The impact sensitivity assessment of spacecraft is to obtain the probability of spacecraft encountering the OD/M(orbital debris or meteoroid),which is a prerequisite for survivability assessment of on-orbit spacecraft...The impact sensitivity assessment of spacecraft is to obtain the probability of spacecraft encountering the OD/M(orbital debris or meteoroid),which is a prerequisite for survivability assessment of on-orbit spacecraft.An impact sensitivity assessment method of spacecraft based on virtual exterior wall was proposed to improve the computational efficiency.This method eliminates determination of the outermost surface elements of the spacecraft before generating the debris rays,which are assumed to originate from a non-concave virtual wall that completely wraps the spacecraft.The Dist Mesh method was adopted for the generating of the virtual wall to ensure its mesh quality.The influences of the sizes,mesh densities,shapes of the virtual wall on the efficiency and accuracy were considered to obtain the best combination of the size and mesh density of the wall and spacecraft.The results of this method were compared with those of S3DE(Survivability of Spacecraft in Space Debris Environment),BUMPER,MDPANTO,ESABASE2/Debris to verify the feasibility of the method.The PCHIP(Piecewise Cubic Hermite Interpolating Polynomial)was used to fit the size vs.flux relationship of the space debris to acquire the impact probability of OD/M with arbitrary size on the spacecraft.展开更多
The energy efficiency design of the exterior wall in the buildings of the hot summer and cold winter zone of China should consider the heat prevention in summer and the heat insulation in winter. The self-insulation o...The energy efficiency design of the exterior wall in the buildings of the hot summer and cold winter zone of China should consider the heat prevention in summer and the heat insulation in winter. The self-insulation of the exterior?wall is a more feasible design to satisfy the energy efficiency of buildings in the?zone. However, the systematic research is urgently needed for the self-insulation of the exterior wall in the hot summer and cold winter zone of China. The paper tested the thermal performance of the common non-clay materials such as shale sintered hollow brick, sand autoclaved aerated concrete block, etc. by means of indoor experiments. The energy efficiency effect of the common materials was verified using dynamic calculation soft PKPM and several constitutions of exterior wall with different main bricks and insulation materials on the heat bridge were simulated, too. Besides, the tests of the thermal performance of exterior wall in real constructions were carried out to testify the practical effect of the recommended constitutions of exterior wall with different main bricks and insulation materials on the heat bridge. The conclusions are: the physical and thermal properties of the six non-clay wall material are better than the clay porous brick;the thermal performance of the non-clay brick can be improved obviously through the rational arrangement of the holes;shale sintered hollow brick after increasing the holes and rationalizing the hole arrangement and sand autoclaved aerated concrete block are recommended for buildings in the hot summer and cold winter area of China. The dynamic calculation results show that the thermal performances?of the non-clay materials are all satisfied with the energy efficiency;The heat transfer coefficient of the exterior wall with composition?③,?in which?the main wall was sand autoclaved aerated concrete block and the material on the heat bridge was sand autoclaved aerated concrete plate, is the smallest among the three recommended compositions.展开更多
In this paper, the suitability and construction technology of self-insulation walls were studied under the specific climatic conditions and regional resources of Hanzhong and Ankang in the hot summer and cold winter z...In this paper, the suitability and construction technology of self-insulation walls were studied under the specific climatic conditions and regional resources of Hanzhong and Ankang in the hot summer and cold winter zone of Southern Shaanxi. Through the calculation of heat transfer coefficient and thermal inertia index, combined with the specifications of the shale hollow brick and aerated concrete block of Hanzhong and Ankang in southern Shaanxi, the thermal performance and suitable thickness of the external wall using self-insulation materials that meet the Design Standard for Energy Efficiency of Residential Buildings(DBJ61-65-2011) in Shaanxi Province were obtained. The results showed that the self-insulation wall had technical suitability in the hot summer and cold winter zone. The research results provide not only a theoretical basis for the external wall insulation design of urban residential buildings in the hot summer and cold winter zone of southern Shaanxi, but also a reference for designers to carry out energy-saving design of external walls of residential buildings in other similar climate zones.展开更多
This research will develop a set of assessment techniques and proce-dures for exterior wall deterioration detection.The proposed method is mainly based on equipped with high-resolution photographic equipment for unman...This research will develop a set of assessment techniques and proce-dures for exterior wall deterioration detection.The proposed method is mainly based on equipped with high-resolution photographic equipment for unmanned aerial vehicle(UAV).To overcome the problems of visual inspection difficulties due to diferent angles and height,the proposed method provides a safer and more efficient detection way to get the buildings'exterior status.After using the pro-posed method to analyze the images taken from UAV,the size of the damaged area can be evaluated more accurately,and the accuracy rate of visual assessment will be significantly improved.The results of the proposed method can reduce the accidents caused by the inspection process in the critical environment and the costs incured by the temporary facilities without sacrificing the quality of the inspection results.Then,the research will implement the existing visual assessment method because of the characteristics of rapid detection,however,the assessment results will be different from different inspectors due to subjectivity.Thus,the research will present an improved visual inspection method by using UAV and Forward Looking Infred Thermal technology (FLIR).The result will be presented by Condition Index(CI-Level)instead to improve the subjectivity of the personnel.展开更多
With the continuous development and progress of China's social economy,the construction speed of our construction industry is also accelerating.Compared with the traditional cast-in-place reinforced concrete and m...With the continuous development and progress of China's social economy,the construction speed of our construction industry is also accelerating.Compared with the traditional cast-in-place reinforced concrete and masonry building,it has been unable to meet the requirements of the construction industry and the development of the times.Because the prefabricated building has the advantages of fast speed,water saving,land saving,noise reduction,material saving and energy saving in installation.Compared with traditional buildings,the prefabricated building is more energy efficient and practical.Therefore,the new type of precast assembly architecture is constantly highlighted and has become the mainstream of the development of the future construction industry.However,the technology started late in China,and the immature technology and imperfect supporting standards led to slow progress and even stagnation in China's construction industry.Through the analysis of the present situation and problems of the waterproof and sealing of the prefabricated building exterior walls,the suggestions for the healthy development of the construction industry in China are put forward in time.展开更多
文摘The impact sensitivity assessment of spacecraft is to obtain the probability of spacecraft encountering the OD/M(orbital debris or meteoroid),which is a prerequisite for survivability assessment of on-orbit spacecraft.An impact sensitivity assessment method of spacecraft based on virtual exterior wall was proposed to improve the computational efficiency.This method eliminates determination of the outermost surface elements of the spacecraft before generating the debris rays,which are assumed to originate from a non-concave virtual wall that completely wraps the spacecraft.The Dist Mesh method was adopted for the generating of the virtual wall to ensure its mesh quality.The influences of the sizes,mesh densities,shapes of the virtual wall on the efficiency and accuracy were considered to obtain the best combination of the size and mesh density of the wall and spacecraft.The results of this method were compared with those of S3DE(Survivability of Spacecraft in Space Debris Environment),BUMPER,MDPANTO,ESABASE2/Debris to verify the feasibility of the method.The PCHIP(Piecewise Cubic Hermite Interpolating Polynomial)was used to fit the size vs.flux relationship of the space debris to acquire the impact probability of OD/M with arbitrary size on the spacecraft.
