that a combined approach involving innovative materials,computational tools,and sustainability assessment is essential for advancing marine infrastructure.Outlook recommendations include focused field studies,development of regulatory guidelines,and interdisciplinary collaboration to drive the practical adoption of eco-efficient materials in coastal and offshore construction.展开更多
Zeolite-loaded noble metal catalysts have demonstrated excellent performance in addressing cold-start automotive exhaust NOx emissions and catalytic oxidation of VOCs applications.Pd and Pt are the most commonly used ...Zeolite-loaded noble metal catalysts have demonstrated excellent performance in addressing cold-start automotive exhaust NOx emissions and catalytic oxidation of VOCs applications.Pd and Pt are the most commonly used active metals in PNA and VOC catalysts,respectively.However,despite the same metal/zeolite composition,the efficient active sites for PNA and VOC catalysts have been viewed as mainly Pd^(2+) and Pt^(0),respectively,both of which are different from each other.As a result,various methods need to be applied to dope Pd and Pt in zeolitic support respectively for different usages.No matter which type of metal species is needed,the common requirement for both PNA and VOC catalysts is that the metal species should be highly dispersed in zeolite support and stay stable.The purpose of this paper is to review the progress of synthetic means of zeolite-coated noble metals(Pd,Pt,etc.)as effective PNA or VOC catalysts.To give a better understanding of the relationship between efficient metal species and the introduced methods,the species that contributed to the NOx adsorption(PNA)and VOCs deep catalytic oxidation were first summarized and compared.Then,based on the above discussion,the detailed construction strategies for different active sites in PNA and VOC catalysts,respectively,were elaborated in terms of synthetic routes,precursor selection,and zeolite carrier requirements.It is hoped that this will contribute to a better understanding of noble metal adsorption/catalysis in zeolites and provide promising strategies for the design of adsorption/catalysts with high activity,selectivity and stability.展开更多
Scientific and technological advancements are rapidly transforming underground engineering,shifting from labor-intensive,time-consuming methods to automated,real-time systems.This timely and comprehensive review cover...Scientific and technological advancements are rapidly transforming underground engineering,shifting from labor-intensive,time-consuming methods to automated,real-time systems.This timely and comprehensive review covers in-situ testing,intelligent monitoring,and geophysical testing methods,highlighting fundamental principles,testing apparatuses,data processing techniques,and engineering applications.The state-of-the-art summary emphasizes not only cutting-edge innovations for complex and harsh environments but also the transformative role of artificial intelligence and machine learning in data interpretations.The integration of big data and advanced algorithms is particularly impactful,enabling the identification,prediction,and mitigation of potential risks in underground projects.Key aspects of the discussion include detection capabilities,method integration,and data convergence of intelligent technologies to drive enhanced safety,operational efficiency,and predictive reliability.The review also examines future trends in intelligent technologies,emphasizing unified platforms that combine multiple methods,real-time data,and predictive analytics.These advancements are shaping the evolution of underground construction and maintenance,aiming for risk-free,high-efficiency underground engineering.展开更多
To understand the smoke level and NO_(x)emission characteristics of in-use construction machinery in Beijing,we selected 905 construction machines in Beijing from August 2022 to April 2023 to monitor the emission leve...To understand the smoke level and NO_(x)emission characteristics of in-use construction machinery in Beijing,we selected 905 construction machines in Beijing from August 2022 to April 2023 to monitor the emission level of smoke and NO_(x).The exhaust smoke level and excessive emission situation of different machinery types were identified,and their NO_(x)emission levels were monitored according to the free acceleration method.We investigated the correlation of NO_(x)and smoke emission,and proposed suggestions for controlling pollution discharge from construction machinery in the future.The results show that the exhaust smoke level was 0–2.62 m^(−1),followed a log-normal distribution(μ=-1.73,δ=1.09,R^(2)=0.99),with a 5.64%exceedance rate.Differenceswere observed amongmachinery types,with low-power engine forklifts showing higher smoke levels.The NO_(x)emission range was 71–1516 ppm,followed a normal distribution(μ=565.54,δ=309.51,R^(2)=0.83).Differences among machinery types were relatively small.Engine rated net power had the most significant impact on NO_(x)emissions.Thus,NO_(x)emissions from construction machinery need further attention.Furthermore,we found a weak negative correlation(p<0.05)between the emission level of smoke and NO_(x),that is the synergic emission reduction effect is poor,emphasizing the need for NO_(x)emission limits.In the future,the oversight in Beijing should prioritize phasing out ChinaⅠand ChinaⅡmachinery,and monitor emissions from highpower engine ChinaⅢmachinery.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 40972187)the Key Innovation Team Support Project of Zhejiang Province (No. 2009R50050)
