In this study, a poly（ether block amide） （Pebax 1657） composite membrane applied for COa capture was prepared by coating Pebax 1657 solution on polyacrylonitrile （PAN） ultrafiltration membrane. Ethanol/water mix...In this study, a poly（ether block amide） （Pebax 1657） composite membrane applied for COa capture was prepared by coating Pebax 1657 solution on polyacrylonitrile （PAN） ultrafiltration membrane. Ethanol/water mixture was used as the solvent of Pebax and the effects of ethanol/water mass ratios and Pebax concentration on the permeation properties of composite membrane were studied. To enhance the com- posite membrane permeance, the gutter layer, made from reactive amino silicone crosslinking with potydimethylsiloxane （PDMS）, was de- signed. The influence of crosslinldng degree of the gutter layer on membrane performance was investigated. As a result, a Pebardamino- PDMS/PAN multilayer membrane with hexane resistance was developed, showing CO2 permeance of 350 GPU and CO2/N2 selectivity over 50. The blend of polyethylene glycol dimethyl ether （PEG-DME） with Pebax as coating material was studied to further improve the membrane performance. After being combined with PEG-DME additive, CO2 permeance of the final Pebax-PEG-DME/amino-PDMS/PAN composite membrane reached 400 GPU above with CO2/Na selectivity over 65.展开更多
Steel mesh is used as a passive skin confinement medium to supplement the active support provided by rock bolts for roof and rib control in underground coal mines. Thin spray-on liners(TSL) are believed to have the po...Steel mesh is used as a passive skin confinement medium to supplement the active support provided by rock bolts for roof and rib control in underground coal mines. Thin spray-on liners(TSL) are believed to have the potential to take the place of steel mesh as the skin confinement medium in underground mines.To confirm this belief, large scale laboratory experiments were conducted to compare the behaviour of welded steel mesh and a TSL, when used in conjunction with rock bolts, in reinforcing strata with weak bedding planes and strata prone to guttering, two common rock conditions which exist in coal mines. It was found that while the peak load taken by the simulated rock mass with weak bedding planes acting as the control sample(no skin confinement) was 2494 kN, the corresponding value of the sample with 5 mm thick TSL reinforcement reached 2856 kN. The peak load of the steel mesh reinforced sample was only2321 kN, but this was attributed to the fact that one of the rock bolts broke during the test. The TSL reinforced sample had a similar post-yield behaviour as the steel mesh reinforced one. The results of the large scale guttering test indicated that a TSL is better than steel mesh in restricting rock movement and thus inhibiting the formation of gutters in the roof.展开更多
文摘In this study, a poly（ether block amide） （Pebax 1657） composite membrane applied for COa capture was prepared by coating Pebax 1657 solution on polyacrylonitrile （PAN） ultrafiltration membrane. Ethanol/water mixture was used as the solvent of Pebax and the effects of ethanol/water mass ratios and Pebax concentration on the permeation properties of composite membrane were studied. To enhance the com- posite membrane permeance, the gutter layer, made from reactive amino silicone crosslinking with potydimethylsiloxane （PDMS）, was de- signed. The influence of crosslinldng degree of the gutter layer on membrane performance was investigated. As a result, a Pebardamino- PDMS/PAN multilayer membrane with hexane resistance was developed, showing CO2 permeance of 350 GPU and CO2/N2 selectivity over 50. The blend of polyethylene glycol dimethyl ether （PEG-DME） with Pebax as coating material was studied to further improve the membrane performance. After being combined with PEG-DME additive, CO2 permeance of the final Pebax-PEG-DME/amino-PDMS/PAN composite membrane reached 400 GPU above with CO2/Na selectivity over 65.
文摘Steel mesh is used as a passive skin confinement medium to supplement the active support provided by rock bolts for roof and rib control in underground coal mines. Thin spray-on liners(TSL) are believed to have the potential to take the place of steel mesh as the skin confinement medium in underground mines.To confirm this belief, large scale laboratory experiments were conducted to compare the behaviour of welded steel mesh and a TSL, when used in conjunction with rock bolts, in reinforcing strata with weak bedding planes and strata prone to guttering, two common rock conditions which exist in coal mines. It was found that while the peak load taken by the simulated rock mass with weak bedding planes acting as the control sample(no skin confinement) was 2494 kN, the corresponding value of the sample with 5 mm thick TSL reinforcement reached 2856 kN. The peak load of the steel mesh reinforced sample was only2321 kN, but this was attributed to the fact that one of the rock bolts broke during the test. The TSL reinforced sample had a similar post-yield behaviour as the steel mesh reinforced one. The results of the large scale guttering test indicated that a TSL is better than steel mesh in restricting rock movement and thus inhibiting the formation of gutters in the roof.
