The quantitative determination and evaluation of rock brittleness are crucial for the estimation of excavation efficiency and the improvement of hydraulic fracturing efficiency.Therefore,a“three-stage”triaxial loadi...The quantitative determination and evaluation of rock brittleness are crucial for the estimation of excavation efficiency and the improvement of hydraulic fracturing efficiency.Therefore,a“three-stage”triaxial loading and unloading stress path is designed and proposed.Subsequently,six brittleness indices are selected.In addition,the evolution characteristics of the six brittleness indices selected are characterized based on the bedding effect and the effect of confining pressure.Then,the entropy weight method(EWM)is introduced to assign weight to the six brittleness indices,and the comprehensive brittleness index Bcis defined and evaluated.Next,the new brittleness classification standard is determined,and the brittleness differences between the two stress paths are quantified.Finally,compared with the previous evaluation methods,the rationality of the proposed comprehensive brittleness index Bcis also verified.These results indicate that the proposed brittleness index Bccan reflect the brittle characteristics of deep bedded sandstone from the perspective of the whole life-cycle evolution process.Accordingly,the method proposed seems to offer reliable evaluations of the brittleness of deep bedded sandstone in deep engineering practices,although further validation is necessary.展开更多
Reinforcement corrosion is the main cause of performance deterioration of reinforced concrete(RC)structures.Limited research has been performed to investigate the life-cycle cost(LCC)of coastal bridge piers with nonun...Reinforcement corrosion is the main cause of performance deterioration of reinforced concrete(RC)structures.Limited research has been performed to investigate the life-cycle cost(LCC)of coastal bridge piers with nonuniform corrosion using different materials.In this study,a reliability-based design optimization(RBDO)procedure is improved for the design of coastal bridge piers using six groups of commonly used materials,i.e.,normal performance concrete(NPC)with black steel(BS)rebar,high strength steel(HSS)rebar,epoxy coated(EC)rebar,and stainless steel(SS)rebar(named NPC-BS,NPC-HSS,NPC-EC,and NPC-SS,respectively),NPC with BS with silane soakage on the pier surface(named NPC-Silane),and high-performance concrete(HPC)with BS rebar(named HPC-BS).First,the RBDO procedure is improved for the design optimization of coastal bridge piers,and a bridge is selected to illustrate the procedure.Then,reliability analysis of the pier designed with each group of materials is carried out to obtain the time-dependent reliability in terms of the ultimate and serviceability performances.Next,the repair time of the pier is predicted based on the time-dependent reliability indices.Finally,the time-dependent LCCs for the pier are obtained for the selection of the optimal design.展开更多
During the coronavirus disease 2019 (COVID-19) emergency, many hospitals were built or renovated around the world to meet the challenges posed by the rising number of infected cases. Environmental management in the ho...During the coronavirus disease 2019 (COVID-19) emergency, many hospitals were built or renovated around the world to meet the challenges posed by the rising number of infected cases. Environmental management in the hospital life cycle is vital in preventing nosocomial infection and includes many infection control procedures. In certain urgent situations, a hospital must be completed quickly, and work process approval and supervision must therefore be accelerated. Thus, many works cannot be checked in detail. This results in a lack of work liability control and increases the difficulty of ensuring the fulfillment of key infection prevention measures. This study investigates how blockchain technology can transform the work quality inspection workflow to assist in nosocomial infection control under a fast delivery requirement. A blockchain-based life-cycle environmental management framework is proposed to track the fulfillment of crucial infection control measures in the design, construction, and operation stages of hospitals. The proposed framework allows for work quality checking after the work is completed, when some work cannot be checked on time. Illustrative use cases are selected to demonstrate the capabilities of the developed solution. This study provides new insights into applying blockchain technology to address the challenge of environmental management brought by rapid delivery requirements.展开更多
Engineering structures may be exposed to one or more extreme hazards during their life-cycles.Current structural design specifications usually treat multiple hazards separately in designing structures and there is a l...Engineering structures may be exposed to one or more extreme hazards during their life-cycles.Current structural design specifications usually treat multiple hazards separately in designing structures and there is a limited probabilistic basis on extreme load combinations.Additionally,the performance of engineering structures will be deteriorated by the aggressive environments during their service periods,such as chloride attack,concrete carbonation,and wind-induced fatigue.This study presents a probabilistic methodology to assess the time-dependent failure probability of RC bridges with chloride-induced corrosion under the multiple hazards of earthquakes and strong winds.The loss of cross-section area of reinforcements and the reduction in strength of reinforcing steel and concrete cover induced by the chloride attack are considered.Moreover,the Poisson model is employed to obtain the occurrence probabilities of the individual and concurrent earthquake and strong wind events.The convolution integral is used to determine the joint probability distribution of combined load effects under simultaneous earthquakes and strong winds.Numerical results indicate that the structural failure probability under multiple hazards increases significantly during the bridge′s life-cycle due to the chloride corrosion effect.The contribution of each hazard event on the total structural failure probability varies with time.Thus,neglecting the combined influences of multiple hazards and chloride-induced corrosion may bring erroneous predictions in failure probability estimates of RC bridges.展开更多
As the construction sector is a major energy consumer and thus a significant contributor of CO_2 emissions in China,it is important to consider carbon reduction in this industry.This study analyzed six life-cycle stag...As the construction sector is a major energy consumer and thus a significant contributor of CO_2 emissions in China,it is important to consider carbon reduction in this industry.This study analyzed six life-cycle stages and calculated the life-cycle CO_2 emissions of the construction sector in 30 Chinese provincial jurisdictions to understand the disparity among them.Results show that building materials production was the key stage for carbon reduction in the construction sector,followed by the building operation stage.External variables,e.g.,economic growth,industrial structure,urbanization,price fluctuation,and marketization,were significantly correlated with the emission intensity of the construction sector.Specifically,economic growth exhibited an inverted U-shaped relation with CO_2 emissions per capita and per area during the period examined.Secondary industry and land urbanization were negatively correlated with CO_2 emission intensity indicators from the construction sector,whereas tertiary industry and urbanization were positively correlated.Price indices and marketization had negative effects on CO_2 emission intensity.The policy implications of our findings are that cleaner technologies should be encouraged for cement providers,and green purchasing rules for the construction sector should also be established.Pricing tools(e.g.,resource taxes)could help to adjust the demand for raw materials and energy.展开更多
