INNOVATIVE THREAD METHOD THROUGH CYLINDRICAL HOLES

Innovative activity in the field of engineering and technology, based on the use of best practices, contributes to scientific and technological progress in production. The latest projects in the field of technology significantly increase the technical and economic performance of enterprises. Innovative technical solutions of production nature significantly improve the structure and quality of production. Given the level of the proposed technological changes in the manufacture of threads in through holes, these innovations cover the field of combinatorial and partial. Today mechanical engineering is characterized by mechanization and automation of technological processes, a wide range of products of various parts. Among the non-detachable and detachable joints of parts, the threaded connection is the most common. Simplicity, reliability, the ability to adjust the force with which the conjugate surfaces come into contact, the possibility of repeated cycles of disassembly and assembly, etc., make this type of connection the most commonly used in mechanisms and machines of modern engineering. With the simplicity of the contact pair of threaded joints, where one of them contains the outer and the other the inner screw surface, during their manufacture there are problems that significantly inhibit production. The subject of research of this article is the solution of difficulties of manufacturing of an internal cut in through openings of small diameter by means of a tap. According to various sources, up to 80% of marriage is due to breaking taps. Studies by a group of scientists has found that more than 75% of taps break when the reverse (reverse) stroke of the tap, when the torque reaches its maximum value. The reverse scheme of production of a screw profile of a cutting surface by means of the mechanized devices and their alternative analogs, and also machines of drilling group, is offered.

FLOW CHECK AND ADIABATIC EFFECTIVENESS MEASUREMENTS ON TRADITIONALLY VERSUS ADDITIVELY MANUFACTURED FILM-COOLING HOLES

In the recent years Additive Manufacturing (AM) methods are getting more and more attractive and feasible for the realization of components and subcomponents of gas turbines. They are receiving much attention since, on one hand, the manufacturing of complex 3D geometries is allowed and, on the other, manufacturing and delivery times can be cut down. At the current state of the art, to the authors' knowledge only few applications have yet been commercialized relatively to cooling holes, due to the intrinsic difficulties associated with such a critical feature. Lately, Baker Hughes is studying the possibility to manufacture film-cooling holes via the DMLM technology in order to exploit the flexibility of such innovative manufacturing method and hence eliminate additional processes and lead time. From the open literature it is known that additively manufactured holes can have a more irregular shape and higher roughness than traditional ones, which may lead not only to a reduction in coolant flow but more importantly to a decay of the film-cooling adiabatic effectiveness. For this reason, a test campaign has been conducted in collaboration with the University of Florence (Italy) with the objective of characterizing the performance (minimum passage diameter, flow check and adiabatic effectiveness) of AM vs traditional cylindrical holes on simple-geometry coupons built upon different construction angles. Results were then analyzed in order to fully compare the performance of AM vs traditional film-cooling holes at different operating regimes.

Effect of multi-zone effusion cooling on an adiabatic flat plate for gas turbine application

The present study performed a three-dimensional numerical analysis on an adiabatic flat plate with forward injection holes for multi-zone film cooling. The cooling holes were divided into three-zone, and the cold air was supplied from cylindrical holes at a velocity ratio of 0.5 and 1.5 with 30° inclination to the primary flow. The effect of multi-zone arrangement in film cooling effectiveness is studied, and a comparison between two-zone and three-zone arrangement has been made. Results show that the three-zone arrangement helps achieve better film cooling effectiveness than the two-zone arrangement due to the uniform flow of coolant at a higher velocity ratio. It also reduces the mass flow rate of secondary flow by decreasing the number of cylindrical holes in the perforated plate.

Metaproteomic Comparison of Cryoconite Communities from Caucasian and Novaya Zemlya Glaciers

Anthropogenic pollution strongly affects glacial microbiological communities and promotes glacial melting. In the early stages of glacial melting formation of small cylindrical holes (cryoconite) occurs. While the microbiome of cryoconite is well described, the effect of anthropogenic pollution on cryoconite microbiological communities still has not been fully understood. Thus, we performed an unbiased functional comparison of the cryoconite communities from the highly polluted Caucasian glaciers and from less polluted glaciers in Novaya Zemlya. For this purpose, we used the shotgun metaproteomics approach which has not been used for cryoconite microbiome analysis previously. We identified 475 protein groups, a third of which were found in both glaciers. Cryoconites in both glaciers have similar microbiological communities with Cyanobacteria as dominant phyla. Nevertheless, we found a slight shift from the dominance of phototrophic Cyanobacteria in Novaya Zemlya to heterotrophic bacteria in the Caucasus. We assume that it might be caused by anthropogenic pollution, but other factors such as differences in seasonal dynamics of microbiological communities should be tested in the future.

Selection of parameters during shredding of corn stalks as an additive to the polymer

This paper presents the results of research on the process of grinding dried corn stalks to use them as polylactide filler. Shredding was carried out on a laboratory shredder with the use of a design variant based on discs with cylindrical holes. By selecting the design variant, the appropriate grinding speed and the material pressure on the shredder discs, the most favourable parameters in terms of the quality of the shredded product and low energy consumption were selected. The research was conducted to reduce the energy demand during the shredding process and to obtain the shredded material suitable for further processing steps.

Spherical micro-hole grid for high-resolution retarding field analyzer

A wide-acceptance-angle spherical grid composed of numerous micro cylindrical holes was developed to be used for the retarding grid of a display-type retarding field analyzer (RFA) and to enhance the energy resolution (E/ΔE). Each cylindrical hole with a diameter of 50 µm and a depth of 80 µm is directed to the spherical center. The inner radius of the spherical grid is 40 mm. The holed area corresponds to an acceptance angle of ±52°. The E/ΔE of an RFA equipped with the developed holed grid was estimated to be 2000 from a measured Au 4f photoemission spectrum. A clear photoelectron hologram was observed in the Mo 4p core-level region of MoS2, indicating that the RFA with the holed grid is effective for photoelectron holography.