This paper introduces a slurry suspension settlement prediction model for cohesive sediment in a still water environment. With no sediment input and a still water environment condition, control forces between settling...This paper introduces a slurry suspension settlement prediction model for cohesive sediment in a still water environment. With no sediment input and a still water environment condition, control forces between settling particles are significantly different in the process of sedimentation rate attenuation, and the settlement process includes the free sedimentation stage, the log-linear attenuation stage, and the stable consolidation stage according to sedimentation rate attenuation. Settlement equations for sedimentation height and time were established based on sedimentation rate attenuation properties of different sedimentation stages. Finally, a slurry suspension settlement prediction model based on slurry parameters was set up with a foundation being that the model parameters were determined by the basic parameters of slurry. The results of the settlement prediction model show good agreement with those of the settlement column experiment and reflect the main characteristics of cohesive sediment. The model can be applied to the prediction of cohesive soil settlement in still water environments.展开更多
To solve a real problem:how to calculate the reliability of a system with time-varying failure rates in industry systems,this paper studies a model for the load-sharing parallel system with time-varying failure rates,...To solve a real problem:how to calculate the reliability of a system with time-varying failure rates in industry systems,this paper studies a model for the load-sharing parallel system with time-varying failure rates,and obtains calculating formulas of reliability and availability of the system by solving differential equations.In this paper,the failure rates are expressed in polynomial configuration.The constant,linear and Weibull failure rate are in their special form.The polynomial failure rates provide flexibility in modeling the practical time-varying failure rates.展开更多
In the paper the problem on the assignment of the bounds of decreasing rate for a time-varying linear control system is discussed. The sufficient and necessary condition for bounds of decreasing rate of a time-varying...In the paper the problem on the assignment of the bounds of decreasing rate for a time-varying linear control system is discussed. The sufficient and necessary condition for bounds of decreasing rate of a time-varying linear system to be assigned arbitrarily is presented. It is pointed out that for any given real number m, M, m<M, there exists a linear state feedback with time-varying gain matrix which makes the corresponding closed-loop system possess M and m as its upper bound and lower bound of the decreasing rate respectively. For the purposes of its application to system design the concept of the asymptotic assignment of the bounds of decreasing rate is also proposed. The method dealing with the asymptotic assignment is given too.展开更多
In order to study deposited sediment settlement and consolidation mechanisms, sediment settlement experiments were conducted using a settlement column. Based on the experimental results, sediment settlement stage defi...In order to study deposited sediment settlement and consolidation mechanisms, sediment settlement experiments were conducted using a settlement column. Based on the experimental results, sediment settlement stage definition, excessive pore pressure （EPP） dissipation, and consolidation constitutive equations are discussed. Three stages, including the free settlement, hindered settlement, and self-weight consolidation settlement stages, are defined. The results of this study show that sediment settlement is mainly affected by the initial sediment concentration and initial settlement height, and the interface settlement rate is linearly attenuated with time on bilogarithmic scales during the hindered settlement and self-weight consolidation settlement stages. Moreover, the deposited sediment layer in the self-weight consolidation settlement stage experiences large strains, and the settlement amount in this stage is about 32% to 59% of the initial height of deposited sediment. EPP is nonlinearly distributed in the settlement direction, and consolidation settlement is faster than EPP dissipation in the self-weight consolidation settlement stage. Consolidation constitutive equations for the hydraulic conductivity and effective stress, applicable to large-strain consolidation calculation, were also determined and fitted in the power function form.展开更多
The global exponential stability of Cohen-Grossberg neural networks with time-varying delays is studied. By constructing several suitable Lyapunov functionals and utilizing differential in-equality techniques, some su...The global exponential stability of Cohen-Grossberg neural networks with time-varying delays is studied. By constructing several suitable Lyapunov functionals and utilizing differential in-equality techniques, some sufficient criteria for the global exponential stability and the exponential convergence rate of the equilibrium point of the system are obtained. The criteria do not require the activation functions to be differentiable or monotone nondecreasing. Some stability results from previous works are extended and improved. Comparisons are made to demonstrate the advantage of our results.展开更多