With the continuous development of urban public transportation, the harmful GHG emissions and pollutants generated by itself and the consequent issues such as the losses of residents’ health, economic value and resid...With the continuous development of urban public transportation, the harmful GHG emissions and pollutants generated by itself and the consequent issues such as the losses of residents’ health, economic value and residents’ welfare have become the focus of social attention. In order to study the impacts of promoting new energy vehicles on public transportation pollution mitigation and residents’ health benefits, this paper adopts the LEAP model to build some scenarios that fulfill different development needs to quantitatively analyze the ownership of new energy buses, the reduction of pollutants and the losses of residents’ health welfare. It is concluded that promoting new energy buses comprehensively can significantly reduce the emissions of atmospheric pollutants and the economic losses of residents’ health, but cannot fully realize the targets of greenhouse gas reduction under Life Cycle Analysis.展开更多
The hydrogen fuel cell vehicle is rapidly developing in China for carbon reduction and neutrality.This paper evaluated the life-cycle cost and carbon emission of hydrogen energy via lots of field surveys,including hyd...The hydrogen fuel cell vehicle is rapidly developing in China for carbon reduction and neutrality.This paper evaluated the life-cycle cost and carbon emission of hydrogen energy via lots of field surveys,including hydrogen production and packing in chlor-alkali plants,transport by tube trailers,storage and refueling in hydrogen refueling stations(HRSs),and application for use in two different cities.It also conducted a comparative study for battery electric vehicles(BEVs)and internal combustion engine vehicles(ICEVs).The result indicates that hydrogen fuel cell vehicle(FCV)has the best environmental performance but the highest energy cost.However,a sufficient hydrogen supply can significantly reduce the carbon intensity and FCV energy cost of the current system.The carbon emission for FCV application has the potential to decrease by 73.1%in City A and 43.8%in City B.It only takes 11.0%–20.1%of the BEV emission and 8.2%–9.8%of the ICEV emission.The cost of FCV driving can be reduced by 39.1%in City A.Further improvement can be obtained with an economical and“greener”hydrogen production pathway.展开更多
The life-cycle assessment method,which originates from general products and services,has gradually come to be applied to investigations of the life-cycle carbon emissions(LCCE)of buildings.A literature review was cond...The life-cycle assessment method,which originates from general products and services,has gradually come to be applied to investigations of the life-cycle carbon emissions(LCCE)of buildings.A literature review was conducted to clarify LCCE implications,calculations,and reductions in the context of buildings.A total of 826 global building carbon emission calculation cases were obtained from 161 studies based on the framework of the building life-cycle stage division stipulated by ISO 21930 and the basic principles of the emission factor(EF)approach.The carbon emission calculation methods and results are discussed herein,based on the modules of production,construction,use,end-of-life,and supplementary benefits.According to the hotspot distribution of a building’s carbon emissions,carbon reduction strategies are classified into six groups for technical content and benefits analysis,including reducing the activity data pertaining to building materials and energy,reducing the carbon EFs of the building materials and energy,and exploiting the advantages of supplementary benefits.The research gaps and challenges in current building LCCE studies are summarized in terms of research goals and ideas,calculation methods,basic parameters,and carbon reduction strategies;development suggestions are also proposed.展开更多
There have been many studies on life cycle assessment in sewage treatment,but there are scarce few studies on the treatment of industrial wastewater in combination with advanced oxidation technology,especially in cata...There have been many studies on life cycle assessment in sewage treatment,but there are scarce few studies on the treatment of industrial wastewater in combination with advanced oxidation technology,especially in catalytic wet air oxidation(CWAO).There are no cases of using actual industrialized data onto life cycle assessment.This paper uses Simapro 9.0 software to establish a life cycle assessment model for the treatment of high-concentration organic wastewater by CWAO,and comprehensively explains the impact on the environment from three aspects:the construction phase,the operation phase and the demolition phase.In addition,sensitivity analysis and uncertainty analysis were performed.The results showed that the key factors affecting the environment were marine ecotoxicity,mineral resource consumption and global warming,the operation stage had the greatest impact on the environment,which was related to high power consumption during operation and emissions from the treatment process.Sensitivity analysis showed that electricity consumption has the greatest impact on abiotic depletion and freshwater aquatic ecotoxicity,and it also proved that global warming is mainly caused by pollutant emissions during operation phase.Monte Carlo simulations found slightly higher uncertainty for abiotic depletion and toxicity-related impact categories.展开更多
The lifecycle greenhouse gas(GHG)emissions(Well-to-Wake)from maritime transport must be reduced by at least 50%in absolute values by 2050 to contribute to the ambitions of the Paris Agreement(2015).A transition from c...The lifecycle greenhouse gas(GHG)emissions(Well-to-Wake)from maritime transport must be reduced by at least 50%in absolute values by 2050 to contribute to the ambitions of the Paris Agreement(2015).A transition from conventional fuels to alternative fuels with zero or lower GHG emissions is viewed as the most promising avenue to reach the GHG reductions.Whereas GHG and toxic pollutants emitted from the use of fossil fuels(heavy fuel oil(HFO)and marine gas/diesel oil(MGO/MDO))are generally well understood,the emissions associated with the new fuel options are only now being measured and communicated.This review provides an outlook on fuels that could help shipping respond to the decarbonization effort including Liquefied Petroleum Gas(LPG),Liquefied Natural Gas(LNG),methanol,ammonia,and hydrogen.A quantification of the pollutants associated from the use of these fuels is provided and challenges and barriers to their uptake are discussed.展开更多
