Deepsea mining has been proposed since the 1960s to alleviate the lack of resources on land.Vertical hydraulic transport of collected ores from the seabed to the sea surface is considered the most promising method for...Deepsea mining has been proposed since the 1960s to alleviate the lack of resources on land.Vertical hydraulic transport of collected ores from the seabed to the sea surface is considered the most promising method for industrial applications.In the present study,an indoor model test of the vertical hydraulic transport of particles was conducted.A noncontact optical method has been proposed to measure the local characteristics of the particles inside a vertical pipe,including the local concentration and particle velocity.The hydraulic gradient of ore transport was evaluated with various particle size distributions,particle densities,feeding concentrations and mixture flow velocities.During transport,the local concentration is larger than the feeding concentration,whereas the particle velocity is less than the mixture velocity.The qualitative effects of the local concentration and local fluid velocity on the particle velocity and slip velocity were investigated.The local fluid velocity contributes significantly to particle velocity and slip velocity,whereas the effect of the local concentration is marginal.A higher feeding concentration and mixture flow velocity result in an increased hydraulic gradient.The effect of the particle size gradation is slight,whereas the particle density plays a crucial role in the transport.展开更多
Gravity-1 was the world's first carrier rocket to adopt the sea-based “three vertical” testing launch mode. This article introduces the overall layout of the launch site and the workflow of rocket testing and la...Gravity-1 was the world's first carrier rocket to adopt the sea-based “three vertical” testing launch mode. This article introduces the overall layout of the launch site and the workflow of rocket testing and launch for its maiden flight mission. The process of vertical assembly, vertical testing, vertical transportation, and sea-based hot launches are explained. Additionally, it provides an outlook on the improved “three vertical” testing and launch mode for future missions, such as land-based launches, rapid launches, and remote sea launches.展开更多
An integrated analysis of internal solitary wave(ISW) observations obtained from two moorings over the continental slope in the northern South China Sea(SCS) leads to an assessment of the vertical heat transport of th...An integrated analysis of internal solitary wave(ISW) observations obtained from two moorings over the continental slope in the northern South China Sea(SCS) leads to an assessment of the vertical heat transport of the ISWs. The clusters of ISW packets are phase-locked to the fortnightly cycle of the semidiurnal tide. The ISWs appear during large semidiurnal tides, and there is a period of 5–6 d when no ISWs are observed. The effect of the ISWs on the continental slope heat budget is observed. The ISWs can modify a local temperature field in which the temperature in the upper layer can be changed by O(100) °C after the ISWs passed the mooring. Both ISWinduced diffusion and ISW-induced advection contribute to the temperature variation. The estimates imply an average vertical heat flux of 0.01 to 0.1 MW/m^2 in the ISWs in the upper 500 m of the water column. The vertical heat transport ranges from 0.56 to 2.83 GJ/m^2 with a mean value of 1.63 GJ/m^2. The observations suggest that the vertical heat transport is proportional to the maximum vertical displacement.展开更多
Deep water in the South China Sea is renewed by the cold and dense Luzon Strait overflow.However,from where and how the deep water upwells is poorly understood yet.Based on the Hybrid Coordinate Ocean Model reanalysis...Deep water in the South China Sea is renewed by the cold and dense Luzon Strait overflow.However,from where and how the deep water upwells is poorly understood yet.Based on the Hybrid Coordinate Ocean Model reanalysis data,vertical velocity is derived to answer these questions.Domain-integrated vertical velocity is of two maxima,one in the shallow water and the other at depth,and separated by a layer of minimum at the bottom of the thermocline.Further analysis shows that this two-segmented vertical transport is attributed to the vertical compensation of subsurface water to the excessive outflow of shallow water and upward push of the dense Luzon Strait overflow,respectively.In the abyssal basin,the vertical transport increases upward from zero at the depth of 3500–4000 m and reaches a maximum of 1.5×10^(6) m^(3)/s at about 1500 m.Deep water upwells mainly from the northeastern and southwestern ends of the abyssal basin and off the continental slopes.To explain the upward velocity arising from slope breaks,a possible mechanism is proposed that an onshore velocity component can be derived from the deep western boundary current above steep slopes under bottom friction.展开更多
A convective cloud transport model, without chemical processes, is developed by joining a set of concentration conservative equations into a two-dimensional, slab-symmetric and fully elastic numerical cloud model, and...A convective cloud transport model, without chemical processes, is developed by joining a set of concentration conservative equations into a two-dimensional, slab-symmetric and fully elastic numerical cloud model, and a numerical experiment is completed to simulate the vertical transport of ground-borne, inert gaseous pollutant by deepthunderstorm. The simulation shows that deep convective storm can very effectively transport high concentrated pollutant gas from PBL upward to the upper troposphere in 30 to 40 minutes, where the pollutant spreads laterally outward with strong anvil outflow, forming an extensive high concentration area. Meanwhile, relatively low concentration areas are formed in PBL both below and beside the cloud, mainly caused by dynamic pumping effect and sub-cloud downdraft flow. About 80% of the pollutant gas transported to the upper troposphere is from the layer below 1.5 km AGL (above ground level).展开更多