The effects of temperature and substrate on ontogenetic patterns and settlement behavior of bastard halibut, Paralichthys olivaceus (T. et S.) were studied in a series of laboratory experiments. Analysis on stage-base...The effects of temperature and substrate on ontogenetic patterns and settlement behavior of bastard halibut, Paralichthys olivaceus (T. et S.) were studied in a series of laboratory experiments. Analysis on stage-based data revealed that except for settlement, and compared to the substrate, the ambient temperature dominantly controlled the hatch success and subsequent development of the species. The oosperm optimum survival rate of 60% during hatching occurred at 20℃, and survival rate of 29%, at 18℃ for larval rearing. The survival rate of larvae reared under variable temperature of 3.5–4.5℃ was higher than that of those reared under stable temperature. The maximum survival rate of 29%, corresponded to variation at temperature of 4℃. With increase in age newly settled juveniles preferred to lie on the fine substrate and gradually moved on the coarse substrate. GLM (general linear model) analysis showed that the combination of temperature and substrate had no significant impact on the survival of settling larvae, but definitely affected the duration of settlement.展开更多
The ancient Kilistra settlement is a natural,historical and cultural heritage site in Central Anatolia(Turkey), which makes it an attractive destination for tourists. However, the settlement located on a hill with ste...The ancient Kilistra settlement is a natural,historical and cultural heritage site in Central Anatolia(Turkey), which makes it an attractive destination for tourists. However, the settlement located on a hill with steep hillsides has suffered from rockfall events,causing the destruction of some historical buildings.The rockfall risk in the region continues to create a serious danger today for land users and visitors during uncontrolled tourist visits. This paper offers an assessment of rockfall hazard for the ancient Kilistra settlement based on experimental investigation and numerical analyses. For the study, comprehensive field studies were carried out, including the identification of slope profiles, scanline surveys on discontinuities and stability analysis of the slopes. The location and size of the fallen, detached and hanging blocks were also identified. Geomechanical properties of the geological units were determined, and also the rockfall risk rating method was applied for the evaluation of the rockfall hazard risk. Runout distance, bounce height, kinetic energy as well as the velocity of the detached and hanging blocks were determined by using twodimensional rockfall analyses. Based on the results from the rockfall analyses, possible rockfall-based danger zones have been defined for the ancient Kilistra settlement and its close vicinity. The results of this study point at an immediate necessity for the installation of support systems. Findings of the study also offer preliminary data for the description of risk administration strategies and also provide scientific contribution to the study of the hazard and risk resulting from rockfall phenomena.展开更多
The size and allocation method of transmission network loss have major impact on particular users involved with the electricity market trading process, therefore, the accuracy of scheduled network loss rates will be v...The size and allocation method of transmission network loss have major impact on particular users involved with the electricity market trading process, therefore, the accuracy of scheduled network loss rates will be vital to the economic concerns from the stakeholders. In view of the shortcoming of existing loss rate scheme in 1,000 kV demonstration project, three scheduled loss rates applied to the UHV AC （ultra high voltage alternating current） transaction settlement are revised. By taking relationship between loss rate and power into consideration, the new segmented correction scheme greatly reduces the deviation between scheduled loss rates and actual loss rates, and is more accurate, flexible and expansible than the old one.展开更多
基金supported by the Research Funds for the Central Universities (Grant No. 2009B13514)the Doctoral Fund of the Ministry of Education of China (Grant No. 20100094110002)
文摘This paper introduces a slurry suspension settlement prediction model for cohesive sediment in a still water environment. With no sediment input and a still water environment condition, control forces between settling particles are significantly different in the process of sedimentation rate attenuation, and the settlement process includes the free sedimentation stage, the log-linear attenuation stage, and the stable consolidation stage according to sedimentation rate attenuation. Settlement equations for sedimentation height and time were established based on sedimentation rate attenuation properties of different sedimentation stages. Finally, a slurry suspension settlement prediction model based on slurry parameters was set up with a foundation being that the model parameters were determined by the basic parameters of slurry. The results of the settlement prediction model show good agreement with those of the settlement column experiment and reflect the main characteristics of cohesive sediment. The model can be applied to the prediction of cohesive soil settlement in still water environments.
文摘To solve a real problem:how to calculate the reliability of a system with time-varying failure rates in industry systems,this paper studies a model for the load-sharing parallel system with time-varying failure rates,and obtains calculating formulas of reliability and availability of the system by solving differential equations.In this paper,the failure rates are expressed in polynomial configuration.The constant,linear and Weibull failure rate are in their special form.The polynomial failure rates provide flexibility in modeling the practical time-varying failure rates.
文摘In the paper the problem on the assignment of the bounds of decreasing rate for a time-varying linear control system is discussed. The sufficient and necessary condition for bounds of decreasing rate of a time-varying linear system to be assigned arbitrarily is presented. It is pointed out that for any given real number m, M, m<M, there exists a linear state feedback with time-varying gain matrix which makes the corresponding closed-loop system possess M and m as its upper bound and lower bound of the decreasing rate respectively. For the purposes of its application to system design the concept of the asymptotic assignment of the bounds of decreasing rate is also proposed. The method dealing with the asymptotic assignment is given too.
