We investigated the structural behavior and bearing capacity of system scaffolds.The research showed that the critical load of a system scaffold structure without diagonal braces is similar to that of a door-shaped st...We investigated the structural behavior and bearing capacity of system scaffolds.The research showed that the critical load of a system scaffold structure without diagonal braces is similar to that of a door-shaped steel scaffold structure.Joint stiffness between vertical props in system scaffolds can be defined based on a comparison between analytical and experimental results.When the number of scaffold stories increases,the critical loads of system scaffolds decrease.Diagonal braces markedly enhance the critical load of system scaffolds.The coupling joint position between vertical props should be kept away from story-to-story joints to prevent a reduction in critical loads.The critical load of a system scaffold decreases as the quantity of extended vertical props at the bottom of the structure increases.A large Christmas tree set up by system scaffolds under various loads was used as an example for analysis and to check the design of system scaffolds.展开更多
Several potential failure modes generally exist in rock slopes because of the existence of massive structural planes in rock masses. A system reliability analyses method for rock slopes with multiple failure modes bas...Several potential failure modes generally exist in rock slopes because of the existence of massive structural planes in rock masses. A system reliability analyses method for rock slopes with multiple failure modes based on nonlinear Barton-Bandis failure criterion is proposed. The factors of safety associated with the sliding and overturning failure modes are derived, respectively. The validity of this method is verified through a planar rock slope with an inclined slope top and tension crack. Several sensitivity analyses are adopted to study the influences of structural-plane parameters, geometric parameters, anchoring parameters and fracture morphology on the rock slopes system reliability.展开更多
High density of buildings and population in urban areas increases urban temperature, generally known as the urban heat island. Raised temperature, especially in SUlIuner, alms city centers into unwelcome hot areas, wi...High density of buildings and population in urban areas increases urban temperature, generally known as the urban heat island. Raised temperature, especially in SUlIuner, alms city centers into unwelcome hot areas, with direct effects on electricity demand and energy consttrnption for cooling buildings and increases the production of carbon dioxide and other pollutants. Therefore, by considering that the energy consumption in the world has been faced with intense crisis, it becomes increasingly important to study the effects of urban heat island on energy constunption in order to improve people＇s environment and decrease energy use in cities. This paper, therefore, is focused on urbanization and population size factors to understand tile influence way of these factors on formation of UHI and energy consumption balance. To achieve this aim, this paper explores literally the conceptual framework of confliction between population and urban structure, which produce UHI intensity and affected energy consumption balance. It is then discussed how these two factors can be affected and give implication to the city, and then, focuses on whether actions should be taken for balancing adaptation and mitigation UHI effects. It will be concluded by making the recommendations for preventive action and provide quality of life.展开更多
The objective of this study is to incorporate a numerical model with GIS to simulate the movement, erosion and deposition of debris flow across the three dimensional complex terrain. In light of the importance of eros...The objective of this study is to incorporate a numerical model with GIS to simulate the movement, erosion and deposition of debris flow across the three dimensional complex terrain. In light of the importance of erosion and deposition processes during debris flow movement, no entrainment assumption is unreasonable. The numerical model considering these processes is used for simulating debris flow. Raster grid networks of a digital elevation model in GIS provide a uniform grid system to describe complex topography. As the raster grid can be used as the finite difference mesh, the numerical model is solved numerically using the Leap-frog finite difference method. Finally, the simulation results can be displayed by GIS easily and used to debris flow evaluation. To illustrate this approach, the proposed methodology is applied to the Yohutagawa debris flow that occurred on 2oth October 2010, in Amami- Oshima area, Japan. The simulation results that reproduced the movement, erosion and deposition are in good agreement with the field investigation. The effectiveness of the dam in this real-ease is also verified by this approach. Comparison with the results were simulated by other models, shows that the present coupled model is more rational and effective.展开更多
Raw water from the Yantian Reservoir in Southern China was used for this study. Several process parameters of biofiltration, temperature, media, empty bed contact time, ozone dosage and concentration of geosmin and MI...Raw water from the Yantian Reservoir in Southern China was used for this study. Several process parameters of biofiltration, temperature, media, empty bed contact time, ozone dosage and concentration of geosmin and MIB, were adopted in order to determine their effects. Experiments were conducted using the Taguchi method and 9 experiments were needed to obtain the best process parameter settings and parameter effects. The results of these experiments indicate the use of biological filtration as a method of geosmin and MIB removal, to be satisfactory. In addition, the results show that temperature impacts the removal rate of both geosmin and MIB. Useful insights into the effects of the filter media on such as, empty bed contact time, ozone dosage and concentration of geosmin and MIB were also obtained.展开更多
