This study investigates the photocatalytic degradation of microcystin-LR (MC-LR) under simulated solar light using Pt modified nano-sized tungsten trioxides (Pt/WO3). Photocatalytic activity was higher during the degr...This study investigates the photocatalytic degradation of microcystin-LR (MC-LR) under simulated solar light using Pt modified nano-sized tungsten trioxides (Pt/WO3). Photocatalytic activity was higher during the degradation of MC-LR with Pt/WO 3 than with pure WO 3 or Ti O2 . The catalyst loading greatly affect the degradation performance. The rate of degradation is influenced by the initial pH of the reaction solution. This study also investigates the photocatalytic inactivation of cyanobacteria. The results show that the algal growth was successfully controlled by the Pt/W O 3 . This study suggests Pt/W O 3 photocatalytic oxidation with solar light is a promising treatment for water containing MC-LR.展开更多
China is facing the challenge of many marine environment problems with rapid economic growth. Japan had experienced similar marine environmental pressure during its industrialization and had been facing the problem th...China is facing the challenge of many marine environment problems with rapid economic growth. Japan had experienced similar marine environmental pressure during its industrialization and had been facing the problem through successful environment policy step by step. The paper reviews the lessons and experiences of Japan’s marine environment protection and analyzes the marine environment pollution in China and its causes, taking Shandong province as a case, such as GDP-oriented economic growth, heavy coal assumption, etc. The paper also analyzes the marine industry with focuses on coastal tourism and its relationship with marine environment. Suggestions on polices are provided based on the analysis on China’ marine environment and Japan’s experience.展开更多
The effects of TiO2 photocatalysis on the hydrolysis of protein of waste activated sludge (WAS) and its biodegradability were investigated in this study. After 12-h UV irradiation, the removal ratio of protein by TiO2...The effects of TiO2 photocatalysis on the hydrolysis of protein of waste activated sludge (WAS) and its biodegradability were investigated in this study. After 12-h UV irradiation, the removal ratio of protein by TiO2 photocatalysis reached 98.1%. The optimal condition for photocatalytic degradation of protein is TiO2 dosage of 5.0 mg·L–1 under 2.4 w·m–2 UV light irradiation. TiO2 photocatalysis in comparison with other pretreatments obviously accelerated the hydrolysis of WAS and improved the conversion of total COD (tCOD) to soluble COD (sCOD). The sCOD/tCOD ratio of WAS pretreated by TiO2 photocatalysis, UV photolysis and TiO2 adsorption and that of the control were 92.8%, 32.5%, 18.0% and 16.6%, respectively. TiO2 photocatalytic pretreatment accelerated the biohydrogen production from 10-fold diluted WAS. The bioreactors containing UV photolysis and TiO2 adsorption pretreated WASs and the control reactor require 0.5-d, 0.9-d and 0.7-d start-up period for biohydrogen production, respectively. While the bioreactor containing TiO2 photocatalysis pretreated WAS obtained a hydrogen yield of 0.5 mL-H2/g-VS merely after 0.5-d mesophilic fermentation. The cumulative biohydrogen production from TiO2 photocatalysis pretreated WAS during 4-d mesophilic fermentation reached 11.7 mL-H2/g-VS, which was 1.2 times higher than that from the control. TiO2 photocatalytic pretreatment enhanced the biohydrogen production from WAS via accelerating the hydrolysis of its macromolecular components to smaller molecule weight hydrolysates.展开更多
