High humidity and high dust concentration in deep coal mines may severely challenge the performance of respirators worn by coal miners.This paper aims at quantitatively evaluating the respirators used in deep coal min...High humidity and high dust concentration in deep coal mines may severely challenge the performance of respirators worn by coal miners.This paper aims at quantitatively evaluating the respirators used in deep coal mines and providing scientific guidance for the respiratory protection of miners.Based on the self-designed in-situ PM2.5 collector,controllable PM2.5 generator,human breathing simulator,and respirator simulation testing system,under the simulated deep mine working condition,this study investigated the effects of dust loading,wearing time,and dust concentration on the filtration efficiency,breathing resistance,and quality factor of N95 elastomeric respirators.With the increase of dust loading,the respirator filtration efficiency firstly decreased,then increased(minimum value 97.5%).The breathing resistance increased exponentially from 120 to 180 to 1020-1530 Pa,and the quality factor decreased logarithmically from 0.051 to 0.076 to 0.0058-0.0085 Pa^(-1).As the PM2.5 coal dust concentration increased from 5 to 50 mg/m^(3),the wearing time for the respirator breathing resistance to exceed 300 Pa reduced from 7 h to less than 1 h.One N95 elastomeric respirator is not able to perform an 8-h work shift.To avoid the excessive breathing resistance caused by dust loading,more filter cartridges are needed for coal miners.展开更多
首先介绍中国GB/T 14295-2008、欧洲EN 779-2011、美国ANSI/ASHRAE Standard 52.2-2007关于一般通风空调用空气过滤器测试标准的发展背景及相关国内外研究现状,然后从过滤器测试方法、分级方法、过滤器初阻力性能等方面对三个标准进行...首先介绍中国GB/T 14295-2008、欧洲EN 779-2011、美国ANSI/ASHRAE Standard 52.2-2007关于一般通风空调用空气过滤器测试标准的发展背景及相关国内外研究现状,然后从过滤器测试方法、分级方法、过滤器初阻力性能等方面对三个标准进行了比较,最后对EUROVENT 4/11-2010关于过滤器能效分级方法的优点和不足进行简要分析。展开更多
A program of house dust sample collection and analysis has begun in Syracuse,New York,USA,in order to determine the feasibility of a geography-based exposure assessment for urban metals.The sampling program,and the pr...A program of house dust sample collection and analysis has begun in Syracuse,New York,USA,in order to determine the feasibility of a geography-based exposure assessment for urban metals.The sampling program,and the protocols it employs,is described for two different types of wipe media,Ghost Wipes and Whatman Filters.Preliminary results show that strong spatial patterns of floor dust loading(mg dust per square foot)can be observed for data aggregated at a spatial scale of about 1600 m(~2.5 km^(2)).Floor dust metal concentrations were similar to those found in other urban environments,with some regional variation.The median floor dust Pb concentration was~108 mg·kg^(-1)for this initial data set of~264 sampled residential locations,and varied from 50 to 1100 mg Pb·kg^(-1).展开更多
Eighty sites were set up to monitor road dust fall and 80 locations were selected to sample silt loading in April, August, and November 2007 and January 2008 in the Beijing metropolitan area. Fugitive road dust emissi...Eighty sites were set up to monitor road dust fall and 80 locations were selected to sample silt loading in April, August, and November 2007 and January 2008 in the Beijing metropolitan area. Fugitive road dust emission strengths were calculated using the AP-42 emission factor model. Silt loading on Beijing urban roads was typically less than 1.0 g/m^2, the PM10 emission strength was typically less than 100 kg/km·day, and road dust fall was typically less than 40 t/km^2·30day. The relationships between traffic volume, silt loading, fugitive road dust emission strength and road dust fall were studied in the Beijing metropolitan area. The results indicate that silt loading and emission factors are negatively correlated with traffic volume, but the PM10 emission rate and road dust-fall are positively correlated with traffic volume.展开更多
Modeling has become phenomenal in developing new products.In the case of filters,one of the mos applied procedures is via the construction of idealized physical computational models bearing close semblance to real fil...Modeling has become phenomenal in developing new products.In the case of filters,one of the mos applied procedures is via the construction of idealized physical computational models bearing close semblance to real filter media.It is upon these that multi-physics tools were applied to analvze the fow of fuid and the resulting typical performance parameters.In this work,two 3D filter membranes were constructed with MATLAB:one had a random distribution of unimodal nanofibers,and the other,a novel modification,formed.a bimodal distribution:both of them had similar dimensions and solid volume fractions.A comparison of their performance in a dust-loading environment was made by using computational fluid dynamic-discrete elemen method(CED-DEM)coupling technique in STAR-CCM+.It was found that the bimodal nanofiber membrane greatly improved the particle capture efficiencv.Whereas this increased the pressure drop,the gain was not toosignificant.Thus.overall,the results of the figure of merit ptoved that adopting a bimodal formation improved the filter's quality.展开更多
基金supported by the National Natural Science Foundation of China(No.51904291)the Basic Research Program of Jiangsu Province(No.BK20190638)+2 种基金the Fundamental Research Funds for the Central Universities(No.2020XGYJ08)the Project funded by China Postdoctoral Science Foundation(No.2020 M681781),the Jiangsu Planned Projects for Postdoctoral Research Funds(No.2020Z076)the State Key Laboratory of Strata Intelligent Control and Green Mining Co-founded by Shandong Province and the Ministry of Science and Technology(No.SICGM202105).
