With a view to accelerating the construction and development of the free trade zones and the foreign trade business of enterprises within the said zones, and making entering or leaving the zones convenient for those e...With a view to accelerating the construction and development of the free trade zones and the foreign trade business of enterprises within the said zones, and making entering or leaving the zones convenient for those enterprises; the Customs shall in accordance with the newly promulgated regulations as stipulated in Supervising Measures of the Customs in Free Trade Zones require that consigness, consignors or their agents register for the record their car.展开更多
In China,numerous cities are expanding into sloping land,yet the quantitative distribution patterns of urban built-up land density along the slope gradient remain unclear,limiting the understanding of sloping land urb...In China,numerous cities are expanding into sloping land,yet the quantitative distribution patterns of urban built-up land density along the slope gradient remain unclear,limiting the understanding of sloping land urbanization.In this paper,a simple negative exponential function was presented to verify its applicability in 19 typical sloping urban areas in China.The function fits well for all case urban areas(R^(2)≥0.951,p<0.001).The parameters of this function clearly describe two fundamental attributes:initial value a and decline rate b.Between 2000 and 2020,a tends to increase,while b tends to decrease in all urban areas,confirming the hypothesis of mutual promotion between flatland densification and sloping land expansion.Multiple regression analysis indicates that the built-up land density and the ruggedness of background land can explain 70.7%of a,while the average slope ratio of built-up land to background land,the built-up land density and the built-up land area can explain 82.1%of b.This work provides a quantitative investigative tool for distribution of urban built-up land density along slope gradient,aiding in the study of the globally increasing phenomenon of sloping land urbanization from a new perspective.展开更多
China had implemented the national strategies for Major Function-oriented Zones （MFOZs） to realize the goal of national sustainable development since 2010. This study analyzed and compared spatio-temporal characteri...China had implemented the national strategies for Major Function-oriented Zones （MFOZs） to realize the goal of national sustainable development since 2010. This study analyzed and compared spatio-temporal characteristics and differences in built-up area for China＇s MFOZs using a China＇ s Land Use Database （CLUD） derived from high-resolution remotely sensed images in the periods of 2000-2010 and 2010-2013. To sum up： （1） The percentage of built-up area in each of the MFOZs was significantly different, revealing the gradient feature of national land development based on the distribution of the main functions. （2） Annual growth in built-up area in optimal development zones （ODZs） decreased signifi- cantly during 2010-2013 compared with the period 2000-2010, while annual growth in built-up area in key development zones （KDZs）, agricultural production zones （APZs） and key ecological function zones （KEFZs） increased significantly. （3） In ODZs, the average annual increase in built-up area in the Yangtze River Delta region was significantly higher than in other regions; the average area increase and rate of increase of built-up area in KDZs was faster in the western region than in other regions; average annual area growth of built-up area in APZs in the northeast, central and western regions was twice as high as the previous decade on average; the annual rate of change and increase in the dynamic degree of built-up area were most notable in KEFZs in the central region. （4） The spatial pattern and charac- teristics of built-up area expansions in the period 2010-2013 reflected the gradient feature of the plan for MFOZs. But the rate of increase locally in built-up area in ODZs, APZs and KEFZs is fast, so the effective measures must be adopted in the implementation of national and regional policies. The conclusions indicated these methods and results were meaningful for future regulation strategies in optimizing national land development in China.展开更多
An experimental program was initiated to investigate the seismic performance of built-up laced steel brace members. Quasi-static testing of twelve typical steel built-up laced member （BLM） specimens was conducted. T...An experimental program was initiated to investigate the seismic performance of built-up laced steel brace members. Quasi-static testing of twelve typical steel built-up laced member （BLM） specimens was conducted. These were designed to span a range of parameters typically encountered for such members based on findings from a survey of commonly used shapes and details that have been historically used. The specimens were subdivided into groups of three different cross-sectional shapes, namely built-up I-shape section, and built-up box shapes buckling about the x or the y axis. Within each group, global and local buckling slenderness ratios had either kl/r values of 60 or 120, and b/t ratios of 8 or 16. The specific inelastic cyclic behavior germane to each specimen, and general observations on overall member hysteretic behavior as a function of the considered parameters, are reported. A companion paper （Lee and Bruneau 2008） investigates this observed response against predictions from analytical models, and behavior in the perspective of system performance.展开更多
The test results described in Part 1 of this paper （Lee and Bruneau, 2008） on twelve steel built-up laced members （BLMs） subjected to quasi-static loading are analyzed to provide better knowledge on their seismic ...The test results described in Part 1 of this paper （Lee and Bruneau, 2008） on twelve steel built-up laced members （BLMs） subjected to quasi-static loading are analyzed to provide better knowledge on their seismic behavior. Strength capacity of the BLM specimens is correlated with the strength predicted by the AISC LRFD Specifications. Assessments of hysteretic properties such as ductility capacity, energy dissipation capacity, and strength degradation after buckling of the specimen are performed. The compressive strength of BLMs is found to be relatively well predicted by the AISC LRFD Specifications. BLMs with smaller kl/r were ductile but failed to reach the target ductility of 3.0 before starting to fracture, while those with larger kl/r could meet the ductility demand in most cases. The normalized energy dissipation ratio, EC/ET and the normalized compressive strength degradation, Cr″/Cr of BLMs typically decrease as normalized displacements δ/δb,exp increase, and the ratios for specimens with larger kl/r dropped more rapidly than for specimens with smaller kl/r; similar trends were observed for the monolithic braces. The BLMs with a smaller slenderness ratio, kl/r, and width-to-thickness ratio, b/t, experienced a larger number of inelastic cycles than those with larger ratios.展开更多
