RESUMO
Independent component (IC) analysis was applied to near-infrared spectroscopy for analysis of gentiopicroside and swertiamarin; the two bioactive components of Gentiana scabra Bunge. ICs that are highly correlated with the two bioactive components were selected for the analysis of tissue cultures, shoots and roots, which were found to distribute in three different positions within the domain [two-dimensional (2D) and 3D] constructed by the ICs. This setup could be used for quantitative determination of respective contents of gentiopicroside and swertiamarin within the plants. For gentiopicroside, the spectral calibration model based on the second derivative spectra produced the best effect in the wavelength ranges of 600-700 nm, 1600-1700 nm, and 2000-2300 nm (correlation coefficient of calibration = 0.847, standard error of calibration = 0.865%, and standard error of validation = 0.909%). For swertiamarin, a spectral calibration model based on the first derivative spectra produced the best effect in the wavelength ranges of 600-800 nm and 2200-2300 nm (correlation coefficient of calibration = 0.948, standard error of calibration = 0.168%, and standard error of validation = 0.216%). Both models showed a satisfactory predictability. This study successfully established qualitative and quantitative correlations for gentiopicroside and swertiamarin with near-infrared spectra, enabling rapid and accurate inspection on the bioactive components of G. scabra Bunge at different growth stages.
RESUMO
In view of energy shortage and air pollution, ethanol-gasoline blended fuel used for motorcycle engine was studied in this work. The emissions of carbon monoxide (CO), nitrogen oxides (NO(X)) and engine performance of a 125 cc four-stroke motorcycle engine with original carburetor using ethanol-gasoline fuels were investigated. The model of three-variable Box Behnken design (BBD) was used for experimental design, the ethanol blend ratios were prepared at 0, 10, 20 vol%; the speeds of motorcycle were selected as 30, 45, 60 km/h; and the throttle positions were set at 30, 60, 90 %. Both engine performance and air pollutant emissions were then analyzed by response surface method (RSM) to yield optimum operation parameters for tolerable pollutant emissions and maximum engine performance. The RSM optimization analysis indicated that the most suitable ethanol-gasoline blended ratio was found at the range of 3.92-4.12 vol% to yield a comparable fuel conversion efficiency, while considerable reductions of exhaust pollutant emissions of CO (-29 %) and NO(X) (-12 %) when compared to pure gasoline fuel. This study demonstrated low ethanol-gasoline blended fuels could be used in motorcycle carburetor engines without any modification to keep engine power while reducing exhaust pollutants.
