Increased urbanisation,economic growth,and long-term climate variability have made both the UK and China more susceptible to urban and river flooding,putting people and property at increased risk.This paper presents a...Increased urbanisation,economic growth,and long-term climate variability have made both the UK and China more susceptible to urban and river flooding,putting people and property at increased risk.This paper presents a review of the current flooding challenges that are affecting the UK and China and the actions that each country is undertaking to tackle these problems.Particular emphases in this paper are laid on(1)learning from previous flooding events in the UK and China,and(2)which management methodologies are commonly used to reduce flood risk.The paper concludes with a strategic research plan suggested by the authors,together with proposed ways to overcome identified knowledge gaps in flood management.Recommendations briefly comprise the engagement of all stakeholders to ensure a proactive approach to land use planning,early warning systems,and water-sensitive urban design or redesign through more effective policy,multi-level flood models,and data driven models of water quantity and quality.展开更多
A new hybrid optimization algorithm was presented by integrating the gravitational search algorithm （GSA） with the sequential quadratic programming （SQP）, namely GSA-SQP, for solving global optimization problems a...A new hybrid optimization algorithm was presented by integrating the gravitational search algorithm （GSA） with the sequential quadratic programming （SQP）, namely GSA-SQP, for solving global optimization problems and minimization of factor of safety in slope stability analysis. The new algorithm combines the global exploration ability of the GSA to converge rapidly to a near optimum solution. In addition, it uses the accurate local exploitation ability of the SQP to accelerate the search process and find an accurate solution. A set of five well-known benchmark optimization problems was used to validate the performance of the GSA-SQP as a global optimization algorithm and facilitate comparison with the classical GSA. In addition, the effectiveness of the proposed method for slope stability analysis was investigated using three ease studies of slope stability problems from the literature. The factor of safety of earth slopes was evaluated using the Morgenstern-Price method. The numerical experiments demonstrate that the hybrid algorithm converges faster to a significantly more accurate final solution for a variety of benchmark test functions and slope stability problems.展开更多
Biological aerated filter （BAF） is an advanced oxidation process that can sustain high volumetric loads with high quality effluent. However, backwashing process needed for the system limits its applicability. This s...Biological aerated filter （BAF） is an advanced oxidation process that can sustain high volumetric loads with high quality effluent. However, backwashing process needed for the system limits its applicability. This study is to investigate the possibility of removing carbon and nitrogen simultaneously in a biological aerated filter （BAF） with partially packed media without any backwashing process. The upper part of BAF up to 0.5 m depth is packed with plastic media （Kaldnes K1） with diameter and length of 10 mm and 7 mm respectively. This partially packed BAF creates a hybrid system of attached growth and suspended growth combined in a single reactor. Three C：N ratios, i.e. 15, 10 and 4, were compared during this study by varying the nitrogen loading while the carbon loading was kept constant at 1.0±0.54 kg COD/（m^3·d）. The organic loading rate （OLR） ratios were calculated based on carbon and TKN loading. The carbon removal percentage of 86.7±7.3%, 85.1±10.3%, and 91.0±5.6% and TKN removal percentage of 24.7±11.6%, 48.0±25.9% and 62.8±7.9% were achieved after steady-state for the C：N ratio of 15, 10, and 4 respectively. Suspended solid concentration in the effluent was found to be high throughout the treatment, but no clogging occurred during the 4 months of operation period even though backwashing was eliminated.展开更多
The main objective of this experimental study is to investigate the behavior of Recycled Reactive Powder Concrete (RRPC) developed from finely dispersed local waste raw materials. In this study, RRPC was developed by ...The main objective of this experimental study is to investigate the behavior of Recycled Reactive Powder Concrete (RRPC) developed from finely dispersed local waste raw materials. In this study, RRPC was developed by utilizing local wastes (finely dispersed waste glass powder, waste fly ash and waste ceramic powder) together with Portland cement, fine sand, admixture, steel fibers and water through full replacement of silica fume as well as quartz powder for sustainable construction practice. In this study, all raw materials for making RRPC were analyzed for X-Ray Fluorescence analysis. For sustainability of local construction works, this study employed standard curing method at ambient temperatures instead of steam curing at higher temperatures. Moreover, hand mixing was used throughout the study. To evaluate the structural performances of the developed RRPC mixes, compressive and flexural strengths of RRPC were investigated experimentally and compared with the control mix. The experimental results indicated that replacing the silica fume fully by finely dispersed local waste glass powder (GP) and fly ash (FA) is a promising approach for local structural construction applications. Accordingly, a mean compressive strength of 62.9 MPa and flexural strength of 8.8 MPa were developed using 50% GP-50% FA at 28thdays standard curing. In this study, 17.56% larger compressive strength and 30.6% flexural strength improvements were observed as compared to the control mix.展开更多
A numerical procedure for reliability analysis of earth slope based on advanced first-order second-moment method is presented,while soil properties and pore water pressure may be considered as random variables.The fac...A numerical procedure for reliability analysis of earth slope based on advanced first-order second-moment method is presented,while soil properties and pore water pressure may be considered as random variables.The factor of safety and performance function is formulated utilizing a new approach of the Morgenstern and Price method.To evaluate the minimum reliability index defined by Hasofer and Lind and corresponding critical probabilistic slip surface,a hybrid algorithm combining chaotic particle swarm optimization and harmony search algorithm called CPSOHS is presented.The comparison of the results of the presented method,standard particle swarm optimization,and selected other methods employed in previous studies demonstrates the superior successful functioning of the new method by evaluating lower values of reliability index and factor of safety.Moreover,the presented procedure is applied for sensitivity analysis and the obtained results show the influence of soil strength parameters and probability distribution types of random variables on the reliability index of slopes.展开更多