文摘The energy efficiency design of the exterior wall in the buildings of the hot summer and cold winter zone of China should consider the heat prevention in summer and the heat insulation in winter. The self-insulation of the exterior?wall is a more feasible design to satisfy the energy efficiency of buildings in the?zone. However, the systematic research is urgently needed for the self-insulation of the exterior wall in the hot summer and cold winter zone of China. The paper tested the thermal performance of the common non-clay materials such as shale sintered hollow brick, sand autoclaved aerated concrete block, etc. by means of indoor experiments. The energy efficiency effect of the common materials was verified using dynamic calculation soft PKPM and several constitutions of exterior wall with different main bricks and insulation materials on the heat bridge were simulated, too. Besides, the tests of the thermal performance of exterior wall in real constructions were carried out to testify the practical effect of the recommended constitutions of exterior wall with different main bricks and insulation materials on the heat bridge. The conclusions are: the physical and thermal properties of the six non-clay wall material are better than the clay porous brick;the thermal performance of the non-clay brick can be improved obviously through the rational arrangement of the holes;shale sintered hollow brick after increasing the holes and rationalizing the hole arrangement and sand autoclaved aerated concrete block are recommended for buildings in the hot summer and cold winter area of China. The dynamic calculation results show that the thermal performances?of the non-clay materials are all satisfied with the energy efficiency;The heat transfer coefficient of the exterior wall with composition?③,?in which?the main wall was sand autoclaved aerated concrete block and the material on the heat bridge was sand autoclaved aerated concrete plate, is the smallest among the three recommended compositions.
文摘In this paper, the suitability and construction technology of self-insulation walls were studied under the specific climatic conditions and regional resources of Hanzhong and Ankang in the hot summer and cold winter zone of Southern Shaanxi. Through the calculation of heat transfer coefficient and thermal inertia index, combined with the specifications of the shale hollow brick and aerated concrete block of Hanzhong and Ankang in southern Shaanxi, the thermal performance and suitable thickness of the external wall using self-insulation materials that meet the Design Standard for Energy Efficiency of Residential Buildings(DBJ61-65-2011) in Shaanxi Province were obtained. The results showed that the self-insulation wall had technical suitability in the hot summer and cold winter zone. The research results provide not only a theoretical basis for the external wall insulation design of urban residential buildings in the hot summer and cold winter zone of southern Shaanxi, but also a reference for designers to carry out energy-saving design of external walls of residential buildings in other similar climate zones.
文摘This research will develop a set of assessment techniques and proce-dures for exterior wall deterioration detection.The proposed method is mainly based on equipped with high-resolution photographic equipment for unmanned aerial vehicle(UAV).To overcome the problems of visual inspection difficulties due to diferent angles and height,the proposed method provides a safer and more efficient detection way to get the buildings'exterior status.After using the pro-posed method to analyze the images taken from UAV,the size of the damaged area can be evaluated more accurately,and the accuracy rate of visual assessment will be significantly improved.The results of the proposed method can reduce the accidents caused by the inspection process in the critical environment and the costs incured by the temporary facilities without sacrificing the quality of the inspection results.Then,the research will implement the existing visual assessment method because of the characteristics of rapid detection,however,the assessment results will be different from different inspectors due to subjectivity.Thus,the research will present an improved visual inspection method by using UAV and Forward Looking Infred Thermal technology (FLIR).The result will be presented by Condition Index(CI-Level)instead to improve the subjectivity of the personnel.
文摘With the continuous development and progress of China's social economy,the construction speed of our construction industry is also accelerating.Compared with the traditional cast-in-place reinforced concrete and masonry building,it has been unable to meet the requirements of the construction industry and the development of the times.Because the prefabricated building has the advantages of fast speed,water saving,land saving,noise reduction,material saving and energy saving in installation.Compared with traditional buildings,the prefabricated building is more energy efficient and practical.Therefore,the new type of precast assembly architecture is constantly highlighted and has become the mainstream of the development of the future construction industry.However,the technology started late in China,and the immature technology and imperfect supporting standards led to slow progress and even stagnation in China's construction industry.Through the analysis of the present situation and problems of the waterproof and sealing of the prefabricated building exterior walls,the suggestions for the healthy development of the construction industry in China are put forward in time.