To solve the problem of low efficiency of NO_(x)emission reduction in self-reflux burners,this study is based on the concept of coordinated control of self-reflux burner structural and thermal parameters.After complet...To solve the problem of low efficiency of NO_(x)emission reduction in self-reflux burners,this study is based on the concept of coordinated control of self-reflux burner structural and thermal parameters.After completing the structural design and optimization of thermal parameters,we continue to adjust the two key structural parameters:the nozzle axis distance and the length of the cylindrical section,to minimize NO_(x)emissions.These are the two parameters that chiefly affect the mixing of flue gas and fuel gas.The results show that increasing nozzle axis distance can delay the mixing of gas and air and create a more uniform oxygen concentration field for the combustion process.The maximum combustion temperature is reduced from 1973.65 K to 1935.88 K and the volume fraction of NO_(x)in the flue gas is reduced from 188.08×10^(–6)to 143.47×10^(–6).However,compared with the nozzle axis distance,the length of the cylindrical section of the burner has little effect on the mixing of the flow field.Under different cylindrical section lengths,the maximum combustion temperature does not change more than 3 K,and the volume fraction of NO_(x)in the flue gas changes within 5×10~(–6).展开更多
Decentralized treatment of wastewater in rural areas usually has several challenges,which include large fluctuations in pollutant concentration and water quantity,complicated operation and maintenance of conventional ...Decentralized treatment of wastewater in rural areas usually has several challenges,which include large fluctuations in pollutant concentration and water quantity,complicated operation and maintenance of conventional biochemical treatment equipment,resulting in poor stability and a low compliance rate of the wastewater treatment process.In order to solve the above problems,a new integration reactor is designed,which uses gravity and aeration tail gas self-reflux technology to realize the reflux of sludge and the nitrification liquid,respectively.The feasibility and operation characteristics of its application for decentralized wastewater treatment in rural areas are explored.The results demonstrated that,under constant influent,the device showed strong tolerance to the shock of pollutant load.The chemical oxygen demand,NH_(4)^(+)-N,total nitrogen and total phosphorus fluctuated in the ranges of 95–715 mg/L,7.6–38.5 mg/L,9.32–40.3 mg/L and 0.84–4.9 mg/L,respectively.The corresponding effluent compliance rates were 82.1%,92.8%,96.4%and 96.3%,respectively.When the wastewater discharge was non-constant and the maximum single-day Qmax/Qmin reached 5,all indicators of the effluent met the relevant discharge standard.The integrated device also demonstrated high phosphorus enrichment levels in its anaerobic zone;the concentration of phosphorus reached a maximum of 26.9 mg/L,which created a good environment for phosphorus removal.The microbial community analysis showed that sludge digestion,denitrification,and phosphorus-accumulating bacteria all played an important role in pollutant treatment.展开更多
基金supported by the Fundamental Research Funds for the National Natural Science Foundation of China(No.52006008,62033014)Guangdong Basic and Applied Basic Research Foundation(2019A1515110743)+2 种基金Scientific and Technological Innovation Foundation of Shunde Graduate School of USTB(BK20BE010)Guangdong University Research Findings Commercialization Center(2020JNHB06)the Central Universities of China(FRF-TP-18-074A1,FRF-BD-20-09A)。
文摘To solve the problem of low efficiency of NO_(x)emission reduction in self-reflux burners,this study is based on the concept of coordinated control of self-reflux burner structural and thermal parameters.After completing the structural design and optimization of thermal parameters,we continue to adjust the two key structural parameters:the nozzle axis distance and the length of the cylindrical section,to minimize NO_(x)emissions.These are the two parameters that chiefly affect the mixing of flue gas and fuel gas.The results show that increasing nozzle axis distance can delay the mixing of gas and air and create a more uniform oxygen concentration field for the combustion process.The maximum combustion temperature is reduced from 1973.65 K to 1935.88 K and the volume fraction of NO_(x)in the flue gas is reduced from 188.08×10^(–6)to 143.47×10^(–6).However,compared with the nozzle axis distance,the length of the cylindrical section of the burner has little effect on the mixing of the flow field.Under different cylindrical section lengths,the maximum combustion temperature does not change more than 3 K,and the volume fraction of NO_(x)in the flue gas changes within 5×10~(–6).
文摘目的评价自我管理干预对胃食管反流病(gastro-esophageal reflux disease,GERD)患者健康的影响。方法2016年6月,电子检索Cochrane Library(1990-2016)、JBI Library、Pubmed(1990-2016)、护理数据库(1990-2016)、EMbase(1990-2016)、中国学术期刊网络出版总库(1994-2016)、万方数据库、中国生物医学文献数据库(1990-2016),纳入关于GERD的中、英文公开发表的随机对照试验(randomized control trials,RCT)。采用RevMan5.1软件进行数据合并分析,不能进行数据合并则采用描述性分析。结果最终纳入5篇研究,共611名患者。由于异质性较大,不强制进行合并,定性分析结果显示,自我管理干预能促进患者的自我管理行为,提高疾病相关知识水平。结论自我管理干预能够改善患者的反流症状、促进健康行为,但对患者健康相关生活质量(health-related quality of life,HRQOL)无明显改善作用。
基金supported by the Natural Science Foundation of China(No.51938010)the National&Local Joint Engineering Laboratory for Municipal Sewage Resource Utilization Technology,Suzhou University of Science and Technology(No.2019KF04)+1 种基金the Jiangsu Provincial Key Laboratory of Environmental Science and Engineering(No.JSHJZDSYS-202004)the Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment(No.XTCXSZ2022-1).
文摘Decentralized treatment of wastewater in rural areas usually has several challenges,which include large fluctuations in pollutant concentration and water quantity,complicated operation and maintenance of conventional biochemical treatment equipment,resulting in poor stability and a low compliance rate of the wastewater treatment process.In order to solve the above problems,a new integration reactor is designed,which uses gravity and aeration tail gas self-reflux technology to realize the reflux of sludge and the nitrification liquid,respectively.The feasibility and operation characteristics of its application for decentralized wastewater treatment in rural areas are explored.The results demonstrated that,under constant influent,the device showed strong tolerance to the shock of pollutant load.The chemical oxygen demand,NH_(4)^(+)-N,total nitrogen and total phosphorus fluctuated in the ranges of 95–715 mg/L,7.6–38.5 mg/L,9.32–40.3 mg/L and 0.84–4.9 mg/L,respectively.The corresponding effluent compliance rates were 82.1%,92.8%,96.4%and 96.3%,respectively.When the wastewater discharge was non-constant and the maximum single-day Qmax/Qmin reached 5,all indicators of the effluent met the relevant discharge standard.The integrated device also demonstrated high phosphorus enrichment levels in its anaerobic zone;the concentration of phosphorus reached a maximum of 26.9 mg/L,which created a good environment for phosphorus removal.The microbial community analysis showed that sludge digestion,denitrification,and phosphorus-accumulating bacteria all played an important role in pollutant treatment.
