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Abstract Thick smoothly graded AlxGa1−xAs layers (50–100 µm) are used in light-emitting diode structures and also for creation of high-power photovoltaic converters with side-input of laser radiation. To achieve the required thickness of the AlxGa1−xAs layer the high temperature LPE growth technique is required. However high epitaxial temperature increases the unintentional doping level. Epitaxy from mixed Ga–Bi melts was investigated as a way to solve this problem. It was found that for growing relatively thick AlxGa1−xAs layers, it is expedient to use Ga–Bi melts with 20 at% or less bismuth content. SIMS and Hall characterization of AlxGa1−xAs layers revealed that the growth of AlxGa1−xAs from mixed Ga-Bi melts reduces the background doping level (including carbon) and influences the native defect formation keeping the n-type conductivity. This effect is explained by the changes of the group III and V elements concentrations in the melt as well as Bi incorporation in the lattice.

The aim of this study was to develop a new manufacturing process for bimetallic materials by combining laser treatment with traditional casting methods. This process involves laser-treating nickel alloy-grade UNS 6230 plates to create a regular macro-relief on their surface. These treated plates are then placed in a sand mold, and molten non-alloy steel (S235JRG2) is poured into the mold to create bimetallic layered castings. The experimental procedure focuses on optimizing the melt-to-solid phase ratios and pouring temperatures to achieve a uniform microstructure and strong mechanical properties in the bimetals. The produced bimetallic castings are suitable for applications in the oil refining and chemical industries and heavy machinery sector. The quantitative results indicate that the optimized process parameters lead to a high-quality transition zone with minimal defects, characterized by the diffusion of alloying elements from the nickel alloy to the steel. The microstructure, chemical, and phase compositions were evaluated using XRD and SEM with EDS, confirming the formation of a robust metallurgical bond. Key findings include a significant improvement in the hardness and strength of the transition layer, with the optimal pouring temperature being 1600 °C. The resulting bimetallic materials demonstrate an improved performance in demanding industrial environments.

The work is devoted to the study of herbs of the representative genus Clover Trifolium fragiferum L. from the south Ukrainian flora. The aim of this research is to investigate the representative of Southern Ukraine flora Trifolium fragiferum L. which has a sufficient raw material base and use in folk medicine. Materials and methods. Samples were grown in the suburbs of Zaporizhzhia and harvested during full flowering (May – June). Microscopic analysis was performed with temporary preparations of leaves and stems. Plant extracts were analyzed chromatographically using an Agilent Technologies 6890 gas chromatograph with mass spectrometric detection. Results. The leaf is covered with parenchymal cells with slightly thickened membranes with anocytic stomata. The main parenchyma is composed of rounded toxoid cells. Stem rounded, covered with elongated parenchymal cells with thin membranes with almost no stomata and pubescence. Central axial cylinder is of beam type. Beams are open collateral, large. Above the phloem of the bundles is a multilayered sclerenchyma. The core is partially filled, hollow in the center. 63 compounds were found in the native extract, of which 37 were identified: coumarins, fatty acids, diterpene alcohols, oxygenated hydrocarbons of terpenoid nature, higher hydrocarbons, representatives of phytosterols, and phytosterols. After acid hydrolysis with sulfuric acid, 58 compounds were found, of which 49 were identified: coumarins, alcohols and phenols, aldehydes and ketones, compounds of diterpene nature. Conclusions. Pharmacognostic analysis of the genus Clover Trifolium fragiferum L. revealed diagnostic microscopic signs of leaves and stems. The components of the native extract are compared, and after its acid hydrolysis. Certain regularities in the distribution of classes of substances that characterized certain types of extracts were revealed: monoterpenoids, aromatic, heterocyclic compounds characterized the hydrolyzed product. Sesquiterpenes and steroid compounds are found only in the native extract of strawberry clover herb. Alcohols, aldehydes, and ketones were the majority in the hydrolyzed extract, and hydrocarbons were observed more in the native. Only 5 components were identified in both extracts: nonacosan, 2-phenoxyethanol, loliolide, dihydroactinidiolide and coumarin with significant differences in amounts.

