Heterotrophic denitrification based on polylactic acid(PLAHD)can remove nitrate effectively,but it is expensive and can't remove phosphate.Autotrophic denitrification based on iron sulfide(ISAD)can simultaneously ...Heterotrophic denitrification based on polylactic acid(PLAHD)can remove nitrate effectively,but it is expensive and can't remove phosphate.Autotrophic denitrification based on iron sulfide(ISAD)can simultaneously remove nitrate and phosphate cost-effectively,but its nitrate rate is slow.So,iron sulfide mineral/polylactic acid mixotrophic biofilter(ISPLAB)was constructed to combine advantages of ISAD and PLAHD.ISPLAB achieved nitrogen and phosphorus removal rates of 98.04%and 94.12%,respectively,at a hydraulic retention time(HRT)of 24 h.The study also revealed that controlling molecular weight(MW)of PLA improved the release of soluble organic matter;adding iron sulfide enhanced the hydrolysis of PLA and precipitated PO_(4)^(3-) of Fe^(2+)/Fe^(3+),thereby facilitated simultaneous nitrogen and phosphorus removal.Microbial community analysis resulted that denitrifying bacterias(Phaeodactylibacter and Methylotenera),sulfur-reducing bacterias(Hyphomicrobium),sulfur-oxidizing bacteria(Denitratisoma),iron-reducing bacteria(Romboutsia)and hydrolyzed bacterias(norank_f_norank_o_1-20 and norank_f_Caldilineaceae)coexisted in the ISPLAB system.Organics and iron sulfide drived the denitrification process in ISPLAB.展开更多
Under the dual effects of aerodynamic heating and high-power electronic equipment heating,the heat sink and power demand of advanced high-speed aircraft have been exponentially rising,which seriously restricts the air...Under the dual effects of aerodynamic heating and high-power electronic equipment heating,the heat sink and power demand of advanced high-speed aircraft have been exponentially rising,which seriously restricts the aircraft performance.To improve system cooling and power supply performance and reduce engine performance loss,a power and thermal management system(PTMS)with high performance,low energy consumption,and light weight urgently needs to be developed.In this paper,three modes of a potential PTMS with different heat sinks and bleed air sources are further discussed to analyze and compare the optimal matching with the flight mission at Mach 1-4.4.The equivalent mass method is used to uniformly assess the costs of the fixed weight,bleed,resistance,etc.as a function of the fuel weight penalty,which is chosen as the optimization objective.The optimization variables consist of the compressor outlet temperature,cooling air flow rate,and fan duct heat exchanger structure size.The results show that the intermediate-stage bleed air and fan duct heat sink are more suitable when the Mach number is less than 2,but the ram air bleed is highly suitable for flight missions at a high Mach number.Especially at Mach 3.4-4.4,the ram air bleed mode can respond to the cooling and power demands with a simple architecture.展开更多
基金supported by the National Key Research and Development Program of China(No.2021YFC3201505-02)Shenzhen Science and Technology Plan Collaborative Innovation Project-Undertake Major National Science and Technology Projects of China(No.CJGJZD2020061710260200).
文摘Heterotrophic denitrification based on polylactic acid(PLAHD)can remove nitrate effectively,but it is expensive and can't remove phosphate.Autotrophic denitrification based on iron sulfide(ISAD)can simultaneously remove nitrate and phosphate cost-effectively,but its nitrate rate is slow.So,iron sulfide mineral/polylactic acid mixotrophic biofilter(ISPLAB)was constructed to combine advantages of ISAD and PLAHD.ISPLAB achieved nitrogen and phosphorus removal rates of 98.04%and 94.12%,respectively,at a hydraulic retention time(HRT)of 24 h.The study also revealed that controlling molecular weight(MW)of PLA improved the release of soluble organic matter;adding iron sulfide enhanced the hydrolysis of PLA and precipitated PO_(4)^(3-) of Fe^(2+)/Fe^(3+),thereby facilitated simultaneous nitrogen and phosphorus removal.Microbial community analysis resulted that denitrifying bacterias(Phaeodactylibacter and Methylotenera),sulfur-reducing bacterias(Hyphomicrobium),sulfur-oxidizing bacteria(Denitratisoma),iron-reducing bacteria(Romboutsia)and hydrolyzed bacterias(norank_f_norank_o_1-20 and norank_f_Caldilineaceae)coexisted in the ISPLAB system.Organics and iron sulfide drived the denitrification process in ISPLAB.
文摘Under the dual effects of aerodynamic heating and high-power electronic equipment heating,the heat sink and power demand of advanced high-speed aircraft have been exponentially rising,which seriously restricts the aircraft performance.To improve system cooling and power supply performance and reduce engine performance loss,a power and thermal management system(PTMS)with high performance,low energy consumption,and light weight urgently needs to be developed.In this paper,three modes of a potential PTMS with different heat sinks and bleed air sources are further discussed to analyze and compare the optimal matching with the flight mission at Mach 1-4.4.The equivalent mass method is used to uniformly assess the costs of the fixed weight,bleed,resistance,etc.as a function of the fuel weight penalty,which is chosen as the optimization objective.The optimization variables consist of the compressor outlet temperature,cooling air flow rate,and fan duct heat exchanger structure size.The results show that the intermediate-stage bleed air and fan duct heat sink are more suitable when the Mach number is less than 2,but the ram air bleed is highly suitable for flight missions at a high Mach number.Especially at Mach 3.4-4.4,the ram air bleed mode can respond to the cooling and power demands with a simple architecture.