Non-linear finite element models accounting for large displacements have been used to investigate the behavior of steel built-up shear links that had previously been tested using large-scale experiments. The links wer...Non-linear finite element models accounting for large displacements have been used to investigate the behavior of steel built-up shear links that had previously been tested using large-scale experiments. The links were designed using steel grades with yield points ranging from high to low strengths. The objectives of the numerical analyses were to further investigate the non-linear behavior and to correlate the numerical results with experimental observations. Elasto-plastic as well as cyclic stress-strain material properties were incorporated to study the influence of material behavior on the overall shear link response. Non-linear monotonie analyses of the shear links incorporating the cyclic stress-strain steel properties resulted in similar trends in the response as the backbone curves recorded from the physical experiments. The numerical models of built-up shear links utilizing structural grade steels closely correlated to the experimentally recorded shear strength. Models utilizing low yield point steels overestimated the shear strength, which was caused by the characteristics of cyclic behavior of those steels. The detailed numerical models also allowed for investigation of the plastic strain demands on the different components of the link. It was shown that finite element models combined with appropriate stress-strain relationship may be used with confidence to check the design of shear links of different steel grades and sectional geometries.展开更多
On July 24, 2013, a low-E coated glass project of Xianyang Co., Ltd. of Taiwanglass Group with a daily capacity of 1.2 thousand tons was started to be built, meanwhile a float glass production line was put into produc...On July 24, 2013, a low-E coated glass project of Xianyang Co., Ltd. of Taiwanglass Group with a daily capacity of 1.2 thousand tons was started to be built, meanwhile a float glass production line was put into production. The float glass line with CNY 1.5 billion of investment was built in July, 2008. Total investment of phase I of the Iow-E coated glass project was CNY one billion. The annual production value of the proiect can reach CNY one billion after completion of the whole project.展开更多
Designing “liveable” cities as climate change effects are felt all over the world has become a priority to city authorities as ways are sought to reduce rising temperatures in urban areas. Urban Heat Island (UHI) ef...Designing “liveable” cities as climate change effects are felt all over the world has become a priority to city authorities as ways are sought to reduce rising temperatures in urban areas. Urban Heat Island (UHI) effect occurs when there is a difference in temperature between rural and urban areas. In urban areas, impervious surfaces absorb heat during the day and release it at night, making urban areas warmer compared to rural areas which cool faster at night. This Urban Heat Island effect is particularly noticeable at night. Noticeable negative effects of Urban Heat Islands include health problems, air pollution, water shortages and higher energy requirements. The main objective of this research paper was to analyze the spatial and temporal relationship between Land Surface Temperature (LST) and Normalized Density Vegetation Index (NDVI) and Built-Up Density Index (BDI) in Upper-Hill, Nairobi Kenya. The changes in land cover would be represented by analyzing the two indices NDVI and BDI. Results showed the greatest increase in temperature within Upper-Hill of up to 3.96°C between the years 2015 and 2017. There was also an increase in impervious surfaces as indicated by NDVI and BDI within Upper-Hill and its surroundings. The linear regression results showed a negative correlation between LST and NDVI and a positive correlation with BDI, which is a better predictor of Land Surface Temperature than NDVI. Data sets were analyzed from Landsat imagery for the periods 1987, 2002, 2015 and 2017 to determine changes in land surface temperatures over a 30 year period and it’s relation to land cover changes using indices. Visual comparisons between Temperature differences between the years revealed that temperatures decreased around the urban areas. Minimum and maximum temperatures showed an increase of 1.6°C and 3.65°C respectively between 1987 and 2017. The comparisons between LST, NDVI and BDI show the results to be significantly different. The use of NDVI and BDI to study changes in land cover due to urbanization, reduces the time taken to manually classify moderate resolution satellite imagery.展开更多
Places of large potentials of sustainable energy production and places of large energy consumption are often very different and separated by large distances across the globe. This paper first discusses potentials of s...Places of large potentials of sustainable energy production and places of large energy consumption are often very different and separated by large distances across the globe. This paper first discusses potentials of solar technology in terms of global availability using PV （photovoltaic） technology and actual energy production. Solar energy is widely under-used and one way to reduce this is to improve production in low-energy places with high demand： large cities. According to this option, about 40% of the electricity consumption in the built environment could be produced by solar PV systems and energy storage systems. This paper discusses conditions in the built environment and functional and design qualities enabling an increased diffusion of the technologies In a comparative analysis of PV technologies, the criteria taken into account encompass efficiency of the type of solar cell and commercial availability. Special attention is paid to the design features of different PV systems, like flexibility, colour and transparency that might help in their utilization as integrated in building material and ornaments in modem architecture. The same procedure is followed for electricity storage devices. The preliminary conclusion is that at present the freedom of design is largest for a combination of crystalline silicon PV cells and Li-ion batteries.展开更多
