Internal thermal insulation composite system(ITICS)can be an important measure for the energy-saving retrofitting of buildings.However,ITICS may cause harmful effects on the hygrothermal performance of building envelo...Internal thermal insulation composite system(ITICS)can be an important measure for the energy-saving retrofitting of buildings.However,ITICS may cause harmful effects on the hygrothermal performance of building envelopes.This work investigated the influence of the materials’hygric properties on the hygrothermal perfor-mance of a typical ITICS in different climate conditions in China.Two base wall materials,the traditional concrete and a new type aerated concrete,were tested and compared for their hygric properties firstly.The influence of the hygroscopicity of exterior plasters,the permeability of insulation materials and the climate conditions were then analyzed with WUFI simulations.The hygrothermal performance was evaluated with consideration of the total water content(TWC)of the walls and the moisture flux strength,the relative humidity(RH)and the mould growth risk at the interface between the base wall and the insulation layer(B-I interface).The numerical analysis implies that the TWC of internal insulated walls depends mainly on the hygroscopicity of exterior plaster and the wind-driven rain intensity.The upper limits for the water absorption coefficient of exterior plasters used in Bei-jing,Shanghai and Fuzhou are 1e-9,1e-10,1e-10 m^(2)/s respectively.When such limits are guaranteed,a vapour tight system created by using insulation materials with a large vapour resistance factor or adding a vapour barrier can improve the hygrothermal performance of ITICS,especially for concrete walls in cold climate.展开更多
In this paper, the composition of HT-7 LHCD system along with its protection systems is introduced. It is very important for us to run the LHCD system safely and efficiently.
This paper addresses the composite nonlinear feedback（CNF） control for a class of singleinput single-output nonlinear systems with input saturation to track a time varying reference target with good transient perfor...This paper addresses the composite nonlinear feedback（CNF） control for a class of singleinput single-output nonlinear systems with input saturation to track a time varying reference target with good transient performance. The CNF control law consists of a tracking control law and a performance compensator. The tracking control law is designed to drive the output of the system to track the time varying reference target rapidly, while the performance compensator is used to reduce the overshoot caused by the tracking control law. The stability of the closed-loop system is established. The design procedure and the improvement of transient performance of the closed-loop system are illustrated with a numerical example and the controlled Van del Pol oscillator.展开更多
Electricity generated through coal-based Thermal Power Plants(TPPs)has played a pivotal role in shaping modern civiliza-tion,revolutionizing industries,and improving the quality of life for billions of people worldwid...Electricity generated through coal-based Thermal Power Plants(TPPs)has played a pivotal role in shaping modern civiliza-tion,revolutionizing industries,and improving the quality of life for billions of people worldwide.These TPPs contribute to about 37%-40%of the global energy requirements.Energy production,in turn,has a direct impact on the economy of any country.Apart from this boon to humankind,these TPPs combusting coal as their primary fuel also have specific environmen-tal impacts,the major ones being water,air,and soil pollution due to unscientific disposal of high-quantity fly ash produced yearly.If we can put this ash to good use,it may assist us in mitigating the pollution caused by it.Although there are many conventional uses of fly ash,such as a pozzolanic material in the cement industry,more pathways need to be discovered to balance the high generation quantities with consumption.Therefore,a detailed description of its use in potential geoliner applications is presented in this article.A geoliner or a landfill liner acts as a virtually impenetrable layer to mitigate the leachate penetration into the underneath subsoil and groundwater,thus preventing contamination.There are presently some studies that support the use of only fly ash in such applications.Nevertheless,the properties of the geoliners using it are not so good to significantly mitigate environmental degradation owing to its high permeability and low densification tendency.The bentonite conventionally used has limited deposits and is mined intensively for its use as a natural sealant.Their depos-its must also be conserved,and an alternative material that may serve similar application benefits,like bentonite,must be selected.The desired aim can be fulfilled if we blend this combustion residue with other suitable materials(such as kaolinite clay)with low permeability.Thus,the article focuses on the possibilities of blending fly ash with different clays for geoliner construction to improve the individual properties of fly ash.This will contribute to developing a scope for future scientific research in deploying these blends in natural membrane materials for various industries.Different types of geoliners that are designed to contain the disposed-off waste are also explained in detail.Additionally,a glimpse of the global fly ash market is put forward to depict its importance for various industries in this technologically advancing world.This article profoundly observes an overall environmental management aspect regarding waste utilization.展开更多
基金This research was funded by National Key R&D Program of China(2017YFC0702800),which is gratefully acknowledged.