Electrochemical oxidation of ammonia was studied with an objective to enhance the selectivity of ammonia to nitrogen gas and to remove the by-products in an undivided electrochemical cell, in which various cathodes an...Electrochemical oxidation of ammonia was studied with an objective to enhance the selectivity of ammonia to nitrogen gas and to remove the by-products in an undivided electrochemical cell, in which various cathodes and Ti/RuO 2-Pt anode were assembled. In the present study, anodic oxidation of ammonia and cathodic reduction of by-products were achieved, especially with Cu/Zn as cathode. In the presence of 1.0 g/L NaCl the ammonia-N decreased from 100.0 to 0 after 120 min electrolysis at current density of 30 mA/cm2, and no nitrite was detected in the treated solution. The lowest amount of nitrate was formed with Cu/Zn as cathode during electrolysis due to its high reduction ability. Initial pH range from 7 and 9 and uncontrolled temperature were favorable for electrochemical ammonia oxidation and the ammonia oxidation rates with Cu/Zn cathode was higher than that with Ti and Fe cathode. The reduction rate increased with increasing current density in the range of 5 - 50 mA/cm2. As ammonia could be completely removed by the simultaneous oxidation and reduction in this study, it is suitable for deep treatment of ammonia polluted water.展开更多
Chlorsulfuron (ChS) which is a nonbiodegradable herbicide was effectively removed using an electrochemical method at the Ti/IrO2-Pt anode. The influences of current density, initial ChS concentration, initial solution...Chlorsulfuron (ChS) which is a nonbiodegradable herbicide was effectively removed using an electrochemical method at the Ti/IrO2-Pt anode. The influences of current density, initial ChS concentration, initial solution pH and different NaCl dosages on electrochemical degradation of ChS were investigated. HOCl formed during electrolysis and quickly generated .OH radicals would likely play an important role in the electrochemical degradation of ChS with the presence of NaCl. At current density of 20 mA?cm–2, ChS concentration decreased from 1 mg.L–1 to 0 mg.L–1 after 10 min electrolysis with 0.2 g?L–1 NaCl dosage. It was found that the ChS removal rate increased with increasing current density and the ChS degradation was similar at different initial pH values, which means that Ti/IrO2-Pt anode can be used in a wide pH range. The electrochemical performance of Ti/IrO2-Pt anode for degradation of ChS will not decrease after serviced for a long time. These results reveal that an electrochemical approach would be a novel treatment method for effective and rapid degradation of ChS herbicide from aqueous solution.展开更多
Anaerobic digestion(AD)of waste activated sludge(WAS)is usually limited by the low generation efficiency of methane.Fe(Ⅲ)-loaded chitosan composite(CTS-Fe)have been reported to effectively enhanced the digestion of W...Anaerobic digestion(AD)of waste activated sludge(WAS)is usually limited by the low generation efficiency of methane.Fe(Ⅲ)-loaded chitosan composite(CTS-Fe)have been reported to effectively enhanced the digestion of WAS,but its role in promoting anaerobic sludge digestion remains unclear.In present study,the effects of CTS-Fe on the hydrolysis and methanogenesis stages of WAS anaerobic digestion were investigated.The addition of CTSFe increased methane production potential by 8%-23%under the tested conditions with the addition of 5-20 g/L CTS-Fe.Besides,the results demonstrate that the addition of CTS-Fe could effectively promote the hydrolysis of WAS,evidenced by lower protein or polysaccharides concentration,higher soluble organic carbon in rector adding CTS-Fe,as well as the increased activity of extracellular hydrolase with higher CTS-Fe concentration.Meanwhile,the enrichment of Clostridia abundance(iron-reducing bacteria(IRBs))was observed in CTS-Fe adding reactor(8.9%-13.8%),which was higher than that in the control reactor(7.9%).The observation further suggesting the acceleration of hydrolysis through dissimilatory iron reduction(DIR)process,thus providing abundant substrates for methanogenesis.However,the presence of CTS-Fe was inhibited the acetoclastic and hydrogenotrophic methanogenesis process,which could be ascribed to the Fe(Ⅲ)act as electron acceptor coupled to methane for anaerobic oxidation.Furthermore,coenzyme F420 activity in the CTS-Fe added reactor was 34.9% lower than in the blank,also abundance of microorganisms involved in hydrogenotrophic methanogenesis was decreased.Results from this study could provide theoretical support for the practical applications of CTS-Fe.展开更多
