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In recent years there has been increasing research interest in the removal of nitrogen-oxides from exhaust gases using a pulsed corona discharge reactor. The pulsed streamer corona produces energetic electrons that excite, ionize and dissociate gas molecules, and by forming radicals that enhance the gas-phase chemical reactions which reduce the pollutant’s concentration.In this paper a method is presented, where the reaction rates of the electron-molecule collision are determined. The model is based on calculation of the energy of free electrons in the time and space varying field, considering the mean free path and the energy-dependent reaction cross sections of molecules. Knowing the rates, it is possible to solve the reaction kinetic equations, and to get the time-evolution of by-products, and the decomposition ratio of the pollutant gases.
Previous reports highlighted the onion solid wastes as abundant, residual material that might contain a significant load of antioxidant polyphenols. Although there have been studies pertaining to polyphenol recovery from onion wastes, the effect of temperature has not been adequately addressed. In this line, this study was undertaken with the aim of establishing a correlation between the extraction yield in total polyphenols and the extraction temperature, using acidified aqueous ethanol as the solvent system. Extraction of polyphenols from onion solid wastes was found to obey 2nd-order kinetics. On such a basis, the yield in total polyphenols at saturation could be very effectively determined and correlated with temperature using non-linear regression. The results indicated that the extraction yield at saturation is highly correlated with temperature, following a quadratic function. The extract obtained at optimal temperature (40 °C) had a total polyphenol yield of 21.10 mg gallic acid equivalents per gram of dry weight, and it was further analysed by liquid chromatography-mass spectroscopy to characterise its major constituents. The polyphenols detected were quercetin glucosides, as well as quercetin oxidation derivatives, including certain degradation products and dimers. The outcome of this study outlined that temperatures above 40 °C are rather not favourable for polyphenol extraction from onion solid wastes, as suggested by the model established through kinetics. The extract obtained under optimal conditions contained peculiar polyphenolic composition, not encountered in any other food processing residue.
With the aim to determine the influence of packaging in preserving the quality of wine, in this research project the chemical and sensorial evolution of a red wine stored in different packaging materials (glass bottles vs multilayer Tetrabriks®) has been evaluated over a period of 12 months. Furthermore, two different temperature levels (4 and 20 °C) for each packaging solution were maintained throughout the storage period.
The results show how the characteristics of packaging could deeply affect wine quality as a function of the storage conditions used, and suggest that with their rational optimization the quality of red wine during storage can be kept and its shelf life extended. In this context, the kinetic characterization of the time evolution of some chemical compounds that can be assumed as indexes of wine oxidation rate could enhance the consumer’s enjoyment during tasting.
Under the adopted experimental conditions, the rate of wine aging was higher when the storage temperature increased. Furthermore, after 12 months of storage at room temperature, the glass bottles generally better preserved red wine from oxidation than multilayer Tetrabriks®.
. This proposed controller structure will be employed in real-time applications of such systems. References [1] S. M. H. Mousakazemi and N. Ayoobian , “ Robust tuned PID controller with PSO based on two-point kinetic model and adaptive disturbance
Effects of the osmotic pre-treatment (OD) with sucrose or sorbitol solutions and different drying methods on the rehydration kinetics of apple cubes were studied. Samples were dried by hot air (HAD) at 70 ºC, by microwave (MWD) at 500 W, and by freeze-drying (FD). The rehydration of dried samples was performed in water at 80 ºC and at a mass ratio of sample to water of 1:100. The first order kinetic model was found to provide the best fit of the rehydration data. The pre-treatment and the drying method did not affect the rehydration kinetics, but the rehydration capacity after 12 min of rehydration was higher in the control samples than in the osmotically dehydrated ones, for all three drying methods. The rehydration rate and the rehydration capacity of the apple cubes dried by HAD, MWD, or FD were not affected by the solute used in the pre-treatment, sucrose and sorbitol.
-Orozco, J. A., Fernandes-Conde, C., Peinado, J. M. & Garcia-Ochoa, F. (1998): A kinetic model for beer production under industrial fermentation conditions. Math. Comput. Simulat , 48 , 65-74. A kinetic model for beer production
Shishkova I. N., Sazhin S. S. A numerical algorithm for kinetic modeling of evaporation processes, J. Computational Physics , Vol. 218, 2006, pp. 635–653. Sazhin S. S. A numerical
Rodrigez-Fernandez, M., Cardelle-Cobas, A., Villamiel, M. & Banga, J.R. (2011): Detailed kinetic model describing new oligosaccharides synthesis using different β-galactosidases. J. Biotechnol., 153, 116
analysis was limited to batch configuration ( Kashyap et al., 2015 ). The purpose of this communication is to provide a mathematical description of the biocatalytic behavior of Pectinex Ultra SP-L. We formulate kinetic models that describe FOS production in
mechanism of RW biomass' components The integral master-plots have been used to reveal and to estimate the kinetic models f(x) for hemicellulose, cellulose and lignin's RW biomass components. Figures 10–12 show the plot of experimental and theoretical