文摘Internal thermal insulation composite system(ITICS)can be an important measure for the energy-saving retrofitting of buildings.However,ITICS may cause harmful effects on the hygrothermal performance of building envelopes.This work investigated the influence of the materials’hygric properties on the hygrothermal perfor-mance of a typical ITICS in different climate conditions in China.Two base wall materials,the traditional concrete and a new type aerated concrete,were tested and compared for their hygric properties firstly.The influence of the hygroscopicity of exterior plasters,the permeability of insulation materials and the climate conditions were then analyzed with WUFI simulations.The hygrothermal performance was evaluated with consideration of the total water content(TWC)of the walls and the moisture flux strength,the relative humidity(RH)and the mould growth risk at the interface between the base wall and the insulation layer(B-I interface).The numerical analysis implies that the TWC of internal insulated walls depends mainly on the hygroscopicity of exterior plaster and the wind-driven rain intensity.The upper limits for the water absorption coefficient of exterior plasters used in Bei-jing,Shanghai and Fuzhou are 1e-9,1e-10,1e-10 m^(2)/s respectively.When such limits are guaranteed,a vapour tight system created by using insulation materials with a large vapour resistance factor or adding a vapour barrier can improve the hygrothermal performance of ITICS,especially for concrete walls in cold climate.
文摘In this paper, the composition of HT-7 LHCD system along with its protection systems is introduced. It is very important for us to run the LHCD system safely and efficiently.
基金supported by the National Nature Science Foundation of China under Grant Nos.61374035 and 61733017
文摘This paper addresses the composite nonlinear feedback（CNF） control for a class of singleinput single-output nonlinear systems with input saturation to track a time varying reference target with good transient performance. The CNF control law consists of a tracking control law and a performance compensator. The tracking control law is designed to drive the output of the system to track the time varying reference target rapidly, while the performance compensator is used to reduce the overshoot caused by the tracking control law. The stability of the closed-loop system is established. The design procedure and the improvement of transient performance of the closed-loop system are illustrated with a numerical example and the controlled Van del Pol oscillator.
文摘Electricity generated through coal-based Thermal Power Plants(TPPs)has played a pivotal role in shaping modern civiliza-tion,revolutionizing industries,and improving the quality of life for billions of people worldwide.These TPPs contribute to about 37%-40%of the global energy requirements.Energy production,in turn,has a direct impact on the economy of any country.Apart from this boon to humankind,these TPPs combusting coal as their primary fuel also have specific environmen-tal impacts,the major ones being water,air,and soil pollution due to unscientific disposal of high-quantity fly ash produced yearly.If we can put this ash to good use,it may assist us in mitigating the pollution caused by it.Although there are many conventional uses of fly ash,such as a pozzolanic material in the cement industry,more pathways need to be discovered to balance the high generation quantities with consumption.Therefore,a detailed description of its use in potential geoliner applications is presented in this article.A geoliner or a landfill liner acts as a virtually impenetrable layer to mitigate the leachate penetration into the underneath subsoil and groundwater,thus preventing contamination.There are presently some studies that support the use of only fly ash in such applications.Nevertheless,the properties of the geoliners using it are not so good to significantly mitigate environmental degradation owing to its high permeability and low densification tendency.The bentonite conventionally used has limited deposits and is mined intensively for its use as a natural sealant.Their depos-its must also be conserved,and an alternative material that may serve similar application benefits,like bentonite,must be selected.The desired aim can be fulfilled if we blend this combustion residue with other suitable materials(such as kaolinite clay)with low permeability.Thus,the article focuses on the possibilities of blending fly ash with different clays for geoliner construction to improve the individual properties of fly ash.This will contribute to developing a scope for future scientific research in deploying these blends in natural membrane materials for various industries.Different types of geoliners that are designed to contain the disposed-off waste are also explained in detail.Additionally,a glimpse of the global fly ash market is put forward to depict its importance for various industries in this technologically advancing world.This article profoundly observes an overall environmental management aspect regarding waste utilization.