文摘The bending behavior of double-row stabilizing plies is associated with the constructional time delay(CTD),which can be defined as the time interval between the installations of the front stabilizing pile and the rear stabilizing pile.This paper investigates the effect of CTD on the bending moments of double-row stabilizing piles and a method for determining the optimal CTD is proposed.The stabilizing pile is modeled as a cantilever pile embedded in the Winkler elastic foundation.A triangular distributed earth pressure is assumed on the pile segment in the sliding layer.The front stabilizing pile and the rear stabilizing pile are connected by a beam with pinned joints.The analytical solutions of bending moments on the front and the rear stabilizing piles are derived and the accuracy of bending moment solutions is validated by comparing the tensile strain measured from the Hongyan landslide project,Taizhou,Zhejiang,China.It is concluded that CTD has a significant influence on the bending moments of double-row stabilizing piles.An optimal CTD can be obtained when the maximum tensile stress in the front stabilizing pile is equal to that in the rear stabilizing pile,which is 1.4 months for the Hongyan landslide project.
基金Project(07031B) supported by the Scientific Research Fund of Central South University of Forestry and Technology
文摘Creep tests under at a certain temperature and different stress levels were performed on two carbon constructional quality steels at a certain stress level and different temperatures,and their creep curves at high temperature were obtained based on analyzing the testing data.Taking 45 steel at a certain temperature and stress as the example,the integral creep constitutive equation and the differential stress-strain constitutive relationship were established based on the relevant rheological model,and the integral core function was also obtained.Simultaneously,the viscous coefficients denoting the viscous behavior in visco-plastic constitutive equation were determined by taking use of the creep testing data.Then the viscous coefficients of three carbon steels(20 steel,35 steel and 45 steel) were compared and analyzed.The results show that the viscosity is different due to different materials at the same temperature and stress.
文摘Constructional engineering is the fundamental industry of China and along with the constantly improving of science and technology level in recent years, BIM technology has been gradually applied in constructional engineering field of China, and it has exerted relatively sound application effects, thus actively proving the construction efficiency and quality. In this study, mainly based on BIM technology, I analyze the application of BIM technology in structural design of constructional engineering respectively from field data analysis, structure parameter design, interior design and professional coordination design, and analyze the application effects of BIM technology in structural design of constructional engineering by combining practical cases, which is expected to serve as the effective theoretical basis for the improvement of structural design of constructional engineering in China.
文摘This paper briefly introduces the meaning of concrete pouring construction technology, and introduces the preparation work of concrete pouring construction in construction engineering. It focuses on the analysis and discussion of the application of concrete pouring construction technology in constructional engineering for reference.
文摘With the continuous development of the economy, Chinese architecture is constantly improving and developing. Therefore, it is important to improve the management and control of construction costs. This paper briefly analyzes some problems in the cost management and control of construction engineering, and puts forward some measures to strengthen the cost management and control of construction engineering, in order to improve the cost efficiency of China's construction engineering and promote the sustainable development of construction engineering.
文摘In the Republic of Kazakhstan, the regulatory framework in construction based on Eurocodes has been in force since 2015. However, Kazakhstani produced steel has not been studied for compliance with the requirements of Eurocode 1993. This has resulted in limited use of Kazakhstani structural steel in construction. The feasibility of using structural steel in welded joints has been experimentally investigated. To verify the application of such joints in construction, including earthquake engineering, experimental studies of welded joints made of structural steel produced by Arcelor-Mittal in Temirtau have been carried out. In total, 7 types of structural steel of various thicknesses were selected. Five specimens have been used in each series of tests. The Brinell hardness values of the weld joint, yield strength of steel and tensile strength, relative rupture strain were determined. It was found that for all types of structural steel, the quality of weld joints complied with the requirements of Eurocode 1993—a sample rupture appeared along the plates (main body of the metal), not along the weld joints. It has been established that structural steel produced in the Republic of Kazakhstan fully complies with the requirements of Eurocode 1993. The studies on the dependence of Brinell hardness values of weld joint steel on the yield strength, tensile strength and relative rupture strain have been carried out. The correlation dependences between the values of yield strength of steel and tensile strength, relative rupture strain and BH Brinell hardness were studied. The results of work will allow for significantly increasing the use of Kazakhstani structural steel in seismic and conventional areas of the Republic of Kazakhstan.
