A cement factory nearby communities raise pollution concerns. This study assessed air pollution levels for respirable particulate matter (PM2.5 and PM10) and heavy metals (lead, chromium, nickel, cadmium, zinc and cop...A cement factory nearby communities raise pollution concerns. This study assessed air pollution levels for respirable particulate matter (PM2.5 and PM10) and heavy metals (lead, chromium, nickel, cadmium, zinc and copper) adjacent to a cement factory in Ewekoro and neighbouring communities (Papalantoro, Lapeleko and Itori) in Ogun State, Nigeria. Respirable particulate matter (PM2.5 and PM10) and heavy metals were measured using an ARA N-FRM cassette sampler. Each location sampled was monitored for eight continuous hours daily for 12 days. The PM2.5, PM10 and heavy metals results were compared with different standards, including those of the World Health Organization (WHO), Nigeria’s National Environmental Standard and Regulation Enforcement Agency (NESREA) and Canadian Ambient Air Quality Standards (CAAQS). The PM levels fell within 11 - 19 μg/m3 of the air management level of CAAQS, which signifies continuous actions are needed to improve air quality in the areas monitored but below the NESREA standard. The mean Cd, Cr and Ni concentrations in the cement factory area and the impacted neighbourhoods are higher than the WHO/EU permissible limits, while Zn and Cu were below the WHO/EU permissible limit. A risk assessment hazard quotient (HQ) for Cr was above the WHO/EU safe level (=1) in adults and children throµgh ingestion, inhalation and dermal contact at all the monitoring sites. The HQ for Ni and Cd was higher than the safe level in the cement factory area and Papalantoro, while Zn was at safe levels.展开更多
With the rapid development of wearable and intelligent flexible electronic devices(FEDs),the demand for flexible energy storage/conversion devices(ESCDs)has also increased.Rechargeable flexible metal‐air batteries(MA...With the rapid development of wearable and intelligent flexible electronic devices(FEDs),the demand for flexible energy storage/conversion devices(ESCDs)has also increased.Rechargeable flexible metal‐air batteries(MABs)are expected to be one of the most ideal ESCDs due to their high theoretical energy density,cost advantage,and strong deformation adaptability.With the improvement of the device design,material assemblies,and manufacturing technology,the research on the electrochemical performance of flexible MABs has made significant progress.However,achieving the high mechanical flexibility,high safety,and wearable comfortability required by FEDs while maintaining the high performance of flexible MABs are still a daunting challenge.In this review,flexible Zn‐air and Li‐air batteries are mainly exemplified to describe the most recent progress and challenges of flexible MABs.We start with an overview of the structure and configuration of the flexible MABs and discuss their impact on battery performance and function.Then it focuses on the research progress of flexible metal anodes,gel polymer electrolytes,and air cathodes.Finally,the main challenges and future research perspectives involving flexible MABs for FEDs are proposed.展开更多
Rechargeable alkali metal-air batteries are considered as the most promising candidate for the power source of electric vehicles(EVs) due to their high energy density. However, the practical application of metal-air b...Rechargeable alkali metal-air batteries are considered as the most promising candidate for the power source of electric vehicles(EVs) due to their high energy density. However, the practical application of metal-air batteries is still challenging. In the past decade, many strategies have been purposed and explored, which promoted the development of metal-air batteries. The reaction mechanisms have been gradually clarified and catalysts have been rationally designed for air cathodes. In this review, we summarize the recent development of alkali metal-air batteries from four parts: metal anodes, electrolytes, air cathodes and reactant gases, wherein we highlight the important achievement in this filed. Finally problems and prospective are discussed towards the future development of alkali metal-air batteries.展开更多
This work creates a droplet battery model based on the electrolyte performance in the porous electrode, studies the current density on the mesoscopic scale, and explains how the mesoscopic structure of the porous elec...This work creates a droplet battery model based on the electrolyte performance in the porous electrode, studies the current density on the mesoscopic scale, and explains how the mesoscopic structure of the porous electrode influences the current density on the air-diffusion electrode. Near the three-phase line, there is a strong band containing nearly 80% current. For porous electrodes, the total current is proportional to the length of the strong band. Thus, it can be inferred that on the macroscopic scale, the longer the total length of the strong band on unit area is, the larger the current density is.展开更多