A simulation experiment on vertical transport of herbicide atrazine (2 chloro 4 ethylamino 6 isopropylamino s triazine) in soil column was conducted using lysimeter system. The atrazine concentrations in leachi...A simulation experiment on vertical transport of herbicide atrazine (2 chloro 4 ethylamino 6 isopropylamino s triazine) in soil column was conducted using lysimeter system. The atrazine concentrations in leaching water and soil samples in column at 8 layers with 10 cm thick of each layer were detected by high performance liquid chromatography. The results show total atrazine amount in leaching water increases nonlinearly with the leaching time and the herbicide application rate, and the atrazine concentrations in column soil decrease with the vertical depth after water leaching. The distribution of atrazine mass in the system after 154 days were that among the applied atrazine, 0.3% is out through leaching water, 1% is methanol extractable residues in soil, 46% is methanol nonextractable residues in soil, and 52% is other loss (including volatilization and degradation). The study indicates movement of atrazine in agriculture soil may not only have relation to the properties of herbicide, but also to the herbicide application history.展开更多
A 2D vertical(2DV) numerical model,without σ-coordinate transformation in the vertical direction,is developed for the simulation of flow and sediment transport in open channels.In the model,time-averaged Reynolds equ...A 2D vertical(2DV) numerical model,without σ-coordinate transformation in the vertical direction,is developed for the simulation of flow and sediment transport in open channels.In the model,time-averaged Reynolds equations are closed by the k-ε nonlinear turbulence model.The modified YoungsVOF method is introduced to capture free surface dynamics,and the free surface slope is simulated using the ELVIRA method.Based on the power-law scheme,the k-ε model and the suspended-load transport model are solved numerically with an implicit scheme applied in the vertical plane and an explicit scheme applied in the horizontal plane.Bedload transport is modeled using the Euler-WENO scheme,and the grid-closing skill is adopted to deal with the moving channel bed boundary.Verification of the model using laboratory data shows that the model is able to adequately simulate flow and sediment transport in open channels,and is a good starting point for the study of sediment transport dynamics in strong nonlinear flow scenarios.展开更多
Based on the former research work of the authors,the resistance of differentsolid particle suspension flow in a vertical pipe is analysed,and investigatedexperimentally.The applicable formulas of pressure drop are pre...Based on the former research work of the authors,the resistance of differentsolid particle suspension flow in a vertical pipe is analysed,and investigatedexperimentally.The applicable formulas of pressure drop are presented.Two types of par-ticles,talcum powder and glass beads,are convcyed in the test which has been carried outat various air vclocities of 10 to 28 m/s and at the ratio of solids-air mass flow rateranged from 0 to 2.The experimental results show a good agreement with the calculatedones.展开更多
基金financially supported by the Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City(Grant No.520LH052)the National Natural Science Foundation of China(Grant No.51909164).
文摘Deepsea mining has been proposed since the 1960s to alleviate the lack of resources on land.Vertical hydraulic transport of collected ores from the seabed to the sea surface is considered the most promising method for industrial applications.In the present study,an indoor model test of the vertical hydraulic transport of particles was conducted.A noncontact optical method has been proposed to measure the local characteristics of the particles inside a vertical pipe,including the local concentration and particle velocity.The hydraulic gradient of ore transport was evaluated with various particle size distributions,particle densities,feeding concentrations and mixture flow velocities.During transport,the local concentration is larger than the feeding concentration,whereas the particle velocity is less than the mixture velocity.The qualitative effects of the local concentration and local fluid velocity on the particle velocity and slip velocity were investigated.The local fluid velocity contributes significantly to particle velocity and slip velocity,whereas the effect of the local concentration is marginal.A higher feeding concentration and mixture flow velocity result in an increased hydraulic gradient.The effect of the particle size gradation is slight,whereas the particle density plays a crucial role in the transport.
文摘Gravity-1 was the world's first carrier rocket to adopt the sea-based “three vertical” testing launch mode. This article introduces the overall layout of the launch site and the workflow of rocket testing and launch for its maiden flight mission. The process of vertical assembly, vertical testing, vertical transportation, and sea-based hot launches are explained. Additionally, it provides an outlook on the improved “three vertical” testing and launch mode for future missions, such as land-based launches, rapid launches, and remote sea launches.
基金The National Natural Science Foundation of China under contract Nos 41676022,41630970 and 41521005the National Programme on Global Change and Air-Sea Interaction under contract No.GASI-IPOVAI-04+1 种基金the Open Project Program of State Key Laboratory of Tropical Oceanography under contract No.LTOZZ1801the Instrument Developing Project of the Chinese Academy of Sciences under contract No.YZ201432
文摘An integrated analysis of internal solitary wave(ISW) observations obtained from two moorings over the continental slope in the northern South China Sea(SCS) leads to an assessment of the vertical heat transport of the ISWs. The clusters of ISW packets are phase-locked to the fortnightly cycle of the semidiurnal tide. The ISWs appear during large semidiurnal tides, and there is a period of 5–6 d when no ISWs are observed. The effect of the ISWs on the continental slope heat budget is observed. The ISWs can modify a local temperature field in which the temperature in the upper layer can be changed by O(100) °C after the ISWs passed the mooring. Both ISWinduced diffusion and ISW-induced advection contribute to the temperature variation. The estimates imply an average vertical heat flux of 0.01 to 0.1 MW/m^2 in the ISWs in the upper 500 m of the water column. The vertical heat transport ranges from 0.56 to 2.83 GJ/m^2 with a mean value of 1.63 GJ/m^2. The observations suggest that the vertical heat transport is proportional to the maximum vertical displacement.
