Since the decrease of the global sulfur limit from 3.5%to 0.5%by the IMO(International Maritime Organization)on January 1,2020,the shipowners and carriers are obliged to elect between the three available options to co...Since the decrease of the global sulfur limit from 3.5%to 0.5%by the IMO(International Maritime Organization)on January 1,2020,the shipowners and carriers are obliged to elect between the three available options to comply with the present regulatory amendments.The first available option is utilising exhaust gas cleaning systems called“scrubbers”.By using these filters,the vessels can burn high sulfur fuels.In contrast,the sulfur surplus and other dangerous chemicals are evaporated by spraying alkaline water via an open-loop,closed-loop or hybrid systems.The other option is using LNG(liquefied natural gas)as fuel,a viable option connected with the constant expansion of the global LNG supply infrastructure network.However,this network is yet in its developing status.Moreover,the majority of the LNG vessels are primarily coastal vessels operated in European waters,and many supply ports worldwide have not yet developed full-scale LNG supply facilities and proper equipment is not yet installed.Finally,ammonia is another potential candidate as zero carbon fuel,but its utilization as a sustainable marine fuel in marine industry is currently under research.Therefore,at present the final option is the utilisation of conventional fuels,low on sulfur emissions,such as MGO(marine gasoil)and ULSFO(ultra low sulphur fuel oil).The primary issue is the availability and the cost of those fuels,with the refiners being unable to forecast if they should produce more low-sulfur fuels to meet potentially higher demand.By the comparative analysis of those options their viability will be evaluated,and a thorough proposal for their utilisation will be provided.展开更多
Rectangular-closed-diaphragm-wall foundation is a new type of bridge foundation.Diaphragm wallsoil-cap interaction was studied using a model test.It was observed that the distribution of soil resistance under the cap ...Rectangular-closed-diaphragm-wall foundation is a new type of bridge foundation.Diaphragm wallsoil-cap interaction was studied using a model test.It was observed that the distribution of soil resistance under the cap is not homogeneous.The soil resistance in the corner under the cap is larger than that in the border;and that in the center is the smallest.The distribution of soil resistance under the cap will be more uniform,if the sectional area of soil core is enlarged within a certain range.Due to the existence of cap,there is a“weakening effect”in inner shaft resistance of the upper wall segments,and there is“enhancement effect”in the lower wall segments and in toe resistance.The load shearing percentage of soil resistance under the cap is 10%–20%.It is unreasonable to ignore the effects of the cap and the soil resistance under the cap in bearing capacity calculations.展开更多
文摘Since the decrease of the global sulfur limit from 3.5%to 0.5%by the IMO(International Maritime Organization)on January 1,2020,the shipowners and carriers are obliged to elect between the three available options to comply with the present regulatory amendments.The first available option is utilising exhaust gas cleaning systems called“scrubbers”.By using these filters,the vessels can burn high sulfur fuels.In contrast,the sulfur surplus and other dangerous chemicals are evaporated by spraying alkaline water via an open-loop,closed-loop or hybrid systems.The other option is using LNG(liquefied natural gas)as fuel,a viable option connected with the constant expansion of the global LNG supply infrastructure network.However,this network is yet in its developing status.Moreover,the majority of the LNG vessels are primarily coastal vessels operated in European waters,and many supply ports worldwide have not yet developed full-scale LNG supply facilities and proper equipment is not yet installed.Finally,ammonia is another potential candidate as zero carbon fuel,but its utilization as a sustainable marine fuel in marine industry is currently under research.Therefore,at present the final option is the utilisation of conventional fuels,low on sulfur emissions,such as MGO(marine gasoil)and ULSFO(ultra low sulphur fuel oil).The primary issue is the availability and the cost of those fuels,with the refiners being unable to forecast if they should produce more low-sulfur fuels to meet potentially higher demand.By the comparative analysis of those options their viability will be evaluated,and a thorough proposal for their utilisation will be provided.
基金supported by the National Basic Research program(2008CB425801)。
文摘Rectangular-closed-diaphragm-wall foundation is a new type of bridge foundation.Diaphragm wallsoil-cap interaction was studied using a model test.It was observed that the distribution of soil resistance under the cap is not homogeneous.The soil resistance in the corner under the cap is larger than that in the border;and that in the center is the smallest.The distribution of soil resistance under the cap will be more uniform,if the sectional area of soil core is enlarged within a certain range.Due to the existence of cap,there is a“weakening effect”in inner shaft resistance of the upper wall segments,and there is“enhancement effect”in the lower wall segments and in toe resistance.The load shearing percentage of soil resistance under the cap is 10%–20%.It is unreasonable to ignore the effects of the cap and the soil resistance under the cap in bearing capacity calculations.