基金supported by the Key Project of Joint Fund of the National Natural Science Foundation of China“Research on Key Technologies and Demonstration Applications for Trusted and Secure Data Circulation and Trading”(U24A20241)the National Natural Science Foundation of China“Research on Trusted Theories and Key Technologies of Data Security Trading Based on Blockchain”(62202118)+4 种基金the Major Scientific and Technological Special Project of Guizhou Province([2024]014)Scientific and Technological Research Projects from the Guizhou Education Department(Qian jiao ji[2023]003)the Hundred-Level Innovative Talent Project of the Guizhou Provincial Science and Technology Department(Qiankehe Platform Talent-GCC[2023]018)the Major Project of Guizhou Province“Research and Application of Key Technologies for Trusted Large Models Oriented to Public Big Data”(Qiankehe Major Project[2024]003)the Guizhou Province Computational Power Network Security Protection Science and Technology Innovation Talent Team(Qiankehe Talent CXTD[2025]029).
文摘As blockchain technology rapidly evolves,smart contracts have seen widespread adoption in financial transactions and beyond.However,the growing prevalence of malicious Ponzi scheme contracts presents serious security threats to blockchain ecosystems.Although numerous detection techniques have been proposed,existing methods suffer from significant limitations,such as class imbalance and insufficient modeling of transaction-related semantic features.To address these challenges,this paper proposes an oversampling-based detection framework for Ponzi smart contracts.We enhance the Adaptive Synthetic Sampling(ADASYN)algorithm by incorporating sample proximity to decision boundaries and ensuring realistic sample distributions.This enhancement facilitates the generation of high-quality minority class samples and effectively mitigates class imbalance.In addition,we design a Contract Transaction Graph(CTG)construction algorithm to preserve key transactional semantics through feature extraction from contract code.A graph neural network(GNN)is then applied for classification.This study employs a publicly available dataset from the XBlock platform,consisting of 318 verified Ponzi contracts and 6498 benign contracts.Sourced from real Ethereum deployments,the dataset reflects diverse application scenarios and captures the varied characteristics of Ponzi schemes.Experimental results demonstrate that our approach achieves an accuracy of 96%,a recall of 92%,and an F1-score of 94%in detecting Ponzi contracts,outperforming state-of-the-art methods.
基金supported by the Natural Science Foundation of China(No.52470105)the Young Taishan Scholars Program of Shandong Province(No.358202103017).
文摘The discharge of micro-polluted water from sources such as agricultural runoff,urban stormwater,and treated effluents presents significant challenges to aquatic ecosystems.Constructed wetlands(CWs)have gained recog-nition as an eco-friendly solution for removing pollutants from various wastewater sources and are increasingly applied for micro-polluted water treatment.By reviewing 78 full-scale CW studies from Web of Science,it is summarized that the ranges of ammonium nitrogen(NH4+-N)concentrations in runoff,wastewater treatment plant effluent and polluted river were 0.1–6.6,0.3–12.3,and 0.2–41.1 mg/L,respectively.The ranges of ni-trate nitrogen concentrations were 0.2–14.2,0–5.7,and 0–2.6 mg/L,respectively.Removal efficiencies of CWs for micro-polluted water varied by CW types.The total nitrogen removal efficiencies for subsurface-flow CWs,free-water surface-flow CWs,and hybrid CWs ranged from 27.4%to 66.5%,16.8%to 89.8%,and 19.4%to 88.2%,respectively.The NH4+-N removal efficiencies ranged from 34.2%to 73.6%,38.4%to 89.4%and 13.5%to 94.2%,respectively.Additionally,other factors influencing contaminant removal efficiency such as hydraulic retention time,vegetation types,redox micro-environment and influent water quality were evaluated.Based on these findings,two strategies for improving the purification performance of CWs were proposed:the selection of incorporating electron donor substrates and the optimization of operation parameters.This paper serves as a synthesis of information to guide future research and full-scale CW applications in micro-polluted water treatment.
