It is difficult to rescue people from outside, and emergency evacuation is still a main measure to decrease casualties in high-rise building fires. To improve evacuation efficiency, a valid and easily manipulated grou...It is difficult to rescue people from outside, and emergency evacuation is still a main measure to decrease casualties in high-rise building fires. To improve evacuation efficiency, a valid and easily manipulated grouping evacuation strategy is proposed. Occupants escape in groups according to the shortest evacuation route is determined by graph theory. In order to evaluate and find the optimal grouping, computational experiments are performed to design and simulate the evacuation processes. A case study shown the application in detail and quantitative research conclusions is obtained. The thoughts and approaches of this study can be used to guide actual high-rise building evacuation processes in future.展开更多
Decarbonization in operational residential buildings worldwide has become critical in achieving the carbon neutral target due to the growing household energy demand.To accelerate the pace of global carbon neutrality,t...Decarbonization in operational residential buildings worldwide has become critical in achieving the carbon neutral target due to the growing household energy demand.To accelerate the pace of global carbon neutrality,this study explores the operational carbon change in global residential buildings through the generalized Divisia index method and decoupling analysis,considering the decarbonization levels of residential buildings at different scales.The results show that(1)most of the samples showed a decrease in the total emissions from 2000 to 2019.Except for China and the United States(US),the carbon emissions in global residential building operations decreased by 7.95 million tons of carbon dioxide(MtCO_(2))per year over the study period.Emissions per gross domestic product(GDP)was the most positive driver causing the decarbonization of residential buildings,while GDP was the most negative driver.(2)Carbon intensity was essential to achieving a strong decoupling of economic development and carbon emissions.The US almost consistently presented strong decoupling,while China showed weak decoupling over the last two decades.(3)The pace of decarbonization in global residential building operations is gradually slowing down.From 2000 to 2019,decarbonization from residential buildings across 30 countries was 2094.3 MtCO_(2),with a decarbonization efficiency of 3.4%.Overall,this study addresses gaps in evaluating global decarbonization from operational residential buildings and provides a reference for evaluating building decarbonization by other emitters.展开更多
The development of diversified foods such as melons under the big food concept can reduce the pressure on staple food grain.Xinjiang has the advantages of building a new development pattern of dual circulation of dive...The development of diversified foods such as melons under the big food concept can reduce the pressure on staple food grain.Xinjiang has the advantages of building a new development pattern of dual circulation of diversified food industry and establishing a national diversified food safety and high-quality assurance center.The construction of an agricultural power needs the strategic support of an intellectual property power.This paper introduced and studied Xinjiang s melon industry and its agricultural intellectual property resources,analyzed the six main problems,including many idle land resources have not been developed into melon fields and the role of melons in diversified food supply systems not well played.Finally,it proposed to vigorously develop diversified food industries such as melons in Xinjiang and establish an eight-point strategy such as national diversified food safety and high-quality assurance center.展开更多
Tall buildings are being designed and built across a wide range of cities.A poorly designed tall building can tremendously increase the building’s appetite for energy.Therefore,this paper aims to determine the design...Tall buildings are being designed and built across a wide range of cities.A poorly designed tall building can tremendously increase the building’s appetite for energy.Therefore,this paper aims to determine the design strategies that help a high-rise office building to be more energy efficient.For this purpose,a comparative study on twelve case buildings in three climate groups(temperate,sub-tropical&tropical)was performed.The exterior envelope,building form and orientation,service core placement,plan layout,and special design elements like atria and sky gardens were the subject of investigation.effectiveness of different design strategies for reducing the cooling,heating,ventilation and electric lighting energy usage.Finally,lessons from these buildings’were defined for the three climates.Furthermore,a compari-son of building energy performance data with international benchmarks confirmed that in temperate and sub-tropical climates sustainable design strategies for high-rise buildings were performing well,as a result leading to lower energy consump-tion.However,for the tropics the design of high-rise buildings needs additional consideration.展开更多
Ⅰ. The way to the continuous development of China auto industry China auto industry began its step on the basis of equipment & technologies importation from the former USSR. From 1980s, for the sake of developing...Ⅰ. The way to the continuous development of China auto industry China auto industry began its step on the basis of equipment & technologies importation from the former USSR. From 1980s, for the sake of developing China car industry and展开更多
Laser powder bed fusion(LPBF)is an innovative method for manufacturing multimaterial components with high geometrical resolution.The LPBF-printing sequences of materials may be diverse in the actual design and applica...Laser powder bed fusion(LPBF)is an innovative method for manufacturing multimaterial components with high geometrical resolution.The LPBF-printing sequences of materials may be diverse in the actual design and application of multimaterial components.In this study,multimaterial copper(CuSn10)–steel(316 L)structures are printed using different building strategies(printing 316 L on CuSn10 and printing CuSn10 on 316 L)via LPBF,and the characteristics of two interfaces(the 316 L/CuSn10 or“L/C”and CuSn10/316 L or“C/L”interfaces)are investigated.Subsequently,the interfacial melting mode and formation mechanisms are discussed.At the L/C interface,the keyhole melting mode induced by the high volumetric energy density(EL/C=319.4 J/mm3)results in a large penetration depth in the pre-solidified layer and enhances laser energy absorption,thus promoting the extensive migration of materials and intense intermixing of elements to form a wide diffusion zone(∼400μm).At the C/L interface,the conduction mode induced by the low volumetric energy density(EC/L=74.1 J/mm3)results in a narrow diffusion zone(∼160μm).The interfacial defects observed are primarily cracks and pores.More cracks appeared at the C/L interface,which is attributable to the weak bonding strength of the narrow diffusion zone.This study provides guidance and reference for the design and manufacturing of multimaterial components via LPBF using different building strategies.展开更多
基金supported by Beijing University of Civil Engineering and Architecture Nature Science(ZF16078,X18067)
文摘It is difficult to rescue people from outside, and emergency evacuation is still a main measure to decrease casualties in high-rise building fires. To improve evacuation efficiency, a valid and easily manipulated grouping evacuation strategy is proposed. Occupants escape in groups according to the shortest evacuation route is determined by graph theory. In order to evaluate and find the optimal grouping, computational experiments are performed to design and simulate the evacuation processes. A case study shown the application in detail and quantitative research conclusions is obtained. The thoughts and approaches of this study can be used to guide actual high-rise building evacuation processes in future.