Urban river riparian spaces and their natural systems are valuable to urban dwellers;but are increasingly affected and ruined by human activities and in particular, urbanization processes. In this research, land sat a...Urban river riparian spaces and their natural systems are valuable to urban dwellers;but are increasingly affected and ruined by human activities and in particular, urbanization processes. In this research, land sat and sentinel satellite imagery apt for change detection in vegetation cover, both landsat and sentinel imagery, covering the period between 1970 and 2021 in epochs of 1973, 1984, 1993, 2003, 2015 and 2021 years were used to establish the correlation between vegetation cover and built-up area along River Riara river reserve. The images were analysed to extract the built-up areas along the river reserve, including the buildings, and the rate of human settlements, which influenced vegetation cover. Normalized Difference Built-Up Index (NDBI) and Normalized Difference Vegetation Index (NDVI) were computed using the Short-Wave Infrared (SWIR) and the Near Infra-Red (NIR) bands to show the rate of change over the years. Results indicate NDVI values were high, compared to NDBI values along river Riara in the years 1973 and 1993 implying that there was more vegetation cover then. However, in the year 2021, the NDVI indicated the highest value at 0.88, with the complementary NDBI indicating the highest NDBI value at 0.47. This represents a significant increase in built-up areas since 2015 more than in previous epochs. Either, there was a significant increase in NDBI values, from 0.24 in 1993 to 0.47 in 2021. More so, the R-squared value at 0.80 informed 80% relationship between NDBI and NDVI values indicating a negative correlation.展开更多
N-11-azaartemisinins potentially active against Plasmodium falciparum are designed by combining molecular electrostatic potential (MEP), ligand-receptor interaction, and models built with supervised machine learning m...N-11-azaartemisinins potentially active against Plasmodium falciparum are designed by combining molecular electrostatic potential (MEP), ligand-receptor interaction, and models built with supervised machine learning methods (PCA, HCA, KNN, SIMCA, and SDA). The optimization of molecular structures was performed using the B3LYP/6-31G* approach. MEP maps and ligand-receptor interactions were used to investigate key structural features required for biological activities and likely interactions between N-11-azaartemisinins and heme, respectively. The supervised machine learning methods allowed the separation of the investigated compounds into two classes: cha and cla, with the properties ε<sub>LUMO+1</sub> (one level above lowest unoccupied molecular orbital energy), d(C<sub>6</sub>-C<sub>5</sub>) (distance between C<sub>6</sub> and C<sub>5</sub> atoms in ligands), and TSA (total surface area) responsible for the classification. The insights extracted from the investigation developed and the chemical intuition enabled the design of sixteen new N-11-azaartemisinins (prediction set), moreover, models built with supervised machine learning methods were applied to this prediction set. The result of this application showed twelve new promising N-11-azaartemisinins for synthesis and biological evaluation.展开更多
This study examined the influence of the built environment surrounding rail stations on rail transit ridership and its spatiotemporal variations,aiming to enhance rail transit operational efficiency and inform station...This study examined the influence of the built environment surrounding rail stations on rail transit ridership and its spatiotemporal variations,aiming to enhance rail transit operational efficiency and inform station planning and development.Data from 159 metro stations in Nanjing,collected over a 14-d period,were analyzed to identify changes in weekday and weekend ridership patterns.The analysis included explanatory variables grouped into three categories:urban spatial variables,socioeconomic vari-ables,and transit service variables.A geographically and temporally weighted regression(GTWR)model was developed,and its performance was compared with that of ordinary least squares(OLS)and geographically weighted regression(GWR)models.The results demonstrated that the GTWR model outperformed others in analyzing the relationship between rail transit ridership and the built environment.In addition,the coefficients of explanatory variables showed significant variation across spatiotemporal dimensions,revealing distinct patterns.Notably,the influence of commuter flows led to more pronounced temporal heterogeneity in the coefficients observed on weekdays.These findings offer valuable insights for optimizing urban public transportation systems and advancing integrated urban rail development.展开更多
A low-carbon lifestyle presents new opportunities for sustainable urban development.While previous studies have verified the impact of the built environment and socioeconomic status(SES)on low-carbon lifestyles,they h...A low-carbon lifestyle presents new opportunities for sustainable urban development.While previous studies have verified the impact of the built environment and socioeconomic status(SES)on low-carbon lifestyles,they have primarily focused on direct effects.At present,there is still a lack of analysis on the interaction effects on low-carbon lifestyles,and limited attention has been given to the peer effect in low-carbon lifestyles,especially in the context of residential differentiation.Therefore,we take Zhengzhou city as the case area and first calculate the low-carbon lifestyle of 1485 families from three dimensions:low-carbon action(A),low-carbon interest(I)and low-carbon opinion(O).We then analyze the direct and interactive impacts of the built environment and SES on low-carbon lifestyles and explore the peer effect.Our findings indicate that families with higher SES have higher levels of low-carbon interest and low-carbon opinion,but relatively low levels of low-carbon action.This suggests an interest-action bias in the low-carbon lifestyles of high-SES families.POI density,road network density and accessibility positively affect low-carbon lifestyles—that is,residents living in areas with well-developed infrastructure and convenient transportation tend to be green in their daily behavior.The peer effect influences low-carbon action,interest,and opinion by 54.6%,34.9%,and 16%,respectively,indicating that the peer effect is most evident in low-carbon action.That is,the peer effect is more obvious in low-carbon action.In addition,the built environment affects the low-carbon lifestyles of different SES groups.Land-use mix positively increases low-carbon action and low-carbon interest among high-SES groups but reduces low-carbon opinion.Road network density positively affects the low-carbon action of high-SES groups and the low-carbon interest and low-carbon opinion of low-SES groups.This study explores low-carbon lifestyles from a situational perspective,providing a practical basis for policies aimed at accelerating a transition to sustainable living.展开更多