This paper introduces a new approach of firefly algorithm based on opposition-based learning （OBFA） to enhance the global search ability of the original algorithm. The new algorithm employs opposition based learning...This paper introduces a new approach of firefly algorithm based on opposition-based learning （OBFA） to enhance the global search ability of the original algorithm. The new algorithm employs opposition based learning concept to generate initial population and also updating agents’ positions. The proposed OBFA is applied for minimization of the factor of safety and search for critical failure surface in slope stability analysis. The numerical experiments demonstrate the effectiveness and robustness of the new algorithm.展开更多
A new method is proposed to assess the condition of structures under unknown support excitation by simultaneously detecting local damage and identifying the support excitation from several structural dynamic responses...A new method is proposed to assess the condition of structures under unknown support excitation by simultaneously detecting local damage and identifying the support excitation from several structural dynamic responses. The support excitation acting on a structure is modeled by orthogonal polynomial approximations, and the sensitivities of structural dynamic response with respect to its physical parameters and orthogonal coefficients are derived. The identification equation is based on Taylor＇s first order approximation, and is solved with the damped least-squares method in an iterative procedure. A fifteen-story shear building model and a five-story three-dimensional steel frame structure are studied to validate the proposed method. Numerical simulations with noisy measured accelerations show that the proposed method can accurately detect local damage and identify unknown support excitation from only several responses of the structure. This method provides a new approach for detecting structural damage and updating models with unknown input and incomplete measured output information.展开更多
With the opening of ancient Tibetan structures to visitors worldwide, human load has become the principal live load on these structures. This project studies the properties of the floor structure of an ancient Tibetan...With the opening of ancient Tibetan structures to visitors worldwide, human load has become the principal live load on these structures. This project studies the properties of the floor structure of an ancient Tibetan building and its behavior under human-induced load effects. Tests were conducted with static and dynamic crowd load, including stepping and jogging by people at a fixed position. The tests show that the floor structure does not behave as a continuous slab. It takes the load from local areas with minimal load transference properties. The acceleration response shows significant peaks when the footstep frequency is close to the natural frequency of the s~＇ucture, but the human jogging excitation frequency does not have any obvious effect on the structural response. The elastic modulus of the Agatu material is estimated to be close to zero from the measured natural frequency of the slab. The Agatu material is concluded to be a discrete compacted material with insignificant contribution to the structural rigidity of the floor slab.展开更多
A novel PCI Express （peripheral component interconnection express） direct memory access （DMA） transaction method using bridge chip PEX 8311 is proposed. Furthermore, a new method on optimizing PC1 Express DMA tran...A novel PCI Express （peripheral component interconnection express） direct memory access （DMA） transaction method using bridge chip PEX 8311 is proposed. Furthermore, a new method on optimizing PC1 Express DMA transaction through improving both bus-efficiency and DMA-effieiency is presented. A finite state machine （FSM） responding for data and address cycles on PCI Express bus is introduced, and a continuous data burst is realized, which greatly promote bus-efficiency. In software design, a driver framework based on Windows driver model （WDM） and three DMA optimizing options for the proposed PCI Express interface are presented to improve DMA-efficiency. Experiments show that both read and write hardware transaction speed in this paper exceed PCI theoretical maximum speed （133 MBytes/s）.展开更多
Systems that have big transmission line may have problem on changes of pressure in the distribution system. Because the increase in water age is dependent on the difference between the production and consumption rates...Systems that have big transmission line may have problem on changes of pressure in the distribution system. Because the increase in water age is dependent on the difference between the production and consumption rates, high residence time in pipes and storage duration in water tanks. The goal of this study is to analyze the effects residence time to water quality in large water distribution systems. According to the results in Ahwaz, bacterial growth (HPC) has a direct relationship with water age, and changing rate of the bacterial growth (HPC) and the distance travelled and residence time have been caused to increase water age, bacterial growth (HPC), chlorine consumption and hydraulic change. So bacterial growth (HPC) doesn’t have any relationship with THMs and Tol Coli form, but has a reversed relationship with residual chlorine nearly.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2016YFE0122500)the Researcher Links Fund,British Council(Grant No.227109770)+1 种基金the National Natural Science Foundation of China(Grants No.5151101425 and 51579166)the Open Research Fund from the State Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University(Grants No.SKHL1601 and SKHL1602)
文摘Increased urbanisation,economic growth,and long-term climate variability have made both the UK and China more susceptible to urban and river flooding,putting people and property at increased risk.This paper presents a review of the current flooding challenges that are affecting the UK and China and the actions that each country is undertaking to tackle these problems.Particular emphases in this paper are laid on(1)learning from previous flooding events in the UK and China,and(2)which management methodologies are commonly used to reduce flood risk.The paper concludes with a strategic research plan suggested by the authors,together with proposed ways to overcome identified knowledge gaps in flood management.Recommendations briefly comprise the engagement of all stakeholders to ensure a proactive approach to land use planning,early warning systems,and water-sensitive urban design or redesign through more effective policy,multi-level flood models,and data driven models of water quantity and quality.
