Drying （conditioning） is an important procedure to prevent hydrate formation during gas pipeline gas-up and to protect pipelines against corrosion. The air-drying method is preferred in offshore gas pipelines pre-co...Drying （conditioning） is an important procedure to prevent hydrate formation during gas pipeline gas-up and to protect pipelines against corrosion. The air-drying method is preferred in offshore gas pipelines pre-commissioning. The air-drying process of gas pipelines commonly includes two steps, air purging and soak test. The mass conservation and the phase equilibrium theory are applied to setting up the mathematical models of air purging, which can be used to simulate dry airflow rate and drying time. Fick diffusion law is applied to setting up the mathematical model of soak test, which can predict the water vapor concentration distribution. The results calculated from the purging model and the soak test model are in good agreement with the experimental data in the DF 1-1 offshore production pipeline conditioning. The models are verified to be available for the air-drying project design of offshore gas pipelines. Some proposals for airdrying engineering and operational procedures are put forward by analyzing the air-drying process of DFI-1 gasexporting pipelines.展开更多
To improve the bioactivity and biocompatibility of titanium implants,a rough/porous tantalum(Ta)coating was firstly prepared on Ti6Al4V substrate by cold spraying.The results indicated that the surface of Ta coating i...To improve the bioactivity and biocompatibility of titanium implants,a rough/porous tantalum(Ta)coating was firstly prepared on Ti6Al4V substrate by cold spraying.The results indicated that the surface of Ta coating is extremely rough with lots of visible holes,because of poor deposition quality.Microstructure and microhardness results showed that different layers appeared in the inner and outer parts of coatings,corresponding to porosity,due to lack of subsequent compaction.The simulated body fluid(SBF)soaking test showed that spherical apatite sediments were mineralized on rough/porous surface in SBF after 2–4 weeks,which demonstrated that the cold sprayed Ta coating had good bioactivity.This was mainly attributed to the rough/porous surface of Ta coating obtained by cold spraying,which is conducive to the heterogeneous nucleation of apatite on it.展开更多
文摘Drying （conditioning） is an important procedure to prevent hydrate formation during gas pipeline gas-up and to protect pipelines against corrosion. The air-drying method is preferred in offshore gas pipelines pre-commissioning. The air-drying process of gas pipelines commonly includes two steps, air purging and soak test. The mass conservation and the phase equilibrium theory are applied to setting up the mathematical models of air purging, which can be used to simulate dry airflow rate and drying time. Fick diffusion law is applied to setting up the mathematical model of soak test, which can predict the water vapor concentration distribution. The results calculated from the purging model and the soak test model are in good agreement with the experimental data in the DF 1-1 offshore production pipeline conditioning. The models are verified to be available for the air-drying project design of offshore gas pipelines. Some proposals for airdrying engineering and operational procedures are put forward by analyzing the air-drying process of DFI-1 gasexporting pipelines.
文摘To improve the bioactivity and biocompatibility of titanium implants,a rough/porous tantalum(Ta)coating was firstly prepared on Ti6Al4V substrate by cold spraying.The results indicated that the surface of Ta coating is extremely rough with lots of visible holes,because of poor deposition quality.Microstructure and microhardness results showed that different layers appeared in the inner and outer parts of coatings,corresponding to porosity,due to lack of subsequent compaction.The simulated body fluid(SBF)soaking test showed that spherical apatite sediments were mineralized on rough/porous surface in SBF after 2–4 weeks,which demonstrated that the cold sprayed Ta coating had good bioactivity.This was mainly attributed to the rough/porous surface of Ta coating obtained by cold spraying,which is conducive to the heterogeneous nucleation of apatite on it.