与传统的基于接收信号强度(received signal strength, RSS)的室内Wi-Fi定位方法相比,信道状态信息(channel state information, CSI)包含了信号传输过程中更细粒度和更多样化的物理层信息(如信道中各个子载波的振幅和相位信息),故基于...与传统的基于接收信号强度(received signal strength, RSS)的室内Wi-Fi定位方法相比,信道状态信息(channel state information, CSI)包含了信号传输过程中更细粒度和更多样化的物理层信息(如信道中各个子载波的振幅和相位信息),故基于CSI的室内Wi-Fi定位方法通常具有更高的定位精度.在利用CSI进行定位时,发送端采用正交频分复用(orthogonal frequency division multiplexing,OFDM)技术在多个正交子载波上并行发送数据并在接收端进行解调,但由于异步效应(如载波频率偏差(carrier frequency offset, CFO)、采样时钟频率偏差(sampling frequency offset, SFO)和符号定时偏差(symbol timing offset, STO))的存在,接收端子载波的正交性难以得到保证,于是,基于CSI的室内Wi-Fi定位方法的性能会因为符号间干扰(inter symbol interference, ISI)和载波间干扰(inter carrier interference, ICI)的影响而下降.对此,本文从频域的角度推导了不同异步效应下的CSI定位误差界以评估基于CSI的室内Wi-Fi定位性能.展开更多
Mineral dust particles play an important role in the formation of secondary inorganic aerosols, which largely contribute to haze pollution in China.During this study, a haze episode(haze days) and a typical haze proce...Mineral dust particles play an important role in the formation of secondary inorganic aerosols, which largely contribute to haze pollution in China.During this study, a haze episode(haze days) and a typical haze process mixed with sandstorm(sandy haze days)were observed in Zhengzhou with a series of high-time-resolution monitoring instruments from November 22 to December 8, 2018.Concentrations of PM10 and crustal elements clearly increased in the sandy haze days.Concentrations of gaseous pollutants, metallic elements emitted from anthropogenic sources, nitrate, and ammonium during sandy haze days were slightly lower than those during the haze days but still obviously higher than those during the non-haze days.The sulfate concentrations, the sulfate fractions in PM2.5,and the sulfur oxidation ratios significantly increased in the sandy haze days.Heterogeneous reactions dominated the conversion of SO2 during the haze and sandy haze days.Enhanced SO2 conversion during the sandy haze days may be attributed to the high concentrations of transition metal ions from the sandstorm when the values of relative humidity(RH) were in 30%–70%, and high O3 at certain time points.Gas-phase NO2 oxidation reactions were the main pathways for nitrate formation.In the sandy haze days,higher nitrogen oxidation ratio(NOR) at daytime may be associated with higher RH and lower temperature than those in the haze days, which facilitate the gas-to-particle partitioning of nitrate;higher NOR values at night may be attributed to the higher O3 concentrations, which promoted the formation of N2O5.展开更多
A lab-scale intermittently aerated sequencing batch reactor（IASBR）was applied to treat anaerobically digested swine wastewater（ADSW）to explore the removal characteristics of veterinary antibiotics.The removal rate...A lab-scale intermittently aerated sequencing batch reactor（IASBR）was applied to treat anaerobically digested swine wastewater（ADSW）to explore the removal characteristics of veterinary antibiotics.The removal rates of 11 veterinary antibiotics in the reactor were investigated under different chemical organic demand（COD）volumetric loadings,solid retention times（SRT）and ratios of COD to total nitrogen（TN）or COD/TN.Both sludge sorption and biodegradation were found to be the major contributors to the removal of veterinary antibiotics.Mass balance analysis revealed that greater than 60%of antibiotics in the influent were biodegraded in the IASBR,whereas averagely 24%were adsorbed by sludge under the condition that sludge sorption gradually reached its equilibrium.Results showed that the removal of antibiotics was greatly influenced by chemical oxygen demand（COD）volumetric loadings,which could achieve up to 85.1%±1.4%at 0.17±0.041 kg COD/m-3/day,while dropped to 75.9%±1.3%and 49.3%±12.1%when COD volumetric loading increased to 0.65±0.032 and1.07±0.073 kg COD/m-3/day,respectively.Tetracyclines,the dominant antibiotics in ADSW,were removed by 87.9%in total at the lowest COD loading,of which 30.4%were contributed by sludge sorption and 57.5%by biodegradation,respectively.In contrast,sulfonamides were removed about 96.2%,almost by biodegradation.Long SRT seemed to have little obvious impact on antibiotics removal,while a shorter SRT of 30–40 day could reduce the accumulated amount of antibiotics and the balanced antibiotics sorption capacity of sludge.Influent COD/TN ratio was found not a key impact factor for veterinary antibiotics removal in this work.展开更多
