Hydraulic fracturing of rocks boosts the production rate by increasing the fracture-face surface area through the use of a pressurized liquid. Complex stress distribution and magnitude are the main factors that hinder the use of information gathered from in situ hydraulic fracturing in other locations. Laboratory tests are a good method for precisely determining the characteristics of these processes. One of the most important parameters is breakdown pressure, defined as the wellbore pressure necessary to induce a hydraulic fracture. Therefore, the main purpose of this investigation is to verify fracture resistance of rock samples fractured with the assistance of the most popular industry fluids. The experiments were carried out using a stand designed specifically for laboratory hydraulic fracturing. Repeatable results with a relative error within the range of 6-11% prove that the experimental methodology was correct. Moreover, the obtained results show that fracturing pressure depends significantly on fluid type. In the case of a water test, the fracturing pressure was 7.1±0.4 MPa. A similar result was achieved for slickwater, 7.5±0.7 MPa; however, a much lower value (4.7±0.5 MPa) was registered in the case of carbon dioxide.

The changes in the paralinguistic (social, economic, cultural) and linguistic sphere influence the quantitative and qualitative changes in a categorically diversified onomastic resource and the communicative flow of its elements on three levels of linguistic contact — nationwide, local and individual. The flow is additionally determined in the sphere of spontaneous everyday communication and in higher communicative functions (official linguistic behaviour). The accumulation of determinants which allow the usage of appropriate names and appellative forms (official and unofficial, e.g. diminutives, feminisms) involves the application of cumulative research methods, including psycho-, socio- and pragmalinguistic description of proper names functioning in communication. The contemporary theory of discourse in its three dimensions — formal, functional and interactional gives this possibility. It also requires the constant specification and standardization of Neoslavonic onomastic terminology.

The article describes the finds of six Roman coins and a mysterious object with an Arabic legend discovered in the years 2000–2014 at the bottom of Lake Turawskie, created in 1939. With the creation of the reservoir many archaeological sites (of varied chronology, from the Roman period to the late Middle Ages) were flooded, many of which could not be properly investigated due to the time pressure. The Roman coins presented here are a standard part in the overall image of coins discovered in Silesia. The mysterious object with an Arabic legend is unique, it has partial analogies in Norman weights or early-Arab coins (al-wafā lillāh coinage).