Air pollution present the greatest threat to human health and welfare in urban environments. Population growth, industrial activities, expanded transport system, vehicular traffic, poor road planning, poor land use an...Air pollution present the greatest threat to human health and welfare in urban environments. Population growth, industrial activities, expanded transport system, vehicular traffic, poor road planning, poor land use and traffic congestion contribute to the problem. Particulate matter (PM<sub>2.5</sub> and PM<sub>10</sub>) has become the principal pollutants due to increased material use, energy demand and use as a result of global economic growth. This study assessed the levels of PM<sub>10</sub> in ambient air and heavy metal composition in Nairobi city. Sampling sites were classified into three categories namely;controlled areas, industrial and residential areas as proscribed in the EMCA Air Quality Regulations, 2014. Portable Mini-Vol ambient air samplers were used for fine particulate monitoring. The concentrations of manganese, lead, and cadmium was determined in PM<sub>10</sub> samples from all sampling sites. The lead concentration mean was 0.07 ± 0.06 μg/m<sup>3</sup>, 0.34 ± 0.35 μg/m<sup>3</sup> and 1.10 ± 0.59 μg/m<sup>3</sup> for residential, controlled and industrial areas respectively. Generally, all afternoons had high particulate matter while the lowest concentration levels of PM<sub>10</sub> were recorded at night.展开更多
The relationship among the hydrogen storage properties, cycling characteristics and thermal parameters of the metal hydride air conditioning systems was investigated. Based on a new alloy selection model, three pairs ...The relationship among the hydrogen storage properties, cycling characteristics and thermal parameters of the metal hydride air conditioning systems was investigated. Based on a new alloy selection model, three pairs of hydrogen storage alloys, LaNi_ 4.4 Mn_ 0.26 Al_ 0.34 / La_ 0.6 Nd_ 0.4 Ni_ 4.8 Mn_ 0.2 Cu_ 0.1 ,LaNi_ 4.61 Mn_ 0.26 Al_ 0.13 /La_ 0.6 Nd_ 0.4 Ni_ 4.8 Mn_ 0.2 Cu_ 0.1 and LaNi_ 4.61 Mn_ 0.26 Al_ 0.13 /La_ 0.6 Y_ 0.4 Ni_ 4.8 Mn_ 0.2 , were selected as the working materials for the metal hydride air conditioning system. Studies on the factors affecting the COP of the system showed that higher COP and available hydrogen content need the proper operating temperature and cycling time,large hydrogen storage capacity, flat plateau and small hysterisis of hydrogen alloys, proper original input hydrogen content and mass ratio of the pair of alloys. It also needs small weight, heat capacity and good heat conductivity of the reaction beds. An experimental metal hydride air-conditioning system was established by using LaNi_ 4.61 Mn_ 0.26 Al_ 0.13 /La_ 0.6 Y_ 0.4 Ni_ 4.8 Mn_ 0.2 alloys as the working materials, which showed that under the operating temperature of 180℃/40℃, a low temperature of 13℃ was reached, with COP =0.38 and W_ net =0.09 kW/kg.展开更多
The paper analyzed the concentrations of trace metals in fine and respirable particulates (fine-PM<sub>1</sub> and PM<sub>2.5</sub>;respirable-PM<sub>10</sub>) to determine baseline...The paper analyzed the concentrations of trace metals in fine and respirable particulates (fine-PM<sub>1</sub> and PM<sub>2.5</sub>;respirable-PM<sub>10</sub>) to determine baseline concentrations in the ambient air and the factors impacting its distribution such as land use and time of year when levels may be concerning to public health. Measurements of particulates along with meteorological parameters were made at four sites over the heavily populated west coast of Trinidad (10<span style="font-size:10.0pt;font-family:;" "=""><span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">°</span></span>32'N, 61<span style="font-size:10.0pt;font-family:;" "=""><span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">°</span></span>18'W) during March ’15-May ’16, representing rural, urban, mixed background and industrial land uses. The study found mean levels of trace metals to be highest at the industrial and urban stations. Public health exceedances (referenced to the Canadian AAQ public health standards <a href="#ref23">(Ontario-MoE, 2012)</a>) were measured for beryllium, cadmium, chromium, iron, manganese and nickel (in PM<sub>10</sub>). Iron, manganese and nickel, most associated with particulates at the industrial station, were in frequent exceedance. Beryllium—concentrated in coarse PM (PM<sub>2.5-10</sub>) with only a single measured exceedance at the mixed background station likely poses minimal threat to the health of the nearby population. Cadmium—concentrated in fine PM which peaked once only at the rural station was likely due to an irregular event within a narrow timeframe during the time of sampling. Iron and manganese were frequently above the Canadian public health threshold, but predominated in the coarse PM fraction, suggesting localised sources. Nickel, concentrated in the fine PM fraction, was frequently in exceedance particularly at the industrial station. Cadmium and nickel are genotoxic and should be regulated in order to reduce the burden of toxic carcinogens to which the population can be exposed.展开更多