The microstructural evolution of rapidly solidified（RS） ZK60 powders extruded at 250 C was investigated.It was shown that formation of new ultrafine grains took place through continuous dynamic recrystallization（C...The microstructural evolution of rapidly solidified（RS） ZK60 powders extruded at 250 C was investigated.It was shown that formation of new ultrafine grains took place through continuous dynamic recrystallization（CDRX）,accompanied by the perfect bonding of powders via severe plastic deformation.At a low strain level,a well-defined structure made up of equiaxed and elongated subgrains was developed.Simultaneously,the operation of basal and non-basal dislocation slip led to the formation of low-angle dislocation cells（LADC） within the elongated subgrains.With increasing strain,the number and average misorientation of LADC increased,resulting in fragmentation of original elongation subgrains into a finally homogeneous fine-grained structure.Almost full-recrystallized structure with an average grain size of 0.4 μm was finally evolved after large cumulative strain.The results suggested that structural change was connected with thermal strain,where dislocation activities dominated this process.展开更多
Ammonia has emerged as a promising hydrogen carrier with applications as an energy source in recent years. However, in addition to being toxic, gaseous ammonia is a precursor of secondary inorganic aerosols. The conce...Ammonia has emerged as a promising hydrogen carrier with applications as an energy source in recent years. However, in addition to being toxic, gaseous ammonia is a precursor of secondary inorganic aerosols. The concentration of ambient fine particulate matter （PM2.5） is intrinsically connected to public health. In this study, PM2.5-related health impacts of utilizing ammonia-hydrogen energy in Kanto Region, Japan, were investigated. It was assumed that 20% of the electricity consumption in Kanto Region, the most populated area in Japan, was supplied by mnmonia-hydrogen energy. The PM2.5 resulted from incomplete ammonia decomposition was simulated by a chemical transport model： ADMER-PRO （modified version）. Based on the incremental PM2.5 concentration, health impacts on the elderly （individuals over 65 years old） were quantitatively evaluated. The ammonia emission in this scenario increased PM2 s by 11.7% （0.16 μg·m-3.y-1） in winter and 3.5% （0.08 μg · m-3.y-1） in summer, resulting in 351 premature deaths per year. This study suggests that cost- effective emissions control or treatment and appropriate land planning should be considered to reduce the associated health impacts of this type of energy generation. In addition, further in-depth research, including cost-benefit analysis and security standards, is needed.展开更多
Thermally activated building envelopes(TABEs)are multifunctional component that combines structural and energy properties.Based on re-examining the heat charging processes,an arc-shaped metal-fin-enhanced TABE(Arc-fin...Thermally activated building envelopes(TABEs)are multifunctional component that combines structural and energy properties.Based on re-examining the heat charging processes,an arc-shaped metal-fin-enhanced TABE(Arc-finTABE)with directional heat charging features is proposed to optimize the thermal barrier formation process.A comprehensive parameterized analysis is conducted based on a validated mathematical model to explore the influence of 5 fin-structure design parameters and the static insulation thickness.Results verified that the directional charging strengthening fins can improve transient thermal performances of Arc-finATBE and enlarge horizontal and vertical sizes of the thermal energy accumulation area surrounding the pipeline,while the maximum growth in