UV/H2O2/micro-aeration is a newly developed process based on UV/H2O2. Halogenated pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) photochemical degradation in aqueous solution was studied under various solution condi...UV/H2O2/micro-aeration is a newly developed process based on UV/H2O2. Halogenated pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) photochemical degradation in aqueous solution was studied under various solution conditions. The UV intensity,initial 2,4-D concentrations and solution temperature varied from 183.6 to 1048.7 μW·cm-2,from 59.2 to 300.0 μg·L-1 and from 15 to 30℃,respectively. The concentration of hydrogen peroxide (H2O2) and pH ranged from 0 to 50 mg·L-1 and 5 to 9,and different water quality solutions (tap water,distilled water and deionized water) were examined in this study. With initial concentration of about 100 μg·L-1,more than 95.6% of 2,4-D can be removed in 90 min at intensity of UV radiation of 843.9 μW·cm-2,H2O2 dosage of 20 mg·L-1,pH 7 and room temperature. The removal efficiency of 2,4-D by UV/H2O2/micro-aeration process is better than UV/H2O2 process. The photodecomposition of 2,4-D in aqueous solution follows pseudo-first-order kinetics. 2,4-D is greatly affected by UV irradation intensity,H2O2 dosage,initial 2,4-D concentration and water quality solutions,but it appears to be slightly influenced by pH and temperature. There is a linear relationship between rate constant k and UV intensity and initial H2O2 concentration,which indicates that higher removal capacity can be achieved by the improvement of these factors. Finally,a preliminary cost analysis reveals that UV/H2O2/micro-aeration process is more cost-effective than the UV/H2O2 process in the removal of 2,4-D from drinking water.展开更多
Debris flow is a rapid flow which could lead to severe flooding with catastrophic consequences such as damage to properties and loss of human lives.It is important to study the movement of debris flow.Since during a d...Debris flow is a rapid flow which could lead to severe flooding with catastrophic consequences such as damage to properties and loss of human lives.It is important to study the movement of debris flow.Since during a debris flow process,the erosion and deposition processes are important,the no entrainment assumption is not acceptable.In this study,first we considered the debris flow as equivalent fluid and adopted the depth-averaged govern equations to simulate the movements and evolution of river bed.Secondly,the set of partial differential equations was solved numerically by means of explicit staggered leap-frog scheme that is accurate in space and time.The grid of difference scheme was derived from GIS raster data.Then the simulation results can be displayed by GIS and easily used to form the hazard maps.Finally,the numerical model coupled with GIS is applied to simulate the debris flow occurred on Oct.20th,2010,in Amamioshima City,Japan.The simulation reproduces the movement,erosion and deposition.The results are shown to be consistent with the field investigation.展开更多
基金Project supported by the National Science Council,Taiwan(No. NSC 93-2211-E-224-002)the Service Center of Construction Tech-nology and Materials,National Yunlin University of Science and Technology,Taiwan(No.95-215)the Hong Kong Polytechnic University(Nos.PolyU 5115/07E and PolyU 5117/06E),Hong Kong,China
文摘We investigated the structural behavior and bearing capacity of system scaffolds.The research showed that the critical load of a system scaffold structure without diagonal braces is similar to that of a door-shaped steel scaffold structure.Joint stiffness between vertical props in system scaffolds can be defined based on a comparison between analytical and experimental results.When the number of scaffold stories increases,the critical loads of system scaffolds decrease.Diagonal braces markedly enhance the critical load of system scaffolds.The coupling joint position between vertical props should be kept away from story-to-story joints to prevent a reduction in critical loads.The critical load of a system scaffold decreases as the quantity of extended vertical props at the bottom of the structure increases.A large Christmas tree set up by system scaffolds under various loads was used as an example for analysis and to check the design of system scaffolds.
基金Project(51978666) supported by the National Natural Science Foundation of ChinaProject(2018-123-040) supported by the Guizhou Provincial Department of Transportation Foundation, ChinaProject(2019zzts009) supported by the Fundamental Research Funds for the Central Universities, China。
文摘Several potential failure modes generally exist in rock slopes because of the existence of massive structural planes in rock masses. A system reliability analyses method for rock slopes with multiple failure modes based on nonlinear Barton-Bandis failure criterion is proposed. The factors of safety associated with the sliding and overturning failure modes are derived, respectively. The validity of this method is verified through a planar rock slope with an inclined slope top and tension crack. Several sensitivity analyses are adopted to study the influences of structural-plane parameters, geometric parameters, anchoring parameters and fracture morphology on the rock slopes system reliability.
文摘High density of buildings and population in urban areas increases urban temperature, generally known as the urban heat island. Raised temperature, especially in SUlIuner, alms city centers into unwelcome hot areas, with direct effects on electricity demand and energy consttrnption for cooling buildings and increases the production of carbon dioxide and other pollutants. Therefore, by considering that the energy consumption in the world has been faced with intense crisis, it becomes increasingly important to study the effects of urban heat island on energy constunption in order to improve people＇s environment and decrease energy use in cities. This paper, therefore, is focused on urbanization and population size factors to understand tile influence way of these factors on formation of UHI and energy consumption balance. To achieve this aim, this paper explores literally the conceptual framework of confliction between population and urban structure, which produce UHI intensity and affected energy consumption balance. It is then discussed how these two factors can be affected and give implication to the city, and then, focuses on whether actions should be taken for balancing adaptation and mitigation UHI effects. It will be concluded by making the recommendations for preventive action and provide quality of life.