基金supported by the National Science and Technology Major Project of the Ministry of Science and Technology of China(No.2024ZD1200200).
文摘Oil-fired construction machinery(OCM)is a major source of urban air pollutants and CO_(2) emissions,and elec-trification is a crucial pathway for improving air quality and achieving China’s dual carbon goals;however,its feasibility has not been fully explored.This study uses data envelopment analysis and the analytic hierarchy process to establish a development potential index,covering technical efficiency,economic cost,application sce-narios,and charging time and range,with an empirical analysis conducted in Beijing.The findings indicated the high feasibility of replacing OCM with electric alternatives,especially within the low-power range.Based on 2023 registered coding dat1,it is projected that by 2030,electrification could reduce regional average con-centrations of CO,NO_(x),PM_(2.5) and VOCs by 12.2%to 56.4%and reduce CO_(2) by 11.7%to 56.9%.Owing to economic considerations,small-and medium-sized machinery are particularly feasible for electrification.Key recommendations include prioritizing the electrification of forklifts,lifting platforms,and small-sized machinery in high-emission areas,particularly in central urban districts.Policies such as carbon taxes,carbon markets,and performance grading systems are suggested to incentivize electrification,along with expanding high-emission restriction zones and improving energy infrastructure to support widespread electrification.
基金supported by Natural Science Foundation of Xiamen,China(No.3502Z20227232)the STS Project of Fujian-CAS(No.2023T3018)Bureau of International Cooperation,Chinese Academy of Sciences(No.322GJHZ2022035MI).
文摘Anammox bacteria in constructed wetlands(CWs)play pivotal role in sustainable nitrogen transformation,yet existing studies lack comprehensive analysis of environmental gradients and microbial interactions,both key factors in anammox bacteria enrichment.This study investigated the mechanisms driving anammox bacteria enrichment in lab-scale simulated CWs treating high-nitrogen wastewater,focusing on bacterial community re-sponses across wetland layers with various strategies,including continuous up-flow influent,nitrogen loading increase,effluent recirculation,intermittent influent,and anammox bacteria inoculation.Results showed that total relative and absolute abundances of anammox bacteria ranged from 0.77%to 12.50%and from 0.13 to 6.46×10^(7) copies/g,respectively.Dissolved oxygen and pH had significant positive correlations with the absolute abundance of anammox bacteria,while organic matter and nitrate negatively impacted their relative abundance.Permutational multivariate analysis of variance indicated that spatial heterogeneity explained more variation in anammox bacteria abundance(43.44%)compared to operational strategies(8.58%).In terms of microbial interactions,60 dominant species exhibited potential correlations with anammox bacteria,comprising 170 interactions(105 positive and 65 negative),which suggested that anammox bacteria generally foster cooperative relationships with dominant bacteria.Notably,significant interspecies interactions were observed between Candidatus Kuenenia(dominant anammox bacteria in CWs)and species within the genera Chitinivibrio-nia and Anaerolineaceae,suggesting that microbial interactions primarily manifest as indirect facilitative effects rather than direct mutualistic relationships.Given that the Normalized Stochasticity Ratio in CWs were<50%,this study inferred that environmental gradients have greater influence on anammox bacteria than microbial interactions.
基金supported by the National Natural Science Foundation of China(Nos.52122308 and 22305225)the Postdoctoral Fellowship Program of CPSF(No.GZC20232391).
文摘The transition to sustainable energy systems necessitates efficient hydrogen production via water electrolysis,with anion-exchange membrane water electrolyzers(AEMWEs)emerging as a cost-effective alternative by combining the merits of alkaline water electrolyzers(AWEs)and proton-exchange membrane water electrolyzers(PEMWEs).However,challenges persist in membrane stability,oxygen evolution reaction(OER)kinetics,and mass transport efficiency.This review highlights the pivotal role of transition metal-based layered double hydroxides(LDHs)as high-performance,non-precious OER catalysts for AEMWEs,emphasizing their tunable electronic structures,abundant active sites,and alkaline stability.We systematically outline LDHs synthesis strategies(top-down/bottom-up approaches,and self-supporting LDHs engineering on the conductive substrates),and AEMWE component design,including membraneelectrode assembly optimization and ionomer-free architectures.Standardized evaluation protocols-short-circuit inspection,impedance spectroscopy,and durability assessment are detailed to benchmark performance.Moreover,recent advances in LDHs modification(cation/anion doping,heterojunction design,three-dimensional(3D)electrode structuring)are discussed for alkaline-fed systems,alongside emerging applications in seawater and pure-water electrolysis.By correlating material innovations with device-level metrics,this work provides a roadmap to address scalability challenges,offering perspectives on advancing AEMWEs for sustainable,large-scale hydrogen production.