This research undertook a case study of the life-cycle assessment and techno-economic analysis of the slow pyrolysis of Eucommia stem for the production of wood vinegar and activated carbon.The results showed that the...This research undertook a case study of the life-cycle assessment and techno-economic analysis of the slow pyrolysis of Eucommia stem for the production of wood vinegar and activated carbon.The results showed that the production of one ton of wood vinegar via the slow pyrolysis of Eucommia stem show comparatively low global warming potential(2.37×10^(2) kg CO_(2) eq),primary energy demand(3.16×10^(3) MJ),acidification potential(2.19 kg SO2 eq),antimony depletion potential(3.86×10^(–4) kg antimony eq),and ozone depletion potential(7.46×10^(–6) kg CFC-11 eq)and was more environmentally friendly than the production of dilute acetic acid(12 wt%)via petrochemical routes.Meanwhile,the total capital investment,total product cost,and cash flowsheet were provided in the techno-economic analysis.Then,the net present value,internal rate of return,and dynamic payback period of the production process were evaluated.The findings indicated that while this production process is cost-effective,it might not be economically attractive or could generate investment risks.An increase in the added value of the wood vinegar and the activated carbon could remarkably improve the economic feasibility of this production process.展开更多
Cybersecurity increasingly relies on machine learning(ML)models to respond to and detect attacks.However,the rapidly changing data environment makes model life-cycle management after deployment essential.Real-time det...Cybersecurity increasingly relies on machine learning(ML)models to respond to and detect attacks.However,the rapidly changing data environment makes model life-cycle management after deployment essential.Real-time detection of drift signals from various threats is fundamental for effectively managing deployed models.However,detecting drift in unsupervised environments can be challenging.This study introduces a novel approach leveraging Shapley additive explanations(SHAP),a widely recognized explainability technique in ML,to address drift detection in unsupervised settings.The proposed method incorporates a range of plots and statistical techniques to enhance drift detection reliability and introduces a drift suspicion metric that considers the explanatory aspects absent in the current approaches.To validate the effectiveness of the proposed approach in a real-world scenario,we applied it to an environment designed to detect domain generation algorithms(DGAs).The dataset was obtained from various types of DGAs provided by NetLab.Based on this dataset composition,we sought to validate the proposed SHAP-based approach through drift scenarios that occur when a previously deployed model detects new data types in an environment that detects real-world DGAs.The results revealed that more than 90%of the drift data exceeded the threshold,demonstrating the high reliability of the approach to detect drift in an unsupervised environment.The proposed method distinguishes itself fromexisting approaches by employing explainable artificial intelligence(XAI)-based detection,which is not limited by model or system environment constraints.In conclusion,this paper proposes a novel approach to detect drift in unsupervised ML settings for cybersecurity.The proposed method employs SHAP-based XAI and a drift suspicion metric to improve drift detection reliability.It is versatile and suitable for various realtime data analysis contexts beyond DGA detection environments.This study significantly contributes to theMLcommunity by addressing the critical issue of managing ML models in real-world cybersecurity settings.Our approach is distinguishable from existing techniques by employing XAI-based detection,which is not limited by model or system environment constraints.As a result,our method can be applied in critical domains that require adaptation to continuous changes,such as cybersecurity.Through extensive validation across diverse settings beyond DGA detection environments,the proposed method will emerge as a versatile drift detection technique suitable for a wide range of real-time data analysis contexts.It is also anticipated to emerge as a new approach to protect essential systems and infrastructures from attacks.展开更多
Carbon dioxide(CO_(2))emissions from the road sector have attracted increasing attention in current years.This paper attempted to provide a systematic review of the existing research efforts on road life-cycle CO_(2)e...Carbon dioxide(CO_(2))emissions from the road sector have attracted increasing attention in current years.This paper attempted to provide a systematic review of the existing research efforts on road life-cycle CO_(2)emissions by analyzing the system’s boundary division,identifying the CO_(2)emission contributions of each life-cycle phase,listing major emission contributors,exploring related emission reduction technologies,and giving directions for future development.The research showed that the road life cycle is usually divided into five phases:material production,construction,use,maintenance and end-of-life(EOL)phases.The use phase and the initial construction stage(including material production and construction phases)contributed the most CO_(2)emissions during the road life cycle.In detail,the production of cement,asphalt and steel were the three main emission contributors in the material production phase.The pavement roughness,albedo,and concrete carbonation were the main factors affecting emissions in the use phase.In addition,emission reduction technologies such as using recycled materials and recycling techniques,lowering mixing temperature,and equipment energy substitution were commonly used to reduce emissions from material production and construction phases.The application of emerging technologies such as carbon capture and storage,carbon sink,and the use of hydrogen,solar and photovoltaic in the road sector may have emission reduction potentials and should be highlighted more in future studies.展开更多
This study develops a bottom-up model to quantitatively assess the comprehensive effects of replacing traditional petroleum-powered vehicles with natural gas vehicles(NGVs) in China based on an investigation of the ...This study develops a bottom-up model to quantitatively assess the comprehensive effects of replacing traditional petroleum-powered vehicles with natural gas vehicles(NGVs) in China based on an investigation of the direct energy consumption and critical air pollutant(CAP) emission intensity, life-cycle energy use and greenhouse gas(GHG) emission intensity of NGV fleets. The results indicate that, on average, there are no net energy savings from replacing a traditional fuel vehicle with an NGV. Interestingly, an NGV results in significant reductions in direct CAP and life-cycle GHG emissions compared to those of a traditional fuel vehicle, ranging from 61% to 76% and 12% to 29%, respectively. Due to the increasing use of natural gas as a vehicle fuel in China(i.e. approximately 28.2 billion cubic metres of natural gas in2015), the total petroleum substituted with natural gas was approximately 23.8 million tonnes(Mt), which generated a GHG emission reduction of 16.9 Mt of CO2 equivalent and a CAP emission reduction of 1.8 Mt in 2015. Given the significant contribution of NGVs, growing the NGV population in 2020 will further increase the petroleum substitution benefits and CAP and GHG emission reduction benefits by approximately 42.5 Mt of petroleum-based fuel, 3.1 Mt of CAPs and 28.0 Mt of GHGs. By 2030, these benefits will reach 81.5 Mt of traditional petroleum fuel, 5.6 Mt of CAPs and 50.5 Mt of GHGs, respectively.展开更多
