The relevance of this research work is due to the fact that farms and other farms are located at a considerable distance from sources of centralized power supply. Therefore, it is necessary to introduce autonomous generators as the main units that ensure the uninterrupted functioning of energy systems. The purpose of this research work is to analyze the features of the functioning of an autonomous constant voltage generator, as well as to determine the basic physical laws that are of fundamental importance in its operation. The basis of the methodological approach in this scientific study is a combination of methods of system analysis with an analytical study of the general principles of operation of such devices, which are of fundamental importance from the point of view of ensuring the proper level of operational reliability. The main results obtained in this research work should be considered the definition of equations for calculating the instantaneous values of the three-phase excitation current, as well as the peak value of the three-phase excitation current of an autonomous constant voltage generator. The results obtained in the course of this scientific research and the conclusions formulated on their basis are of fundamental importance for developers of modern technological systems, including autonomous constant voltage generators, as well as for employees of technological services of modern industrial enterprises, whose professional responsibility includes the practical operation of such devices to solve a complex of technical tasks facing these enterprises.

Open pit mining of rock minerals and the affected areas requiring further development are a serious challenge for shaping the positive image of the mining industry among the public. The direction and method of post-mining land reclamation are important for this image, which should take into account various factors describing the mining area, including social preferences. The article presents an example solution – fuzzy system (FSDR) – which supports the selection of the direction of reclamation of post-mining areas created after the termination of operations of open pit gravel and sand natural aggregate mines. The article presents selected factors determining the selection of the direction and possible reclamation variants as input and output data of the fuzzy system. The rules base of the developed system, as well as the mechanisms of inference and defuzzification, were also characterized. The application of the developed system is presented on selected examples.

The objective of this research was to estimate the content of 16 PAHs (US EPA list) in plants (com and willow) cultivated in sewage sludge-amended soil. An ultrasonic method and dichloromethane have been used to extract total PAHs content. The solid phase extraction was performed to purify sample extracts. HPLC and UV detection were employed to separate and quantify the studied PAHs. On the basis of the obtained results a bioconcentration factor was calculated. The contents of 16 PAH in plants ranged from 5.83 to 33.8 μg/kg d.m., with a dominant share of low molecular weight PAHs. The application of sewage sludge caused an increase in the PAH content in plants in relation to the dose applied. However, even the highest doses of sewage sludge did not led to the increase of PAI-ls content in plants above the level which may be hazardous for human health. The bioconccntration factors were on the level notted by others authors and ranged from 0.04 to 0.38 for the sum of 16 PAH.

The paper analyses the influence of seasonal temperature variations on fatigue strength of flexible and semi-rigid pavement structures chosen for KR4 traffic flow category. The durability of pavement determined assuming a yearly equivalent temperature of 10˚C and assuming season-dependent equivalent temperatures was compared. Durability of pavement was determined with the use of Asphalt Institute Method and French Method. Finite Element Method was applied in order to obtain the strain and stress states by the means of ANSYS Mechanical software. Obtained results indicate a considerable drop in pavement durability if seasonal temperature variations are considered (up to 64% for flexible pavements and up to 80% for semi-rigid pavements). Durability obtained by the French Method presents lower dependence on the analysed aspect.

This paper seeks to acquaint the readers with problems related to Wojciech Kętrzyński’s 1893 edition of Epitaphium Dithardi abbatis [ Epitaph of abbot Dithard] in volume six of Monumenta Poloniae Historica. In contrast to the information the scholar disseminated which was subsequently commonly adopted, Epitaphium Dithardi abbatis was not a part of the hand-written collection of the so-called Oliva sources ( Fontes Olivenses). This laudatory work in a verse form, in honour of the first abbot of the Oliva monastery, was probably created in the 13th century, and today is known mainly from the 17th-century epitaph tablet surviving in the Oliva Cathedral in Gdańsk, which Wojciech Kętrzyński did not see personally. He issued Epitaphium Dithardi abbatis taking as the basis a copy of the text surviving in the Kórnik manuscript call no. BK 65, copied from this tablet in 1749. Today, in view of the existence of an older copy of the text, included in the Gdańsk manuscript (APG, call no. 940/422) copied not from the tablet but from the 15th-century polychrome, Kętrzyński’s edition should be considered insufficient.