文摘To advance intelligent construction,standards must come first.The Ministry of Housing and Urban-Rural Development has issued the List for Replicable Experience and Practices for Developing Intelligent Construction four times successively and the Technical Guidelines for Intelligent Construction(Trial).
文摘To fully leverage the advantages of mechanization and informatization in tunnel boring machine(TBM)operations,the authors aim to promote the advancement of tunnel construction technology toward intelligent development.This involved exploring the deep integration of next-generation artificial intelligence technologies,such as sensing technology,automatic control technology,big data technology,deep learning,and machine vision,with key operational processes,including TBM excavation,direction adjustment,step changes,inverted arch block assembly,material transportation,and operation status assurance.The results of this integration are summarized as follows.(1)TBM key excavation parameter prediction algorithm was developed with an accuracy rate exceeding 90%.The TBM intelligent step-change control algorithm,based on machine vision,achieved an image segmentation accuracy rate of 95%and gripper shoe positioning error of±5 mm.(2)An automatic positioning system for inverted arch blocks was developed,enabling real-time perception of the spatial position and deviation during the assembly process.The system maintains an elevation positioning deviation within±3 mm and a horizontal positioning deviation within±10 mm,reducing the number of surveyors in each work team.(3)A TBM intelligent rail transportation system that achieves real-time human-machine positioning,automatic switch opening and closing,automatic obstacle avoidance,intelligent transportation planning,and integrated scheduling and command was designed.Each locomotive formation reduces one shunter and improves comprehensive transportation efficiency by more than 20%.(4)Intelligent analysis and prediction algorithms were developed to monitor and predict the trends of the hydraulic and gear oil parameters in real time,enhancing the proactive maintenance and system reliability.
基金funded by the project of Guangdong Provincial Basic and Applied Basic Research Fund Committee(2022A1515240073)the Pearl River Talent Recruitment Program(2019CX01G338),Guangdong Province.
文摘Construction engineering and management(CEM)has become increasingly complicated with the increasing size of engineering projects under different construction environments,motivating the digital transformation of CEM.To contribute to a better understanding of the state of the art of smart techniques for engineering projects,this paper provides a comprehensive review of multi-criteria decision-making(MCDM)techniques,intelligent techniques,and their applications in CEM.First,a comprehensive framework detailing smart technologies for construction projects is developed.Next,the characteristics of CEM are summarized.A bibliometric review is then conducted to investigate the keywords,journals,and clusters related to the application of smart techniques in CEM during 2000-2022.Recent advancements in intelligent techniques are also discussed under the following six topics:①big data technology;②computer vision;③speech recognition;④natural language processing;⑤machine learning;and⑥knowledge representation,understanding,and reasoning.The applications of smart techniques are then illustrated via underground space exploitation.Finally,future research directions for the sustainable development of smart construction are highlighted.
文摘Marine infrastructure is increasingly vulnerable to harsh environmental conditions that accelerate the degradation of traditional materials such as Portland cement concrete and carbon steel.This review systematically investigates recent advancements in sustainable alternatives,including geopolymer concrete,engineered innovacementitious composites(ECC),bio-concrete,fiber-reinforced polymers(FRPs),and bamboo,stainless steel,and steel-CFRP hybrid bars.Each material is evaluated based on marine durability,mechanical performance,environmental impact,and cost feasibility using life cycle assessment,durability modelling,and a multi-criteria decisionsupport framework.The results reveal that geopolymer concrete and FRP reinforcement’s exhibit superior corrosion resistance and environmental benefits,while ECC and steel-CFRP composites offer structural resilience with moderate environmental trade-offs.However,challenges remain in long-term performance validation,standardization,and market integration.The review concludes that a combined approach involving innovative materials,computational tools,and sustainability assessment is essential for advancing marine infrastructure.Outlook recommendations include focused field studies,development of regulatory guidelines,and interdisciplinary collaboration to drive the practical adoption of eco-efficient materials in coastal and offshore construction.