extra heat loss is less than 3.17%.From the perspective of promoting heat injection into expected areas,the straight main fin configurations with the angle of main fins of 30°,shank length ratio of 0.4 and no leftward mounted fins are preferred in load-reduction mode,while the angle of main fins of 150°,shank length ratio of 0.8 and multiple fin designs,especially with one of the main fins horizontally toward the indoor side,are more favorable in auxiliary-heating mode.Besides,it is recommended to add one arc-shaped branch fin to each main fin to achieve a balance between performance improvement and material usage.Moreover,branch fins with larger arc angles are preferred in auxiliary-heating mode,while smaller arc angles are conducive to injecting heat into the wall along main fins in load-reduction mode and preventing the heat near the inner surface from being extracted.Under the direct influence of the strengthened invisible thermal barrier,Arc-finTABEs can reduce the amount of static insulation layer by 20%–80%while achieving equivalent thermal performances as conventional high-performance walls.展开更多
文摘This study investigates the photocatalytic degradation of microcystin-LR (MC-LR) under simulated solar light using Pt modified nano-sized tungsten trioxides (Pt/WO3). Photocatalytic activity was higher during the degradation of MC-LR with Pt/WO 3 than with pure WO 3 or Ti O2 . The catalyst loading greatly affect the degradation performance. The rate of degradation is influenced by the initial pH of the reaction solution. This study also investigates the photocatalytic inactivation of cyanobacteria. The results show that the algal growth was successfully controlled by the Pt/W O 3 . This study suggests Pt/W O 3 photocatalytic oxidation with solar light is a promising treatment for water containing MC-LR.
文摘China is facing the challenge of many marine environment problems with rapid economic growth. Japan had experienced similar marine environmental pressure during its industrialization and had been facing the problem through successful environment policy step by step. The paper reviews the lessons and experiences of Japan’s marine environment protection and analyzes the marine environment pollution in China and its causes, taking Shandong province as a case, such as GDP-oriented economic growth, heavy coal assumption, etc. The paper also analyzes the marine industry with focuses on coastal tourism and its relationship with marine environment. Suggestions on polices are provided based on the analysis on China’ marine environment and Japan’s experience.
文摘The effects of TiO2 photocatalysis on the hydrolysis of protein of waste activated sludge (WAS) and its biodegradability were investigated in this study. After 12-h UV irradiation, the removal ratio of protein by TiO2 photocatalysis reached 98.1%. The optimal condition for photocatalytic degradation of protein is TiO2 dosage of 5.0 mg·L–1 under 2.4 w·m–2 UV light irradiation. TiO2 photocatalysis in comparison with other pretreatments obviously accelerated the hydrolysis of WAS and improved the conversion of total COD (tCOD) to soluble COD (sCOD). The sCOD/tCOD ratio of WAS pretreated by TiO2 photocatalysis, UV photolysis and TiO2 adsorption and that of the control were 92.8%, 32.5%, 18.0% and 16.6%, respectively. TiO2 photocatalytic pretreatment accelerated the biohydrogen production from 10-fold diluted WAS. The bioreactors containing UV photolysis and TiO2 adsorption pretreated WASs and the control reactor require 0.5-d, 0.9-d and 0.7-d start-up period for biohydrogen production, respectively. While the bioreactor containing TiO2 photocatalysis pretreated WAS obtained a hydrogen yield of 0.5 mL-H2/g-VS merely after 0.5-d mesophilic fermentation. The cumulative biohydrogen production from TiO2 photocatalysis pretreated WAS during 4-d mesophilic fermentation reached 11.7 mL-H2/g-VS, which was 1.2 times higher than that from the control. TiO2 photocatalytic pretreatment enhanced the biohydrogen production from WAS via accelerating the hydrolysis of its macromolecular components to smaller molecule weight hydrolysates.
