Controllable transportation of bubbles in surfactant or aqueous is very important in daily chemical products,food fermentation,mineral flotation and other fields.However,bubbles are mainly dominated by buoyancy and mo...Controllable transportation of bubbles in surfactant or aqueous is very important in daily chemical products,food fermentation,mineral flotation and other fields.However,bubbles are mainly dominated by buoyancy and move upward in solution,which makes the manipulation of bubbles difficult.Although some progress has been made in controlling underwater bubbles,achieving continuous transportation and collection of underwater bubbles without relying on external forces is still a great challenge.To this end,we bionically designed a flexible polydimethylsiloxane(PDMS)porous surface with dual-Janus characteristics.Namely,a porous PDMS membrane integrating structural gradient and wettability gradient realizes the underwater anti-buoyancy unidirectional transportation of bubbles without external force input,and possesses the capability of underwater gas anti-buoyancy transportation and storage.This work provides inspiration and direction for the development and design of underwater gas transportation and storage devices and provides innovative thinking for the implementation of seabed carbon dioxide storage technology.展开更多
Rectangular pipe jacking or box jacking has become more popular in municipal applications because of its better adaptability to shallow overburdens and its higher structural section utilization than the conventional c...Rectangular pipe jacking or box jacking has become more popular in municipal applications because of its better adaptability to shallow overburdens and its higher structural section utilization than the conventional circular pipe jacking.This case study presents a utility tunnel constructed by using rectangular box jacking in Suzhou,China.The utility tunnel,which has a cross section of 9.1 m in width and 5.5 m in height,was jacked 233.6 m,which is the longest known single jacking length of a rectangular box jacking project in China.The box jacking mainly passed through a silty sand layer with high groundwater levels with a minimum depth of cover of only 3.5 m underneath the Yuanhetang River.In this zone,the structures on the surface are sensitive to external disturbance,thus increasing the challenges of construction.A series of measures were taken during the jacking process,and the project was successfully completed.This paper provides an overview of this project and introduces key techniques in the construction of working shafts as well as in the installation and retrieval of the box jacking machine.In addition,the use of lubrication to reduce friction resistance,navigation and application of an anti-buoyancy slab under the Yuanhetang River,and analyses of soil deformation caused by box jacking are described.展开更多
基金supported by the National Natural Science Foundation of China (22105014,21871020,52303143)the China Postdoctoral Science Foundation (2020M680296,2022T150035,2021TQ0023)+4 种基金the High-level Talent Project of Shenyang Ligong Universitythe Special fund of Basic Scientific Research Expenses for Undergraduate Universities in Liaoning Province (LJ212410144077,LJ212410144072)the Beijing Young Talent Support Programthe 111 Projectthe Fundamental Research Funds for the Central Universities。
文摘Controllable transportation of bubbles in surfactant or aqueous is very important in daily chemical products,food fermentation,mineral flotation and other fields.However,bubbles are mainly dominated by buoyancy and move upward in solution,which makes the manipulation of bubbles difficult.Although some progress has been made in controlling underwater bubbles,achieving continuous transportation and collection of underwater bubbles without relying on external forces is still a great challenge.To this end,we bionically designed a flexible polydimethylsiloxane(PDMS)porous surface with dual-Janus characteristics.Namely,a porous PDMS membrane integrating structural gradient and wettability gradient realizes the underwater anti-buoyancy unidirectional transportation of bubbles without external force input,and possesses the capability of underwater gas anti-buoyancy transportation and storage.This work provides inspiration and direction for the development and design of underwater gas transportation and storage devices and provides innovative thinking for the implementation of seabed carbon dioxide storage technology.
文摘Rectangular pipe jacking or box jacking has become more popular in municipal applications because of its better adaptability to shallow overburdens and its higher structural section utilization than the conventional circular pipe jacking.This case study presents a utility tunnel constructed by using rectangular box jacking in Suzhou,China.The utility tunnel,which has a cross section of 9.1 m in width and 5.5 m in height,was jacked 233.6 m,which is the longest known single jacking length of a rectangular box jacking project in China.The box jacking mainly passed through a silty sand layer with high groundwater levels with a minimum depth of cover of only 3.5 m underneath the Yuanhetang River.In this zone,the structures on the surface are sensitive to external disturbance,thus increasing the challenges of construction.A series of measures were taken during the jacking process,and the project was successfully completed.This paper provides an overview of this project and introduces key techniques in the construction of working shafts as well as in the installation and retrieval of the box jacking machine.In addition,the use of lubrication to reduce friction resistance,navigation and application of an anti-buoyancy slab under the Yuanhetang River,and analyses of soil deformation caused by box jacking are described.
