Urbanization has profound impacts on ecological environments. Green spaces are a vital component of urban ecosystems and play a crucial role in maintaining ecological balance and enhancing sustainability. This study a...Urbanization has profound impacts on ecological environments. Green spaces are a vital component of urban ecosystems and play a crucial role in maintaining ecological balance and enhancing sustainability. This study aimed to investigate the community composition characteristics of butterflies in urban green spaces within the context of rapid urbanization. Simultaneously, it explored the status and differences in butterfly taxonomic diversity, functional diversity, and functional traits among different types of urban green spaces, regions, and urban gradients to provide relevant insights for further improving urban green space quality and promoting biodiversity conservation. We conducted a year-long survey of 80 green spaces across different urban regions and ring roads within Hefei City, Anhui Province, with monthly sampling intervals over 187 transects. A total of 4822 butterflies, belonging to 5 families, 17 subfamilies, 40 genera, and 55 species were identified. The species richness, Shannon, Simpson, functional richness, and Rao's quadratic entropy indices of butterflies in urban park green spaces were all significantly higher than those in residential and street green spaces(P < 0.05). Differences in butterfly diversity and functional traits among different urban regions and ring roads were relatively minor, and small-sized, multivoltine, and long flying duration butterflies dominated urban green spaces. Overall, these spaces offer more favorable habitats for butterflies. However, some residential green spaces and street green spaces demonstrate potential for butterfly conservation.展开更多
The high-quality development of the construction industry fundamentally stems from the significant improvement of total factor productivity.Therefore,it is of crucial significance for promoting the development of the ...The high-quality development of the construction industry fundamentally stems from the significant improvement of total factor productivity.Therefore,it is of crucial significance for promoting the development of the construction industry to a higher level by scientifically and accurately measuring the total factor productivity of the construction industry and deeply analyzing the influencing factors behind it.Based on a comprehensive consideration of research methods and influencing factors,this paper systematically reviews the existing relevant literature on total factor productivity in the construction industry,aiming to reveal the current research development trend in this field and point out potential problems.This effort aims to provide a solid theoretical foundation and valuable reference for further in-depth research,and jointly promote the continuous progress and development of total factor productivity research in the construction industry.展开更多
Green and low-carbon development of construction industry is one of the important ways to achieve the"dual carbon"goal in China.This study first measured the carbon emissions of the construction industry in ...Green and low-carbon development of construction industry is one of the important ways to achieve the"dual carbon"goal in China.This study first measured the carbon emissions of the construction industry in 30 provinces in China,and then used the Dagum Gini coefficient and its decomposition method to explore the regional differences and sources of carbon emissions of the construction industry in China.The results show that the carbon emissions of construction industry in China generally show an upward trend,and there are significant differences in carbon emissions of construction industry among provinces,and the main source of regional differences is inter-regional differences.However,the contribution rate of inter-regional differences showed a significant downward trend,while the contribution rate of hyperbolic density increased day by day,and the contribution rate of intra-regional differences increased slightly.The results of this study will provide a reference for China to formulate more reasonable carbon emission reduction targets and differentiation strategies for the construction industry.展开更多
The entry of collective construction land for business purposes is an important measure for deepening the reform of the rural land system,promoting the flow of urban and rural factors,and realizing rural revitalizatio...The entry of collective construction land for business purposes is an important measure for deepening the reform of the rural land system,promoting the flow of urban and rural factors,and realizing rural revitalization.Since the production of the first batch of pilot projects in 2015,33 county-level cities have participated in the pilot policy by 2023.Deqing County,Zhejiang Province,as the first area to participate in the pilot project,aims to achieve more fruitful results.This paper first examines how promoting farmers’income through the market entry of agricultural land can be achieved,then uses the synthetic control method to quantitatively study the impact of collective operational construction land on farmers’income using panel data from 2011 to 2019,and finally proposes relevant suggestions from the perspective of system reform.展开更多
This study aims to investigate the feasibility of using decoration waste powder(DWP)as a partial replacement for fly ash(FA)in the preparation of geopolymer masonry mortar,and to examine the effect of different DWP re...This study aims to investigate the feasibility of using decoration waste powder(DWP)as a partial replacement for fly ash(FA)in the preparation of geopolymer masonry mortar,and to examine the effect of different DWP replacement rates(0%-40%)on the fresh and mechanical properties of the mortar.The results showed that each group of geopolymer masonry mortar exhibited excellent water retention performance,with a water retention rate of 100%,which was due to the unique geopolymer mortar system and high viscosity of the alkaline activator solution.Compared to the control group,the flowability of the mortar containing lower contents of DWP(10%and 20%)was higher.However,as the DWP replacement rate further increased,the flowability gradually decreased.The DWP could absorb the free water in the reaction system of geopolymer mortar,thereby limiting the occurrence of geopolymerization reaction.The incorporation of DWP in the mortar resulted in a decrease in compressive strength compared to the mortar without DWP.However,even at a replacement rate of 40%,the compressive strength of the mortar still exceeded 15 MPa,which met the requirements of the masonry mortar.It was feasible to use DWP in the geopolymer masonry mortar.Although the addition of DWP caused some performance loss,it did not affect its usability.展开更多