基金This manuscript has been authored by an author at Lawrence Berkeley National Laboratory under Contract No.DE-AC02-05CH11231 with the U.S.Department of Energy
文摘Decarbonization in operational residential buildings worldwide has become critical in achieving the carbon neutral target due to the growing household energy demand.To accelerate the pace of global carbon neutrality,this study explores the operational carbon change in global residential buildings through the generalized Divisia index method and decoupling analysis,considering the decarbonization levels of residential buildings at different scales.The results show that(1)most of the samples showed a decrease in the total emissions from 2000 to 2019.Except for China and the United States(US),the carbon emissions in global residential building operations decreased by 7.95 million tons of carbon dioxide(MtCO_(2))per year over the study period.Emissions per gross domestic product(GDP)was the most positive driver causing the decarbonization of residential buildings,while GDP was the most negative driver.(2)Carbon intensity was essential to achieving a strong decoupling of economic development and carbon emissions.The US almost consistently presented strong decoupling,while China showed weak decoupling over the last two decades.(3)The pace of decarbonization in global residential building operations is gradually slowing down.From 2000 to 2019,decarbonization from residential buildings across 30 countries was 2094.3 MtCO_(2),with a decarbonization efficiency of 3.4%.Overall,this study addresses gaps in evaluating global decarbonization from operational residential buildings and provides a reference for evaluating building decarbonization by other emitters.
基金Supported by Youth Project of National Social Science Fund of China(22CMZ015)。
文摘The development of diversified foods such as melons under the big food concept can reduce the pressure on staple food grain.Xinjiang has the advantages of building a new development pattern of dual circulation of diversified food industry and establishing a national diversified food safety and high-quality assurance center.The construction of an agricultural power needs the strategic support of an intellectual property power.This paper introduced and studied Xinjiang s melon industry and its agricultural intellectual property resources,analyzed the six main problems,including many idle land resources have not been developed into melon fields and the role of melons in diversified food supply systems not well played.Finally,it proposed to vigorously develop diversified food industries such as melons in Xinjiang and establish an eight-point strategy such as national diversified food safety and high-quality assurance center.
文摘Tall buildings are being designed and built across a wide range of cities.A poorly designed tall building can tremendously increase the building’s appetite for energy.Therefore,this paper aims to determine the design strategies that help a high-rise office building to be more energy efficient.For this purpose,a comparative study on twelve case buildings in three climate groups(temperate,sub-tropical&tropical)was performed.The exterior envelope,building form and orientation,service core placement,plan layout,and special design elements like atria and sky gardens were the subject of investigation.effectiveness of different design strategies for reducing the cooling,heating,ventilation and electric lighting energy usage.Finally,lessons from these buildings’were defined for the three climates.Furthermore,a compari-son of building energy performance data with international benchmarks confirmed that in temperate and sub-tropical climates sustainable design strategies for high-rise buildings were performing well,as a result leading to lower energy consump-tion.However,for the tropics the design of high-rise buildings needs additional consideration.
文摘Ⅰ. The way to the continuous development of China auto industry China auto industry began its step on the basis of equipment & technologies importation from the former USSR. From 1980s, for the sake of developing China car industry and
基金Guangdong Provincial Basic and Applied Basic Research Foundation of China(Grant Nos.2019B1515120094,2022B1515020064)National Natural Science Foundation of China(Grant No.52073105)Guangdong Provincial Key Field Research and Development Program of China(Grant No.2020B090922002).
文摘Laser powder bed fusion(LPBF)is an innovative method for manufacturing multimaterial components with high geometrical resolution.The LPBF-printing sequences of materials may be diverse in the actual design and application of multimaterial components.In this study,multimaterial copper(CuSn10)–steel(316 L)structures are printed using different building strategies(printing 316 L on CuSn10 and printing CuSn10 on 316 L)via LPBF,and the characteristics of two interfaces(the 316 L/CuSn10 or“L/C”and CuSn10/316 L or“C/L”interfaces)are investigated.Subsequently,the interfacial melting mode and formation mechanisms are discussed.At the L/C interface,the keyhole melting mode induced by the high volumetric energy density(EL/C=319.4 J/mm3)results in a large penetration depth in the pre-solidified layer and enhances laser energy absorption,thus promoting the extensive migration of materials and intense intermixing of elements to form a wide diffusion zone(∼400μm).At the C/L interface,the conduction mode induced by the low volumetric energy density(EC/L=74.1 J/mm3)results in a narrow diffusion zone(∼160μm).The interfacial defects observed are primarily cracks and pores.More cracks appeared at the C/L interface,which is attributable to the weak bonding strength of the narrow diffusion zone.This study provides guidance and reference for the design and manufacturing of multimaterial components via LPBF using different building strategies.