Computational fluid dynamics( CFD) is used to investigate a new type of two-chamber natural gas distributor,which has a natural gas inlet and nine nozzle outlets. The uniformity at the outlet of distributor is practic...Computational fluid dynamics( CFD) is used to investigate a new type of two-chamber natural gas distributor,which has a natural gas inlet and nine nozzle outlets. The uniformity at the outlet of distributor is practice proven to have significant degree influence on its comprehensive performance. To improve the uniformity at the nozzles of the gas distributor,CFD modeling with the RNG k-ε turbulence model is undertaken to understand the mass flow rate of nozzles with reference to different length of chambers and the most optimal length is obtained. The internal flow pattern of the natural gas distributor is analyzed. It is found that the local maximum deviation of the nozzle outflow rate increases with the increase of chambers length when the length is more than 64 mm. The results provide useful suggestions for the optimal design of two-chamber natural gas distributor.展开更多
BACKGROUND Single atrium with single ventricle,or a two-chambered heart,is an extremely rare congenital malformation.Few cases with two-chambered heart surviving to adulthood have been reported.CASE SUMMARY We reporte...BACKGROUND Single atrium with single ventricle,or a two-chambered heart,is an extremely rare congenital malformation.Few cases with two-chambered heart surviving to adulthood have been reported.CASE SUMMARY We reported an adult female patient with a two-chambered heart and situs inversus totalis accompanied by multiple pregnancies and abortions.Magnetic resonance imaging detected a two-chambered heart.B-ultrasound-guided uterine aspiration was performed to absorb 8 g and 10 g of organized villus and decidual tissues,respectively,with a small amount of bleeding.Postoperatively,cyanosis and fatigue-induced shortness of breath were gradually relieved.The patient has currently outlived all similar cases reported so far.CONCLUSION Hemodynamic changes in pregnant women with two-chambered heart impaired cardiac function,responsible for hypoperfusion and miscarriage.展开更多
Fiber screen fractionation of recycled old corrugated container(OCC)pulp and subsequent targeted processing of each fraction can lead to higher fiber quality,more uniform pulp,and increased handsheet strength and surf...Fiber screen fractionation of recycled old corrugated container(OCC)pulp and subsequent targeted processing of each fraction can lead to higher fiber quality,more uniform pulp,and increased handsheet strength and surface smoothness.This pilot-scale study evaluates the benefits of fiber fractionation using a pressure screen prior to low consistency(LC)refining.A 0.81-mm smooth holed screen cylinder is utilized,and two refiner plate patterns are adopted(wide 0.99 km/rev BEL and interim 2.01 km/rev BEL).Here,LC-refined reject fractions are mixed with the created microfibrillated cellulose(MFC),and the mixed pulp and paper qualities are compared with no-MFC OCC pulps.The results indicate that the highest tensile strength of the handsheet is obtained by the addition of MFC to the fractionated refined OCC pulp compared to the unfractionated refined OCC and primary OCC pulps at a given specific energy.Furthermore,the experimental approach adopted in this study can be used to optimize recycled OCC pulping systems.Overall,the results indicate that fractionated LC refining plus MFC addition provides higher pulp and paper qualities and the potential for saving energy to reach the desired tensile strength of the OCC pulp.展开更多
基金Sponsored by the Beijing Key Lab of Heating,Gas Supply,Ventilating and Air Conditioning Engineering(Grant No.NR2013K04)the Higher School Science and Technology Development Fund of Tianjin(Grant No.20130909)
文摘Computational fluid dynamics( CFD) is used to investigate a new type of two-chamber natural gas distributor,which has a natural gas inlet and nine nozzle outlets. The uniformity at the outlet of distributor is practice proven to have significant degree influence on its comprehensive performance. To improve the uniformity at the nozzles of the gas distributor,CFD modeling with the RNG k-ε turbulence model is undertaken to understand the mass flow rate of nozzles with reference to different length of chambers and the most optimal length is obtained. The internal flow pattern of the natural gas distributor is analyzed. It is found that the local maximum deviation of the nozzle outflow rate increases with the increase of chambers length when the length is more than 64 mm. The results provide useful suggestions for the optimal design of two-chamber natural gas distributor.
基金Supported by Chinese Ministry of Education(No.2020-39)Zunyi Science and Technology Project,No.Zunshi Kehe HZ(2020)246.
文摘BACKGROUND Single atrium with single ventricle,or a two-chambered heart,is an extremely rare congenital malformation.Few cases with two-chambered heart surviving to adulthood have been reported.CASE SUMMARY We reported an adult female patient with a two-chambered heart and situs inversus totalis accompanied by multiple pregnancies and abortions.Magnetic resonance imaging detected a two-chambered heart.B-ultrasound-guided uterine aspiration was performed to absorb 8 g and 10 g of organized villus and decidual tissues,respectively,with a small amount of bleeding.Postoperatively,cyanosis and fatigue-induced shortness of breath were gradually relieved.The patient has currently outlived all similar cases reported so far.CONCLUSION Hemodynamic changes in pregnant women with two-chambered heart impaired cardiac function,responsible for hypoperfusion and miscarriage.
基金supported by the Beijing Natural Science Foundation(2234090).
文摘Fiber screen fractionation of recycled old corrugated container(OCC)pulp and subsequent targeted processing of each fraction can lead to higher fiber quality,more uniform pulp,and increased handsheet strength and surface smoothness.This pilot-scale study evaluates the benefits of fiber fractionation using a pressure screen prior to low consistency(LC)refining.A 0.81-mm smooth holed screen cylinder is utilized,and two refiner plate patterns are adopted(wide 0.99 km/rev BEL and interim 2.01 km/rev BEL).Here,LC-refined reject fractions are mixed with the created microfibrillated cellulose(MFC),and the mixed pulp and paper qualities are compared with no-MFC OCC pulps.The results indicate that the highest tensile strength of the handsheet is obtained by the addition of MFC to the fractionated refined OCC pulp compared to the unfractionated refined OCC and primary OCC pulps at a given specific energy.Furthermore,the experimental approach adopted in this study can be used to optimize recycled OCC pulping systems.Overall,the results indicate that fractionated LC refining plus MFC addition provides higher pulp and paper qualities and the potential for saving energy to reach the desired tensile strength of the OCC pulp.
