INFLUENCE OF VANADIUM DOPPING ON DIELECTRIC PROPERTIES OF BARIUM TITANATE CERAMICS

The purpose of this article is to present the impact of vanadium substitution on the dielectric properties of barium titanate. Doping barium titanate (BaTiO3) by different ions such as vanadium V5+ provides the possibility of changing its dielectric properties. SEM images indicate the differences between pure BaTiO3 (BT) and Ba(Ti0.98V0.02)O3 (BTV2). Using dielectric measurements, the Curie temperatures (Tc) were calculated – they were found to be equal to 403 K and 396 K, respectively. Moreover, for BTV2 the Curie - Weiss temperature and the Curie constant (C) were determined (T0 = 368 K and C = 1.46 ×105 K, respectively)

Temperature and E-Poling Evolution of Structural, Vibrational, Dielectric, and Ferroelectric Properties of Ba1−xSrxTiO3 Ceramics (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.45)

Poland’s high-performance computing infrastructure PLGrid (HPC Centers: ACK Cyfronet AGH) for providing computer facilities and support within computational grant no. PLG/2022/015969. Innovative research and scientific platform for a new class of nanocomposites, financed by the Ministry of Education and Science, contract number 7216/IA/SP/2021.Lead-free Ba1−xSrxTiO3 (BST) (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.45) ceramics were successfully prepared via the solid-state reaction route. A pure perovskite crystalline structure was identified for all compositions by X-ray diffraction analysis. The basic phase transition temperatures in these ceramics were studied over a wide temperature range. A change in symmetry from a tetragonal to cubic phase was detected, which was further proven by phonon anomalies in composition/temperature-dependent Raman spectra. The incorporation of Sr2+ into BaTiO3 (BT) lead to a shift in the phase transitions to lower temperatures, suppressing the ferroelectric properties and inducing relaxor-like behavior. Therefore, it was reasonable to suppose that the materials progressively lack long-range ordering. The initial second-harmonic generation (SHG) measurements demonstrated that the cubic phase of BST ceramics is not purely centrosymmetric over a wide temperature interval. We discussed the possible origin of the observed effects, and showed that electric field poling seems to reconstruct the structural ordering destroyed by the introduction of Sr2+ to BT. In the first approximation, substitution of Sr for larger Ba simply reduced the space for the off-central shift in Ti in the lattice and hence the domain polarization. A-site cation ordering in BST and its influence on the density of electronic states were also explored. The effect of doping with strontium ions in the BST compound on the density of electronic states was investigated using ab initio methods. As the calculations showed, doping BT with Sr2+ atoms led to an increase in the bandgap. The proposed calculations will also be used in the subsequent search for materials optimal for applications in photovoltaics. --//-- This is an open access article Suchanicz, J.; Sitko, D.; Stanuch, K.; Świerczek, K.; Jagło, G.; Kruk, A.; Kluczewska-Chmielarz, K.; Konieczny, K.; Czaja, P.; Aleksandrowicz, J.; et al. Temperature and E-Poling Evolution of Structural, Vibrational, Dielectric, and Ferroelectric Properties of Ba1−xSrxTiO3 Ceramics (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.45). Materials 2023, 16, 6316. https://doi.org/10.3390/ma16186316 published under the CC BY 4.0 licence.the Ministry of Education and Science, contract number 7216/IA/SP/2021; The Institute of Solid State Physics, University of Latvia at the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2

PRICE DIFFERENTIATION OF AGRICULTURAL PRODUCTS IN POLAND – REGIONAL APPROACH

The main aim of the research was to assess the price differences of selected agricultural products in the area of the first degree administrative division of Poland. The study focused on the analysis of the dynamics of price changes in individual regions, specified the impact of the production volume and consumption of a given product on the retail price, and an attempt was made to define a regression model in terms of the price of an agricultural product. The years 2010-2019 were assumed as the research period, and four products were analyzed: sugar, eggs, flour and milk. It was found that the average annual dynamics of changes was similar for all voivodeships, in particular for products such as flour, eggs and sugar. In the case of the correlation analysis, it was found that there was a certain interdependence of prices in relation to production and prices for consumption, which is not coherent on a regional basis. The regression model analysis proved ineffective in trying to forecast future market behavior as well as consumer behavior

FOOD CHAIN PRICE DIFFERENCES – THEORETICAL AND METHODOLOGICAL ASPECTS

The article is for illustrative purposes and presents the general situation of price differences in the food chain in theoretical and methodological aspects. The main objective of the research was to assess the market situation of the purchase of agricultural products against a background of prices in retail stores. The research was conducted using the observational method in mid-2021. The subject of the study were the 20 most popular agricultural products, purchased directly from the agricultural producer and through retail chains as products ready for sale unchanged from the moment of purchase. The volatility of prices between different links in the food chain was also determined using Pearson’s linear correlation. The differences in the estimated percentage mark-up of selected retail chains in relation to the obtained values of the price relation index are presented. It was found that the analyzed price differences constituted a complex research problem and were conditioned by many determinants. The relation between the prices offered for agricultural products in purchase and retail prices was often 200%. The main reason for the price differences was the extensive supply chain between the farmer and the chain of stores. The results of the correlation of price volatility allowed to conclude that there was a phenomenon related to the transfer of price risk in the scope of subsequent links of the food chain

