The Experts below are selected from a list of 222 Experts worldwide ranked by ideXlab platform

Donald R. Blake - One of the best experts on this subject based on the ideXlab platform.

  • vehicular fuel composition and atmospheric emissions in south china hong kong macau guangzhou and zhuhai
    Atmospheric Chemistry and Physics, 2006
    Co-Authors: Waiyan Tsai, L. Y. Chan, Donald R. Blake
    Abstract:

    Vehicular emission is an important source of air pollutants in urban cities in the Pearl River Delta (PRD) re- gion of South China. In order to study the impact of evapo- rative Loss of vehicular fuel on air quality, several commonly used fuel samples were collected in four main cities in the PRD region - Hong Kong, Guangzhou, Macau and Zhuhai, and analyzed for their volatile organic compounds (VOCs) composition. Source profiles of vapors of the vehicular fu- els used in these cities were constructed and are believed to be the first reported for the PRD region. The C 8-C10 hy- drocarbons were the main constituents of diesel. Different from diesel, gasoline used in the PRD region was mainly comprised of lighter C4-C7 hydrocarbons, with toluene and i-pentane being the two most abundant species. The toluene content in the Hong Kong and Macau gasoline samples were higher than that in Guangzhou and Zhuhai, while the re- verse was true for the benzene content. The benzene levels in Guangzhou and Zhuhai exceeded the maximum allowable benzene levels for Mainland China unleaded gasoline. Liq- uefied Petroleum Gas (LPG) samples were collected only in Hong Kong and were comprised mainly of n-butane, propane and i-butane. Traffic samples indicated that Evaporative Loss and vehicular combustion were the primary contributors to elevated VOC levels in roadside atmospheres. Significant i-pentane and toluene concentrations were observed in road- side atmospheres in all four cities. Ratio of i-pentane in gaso- line vapors to that in roadside samples were calculated and this showed that the degree of Evaporative Loss were higher in Guangzhou and Zhuhai than that in Hong Kong and Macau. We suggest the difference is due to the better maintenance and more new cars in Hong Kong and Macau. From tunnel samples collected in Hong Kong in two different years, we found that the relative amount of propane, i-butane, and n- butane increased between 2001 to 2003, consistent with the

  • Vehicular fuel composition and atmospheric emissions in South China: Hong Kong, Macau, Guangzhou, and Zhuhai
    Atmospheric Chemistry and Physics Discussions, 2006
    Co-Authors: W.-y. Tsai, L. Y. Chan, Donald R. Blake, K. W. Chu
    Abstract:

    Vehicular emission is an important source of air pollutants in urban cities in the Pearl River Delta (PRD) region of South China. In order to study the impact of Evaporative Loss of vehicular fuel on air quality, several commonly used fuel samples were collected in four main cities in the PRD region - Hong Kong, Guangzhou, Macau and Zhuhai, and analyzed for their volatile organic compounds (VOCs) composition. Source profiles of vapors of the vehicular fuels used in these cities were constructed and are believed to be the first reported for the PRD region. The C-8-C-10 hydrocarbons were the main constituents of diesel. Different from diesel, gasoline used in the PRD region was mainly comprised of lighter C-4-C-7 hydrocarbons, with toluene and i-pentane being the two most abundant species. The toluene content in the Hong Kong and Macau gasoline samples were higher than that in Guangzhou and Zhuhai, while the reverse was true for the benzene content. The benzene levels in Guangzhou and Zhuhai exceeded the maximum allowable benzene levels for Mainland China unleaded gasoline. Liquefied Petroleum Gas (LPG) samples were collected only in Hong Kong and were comprised mainly of n-butane, propane and i-butane. Traffic samples indicated that Evaporative Loss and vehicular combustion were the primary contributors to elevated VOC levels in roadside atmospheres. Significant i-pentane and toluene concentrations were observed in roadside atmospheres in all four cities. Ratio of i-pentane in gasoline vapors to that in roadside samples were calculated and this showed that the degree of Evaporative Loss were higher in Guangzhou and Zhuhai than that in Hong Kong and Macau. We suggest the difference is due to the better maintenance and more new cars in Hong Kong and Macau. From tunnel samples collected in Hong Kong in two different years, we found that the relative amount of propane, i-butane, and n-butane increased between 2001 to 2003, consistent with the 40% increase in LPG fueled vehicles. Propane to butanes ratios were calculated for LPG samples and tunnels samples, and the comparable ratios illustrated the LPG leakages from LPG fueled vehicles crossing the tunnel.