The deformation and fracture evolution mechanisms of the strata overlying mines mined using sublevel caving were studied via numerical simulations.Moreover,an expression for the normal force acting on the side face of...The deformation and fracture evolution mechanisms of the strata overlying mines mined using sublevel caving were studied via numerical simulations.Moreover,an expression for the normal force acting on the side face of a steeply dipping superimposed cantilever beam in the surrounding rock was deduced based on limit equilibrium theory.The results show the following:(1)surface displacement above metal mines with steeply dipping discontinuities shows significant step characteristics,and(2)the behavior of the strata as they fail exhibits superimposition characteristics.Generally,failure first occurs in certain superimposed strata slightly far from the goaf.Subsequently,with the constant downward excavation of the orebody,the superimposed strata become damaged both upwards away from and downwards toward the goaf.This process continues until the deep part of the steeply dipping superimposed strata forms a large-scale deep fracture plane that connects with the goaf.The deep fracture plane generally makes an angle of 12°-20°with the normal to the steeply dipping discontinuities.The effect of the constant outward transfer of strata movement due to the constant outward failure of the superimposed strata in the metal mines with steeply dipping discontinuities causes the scope of the strata movement in these mines to be larger than expected.The strata in the metal mines with steeply dipping discontinuities mainly show flexural toppling failure.However,the steeply dipping structural strata near the goaf mainly exhibit shear slipping failure,in which case the mechanical model used to describe them can be simplified by treating them as steeply dipping superimposed cantilever beams.By taking the steeply dipping superimposed cantilever beam that first experiences failure as the key stratum,the failure scope of the strata(and criteria for the stability of metal mines with steeply dipping discontinuities mined using sublevel caving)can be obtained via iterative computations from the key stratum,moving downward toward and upwards away from the goaf.展开更多
Underground engineering often passes through water-rich fractured rock masses, which are prone to fracture and instability under the long-term coupling of in-situ stress field and pore water(P-W) pressure, ultimately ...Underground engineering often passes through water-rich fractured rock masses, which are prone to fracture and instability under the long-term coupling of in-situ stress field and pore water(P-W) pressure, ultimately threatening the stability of underground structures. In order to explore the mechanical properties of rocks under H-M coupling, the corresponding damage constitutive(D-C) model has become the focus of attention. Considering the inadequacy of the current research on rock strength parameters,energy evolution characteristics and D-C model under H-M coupling, the mechanical properties of typical sandstone samples are discussed based on laboratory tests. The results show that the variation of characteristic stresses of sandstone under H-M coupling conforms to the normalized attenuation equation and Mohr-Coulomb(M-C) criterion. The P-W pressure mechanism of sandstone exhibits a dynamic change from softening effect to H-M fracturing effect. The closure stress is mainly provided by cohesive strength, while the initiation stress, damage stress, and peak stress are jointly dominated by cohesive strength and friction strength. In addition, residual stress is attributed to the friction strength formed by the bite of the fracture surface. Subsequently, the energy evolution characteristics of sandstone under H-M coupling were studied, and it was found that P-W pressure weakened the energy storage capacity and energy dissipation capacity of sandstone, and H-M fracturing was an important factor in reducing its energy storage efficiency. Finally, combined with energy dissipation theory and statistical damage theory, two types of D-C models considering P-W pressure are proposed accordingly, and the model parameters can be determined by four methods. The application results indicate that the proposed and modified D-C models have high reliability, and can characterize the mechanical behavior of sandstone under H-M coupling, overcome the inconvenience of existing D-C models due to excessive mechanical parameters,and can be applied to the full-range stress–strain process. The results are conducive to revealing the deformation and damage mechanisms of rocks under H-M coupling, and can provide theoretical guidance for related engineering problems.展开更多
As socioeconomic development continues,the issue of building energy consumption has attracted significant attention,and improving the thermal insulation performance of buildings has become a crucial strategic measure....As socioeconomic development continues,the issue of building energy consumption has attracted significant attention,and improving the thermal insulation performance of buildings has become a crucial strategic measure.Simultaneously,the application of solid waste in insulation materials has also become a hot topic.This paper reviews the sources and classifications of solid waste,focusing on research progress in its application as insulation materials in the domains of daily life,agriculture,and industry.The research shows that incorporating household solid waste materials,such as waste glass,paper,and clothing scraps into cementitious thermal insulation can significantly reduce the thermal conductivity of the materials,leading to excellent thermal insulation properties.Insulation materials prepared from agricultural solid waste,such as barley straw,corn stalk,chicken feather,and date palm fibers,possess characteristics of lightweight and strong thermal insulation.Industrial solid waste,including waste tires,iron tailings,and coal bottom ash,can also be utilized in the preparation of insulation materials.These innovative applications not only have positive environmental significance by reducing waste emissions and resource consumption,but also provide efficient and sustainable insulation solutions for the construction industry.However,to further optimize the mix design and enhance the durability of insulation materials,continuous research is required to investigate the mechanisms through which solid waste impacts the performance of insulation materials.展开更多
Feixi County has made significant progress in promoting waste classification,such as establishing a comprehensive classification system,and effectively reducing environmental pollution and waste volume.However,with th...Feixi County has made significant progress in promoting waste classification,such as establishing a comprehensive classification system,and effectively reducing environmental pollution and waste volume.However,with the increase in waste generation,the county faces multiple challenges especially in the disposal of kitchen waste and improvement of residents environmental awareness.To address these issues,Feixi County has implemented various measures,such as strengthening the construction of infrastructure for waste classification,improving regulations and clearly defining responsibilities,enhancing residents environmental awareness to encourage their participation in waste classification through education and promotion,and increasing supervision to ensure effective implementation of the work.It emphasizes community governance,encourage all parties to participate in it,and strengthen publicity,education and training to enhance residents participation.Feixi County has achieved positive results,but efforts are needed to further improve facilities,raise awareness,enhance supervision,and ensure the continuous effectiveness of waste classification work to promote urban green sustainable development.展开更多