文摘A new hybrid optimization algorithm was presented by integrating the gravitational search algorithm （GSA） with the sequential quadratic programming （SQP）, namely GSA-SQP, for solving global optimization problems and minimization of factor of safety in slope stability analysis. The new algorithm combines the global exploration ability of the GSA to converge rapidly to a near optimum solution. In addition, it uses the accurate local exploitation ability of the SQP to accelerate the search process and find an accurate solution. A set of five well-known benchmark optimization problems was used to validate the performance of the GSA-SQP as a global optimization algorithm and facilitate comparison with the classical GSA. In addition, the effectiveness of the proposed method for slope stability analysis was investigated using three ease studies of slope stability problems from the literature. The factor of safety of earth slopes was evaluated using the Morgenstern-Price method. The numerical experiments demonstrate that the hybrid algorithm converges faster to a significantly more accurate final solution for a variety of benchmark test functions and slope stability problems.
文摘Biological aerated filter （BAF） is an advanced oxidation process that can sustain high volumetric loads with high quality effluent. However, backwashing process needed for the system limits its applicability. This study is to investigate the possibility of removing carbon and nitrogen simultaneously in a biological aerated filter （BAF） with partially packed media without any backwashing process. The upper part of BAF up to 0.5 m depth is packed with plastic media （Kaldnes K1） with diameter and length of 10 mm and 7 mm respectively. This partially packed BAF creates a hybrid system of attached growth and suspended growth combined in a single reactor. Three C：N ratios, i.e. 15, 10 and 4, were compared during this study by varying the nitrogen loading while the carbon loading was kept constant at 1.0±0.54 kg COD/（m^3·d）. The organic loading rate （OLR） ratios were calculated based on carbon and TKN loading. The carbon removal percentage of 86.7±7.3%, 85.1±10.3%, and 91.0±5.6% and TKN removal percentage of 24.7±11.6%, 48.0±25.9% and 62.8±7.9% were achieved after steady-state for the C：N ratio of 15, 10, and 4 respectively. Suspended solid concentration in the effluent was found to be high throughout the treatment, but no clogging occurred during the 4 months of operation period even though backwashing was eliminated.
文摘The main objective of this experimental study is to investigate the behavior of Recycled Reactive Powder Concrete (RRPC) developed from finely dispersed local waste raw materials. In this study, RRPC was developed by utilizing local wastes (finely dispersed waste glass powder, waste fly ash and waste ceramic powder) together with Portland cement, fine sand, admixture, steel fibers and water through full replacement of silica fume as well as quartz powder for sustainable construction practice. In this study, all raw materials for making RRPC were analyzed for X-Ray Fluorescence analysis. For sustainability of local construction works, this study employed standard curing method at ambient temperatures instead of steam curing at higher temperatures. Moreover, hand mixing was used throughout the study. To evaluate the structural performances of the developed RRPC mixes, compressive and flexural strengths of RRPC were investigated experimentally and compared with the control mix. The experimental results indicated that replacing the silica fume fully by finely dispersed local waste glass powder (GP) and fly ash (FA) is a promising approach for local structural construction applications. Accordingly, a mean compressive strength of 62.9 MPa and flexural strength of 8.8 MPa were developed using 50% GP-50% FA at 28thdays standard curing. In this study, 17.56% larger compressive strength and 30.6% flexural strength improvements were observed as compared to the control mix.