Unconventional oil and gas resources have become the most important and realistic field for increasing China’s domestic oil and gas reserves and production.At present,the production scale does not match the massive a...Unconventional oil and gas resources have become the most important and realistic field for increasing China’s domestic oil and gas reserves and production.At present,the production scale does not match the massive amount of resources and the rapid growth of proven geological reserves.The challenges of technology,cost,management,and methodology restrict large-scale and economic development.Based on successful practices,a"one engine with six gears"system engineering methodology is put forward,which includes life-cycle management,overall synergy,interdisciplinary cross-service integration,marketoriented operation,socialized support,digitalized management,and low-carbon and green development.The methodology has been proved to be effective in multiple unconventional oil and gas national demonstration areas,including the Jimusar continental shale oil demonstration area.Disruptive views are introduced-namely,that unconventional oil and gas do not necessarily yield a low return,nor do they necessarily have a low recovery factor.A determination to achieve economic benefit must be a pervasive underlying goal for managers and experts.Return and recovery factors,as primary focuses,must be adhered to during China’s development of unconventional oil and gas.The required methodology transformation includes a revolution in management systems to significantly decrease cost and increase production,resulting in technological innovation.展开更多
The production of polyvinyl chloride by calcium carbide method is a typical chemical process with high coal consumption,leading to massive flue gas and carbide slag emissions.Currently,the carbide slag with high CaO c...The production of polyvinyl chloride by calcium carbide method is a typical chemical process with high coal consumption,leading to massive flue gas and carbide slag emissions.Currently,the carbide slag with high CaO content is usually stacked in residue field,easily draining away with the rain and corroding the soil.In this work,we coupled the treatment of flue gas and carbide slag to propose a facile CO_(2)mineralization route to prepare light calcium carbonate.And the route feasibility was comprehensively evaluated via experiments and simulation.Through experimental investigation,the Ca^(2+) leaching and mineralization reaction parameters were determined.Based on the experiment,a process was built and optimized through Aspen Plus,and the energy was integrated to obtain the overall process energy and material consumption.Finally,the net CO_(2)emission reduction rate of the entire process through the life-cycle assessment method was analyzed.Moreover,the relationship between the parameters and the CO_(2)emission life-cycle assessment was established.The final optimization results showed that the mineralization process required 1154.69 kW·h·(t CO_(2))^(-1) of energy(including heat energy of 979.32 kW·h·(t CO_(2))^(-1) and electrical energy of 175.37 kW·h·(t CO_(2))^(-1)),and the net CO_(2)emission reduction rate was 35.8%.The light CaCO_(3)product can be sold as a high value-added product.According to preliminary economic analysis,the profit of mineralizing can reach more than 2,100 CNY·(t CO_(2))^(-1).展开更多
Product family(PF) is the most important part of product platform. A new method is proposed to mine PF based on multi-space product data in PLM database. Product structure tree(PST) and bill of material(BOM) are used ...Product family(PF) is the most important part of product platform. A new method is proposed to mine PF based on multi-space product data in PLM database. Product structure tree(PST) and bill of material(BOM) are used as the data source. A PF can be obtained by mining physics space, logic space and attribute space of product data. In this work, firstly, a PLM database is described, consisting of data organization form, data structure, and data characteristics. Then the PF mining method introduces the sequence alignment techniques used in bio-informatics, which mainly includes data pre-processing, regularization, mining algorithm and cluster analysis. Finally, the feasibility and effectiveness of the proposed method are verified by a case study of high and middle pressure valve, demonstrating a feasible method to obtain PF from PLM database.展开更多
Trypanosoma rangeli and T.cruzi are both parasitic unicellular species that infect humans.Unlike T.cruzi,the causative agent of Chagas disease,T.rangeli is an infective and non-pathogenic parasite for humans,but patho...Trypanosoma rangeli and T.cruzi are both parasitic unicellular species that infect humans.Unlike T.cruzi,the causative agent of Chagas disease,T.rangeli is an infective and non-pathogenic parasite for humans,but pathogenic for vectors from the Rhodnius genus.Because both species can coexist in different hosts and overlap their infective cycles but very little is known about the infection of T.rangeli in mammalian cells,we decided to characterize both the development of this parasite in cell culture and the effect of therapeutic agents with potential trypanocidal action on it.We found that T.rangeli exhibits a cycle of infection in Vero cells similar to that for T.cruzi and that the repurposed drug,17-AAG,and the natural extract Artemisia sp.essential oil produce a toxic effect on epimastigotes showing a trypanocidal action from the fifth day of culture.Both treatments also affected the infection of trypomastigotes and reduced the capacity of replication of amastigotes of T.rangeli.Since T.cruzi/T.rangeli coinfection cases have been reported,the finding of drugs with potential activity against both species could be significant in the future.Furthermore,studies of susceptibility of both species to drugs could also help to know the different mechanisms of pathogenicity in humans displayed by T.cruzi that are absent in T.rangeli.展开更多
Since its launch in 2011, the Materials Genome Initiative(MGI) has drawn the attention of researchers from academia,government, and industry worldwide. As one of the three tools of the MGI, the use of materials data...Since its launch in 2011, the Materials Genome Initiative(MGI) has drawn the attention of researchers from academia,government, and industry worldwide. As one of the three tools of the MGI, the use of materials data, for the first time, has emerged as an extremely significant approach in materials discovery. Data science has been applied in different disciplines as an interdisciplinary field to extract knowledge from data. The concept of materials data science has been utilized to demonstrate its application in materials science. To explore its potential as an active research branch in the big data era, a three-tier system has been put forward to define the infrastructure for the classification, curation and knowledge extraction of materials data.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52034009 and 51974319)the Yue Qi Distinguished Scholar Project(No.2020JCB01)。
文摘The quantitative determination and evaluation of rock brittleness are crucial for the estimation of excavation efficiency and the improvement of hydraulic fracturing efficiency.Therefore,a“three-stage”triaxial loading and unloading stress path is designed and proposed.Subsequently,six brittleness indices are selected.In addition,the evolution characteristics of the six brittleness indices selected are characterized based on the bedding effect and the effect of confining pressure.Then,the entropy weight method(EWM)is introduced to assign weight to the six brittleness indices,and the comprehensive brittleness index Bcis defined and evaluated.Next,the new brittleness classification standard is determined,and the brittleness differences between the two stress paths are quantified.Finally,compared with the previous evaluation methods,the rationality of the proposed comprehensive brittleness index Bcis also verified.These results indicate that the proposed brittleness index Bccan reflect the brittle characteristics of deep bedded sandstone from the perspective of the whole life-cycle evolution process.Accordingly,the method proposed seems to offer reliable evaluations of the brittleness of deep bedded sandstone in deep engineering practices,although further validation is necessary.
