Limit equilibrium method （LEM） and strength reduction method （SRM） are the most widely used methods for slope stability analysis. However, it can be noted that they both have some limitations in practical applicat...Limit equilibrium method （LEM） and strength reduction method （SRM） are the most widely used methods for slope stability analysis. However, it can be noted that they both have some limitations in practical application. In the LEM, the constitutive model cannot be considered and many assumptions are needed between slices of soil/rock. The SRM requires iterative calculations and does not give the slip surface directly. A method for slope stability analysis based on the graph theory is recently developed to directly calculate the minimum safety factor and potential critical slip surface according to the stress results of numerical simulation. The method is based on current stress state and can overcome the disadvantages mentioned above in the two traditional methods. The influences of edge generation and mesh geometry on the position of slip surface and the safety factor of slope are studied, in which a new method for edge generation is proposed, and reasonable mesh size is suggested. The results of benchmark examples and a rock slope show good accuracy and efficiency of the presented method.展开更多
Flatfish constitute a substantial proportion of the catch in several demersal trawl fisheries across the globe.Therefore,knowledge on how to discriminate between the individuals that are to be captured or released,by ...Flatfish constitute a substantial proportion of the catch in several demersal trawl fisheries across the globe.Therefore,knowledge on how to discriminate between the individuals that are to be captured or released,by size,is important for the sustainability of exploited stocks.Using European plaice(Pleuronectes platessa),flounder(Platichthys flesus),and dab(Limanda limanda)as case-study species,here we investigate how flatfish are selected in trawl codends by experimentally testing the influence of mesh geometry,and its variability,on size selection.Both diamond-mesh and square-mesh codends were tested,as well as three codends where the mesh shape was fixed to minimize its variation during fishing.The most discriminating size selectivity was found with fixed mesh geometry,revealing that variability in mesh openness negatively affects the selectivity of flatfish.Our results further demonstrate that the risk of retaining undersized flatfish tends to increase with increasing mesh opening angle in diamond-mesh codends.Our results also confirm that when fishing with codends of the same nominal mesh size,the square-mesh codend retains significantly higher proportions of undersized flatfish than the traditional diamond-mesh.展开更多
Based on newly developed weight-based smoothness detectors and non-linear interpolations designed to capture discontinuities for the multiderivative com-bined dissipative compact scheme(MDCS),hybrid linear and nonline...Based on newly developed weight-based smoothness detectors and non-linear interpolations designed to capture discontinuities for the multiderivative com-bined dissipative compact scheme(MDCS),hybrid linear and nonlinear interpolations are proposed to form hybrid MDCS.These detectors are derived from the weights used for the nonlinear interpolations and can provide suitable switches between the linear and the nonlinear schemes to realize the characteristics for the hybrid MDCS of capturing discontinuities and maintaining high resolution in the region without large discontinuities.To save computational cost,the nonlinear scheme with characteris-tic decomposition is only applied in the detected discontinuities region by specially designed hybrid strategy.Typical tests show that the hybrid MDCS is capable of cap-turing discontinuities and maintaining high resolution power for the smooth region at the same time.With the satisfaction of the geometric conservative law(GCL),the MDCS is further applied on curvilinear mesh to present its promising capability of handling pragmatic simulations.展开更多
基金support of the National Natural Science Foundation of China (Grant No. 41130751)China Scholarship Council, Research Program for Western China Communication (Grant No. 2011ZB04)China Central University Funding
文摘Limit equilibrium method （LEM） and strength reduction method （SRM） are the most widely used methods for slope stability analysis. However, it can be noted that they both have some limitations in practical application. In the LEM, the constitutive model cannot be considered and many assumptions are needed between slices of soil/rock. The SRM requires iterative calculations and does not give the slip surface directly. A method for slope stability analysis based on the graph theory is recently developed to directly calculate the minimum safety factor and potential critical slip surface according to the stress results of numerical simulation. The method is based on current stress state and can overcome the disadvantages mentioned above in the two traditional methods. The influences of edge generation and mesh geometry on the position of slip surface and the safety factor of slope are studied, in which a new method for edge generation is proposed, and reasonable mesh size is suggested. The results of benchmark examples and a rock slope show good accuracy and efficiency of the presented method.
基金the European Maritime and Fisheries Fund(EMFF)and the Ministry of Food,Agriculture and Fisheries of Denmark(Ministeriet for Fødevarer,Landbrug og Fiskeri)as part of the projects(FastTrack II–Sustainable,cost effective and responsive gear solutions under the landing obligation(33112-P-18-051)and Udvikling af SELEKTive redskaber og teknologier til kommercielle fiskerier(SELEKT)).
文摘Flatfish constitute a substantial proportion of the catch in several demersal trawl fisheries across the globe.Therefore,knowledge on how to discriminate between the individuals that are to be captured or released,by size,is important for the sustainability of exploited stocks.Using European plaice(Pleuronectes platessa),flounder(Platichthys flesus),and dab(Limanda limanda)as case-study species,here we investigate how flatfish are selected in trawl codends by experimentally testing the influence of mesh geometry,and its variability,on size selection.Both diamond-mesh and square-mesh codends were tested,as well as three codends where the mesh shape was fixed to minimize its variation during fishing.The most discriminating size selectivity was found with fixed mesh geometry,revealing that variability in mesh openness negatively affects the selectivity of flatfish.Our results further demonstrate that the risk of retaining undersized flatfish tends to increase with increasing mesh opening angle in diamond-mesh codends.Our results also confirm that when fishing with codends of the same nominal mesh size,the square-mesh codend retains significantly higher proportions of undersized flatfish than the traditional diamond-mesh.
基金supported by the National Key Research and Development Plan(grant No.2016YFB0200700)the National Natural Science Foundation of China(grant Nos.11372342,11572342,and 11672321)the National Key Project GJXM92579.
文摘Based on newly developed weight-based smoothness detectors and non-linear interpolations designed to capture discontinuities for the multiderivative com-bined dissipative compact scheme(MDCS),hybrid linear and nonlinear interpolations are proposed to form hybrid MDCS.These detectors are derived from the weights used for the nonlinear interpolations and can provide suitable switches between the linear and the nonlinear schemes to realize the characteristics for the hybrid MDCS of capturing discontinuities and maintaining high resolution in the region without large discontinuities.To save computational cost,the nonlinear scheme with characteris-tic decomposition is only applied in the detected discontinuities region by specially designed hybrid strategy.Typical tests show that the hybrid MDCS is capable of cap-turing discontinuities and maintaining high resolution power for the smooth region at the same time.With the satisfaction of the geometric conservative law(GCL),the MDCS is further applied on curvilinear mesh to present its promising capability of handling pragmatic simulations.