文摘A cement factory nearby communities raise pollution concerns. This study assessed air pollution levels for respirable particulate matter (PM2.5 and PM10) and heavy metals (lead, chromium, nickel, cadmium, zinc and copper) adjacent to a cement factory in Ewekoro and neighbouring communities (Papalantoro, Lapeleko and Itori) in Ogun State, Nigeria. Respirable particulate matter (PM2.5 and PM10) and heavy metals were measured using an ARA N-FRM cassette sampler. Each location sampled was monitored for eight continuous hours daily for 12 days. The PM2.5, PM10 and heavy metals results were compared with different standards, including those of the World Health Organization (WHO), Nigeria’s National Environmental Standard and Regulation Enforcement Agency (NESREA) and Canadian Ambient Air Quality Standards (CAAQS). The PM levels fell within 11 - 19 μg/m3 of the air management level of CAAQS, which signifies continuous actions are needed to improve air quality in the areas monitored but below the NESREA standard. The mean Cd, Cr and Ni concentrations in the cement factory area and the impacted neighbourhoods are higher than the WHO/EU permissible limits, while Zn and Cu were below the WHO/EU permissible limit. A risk assessment hazard quotient (HQ) for Cr was above the WHO/EU safe level (=1) in adults and children throµgh ingestion, inhalation and dermal contact at all the monitoring sites. The HQ for Ni and Cd was higher than the safe level in the cement factory area and Papalantoro, while Zn was at safe levels.
基金supported by the the National Natural This study was financially supported by the National Youth Top‐notch Talent Support Program,the State Key Laboratory of Pulp and Paper Engineering Funds(2020C03)the National Natural Science Foundation of China(31971614,32071714,21736003,and 52003083)+2 种基金Guangzhou Science and Technology Funds(201904010078 and 202002030167)the China Postdoctoral Science Foundation funded project(2019T120725,2019M652882,2019M662924,2020M682711,and 2020M682710)Guangdong Basic and Applied Basic Research Foundation(2020A1515110705)。
文摘With the rapid development of wearable and intelligent flexible electronic devices(FEDs),the demand for flexible energy storage/conversion devices(ESCDs)has also increased.Rechargeable flexible metal‐air batteries(MABs)are expected to be one of the most ideal ESCDs due to their high theoretical energy density,cost advantage,and strong deformation adaptability.With the improvement of the device design,material assemblies,and manufacturing technology,the research on the electrochemical performance of flexible MABs has made significant progress.However,achieving the high mechanical flexibility,high safety,and wearable comfortability required by FEDs while maintaining the high performance of flexible MABs are still a daunting challenge.In this review,flexible Zn‐air and Li‐air batteries are mainly exemplified to describe the most recent progress and challenges of flexible MABs.We start with an overview of the structure and configuration of the flexible MABs and discuss their impact on battery performance and function.Then it focuses on the research progress of flexible metal anodes,gel polymer electrolytes,and air cathodes.Finally,the main challenges and future research perspectives involving flexible MABs for FEDs are proposed.
基金supported by NSFC(21473094 and21421001)MOE Innovation Team(IRT13022) in China
文摘Rechargeable alkali metal-air batteries are considered as the most promising candidate for the power source of electric vehicles(EVs) due to their high energy density. However, the practical application of metal-air batteries is still challenging. In the past decade, many strategies have been purposed and explored, which promoted the development of metal-air batteries. The reaction mechanisms have been gradually clarified and catalysts have been rationally designed for air cathodes. In this review, we summarize the recent development of alkali metal-air batteries from four parts: metal anodes, electrolytes, air cathodes and reactant gases, wherein we highlight the important achievement in this filed. Finally problems and prospective are discussed towards the future development of alkali metal-air batteries.
文摘This work creates a droplet battery model based on the electrolyte performance in the porous electrode, studies the current density on the mesoscopic scale, and explains how the mesoscopic structure of the porous electrode influences the current density on the air-diffusion electrode. Near the three-phase line, there is a strong band containing nearly 80% current. For porous electrodes, the total current is proportional to the length of the strong band. Thus, it can be inferred that on the macroscopic scale, the longer the total length of the strong band on unit area is, the larger the current density is.