基金supported by the Ministry of Higher Education, Malaysia (Grant No.UKM-AP-PLW-04-2009/2)
文摘A numerical procedure for reliability analysis of earth slope based on advanced first-order second-moment method is presented,while soil properties and pore water pressure may be considered as random variables.The factor of safety and performance function is formulated utilizing a new approach of the Morgenstern and Price method.To evaluate the minimum reliability index defined by Hasofer and Lind and corresponding critical probabilistic slip surface,a hybrid algorithm combining chaotic particle swarm optimization and harmony search algorithm called CPSOHS is presented.The comparison of the results of the presented method,standard particle swarm optimization,and selected other methods employed in previous studies demonstrates the superior successful functioning of the new method by evaluating lower values of reliability index and factor of safety.Moreover,the presented procedure is applied for sensitivity analysis and the obtained results show the influence of soil strength parameters and probability distribution types of random variables on the reliability index of slopes.
文摘This paper introduces a new approach of firefly algorithm based on opposition-based learning （OBFA） to enhance the global search ability of the original algorithm. The new algorithm employs opposition based learning concept to generate initial population and also updating agents’ positions. The proposed OBFA is applied for minimization of the factor of safety and search for critical failure surface in slope stability analysis. The numerical experiments demonstrate the effectiveness and robustness of the new algorithm.
基金National Natural Science Foundation of China Under Grant No.50579008Joint Research Fund for Overseas Chinese, Hong Kong and Macao Young Scholars Under Grant No.50429802+1 种基金Program for New Century Excellent Talents in University by State Education Commission Under Grant No.NCET-04-0323a research grant from the Hong Kong Polytechnic University
文摘A new method is proposed to assess the condition of structures under unknown support excitation by simultaneously detecting local damage and identifying the support excitation from several structural dynamic responses. The support excitation acting on a structure is modeled by orthogonal polynomial approximations, and the sensitivities of structural dynamic response with respect to its physical parameters and orthogonal coefficients are derived. The identification equation is based on Taylor＇s first order approximation, and is solved with the damped least-squares method in an iterative procedure. A fifteen-story shear building model and a five-story three-dimensional steel frame structure are studied to validate the proposed method. Numerical simulations with noisy measured accelerations show that the proposed method can accurately detect local damage and identify unknown support excitation from only several responses of the structure. This method provides a new approach for detecting structural damage and updating models with unknown input and incomplete measured output information.
基金National Natural Science Foundation of China Under Grant No.51178028 and No.50938008Program for New Century Excellent Talents in University(NCET-11-0571)+1 种基金the Fundamental Research Funds for the Central Universities(2012JBM007)the 111 Project(B13002)
文摘With the opening of ancient Tibetan structures to visitors worldwide, human load has become the principal live load on these structures. This project studies the properties of the floor structure of an ancient Tibetan building and its behavior under human-induced load effects. Tests were conducted with static and dynamic crowd load, including stepping and jogging by people at a fixed position. The tests show that the floor structure does not behave as a continuous slab. It takes the load from local areas with minimal load transference properties. The acceleration response shows significant peaks when the footstep frequency is close to the natural frequency of the s~＇ucture, but the human jogging excitation frequency does not have any obvious effect on the structural response. The elastic modulus of the Agatu material is estimated to be close to zero from the measured natural frequency of the slab. The Agatu material is concluded to be a discrete compacted material with insignificant contribution to the structural rigidity of the floor slab.
文摘A novel PCI Express （peripheral component interconnection express） direct memory access （DMA） transaction method using bridge chip PEX 8311 is proposed. Furthermore, a new method on optimizing PC1 Express DMA transaction through improving both bus-efficiency and DMA-effieiency is presented. A finite state machine （FSM） responding for data and address cycles on PCI Express bus is introduced, and a continuous data burst is realized, which greatly promote bus-efficiency. In software design, a driver framework based on Windows driver model （WDM） and three DMA optimizing options for the proposed PCI Express interface are presented to improve DMA-efficiency. Experiments show that both read and write hardware transaction speed in this paper exceed PCI theoretical maximum speed （133 MBytes/s）.
文摘Systems that have big transmission line may have problem on changes of pressure in the distribution system. Because the increase in water age is dependent on the difference between the production and consumption rates, high residence time in pipes and storage duration in water tanks. The goal of this study is to analyze the effects residence time to water quality in large water distribution systems. According to the results in Ahwaz, bacterial growth (HPC) has a direct relationship with water age, and changing rate of the bacterial growth (HPC) and the distance travelled and residence time have been caused to increase water age, bacterial growth (HPC), chlorine consumption and hydraulic change. So bacterial growth (HPC) doesn’t have any relationship with THMs and Tol Coli form, but has a reversed relationship with residual chlorine nearly.