文摘High humidity and high dust concentration in deep coal mines may severely challenge the performance of respirators worn by coal miners.This paper aims at quantitatively evaluating the respirators used in deep coal mines and providing scientific guidance for the respiratory protection of miners.Based on the self-designed in-situ PM2.5 collector,controllable PM2.5 generator,human breathing simulator,and respirator simulation testing system,under the simulated deep mine working condition,this study investigated the effects of dust loading,wearing time,and dust concentration on the filtration efficiency,breathing resistance,and quality factor of N95 elastomeric respirators.With the increase of dust loading,the respirator filtration efficiency firstly decreased,then increased(minimum value 97.5%).The breathing resistance increased exponentially from 120 to 180 to 1020-1530 Pa,and the quality factor decreased logarithmically from 0.051 to 0.076 to 0.0058-0.0085 Pa^(-1).As the PM2.5 coal dust concentration increased from 5 to 50 mg/m^(3),the wearing time for the respirator breathing resistance to exceed 300 Pa reduced from 7 h to less than 1 h.One N95 elastomeric respirator is not able to perform an 8-h work shift.To avoid the excessive breathing resistance caused by dust loading,more filter cartridges are needed for coal miners.
基金the National Natural Science Foundation(Grant No.BCS-0221949).
文摘A program of house dust sample collection and analysis has begun in Syracuse,New York,USA,in order to determine the feasibility of a geography-based exposure assessment for urban metals.The sampling program,and the protocols it employs,is described for two different types of wipe media,Ghost Wipes and Whatman Filters.Preliminary results show that strong spatial patterns of floor dust loading(mg dust per square foot)can be observed for data aggregated at a spatial scale of about 1600 m(~2.5 km^(2)).Floor dust metal concentrations were similar to those found in other urban environments,with some regional variation.The median floor dust Pb concentration was~108 mg·kg^(-1)for this initial data set of~264 sampled residential locations,and varied from 50 to 1100 mg Pb·kg^(-1).
文摘Eighty sites were set up to monitor road dust fall and 80 locations were selected to sample silt loading in April, August, and November 2007 and January 2008 in the Beijing metropolitan area. Fugitive road dust emission strengths were calculated using the AP-42 emission factor model. Silt loading on Beijing urban roads was typically less than 1.0 g/m^2, the PM10 emission strength was typically less than 100 kg/km·day, and road dust fall was typically less than 40 t/km^2·30day. The relationships between traffic volume, silt loading, fugitive road dust emission strength and road dust fall were studied in the Beijing metropolitan area. The results indicate that silt loading and emission factors are negatively correlated with traffic volume, but the PM10 emission rate and road dust-fall are positively correlated with traffic volume.
基金the Chang Jiang Youth Scholars Program of China(No.51773037)the National Natural Science Foundation of China(Nos.51803023 and 61771123)+2 种基金the Shanghai Sailing Program(No.18YF1400400)the China Postdoctoral Science Foundation(No.2018M640317)the Fundamental Hesearch Funds for the Central Universities(No.2232018A3-11)。
文摘Modeling has become phenomenal in developing new products.In the case of filters,one of the mos applied procedures is via the construction of idealized physical computational models bearing close semblance to real filter media.It is upon these that multi-physics tools were applied to analvze the fow of fuid and the resulting typical performance parameters.In this work,two 3D filter membranes were constructed with MATLAB:one had a random distribution of unimodal nanofibers,and the other,a novel modification,formed.a bimodal distribution:both of them had similar dimensions and solid volume fractions.A comparison of their performance in a dust-loading environment was made by using computational fluid dynamic-discrete elemen method(CED-DEM)coupling technique in STAR-CCM+.It was found that the bimodal nanofiber membrane greatly improved the particle capture efficiencv.Whereas this increased the pressure drop,the gain was not toosignificant.Thus.overall,the results of the figure of merit ptoved that adopting a bimodal formation improved the filter's quality.
