This work aimed to evaluate the effects of using three different substrates in the semi-hydroponic culture of lettuce (Lactuca sativa L.) using two different nutrient solutions. A first trial was performed with a nutrient solution rich in macronutrients and micronutrients suitable for lettuce culture, and a second trial with a nutrient solution with pretreated wastewater from effluents of a cheese factory. The experimental design was in randomized blocks with three repetitions and three substrates were used: perlite, coconut fiber, and expanded clay, in both trials. The following parameters were observed: number of leaves, diameter of the cabbage, fresh and dry weight of the aerial part, chlorophyll index and mineral composition of the lettuce. For the first trial, the highest result for the number of leaves (20 leaves), fresh weight (142.0 g) and dry weight (7.2 g) of the aerial part was obtained in the plants growing on perlite. In the second trial, the highest result for the number of leaves (28 leaves), diameter of cabbage (26.7 cm), fresh weight (118.8 g) and dry weight (9.5 g) of the aerial part were achieved by the plants that were grown in coconut fiber. The nutrient solutions were analyzed after each irrigation cycle to verify the possibility of their discharge into the environment. Several parameters were analyzed: pH, conductivity, redox potential, nitrates, nitrites, ammoniacal nitrogen, chlorides, hardness, calcium, phosphates, sodium, potassium, chemical oxygen demand (COD) and magnesium. Ammoniacal nitrogen was found to be the only nutrient that can limits the discharge of nutrient solutions into the environment. It was also proven that the plants, besides obtaining the nutrients necessary for their development in the semi-hydroponic system with the nutrient solution with pre-treated residual water, also functioned as a purification system, allowing the said nutrient solution to be discharged into the environment at the end of each cycle.

African countries have shown interest in developing the legal framework for electronic payment as part of digital law. The article aims to analyze the role of the legal framework for electronic payment in the field of digital economy. It relies on a legal methodology through analyzing legal texts related to electronic payment. It also relies on the comparative and descriptive approaches whenever there is a scientific necessity. The article concluded that the legal framework plays an important role in the field of digital economy. This framework appears in the general rules of civil and commercial laws or through the laws of money and credit. Other laws also play a complementary role, such as criminal law and personal data protection laws.

The global significance of the energy crisis and the need for a sustainable European electricity system have intensified interest in renewable energy sources. This study aims to explore the attitudes toward solar energy systems among the population of the North Transdanubian region, which is crucial for companies in the region specializing in solar system installation. The research sheds light on trends in energy prices, potential strategies for addressing the energy crisis, and the regulatory environment for solar systems in Hungary and Austria, focusing on the Burgenland region. The study is divided into two main sections: secondary and primary research. The secondary research presents various applications of renewable energy sources, especially solar energy, and examines energy pricing trends in the two countries, with particular emphasis on the payback period and the impact of changes in energy prices. The primary research is also divided into two parts: the first examines the satisfaction of customers who already use solar systems, and the second focuses on the attitudes of potential customers toward solar investments. The findings provide a comprehensive view of both current users’ and prospective investors’ perspectives on solar energy systems. The practical significance of this research lies in identifying development opportunities for companies, advancing energy efficiency goals, and supporting sustainability efforts.