Stevan N. Blagojević

Numerical evidence of complex nonlinear phenomena of the Belousov-Zhabotinsky oscillatory reaction under batch conditions

By numerical calculations based on our previously proposed model with Br2O intermediate species we were able to simulate complex evolution of the Belousov-Zhabotinsky (BZ) reaction under batch conditions. In the defined region of initial malonic acid concentration [MA]0 (1.00 × 10−3 mol dm3 ≤ [MA]0 ≤ 1.50 mol dm−3) different sequences of regular and complex periodic and aperiodic oscillations were obtained. It is noticed that the bromine evaporation significantly affects the dynamics of the reaction.

Return map analysis of the highly nonlinear Bray–Liebhafsky reaction model

By numerically simulated Bray–Liebhafsky (BL) reaction under a continuously fed well stirred tank reactor (CSTR) conditions, we discussed the attractors and Poincaré 1D maps with respect to flow rate as the control parameter. The new technique of the return maps from transient trajectories over the slow manifold is developed and applied in order to explore its multilayered structure related to dynamical states (periodic and aperiodic -chaotic oscillating modes) of the system. Kinetic relations underlying the slow manifold structure are briefly discussed.

Synergism and Physicochemical Properties of Anionic/Amphoteric Surfactant Mixtures with Nonionic Surfactant of Amine Oxide Type

The physicochemical properties of initial formulation, that is anionic/amphoteric surfactants mixture SLES/AOS/CAB (sodium lauryl ether sulfate (SLES), α-olefin sulfonates (AOS) and cocamidopropyl betaine (CAB) at ratio 80 : 15 : 5) with nonionic surfactant of amine oxide type (lauramine oxide (AO)) in various concentration (1–5%) were studied. To characterize the surfactants mixture, the critical micelle concentration (CMC), surface tension (γ), foam volume, biodegradability and irritability were determined. This study showed that adding of AO in those mixtures lowered both γ and CMC as well as enhanced SLES/AOS/CAB foaming properties, but did not significantly affect biodegradability and irritability of initial formulation. Moreover, an increase in AO concentration has a meaningful synergistic effect on the initial formulation properties. All those results indicates that a nonionic surfactant of amine oxide type significantly improves the performance of anionic/amphoteric mixed micelle systems, and because of that anionic/amphoteric/nonionic mixture can be used in considerably lower concentrations as a cleaning formulation.