基金finanicial support from the Global Environment Research Fund of Japan(S-8)from Grants-in-Aid for Scientific Research(Scientific Research(B),22310113,G.Chen)from Japan Society for the Promotion of Science
文摘The objective of this study is to incorporate a numerical model with GIS to simulate the movement, erosion and deposition of debris flow across the three dimensional complex terrain. In light of the importance of erosion and deposition processes during debris flow movement, no entrainment assumption is unreasonable. The numerical model considering these processes is used for simulating debris flow. Raster grid networks of a digital elevation model in GIS provide a uniform grid system to describe complex topography. As the raster grid can be used as the finite difference mesh, the numerical model is solved numerically using the Leap-frog finite difference method. Finally, the simulation results can be displayed by GIS easily and used to debris flow evaluation. To illustrate this approach, the proposed methodology is applied to the Yohutagawa debris flow that occurred on 2oth October 2010, in Amami- Oshima area, Japan. The simulation results that reproduced the movement, erosion and deposition are in good agreement with the field investigation. The effectiveness of the dam in this real-ease is also verified by this approach. Comparison with the results were simulated by other models, shows that the present coupled model is more rational and effective.
文摘Raw water from the Yantian Reservoir in Southern China was used for this study. Several process parameters of biofiltration, temperature, media, empty bed contact time, ozone dosage and concentration of geosmin and MIB, were adopted in order to determine their effects. Experiments were conducted using the Taguchi method and 9 experiments were needed to obtain the best process parameter settings and parameter effects. The results of these experiments indicate the use of biological filtration as a method of geosmin and MIB removal, to be satisfactory. In addition, the results show that temperature impacts the removal rate of both geosmin and MIB. Useful insights into the effects of the filter media on such as, empty bed contact time, ozone dosage and concentration of geosmin and MIB were also obtained.
基金Supported by the National Major Science and Technology Project(Grant No.2008ZX07421-002)"11th Five-year Plan"Science and Technology Support Projects(Grant No.2006BAJ08B06)973 program(Grant No.2006CB403204)
文摘UV/H2O2/micro-aeration is a newly developed process based on UV/H2O2. Halogenated pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) photochemical degradation in aqueous solution was studied under various solution conditions. The UV intensity,initial 2,4-D concentrations and solution temperature varied from 183.6 to 1048.7 μW·cm-2,from 59.2 to 300.0 μg·L-1 and from 15 to 30℃,respectively. The concentration of hydrogen peroxide (H2O2) and pH ranged from 0 to 50 mg·L-1 and 5 to 9,and different water quality solutions (tap water,distilled water and deionized water) were examined in this study. With initial concentration of about 100 μg·L-1,more than 95.6% of 2,4-D can be removed in 90 min at intensity of UV radiation of 843.9 μW·cm-2,H2O2 dosage of 20 mg·L-1,pH 7 and room temperature. The removal efficiency of 2,4-D by UV/H2O2/micro-aeration process is better than UV/H2O2 process. The photodecomposition of 2,4-D in aqueous solution follows pseudo-first-order kinetics. 2,4-D is greatly affected by UV irradation intensity,H2O2 dosage,initial 2,4-D concentration and water quality solutions,but it appears to be slightly influenced by pH and temperature. There is a linear relationship between rate constant k and UV intensity and initial H2O2 concentration,which indicates that higher removal capacity can be achieved by the improvement of these factors. Finally,a preliminary cost analysis reveals that UV/H2O2/micro-aeration process is more cost-effective than the UV/H2O2 process in the removal of 2,4-D from drinking water.
基金This study was supported by the Global Environment Research Found of Japan(S-8)and Grants-in-Aid for Scientific Research(Scientific Research(B),22310113,G.Chen)from Japan Society for the Promotion of ScienceAnd the first author acknowledges the support of China Scholarship Council.These financial supports are gratefully acknowledged.
文摘Debris flow is a rapid flow which could lead to severe flooding with catastrophic consequences such as damage to properties and loss of human lives.It is important to study the movement of debris flow.Since during a debris flow process,the erosion and deposition processes are important,the no entrainment assumption is not acceptable.In this study,first we considered the debris flow as equivalent fluid and adopted the depth-averaged govern equations to simulate the movements and evolution of river bed.Secondly,the set of partial differential equations was solved numerically by means of explicit staggered leap-frog scheme that is accurate in space and time.The grid of difference scheme was derived from GIS raster data.Then the simulation results can be displayed by GIS and easily used to form the hazard maps.Finally,the numerical model coupled with GIS is applied to simulate the debris flow occurred on Oct.20th,2010,in Amamioshima City,Japan.The simulation reproduces the movement,erosion and deposition.The results are shown to be consistent with the field investigation.
