Major advancements have been made in the field of prosthetics, but devices remain largely out of reach for the amputee population domiciled in the developing nations, which makes up 80% of the entire amputee populatio...Major advancements have been made in the field of prosthetics, but devices remain largely out of reach for the amputee population domiciled in the developing nations, which makes up 80% of the entire amputee population of the world. The amputees are left to contend with low function prosthetics that do not mimic the behavior of the natural lost limb, with the long-term use of such devices leading to physical injury to the user. This work was aimed at developing a low-cost ankle-foot prosthesis that affords the user the opportunity to manually alter the stiffness of the ankle, as well storing energy in a forefoot section to aid push-off in late stance. In this paper, the design and results of structural analysis performed on critical parts of the prosthesis are presented, as well as the future direction of the work.展开更多
This paper proposed a method of injection-production system adjustment to solve the problem that the water flooding effect was restricted because of the horizontal and vertical contradictions during the development pr...This paper proposed a method of injection-production system adjustment to solve the problem that the water flooding effect was restricted because of the horizontal and vertical contradictions during the development process of fault block reservoirs. Considering the heterogeneity of reservoir, the Buckley-Leverett water flooding theory was applied to establish the relationship between the recovery and cumulative water injection. In order to achieve the goal of vertically balanced recovery of each section, the calculation method of vertical sectional injection allocation was proposed. The planar triangular seepage unit was assumed and sweep coefficients of different oil-water distribution patterns were characterized using multi-flow tube method. In order to balance and maximize the plane sweep coefficient, the calculation method of plane production system optimization was obtained. Then the injection-production system stereoscopic adjustment method based on equilibrium displacement was proposed with vertical sectional injection allocation and plane production system optimization. This method was applied to injection and production adjustment of BZ oilfield in southern Bohai. The effect of water control and oil increase was obvious. This method can greatly improve the effect of water flooding of offshore fault block reservoirs with the adjustment of injection-production system.展开更多
文摘Major advancements have been made in the field of prosthetics, but devices remain largely out of reach for the amputee population domiciled in the developing nations, which makes up 80% of the entire amputee population of the world. The amputees are left to contend with low function prosthetics that do not mimic the behavior of the natural lost limb, with the long-term use of such devices leading to physical injury to the user. This work was aimed at developing a low-cost ankle-foot prosthesis that affords the user the opportunity to manually alter the stiffness of the ankle, as well storing energy in a forefoot section to aid push-off in late stance. In this paper, the design and results of structural analysis performed on critical parts of the prosthesis are presented, as well as the future direction of the work.
文摘This paper proposed a method of injection-production system adjustment to solve the problem that the water flooding effect was restricted because of the horizontal and vertical contradictions during the development process of fault block reservoirs. Considering the heterogeneity of reservoir, the Buckley-Leverett water flooding theory was applied to establish the relationship between the recovery and cumulative water injection. In order to achieve the goal of vertically balanced recovery of each section, the calculation method of vertical sectional injection allocation was proposed. The planar triangular seepage unit was assumed and sweep coefficients of different oil-water distribution patterns were characterized using multi-flow tube method. In order to balance and maximize the plane sweep coefficient, the calculation method of plane production system optimization was obtained. Then the injection-production system stereoscopic adjustment method based on equilibrium displacement was proposed with vertical sectional injection allocation and plane production system optimization. This method was applied to injection and production adjustment of BZ oilfield in southern Bohai. The effect of water control and oil increase was obvious. This method can greatly improve the effect of water flooding of offshore fault block reservoirs with the adjustment of injection-production system.