As globalization accelerates,microbial contamination in the built environment poses a major public health challenge.Especially since Corona Virus Disease 2019(COVID-19),microbial sterilization technology has become a ...As globalization accelerates,microbial contamination in the built environment poses a major public health challenge.Especially since Corona Virus Disease 2019(COVID-19),microbial sterilization technology has become a crucial research area for indoor air pollution control in order to create a hygienic and safe built environment.Based on this,the study reviews sterilization technologies in the built environment,focusing on the principles,efficiency and applicability,revealing advantages and limitations,and summarizing current research advances.Despite the efficacy of single sterilization technologies in specific environments,the corresponding side effects still exist.Thus,this review highlights the efficiency of hybrid sterilization technologies,providing an in-depth understanding of the practical application in the built environment.Also,it presents an outlook on the future direction of sterilization technology,including the development of new methods that are more efficient,energy-saving,and targeted to better address microbial contamination in the complex and changing built environment.Overall,this study provides a clear guide for selecting technologies to handle microbial contamination in different building environments in the future,as well as a scientific basis for developing more effective air quality control strategies.展开更多
Newly built tunnels often encounter a series of defects within the first few years of operation.If not promptly addressed and reinforced,these defects threaten the tunnel's durability and stability and bring sever...Newly built tunnels often encounter a series of defects within the first few years of operation.If not promptly addressed and reinforced,these defects threaten the tunnel's durability and stability and bring severe challenges to its safe operation.This study aims to explore reinforcement techniques for addressing defects in newly built tunnels.The research begins with an analysis of common defects found in newly built tunnels,followed by a case study of the Jinfeng Tunnel in Chongqing,examining the post-construction defects.The actual reinforcement strategies and methods employed for the tunnel are then discussed.Finally,based on the research findings,this study provides insights and references for tunnel operation and construction units in China,aiming to enhance the overall quality of tunnel engineering in the country,align with sustainable development goals,and promote further improvements at a macro level.展开更多
The effects of the built environment factors on urban vitality have attracted wide attention in the urban planning fields in recent years,but few studies have considered the variables’relative importance and their no...The effects of the built environment factors on urban vitality have attracted wide attention in the urban planning fields in recent years,but few studies have considered the variables’relative importance and their nonlinear effects on urban vitality.Taking a Chinese metropolis—Hangzhou as a case study,this study applied the gradient boosting decision tree(GBDT)model to explore the nonlinear effects of the 5D factors of the urban built environment on urban social vitality and economic vitality and the importance of variables.The results show that the GBDT model has better goodness of fit than the traditional ordinary least squares(OLS)regression in the urban vitality models.The urban built environment plays an important role in affecting urban vitality,while built environment designs witness the most important effect.Specifically,the density of shopping facilities,medical facilities,and road networks are the most important factors affecting urban social vitality,while road network density,destination accessibility,and population density play the most important roles in affecting urban economic vitality.Finally,the urban built environment factors have nonlinear threshold effects on both urban economic and social vitality in Hangzhou,with differing nonlinear response patterns observed between social and economic dimensions.展开更多
Urban vitality is one of the key indicators of sustainable urban development and an important factor for shrinking cities to achieve internal optimization.The relationship between the built environment and urban vital...Urban vitality is one of the key indicators of sustainable urban development and an important factor for shrinking cities to achieve internal optimization.The relationship between the built environment and urban vitality has been extensively discussed.However,the moderating effect of housing vacancy on the built environment’s effect on urban vitality in shrinking cities has not been explored in detail.This paper selected Yichun District in Yichun City of Heilongjiang Province,a typical shrinking city in Northeast China,as the study area,focusing on the effect of the built environment on urban vitality in shrinking cities based on residential and commercial electricity consumption data for 2013 and 2018.Moreover,this study also explored the moderating mechanisms of residential and commercial housing vacancies on the built environment’s effect on urban vitality.The results demonstrate that the spatial pattern of urban vitality in the Yichun District is‘high in the center and low in the periphery’.Population density,building age,road density,and catering facilities are recognized as the main built environment factors affecting the vitality of shrinking cities.Residential and commercial housing vacancies have a significant moderating effect on the built environment’s effect on urban vitality.Residential housing vacancies enhance the positive effect of road density and the negative effect of greening rate.In addition,commercial housing vacancies suppress the positive effect of building density and enhance the positive effect of accessibility to urban service facilities.The study indicates that built environment factors exhibit heterogeneous effects on vitality in the context of urban shrinkage,as moderated by housing vacancies.Targeted regulation of built environment factors is of practical significance in realizing the internal development and vitality enhancement of shrinking cities.展开更多
文摘With a view to accelerating the construction and development of the free trade zones and the foreign trade business of enterprises within the said zones, and making entering or leaving the zones convenient for those enterprises; the Customs shall in accordance with the newly promulgated regulations as stipulated in Supervising Measures of the Customs in Free Trade Zones require that consigness, consignors or their agents register for the record their car.