The development of GaAs based high power side-input photovoltaic converters requires thick (50–100 μm) transparent gradient refraction layers that can be grown by liquid phase epitaxy. Such thick layers can also be used in LED structures. To solve the problem of AlxGa1-xAs conductivity reduction at the x∼40% point a five-component, Al-Ga-As-Sn-Bi system is proposed. The interaction parameters in the liquid phase (αij) in the Al-Ga-As-Sn-Bi system are determined within the framework of a quasi-regular solutions model. For an AlxGa1-xAs solid solution growing from a Ga-melt containing 10 at.% of Bi (as a neutral solvent) and 15 at.% of Sn (as an n-type dopant), liquidus and solidus isotherms for 900 °C are modeled based on the calculated αij. Satisfactory agreement between calculated and experimental data has been obtained. Hall data show that AlGaAs layers grown from Bi-containing melts have n-type conductivity. Doping by tin during growth from mixed Ga–Bi melts makes it possible to increase the electron concentration in the AlGaAs layer.

The world plant products market is expanded rapidly and trade in them tends to grow by 15–25 % annually. The number of reports is increased proportionally about accidental contamination or deliberate, economically motivated falsification of plant raw materials. 27 % of the nearly 6.000 herbal preparations that are sold in 37 countries have contained undeclared contaminants, substitutes, or other components, according to the literature. We have conducted a plant conduction system microscopic analysis of the individual members’ genus Clover (Trifoliae L.), Fabaceae L. to identify morphoanatomical characteristics. Clover has anti-inflammatory, antiseptic, choleretic, diaphoretic, diuretic, hemostatic, expectorant, astringent properties and is used in many diseases. Aim. The finding common features and those that differ and can be used as diagnostic during studying the conducting system structure of genus Trifolium L. leaves and stems. Materials and methods. Plant material (herb) from Trifolium pratense L., T. incarnatum L., T. repens L. and T. fragiferum L. was harvested during the active flowering period – (May – June) and was dried in a well-ventilated place. Leaves and stems preparations were pre-boiled in 5 % sodium hydroxide water solution and fixed in chloral hydrate solution. Cross-sections were made with a microtome. The BIOLAM LOMO light microscope (Russia) and OLYMPUS SH-21 digital camera were used to record the data about identify the conducting apparatus of the plant’s leaf, petiole, and stem. Results. It has been examined the central vein structure of T. pratense L. and T. fragiferum L. leaves, it was determined that the conductive system is covered with a crystalline coating and there is one closed collateral bundle in the center, which is not typical for dicotyledonous plants. The petioles of T. incarnatum L., T. fragiferum L., and T. repens L. in cross-section are several different shapes. There are kidney-shaped and round. The conducting apparatus T. incarnatum L. and T. repens L. have arranged in a circle, closed and collateral. The leafstalk structure type of T. fragiferum L. is bunchles. It contradicts too the information about the structure conducting system of dicotyledonous plants. The stem’s conducting bundles are collateral and open. Conclusions. We have paid attention to the structural peculiarities of the conductive system of the central vein and petiole of objects for study: Trifolium pratense L., T. incarnatum L., T. repens L., and T. fragiferum L. when searching for differentiating features in some members of the genus Trifoliae L. in pharmacognostic analysis. The Dicotyledonae representatives are not characteristic of the closed type of conductive bundles, which we observed during microscopic examination.

One of the main rapidly developing directions of tourism both in the world and in Ukraine in particular is urban tourism. As centuries ago, so nowadays, the cities are the goal of many travels, and the territorial recreational systems based on them are the most developed ones, which is explained by the high concentration of tourism resources in a conventionally limited space. Despite all this, in the sphere of urban tourism in terms of a territorial recreational system there is an uneven provision of recreational demand for communication with nature due to the insufficient number of natural recreational objects. As a solution to the common problem for recreation and urban tourism, it is proposed to implement a number of measures consistently both at the State level and at the level of local authorities or local self-government bodies, namely: to create conditions under which private and communal enterprises would be interested in the creation and development of natural recreational formations in the form of parks, gardens, squares, embankments. The program for the development of natural recreational spaces in cities – i.e., tourism centers – envisages that private and communal enterprises that will create these natural recreational spaces will carry out reconstructions of the already existing formations and will have the opportunity to engage in such natural recreational formations with commercial activities related to the organization of the provision of recreational services. In addition, it is important to strengthen the State supervision over compliance with the State sanitary rules for planning and development of settlements, because, in terms of landscaping, large cities of Ukraine have long failed to meet the requirements. At this, one considers appropriate to involve scientific and educational institutions related to tourism and recreation in the design of these natural recreational formations, which will allow to implement tourism in the city on not only practical, but also on scientific basis. It is believed that in case of materialization of the proposed program, the city will receive additional centers of attraction for tourists, which, in turn, will have positive consequences for the further development of cities as centers of tourism and recreation.