K. W. Chu - One of the best experts on this subject based on the ideXlab platform.

  • Vehicular fuel composition and atmospheric emissions in South China: Hong Kong, Macau, Guangzhou, and Zhuhai
    Atmospheric Chemistry and Physics Discussions, 2006
    Co-Authors: W.-y. Tsai, L. Y. Chan, Donald R. Blake, K. W. Chu
    Abstract:

    Vehicular emission is an important source of air pollutants in urban cities in the Pearl River Delta (PRD) region of South China. In order to study the impact of Evaporative Loss of vehicular fuel on air quality, several commonly used fuel samples were collected in four main cities in the PRD region - Hong Kong, Guangzhou, Macau and Zhuhai, and analyzed for their volatile organic compounds (VOCs) composition. Source profiles of vapors of the vehicular fuels used in these cities were constructed and are believed to be the first reported for the PRD region. The C-8-C-10 hydrocarbons were the main constituents of diesel. Different from diesel, gasoline used in the PRD region was mainly comprised of lighter C-4-C-7 hydrocarbons, with toluene and i-pentane being the two most abundant species. The toluene content in the Hong Kong and Macau gasoline samples were higher than that in Guangzhou and Zhuhai, while the reverse was true for the benzene content. The benzene levels in Guangzhou and Zhuhai exceeded the maximum allowable benzene levels for Mainland China unleaded gasoline. Liquefied Petroleum Gas (LPG) samples were collected only in Hong Kong and were comprised mainly of n-butane, propane and i-butane. Traffic samples indicated that Evaporative Loss and vehicular combustion were the primary contributors to elevated VOC levels in roadside atmospheres. Significant i-pentane and toluene concentrations were observed in roadside atmospheres in all four cities. Ratio of i-pentane in gasoline vapors to that in roadside samples were calculated and this showed that the degree of Evaporative Loss were higher in Guangzhou and Zhuhai than that in Hong Kong and Macau. We suggest the difference is due to the better maintenance and more new cars in Hong Kong and Macau. From tunnel samples collected in Hong Kong in two different years, we found that the relative amount of propane, i-butane, and n-butane increased between 2001 to 2003, consistent with the 40% increase in LPG fueled vehicles. Propane to butanes ratios were calculated for LPG samples and tunnels samples, and the comparable ratios illustrated the LPG leakages from LPG fueled vehicles crossing the tunnel.

L. Y. Chan - One of the best experts on this subject based on the ideXlab platform.

  • vehicular fuel composition and atmospheric emissions in south china hong kong macau guangzhou and zhuhai
    Atmospheric Chemistry and Physics, 2006
    Co-Authors: Waiyan Tsai, L. Y. Chan, Donald R. Blake
    Abstract:

