Double-Versus Triple-Potential Well Energy Harvesters: Dynamics and Power Output.

The basic types of multi-stable energy harvesters are bistable energy harvesting systems (BEH) and tristable energy harvesting systems (TEH). The present investigations focus on the analysis of BEH and TEH systems, where the corresponding depth of the potential well and the width of their characteristics are the same. The efficiency of energy harvesting for TEH and BEH systems assuming similar potential parameters is provided. Providing such parameters allows for reliable formulation of conclusions about the efficiency in both types of systems. These energy harvesting systems are based on permanent magnets and a cantilever beam designed to obtain energy from vibrations. Starting from the bond graphs, we derived the nonlinear equations of motion. Then, we followed the bifurcations along the increasing frequency for both configurations. To identify the character of particular solutions, we estimated their corresponding phase portraits, Poincare sections, and Lyapunov exponents. The selected solutions are associated with their voltage output. The results in this numerical study clearly show that the bistable potential is more efficient for energy harvesting provided the corresponding excitation amplitude is large enough. However, the tristable potential could work better in the limits of low-level and low-frequency excitations.

Energy Harvesting System Whose Potential Is Mapped with the Modified Fibonacci Function.

In this paper, we compare three energy harvesting systems in which we introduce additional bumpers whose mathematical model is mapped with a non-linear characteristic based on the hyperbolic sine Fibonacci function. For the analysis, we construct non-linear two-well, three-well and four-well systems with a cantilever beam and permanent magnets. In order to compare the effectiveness of the systems, we assume comparable distances between local minima of external wells and the maximum heights of potential barriers. Based on the derived dimensionless models of the systems, we perform simulations of non-linear dynamics in a wide spectrum of frequencies to search for chaotic and periodic motion zones of the systems. We present the issue of the occurrence of transient chaos in the analyzed systems. In the second part of this work, we determine and compare the effectiveness of the tested structures depending on the characteristics of the bumpers and an external excitation whose dynamics are described by the harmonic function, and find the best solutions from the point view of energy harvesting. The most effective impact of the use of bumpers can be observed when dealing with systems described by potential with deep external wells. In addition, the use of the Fibonacci hyperbolic sine is a simple and effective numerical tool for mapping non-linear properties of such motion limiters in energy harvesting systems.

Food allergies in rural areas.

INTRODUCTION: A food allergy is a group of symptoms occurring in the organism and resulting from consuming some food, where the problems are conditioned by immunological mechanisms. The symptoms may become apparent first in adulthood and they may be an initial manifestation of a latent allergy. Typical symptoms of a food allergy occur in different organs, thus not only in the digestive system, but also in the skin, respiratory system and circulatory system. AIM: To assess the frequency of food allergy onset in rural areas of the Lublin region as well as to determine which factors induce such allergies. MATERIAL AND METHODS: A survey was conducted, involving the participation of 340 inhabitants of rural areas. The study monitored the knowledge and situation of the disease, concerning allergens, allergy symptoms, methods of treatment and opinions regarding such treatment. RESULTS: The analysis focused on 124 people with diagnosed allergies. CONCLUSIONS: Introducing a diet did not result in a statistically significant difference regarding elimination of the symptoms, as compared to the patients who did not follow any diet. On the other hand, pharmacological treatment causes statistically worse results than using other methods or not being treated at all. The patients in whom allergy symptoms disappeared were more convinced about the positive character of their diet than those in whom the symptoms were not eliminated. The age when the allergy becomes evident does not affect its duration, yet it matters as to the time of its later elimination. The more symptoms were experienced by a patient, the longer the duration of the allergy was.

Analysis of Consumer Behaviour in the Context of the Place of Purchasing Food Products with Particular Emphasis on Local Products.