This paper mainly introduces the research progress on interface failure behavior in high-temperature alloy surface thermal barrier coating systems.The degradation failure and structural evolution behavior during high-...This paper mainly introduces the research progress on interface failure behavior in high-temperature alloy surface thermal barrier coating systems.The degradation failure and structural evolution behavior during high-temperature service were analyzed for the matrix/bonding layer interface,bonding layer/TGO interface,and TGO/ceramic layer interface in thermal barrier coatings.The research focus and direction that affect the interface performance of thermal barrier coatings were proposed.展开更多
Urban Parks play an important role in the urban ecological environment. Based on the profound effect of ecological ideology on urban park design, we stud- ied the evolution course of ecological ideology and the charac...Urban Parks play an important role in the urban ecological environment. Based on the profound effect of ecological ideology on urban park design, we stud- ied the evolution course of ecological ideology and the characteristics of the ecological ideology at different stages in the United States, and emphatically introduced the influence of ecological ideology on the planning and design of New York Central Park, with the aim to summarize the inspiration for the urban park design in China.展开更多
Fuzzy mathematics comprehensive evaluation method is used to evaluate the geological environment suitability of rural urbanization in Qingdao City,China.A total of 5 first-level evaluation factors are selected,includi...Fuzzy mathematics comprehensive evaluation method is used to evaluate the geological environment suitability of rural urbanization in Qingdao City,China.A total of 5 first-level evaluation factors are selected,including environmental geological condition,geological resources,engineering geological condition,geological disaster and environmental geological problem,and human engineering activity.And there are 27 second-level evaluation factors,such as topography,land type and vegetation,nature reserve,water source protection area,groundwater quality division,and major engineering project.Qingdao City is divided into four districts of suitable area,relatively suitable area,moderately suitable area and relatively unsuitable area of ecological environment.And their characteristics are introduced.Suggestions for the developing direction of urban construction are put forward.Region of Laoshan District lying to the west of the Shilaoren is suitable to set up high-rise building;west Hongshiya may establish a waste landfill site;Jiaozhou Bay,the downstream of Dagu River,and Jihongtan Reservoir should be built as the key geological environment protection area and water source protection area.And the north Hongdao should be strictly monitored in order to control the expansion of urban construction to Jihongtan Reservoir.Mocheng District and the area north of it,Jiaozhou District and the area east of it are the ideal urban construction development areas in Qingdao City in the future.展开更多
Two critical factors,namely intense precipitation and intricate excavation,can trigger rock mass disasters in mining operations.In this study,an indoor rainfall system was developed to precisely regulate the flow and ...Two critical factors,namely intense precipitation and intricate excavation,can trigger rock mass disasters in mining operations.In this study,an indoor rainfall system was developed to precisely regulate the flow and intensity of precipitation.A large-scale model experiment was conducted on a self-designed physical simulation experiment platform to investigate the failure and instability of high-steep rock slopes under unsaturated conditions.The real-time reproduction of the progressive failure process in high-steep rock slopes enabled the determination of the critical rainfall intensity and revealed the mechanism underlying slope instability.Experiment results indicated that rainfall may be the primary factor contributing to rock mass instability,while continuous pillar mining exacerbates the extent of rock mass failure.The critical failure stage of high-steep rock slopes occurs at a rainfall intensity of 40 mm/h,whereas a rainfall exceeding 50 mm can induce critical instability and precipitation reaching up to 60 mm will result in slope failure.The improved region growing segmentation method(IRGSM)was subsequently employed for image recognition of rock mass deformation in underground mines.Herein an error comparison with the simple linear iterative cluster(SLIC)superpixel method and the original region growing segmentation method(ORGSM)showed that the average identification error in the X and Y directions by the method was reduced significantly(1.82%and 1.80%in IRGSM;4.70%and 6.26%in SLIC;9.45%and 12.40%in ORGSM).Ultimately,the relationship between rainfall intensity and failure probability was analyzed using the Monte Carlo method.Moreover,the stability assessment criteria of rock slope under unsaturated condition were quantitatively and accurately evaluated.展开更多
Due to the loose structure,high porosity and high permeability of soil-rock mixture slope,the slope is unstable and may cause huge economic losses and casualties.The h-type anti-slide pile is regarded as an effective ...Due to the loose structure,high porosity and high permeability of soil-rock mixture slope,the slope is unstable and may cause huge economic losses and casualties.The h-type anti-slide pile is regarded as an effective means to prevent the instability of soilrock mixture slope.In this paper,a centrifuge model test was conducted to investigate the stress distribution of the h-type anti-slide pile and the evolution process of soil arching during the loading.A numerical simulation model was built based on the similar relationship between the centrifuge model and the prototype to investigate the influence factors of the pile spacing,anchored depth,and crossbeam stiffness,and some recommendations were proposed for its application.The results show that the bending moment distribution of the rear pile exhibits Wshaped,while for the front pile,its distribution resembles V-shaped.The soil arching evolution process during loading is gradually dissipated from bottom to top and from far to near.During the loading,the change of bending moment can be divided into three stages,namely,the stabilization stage,the slow growth stage,and the rapid growth stage.In engineering projects,the recommended values of the pile spacing,anchored depth,and crossbeam stiffness are 4.0d,2.0d,and 2.0EI,where d and EI are the diameter and bending stiffness of the h-type anti-slide pile respectively.展开更多
