A New Species of the Genus Eurytoma (Hymenoptera, Chalcidoidea, Eurytomidae) from the Galls of Liposthenes glechomae (Hymenoptera, Cynipidae). Zerova, M. D., Klymenko, S. I. -Eurytoma trjapitzini Zerova et Klymenko, sp. n. is described. Th e new species belongs to the pistaciae species group diff ering from all known species by numerous (10-12) long setae on hind tibia (2-3 in the other species) and on hind femur. An improved key to species of the pistaciae group is provided. Th e holotype and paratypes of the new species are deposited in the collection of the I. I. Schmalhausen Institute of Zoology, Kyiv.
The principles of creating hybrid processing processes based on the functional approach are given. It is proposed to consider the formation of individual elements of the product (planes, holes, fillets, ledges) through functions that are provided by a combination of such elements. At the same time, the required depth of technological influences is analyzed, based on which a set of influences that are different in nature, but compatible, on some basic carrier, is selected. It is proposed to use a high-speed liquid flow as such a carrier. Hybridization of a tool based on a water jet of small diameter can be achieved by combining with laser heating, cryogenic cooling, and the formation of a flow of ice particles, mechanical initiation of surface damage with further development of surface defects. The high efficiency of hybrid processes for processing composite materials is shown.
The values of residual stresses in PVD-coatings of titanium, aluminum and niobium nitrides are determined by the flexible specimen method. An experimental-and-calculation procedure for separating the structural and thermal components of residual stresses is proposed that allows one to determine the thermal expansion coefficients of the coating materials and a general level of residual stresses in coatings on a substrate of any material. The dependence of the residual stress on the roughness of the substrate surface is established. The possibility of adjusting the level of residual stresses in coatings by the discrete surface topography formation is shown.Keywords: vacuum plasma coatings, residual stresses, roughness, thermal and structural components of the residual stresses, discrete topography.Introduction. Plasma vacuum deposited (PVD) nitride-based coatings exhibit high hardness and good adhesion to substrates. Owing to their considerable wear-and heat resistance, these are widely used to enhance the performance of cutting and deforming tools, friction pair components, gas turbine engine (GTE) blades. The analysis of the data given in the literature shows that these coatings exhibit considerable residual compressive stresses whose level is from hundreds of megapascals (MPa) to a dozen of gigapascals (GPa) [1-6]. The residual stresses are induced by both the difference in the thermal expansion coefficients of the substrate and coating materials (the thermal component) and the interaction between the growing crystallites (the structural component) [1,7].As argued by the authors of [2,8], the coating stresses due to the structural component (the coating growth stresses) are independent of the substrate material, and the difference between the level of residual stresses in coatings deposited on different substrates is dependent on the thermal component. It is the high level of residual compressive stresses that the crack growth resistance, wear-resistance and corrosion resistance of surfaces modified by vacuum plasma coatings can be related to [9][10][11]. As noted in [12], a high level of residual compressive stresses retards the crack formation processes in coatings during operation of cutting tools, especially under conditions of interrupted cutting. The presence of considerable residual compressive stresses affects positively the characteristics such as fatigue limit [13] and yield strength [14]. At the same time, owing to a high level of residual compressive stresses, the coatings become more brittle, which can result in their spontaneous delamination even prior to the beginning of the operation or to the breakage of adhesion between the substrate and coating during the operation [15][16][17][18][19][20].In this connection, it is necessary to determine the possibilities on the adjustment of the level of the residual compressive stresses in coatings. Attaining this goal is possible by way of improving the coating deposition process and creating the suitable surface architecture. Commonly used methods for adju...
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