文摘Electrochemical oxidation of ammonia was studied with an objective to enhance the selectivity of ammonia to nitrogen gas and to remove the by-products in an undivided electrochemical cell, in which various cathodes and Ti/RuO 2-Pt anode were assembled. In the present study, anodic oxidation of ammonia and cathodic reduction of by-products were achieved, especially with Cu/Zn as cathode. In the presence of 1.0 g/L NaCl the ammonia-N decreased from 100.0 to 0 after 120 min electrolysis at current density of 30 mA/cm2, and no nitrite was detected in the treated solution. The lowest amount of nitrate was formed with Cu/Zn as cathode during electrolysis due to its high reduction ability. Initial pH range from 7 and 9 and uncontrolled temperature were favorable for electrochemical ammonia oxidation and the ammonia oxidation rates with Cu/Zn cathode was higher than that with Ti and Fe cathode. The reduction rate increased with increasing current density in the range of 5 - 50 mA/cm2. As ammonia could be completely removed by the simultaneous oxidation and reduction in this study, it is suitable for deep treatment of ammonia polluted water.
文摘Chlorsulfuron (ChS) which is a nonbiodegradable herbicide was effectively removed using an electrochemical method at the Ti/IrO2-Pt anode. The influences of current density, initial ChS concentration, initial solution pH and different NaCl dosages on electrochemical degradation of ChS were investigated. HOCl formed during electrolysis and quickly generated .OH radicals would likely play an important role in the electrochemical degradation of ChS with the presence of NaCl. At current density of 20 mA?cm–2, ChS concentration decreased from 1 mg.L–1 to 0 mg.L–1 after 10 min electrolysis with 0.2 g?L–1 NaCl dosage. It was found that the ChS removal rate increased with increasing current density and the ChS degradation was similar at different initial pH values, which means that Ti/IrO2-Pt anode can be used in a wide pH range. The electrochemical performance of Ti/IrO2-Pt anode for degradation of ChS will not decrease after serviced for a long time. These results reveal that an electrochemical approach would be a novel treatment method for effective and rapid degradation of ChS herbicide from aqueous solution.
基金supported by the National Natural Science Foundation of China(No.52200031)。
文摘Anaerobic digestion(AD)of waste activated sludge(WAS)is usually limited by the low generation efficiency of methane.Fe(Ⅲ)-loaded chitosan composite(CTS-Fe)have been reported to effectively enhanced the digestion of WAS,but its role in promoting anaerobic sludge digestion remains unclear.In present study,the effects of CTS-Fe on the hydrolysis and methanogenesis stages of WAS anaerobic digestion were investigated.The addition of CTSFe increased methane production potential by 8%-23%under the tested conditions with the addition of 5-20 g/L CTS-Fe.Besides,the results demonstrate that the addition of CTS-Fe could effectively promote the hydrolysis of WAS,evidenced by lower protein or polysaccharides concentration,higher soluble organic carbon in rector adding CTS-Fe,as well as the increased activity of extracellular hydrolase with higher CTS-Fe concentration.Meanwhile,the enrichment of Clostridia abundance(iron-reducing bacteria(IRBs))was observed in CTS-Fe adding reactor(8.9%-13.8%),which was higher than that in the control reactor(7.9%).The observation further suggesting the acceleration of hydrolysis through dissimilatory iron reduction(DIR)process,thus providing abundant substrates for methanogenesis.However,the presence of CTS-Fe was inhibited the acetoclastic and hydrogenotrophic methanogenesis process,which could be ascribed to the Fe(Ⅲ)act as electron acceptor coupled to methane for anaerobic oxidation.Furthermore,coenzyme F420 activity in the CTS-Fe added reactor was 34.9% lower than in the blank,also abundance of microorganisms involved in hydrogenotrophic methanogenesis was decreased.Results from this study could provide theoretical support for the practical applications of CTS-Fe.