基金National Natural Science Foundation of China under Grant Nos.51921006 and 51725801Fundamental Research Funds for the Central Universities under Grant No.FRFCU5710093320Heilongjiang Touyan Innovation Team Program。
文摘Reinforcement corrosion is the main cause of performance deterioration of reinforced concrete(RC)structures.Limited research has been performed to investigate the life-cycle cost(LCC)of coastal bridge piers with nonuniform corrosion using different materials.In this study,a reliability-based design optimization(RBDO)procedure is improved for the design of coastal bridge piers using six groups of commonly used materials,i.e.,normal performance concrete(NPC)with black steel(BS)rebar,high strength steel(HSS)rebar,epoxy coated(EC)rebar,and stainless steel(SS)rebar(named NPC-BS,NPC-HSS,NPC-EC,and NPC-SS,respectively),NPC with BS with silane soakage on the pier surface(named NPC-Silane),and high-performance concrete(HPC)with BS rebar(named HPC-BS).First,the RBDO procedure is improved for the design optimization of coastal bridge piers,and a bridge is selected to illustrate the procedure.Then,reliability analysis of the pier designed with each group of materials is carried out to obtain the time-dependent reliability in terms of the ultimate and serviceability performances.Next,the repair time of the pier is predicted based on the time-dependent reliability indices.Finally,the time-dependent LCCs for the pier are obtained for the selection of the optimal design.
基金supported by the National Natural Science Foundation of China(71732001,51878311,72271106,U21A20151,and 71821001)Engineering Fronts Project(2021-HYZD-5-13)+1 种基金Major Science&Technology Project of Hubei(2020ACA006)China Scholarship Council(202006160115).
文摘During the coronavirus disease 2019 (COVID-19) emergency, many hospitals were built or renovated around the world to meet the challenges posed by the rising number of infected cases. Environmental management in the hospital life cycle is vital in preventing nosocomial infection and includes many infection control procedures. In certain urgent situations, a hospital must be completed quickly, and work process approval and supervision must therefore be accelerated. Thus, many works cannot be checked in detail. This results in a lack of work liability control and increases the difficulty of ensuring the fulfillment of key infection prevention measures. This study investigates how blockchain technology can transform the work quality inspection workflow to assist in nosocomial infection control under a fast delivery requirement. A blockchain-based life-cycle environmental management framework is proposed to track the fulfillment of crucial infection control measures in the design, construction, and operation stages of hospitals. The proposed framework allows for work quality checking after the work is completed, when some work cannot be checked on time. Illustrative use cases are selected to demonstrate the capabilities of the developed solution. This study provides new insights into applying blockchain technology to address the challenge of environmental management brought by rapid delivery requirements.
基金Supported by:Fundamental Research Funds for the Central Universities under Grant No.2021QN1022。
文摘Engineering structures may be exposed to one or more extreme hazards during their life-cycles.Current structural design specifications usually treat multiple hazards separately in designing structures and there is a limited probabilistic basis on extreme load combinations.Additionally,the performance of engineering structures will be deteriorated by the aggressive environments during their service periods,such as chloride attack,concrete carbonation,and wind-induced fatigue.This study presents a probabilistic methodology to assess the time-dependent failure probability of RC bridges with chloride-induced corrosion under the multiple hazards of earthquakes and strong winds.The loss of cross-section area of reinforcements and the reduction in strength of reinforcing steel and concrete cover induced by the chloride attack are considered.Moreover,the Poisson model is employed to obtain the occurrence probabilities of the individual and concurrent earthquake and strong wind events.The convolution integral is used to determine the joint probability distribution of combined load effects under simultaneous earthquakes and strong winds.Numerical results indicate that the structural failure probability under multiple hazards increases significantly during the bridge′s life-cycle due to the chloride corrosion effect.The contribution of each hazard event on the total structural failure probability varies with time.Thus,neglecting the combined influences of multiple hazards and chloride-induced corrosion may bring erroneous predictions in failure probability estimates of RC bridges.
基金Under the auspices of the National Natural Science Foundation of China(No.41101567)
文摘As the construction sector is a major energy consumer and thus a significant contributor of CO_2 emissions in China,it is important to consider carbon reduction in this industry.This study analyzed six life-cycle stages and calculated the life-cycle CO_2 emissions of the construction sector in 30 Chinese provincial jurisdictions to understand the disparity among them.Results show that building materials production was the key stage for carbon reduction in the construction sector,followed by the building operation stage.External variables,e.g.,economic growth,industrial structure,urbanization,price fluctuation,and marketization,were significantly correlated with the emission intensity of the construction sector.Specifically,economic growth exhibited an inverted U-shaped relation with CO_2 emissions per capita and per area during the period examined.Secondary industry and land urbanization were negatively correlated with CO_2 emission intensity indicators from the construction sector,whereas tertiary industry and urbanization were positively correlated.Price indices and marketization had negative effects on CO_2 emission intensity.The policy implications of our findings are that cleaner technologies should be encouraged for cement providers,and green purchasing rules for the construction sector should also be established.Pricing tools(e.g.,resource taxes)could help to adjust the demand for raw materials and energy.
