A detailed chemical mechanism to describe the combustion of natural gas in internal combustion （IC） engine has been developed,which is consisting of 233 reversible reactions and 79 species.This mechanism accounts fo...A detailed chemical mechanism to describe the combustion of natural gas in internal combustion （IC） engine has been developed,which is consisting of 233 reversible reactions and 79 species.This mechanism accounts for the oxidation of methane,ethane,propane and nitrogen.It has been tested using IC engine model of CHEMKIN 4.1.1 and experimental measurements.The performance of the proposed mechanism was evaluated at various equivalence ratios （φ=0.6 to φ=1.3）,initial reactor conditions （Tini=500 to 3500 ℃; Pini=1.0 to 10 atm） and engine speed （2000-7000 rpm）.The proposed kinetic mechanism shows good concordances with GRI3.0 mechanism especially in the prediction of temperature,pressure and major product species （H2O,CO2） profiles at stoichiometric conditions （φ=1.0）.The experimental results of measured cylinder pressure,species fractions were also in agreement with simulation results derived from the proposed kinetic mechanism.The proposed mechanism successfully predicts the formation of gaseous pollutants （CO,NO,NO2,NH3） in the engine exhaust.Although there are some discrepancies among each simulation profile,the proposed detailed mechanism is good to represent the combustion of natural gas in IC engine.展开更多
A number of species （organic and inorganic） in airborne particulates cause the toxicity to living being. The potential of in vitro test methods were explored for toxicity assessment of trace toxic elements （inorgan...A number of species （organic and inorganic） in airborne particulates cause the toxicity to living being. The potential of in vitro test methods were explored for toxicity assessment of trace toxic elements （inorganic species） present in ambient air on human being （lungs）. A year long sampling of airborne particles （PM2.5） was carded （April 2008 to March 2009） in Lahore, Pakistan. A total of thirty nine samples were collected on 47 mm Zefiuor Teflon filter membranes and each was analysed to characterize for the elements： Sb, As, Be, Cd, Cr, Co, Pb, Mn, Hg using ICP-MS in water extract and total acid digestate. The samples cytotoxicity was also established using lung derived cells and MTS colorimetric assays. This generated dose response curves and IC50 values for the elemental mixtures identified on the Teflon filter membrane. The results indicated that even at low concentrations airborne elemental mixtures displayed an additive toxic effect.展开更多
文摘A detailed chemical mechanism to describe the combustion of natural gas in internal combustion （IC） engine has been developed,which is consisting of 233 reversible reactions and 79 species.This mechanism accounts for the oxidation of methane,ethane,propane and nitrogen.It has been tested using IC engine model of CHEMKIN 4.1.1 and experimental measurements.The performance of the proposed mechanism was evaluated at various equivalence ratios （φ=0.6 to φ=1.3）,initial reactor conditions （Tini=500 to 3500 ℃; Pini=1.0 to 10 atm） and engine speed （2000-7000 rpm）.The proposed kinetic mechanism shows good concordances with GRI3.0 mechanism especially in the prediction of temperature,pressure and major product species （H2O,CO2） profiles at stoichiometric conditions （φ=1.0）.The experimental results of measured cylinder pressure,species fractions were also in agreement with simulation results derived from the proposed kinetic mechanism.The proposed mechanism successfully predicts the formation of gaseous pollutants （CO,NO,NO2,NH3） in the engine exhaust.Although there are some discrepancies among each simulation profile,the proposed detailed mechanism is good to represent the combustion of natural gas in IC engine.
文摘A number of species （organic and inorganic） in airborne particulates cause the toxicity to living being. The potential of in vitro test methods were explored for toxicity assessment of trace toxic elements （inorganic species） present in ambient air on human being （lungs）. A year long sampling of airborne particles （PM2.5） was carded （April 2008 to March 2009） in Lahore, Pakistan. A total of thirty nine samples were collected on 47 mm Zefiuor Teflon filter membranes and each was analysed to characterize for the elements： Sb, As, Be, Cd, Cr, Co, Pb, Mn, Hg using ICP-MS in water extract and total acid digestate. The samples cytotoxicity was also established using lung derived cells and MTS colorimetric assays. This generated dose response curves and IC50 values for the elemental mixtures identified on the Teflon filter membrane. The results indicated that even at low concentrations airborne elemental mixtures displayed an additive toxic effect.