文摘与传统的基于接收信号强度(received signal strength, RSS)的室内Wi-Fi定位方法相比,信道状态信息(channel state information, CSI)包含了信号传输过程中更细粒度和更多样化的物理层信息(如信道中各个子载波的振幅和相位信息),故基于CSI的室内Wi-Fi定位方法通常具有更高的定位精度.在利用CSI进行定位时,发送端采用正交频分复用(orthogonal frequency division multiplexing,OFDM)技术在多个正交子载波上并行发送数据并在接收端进行解调,但由于异步效应(如载波频率偏差(carrier frequency offset, CFO)、采样时钟频率偏差(sampling frequency offset, SFO)和符号定时偏差(symbol timing offset, STO))的存在,接收端子载波的正交性难以得到保证,于是,基于CSI的室内Wi-Fi定位方法的性能会因为符号间干扰(inter symbol interference, ISI)和载波间干扰(inter carrier interference, ICI)的影响而下降.对此,本文从频域的角度推导了不同异步效应下的CSI定位误差界以评估基于CSI的室内Wi-Fi定位性能.
基金supported by National Key R&D Program of China(No.2017YFC0212403).
文摘Mineral dust particles play an important role in the formation of secondary inorganic aerosols, which largely contribute to haze pollution in China.During this study, a haze episode(haze days) and a typical haze process mixed with sandstorm(sandy haze days)were observed in Zhengzhou with a series of high-time-resolution monitoring instruments from November 22 to December 8, 2018.Concentrations of PM10 and crustal elements clearly increased in the sandy haze days.Concentrations of gaseous pollutants, metallic elements emitted from anthropogenic sources, nitrate, and ammonium during sandy haze days were slightly lower than those during the haze days but still obviously higher than those during the non-haze days.The sulfate concentrations, the sulfate fractions in PM2.5,and the sulfur oxidation ratios significantly increased in the sandy haze days.Heterogeneous reactions dominated the conversion of SO2 during the haze and sandy haze days.Enhanced SO2 conversion during the sandy haze days may be attributed to the high concentrations of transition metal ions from the sandstorm when the values of relative humidity(RH) were in 30%–70%, and high O3 at certain time points.Gas-phase NO2 oxidation reactions were the main pathways for nitrate formation.In the sandy haze days,higher nitrogen oxidation ratio(NOR) at daytime may be associated with higher RH and lower temperature than those in the haze days, which facilitate the gas-to-particle partitioning of nitrate;higher NOR values at night may be attributed to the higher O3 concentrations, which promoted the formation of N2O5.
文摘A lab-scale intermittently aerated sequencing batch reactor（IASBR）was applied to treat anaerobically digested swine wastewater（ADSW）to explore the removal characteristics of veterinary antibiotics.The removal rates of 11 veterinary antibiotics in the reactor were investigated under different chemical organic demand（COD）volumetric loadings,solid retention times（SRT）and ratios of COD to total nitrogen（TN）or COD/TN.Both sludge sorption and biodegradation were found to be the major contributors to the removal of veterinary antibiotics.Mass balance analysis revealed that greater than 60%of antibiotics in the influent were biodegraded in the IASBR,whereas averagely 24%were adsorbed by sludge under the condition that sludge sorption gradually reached its equilibrium.Results showed that the removal of antibiotics was greatly influenced by chemical oxygen demand（COD）volumetric loadings,which could achieve up to 85.1%±1.4%at 0.17±0.041 kg COD/m-3/day,while dropped to 75.9%±1.3%and 49.3%±12.1%when COD volumetric loading increased to 0.65±0.032 and1.07±0.073 kg COD/m-3/day,respectively.Tetracyclines,the dominant antibiotics in ADSW,were removed by 87.9%in total at the lowest COD loading,of which 30.4%were contributed by sludge sorption and 57.5%by biodegradation,respectively.In contrast,sulfonamides were removed about 96.2%,almost by biodegradation.Long SRT seemed to have little obvious impact on antibiotics removal,while a shorter SRT of 30–40 day could reduce the accumulated amount of antibiotics and the balanced antibiotics sorption capacity of sludge.Influent COD/TN ratio was found not a key impact factor for veterinary antibiotics removal in this work.