    Vehicular emission is an important source of air pollutants in urban cities in the Pearl River Delta (PRD) re- gion of South China. In order to study the impact of evapo- rative Loss of vehicular fuel on air quality, several commonly used fuel samples were collected in four main cities in the PRD region - Hong Kong, Guangzhou, Macau and Zhuhai, and analyzed for their volatile organic compounds (VOCs) composition. Source profiles of vapors of the vehicular fu- els used in these cities were constructed and are believed to be the first reported for the PRD region. The C 8-C10 hy- drocarbons were the main constituents of diesel. Different from diesel, gasoline used in the PRD region was mainly comprised of lighter C4-C7 hydrocarbons, with toluene and i-pentane being the two most abundant species. The toluene content in the Hong Kong and Macau gasoline samples were higher than that in Guangzhou and Zhuhai, while the re- verse was true for the benzene content. The benzene levels in Guangzhou and Zhuhai exceeded the maximum allowable benzene levels for Mainland China unleaded gasoline. Liq- uefied Petroleum Gas (LPG) samples were collected only in Hong Kong and were comprised mainly of n-butane, propane and i-butane. Traffic samples indicated that Evaporative Loss and vehicular combustion were the primary contributors to elevated VOC levels in roadside atmospheres. Significant i-pentane and toluene concentrations were observed in road- side atmospheres in all four cities. Ratio of i-pentane in gaso- line vapors to that in roadside samples were calculated and this showed that the degree of Evaporative Loss were higher in Guangzhou and Zhuhai than that in Hong Kong and Macau. We suggest the difference is due to the better maintenance and more new cars in Hong Kong and Macau. From tunnel samples collected in Hong Kong in two different years, we found that the relative amount of propane, i-butane, and n- butane increased between 2001 to 2003, consistent with the

  • Vehicular fuel composition and atmospheric emissions in South China: Hong Kong, Macau, Guangzhou, and Zhuhai
    Atmospheric Chemistry and Physics Discussions, 2006
    Co-Authors: W.-y. Tsai, L. Y. Chan, Donald R. Blake, K. W. Chu
    Abstract:

    Vehicular emission is an important source of air pollutants in urban cities in the Pearl River Delta (PRD) region of South China. In order to study the impact of Evaporative Loss of vehicular fuel on air quality, several commonly used fuel samples were collected in four main cities in the PRD region - Hong Kong, Guangzhou, Macau and Zhuhai, and analyzed for their volatile organic compounds (VOCs) composition. Source profiles of vapors of the vehicular fuels used in these cities were constructed and are believed to be the first reported for the PRD region. The C-8-C-10 hydrocarbons were the main constituents of diesel. Different from diesel, gasoline used in the PRD region was mainly comprised of lighter C-4-C-7 hydrocarbons, with toluene and i-pentane being the two most abundant species. The toluene content in the Hong Kong and Macau gasoline samples were higher than that in Guangzhou and Zhuhai, while the reverse was true for the benzene content. The benzene levels in Guangzhou and Zhuhai exceeded the maximum allowable benzene levels for Mainland China unleaded gasoline. Liquefied Petroleum Gas (LPG) samples were collected only in Hong Kong and were comprised mainly of n-butane, propane and i-butane. Traffic samples indicated that Evaporative Loss and vehicular combustion were the primary contributors to elevated VOC levels in roadside atmospheres. Significant i-pentane and toluene concentrations were observed in roadside atmospheres in all four cities. Ratio of i-pentane in gasoline vapors to that in roadside samples were calculated and this showed that the degree of Evaporative Loss were higher in Guangzhou and Zhuhai than that in Hong Kong and Macau. We suggest the difference is due to the better maintenance and more new cars in Hong Kong and Macau. From tunnel samples collected in Hong Kong in two different years, we found that the relative amount of propane, i-butane, and n-butane increased between 2001 to 2003, consistent with the 40% increase in LPG fueled vehicles. Propane to butanes ratios were calculated for LPG samples and tunnels samples, and the comparable ratios illustrated the LPG leakages from LPG fueled vehicles crossing the tunnel.

Ronny Schoenberg - One of the best experts on this subject based on the ideXlab platform.