Prognozowanie rozwoju energii elektrycznej z odnawialnych źródeł energii w Polsce na tle krajów Unii Europejskiej

One of the key elements in the development of countries is energy stability particularly related to ensuring, among other things, continuity of power supply. The European Commission is trying to protect the security of energy supply by introducing internal conditions regarding the share of RES in everyday life. The aim of this article is to forecast the share of RES in electricity production for all the EU member states. The study covers the years 1985-2021, the research is based on two models: the autoregressive (AR) model and the Holt-Winters model, whereas the prediction values were deter-mined for the period 2022-2030. The prediction values showed that Denmark, as the only one of the community countries, may turn out to be self-sufficient in terms of electricity production from RES already at the turn of 2026-2027. In the case of Poland, there is a high probability that the projected RES share for 2030 will not be met. Potentially, for most EU countries, the energy produced from RES will satisfy at least 50% of electricity demand by 2030. A projection of the chances of meeting the commitments presented in the National Energy and Climate Plans regarding the share of renewable energy sources in electricity production in the EU member states in 2030 indicates that they will not be met in most EU economies.Jednym z kluczowych elementów rozwoju krajów jest stabilność energetyczna szczególnie związana z zapewnieniem ciągłości zasilania, m.in. w energię elektryczną. Komisja Europejska próbuje uchronić bezpieczeństwo dostaw energii wprowadzając wewnętrzne uwarunkowania dotyczące udziału OZE w życiu codziennym. Celem artykułu była prognoza udziału OZE w produkcji energii elektrycznej dla wszystkich krajów członkowskich Unii Europejskiej. Badanie przeprowadzono analizując lata 1985-2021, gdzie badania oparto o dwa modele: autoregresyjny (AR) oraz model Holta-Wintersa, a wartości predykcji zostały wyznaczone dla okresu 2022-2030. Wartości prognoz wykazały, że Dania jako jedyny z krajów wspólnoty już na przełomie 2026-2027 może okazać się państwem samowystarczalnym pod względem produkcji energii elektrycznej z OZE. W przypadku Polski istnieje duże prawdopodobieństwo niespełnienia oczekiwań udziału OZE w planowanym udziale na rok 2030. Potencjalnie, dla większości krajów UE energia produkowana z OZE dla 2030 r. będzie zaspokajać przynajmniej 50% zapotrzebowania na energię elektryczną. Prognoza dotycząca szans realizacji przedstawionych w krajowych planach na rzecz energii i klimatu zobowiązań dotyczących udziału odnawialnych źródeł energii w produkcji energii elektrycznej w krajach członkowskich Unii Europejskiej w 2030 roku wskazuje, że nie zostaną one spełnione w większości gospodarek unijnych

OCENA PORÓWNAWCZA PRODUKCJI I CEN MLEKA KROWIEGO W PAŃSTWACH CZŁONKOWSKICH UNII EUROPEJSKIEJ

The paper presents issues related to milk production in the Member States of the European Union. The conducted analysis and research cover the period from 2015 to 2019. The study evaluates milk production and milk prices and uses the linear Pearson’s correlation in order to find out whether there is a correlation between milk prices in the individual European Union Member States. The research demonstrated that the market value of milk produced in Poland increases every year and that there is a strong and very strong correlation between individual milk prices in the Member States amounting to 85% of all surveyed entities.W artykule przedstawiono zagadnienia związane z produkcją mleka w państwach członkowskich Unii Europejskiej. Przeprowadzona analiza oraz badania dotyczą okresu od 2015 do 2019 roku. Dokonano oceny produkcji i cen mleka oraz przeprowadzono badanie korelacji liniowej Pearsona w celu uzyskania odpowiedzi, czy istnieje współzależność cen mleka w poszczególnych krajach Unii Europejskiej. Badania dowiodły, że wartość rynkowa wyprodukowanego mleka w Polsce corocznie wzrasta, oraz że istnieje silna oraz bardzo silna zależność między poszczególnymi cenami mleka w państwach członkowskich, wynosząca 85% wszystkich badanych podmiotów

Comparative Assessment of Cow’s Milk Production and Its Prices in the Member States of the European Union

The paper presents issues related to milk production in the Member States of the European Union. The conducted analysis and research cover the period from 2015 to 2019. The study evaluates milk production and milk prices and uses the linear Pearson’s correlation in order to find out whether there is a correlation between milk prices in the individual European Union Member States. The research demonstrated that the market value of milk produced in Poland increases every year and that there is a strong and very strong correlation between individual milk prices in the Member States amounting to 85% of all surveyed entities