The aim of this research was to present the changes in biomass production, especially pellets in Poland, in the context of world’s and European Union’s (EU) climate and energy policy, compared to other renewable energy sources. We also analyzed the law concerning the biomass production in the EU. Finally, we have elaborated the prognosis of the pellet production on the world scale. We have used different methods to achieve the goals, among which the most important are the Generalized Autoregressive Conditional Heteroscedasticity (GARCH model) and prognosis. We also compared the results of pellet production in different countries in the European Union. The results were presented in tabular and graphic form. We have received the data from Eurostat and the Main Statistical Office (MSO) in Poland. Our research proves the increase of biomass and pellet production on the global scale. Moreover, global wood pellet production increased by 972% in the years 2005–18. We can conclude that this increase was the result of increasing demand for renewable energy sources. The first research hypothesis assumed that the changes in the European Union Policy have impacted the increase of biomass production in the world. Our prognosis confirmed the second hypothesis that the development of pellets will increase as the result of increasing global demand. The use of more renewable energy sources is necessary to decrease the degradation of the environment.

The main aim of this paper was to determine changes in renewable energy production in the countries of Central and Eastern Europe. The specific objectives were to assess the degree of concentration of renewable energy and the pace of changes in the volume of production of this energy from individual sources in the countries of Central and Eastern Europe, as well as to determine the structure according to renewable energy sources to show the directions of changes. Central and Eastern Europe countries were covered in the research, meaning that a total of 23 countries were included in the analysis. The data used in the study was obtained from the IRENA and World Bank databases. The research period covered the years from 2011 to 2019. For data analysis, the following methods were used: Index methods, Gini coefficient, Lorenz curve, and Grade Data Analysis. The development of the renewable energy sector and modernisation of the energy structure are of great importance for countries to meet their climate obligations. Large-scale energy production from renewable sources could reduce a 60% reduction in the temperature rise. Additionally, such activities will contribute to an increase in energy efficiency by 90%. The energy transition would also bring more comprehensive social and environmental benefits. Thus far, researchers have dealt with energy consumption-related problems in Central and Eastern Europe countries. This article focuses on the production of renewable energy in countries of Central and Eastern Europe. The article fills the research gap in this area. It refers to the situation in the countries of Central and Eastern Europe at a time when developing renewable energy has become very important. In our analysis, we examine renewable energy production in countries located in one region but are and are not EU members. Thanks to this, it will be possible to observe differences in terms of belonging to economic groups. In the case of the pace of changes and the structure of renewable energy produced, a difference can be found between the EU member countries of Central and Eastern Europe and the group of countries outside the EU. The fastest renewable energy production growth was achieved in EU member countries of Central and Eastern Europe. In the case of the mentioned countries, the production of solar, wind, and bioenergy was developed. In other countries, hydropower production was set and treated as a traditional energy source. Generally, in countries of Central and Eastern Europe, the development of energy based on renewable energy sources was not dependent on the pace of economic development of the country. Decision-makers in the countries of Central and Eastern Europe should develop the production of renewable energy from sources that are the easiest and cheapest to use. This is the only way to increase the production of renewable energy in developing countries.

Static properties of leaves with parallel venation, with particular emphasis on the genus EpipactisZinn, 1757 (Orchidaceae, Neottieae) have been modelled with coupled quasi-parallel elastic “beams.” The non-linear theory of strongly bended beams have been employed. The resulting boundary-value problem has been solved numerically with the help of the finite-difference method. Possible dislocations resulting in additional Dirac-delta like forces have been take into account. Morphological similarity of the model and real leaves has been obtained. In particular, the concentrated forces have been shown to cause undulation in the leaves.

The main purpose of this paper is to present the differences in the volume of energy consumption in transport in the EU (European Union) countries. The specific objectives aim to determine the directions of changes and the degree of concentration in the volume of energy utilized by the transport sector in EU states, showing various models in this area, to establish the association between energy absorption and the parameters of the economy and in the field of transport. All EU countries were selected for research by the use of the purposeful selection method as of 31 December 2018. The analyzed period covered the years 2004–2018. For the examination of data, grading data analysis was used as one of the methods of multivariate data analysis. Descriptive, tabular and graphic methods were used to present the results. Findings reveal that there is a general tendency to reduce total energy consumption in the EU countries. The same is the case of energy in transport. Only in 2016–2018 was there an increase in energy absorption in transport. The reason was the better economic situation in this period. Road conveyance is the most important factor in energy utilization (over 90%). The share of other modes of transport was very small. Economically developing countries were the fastest in increasing energy absorption in transport per capita. In turn, highly developed states recorded slight growth and were stable in this aspect. There was a close relationship between energy utilization in transport per capita and GDP per capita. The reduction of energy consumption in transport depends on changes in road haulage, e.g., the pace of introducing innovative energy-saving technologies in automotive transport.

In this study Pickover biomorphs are analysed as being dependent on the chosen complex number system in which iterations of analytic functions are performed. Moran's spatial autocorrelation function and two forms of entropy, Shannon's and the sample entropy, are chosen in order to find correlations and measure complexity in Pickover biomorphs. These turn out to be strongly correlated and low-entropy objects with a fractal dimension between 1.4 and 2. It is shown that there is a strong maximum in correlation and a strong minimum in entropy for the case of Galilean complex numbers corresponding to the square of the generalised imaginary unit being equal to zero.