On the basis of reviewing urban design and management practices of Honggutan New District in Nanchang City, Jiangxi Province, regulatory urban design was proposed and its major feature was summarized as "the loca...On the basis of reviewing urban design and management practices of Honggutan New District in Nanchang City, Jiangxi Province, regulatory urban design was proposed and its major feature was summarized as "the local government or urban management agency responsible for the organization and compiling". After defining regulatory urban design, its compiling and technical means were studied.展开更多
This paper introduced concept and modern thought of urban brownfield site and flexible landscape design, analyzed factors influencing the modernity, and pointed out significance and necessity of flexible landscape des...This paper introduced concept and modern thought of urban brownfield site and flexible landscape design, analyzed factors influencing the modernity, and pointed out significance and necessity of flexible landscape design. By analyzing realistic problems of urban brownfield site, this paper combined flexible design and renovation of brownfield landscape renovation, and proposed suggestions for the flexible landscape renovation of urban brownfield sites, so that renovation of urban brownfield landscape is not confined in renovation, but is more flexible and adaptive, and flexible design is positive for the renovation of urban brownfield landscapes.展开更多
This paper analyzed current situation of domestic and foreign children's outdoor spaces, and the relationship between urban public spaces and children's behaviors, summarized design principles and techniques t...This paper analyzed current situation of domestic and foreign children's outdoor spaces, and the relationship between urban public spaces and children's behaviors, summarized design principles and techniques to improve use efficiency of urban outdoor public spaces and facilities, create public spaces capable of meeting psychological behavior needs of children.展开更多
Based on the background that wetland resources in China are under threat and urgently need to be protected,a series of rainwater and flood problems caused by urban construction is analyzed comprehensively,and the desi...Based on the background that wetland resources in China are under threat and urgently need to be protected,a series of rainwater and flood problems caused by urban construction is analyzed comprehensively,and the design and planning methods of wetland parks in response to rainwater and flood disasters caused by floods and heavy rainfall are explored.Southern Anhui with complex and variable terrain and frequent rainfall and flood disasters is selected as the research area,with Xuanzhou District of Xuancheng City as the main research object.The relationship between municipal drainage of urban park and water conservancy drainage is investigated from different sample selection,design samples,and design flow rates.Based on literature review and model building methods,an urban storm flood model suitable for typical wetland parks in southern Anhui is constructed after processing the survey data using Arc GIS,SWMM(storm water management model).On this basis,a methodology and principles for designing a sponge system of wetland park based on rainwater and flood control are proposed,including technical measures such as rainwater collection,retention,and purification.This paper provides certain research results in design schemes,effect evaluations,ecological and social benefits,and useful suggestions and solutions for urban stormwater management and resilience development.展开更多
Dredged marine soils(DMS)have poor engineering properties,which limit their usage in construction projects.This research examines the application of reactive magnesia(rMgO)containing supplementary cementitious materia...Dredged marine soils(DMS)have poor engineering properties,which limit their usage in construction projects.This research examines the application of reactive magnesia(rMgO)containing supplementary cementitious materials(SCMs)to stabilize DMS under ambient and carbon dioxide(CO_(2))curing conditions.Several proprietary experimental tests were conducted to investigate the stabilized DMS.Furthermore,the carbonation-induced mineralogical,thermal,and microstructural properties change of the samples were explored.The findings show that the compressive strength of the stabilized DMS fulfilled the 7-d requirement(0.7-2.1 MPa)for pavement and building foundations.Replacing rMgO with SCMs such as biochar or ground granulated blast-furnace slag(GGBS)altered the engineering properties and particle packing of the stabilized soils,thus influencing their performances.Biochar increased the porosity of the samples,facilitating higher CO_(2) uptake and improved ductility,while GGBS decreased porosity and increased the dry density of the samples,resulting in higher strength.The addition of SCMs also enhanced the water retention capacity and modified the pH of the samples.Microstructural analysis revealed that the hydrated magnesium carbonates precipitated in the carbonated samples provided better cementation effects than brucite formed during rMgO hydration.Moreover,incorporating SCMs reduced the overall global warming potential and energy demand of the rMgO-based systems.The biochar mixes demonstrated lower toxicity and energy consumption.Ultimately,the rMgO and biochar blend can serve as an environmentally friendly additive for soft soil stabilization and permanent fixation of significant amounts of CO_(2) in soils through mineral carbonation,potentially reducing environmental pollution while meeting urbanization needs.展开更多
To investigate how the physicochemical properties and NH3‐selective catalytic reduction(NH3‐SCR)performance of supported ceria‐based catalysts are influenced as a function of support type,a series of CeO2/SiO2,CeO2...To investigate how the physicochemical properties and NH3‐selective catalytic reduction(NH3‐SCR)performance of supported ceria‐based catalysts are influenced as a function of support type,a series of CeO2/SiO2,CeO2/γ‐Al2O3,CeO2/ZrO2,and CeO2/TiO2catalysts were prepared.The physicochemical properties were probed by means of X‐ray diffraction,Raman spectroscopy,Brunauer‐Emmett‐Teller surface area measurements,X‐ray photoelectron spectroscopy,H2‐temperature programmed reduction,and NH3‐temperature programmed desorption.Furthermore,the supported ceria‐based catalysts'catalytic performance and H2O+SO2tolerance were evaluated by the NH3‐SCR model reaction.The results indicate that out of the supported ceria‐based catalysts studied,the CeO2/γ‐Al2O3catalyst exhibits the highest catalytic activity as a result of having a high relative Ce3+/Ce4+ratio,optimum reduction behavior,and the largest total acid site concentration.Finally,the CeO2/γ‐Al2O3catalyst also presents excellent H2O+SO2tolerance during the NH3‐SCR process.展开更多
基金funded by the National Non Profit Research Institutions of the Chinese Academy of Forestry(CAFYBB2020ZB008)National Natural Science Foundation of China(32371936)the Research Projects in Anhui Universities in 2022(natural sciences)(2022AH051874).
