The paper analyses influences of the temperature and hydrophilic groups on micellar properties of ionic surfactants with 12-carbonic hydrophobic chains. The aim is to assess the impact of hydrophilic groups and temperature on thermodynamic parameters and micellization. This knowledge is indispensable for the formulation of new dosage forms. The method uses conductometric measurements. The following hydrophilic groups are analyzed: trimethylammonium bromide, trimethylammonium chloride, ethyldimethylammonium bromide, didodecyldimethylammonium bromide, pyridinium chloride, benzyldimethyl-ammonium chloride, methylephedrinium bromide, cis and trans-[(2-benzyloxy)-cyclohexyl-methyl]-N, N-dimethylammonium bromide, sodium sulphate and lithium sulphate. Except for a few cases, there is a good agreement between values of critical micellar concentrations (CMC) and critical vesicle concentration (CVC) obtained here and those which were obtained by other authors and/or by other physicochemical methods. Values of the CMC are compared with respect to the molar masses of hydrophilic groups. It was found that CMC values increased non-linearly with increasing system temperature. The degrees of counterion binding and thermodynamic parameters, like the standard molar Gibbs energy, enthalpy and entropy of micellization are determined and discussed in detail. The results obtained will be incorporated into in silico processes of modeling and design of optimal dosage forms, a current interdisciplinary research focus of the team.

In this article, the results of pressure coefficient on the atypical object obtained by experimental measurements in a boundary layer wind tunnel (BLWT) of Slovak University of Technology in Bratislava (STU) and computational fluid dynamics simulation (CFD) are presented. The pressure coefficient is one of the most important parameters expressing the wind pressure distribution on the structure. The loading by wind can only be acquired by execution of detailed tests and numerical analyses [1].

Knowledge of the release kinetics together with its (mathematical) model is inevitable for prediction of properties and optimization of dosage forms. The ability to optimize the release kinetics is a key factor in the endeavour of increasing pharmaceutical availability. The optimization may be done by a suitable choice of the dosage form or by clever distribution of the drug in the auxiliary substances or even by using an automatically working drug delivery device. This paper describes a model-based analysis and preparation of hydrogels. The following composition was used in the experiment: Chitosan – the gel creating basis; polymer, chlorhexidine – the drug; dodecyltrimethylammonium bromide – the auxiliary substance and surfactant. The release kinetics were studied at three temperatures and were evaluated by using several models (zero order, pseudo-first order, first order, Higuchi, Hixon Crowell, Weibul distribution and Korsmeyer-Peppas). It was found that the best fitting model of the drug release was the Higuchi model. So as to predict character of the release process (exothermic and spontaneous), the activation energy, activation enthalpy, entropy and Gibbs free energy were evaluated.

Abstract. The work was focused on modelling of cracks and simulations of their propagation in timber beams. The aim was to find out the influence of flaws on load-carrying capacity. In beam design and beam inspection, it is necessary to determine the load

This article describes the effect of inclination of columns on the change of stiffness of high-rise buildings with circular floor plan. Analysis was made for the building loaded by forces induced by wind and seismic loads. Various high-rise buildings with columns with different inclinations and buildings with vertical columns were analyzed from the viewpoint of horizontal displacements. The results were compared. The comparison was made with horizontal displacements of the building, where columns were inclined.