Studying the sensitivity of pollutants’ concentrations caused by variations of chemical rates

A systematic procedure for sensitivity analysis of a case study in the area of air pollution modeling has been performed. Contemporary mathematical models should include a large set of chemical and photochemical reactions to be established as a reliable simulation tool. The Unified Danish Eulerian Model is in the focus of our investigation as one of the most advanced large-scale mathematical models that describes adequately all physical and chemical processes.Variance-based methods are one of the most often used approaches for providing sensitivity analysis. To measure the extent of influence of the variation of the chemical rate constants in the mathematical model over pollutants’ concentrations the Sobol’ global sensitivity indices are estimated using efficient techniques for small sensitivity indices to avoid a loss of accuracy. Studying relationships between input parameters and the model’s output as well as internal mechanisms is very useful for a verification and an improvement of the model and also for development of monitoring and control strategies of harmful emissions, for a reliable prediction of the final output of scenarios when the concentration levels of pollutants are exceeded. The proposed procedure can also be applied when other large-scale mathematical models are used.     

Unified retention index of hydrocarbons separated on dimethylsilicone OV-101

Summary Gas chromatographic retention indices of 51 hydrocarbons were determined on OV-101 dimethylsilicone between 40 and 70°C. From the measured data the unified retention indices were calculated.     

Kinetics of water vapor adsorption by ion exchange polyacrylonitrile fibres

Kinetics of water vapor adsorption by ion exchange PAN fibres has been studied. Adsorption can be described by an exponential kinetic equation. Experimental results permit the assumption that the surface of the materials studied behaves as uniformly nonhomogeneous with more strongly expressed entropy nonhomogeneity, connected with cross-linking of the modified fibres. The dependence between the kinetic characteristics and the solubility of the materials in DMF shows that the main factor affecting unfavorably the adsorption kinetics is cross-linking. Increase of N-containing anion exchange groups reduces the effect of adsorption delay due to cross-linking.

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Micromechanics of residual saturation formation during immiscible displacement in a porous medium

The process of displacement of a nonwetting fluid has been studied experimentally on a transparent model of a porous medium for various percolation velocities in the stable front regime, when the viscosity of the displacing fluid is greater than that of the fluid displaced. The flow structures in the final displacement regime, when the nonwetting phase is distributed in the pore space in the form of individual drops or ganglia, have been visually investigated. Imbibition is numerically modeled on a two-dimensional network model with allowance for various microdisplacement mechanisms. The effect of the initial displacing phase saturation on the magnitude and structure of the residual displaced fluid saturation is demonstrated. The fractal dimensionality of the displacement boundary is measured.Novosibirsk. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.3, pp. 116–121, May–June, 1994.     

Quantitative analysis of resorcinol,quinol and cathechol by IRT-method

In the present paper the determination of resorcinol(I), quinol(II) and catechol(III) in mixture is demonstrated by IRT method using nonsophisticated IR spectrophotometer. The sample dissolved in acetone is poured in the sample cell. The absorbances at 963 cm^?1 (I), 829 cm^?1 (II) and 745 cm^?1 (III) are consecutively compensated by titration of pure acetone in the reference cell with solutions of I,II,III respectively. The accuracy obtained is 1,5 %, 4,7 % and 10 % rel. The method is applied for quatitative investigation of reactionary mixtures containing resorcinol and quinol.     

Correlation equations for prediction of gas chromatographic separation of hydrocarbons on squalane

Summary The retention index of several hydrocarbon classes on squalane was found to be predictable (within two index units) with help of a physico-chemical index and a correction-structural number. A large number of structural elements were examined by means of correlation analysis and regression equations were obtained for calculation of the structural number. The multinomial regression equations were simplified by combining in one factor the important structural elements. A set of a limited number of selected representatives for every hydrocarbon class was found to give reliable estimations for the regression coefficient equations.     

Wechselwirkung zwischen Polyäthylenoxid und Fluorenyl-Alkalimetall-Verbindungen in Tetrahydrofuran

Ohne Zusammenfassung     

Gas chromatographic separation of ethanolamines and ethylene glycols without preliminary derivatization

Summary An effective and rapid GC separation of ethanolamines, even in the presence of ethylene glycols, using short glass capillary columns is developed. No preliminary derivatisation of the sample is necessary. The separation is completed in 6 minutes.