A new membrane finite element method for modeling fluid flow in a porous medium is presented in order to quickly and accurately simulate the geo-membrane fabric used in civil engineering. It is based on discontinuous ...A new membrane finite element method for modeling fluid flow in a porous medium is presented in order to quickly and accurately simulate the geo-membrane fabric used in civil engineering. It is based on discontinuous finite element theory, and can be easily coupled with the normal Galerkin finite element method. Based on the saturated seepage equation, the element coefficient matrix of the membrane element method is derived, and a geometric transform relation for the membrane element between a global coordinate system and a local coordinate system is obtained. A method for the determination of the fluid flux conductivity[0] of the membrane element is presented. This method provides a basis for determining discontinuous parameters in discontinuous finite element theory. An anti-seepage problem regarding the foundation of a building is analyzed by coupling the membrane finite element method with the normal Galerkin finite element method. The analysis results demonstrate the utility and superiority of the membrane finite element method in fluid flow analysis of a porous medium.展开更多
Membrane distillation(MD)is a promising alternative desalination technology,but the hydrophobic membrane cannot intercept volatile organic compounds(VOCs),resulting in aggravation in the quality of permeate.In term of...Membrane distillation(MD)is a promising alternative desalination technology,but the hydrophobic membrane cannot intercept volatile organic compounds(VOCs),resulting in aggravation in the quality of permeate.In term of this,electro-Fenton(EF)was coupled with sweeping gas membrane distillation(SGMD)in a more efficient way to construct an advanced oxidation barrier at the gas-liquid interface,so that the VOCs could be trapped in this layer to guarantee the water quality of the distillate.During the so-called EF-MD process,an interfacial interception barrier containing hydroxyl radical formed on the hydrophobic membrane surface.It contributed to the high phenol rejection of 90.2% with the permeate phenol concentration lower than 1.50 mg/L.Effective interceptions can be achieved in a wide temperature range,even though the permeate flux of phenol was also intensified.The EF-MD system was robust to high salinity and could electrochemically regenerate ferrous ions,which endowed the long-term stability of the system.This novel EF-MD configuration proposed a valuable strategy to intercept VOCs in MD and will broaden the application of MD in hypersaline wastewater treatment.展开更多
Members of the Pseudomonas family are commonly found in nature, some species are pathogenic for humans, as well as being resistant to multiple disinfectants. Various studies have revealed that benzalkonium chloride (B...Members of the Pseudomonas family are commonly found in nature, some species are pathogenic for humans, as well as being resistant to multiple disinfectants. Various studies have revealed that benzalkonium chloride (BKC) has an inhibitory effect on many bacteria but it has no significant effect on Pseudomonas aeruginosa. Cetrimide agar medium is recommended for the isolation and enumeration of Ps. aeruginosa in food and environmental samples. However, there are claims that for some food factories and in particular the bottled water industry, the selectivity of this medium is not sufficient. The aim of the current research is the creation of a more selective medium for Ps. aeruginosa with BKC. A total of 28 isolates were isolated with Cetrimide agar from raw water samples and identified using biochemical tests and commercial identification kits. All the bacteria were inoculated in Cetrimide agar plates containing 0 - 625 μg/mL BKC. The Petri dishes were incubated at 37°C and 42°C for 24 h. The results showed that 375 μg/mL BKC was sufficient to suppress Burk. pseudomallei at both incubation temperatures. Ps. fluorescens-35 could not grow at 42°C at any concentration, including the control, and was suppressed at 500 μg/mL BKC. All the Ps. aeruginosa isolates and control strain were grown at both incubation temperatures at 375 μg/mL BKC concentration. In conclusion, the analysis of Ps. aeruginosa showed that the growth of accompanying flora may be suppressed by adding 375-μg/mL BKC into Cetrimide agar and incubating at an elevated temperature of 42°C.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 50779012)
文摘A new membrane finite element method for modeling fluid flow in a porous medium is presented in order to quickly and accurately simulate the geo-membrane fabric used in civil engineering. It is based on discontinuous finite element theory, and can be easily coupled with the normal Galerkin finite element method. Based on the saturated seepage equation, the element coefficient matrix of the membrane element method is derived, and a geometric transform relation for the membrane element between a global coordinate system and a local coordinate system is obtained. A method for the determination of the fluid flux conductivity[0] of the membrane element is presented. This method provides a basis for determining discontinuous parameters in discontinuous finite element theory. An anti-seepage problem regarding the foundation of a building is analyzed by coupling the membrane finite element method with the normal Galerkin finite element method. The analysis results demonstrate the utility and superiority of the membrane finite element method in fluid flow analysis of a porous medium.
基金supported by the National Natural Science Foundation of China(Nos.52200111,51978651,and 51878049)the China Postdoctoral Science Foundation(No.2021M703407)the special fund from the State Key Joint Laboratory of Environment Simulation and Pollution Control(Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences(No.21Z01ESPCR)。
文摘Membrane distillation(MD)is a promising alternative desalination technology,but the hydrophobic membrane cannot intercept volatile organic compounds(VOCs),resulting in aggravation in the quality of permeate.In term of this,electro-Fenton(EF)was coupled with sweeping gas membrane distillation(SGMD)in a more efficient way to construct an advanced oxidation barrier at the gas-liquid interface,so that the VOCs could be trapped in this layer to guarantee the water quality of the distillate.During the so-called EF-MD process,an interfacial interception barrier containing hydroxyl radical formed on the hydrophobic membrane surface.It contributed to the high phenol rejection of 90.2% with the permeate phenol concentration lower than 1.50 mg/L.Effective interceptions can be achieved in a wide temperature range,even though the permeate flux of phenol was also intensified.The EF-MD system was robust to high salinity and could electrochemically regenerate ferrous ions,which endowed the long-term stability of the system.This novel EF-MD configuration proposed a valuable strategy to intercept VOCs in MD and will broaden the application of MD in hypersaline wastewater treatment.
文摘Members of the Pseudomonas family are commonly found in nature, some species are pathogenic for humans, as well as being resistant to multiple disinfectants. Various studies have revealed that benzalkonium chloride (BKC) has an inhibitory effect on many bacteria but it has no significant effect on Pseudomonas aeruginosa. Cetrimide agar medium is recommended for the isolation and enumeration of Ps. aeruginosa in food and environmental samples. However, there are claims that for some food factories and in particular the bottled water industry, the selectivity of this medium is not sufficient. The aim of the current research is the creation of a more selective medium for Ps. aeruginosa with BKC. A total of 28 isolates were isolated with Cetrimide agar from raw water samples and identified using biochemical tests and commercial identification kits. All the bacteria were inoculated in Cetrimide agar plates containing 0 - 625 μg/mL BKC. The Petri dishes were incubated at 37°C and 42°C for 24 h. The results showed that 375 μg/mL BKC was sufficient to suppress Burk. pseudomallei at both incubation temperatures. Ps. fluorescens-35 could not grow at 42°C at any concentration, including the control, and was suppressed at 500 μg/mL BKC. All the Ps. aeruginosa isolates and control strain were grown at both incubation temperatures at 375 μg/mL BKC concentration. In conclusion, the analysis of Ps. aeruginosa showed that the growth of accompanying flora may be suppressed by adding 375-μg/mL BKC into Cetrimide agar and incubating at an elevated temperature of 42°C.
