Papers by Author: Lj. Kolar-Anić

Abstract: This work presents the current oscillation phenomena observed in an electrochemical Cu/0.5 M CF3COOH system. The dynamical response of this new oscillator was followed by both current density-potential (j-E) and current density-time (j-t) curves. The current oscillation phenomena of the investigated system were monitored over various potential scan rates and constant applied potentials as control parameters. The increase of potential scan rate significantly decreases both the potential range of current oscillations and the frequency of oscillations. At the j-t curves both the simple and the complex (period adding) oscillations were found. Moreover, with the increase of applied potential, the increase of period of oscillations and current oscillation amplitudes were observed. It appears that the period of current oscillations exponentially grows with applied potential.

Abstract: Macroporous cross-linked copolymer of 4-vinylpyridine and 25% (4:1) divinylbenzene is analyzed under open conditions, that is in a continuous well-stirred tank reactor (CSTR). With this aim the appropriate bifurcation diagram is found and the behavior of the system with and without polymer in the vicinity of the bifurcation point is used for the polymer examinations. Two different granulations of polymer are considered. Moreover, some physicochemical characteristics of the polymer, such as specific surface area, skeletal and particle density, are determined.

Abstract: The thermogravimetric analysis of superabsorbing polyacrylic hydrogel dehydration, performed under non-isothermal conditions at different heating rates was discussed. Particularly, the influence of the heating rate on the obtained results is given in detail. For this purpose the Weibull distribution function was applied. The thermogravimetric curve when the heating rate tends to zero was evaluated. The activation energy E = 63 kJ/mol, pre-exponential factor A = 2.97 × 108 min−1, and rate constant k = 2.76 × 10−3 min−1 were determined on the basis of this curve.