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ABSTRACTVehicle deterioration and technological change influence emission factors (EFs). In this study, the impacts of vehicle deterioration and emission standards on EFs of regulated pollutants (carbon monoxide [CO], hydrocarbon [HC], and nitrogen oxides [NOx]) for gasoline light-duty trucks (LDTs) were investigated according to the inspection and maintenance (I/M) data using a chassis dynamometer method. Pollutant EFs for LDTs markedly varied with accumulated mileages and emission standards, and the trends of EFs are associated with accumulated mileages. In addition, the study also found that in most cases, the median EFs of CO, HC, and NOxare higher than those of basic EFs in the International Vehicle Emissions (IVE) model; therefore, the present study provides correction factors for the IVE model relative to the corresponding emission standards and mileages.Implications: Currently, vehicle emissions are great contributors to air pollution in cities, especially in developing countries. Emission factors play a key role in creating emission inventory and estimating emissions. Deterioration represented by vehicle age and accumulated mileage and changes of emission standards markedly influence emission factors. In addition, the results provide collection factors for implication in the IVE model in the region levels.

Series of bi-component nonylphenol alkyl sulfonate surfactants (C12/Cn-NPAS, n= 8, 10, 14, 16) were synthesized through sulfonation-alkylation-neutralization using a mixture of linear alpha olefin (C12-olefin and Cn-olefin, n= 8, 10, 14, 16), SO3and nonylphenol as raw materials. The effect of the raw materials composition on the properties, such as surface tension, interfacial tension, wettability, foam properties of the prepared C12/Cn-NPAS (n= 8, 10, 14, 16) surfactants was systematically investigated. The critical micelle concentrations (CMC) of C12/C8-NPAS, C12/C10-NPAS, C12/C14-NPAS and C12/C16-NPAS are 0.42, 0.26, 0.22 and 0.40 mmol · L-1, and surface tensions at CMC (?CMC) are 34.7, 27.9, 31.8 and 33.3 mN · m-1, respectively. Compared with SDBS and HABS, the surface properties of the prepared C12/Cn-NPAS are superior to traditional surfactants. Interfacial tension between Daqing crude oil and weakly alkaline ASP oil flooding system containing 0.1 wt% of C12/C14-NPAS could reach an ultralow level of 9.78 × 10-3mN · m-1, which is lower than that for C12-NPAS and HABS. C12/C10-NPAS shows better wetting performance and foamability and foam stability than other synthesized surfactants.

A series of novel dialkyl disulfonate Gemini surfactants (Cn-GSBS, n = 8, 12, 14, 16, n is the carbon number of the hydrophobic chain) was synthesized from cyanuric chloride, aliphatic amine, ethylenediamine, N,N'-dimethyl-1,3-propyldiamine and sodium 2-chloroethanesulfonate. The chemical structures of the prepared compounds were confirmed by FT-IR and 1H NMR. The critical micelle concentrations (CMC) in aqueous solutions at 25°C were determined by surface tension method. The CMC value decreased with increasing length of the carbon chain. The CMC reached a minimum as low as 5 × 10-5mol · L-1for C16-GSBS. The interfacial tensions (IFT) between Daqing crude oil and Cn-GSBS surfactant solutions were also measured. The effects of the concentration of Na2CO3, the concentration and carbon chain length of Cn-GSBS on the IFT of crude oil-water were investigated in detail. The results show that, for the aqueous surfactant system containing the weak base Na2CO3, oil-water interfacial tension can be reduced to 10-2mN m-1orders of magnitude. The results also indicate that with the increase of surfactant concentration and the chain length, the oil-water interfacial tension decreased markedly, which indicates that Cn-GSBS surfactants have a good interface activity. These surfactants are good candidates for weak base-surfactant-polymer EOR process.