  • Evaporative Loss of moderately volatile metals from the superheated 1849 ma sudbury impact melt sheet inferred from stable zn isotopes
    Earth and Planetary Science Letters, 2020
    Co-Authors: Balz S Kamber, Ronny Schoenberg
    Abstract:

    Abstract The retention of moderately volatile elements on the growing Earth remains a major uncertainty in models of terrestrial accretion. Large impactors were the main carriers of accreted material but their mutual energetic collisions and impacts onto the Earth also caused chemical fractionation for which limited experimental data exist. The objective of this work was to study several moderately volatile elements in the third-largest impact basin preserved on Earth at Sudbury, Ontario. We conducted a new chemostratigraphic transect ( n = 41 ) of Zn isotope ratios and concentrations by analysing melt sheet and basin fill samples. The data were compared to common Pb, Cs, Cd and Sb concentration systematics. Within the crystallised melt sheet there are strong trends in the extent of moderately volatile element deficits, Zn isotope composition ( δ 66 / 64 ZnJMC-L from 0.18 to 0.47‰) and initial Pb isotope composition. The combined evidence suggests that these trends reflect footwall contamination of a melt sheet that had experienced Evaporative Zn-Loss of up to 75–80%. Accounting for plausible isotopic signatures of target rocks, the maximum mass-dependent Zn isotope fractionation e was 0.29 ± 0.04‰ (1 s.d.), which translates to modest fractionation factors α = 0.99986 to 0.99975. This is comparable to melt fallout-glass and fused sands from nuclear detonation sites. We attribute the observed Zn Loss and isotope fractionation to the formation of the impact melt. The rapid formation of a solid lid of breccias upon seawater ingress may have prevented stronger Evaporative Loss and isotope fractionation. Within the crater fill, there is an up-stratigraphy increase in Zn isotope variability ( δ 66 / 64 ZnJMC-L from 0.29 to 1.05‰). Combined with evidence for biogenic reduced C, this suggests sedimentation of authigenic particulates within an enclosed crater sea. In the melt sheet, the Zn-Pb and Rb-Cs pairs experienced different extents of maximum Evaporative Loss (Pb up to 98.4% vs. Zn 78%; and Cs ∼90% vs. Rb ∼30%). The relative Loss pattern could reflect evaporation from superheated silicate melt at ∼1,450 °C and 1 atm. Loss from super-liquidus melts formed by bolide impacts could have been a significant process shaping the Earth's volatile and moderately volatile inventory.

Waiyan Tsai - One of the best experts on this subject based on the ideXlab platform.

  • vehicular fuel composition and atmospheric emissions in south china hong kong macau guangzhou and zhuhai
    Atmospheric Chemistry and Physics, 2006
    Co-Authors: Waiyan Tsai, L. Y. Chan, Donald R. Blake
    Abstract:

    Vehicular emission is an important source of air pollutants in urban cities in the Pearl River Delta (PRD) re- gion of South China. In order to study the impact of evapo- rative Loss of vehicular fuel on air quality, several commonly used fuel samples were collected in four main cities in the PRD region - Hong Kong, Guangzhou, Macau and Zhuhai, and analyzed for their volatile organic compounds (VOCs) composition. Source profiles of vapors of the vehicular fu- els used in these cities were constructed and are believed to be the first reported for the PRD region. The C 8-C10 hy- drocarbons were the main constituents of diesel. Different from diesel, gasoline used in the PRD region was mainly comprised of lighter C4-C7 hydrocarbons, with toluene and i-pentane being the two most abundant species. The toluene content in the Hong Kong and Macau gasoline samples were higher than that in Guangzhou and Zhuhai, while the re- verse was true for the benzene content. The benzene levels in Guangzhou and Zhuhai exceeded the maximum allowable benzene levels for Mainland China unleaded gasoline. Liq- uefied Petroleum Gas (LPG) samples were collected only in Hong Kong and were comprised mainly of n-butane, propane and i-butane. Traffic samples indicated that Evaporative Loss and vehicular combustion were the primary contributors to elevated VOC levels in roadside atmospheres. Significant i-pentane and toluene concentrations were observed in road- side atmospheres in all four cities. Ratio of i-pentane in gaso- line vapors to that in roadside samples were calculated and this showed that the degree of Evaporative Loss were higher in Guangzhou and Zhuhai than that in Hong Kong and Macau. We suggest the difference is due to the better maintenance and more new cars in Hong Kong and Macau. From tunnel samples collected in Hong Kong in two different years, we found that the relative amount of propane, i-butane, and n- butane increased between 2001 to 2003, consistent with the