基金supported by Zhongtian Iron and Steel-University of Science and Technology Beijing Youth Science and Technology Innovation Fund(No.FZTNTC2024050005)National Engineering Laboratory for Mobile Source Emission Control Technology,China(No.NELMS2020A07)The Fundamental Research Funds for the Central Universities,China(No.FRF-AT-20-12)。
文摘Zeolite-loaded noble metal catalysts have demonstrated excellent performance in addressing cold-start automotive exhaust NOx emissions and catalytic oxidation of VOCs applications.Pd and Pt are the most commonly used active metals in PNA and VOC catalysts,respectively.However,despite the same metal/zeolite composition,the efficient active sites for PNA and VOC catalysts have been viewed as mainly Pd^(2+) and Pt^(0),respectively,both of which are different from each other.As a result,various methods need to be applied to dope Pd and Pt in zeolitic support respectively for different usages.No matter which type of metal species is needed,the common requirement for both PNA and VOC catalysts is that the metal species should be highly dispersed in zeolite support and stay stable.The purpose of this paper is to review the progress of synthetic means of zeolite-coated noble metals(Pd,Pt,etc.)as effective PNA or VOC catalysts.To give a better understanding of the relationship between efficient metal species and the introduced methods,the species that contributed to the NOx adsorption(PNA)and VOCs deep catalytic oxidation were first summarized and compared.Then,based on the above discussion,the detailed construction strategies for different active sites in PNA and VOC catalysts,respectively,were elaborated in terms of synthetic routes,precursor selection,and zeolite carrier requirements.It is hoped that this will contribute to a better understanding of noble metal adsorption/catalysis in zeolites and provide promising strategies for the design of adsorption/catalysts with high activity,selectivity and stability.
基金supported by Ministry of Education of Singapore,under Academic Research Fund Tier 1(Grant Number RG143/23).
文摘Scientific and technological advancements are rapidly transforming underground engineering,shifting from labor-intensive,time-consuming methods to automated,real-time systems.This timely and comprehensive review covers in-situ testing,intelligent monitoring,and geophysical testing methods,highlighting fundamental principles,testing apparatuses,data processing techniques,and engineering applications.The state-of-the-art summary emphasizes not only cutting-edge innovations for complex and harsh environments but also the transformative role of artificial intelligence and machine learning in data interpretations.The integration of big data and advanced algorithms is particularly impactful,enabling the identification,prediction,and mitigation of potential risks in underground projects.Key aspects of the discussion include detection capabilities,method integration,and data convergence of intelligent technologies to drive enhanced safety,operational efficiency,and predictive reliability.The review also examines future trends in intelligent technologies,emphasizing unified platforms that combine multiple methods,real-time data,and predictive analytics.These advancements are shaping the evolution of underground construction and maintenance,aiming for risk-free,high-efficiency underground engineering.
基金supported by the Energy Foundation(No.G-2203-33693).
文摘To understand the smoke level and NO_(x)emission characteristics of in-use construction machinery in Beijing,we selected 905 construction machines in Beijing from August 2022 to April 2023 to monitor the emission level of smoke and NO_(x).The exhaust smoke level and excessive emission situation of different machinery types were identified,and their NO_(x)emission levels were monitored according to the free acceleration method.We investigated the correlation of NO_(x)and smoke emission,and proposed suggestions for controlling pollution discharge from construction machinery in the future.The results show that the exhaust smoke level was 0–2.62 m^(−1),followed a log-normal distribution(μ=-1.73,δ=1.09,R^(2)=0.99),with a 5.64%exceedance rate.Differenceswere observed amongmachinery types,with low-power engine forklifts showing higher smoke levels.The NO_(x)emission range was 71–1516 ppm,followed a normal distribution(μ=565.54,δ=309.51,R^(2)=0.83).Differences among machinery types were relatively small.Engine rated net power had the most significant impact on NO_(x)emissions.Thus,NO_(x)emissions from construction machinery need further attention.Furthermore,we found a weak negative correlation(p<0.05)between the emission level of smoke and NO_(x),that is the synergic emission reduction effect is poor,emphasizing the need for NO_(x)emission limits.In the future,the oversight in Beijing should prioritize phasing out ChinaⅠand ChinaⅡmachinery,and monitor emissions from highpower engine ChinaⅢmachinery.