文摘Air pollution present the greatest threat to human health and welfare in urban environments. Population growth, industrial activities, expanded transport system, vehicular traffic, poor road planning, poor land use and traffic congestion contribute to the problem. Particulate matter (PM<sub>2.5</sub> and PM<sub>10</sub>) has become the principal pollutants due to increased material use, energy demand and use as a result of global economic growth. This study assessed the levels of PM<sub>10</sub> in ambient air and heavy metal composition in Nairobi city. Sampling sites were classified into three categories namely;controlled areas, industrial and residential areas as proscribed in the EMCA Air Quality Regulations, 2014. Portable Mini-Vol ambient air samplers were used for fine particulate monitoring. The concentrations of manganese, lead, and cadmium was determined in PM<sub>10</sub> samples from all sampling sites. The lead concentration mean was 0.07 ± 0.06 μg/m<sup>3</sup>, 0.34 ± 0.35 μg/m<sup>3</sup> and 1.10 ± 0.59 μg/m<sup>3</sup> for residential, controlled and industrial areas respectively. Generally, all afternoons had high particulate matter while the lowest concentration levels of PM<sub>10</sub> were recorded at night.
基金The Natural Science Foundation of China (50266063) .
文摘The relationship among the hydrogen storage properties, cycling characteristics and thermal parameters of the metal hydride air conditioning systems was investigated. Based on a new alloy selection model, three pairs of hydrogen storage alloys, LaNi_ 4.4 Mn_ 0.26 Al_ 0.34 / La_ 0.6 Nd_ 0.4 Ni_ 4.8 Mn_ 0.2 Cu_ 0.1 ,LaNi_ 4.61 Mn_ 0.26 Al_ 0.13 /La_ 0.6 Nd_ 0.4 Ni_ 4.8 Mn_ 0.2 Cu_ 0.1 and LaNi_ 4.61 Mn_ 0.26 Al_ 0.13 /La_ 0.6 Y_ 0.4 Ni_ 4.8 Mn_ 0.2 , were selected as the working materials for the metal hydride air conditioning system. Studies on the factors affecting the COP of the system showed that higher COP and available hydrogen content need the proper operating temperature and cycling time,large hydrogen storage capacity, flat plateau and small hysterisis of hydrogen alloys, proper original input hydrogen content and mass ratio of the pair of alloys. It also needs small weight, heat capacity and good heat conductivity of the reaction beds. An experimental metal hydride air-conditioning system was established by using LaNi_ 4.61 Mn_ 0.26 Al_ 0.13 /La_ 0.6 Y_ 0.4 Ni_ 4.8 Mn_ 0.2 alloys as the working materials, which showed that under the operating temperature of 180℃/40℃, a low temperature of 13℃ was reached, with COP =0.38 and W_ net =0.09 kW/kg.
文摘The paper analyzed the concentrations of trace metals in fine and respirable particulates (fine-PM<sub>1</sub> and PM<sub>2.5</sub>;respirable-PM<sub>10</sub>) to determine baseline concentrations in the ambient air and the factors impacting its distribution such as land use and time of year when levels may be concerning to public health. Measurements of particulates along with meteorological parameters were made at four sites over the heavily populated west coast of Trinidad (10<span style="font-size:10.0pt;font-family:;" "=""><span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">°</span></span>32'N, 61<span style="font-size:10.0pt;font-family:;" "=""><span style="color:#4F4F4F;font-family:"font-size:14px;white-space:normal;background-color:#FFFFFF;">°</span></span>18'W) during March ’15-May ’16, representing rural, urban, mixed background and industrial land uses. The study found mean levels of trace metals to be highest at the industrial and urban stations. Public health exceedances (referenced to the Canadian AAQ public health standards <a href="#ref23">(Ontario-MoE, 2012)</a>) were measured for beryllium, cadmium, chromium, iron, manganese and nickel (in PM<sub>10</sub>). Iron, manganese and nickel, most associated with particulates at the industrial station, were in frequent exceedance. Beryllium—concentrated in coarse PM (PM<sub>2.5-10</sub>) with only a single measured exceedance at the mixed background station likely poses minimal threat to the health of the nearby population. Cadmium—concentrated in fine PM which peaked once only at the rural station was likely due to an irregular event within a narrow timeframe during the time of sampling. Iron and manganese were frequently above the Canadian public health threshold, but predominated in the coarse PM fraction, suggesting localised sources. Nickel, concentrated in the fine PM fraction, was frequently in exceedance particularly at the industrial station. Cadmium and nickel are genotoxic and should be regulated in order to reduce the burden of toxic carcinogens to which the population can be exposed.