基金supported by the project of the National Natural Science Foundation of China entitled“Distribution and change characteristics of construction land on slope gradient in mountainous cities of southern China”(No.41961039).
文摘In China,numerous cities are expanding into sloping land,yet the quantitative distribution patterns of urban built-up land density along the slope gradient remain unclear,limiting the understanding of sloping land urbanization.In this paper,a simple negative exponential function was presented to verify its applicability in 19 typical sloping urban areas in China.The function fits well for all case urban areas(R^(2)≥0.951,p<0.001).The parameters of this function clearly describe two fundamental attributes:initial value a and decline rate b.Between 2000 and 2020,a tends to increase,while b tends to decrease in all urban areas,confirming the hypothesis of mutual promotion between flatland densification and sloping land expansion.Multiple regression analysis indicates that the built-up land density and the ruggedness of background land can explain 70.7%of a,while the average slope ratio of built-up land to background land,the built-up land density and the built-up land area can explain 82.1%of b.This work provides a quantitative investigative tool for distribution of urban built-up land density along slope gradient,aiding in the study of the globally increasing phenomenon of sloping land urbanization from a new perspective.
基金Key Project of National Natural Science Foundation of China, No.41371409 National Key Technology R＆D Program, No.2013BAC03B00
文摘China had implemented the national strategies for Major Function-oriented Zones （MFOZs） to realize the goal of national sustainable development since 2010. This study analyzed and compared spatio-temporal characteristics and differences in built-up area for China＇s MFOZs using a China＇ s Land Use Database （CLUD） derived from high-resolution remotely sensed images in the periods of 2000-2010 and 2010-2013. To sum up： （1） The percentage of built-up area in each of the MFOZs was significantly different, revealing the gradient feature of national land development based on the distribution of the main functions. （2） Annual growth in built-up area in optimal development zones （ODZs） decreased signifi- cantly during 2010-2013 compared with the period 2000-2010, while annual growth in built-up area in key development zones （KDZs）, agricultural production zones （APZs） and key ecological function zones （KEFZs） increased significantly. （3） In ODZs, the average annual increase in built-up area in the Yangtze River Delta region was significantly higher than in other regions; the average area increase and rate of increase of built-up area in KDZs was faster in the western region than in other regions; average annual area growth of built-up area in APZs in the northeast, central and western regions was twice as high as the previous decade on average; the annual rate of change and increase in the dynamic degree of built-up area were most notable in KEFZs in the central region. （4） The spatial pattern and charac- teristics of built-up area expansions in the period 2010-2013 reflected the gradient feature of the plan for MFOZs. But the rate of increase locally in built-up area in ODZs, APZs and KEFZs is fast, so the effective measures must be adopted in the implementation of national and regional policies. The conclusions indicated these methods and results were meaningful for future regulation strategies in optimizing national land development in China.
基金Federal Highway Administration Under Grant No. DTFH61-98-C-00094
文摘An experimental program was initiated to investigate the seismic performance of built-up laced steel brace members. Quasi-static testing of twelve typical steel built-up laced member （BLM） specimens was conducted. These were designed to span a range of parameters typically encountered for such members based on findings from a survey of commonly used shapes and details that have been historically used. The specimens were subdivided into groups of three different cross-sectional shapes, namely built-up I-shape section, and built-up box shapes buckling about the x or the y axis. Within each group, global and local buckling slenderness ratios had either kl/r values of 60 or 120, and b/t ratios of 8 or 16. The specific inelastic cyclic behavior germane to each specimen, and general observations on overall member hysteretic behavior as a function of the considered parameters, are reported. A companion paper （Lee and Bruneau 2008） investigates this observed response against predictions from analytical models, and behavior in the perspective of system performance.
