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Numerical Study of the Natural Oscillations of Perforated Vibrating Surfaces with Holes of Complex Geometry

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Kharchenko S. , Samborski S. , Kharchenko F. , Paśnik J.

tom Vol. 17, no 6

73--87

The widespread use of perforated vibrating surfaces in various industries requires maximum productivity and construction reliability. The research task is to determine the significant factors and their degree of influence on the natural oscillations of vibrating surfaces with multiple holes of complex geometry. For this purpose, studies were carried out for three samples of plates: non-perforated, with basic round holes and holes of complex geometry in the form of a five-petal epicycloid. Studies of the natural oscillations of perforated vibrating surfaces have been conducted using the finite element method in Abaqus, which has proved sufficient accuracy of calculations. The dependencies of the natural oscillation frequency of perforated surface samples on their thickness, partition width between the holes, material type, and fixing method have been obtained. In addition, the analysis involved the study of eight modes of oscillation common in practice. The dependencies of the natural oscillation frequency of perforated surface on the relative parameters of ligament efficiency and stiffness coefficient have also been obtained. These parameters take into account the ratios of the partition width between the holes to the plate thickness and the dimensions of the holes. The research results allow to obtain levels of influence of the perforated vibrating surface parameters on their natural oscillations frequency. The obtained research results make it possible to further determine the absence of damage between the holes and predict the durability of perforated vibration surfaces in the presence of holes of complex geometry.

Dynamics of Productivity of Leguminous Plant Groups during Long-Term Use on Different Nutritional Backgrounds

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Karbivska U. , Butenko A. , Kozak M. , Filon V. , Bahorka M. , Yurchenko N. , Pshychenko O. , Kyrylchuk K. , Kharchenko S. , Kovalenko I.

tom Vol. 24, nr 6

190--196

Deterioration of ecological situation, increase of mineral fertilizer prices and their foreseen increase in recent years force us to look for the ways to reduce the rates of their application and alternative means of maintaining high productivity of sown fodder lands. Fertilization was and remains one of the decisive ways of increasing haymaking productivity, as well as increasing their economic efficiency. The productivity of leguminous grasses based on the study of agrotechnological measures of cultivation in the conditions of the Carpathian region is currently relevant. The studied species of perennial grasses, during the three-year cultivation, showed that the largest number of shoots was formed on the variant with horned sedge and was 1185–1201 pieces/m2. Medicago sativa had the smallest number of shoots (470 pics/m2, control (without fertilizers)). Trifolium pratense and Lotus corniculatus provided the highest productivity in relation to other species from 20 to 31%. Analysis of single–species crops productivity of perennial bean grasses by cuttings showed that the peculiarities obtained on average for all slopes, were also similar in each of two slopes. During the three–year use of the herbage on the yield from 1 ha of dry mass in both slopes, the herbage factor had the greatest influence, the share of which was 61–62%, while the share of the influence of fertilizer was 38–39%.

The Influence of Elements of Technology and Soil-Climatic Factors on the Agrobiological Properties of Onobrychis Viciifolia

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Kovalenko V. , Tonkha O. , Fedorchuk M. , Butenko A. , Toryanik V. , Davydenko G. , Bordun R. , Kharchenko S. , Polyvanyi A.

tom Vol. 25, iss. 5

179--190

The significance of this study stems from the imperative to justify and advance agrobiological foundations aimed at enhancing the cultivation practices of Onobrychis viciifolia. There exists a compelling necessity to refine agronomic methodologies and streamline their comprehensive efficacy within the technological phases of cultivation. This study is aim to provide a critical analysis of scientific problem of substantiation of biological and organic foundations of the technology of Onobrychis viciifolia growing. Innovative technological interventions were formulated by extrapolating discerned patterns of influence pertaining to climatic and meteorological factors. Patterns governing the growth, development, and productivity formation of Onobrychis viciifolia were identified, and both the theoretical and practical principles of contemporary methods for cultivating perennial legumes were established. The chemical compound of aboveground biomass of Onobrychis viciifolia is varied depending on researched factors. Fertilization practically did not increase the productivity of Onobrychis viciifolia. The natural fertility of low-humus chernozem soil ensures the formation of a high, stable yield without fertilizing. This is the evidence that Onobrychis viciifolia compares favorably with other perennial legumes. Due to its biological characteristics, it is much more effective, especially in leveraging natural factors for the yield formation, i.e., it plays a significant role in the biologization of plant production, and in obtaining the most environmentally friendly, high–quality, yet cheap feed. The outcomes derived from the conducted research indicate that, under uniform soil conditions and varying fertilizer levels, the mowing height emerges as the predominant factor. The highest concentrations of nutrients within the overground biomass of Onobrychis viciifolia were noted at a cutting altitude of 11 centimeters. Concurrently, an elevation in crude protein and ash content was observed, accompanied by a concomitant reduction in the index of crude fiber.