文摘Urbanization has profound impacts on ecological environments. Green spaces are a vital component of urban ecosystems and play a crucial role in maintaining ecological balance and enhancing sustainability. This study aimed to investigate the community composition characteristics of butterflies in urban green spaces within the context of rapid urbanization. Simultaneously, it explored the status and differences in butterfly taxonomic diversity, functional diversity, and functional traits among different types of urban green spaces, regions, and urban gradients to provide relevant insights for further improving urban green space quality and promoting biodiversity conservation. We conducted a year-long survey of 80 green spaces across different urban regions and ring roads within Hefei City, Anhui Province, with monthly sampling intervals over 187 transects. A total of 4822 butterflies, belonging to 5 families, 17 subfamilies, 40 genera, and 55 species were identified. The species richness, Shannon, Simpson, functional richness, and Rao's quadratic entropy indices of butterflies in urban park green spaces were all significantly higher than those in residential and street green spaces(P < 0.05). Differences in butterfly diversity and functional traits among different urban regions and ring roads were relatively minor, and small-sized, multivoltine, and long flying duration butterflies dominated urban green spaces. Overall, these spaces offer more favorable habitats for butterflies. However, some residential green spaces and street green spaces demonstrate potential for butterfly conservation.
基金Supported by School-level Natural Science Project of Jiangxi University of Technology(232ZRYB02).
文摘The high-quality development of the construction industry fundamentally stems from the significant improvement of total factor productivity.Therefore,it is of crucial significance for promoting the development of the construction industry to a higher level by scientifically and accurately measuring the total factor productivity of the construction industry and deeply analyzing the influencing factors behind it.Based on a comprehensive consideration of research methods and influencing factors,this paper systematically reviews the existing relevant literature on total factor productivity in the construction industry,aiming to reveal the current research development trend in this field and point out potential problems.This effort aims to provide a solid theoretical foundation and valuable reference for further in-depth research,and jointly promote the continuous progress and development of total factor productivity research in the construction industry.
基金Supported by School-level Natural Science Project of Jiangxi University of Technology(232ZRYB02).
文摘Green and low-carbon development of construction industry is one of the important ways to achieve the"dual carbon"goal in China.This study first measured the carbon emissions of the construction industry in 30 provinces in China,and then used the Dagum Gini coefficient and its decomposition method to explore the regional differences and sources of carbon emissions of the construction industry in China.The results show that the carbon emissions of construction industry in China generally show an upward trend,and there are significant differences in carbon emissions of construction industry among provinces,and the main source of regional differences is inter-regional differences.However,the contribution rate of inter-regional differences showed a significant downward trend,while the contribution rate of hyperbolic density increased day by day,and the contribution rate of intra-regional differences increased slightly.The results of this study will provide a reference for China to formulate more reasonable carbon emission reduction targets and differentiation strategies for the construction industry.
文摘The entry of collective construction land for business purposes is an important measure for deepening the reform of the rural land system,promoting the flow of urban and rural factors,and realizing rural revitalization.Since the production of the first batch of pilot projects in 2015,33 county-level cities have participated in the pilot policy by 2023.Deqing County,Zhejiang Province,as the first area to participate in the pilot project,aims to achieve more fruitful results.This paper first examines how promoting farmers’income through the market entry of agricultural land can be achieved,then uses the synthetic control method to quantitatively study the impact of collective operational construction land on farmers’income using panel data from 2011 to 2019,and finally proposes relevant suggestions from the perspective of system reform.
基金Funded by the National Natural Science Foundation of China(No.52008046)Young Elite Scientists Sponsorship Program from JSAST(No.TJ-2023-024)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX21_2848)。
文摘This study aims to investigate the feasibility of using decoration waste powder(DWP)as a partial replacement for fly ash(FA)in the preparation of geopolymer masonry mortar,and to examine the effect of different DWP replacement rates(0%-40%)on the fresh and mechanical properties of the mortar.The results showed that each group of geopolymer masonry mortar exhibited excellent water retention performance,with a water retention rate of 100%,which was due to the unique geopolymer mortar system and high viscosity of the alkaline activator solution.Compared to the control group,the flowability of the mortar containing lower contents of DWP(10%and 20%)was higher.However,as the DWP replacement rate further increased,the flowability gradually decreased.The DWP could absorb the free water in the reaction system of geopolymer mortar,thereby limiting the occurrence of geopolymerization reaction.The incorporation of DWP in the mortar resulted in a decrease in compressive strength compared to the mortar without DWP.However,even at a replacement rate of 40%,the compressive strength of the mortar still exceeded 15 MPa,which met the requirements of the masonry mortar.It was feasible to use DWP in the geopolymer masonry mortar.Although the addition of DWP caused some performance loss,it did not affect its usability.
