Mirjana Čurlin

Assessing the quality of raw cotton knitted fabrics by their streaming potential coefficients

Raw cotton knitted fabrics of Greek, Indonesian, and Indian origin were investigated through surface characterization before and after processing. Surface modifications of all the knitted cotton fabrics were objectively evaluated through zeta potential measurements within a range of the electrolyte solution pHs, and swelling over time. Streaming potential coefficients of different cotton knitted fabrics were applied in order to establish a correlation between the properties of the raw and treated cotton knitted fabrics of different origins. The rate of swelling was calculated from the streaming potential coefficients of the raw knitted fabrics before and after different treatments. Swelling rate for different origins and different treatments of cotton knitted fabrics and the correlation coefficients were obtained using linear regression. Additionally, a data cluster analysis was performed in order to group different origins of cotton, while all the treatments were sorted according to zeta potential and the rate of swelling coefficients. The obtained results showed differences among the clusters, depending on the origin of the cotton knitted fabrics and treatments they were exposed to.

Analysis of diffusivity of the oscillating reaction components in a microreactor system

When performing oscillating reactions, periodical changes in the concentrations of reactants, intermediaries, and products take place. Due to the mentioned periodical changes of the concentrations, the information about the diffusivity of the components included into oscillating reactions is very important for the control of the oscillating reactions. Non-linear dynamics makes oscillating reactions very interesting for analysis in different reactor systems. In this paper, the analysis of diffusivity of the oscillating reaction components was performed in a microreactor, with the aim of identifying the limiting component. The geometry of the microreactor microchannel and a well defined flow profile ensure optimal conditions for the diffusion phenomena analysis, because diffusion profiles in a microreactor depend only on the residence time. In this paper, the analysis of diffusivity of the oscillating reaction components was performed in a microreactor equipped with 2 Y-shape inlets and 2 Yshape outlets, with active volume of V = 4 μL at different residence times.

Local sensitivity analysis and metabolic control analysis of the biological part of the BTEX bioremediation model

Environmental distribution and bioremediation of hydrocarbon pollutants is described in the literature with complex mathematical models. Better understanding and easier model application require detailed model analysis. In this work, local sensitivity analysis of the kinetic parameters and metabolic control analysis of the biological part of the integrated BTEX bioremediation model were performed. Local sensitivity analysis revealed that the dissolved oxygen concentration (SO) and particulate iron (III) oxide concentration (SFe) were the most sensitive to both positive and negative parameter value perturbations. In the case of model reactions, aerobic growth (r1) and aerobic growth on acetate (r13) were observed to be the most sensitive. The elasticity, flux control, and concentration control coefficients were estimated by applying the metabolic control analysis methodology. Metabolic control analysis revealed a positive effect of ammonium on all analysed model reactions. The results also indicated the importance of perturbation of the enzyme level catalysing iron reduction on acetate on model fluxes, as well as the importance of enzyme level catalysing aerobic growth on model metabolite concentration. These results can be used in planning optimal operating strategy for BTEX bioremediation.