基金Federal Highway Administration Under Grant No.DTFH61-98-C-00094
文摘The test results described in Part 1 of this paper （Lee and Bruneau, 2008） on twelve steel built-up laced members （BLMs） subjected to quasi-static loading are analyzed to provide better knowledge on their seismic behavior. Strength capacity of the BLM specimens is correlated with the strength predicted by the AISC LRFD Specifications. Assessments of hysteretic properties such as ductility capacity, energy dissipation capacity, and strength degradation after buckling of the specimen are performed. The compressive strength of BLMs is found to be relatively well predicted by the AISC LRFD Specifications. BLMs with smaller kl/r were ductile but failed to reach the target ductility of 3.0 before starting to fracture, while those with larger kl/r could meet the ductility demand in most cases. The normalized energy dissipation ratio, EC/ET and the normalized compressive strength degradation, Cr″/Cr of BLMs typically decrease as normalized displacements δ/δb,exp increase, and the ratios for specimens with larger kl/r dropped more rapidly than for specimens with smaller kl/r; similar trends were observed for the monolithic braces. The BLMs with a smaller slenderness ratio, kl/r, and width-to-thickness ratio, b/t, experienced a larger number of inelastic cycles than those with larger ratios.
基金the Federal Highway Administration through the Highway Project at the Multidisciplinary Center for Earthquake Engineering Researchthe toll bridge retrofit program of the California Department of Transportation through the University of California,San Diego
文摘Non-linear finite element models accounting for large displacements have been used to investigate the behavior of steel built-up shear links that had previously been tested using large-scale experiments. The links were designed using steel grades with yield points ranging from high to low strengths. The objectives of the numerical analyses were to further investigate the non-linear behavior and to correlate the numerical results with experimental observations. Elasto-plastic as well as cyclic stress-strain material properties were incorporated to study the influence of material behavior on the overall shear link response. Non-linear monotonie analyses of the shear links incorporating the cyclic stress-strain steel properties resulted in similar trends in the response as the backbone curves recorded from the physical experiments. The numerical models of built-up shear links utilizing structural grade steels closely correlated to the experimentally recorded shear strength. Models utilizing low yield point steels overestimated the shear strength, which was caused by the characteristics of cyclic behavior of those steels. The detailed numerical models also allowed for investigation of the plastic strain demands on the different components of the link. It was shown that finite element models combined with appropriate stress-strain relationship may be used with confidence to check the design of shear links of different steel grades and sectional geometries.
文摘On July 24, 2013, a low-E coated glass project of Xianyang Co., Ltd. of Taiwanglass Group with a daily capacity of 1.2 thousand tons was started to be built, meanwhile a float glass production line was put into production. The float glass line with CNY 1.5 billion of investment was built in July, 2008. Total investment of phase I of the Iow-E coated glass project was CNY one billion. The annual production value of the proiect can reach CNY one billion after completion of the whole project.
文摘Designing “liveable” cities as climate change effects are felt all over the world has become a priority to city authorities as ways are sought to reduce rising temperatures in urban areas. Urban Heat Island (UHI) effect occurs when there is a difference in temperature between rural and urban areas. In urban areas, impervious surfaces absorb heat during the day and release it at night, making urban areas warmer compared to rural areas which cool faster at night. This Urban Heat Island effect is particularly noticeable at night. Noticeable negative effects of Urban Heat Islands include health problems, air pollution, water shortages and higher energy requirements. The main objective of this research paper was to analyze the spatial and temporal relationship between Land Surface Temperature (LST) and Normalized Density Vegetation Index (NDVI) and Built-Up Density Index (BDI) in Upper-Hill, Nairobi Kenya. The changes in land cover would be represented by analyzing the two indices NDVI and BDI. Results showed the greatest increase in temperature within Upper-Hill of up to 3.96°C between the years 2015 and 2017. There was also an increase in impervious surfaces as indicated by NDVI and BDI within Upper-Hill and its surroundings. The linear regression results showed a negative correlation between LST and NDVI and a positive correlation with BDI, which is a better predictor of Land Surface Temperature than NDVI. Data sets were analyzed from Landsat imagery for the periods 1987, 2002, 2015 and 2017 to determine changes in land surface temperatures over a 30 year period and it’s relation to land cover changes using indices. Visual comparisons between Temperature differences between the years revealed that temperatures decreased around the urban areas. Minimum and maximum temperatures showed an increase of 1.6°C and 3.65°C respectively between 1987 and 2017. The comparisons between LST, NDVI and BDI show the results to be significantly different. The use of NDVI and BDI to study changes in land cover due to urbanization, reduces the time taken to manually classify moderate resolution satellite imagery.
文摘Places of large potentials of sustainable energy production and places of large energy consumption are often very different and separated by large distances across the globe. This paper first discusses potentials of solar technology in terms of global availability using PV （photovoltaic） technology and actual energy production. Solar energy is widely under-used and one way to reduce this is to improve production in low-energy places with high demand： large cities. According to this option, about 40% of the electricity consumption in the built environment could be produced by solar PV systems and energy storage systems. This paper discusses conditions in the built environment and functional and design qualities enabling an increased diffusion of the technologies In a comparative analysis of PV technologies, the criteria taken into account encompass efficiency of the type of solar cell and commercial availability. Special attention is paid to the design features of different PV systems, like flexibility, colour and transparency that might help in their utilization as integrated in building material and ornaments in modem architecture. The same procedure is followed for electricity storage devices. The preliminary conclusion is that at present the freedom of design is largest for a combination of crystalline silicon PV cells and Li-ion batteries.