基金The National Key Research and Development Program of China under contract No.2019YFC1408400the National Natural Science Foundation of China under contract Nos 41876029,41821004 and 41776042.
文摘Deep water in the South China Sea is renewed by the cold and dense Luzon Strait overflow.However,from where and how the deep water upwells is poorly understood yet.Based on the Hybrid Coordinate Ocean Model reanalysis data,vertical velocity is derived to answer these questions.Domain-integrated vertical velocity is of two maxima,one in the shallow water and the other at depth,and separated by a layer of minimum at the bottom of the thermocline.Further analysis shows that this two-segmented vertical transport is attributed to the vertical compensation of subsurface water to the excessive outflow of shallow water and upward push of the dense Luzon Strait overflow,respectively.In the abyssal basin,the vertical transport increases upward from zero at the depth of 3500–4000 m and reaches a maximum of 1.5×10^(6) m^(3)/s at about 1500 m.Deep water upwells mainly from the northeastern and southwestern ends of the abyssal basin and off the continental slopes.To explain the upward velocity arising from slope breaks,a possible mechanism is proposed that an onshore velocity component can be derived from the deep western boundary current above steep slopes under bottom friction.
基金This Project is supported by the National Natural Science Foundation of China.
文摘A convective cloud transport model, without chemical processes, is developed by joining a set of concentration conservative equations into a two-dimensional, slab-symmetric and fully elastic numerical cloud model, and a numerical experiment is completed to simulate the vertical transport of ground-borne, inert gaseous pollutant by deepthunderstorm. The simulation shows that deep convective storm can very effectively transport high concentrated pollutant gas from PBL upward to the upper troposphere in 30 to 40 minutes, where the pollutant spreads laterally outward with strong anvil outflow, forming an extensive high concentration area. Meanwhile, relatively low concentration areas are formed in PBL both below and beside the cloud, mainly caused by dynamic pumping effect and sub-cloud downdraft flow. About 80% of the pollutant gas transported to the upper troposphere is from the layer below 1.5 km AGL (above ground level).
基金Foundationitem :theNationalNaturalSciencesFoundationofChina (No .2 97770 2 6)andtheMajorProjectFoundationoftheChineseAcademyof
文摘A simulation experiment on vertical transport of herbicide atrazine (2 chloro 4 ethylamino 6 isopropylamino s triazine) in soil column was conducted using lysimeter system. The atrazine concentrations in leaching water and soil samples in column at 8 layers with 10 cm thick of each layer were detected by high performance liquid chromatography. The results show total atrazine amount in leaching water increases nonlinearly with the leaching time and the herbicide application rate, and the atrazine concentrations in column soil decrease with the vertical depth after water leaching. The distribution of atrazine mass in the system after 154 days were that among the applied atrazine, 0.3% is out through leaching water, 1% is methanol extractable residues in soil, 46% is methanol nonextractable residues in soil, and 52% is other loss (including volatilization and degradation). The study indicates movement of atrazine in agriculture soil may not only have relation to the properties of herbicide, but also to the herbicide application history.
基金Supported by the National Natural Science Foundation of China(Nos.51579036,51579030)the Fundamental Research Funds for the Central Universities of China(No.DUT14YQ108)
文摘A 2D vertical(2DV) numerical model,without σ-coordinate transformation in the vertical direction,is developed for the simulation of flow and sediment transport in open channels.In the model,time-averaged Reynolds equations are closed by the k-ε nonlinear turbulence model.The modified YoungsVOF method is introduced to capture free surface dynamics,and the free surface slope is simulated using the ELVIRA method.Based on the power-law scheme,the k-ε model and the suspended-load transport model are solved numerically with an implicit scheme applied in the vertical plane and an explicit scheme applied in the horizontal plane.Bedload transport is modeled using the Euler-WENO scheme,and the grid-closing skill is adopted to deal with the moving channel bed boundary.Verification of the model using laboratory data shows that the model is able to adequately simulate flow and sediment transport in open channels,and is a good starting point for the study of sediment transport dynamics in strong nonlinear flow scenarios.
文摘Based on the former research work of the authors,the resistance of differentsolid particle suspension flow in a vertical pipe is analysed,and investigatedexperimentally.The applicable formulas of pressure drop are presented.Two types of par-ticles,talcum powder and glass beads,are convcyed in the test which has been carried outat various air vclocities of 10 to 28 m/s and at the ratio of solids-air mass flow rateranged from 0 to 2.The experimental results show a good agreement with the calculatedones.