文摘With the continuous development of urban public transportation, the harmful GHG emissions and pollutants generated by itself and the consequent issues such as the losses of residents’ health, economic value and residents’ welfare have become the focus of social attention. In order to study the impacts of promoting new energy vehicles on public transportation pollution mitigation and residents’ health benefits, this paper adopts the LEAP model to build some scenarios that fulfill different development needs to quantitatively analyze the ownership of new energy buses, the reduction of pollutants and the losses of residents’ health welfare. It is concluded that promoting new energy buses comprehensively can significantly reduce the emissions of atmospheric pollutants and the economic losses of residents’ health, but cannot fully realize the targets of greenhouse gas reduction under Life Cycle Analysis.
基金supported by the Consulting Research Project of the Chinese Academy of Engineering(Grant No.2019-XZ-51).
文摘The hydrogen fuel cell vehicle is rapidly developing in China for carbon reduction and neutrality.This paper evaluated the life-cycle cost and carbon emission of hydrogen energy via lots of field surveys,including hydrogen production and packing in chlor-alkali plants,transport by tube trailers,storage and refueling in hydrogen refueling stations(HRSs),and application for use in two different cities.It also conducted a comparative study for battery electric vehicles(BEVs)and internal combustion engine vehicles(ICEVs).The result indicates that hydrogen fuel cell vehicle(FCV)has the best environmental performance but the highest energy cost.However,a sufficient hydrogen supply can significantly reduce the carbon intensity and FCV energy cost of the current system.The carbon emission for FCV application has the potential to decrease by 73.1%in City A and 43.8%in City B.It only takes 11.0%–20.1%of the BEV emission and 8.2%–9.8%of the ICEV emission.The cost of FCV driving can be reduced by 39.1%in City A.Further improvement can be obtained with an economical and“greener”hydrogen production pathway.
基金supported by the National Natural Science Foundation of China(51825802,52130803,52278020,and 72374121)the China National Key Research and Development Program(2018YFE0106100)+1 种基金the China Postdoctoral Science Foundation(2022M711815)the New Cornerstone Science Foundation through the XPLORER PRIZE.
文摘The life-cycle assessment method,which originates from general products and services,has gradually come to be applied to investigations of the life-cycle carbon emissions(LCCE)of buildings.A literature review was conducted to clarify LCCE implications,calculations,and reductions in the context of buildings.A total of 826 global building carbon emission calculation cases were obtained from 161 studies based on the framework of the building life-cycle stage division stipulated by ISO 21930 and the basic principles of the emission factor(EF)approach.The carbon emission calculation methods and results are discussed herein,based on the modules of production,construction,use,end-of-life,and supplementary benefits.According to the hotspot distribution of a building’s carbon emissions,carbon reduction strategies are classified into six groups for technical content and benefits analysis,including reducing the activity data pertaining to building materials and energy,reducing the carbon EFs of the building materials and energy,and exploiting the advantages of supplementary benefits.The research gaps and challenges in current building LCCE studies are summarized in terms of research goals and ideas,calculation methods,basic parameters,and carbon reduction strategies;development suggestions are also proposed.
基金supported by National Natural Science Foundation of China(52100072,52100213)the Fundamental Research FundsfortheCentralUniversities(JZ2021HGTA0159,JZ2021HGQA0212)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA21021101)the Scientific Research Common Program of Beijing Municipal Commission of Education(KM202010017006)the Beijing Natural Science Foundation(8214056)。
文摘There have been many studies on life cycle assessment in sewage treatment,but there are scarce few studies on the treatment of industrial wastewater in combination with advanced oxidation technology,especially in catalytic wet air oxidation(CWAO).There are no cases of using actual industrialized data onto life cycle assessment.This paper uses Simapro 9.0 software to establish a life cycle assessment model for the treatment of high-concentration organic wastewater by CWAO,and comprehensively explains the impact on the environment from three aspects:the construction phase,the operation phase and the demolition phase.In addition,sensitivity analysis and uncertainty analysis were performed.The results showed that the key factors affecting the environment were marine ecotoxicity,mineral resource consumption and global warming,the operation stage had the greatest impact on the environment,which was related to high power consumption during operation and emissions from the treatment process.Sensitivity analysis showed that electricity consumption has the greatest impact on abiotic depletion and freshwater aquatic ecotoxicity,and it also proved that global warming is mainly caused by pollutant emissions during operation phase.Monte Carlo simulations found slightly higher uncertainty for abiotic depletion and toxicity-related impact categories.
文摘The lifecycle greenhouse gas(GHG)emissions(Well-to-Wake)from maritime transport must be reduced by at least 50%in absolute values by 2050 to contribute to the ambitions of the Paris Agreement(2015).A transition from conventional fuels to alternative fuels with zero or lower GHG emissions is viewed as the most promising avenue to reach the GHG reductions.Whereas GHG and toxic pollutants emitted from the use of fossil fuels(heavy fuel oil(HFO)and marine gas/diesel oil(MGO/MDO))are generally well understood,the emissions associated with the new fuel options are only now being measured and communicated.This review provides an outlook on fuels that could help shipping respond to the decarbonization effort including Liquefied Petroleum Gas(LPG),Liquefied Natural Gas(LNG),methanol,ammonia,and hydrogen.A quantification of the pollutants associated from the use of these fuels is provided and challenges and barriers to their uptake are discussed.
基金The authors wish to express their gratitude for the financial supported by the National Key Research and Development Program of China(Grant No.2018YFE0127000)the Young Tip-top Talent Project of Science and Technology Innovation by State Forestry and Grassland Administration of China(Grant No.2019132616)+1 种基金the Agricultural Science and Technology Innovation Drive Project of Shaanxi Province(Grant Nos.NYKJ-2021-YLXN15,K3030821093)the Forestry Science and Technology Development Project by State Forestry and Grassland Administration of China(Grant No.KJZXZZ2019005).