文摘Urban river riparian spaces and their natural systems are valuable to urban dwellers;but are increasingly affected and ruined by human activities and in particular, urbanization processes. In this research, land sat and sentinel satellite imagery apt for change detection in vegetation cover, both landsat and sentinel imagery, covering the period between 1970 and 2021 in epochs of 1973, 1984, 1993, 2003, 2015 and 2021 years were used to establish the correlation between vegetation cover and built-up area along River Riara river reserve. The images were analysed to extract the built-up areas along the river reserve, including the buildings, and the rate of human settlements, which influenced vegetation cover. Normalized Difference Built-Up Index (NDBI) and Normalized Difference Vegetation Index (NDVI) were computed using the Short-Wave Infrared (SWIR) and the Near Infra-Red (NIR) bands to show the rate of change over the years. Results indicate NDVI values were high, compared to NDBI values along river Riara in the years 1973 and 1993 implying that there was more vegetation cover then. However, in the year 2021, the NDVI indicated the highest value at 0.88, with the complementary NDBI indicating the highest NDBI value at 0.47. This represents a significant increase in built-up areas since 2015 more than in previous epochs. Either, there was a significant increase in NDBI values, from 0.24 in 1993 to 0.47 in 2021. More so, the R-squared value at 0.80 informed 80% relationship between NDBI and NDVI values indicating a negative correlation.
文摘N-11-azaartemisinins potentially active against Plasmodium falciparum are designed by combining molecular electrostatic potential (MEP), ligand-receptor interaction, and models built with supervised machine learning methods (PCA, HCA, KNN, SIMCA, and SDA). The optimization of molecular structures was performed using the B3LYP/6-31G* approach. MEP maps and ligand-receptor interactions were used to investigate key structural features required for biological activities and likely interactions between N-11-azaartemisinins and heme, respectively. The supervised machine learning methods allowed the separation of the investigated compounds into two classes: cha and cla, with the properties ε<sub>LUMO+1</sub> (one level above lowest unoccupied molecular orbital energy), d(C<sub>6</sub>-C<sub>5</sub>) (distance between C<sub>6</sub> and C<sub>5</sub> atoms in ligands), and TSA (total surface area) responsible for the classification. The insights extracted from the investigation developed and the chemical intuition enabled the design of sixteen new N-11-azaartemisinins (prediction set), moreover, models built with supervised machine learning methods were applied to this prediction set. The result of this application showed twelve new promising N-11-azaartemisinins for synthesis and biological evaluation.
基金The National Key Research and Development Program of China(No.2022YFC3800201).
文摘This study examined the influence of the built environment surrounding rail stations on rail transit ridership and its spatiotemporal variations,aiming to enhance rail transit operational efficiency and inform station planning and development.Data from 159 metro stations in Nanjing,collected over a 14-d period,were analyzed to identify changes in weekday and weekend ridership patterns.The analysis included explanatory variables grouped into three categories:urban spatial variables,socioeconomic vari-ables,and transit service variables.A geographically and temporally weighted regression(GTWR)model was developed,and its performance was compared with that of ordinary least squares(OLS)and geographically weighted regression(GWR)models.The results demonstrated that the GTWR model outperformed others in analyzing the relationship between rail transit ridership and the built environment.In addition,the coefficients of explanatory variables showed significant variation across spatiotemporal dimensions,revealing distinct patterns.Notably,the influence of commuter flows led to more pronounced temporal heterogeneity in the coefficients observed on weekdays.These findings offer valuable insights for optimizing urban public transportation systems and advancing integrated urban rail development.
基金National Natural Science Foundation of China,No.42171295,No.42401380Outstanding Youth Science Fund of Henan Province,No.242300421144+1 种基金The Postgraduate Cultivating Innovation and Quality Improvement Action Plan of Henan University,No.SYLYC2022013Henan Science and Technology Innovation Talent Project,No.24HASTIT050。
文摘A low-carbon lifestyle presents new opportunities for sustainable urban development.While previous studies have verified the impact of the built environment and socioeconomic status(SES)on low-carbon lifestyles,they have primarily focused on direct effects.At present,there is still a lack of analysis on the interaction effects on low-carbon lifestyles,and limited attention has been given to the peer effect in low-carbon lifestyles,especially in the context of residential differentiation.Therefore,we take Zhengzhou city as the case area and first calculate the low-carbon lifestyle of 1485 families from three dimensions:low-carbon action(A),low-carbon interest(I)and low-carbon opinion(O).We then analyze the direct and interactive impacts of the built environment and SES on low-carbon lifestyles and explore the peer effect.Our findings indicate that families with higher SES have higher levels of low-carbon interest and low-carbon opinion,but relatively low levels of low-carbon action.This suggests an interest-action bias in the low-carbon lifestyles of high-SES families.POI density,road network density and accessibility positively affect low-carbon lifestyles—that is,residents living in areas with well-developed infrastructure and convenient transportation tend to be green in their daily behavior.The peer effect influences low-carbon action,interest,and opinion by 54.6%,34.9%,and 16%,respectively,indicating that the peer effect is most evident in low-carbon action.That is,the peer effect is more obvious in low-carbon action.In addition,the built environment affects the low-carbon lifestyles of different SES groups.Land-use mix positively increases low-carbon action and low-carbon interest among high-SES groups but reduces low-carbon opinion.Road network density positively affects the low-carbon action of high-SES groups and the low-carbon interest and low-carbon opinion of low-SES groups.This study explores low-carbon lifestyles from a situational perspective,providing a practical basis for policies aimed at accelerating a transition to sustainable living.
