Murals in Mogao Grottoes consist of three parts:support layer,earthen plasters and paint layer.The earthen plasters play a key role in the preservation of murals.It is a mixture of Dengban soil,sand,and plant fiber.Tw...Murals in Mogao Grottoes consist of three parts:support layer,earthen plasters and paint layer.The earthen plasters play a key role in the preservation of murals.It is a mixture of Dengban soil,sand,and plant fiber.Two different natural fibers,hemp fiber and cotton fiber,were reinforced to earthen plasters in the same percentage to evaluate the influence on hygrothermal performance.The two types of earthen plasters were studied:one containing hemp fiber in the fine plaster(HFP)and the other containing cotton fiber in the fine plaster(CFP).Specific heat capacity,dry thermal conductivity,water vapor permeability,and sorption isotherms were investigated.The results showed that the difference between two natural fibers has much more impact on the hygric properties(water vapor permeability and sorption isotherms)of earthen plasters than on their thermal performance(specific heat capacity and dry thermal conductivity).The CFP with higher density has higher thermal conductivity than the HFP with lower density.But no significant differences of specific heat capacity were observed.Compared with HFP,CFP used in murals can reduce the rate of water transfer and prevent salt from transferring water to the mural surface.The overall findings highlight that all these features of CFP are beneficial to the long-term preservation of murals.The study of the earthen plasters in Mogao Grottoes is of general significance,and the measured properties can be used to obtain coupled heat and moisture analysis of the earthen plasters and to dissect the degradation mechanism of murals.展开更多
It is well known that the passive strategies applying in traditional buildings respond satisfactory to climatic requirements and succeed to provide maximum indoor comfort with minimum energy consumption.From this poin...It is well known that the passive strategies applying in traditional buildings respond satisfactory to climatic requirements and succeed to provide maximum indoor comfort with minimum energy consumption.From this point of view,it is interesting to quantitatively assess the effectiveness of the vernacular strategies to improve the environmental performance of the building's envelope under desert climate conditions.The research tries to address this issue and was undertaken in southern Algeria where a very hot and arid climate prevails.The effect of some selected passive cooling strategies on enhancing the building's envelope climate performance was examined.These strategies are inspired from the local vernacular architecture,and they are expected to provide satisfactory indoor thermal comfort for users and to reduce the energy cooling demand from residential buildings.Applying field and computational investigations,two existing residential buildings were tested:a typical residential unit and a contemporary vernacular(neo-vernacular)building.In the latter,climate responsive strategies inspired from vernacular architecture were applied.A comparison based on site measurements was carried out on the two selected buildings which differ from their envelope design properties and components.展开更多
In China,over 1.43×10^(7)tons of dewatered sewage sludge,with 80%water content,were generated from wastewater treatment plants in 2007.About 60%of the COD removed during the wastewater treatment process becomes c...In China,over 1.43×10^(7)tons of dewatered sewage sludge,with 80%water content,were generated from wastewater treatment plants in 2007.About 60%of the COD removed during the wastewater treatment process becomes concentrated as sludge.Traditional disposal methods used by municipal solid waste treatment facilities,such as landfills,composting,or incineration,are unsuitable for sludge disposal because of its high water content.Disposal of sludge has therefore become a major focus of current environmental protection policies.The present status of sludge treatment and disposal methodology is introduced in this paper.Decreasing the energy consumption of sludge dewatering from 80%to 50%has been a key issue for safe and economic sludge disposal.In an analysis of sludge water distribution,thermal drying and hydrothermal conditioning processes are compared.Although thermal drying could result in an almost dry sludge,the energy consumption needed for this process is extremely high.In comparison,hydrothermal technology could achieve dewatered sewage sludge with a 50%–60%water content,which is suitable for composting,incineration,or landfill.The energy consumption of hydrothermal technology is lower than that required for thermal drying.展开更多
基金This project was supported by the National Natural Science Foundation of China(Projects No.51378412)China State Administration of Cultural Heritage(Project No.20110308).
文摘Murals in Mogao Grottoes consist of three parts:support layer,earthen plasters and paint layer.The earthen plasters play a key role in the preservation of murals.It is a mixture of Dengban soil,sand,and plant fiber.Two different natural fibers,hemp fiber and cotton fiber,were reinforced to earthen plasters in the same percentage to evaluate the influence on hygrothermal performance.The two types of earthen plasters were studied:one containing hemp fiber in the fine plaster(HFP)and the other containing cotton fiber in the fine plaster(CFP).Specific heat capacity,dry thermal conductivity,water vapor permeability,and sorption isotherms were investigated.The results showed that the difference between two natural fibers has much more impact on the hygric properties(water vapor permeability and sorption isotherms)of earthen plasters than on their thermal performance(specific heat capacity and dry thermal conductivity).The CFP with higher density has higher thermal conductivity than the HFP with lower density.But no significant differences of specific heat capacity were observed.Compared with HFP,CFP used in murals can reduce the rate of water transfer and prevent salt from transferring water to the mural surface.The overall findings highlight that all these features of CFP are beneficial to the long-term preservation of murals.The study of the earthen plasters in Mogao Grottoes is of general significance,and the measured properties can be used to obtain coupled heat and moisture analysis of the earthen plasters and to dissect the degradation mechanism of murals.
文摘It is well known that the passive strategies applying in traditional buildings respond satisfactory to climatic requirements and succeed to provide maximum indoor comfort with minimum energy consumption.From this point of view,it is interesting to quantitatively assess the effectiveness of the vernacular strategies to improve the environmental performance of the building's envelope under desert climate conditions.The research tries to address this issue and was undertaken in southern Algeria where a very hot and arid climate prevails.The effect of some selected passive cooling strategies on enhancing the building's envelope climate performance was examined.These strategies are inspired from the local vernacular architecture,and they are expected to provide satisfactory indoor thermal comfort for users and to reduce the energy cooling demand from residential buildings.Applying field and computational investigations,two existing residential buildings were tested:a typical residential unit and a contemporary vernacular(neo-vernacular)building.In the latter,climate responsive strategies inspired from vernacular architecture were applied.A comparison based on site measurements was carried out on the two selected buildings which differ from their envelope design properties and components.
基金the National High Technology Research and Development Program of China(Grant No.2006AA06Z384).
文摘In China,over 1.43×10^(7)tons of dewatered sewage sludge,with 80%water content,were generated from wastewater treatment plants in 2007.About 60%of the COD removed during the wastewater treatment process becomes concentrated as sludge.Traditional disposal methods used by municipal solid waste treatment facilities,such as landfills,composting,or incineration,are unsuitable for sludge disposal because of its high water content.Disposal of sludge has therefore become a major focus of current environmental protection policies.The present status of sludge treatment and disposal methodology is introduced in this paper.Decreasing the energy consumption of sludge dewatering from 80%to 50%has been a key issue for safe and economic sludge disposal.In an analysis of sludge water distribution,thermal drying and hydrothermal conditioning processes are compared.Although thermal drying could result in an almost dry sludge,the energy consumption needed for this process is extremely high.In comparison,hydrothermal technology could achieve dewatered sewage sludge with a 50%–60%water content,which is suitable for composting,incineration,or landfill.The energy consumption of hydrothermal technology is lower than that required for thermal drying.