文摘This research undertook a case study of the life-cycle assessment and techno-economic analysis of the slow pyrolysis of Eucommia stem for the production of wood vinegar and activated carbon.The results showed that the production of one ton of wood vinegar via the slow pyrolysis of Eucommia stem show comparatively low global warming potential(2.37×10^(2) kg CO_(2) eq),primary energy demand(3.16×10^(3) MJ),acidification potential(2.19 kg SO2 eq),antimony depletion potential(3.86×10^(–4) kg antimony eq),and ozone depletion potential(7.46×10^(–6) kg CFC-11 eq)and was more environmentally friendly than the production of dilute acetic acid(12 wt%)via petrochemical routes.Meanwhile,the total capital investment,total product cost,and cash flowsheet were provided in the techno-economic analysis.Then,the net present value,internal rate of return,and dynamic payback period of the production process were evaluated.The findings indicated that while this production process is cost-effective,it might not be economically attractive or could generate investment risks.An increase in the added value of the wood vinegar and the activated carbon could remarkably improve the economic feasibility of this production process.
基金supported by the Institute of Information and Communications Technology Planning and Evaluation(IITP)grant funded by the Korean government(MSIT)(No.2022-0-00089,Development of clustering and analysis technology to identify cyber attack groups based on life cycle)the Institute of Civil Military Technology Cooperation funded by the Defense Acquisition Program Administration and Ministry of Trade,Industry and Energy of Korean government under Grant No.21-CM-EC-07.
文摘Cybersecurity increasingly relies on machine learning(ML)models to respond to and detect attacks.However,the rapidly changing data environment makes model life-cycle management after deployment essential.Real-time detection of drift signals from various threats is fundamental for effectively managing deployed models.However,detecting drift in unsupervised environments can be challenging.This study introduces a novel approach leveraging Shapley additive explanations(SHAP),a widely recognized explainability technique in ML,to address drift detection in unsupervised settings.The proposed method incorporates a range of plots and statistical techniques to enhance drift detection reliability and introduces a drift suspicion metric that considers the explanatory aspects absent in the current approaches.To validate the effectiveness of the proposed approach in a real-world scenario,we applied it to an environment designed to detect domain generation algorithms(DGAs).The dataset was obtained from various types of DGAs provided by NetLab.Based on this dataset composition,we sought to validate the proposed SHAP-based approach through drift scenarios that occur when a previously deployed model detects new data types in an environment that detects real-world DGAs.The results revealed that more than 90%of the drift data exceeded the threshold,demonstrating the high reliability of the approach to detect drift in an unsupervised environment.The proposed method distinguishes itself fromexisting approaches by employing explainable artificial intelligence(XAI)-based detection,which is not limited by model or system environment constraints.In conclusion,this paper proposes a novel approach to detect drift in unsupervised ML settings for cybersecurity.The proposed method employs SHAP-based XAI and a drift suspicion metric to improve drift detection reliability.It is versatile and suitable for various realtime data analysis contexts beyond DGA detection environments.This study significantly contributes to theMLcommunity by addressing the critical issue of managing ML models in real-world cybersecurity settings.Our approach is distinguishable from existing techniques by employing XAI-based detection,which is not limited by model or system environment constraints.As a result,our method can be applied in critical domains that require adaptation to continuous changes,such as cybersecurity.Through extensive validation across diverse settings beyond DGA detection environments,the proposed method will emerge as a versatile drift detection technique suitable for a wide range of real-time data analysis contexts.It is also anticipated to emerge as a new approach to protect essential systems and infrastructures from attacks.
基金supported by the National Natural Science Foundation of China(Grant Nos.51878062,52102390 and 52002032)the Natural Science Foundation of Shaanxi Province(Grant No.2022JQ-527)the Fundamental Research Funds for the Central Universities(Grant Nos.300102342501 and 300102342517)
文摘Carbon dioxide(CO_(2))emissions from the road sector have attracted increasing attention in current years.This paper attempted to provide a systematic review of the existing research efforts on road life-cycle CO_(2)emissions by analyzing the system’s boundary division,identifying the CO_(2)emission contributions of each life-cycle phase,listing major emission contributors,exploring related emission reduction technologies,and giving directions for future development.The research showed that the road life cycle is usually divided into five phases:material production,construction,use,maintenance and end-of-life(EOL)phases.The use phase and the initial construction stage(including material production and construction phases)contributed the most CO_(2)emissions during the road life cycle.In detail,the production of cement,asphalt and steel were the three main emission contributors in the material production phase.The pavement roughness,albedo,and concrete carbonation were the main factors affecting emissions in the use phase.In addition,emission reduction technologies such as using recycled materials and recycling techniques,lowering mixing temperature,and equipment energy substitution were commonly used to reduce emissions from material production and construction phases.The application of emerging technologies such as carbon capture and storage,carbon sink,and the use of hydrogen,solar and photovoltaic in the road sector may have emission reduction potentials and should be highlighted more in future studies.
基金co-sponsored by the National Natural Science Foundation of China (71774095, 71690244 and 71673165)the Postdoctoral Science Foundation of China (2017M610096)the International Science and Technology Cooperation Program of China (2016YFE0102200)
文摘This study develops a bottom-up model to quantitatively assess the comprehensive effects of replacing traditional petroleum-powered vehicles with natural gas vehicles(NGVs) in China based on an investigation of the direct energy consumption and critical air pollutant(CAP) emission intensity, life-cycle energy use and greenhouse gas(GHG) emission intensity of NGV fleets. The results indicate that, on average, there are no net energy savings from replacing a traditional fuel vehicle with an NGV. Interestingly, an NGV results in significant reductions in direct CAP and life-cycle GHG emissions compared to those of a traditional fuel vehicle, ranging from 61% to 76% and 12% to 29%, respectively. Due to the increasing use of natural gas as a vehicle fuel in China(i.e. approximately 28.2 billion cubic metres of natural gas in2015), the total petroleum substituted with natural gas was approximately 23.8 million tonnes(Mt), which generated a GHG emission reduction of 16.9 Mt of CO2 equivalent and a CAP emission reduction of 1.8 Mt in 2015. Given the significant contribution of NGVs, growing the NGV population in 2020 will further increase the petroleum substitution benefits and CAP and GHG emission reduction benefits by approximately 42.5 Mt of petroleum-based fuel, 3.1 Mt of CAPs and 28.0 Mt of GHGs. By 2030, these benefits will reach 81.5 Mt of traditional petroleum fuel, 5.6 Mt of CAPs and 50.5 Mt of GHGs, respectively.