文摘As globalization accelerates,microbial contamination in the built environment poses a major public health challenge.Especially since Corona Virus Disease 2019(COVID-19),microbial sterilization technology has become a crucial research area for indoor air pollution control in order to create a hygienic and safe built environment.Based on this,the study reviews sterilization technologies in the built environment,focusing on the principles,efficiency and applicability,revealing advantages and limitations,and summarizing current research advances.Despite the efficacy of single sterilization technologies in specific environments,the corresponding side effects still exist.Thus,this review highlights the efficiency of hybrid sterilization technologies,providing an in-depth understanding of the practical application in the built environment.Also,it presents an outlook on the future direction of sterilization technology,including the development of new methods that are more efficient,energy-saving,and targeted to better address microbial contamination in the complex and changing built environment.Overall,this study provides a clear guide for selecting technologies to handle microbial contamination in different building environments in the future,as well as a scientific basis for developing more effective air quality control strategies.
文摘Newly built tunnels often encounter a series of defects within the first few years of operation.If not promptly addressed and reinforced,these defects threaten the tunnel's durability and stability and bring severe challenges to its safe operation.This study aims to explore reinforcement techniques for addressing defects in newly built tunnels.The research begins with an analysis of common defects found in newly built tunnels,followed by a case study of the Jinfeng Tunnel in Chongqing,examining the post-construction defects.The actual reinforcement strategies and methods employed for the tunnel are then discussed.Finally,based on the research findings,this study provides insights and references for tunnel operation and construction units in China,aiming to enhance the overall quality of tunnel engineering in the country,align with sustainable development goals,and promote further improvements at a macro level.
基金National Social Science Foundation of China,No.20FJLB025National Natural Science Foundation of China,No.42471207,No.42471203Zhejiang Province Philosophy and Social Science Planning,Zhijiang Youth Special Project,24ZJQN118Y。
文摘The effects of the built environment factors on urban vitality have attracted wide attention in the urban planning fields in recent years,but few studies have considered the variables’relative importance and their nonlinear effects on urban vitality.Taking a Chinese metropolis—Hangzhou as a case study,this study applied the gradient boosting decision tree(GBDT)model to explore the nonlinear effects of the 5D factors of the urban built environment on urban social vitality and economic vitality and the importance of variables.The results show that the GBDT model has better goodness of fit than the traditional ordinary least squares(OLS)regression in the urban vitality models.The urban built environment plays an important role in affecting urban vitality,while built environment designs witness the most important effect.Specifically,the density of shopping facilities,medical facilities,and road networks are the most important factors affecting urban social vitality,while road network density,destination accessibility,and population density play the most important roles in affecting urban economic vitality.Finally,the urban built environment factors have nonlinear threshold effects on both urban economic and social vitality in Hangzhou,with differing nonlinear response patterns observed between social and economic dimensions.
基金Under the auspices of the National Natural Science Foundation of China(No.42171191,41771172,42201211,42401249)Science and Technology Development Plan Project of Jilin Province,China(No.20220508025RC)Young Scientist Group Project of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(No.2022QNXZ02)。
文摘Urban vitality is one of the key indicators of sustainable urban development and an important factor for shrinking cities to achieve internal optimization.The relationship between the built environment and urban vitality has been extensively discussed.However,the moderating effect of housing vacancy on the built environment’s effect on urban vitality in shrinking cities has not been explored in detail.This paper selected Yichun District in Yichun City of Heilongjiang Province,a typical shrinking city in Northeast China,as the study area,focusing on the effect of the built environment on urban vitality in shrinking cities based on residential and commercial electricity consumption data for 2013 and 2018.Moreover,this study also explored the moderating mechanisms of residential and commercial housing vacancies on the built environment’s effect on urban vitality.The results demonstrate that the spatial pattern of urban vitality in the Yichun District is‘high in the center and low in the periphery’.Population density,building age,road density,and catering facilities are recognized as the main built environment factors affecting the vitality of shrinking cities.Residential and commercial housing vacancies have a significant moderating effect on the built environment’s effect on urban vitality.Residential housing vacancies enhance the positive effect of road density and the negative effect of greening rate.In addition,commercial housing vacancies suppress the positive effect of building density and enhance the positive effect of accessibility to urban service facilities.The study indicates that built environment factors exhibit heterogeneous effects on vitality in the context of urban shrinkage,as moderated by housing vacancies.Targeted regulation of built environment factors is of practical significance in realizing the internal development and vitality enhancement of shrinking cities.