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.2009B13514)the Doctoral Fund of the Ministry of Education of China(Grant No.20100094110002)
文摘In order to study deposited sediment settlement and consolidation mechanisms, sediment settlement experiments were conducted using a settlement column. Based on the experimental results, sediment settlement stage definition, excessive pore pressure （EPP） dissipation, and consolidation constitutive equations are discussed. Three stages, including the free settlement, hindered settlement, and self-weight consolidation settlement stages, are defined. The results of this study show that sediment settlement is mainly affected by the initial sediment concentration and initial settlement height, and the interface settlement rate is linearly attenuated with time on bilogarithmic scales during the hindered settlement and self-weight consolidation settlement stages. Moreover, the deposited sediment layer in the self-weight consolidation settlement stage experiences large strains, and the settlement amount in this stage is about 32% to 59% of the initial height of deposited sediment. EPP is nonlinearly distributed in the settlement direction, and consolidation settlement is faster than EPP dissipation in the self-weight consolidation settlement stage. Consolidation constitutive equations for the hydraulic conductivity and effective stress, applicable to large-strain consolidation calculation, were also determined and fitted in the power function form.
基金National Natural Science Foundation of China (No70471049)
文摘The global exponential stability of Cohen-Grossberg neural networks with time-varying delays is studied. By constructing several suitable Lyapunov functionals and utilizing differential in-equality techniques, some sufficient criteria for the global exponential stability and the exponential convergence rate of the equilibrium point of the system are obtained. The criteria do not require the activation functions to be differentiable or monotone nondecreasing. Some stability results from previous works are extended and improved. Comparisons are made to demonstrate the advantage of our results.
文摘The effects of temperature and substrate on ontogenetic patterns and settlement behavior of bastard halibut, Paralichthys olivaceus (T. et S.) were studied in a series of laboratory experiments. Analysis on stage-based data revealed that except for settlement, and compared to the substrate, the ambient temperature dominantly controlled the hatch success and subsequent development of the species. The oosperm optimum survival rate of 60% during hatching occurred at 20℃, and survival rate of 29%, at 18℃ for larval rearing. The survival rate of larvae reared under variable temperature of 3.5–4.5℃ was higher than that of those reared under stable temperature. The maximum survival rate of 29%, corresponded to variation at temperature of 4℃. With increase in age newly settled juveniles preferred to lie on the fine substrate and gradually moved on the coarse substrate. GLM (general linear model) analysis showed that the combination of temperature and substrate had no significant impact on the survival of settling larvae, but definitely affected the duration of settlement.
文摘The ancient Kilistra settlement is a natural,historical and cultural heritage site in Central Anatolia(Turkey), which makes it an attractive destination for tourists. However, the settlement located on a hill with steep hillsides has suffered from rockfall events,causing the destruction of some historical buildings.The rockfall risk in the region continues to create a serious danger today for land users and visitors during uncontrolled tourist visits. This paper offers an assessment of rockfall hazard for the ancient Kilistra settlement based on experimental investigation and numerical analyses. For the study, comprehensive field studies were carried out, including the identification of slope profiles, scanline surveys on discontinuities and stability analysis of the slopes. The location and size of the fallen, detached and hanging blocks were also identified. Geomechanical properties of the geological units were determined, and also the rockfall risk rating method was applied for the evaluation of the rockfall hazard risk. Runout distance, bounce height, kinetic energy as well as the velocity of the detached and hanging blocks were determined by using twodimensional rockfall analyses. Based on the results from the rockfall analyses, possible rockfall-based danger zones have been defined for the ancient Kilistra settlement and its close vicinity. The results of this study point at an immediate necessity for the installation of support systems. Findings of the study also offer preliminary data for the description of risk administration strategies and also provide scientific contribution to the study of the hazard and risk resulting from rockfall phenomena.
文摘The size and allocation method of transmission network loss have major impact on particular users involved with the electricity market trading process, therefore, the accuracy of scheduled network loss rates will be vital to the economic concerns from the stakeholders. In view of the shortcoming of existing loss rate scheme in 1,000 kV demonstration project, three scheduled loss rates applied to the UHV AC （ultra high voltage alternating current） transaction settlement are revised. By taking relationship between loss rate and power into consideration, the new segmented correction scheme greatly reduces the deviation between scheduled loss rates and actual loss rates, and is more accurate, flexible and expansible than the old one.