基金Financial support for this work was provided by the Youth Fund Program of the National Natural Science Foundation of China (No. 42002292)the General Program of the National Natural Science Foundation of China (No. 42377175)the General Program of the Hubei Provincial Natural Science Foundation, China (No. 2023AFB631)
文摘The deformation and fracture evolution mechanisms of the strata overlying mines mined using sublevel caving were studied via numerical simulations.Moreover,an expression for the normal force acting on the side face of a steeply dipping superimposed cantilever beam in the surrounding rock was deduced based on limit equilibrium theory.The results show the following:(1)surface displacement above metal mines with steeply dipping discontinuities shows significant step characteristics,and(2)the behavior of the strata as they fail exhibits superimposition characteristics.Generally,failure first occurs in certain superimposed strata slightly far from the goaf.Subsequently,with the constant downward excavation of the orebody,the superimposed strata become damaged both upwards away from and downwards toward the goaf.This process continues until the deep part of the steeply dipping superimposed strata forms a large-scale deep fracture plane that connects with the goaf.The deep fracture plane generally makes an angle of 12°-20°with the normal to the steeply dipping discontinuities.The effect of the constant outward transfer of strata movement due to the constant outward failure of the superimposed strata in the metal mines with steeply dipping discontinuities causes the scope of the strata movement in these mines to be larger than expected.The strata in the metal mines with steeply dipping discontinuities mainly show flexural toppling failure.However,the steeply dipping structural strata near the goaf mainly exhibit shear slipping failure,in which case the mechanical model used to describe them can be simplified by treating them as steeply dipping superimposed cantilever beams.By taking the steeply dipping superimposed cantilever beam that first experiences failure as the key stratum,the failure scope of the strata(and criteria for the stability of metal mines with steeply dipping discontinuities mined using sublevel caving)can be obtained via iterative computations from the key stratum,moving downward toward and upwards away from the goaf.
基金funding support from the National Natural Science Foundation of China(Nos.52174088 and 42277154)the Independent Innovation Research Fund Graduate Free Exploration Project(No.104972024JYS0007)supported by Wuhan University of Technology.
文摘Underground engineering often passes through water-rich fractured rock masses, which are prone to fracture and instability under the long-term coupling of in-situ stress field and pore water(P-W) pressure, ultimately threatening the stability of underground structures. In order to explore the mechanical properties of rocks under H-M coupling, the corresponding damage constitutive(D-C) model has become the focus of attention. Considering the inadequacy of the current research on rock strength parameters,energy evolution characteristics and D-C model under H-M coupling, the mechanical properties of typical sandstone samples are discussed based on laboratory tests. The results show that the variation of characteristic stresses of sandstone under H-M coupling conforms to the normalized attenuation equation and Mohr-Coulomb(M-C) criterion. The P-W pressure mechanism of sandstone exhibits a dynamic change from softening effect to H-M fracturing effect. The closure stress is mainly provided by cohesive strength, while the initiation stress, damage stress, and peak stress are jointly dominated by cohesive strength and friction strength. In addition, residual stress is attributed to the friction strength formed by the bite of the fracture surface. Subsequently, the energy evolution characteristics of sandstone under H-M coupling were studied, and it was found that P-W pressure weakened the energy storage capacity and energy dissipation capacity of sandstone, and H-M fracturing was an important factor in reducing its energy storage efficiency. Finally, combined with energy dissipation theory and statistical damage theory, two types of D-C models considering P-W pressure are proposed accordingly, and the model parameters can be determined by four methods. The application results indicate that the proposed and modified D-C models have high reliability, and can characterize the mechanical behavior of sandstone under H-M coupling, overcome the inconvenience of existing D-C models due to excessive mechanical parameters,and can be applied to the full-range stress–strain process. The results are conducive to revealing the deformation and damage mechanisms of rocks under H-M coupling, and can provide theoretical guidance for related engineering problems.
基金funded by the National Natural Science Foundation of China (52078068)Postgraduate Research&Practice Innovation Program of Jiangsu Province (SJCX22_1391)+1 种基金the National Science Foundation of Jiangsu Province (BK20220626)Changzhou Leading Innovative Talent Introduction and Cultivation Project (CQ20210085).
文摘As socioeconomic development continues,the issue of building energy consumption has attracted significant attention,and improving the thermal insulation performance of buildings has become a crucial strategic measure.Simultaneously,the application of solid waste in insulation materials has also become a hot topic.This paper reviews the sources and classifications of solid waste,focusing on research progress in its application as insulation materials in the domains of daily life,agriculture,and industry.The research shows that incorporating household solid waste materials,such as waste glass,paper,and clothing scraps into cementitious thermal insulation can significantly reduce the thermal conductivity of the materials,leading to excellent thermal insulation properties.Insulation materials prepared from agricultural solid waste,such as barley straw,corn stalk,chicken feather,and date palm fibers,possess characteristics of lightweight and strong thermal insulation.Industrial solid waste,including waste tires,iron tailings,and coal bottom ash,can also be utilized in the preparation of insulation materials.These innovative applications not only have positive environmental significance by reducing waste emissions and resource consumption,but also provide efficient and sustainable insulation solutions for the construction industry.However,to further optimize the mix design and enhance the durability of insulation materials,continuous research is required to investigate the mechanisms through which solid waste impacts the performance of insulation materials.
基金Supported by the School-Level Natural Science Project of Anhui Xinhua University(2023zr008)Innovation and Entrepreneurship Training Program for College Students of Anhui Province(S202312216114)+1 种基金Natural Key Scientific Research Project of Anhui Provincial Department of Education(2022AH05187)Anhui University Natural Science Outstanding Research and Innovation Team Project(2023AH010059).
文摘Feixi County has made significant progress in promoting waste classification,such as establishing a comprehensive classification system,and effectively reducing environmental pollution and waste volume.However,with the increase in waste generation,the county faces multiple challenges especially in the disposal of kitchen waste and improvement of residents environmental awareness.To address these issues,Feixi County has implemented various measures,such as strengthening the construction of infrastructure for waste classification,improving regulations and clearly defining responsibilities,enhancing residents environmental awareness to encourage their participation in waste classification through education and promotion,and increasing supervision to ensure effective implementation of the work.It emphasizes community governance,encourage all parties to participate in it,and strengthen publicity,education and training to enhance residents participation.Feixi County has achieved positive results,but efforts are needed to further improve facilities,raise awareness,enhance supervision,and ensure the continuous effectiveness of waste classification work to promote urban green sustainable development.