基金supported by the Project of Basic Science Center for the National Natural Science Foundation of China(72088101)。
文摘Unconventional oil and gas resources have become the most important and realistic field for increasing China’s domestic oil and gas reserves and production.At present,the production scale does not match the massive amount of resources and the rapid growth of proven geological reserves.The challenges of technology,cost,management,and methodology restrict large-scale and economic development.Based on successful practices,a"one engine with six gears"system engineering methodology is put forward,which includes life-cycle management,overall synergy,interdisciplinary cross-service integration,marketoriented operation,socialized support,digitalized management,and low-carbon and green development.The methodology has been proved to be effective in multiple unconventional oil and gas national demonstration areas,including the Jimusar continental shale oil demonstration area.Disruptive views are introduced-namely,that unconventional oil and gas do not necessarily yield a low return,nor do they necessarily have a low recovery factor.A determination to achieve economic benefit must be a pervasive underlying goal for managers and experts.Return and recovery factors,as primary focuses,must be adhered to during China’s development of unconventional oil and gas.The required methodology transformation includes a revolution in management systems to significantly decrease cost and increase production,resulting in technological innovation.
基金the support from National Natural Science Foundation of China(22078208)the Major Science and Technology Projects of Inner Mongolia Autonomous Region(2020ZD0025)China Chengda Engineering Co.,Ltd.for its software support。
文摘The production of polyvinyl chloride by calcium carbide method is a typical chemical process with high coal consumption,leading to massive flue gas and carbide slag emissions.Currently,the carbide slag with high CaO content is usually stacked in residue field,easily draining away with the rain and corroding the soil.In this work,we coupled the treatment of flue gas and carbide slag to propose a facile CO_(2)mineralization route to prepare light calcium carbonate.And the route feasibility was comprehensively evaluated via experiments and simulation.Through experimental investigation,the Ca^(2+) leaching and mineralization reaction parameters were determined.Based on the experiment,a process was built and optimized through Aspen Plus,and the energy was integrated to obtain the overall process energy and material consumption.Finally,the net CO_(2)emission reduction rate of the entire process through the life-cycle assessment method was analyzed.Moreover,the relationship between the parameters and the CO_(2)emission life-cycle assessment was established.The final optimization results showed that the mineralization process required 1154.69 kW·h·(t CO_(2))^(-1) of energy(including heat energy of 979.32 kW·h·(t CO_(2))^(-1) and electrical energy of 175.37 kW·h·(t CO_(2))^(-1)),and the net CO_(2)emission reduction rate was 35.8%.The light CaCO_(3)product can be sold as a high value-added product.According to preliminary economic analysis,the profit of mineralizing can reach more than 2,100 CNY·(t CO_(2))^(-1).
基金Project(51275362)supported by the National Natural Science Foundation of ChinaProject(2014ZX04015021)supported by National Science and Technology Major Project,China
文摘Product family(PF) is the most important part of product platform. A new method is proposed to mine PF based on multi-space product data in PLM database. Product structure tree(PST) and bill of material(BOM) are used as the data source. A PF can be obtained by mining physics space, logic space and attribute space of product data. In this work, firstly, a PLM database is described, consisting of data organization form, data structure, and data characteristics. Then the PF mining method introduces the sequence alignment techniques used in bio-informatics, which mainly includes data pre-processing, regularization, mining algorithm and cluster analysis. Finally, the feasibility and effectiveness of the proposed method are verified by a case study of high and middle pressure valve, demonstrating a feasible method to obtain PF from PLM database.
文摘Trypanosoma rangeli and T.cruzi are both parasitic unicellular species that infect humans.Unlike T.cruzi,the causative agent of Chagas disease,T.rangeli is an infective and non-pathogenic parasite for humans,but pathogenic for vectors from the Rhodnius genus.Because both species can coexist in different hosts and overlap their infective cycles but very little is known about the infection of T.rangeli in mammalian cells,we decided to characterize both the development of this parasite in cell culture and the effect of therapeutic agents with potential trypanocidal action on it.We found that T.rangeli exhibits a cycle of infection in Vero cells similar to that for T.cruzi and that the repurposed drug,17-AAG,and the natural extract Artemisia sp.essential oil produce a toxic effect on epimastigotes showing a trypanocidal action from the fifth day of culture.Both treatments also affected the infection of trypomastigotes and reduced the capacity of replication of amastigotes of T.rangeli.Since T.cruzi/T.rangeli coinfection cases have been reported,the finding of drugs with potential activity against both species could be significant in the future.Furthermore,studies of susceptibility of both species to drugs could also help to know the different mechanisms of pathogenicity in humans displayed by T.cruzi that are absent in T.rangeli.
基金Project supported by the National Key R&D Program of China(Grant No.2016YFB0700503)the National High Technology Research and Development Program of China(Grant No.2015AA03420)+2 种基金Beijing Municipal Science and Technology Project,China(Grant No.D161100002416001)the National Natural Science Foundation of China(Grant No.51172018)Kennametal Inc
文摘Since its launch in 2011, the Materials Genome Initiative(MGI) has drawn the attention of researchers from academia,government, and industry worldwide. As one of the three tools of the MGI, the use of materials data, for the first time, has emerged as an extremely significant approach in materials discovery. Data science has been applied in different disciplines as an interdisciplinary field to extract knowledge from data. The concept of materials data science has been utilized to demonstrate its application in materials science. To explore its potential as an active research branch in the big data era, a three-tier system has been put forward to define the infrastructure for the classification, curation and knowledge extraction of materials data.