The article seeks to address a fundamental gap in collective moral responsibility research by exploring a collectivist rather than the dominating individualist perspective on the relationship between a private individual and the collective whole. In particular, it presents a qualitative case study of ideas of outstanding Ukrainian teacher, methodologist and theorist of education, founder of the pedagogical school Anton Semenovych Makarenko and his collectivist pedagogy as a major educational paradigm implemented within the context of the Soviet state and society. The analysis of the concepts of collective experience, communist personality, collective, distribution of powers, responsibility, and discipline contributes to a better understanding of the nature of individual and collective moral responsibility. At the same time, the article argues that a consistent implementation of the collectivist worldview results in an essentially flawed misbalanced relationship between an individual and the collective of people. In the Soviet context, such misbalance is evidenced in the phenomena of the cult of personality and state paternalism. As a consequence of identifying responsibility with discipline, the individual personality is deprived of its moral and utilitarian autonomy, devalued, and forcibly assimilated by the collective whole perceived as the highest authoritative source of moral judgement and the sole distributor of moral responsibility. Consistent implementation of the collectivist worldview in the context of Soviet society inevitably leads to an imbalance in the relationship between individual and collective principles and, ultimately, the justification of any coercion and violence by the state as such a team performing the highest guardianship and pedagogical function.

The data on the composition and amount of amino acids have been analyzed in the raw materials of five legume species. All of them grow in Southern Ukrainian flora (Securigera varia (L.) Lassen, Vicia cracca L., Lupinus luteus L., Melilotus officinalis (L.) Pall., Melilotus albus Medic.) and may be used as a source of amino acids, especially essential, whose resource has to be replenished from the outside. Aim. We have studied and compared the amino acid profile of some species of the Ukrainian South Legumes, and used the multidimensional statistical cluster analysis to construction of histograms based on the amino acids content and composition of such plants as: Securigera varia (L.) Lassen, Vicia cracca L., Lupinus luteus L., Melilotus officinalis (L.) Pall., Melilotus albus Medic. Materials and methods. The raw materials were harvested at the South of Ukraine and were investigated by gas-liquid chromatography. The amino acid analyzer has been used after hydrochloric acid hydrolysis at elevated temperature. Results. 19 amino acids have been identified, of which nine are essential or partially interchangeable. The non-polar amino acid proline is in the lead in terms of quantity among the essential amino acids. Its amount was 6932 mg/100 g and the ability to accumulate it was noted in Melilotus officinalis (2276 mg/100 g). The smallest proline amount was found in Lupinus luteus (388 mg/100 g). The sulfur-containing non-polar amino acid methionine is in the smallest amount in the selected plants (506 mg/100 g). Our attention was drawn to the absence of the polar amino acid glutamine among the non-essential amino acids in some plants. Securigera varia, Vicia cracca, and Melilotus officinalis did not contain glutamine. In this subgroup, the polar aspartic acid was found in the highest amount (6824 mg/100 g) with the highest content in Vicia cracca and the lowest – in Melilotus albus (2660 mg/100 g and 385 mg/100 g, respectively). Conclusions. The analysis of the presence and number of amino acids was the basis for our multidimensional statistical cluster analysis and histograms of the presentation of the amino acid profile of the studied plant members of the family Fabaceae L. In constructing the dendrogram, three clusters were identified, and representatives of one genus (Melilotus L.) were attributed to different clusters which is significant for further chemosystematic studies.