文摘This paper mainly introduces the research progress on interface failure behavior in high-temperature alloy surface thermal barrier coating systems.The degradation failure and structural evolution behavior during high-temperature service were analyzed for the matrix/bonding layer interface,bonding layer/TGO interface,and TGO/ceramic layer interface in thermal barrier coatings.The research focus and direction that affect the interface performance of thermal barrier coatings were proposed.
文摘Urban Parks play an important role in the urban ecological environment. Based on the profound effect of ecological ideology on urban park design, we stud- ied the evolution course of ecological ideology and the characteristics of the ecological ideology at different stages in the United States, and emphatically introduced the influence of ecological ideology on the planning and design of New York Central Park, with the aim to summarize the inspiration for the urban park design in China.
文摘Fuzzy mathematics comprehensive evaluation method is used to evaluate the geological environment suitability of rural urbanization in Qingdao City,China.A total of 5 first-level evaluation factors are selected,including environmental geological condition,geological resources,engineering geological condition,geological disaster and environmental geological problem,and human engineering activity.And there are 27 second-level evaluation factors,such as topography,land type and vegetation,nature reserve,water source protection area,groundwater quality division,and major engineering project.Qingdao City is divided into four districts of suitable area,relatively suitable area,moderately suitable area and relatively unsuitable area of ecological environment.And their characteristics are introduced.Suggestions for the developing direction of urban construction are put forward.Region of Laoshan District lying to the west of the Shilaoren is suitable to set up high-rise building;west Hongshiya may establish a waste landfill site;Jiaozhou Bay,the downstream of Dagu River,and Jihongtan Reservoir should be built as the key geological environment protection area and water source protection area.And the north Hongdao should be strictly monitored in order to control the expansion of urban construction to Jihongtan Reservoir.Mocheng District and the area north of it,Jiaozhou District and the area east of it are the ideal urban construction development areas in Qingdao City in the future.
基金the Research Fund of National Natural Science Foundation of China(NSFC)(No.42277154)the project supported by graduate research and innovation foundation of Chongqing,China(No.CYB22023)+3 种基金Guizhou Province Science and Technology Planning Project(No.Guizhou science and technology cooperation support[2022]common 229)National Natural Science Foundation of Shandong Province of China(NSFC)(No.ZR2022ME188)the State Key Laboratory of Coal Resources and Safe Mining,CUMT(No.SKLCRSM22KF009)Open Fund of National Engineering and Technology Research Center for Development and Utilization of Phosphate Resources of China(No.NECP 2022-04).
文摘Two critical factors,namely intense precipitation and intricate excavation,can trigger rock mass disasters in mining operations.In this study,an indoor rainfall system was developed to precisely regulate the flow and intensity of precipitation.A large-scale model experiment was conducted on a self-designed physical simulation experiment platform to investigate the failure and instability of high-steep rock slopes under unsaturated conditions.The real-time reproduction of the progressive failure process in high-steep rock slopes enabled the determination of the critical rainfall intensity and revealed the mechanism underlying slope instability.Experiment results indicated that rainfall may be the primary factor contributing to rock mass instability,while continuous pillar mining exacerbates the extent of rock mass failure.The critical failure stage of high-steep rock slopes occurs at a rainfall intensity of 40 mm/h,whereas a rainfall exceeding 50 mm can induce critical instability and precipitation reaching up to 60 mm will result in slope failure.The improved region growing segmentation method(IRGSM)was subsequently employed for image recognition of rock mass deformation in underground mines.Herein an error comparison with the simple linear iterative cluster(SLIC)superpixel method and the original region growing segmentation method(ORGSM)showed that the average identification error in the X and Y directions by the method was reduced significantly(1.82%and 1.80%in IRGSM;4.70%and 6.26%in SLIC;9.45%and 12.40%in ORGSM).Ultimately,the relationship between rainfall intensity and failure probability was analyzed using the Monte Carlo method.Moreover,the stability assessment criteria of rock slope under unsaturated condition were quantitatively and accurately evaluated.
基金supported by the National Natural Science Foundation of China(Grant Nos.41672273,42177137)the Fundamental Research Funds for the Central Universities(22120180313)+1 种基金the support from China Scholarship Council(CSC)(202106260151)substantially supported by the Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education(Tongji University)。
文摘Due to the loose structure,high porosity and high permeability of soil-rock mixture slope,the slope is unstable and may cause huge economic losses and casualties.The h-type anti-slide pile is regarded as an effective means to prevent the instability of soilrock mixture slope.In this paper,a centrifuge model test was conducted to investigate the stress distribution of the h-type anti-slide pile and the evolution process of soil arching during the loading.A numerical simulation model was built based on the similar relationship between the centrifuge model and the prototype to investigate the influence factors of the pile spacing,anchored depth,and crossbeam stiffness,and some recommendations were proposed for its application.The results show that the bending moment distribution of the rear pile exhibits Wshaped,while for the front pile,its distribution resembles V-shaped.The soil arching evolution process during loading is gradually dissipated from bottom to top and from far to near.During the loading,the change of bending moment can be divided into three stages,namely,the stabilization stage,the slow growth stage,and the rapid growth stage.In engineering projects,the recommended values of the pile spacing,anchored depth,and crossbeam stiffness are 4.0d,2.0d,and 2.0EI,where d and EI are the diameter and bending stiffness of the h-type anti-slide pile respectively.
文摘On the basis of reviewing urban design and management practices of Honggutan New District in Nanchang City, Jiangxi Province, regulatory urban design was proposed and its major feature was summarized as "the local government or urban management agency responsible for the organization and compiling". After defining regulatory urban design, its compiling and technical means were studied.