BACKGROUND: Researchers and marketing specialists study consumer behaviour in the market because it is an important part of economics. There is a growing trend among consumers to buy local products. Consumers know that buying local products is seen to support local producers and entrepreneurs and protect the domestic economy. METHODS: A diagnostic survey analysis was conducted among 404 respondents from Eastern Poland in 2022 to achieve the research objectives. The aim was to present the specifics of the phenomenon of consumer behaviour in relation to the place of purchase of food products, with particular emphasis on local products, according to the qualitative approach adopted. An attempt was made to identify and evaluate the attitudes and declarations of individual consumers in this area. A questionnaire was used as the research tool, and its distribution was carried out entirely electronically via the Internet. RESULTS: The study showed that shopping habits vary by location and age, with hypermarkets and local stores popular among both men and women, while online shopping and wholesale options were also common. CONCLUSIONS: Understanding how consumers make decisions is a complex task, as it involves various factors such as thoughts, emotions and actions that lead to product selection and purchase. These factors can vary based on demographic characteristics, such as gender, age, and location. Studies have shown that Polish consumers are more likely to buy local products from large chain stores than from smaller manufacturer-owned stores, and prefer domestically produced goods, which is reflected in an ethnocentric attitude toward the local market.

Preference-Based Determinants of Consumer Choice on the Polish Organic Food Market.

Background: The development of the organic food market in Poland is currently at a fairly high level. There is a growing demand for organic food, but the share of total sales remains low. There are still many barriers related to the availability of organic food and information about it. In addition, consumers are skeptical of the inspection system in organic farming and admit that these foods do not meet their expectations regarding sensory qualities. Methods: The article conducted its own research, using an author's survey questionnaire, which was distributed in Lublin Province. The research sample consisted of 342 respondents and was diverse in terms of gender, age and place of residence. The purpose of the analysis was to ascertain the determinants affecting the choice of organic food. For the study, the method of correspondence analysis was used, the purpose of which was to isolate characteristic groups of consumers who exhibit certain behaviors towards organic products. Results: Respondents admitted that they buy organic food several times a month, most often spending an amount of EUR 10-20 (per month). They also paid attention to product labeling, with labels read mostly by residents of small towns (up to 30,000 residents). Respondents were also asked about the reasons why they do not buy organic food. The results of the analysis show that respondents believe it is too expensive, but they also cannot point out differences with other products. Conclusions: The main purpose of this article was to study the preferences of organic food buyers and to identify factors that determine their choice but that may also be barriers to purchasing this category of food. These issues need to be further explored so as to create recommendations in this regard for various participants in the organic food market.

The Impact of the Available Infrastructure on the Electric Vehicle Market in Poland and in EU Countries.

The dynamic development of the automotive market entails the need to understand its characteristics. The purpose of this publication is to indicate the changes in the automotive sector resulting from the approaching electromobility. In order to achieve this goal, the market of electric and conventional vehicles in Poland are discussed. This paper discusses issues related to employment in the automotive industry, analyses the location of factories of the largest vehicle manufacturers and analyzes the structure of sales. The development of electromobility in Poland against the background of other EU countries was analyzed in detail. The analysis was based on data from September 2022. The analysis has been conducted by means of computations of the correlation of individual variables (numbers of different types of vehicles: traditional vehicles, BEV and PHEV). The presented results show that the number of BEVs and PHEVs is increasing, and the infra-structure is developing. The number of PHEV cars is usually higher than BEV ones. The results of the analysis of the vehicle market in Poland show occurrence of the variety of vehicle types and variety of the types of vehicle power supplies with alternating current (AC) or direct current (DC). It can be concluded that standardization would be helpful for further development. The number of charging stations is small compared to the number of vehicles, and the advantage of AC stations is evident. This means investing in infrastructure is necessary to enable further development.

Novel Microwave-Assisted Method of Y2Ti2O7 Powder Synthesis.

In the paper, a novel technique for highly dispersed pyrochlore Y2Ti2O7 is proposed. The experimental results proved that the application of microwave irradiation at a certain stage of calcination allowed synthesizing of Y2Ti2O7 in much shorter time, which ensured substantial energy savings. An increase up to 98 wt.% in the content of the preferred phase with a pyrochlore-type structure Y2Ti2O7 was obtained after 25 h of yttrium and titanium oxides calcination at a relatively low temperature of 1150 °C, while the microwave-supported process took only 9 h and provided 99 wt.% of pyrochlore. The proposed technology is suitable for industrial applications, enabling the fabrication of large industrial amounts of pyrochlore without solvent chemistry and high-energy mills. It reduced the cost of both equipment and energy and made the process more environmentally friendly. The particle size and morphology did not change significantly; therefore, the microwave-assisted method can fully replace the traditional one.