The aim of the paper is to explore the process of r obstruentisation which can be found in Polish in the ‘trapped’ context, i.e. between two obstruents or at the end of the word after an obstruent. More specifi cally, in order to explain the mechanics of the [r] > [/] shift, the author looks at the phenomenon of sonorant devoicing and some historical facts concerning the development of r. Since r obstruentisation can also be found in a closely related Czech, the data from both languages are confronted and discussed. The solution offered here is based on the analysis of w obstruentisation proposed by Cyran and Nisson (1998).

In 2002 the circulation of nutrients and their balance was studied in a large, shallow, eutrophic Lake Gardno. It was determined that throughout a year 1516 Mg of total nitrogen and 155 Mg of total phosphorus reach the lake. Approximately 67% of nitrogen and 87% of phosphorus reaching the lake flows out of it, the rest remains in the lake. About 45% of the total loss of nitrogen results from denitrification, and about 53% from sedimentation. The greatest effect on the circulation of nutrients in Lake Gardno is exerted by the mixing of water caused by strong winds resulting in the upward movement of the surface layers of bottom sediments. This causes increased resuspension and sedimentation, which mask similar processes resulting from the outer load of nutrients and from autochtonie processes and products, which are one or two orders ofa magnitude smaller.

The paper presents a photographic analysis of the break-up of gas bubbles flowing out of the outlets of a self-aspirating disk impeller. It was found that bubbles detached from the interfacial surface most often disintegrate to form several daughter bubbles. Further in the work, the population balance model was verified for several formulas describing the bubble break-up rate. It has been found that a good fit to the experimental data is provided by the formula given by Laakkonen for 5 daughter bubbles. The possibility of using the Monte Carlo method to model the bubble break-up processwas also determined. For this method, a good agreement of results was achieved for the division into a maximum of 10 daughter bubbles. In the case of this method it was also found necessary to use the function of break-up frequency at a higher rate for smaller bubbles.

Transformers are one of the most important components of the power system. It is important to maintain and assess the condition. Transformer lifetime depends on the life of its insulation and insulation life is also strongly influenced by moisture in the insulation. Due to importance of this issue, in this paper a new method is introduced for determining the moisture content of the transformer insulation system using dielectric response analysis in the frequency domain based on artificial bee colony algorithm. First, the master curve of dielectric response is modeled. Then, using proposed method the master curve and the measured dielectric response curves are compared. By analyzing the results of the comparison, the moisture content of paper insulation, electrical conductivity of the insulating oil and dielectric model dimensions are determined. Finally, the proposed method is applied to several practical samples to demonstrate its capabilities compared with the well-known conventional method.

Field investigations concerning screw piles and columns have been carried out for the “Bearing capacity and work in the soil of screw piles” research project, financed by the Polish Ministry of Science and Higher Education – project No N N506 369234. The tests of three instrumented screw piles were conducted together with CPTU tests and measurements of pile installation parameters (especially torque). The objectives of field investigations and the entire research project include discovering how screw piles work in the soil, locating and describing the correlations between CPTU results and rotation resistance during pile auger installation and next establishing correlations between CPTU results, rotation resistance and the bearing capacity of this kind of piles. The paper describes the investigation procedure and the basic results of tests carried out in the first of a series of sites.

Author explains a necessity of supply optimization to construction sites with small storage areas. This paper takes account of conditions existing in Poland. From among all factors discussed by the author, first of all, we should point at construction works on plots located in densely built-up areas, obtained by demolition of existing buildings, as well as a necessity of plots utilization after demolished buildings that technical conditions do not allow for further exploitation.

To accept science as a tool of cognition of this what is unknown, and teaching which serves popularization of knowledge in society, the scientific committees of PAS should integrate scientists within the Country and on the background of world science progress. However, scientific associations should propagate their field knowledge and join and consolidate researchers and people within the area of their interest. To realize this, the scientific committees must represent all scientific centers in our Country and all research directions and so called schools of research. Because of this, the procedure of election of the committees’ representatives has to be changed.