基金supported by the Doctoral Fundation of Jiangsu University (No.1281220014)the Graduate Independent Innovation Foundation of Shandong University (No.yzc09054)
文摘The microstructural evolution of rapidly solidified（RS） ZK60 powders extruded at 250 C was investigated.It was shown that formation of new ultrafine grains took place through continuous dynamic recrystallization（CDRX）,accompanied by the perfect bonding of powders via severe plastic deformation.At a low strain level,a well-defined structure made up of equiaxed and elongated subgrains was developed.Simultaneously,the operation of basal and non-basal dislocation slip led to the formation of low-angle dislocation cells（LADC） within the elongated subgrains.With increasing strain,the number and average misorientation of LADC increased,resulting in fragmentation of original elongation subgrains into a finally homogeneous fine-grained structure.Almost full-recrystallized structure with an average grain size of 0.4 μm was finally evolved after large cumulative strain.The results suggested that structural change was connected with thermal strain,where dislocation activities dominated this process.
文摘Ammonia has emerged as a promising hydrogen carrier with applications as an energy source in recent years. However, in addition to being toxic, gaseous ammonia is a precursor of secondary inorganic aerosols. The concentration of ambient fine particulate matter （PM2.5） is intrinsically connected to public health. In this study, PM2.5-related health impacts of utilizing ammonia-hydrogen energy in Kanto Region, Japan, were investigated. It was assumed that 20% of the electricity consumption in Kanto Region, the most populated area in Japan, was supplied by mnmonia-hydrogen energy. The PM2.5 resulted from incomplete ammonia decomposition was simulated by a chemical transport model： ADMER-PRO （modified version）. Based on the incremental PM2.5 concentration, health impacts on the elderly （individuals over 65 years old） were quantitatively evaluated. The ammonia emission in this scenario increased PM2 s by 11.7% （0.16 μg·m-3.y-1） in winter and 3.5% （0.08 μg · m-3.y-1） in summer, resulting in 351 premature deaths per year. This study suggests that cost- effective emissions control or treatment and appropriate land planning should be considered to reduce the associated health impacts of this type of energy generation. In addition, further in-depth research, including cost-benefit analysis and security standards, is needed.
基金co-sponsored by the National Natural Science Foundation of China(No.52208103)Fundamental Research Funds for the Central Universities(No.JZ2024HGTB0229)+2 种基金Opening Fund of Anhui Province Key Laboratory of Intelligent Building&Building Energy Saving(No.IBES2024KF05,IBES2024ZR03)Anhui Province University Outstanding Scientific Research and Innovation Team(No.2022AH010021)Scientific Research and Cultivation Project of Anhui Jianzhu University(No.2021XMK04).
文摘Thermally activated building envelopes(TABEs)are multifunctional component that combines structural and energy properties.Based on re-examining the heat charging processes,an arc-shaped metal-fin-enhanced TABE(Arc-finTABE)with directional heat charging features is proposed to optimize the thermal barrier formation process.A comprehensive parameterized analysis is conducted based on a validated mathematical model to explore the influence of 5 fin-structure design parameters and the static insulation thickness.Results verified that the directional charging strengthening fins can improve transient thermal performances of Arc-finATBE and enlarge horizontal and vertical sizes of the thermal energy accumulation area surrounding the pipeline,while the maximum growth in extra heat loss is less than 3.17%.From the perspective of promoting heat injection into expected areas,the straight main fin configurations with the angle of main fins of 30°,shank length ratio of 0.4 and no leftward mounted fins are preferred in load-reduction mode,while the angle of main fins of 150°,shank length ratio of 0.8 and multiple fin designs,especially with one of the main fins horizontally toward the indoor side,are more favorable in auxiliary-heating mode.Besides,it is recommended to add one arc-shaped branch fin to each main fin to achieve a balance between performance improvement and material usage.Moreover,branch fins with larger arc angles are preferred in auxiliary-heating mode,while smaller arc angles are conducive to injecting heat into the wall along main fins in load-reduction mode and preventing the heat near the inner surface from being extracted.Under the direct influence of the strengthened invisible thermal barrier,Arc-finTABEs can reduce the amount of static insulation layer by 20%–80%while achieving equivalent thermal performances as conventional high-performance walls.