文摘This paper introduced concept and modern thought of urban brownfield site and flexible landscape design, analyzed factors influencing the modernity, and pointed out significance and necessity of flexible landscape design. By analyzing realistic problems of urban brownfield site, this paper combined flexible design and renovation of brownfield landscape renovation, and proposed suggestions for the flexible landscape renovation of urban brownfield sites, so that renovation of urban brownfield landscape is not confined in renovation, but is more flexible and adaptive, and flexible design is positive for the renovation of urban brownfield landscapes.
文摘This paper analyzed current situation of domestic and foreign children's outdoor spaces, and the relationship between urban public spaces and children's behaviors, summarized design principles and techniques to improve use efficiency of urban outdoor public spaces and facilities, create public spaces capable of meeting psychological behavior needs of children.
基金Sponsored by Exploration of Sponge System Design in Wetland Parks Based on Rainwater and Flood Control:A Case Study of Southern Anhui Province(AH202112216126)Key Projects of Scientific Research(Natural Sciences)in Higher Education Institutions of Anhui Province(2022AH051861)+1 种基金Research Team Project of Anhui Xinhua University(kytd202202)Building Structure Key Laboratory Project of Anhui Province Ordinary Universities(KLBSZD202105).
文摘Based on the background that wetland resources in China are under threat and urgently need to be protected,a series of rainwater and flood problems caused by urban construction is analyzed comprehensively,and the design and planning methods of wetland parks in response to rainwater and flood disasters caused by floods and heavy rainfall are explored.Southern Anhui with complex and variable terrain and frequent rainfall and flood disasters is selected as the research area,with Xuanzhou District of Xuancheng City as the main research object.The relationship between municipal drainage of urban park and water conservancy drainage is investigated from different sample selection,design samples,and design flow rates.Based on literature review and model building methods,an urban storm flood model suitable for typical wetland parks in southern Anhui is constructed after processing the survey data using Arc GIS,SWMM(storm water management model).On this basis,a methodology and principles for designing a sponge system of wetland park based on rainwater and flood control are proposed,including technical measures such as rainwater collection,retention,and purification.This paper provides certain research results in design schemes,effect evaluations,ecological and social benefits,and useful suggestions and solutions for urban stormwater management and resilience development.
基金This work was supported by the Creative Groups of Natural Science Foundation of Hubei Province(Grant No.2021CFA030).Onyekwena Chikezie Chimere is an awardee for the ANSO Scholarship 2020-PhD.Ishrat Hameed Alvi is a recipient of the 2021 PhD ANSO Scholarship.
文摘Dredged marine soils(DMS)have poor engineering properties,which limit their usage in construction projects.This research examines the application of reactive magnesia(rMgO)containing supplementary cementitious materials(SCMs)to stabilize DMS under ambient and carbon dioxide(CO_(2))curing conditions.Several proprietary experimental tests were conducted to investigate the stabilized DMS.Furthermore,the carbonation-induced mineralogical,thermal,and microstructural properties change of the samples were explored.The findings show that the compressive strength of the stabilized DMS fulfilled the 7-d requirement(0.7-2.1 MPa)for pavement and building foundations.Replacing rMgO with SCMs such as biochar or ground granulated blast-furnace slag(GGBS)altered the engineering properties and particle packing of the stabilized soils,thus influencing their performances.Biochar increased the porosity of the samples,facilitating higher CO_(2) uptake and improved ductility,while GGBS decreased porosity and increased the dry density of the samples,resulting in higher strength.The addition of SCMs also enhanced the water retention capacity and modified the pH of the samples.Microstructural analysis revealed that the hydrated magnesium carbonates precipitated in the carbonated samples provided better cementation effects than brucite formed during rMgO hydration.Moreover,incorporating SCMs reduced the overall global warming potential and energy demand of the rMgO-based systems.The biochar mixes demonstrated lower toxicity and energy consumption.Ultimately,the rMgO and biochar blend can serve as an environmentally friendly additive for soft soil stabilization and permanent fixation of significant amounts of CO_(2) in soils through mineral carbonation,potentially reducing environmental pollution while meeting urbanization needs.
基金supported by the National Natural Science Foundation of China (21507130)the Chongqing Science and Technology Commission (cstc2016jcyjA 0070,cstc2014pt-gc20002,cstc2014yykfC 20003,cstckjcxljrc13)the Open Project Program of Chongqing Key Laboratory of Ca-talysis and Functional Organic Molecules from Chongqing Technology and Business University (1456029)~~
文摘To investigate how the physicochemical properties and NH3‐selective catalytic reduction(NH3‐SCR)performance of supported ceria‐based catalysts are influenced as a function of support type,a series of CeO2/SiO2,CeO2/γ‐Al2O3,CeO2/ZrO2,and CeO2/TiO2catalysts were prepared.The physicochemical properties were probed by means of X‐ray diffraction,Raman spectroscopy,Brunauer‐Emmett‐Teller surface area measurements,X‐ray photoelectron spectroscopy,H2‐temperature programmed reduction,and NH3‐temperature programmed desorption.Furthermore,the supported ceria‐based catalysts'catalytic performance and H2O+SO2tolerance were evaluated by the NH3‐SCR model reaction.The results indicate that out of the supported ceria‐based catalysts studied,the CeO2/γ‐Al2O3catalyst exhibits the highest catalytic activity as a result of having a high relative Ce3+/Ce4+ratio,optimum reduction behavior,and the largest total acid site concentration.Finally,the CeO2/γ‐Al2O3catalyst also presents excellent H2O+SO2tolerance during the NH3‐SCR process.