Recent dynamic changes in global fossil fuels markets and the European carbon dioxide emission allowances system have significantly impacted the energy sectors. These fluctuations also influence district heating (DH) markets where coal and natural gas remain dominant energy vectors in numerous European countries. District heating markets are distinct from other commodity markets due to their local nature and distribution requirements. Consequently, they can operate under various market models and have different price design policies depending on the country and region. With these considerations, this study aims to review and analyse the current market models and regulations of price formulation in the context of final prices in selected district heating markets. The primary objective is to conduct an in-depth analysis of the key district heating markets in Poland and compare the outcomes with the markets of neighbouring countries, including the Czech Republic, Slovakia, Lithuania, Latvia, Estonia, and Germany. Poland is taken as an example due to its high dependence on fossil fuels and its vulnerability to current global price fluctuations. The results indicate that Poland has one of the most regulated district heating markets, and these regulations can impact the profitability of district heating companies with high prices of fuel and carbon certificates observed in global markets. To create incentives for potential investors and incumbent companies to develop more sustainable and low-emission district heating markets in Poland – where energy transition processes are still underway – it is recommended to increase the frequency of formulation and approval of tariffs.

The work concerns dynamic similarity criteria of various phenomena occurring in hydraulics and fluid dynamics originally derived from ratios of forces and forces moments affecting these phenomena. The base of dynamic similarity criteria formulations and considerations is A. Flaga’s method and procedure for determining dynamic similarity criteria in different issues of fluid–solid interactions i.e. at different fluid–solid relative motions. The paper concerns the determination and analysis of dynamic similarity criteria for various practical problems encountered mainly in hydraulics and fluid dynamics at steady, smooth fluid onflow in front of a solid. Moreover, the cases of mechanically induced vibrations of a body in a stationary fluid moving with constant velocity in front of the body have been presented. Assuming authorial method and procedure for determining dynamic similarity criteria, its have been presented and analysed in the paper both well known similarity numbers obtained in another way (e.g. from dimensional analysis or differential equations for particular problems – as Reynolds, Froude, Euler, Cauchy, Strouhal, Mach numbers) – as well as several new similarity numbers encountered in different fluid solid interaction problems (e.g. new forces and moments coefficients encountered in problems of vibrating solid bodies in fluids).

In 2016–2018 Google ran a special fund to support innovation in European journalism. This article is based on the analysis of over 600 descriptions of successful projects from the Google Digital News Initiative website. The aim of the survey was to get the picture of the digital innovations implemented in the framework of competing projects and to find out whether the language of the descriptions reveals how the participants define their vision of digital innovations in journalism.