This paper presents the results of experimental testing of parameters of the flow of an agitated liquid in a stirred tank with an eccentrically positioned shaft and with a Rushton turbine. The investigations were focused on the impact of the stirrer shaft shift in relation to the stirred tank vertical axis on the agitated liquid mean velocities and the liquid turbulent velocity fluctuations, as well as on the turbulence intensity in the tank. All the experiments were carried out in a stirred tank with the inner diameter of 286 mm and a flat bottom. The adopted values of the shaft eccentricity were zero (central position) and half the tank radius. The liquid flow instantaneous velocities were measured using laser Doppler anemometry.
In the paper the parametric optimization problem for a linear system with two delays and a PD-controller is presented. In the parametric optimization problem the quadratic performance index is considered. The value of the quadratic index of quality is calculated due to the Lyapunov functional and is equal to the value of that functional for the initial function of the neutral system with two delays. The Lyapunov functional is determined by means of the Lyapunov matrix.
In the paper a Lyapunov matrices approach to the parametric optimization problem of a time-delay system with two commensurate delays and a PI-controller is presented. The value of integral quadratic performance index is equal to the value of the Lyapunov functional for the initial function of the time-delay system. The Lyapunov functional is determined by means of the Lyapunov matrix. In the paper is presented the example of a scalar system with two delays and a PI controller.
The article discusses the book Zmiana perspektywy. Gawęda nie tylko językoznawcza [Change of perspective. More than a tale of linguistics] by Zuzanna Topolińska (Cracow 2015). The author of this text emphasizes that the word gawęda [tale] in the book’s subtitle is misleading, given that, despite the style of language used in the book, Topolińska discusses important issues of a linguistic and intercultural nature. In her short essays in the fi rst part of the book Topolińska addresses the organizational structure of philology studies in Poland and Macedonia, she confronts the Polish and Macedonian approach to the dialectgeneral language relationship, she talks about language standards, about the differences between politeness in Poland and Macedonia, as well as the attitude towards women and the outlook toward religion in both countries. In the second part of the book Topolińska takes up lexical issues, giving examples of how under the infl uence of spiritual culture certain words in Polish and Macedonian that derive from the same core have taken on a different meaning. The author of the article concludes that this short and very personal book by Topolińska fulfi lls its task and subsequently alters his view on the linguistic and non-linguistic world of the Slavs.