Discontinuous Bifurcations under 2-DOF Vibroimpact System Moving

Dynamic behaviour of strongly nonlinear non-smooth discontinuous vibroimpact system isstudied. Under variation of system parameters we find the disconti nuousbi furcati onsthat are the dangerousones. It is phenomenon unique to non-smooth systems with discontinuous right-hand side. We investigate the 2-DOF vibroimpact system by numerical parameter continuation method in conjunction with shooting and Newton-Raphson methods, Wife simulate the impact by nonlinear contact interactive force according to Hertz's contact law. We find the discontinuous bifurcations by Floquet multipliers values. At such points set-valued Floquet multipliers cross the unit circle by jump that istheir moduli becoming more than unit by jump. Wealso learn the bifurcation picture change when the impact between system bodi es became the soft one due the change of system parameters, This paper is the continuation of the previous works

Spin-to-Orbital Angular Momentum Conversion in Semiconductor Microcavities

We experimentally demonstrate a technique for the generation of optical beams carrying orbital angular momentum using a planar semiconductor microcavity. Despite being isotropic systems, the transverse electric - transverse magnetic (TE-TM) polarization splitting featured by semiconductor microcavities allows for the conversion of the circular polarization of an incoming laser beam into the orbital angular momentum of the transmitted light field. The process implies the formation of topological entities, a pair of optical half-vortices, in the intracavity field

Problems and methods of improving the quality of jaw crushers

Practically in all metallurgical treatment the raw product needs to be crushed by crushing machines. The main indicator of the crushers quality, which characterize their technical level and competitiveness, is their reliability and durability in the operating conditions, which can be quantitatively assessed by the number of failures in the process of obtaining the finished product on the machine. Among numerous technical reasons for the relatively short, but rather frequent downtimes in the operating conditions of jaw crushers, a significant place is occupied by the downtimes associated with the replacement of the plain bearing liners due to their wear. The rapid wear of liners is the result of not only contact friction between the axle trunnions and liners, but also the action of dynamic forces. The dynamic forces arising from the operation of jaw crushers are due to the presence of a gap in the kinematic pair of link junctions and velocities discrete values of the relative displacement of the links inside the gaps of the friction bearing. Consequently, the reliable operation of the machine largely depends on the creation of conditions that ensure the backlash-free contact of the mating links. It was experimentally proven that the use of mechanisms for taking up the wear of bearings with elastic elements that during the entire cycle of operation of the crank-beam mechanism taking up the wear in the kinematic pairs mating, prevents the appearance of additional dynamic loads and, thereby, increases the reliability of jaw crushers. Thus, the quality of the machine increases, as well as its productivity. © Published under licence by IOP Publishing Ltd

Formation of metallic magnetic clusters in a Kondo-lattice metal: Evidence from an optical study

Magnetic materials are usually divided into two classes: those with localised magnetic moments, and those with itinerant charge carriers. We present a comprehensive experimental (spectroscopic ellipsomerty) and theoretical study to demonstrate that these two types of magnetism do not only coexist but complement each other in the Kondo-lattice metal, Tb2PdSi3. In this material the itinerant charge carriers interact with large localised magnetic moments of Tb(4f) states, forming complex magnetic lattices at low temperatures, which we associate with self-organisation of magnetic clusters. The formation of magnetic clusters results in low-energy optical spectral weight shifts, which correspond to opening of the pseudogap in the conduction band of the itinerant charge carriers and development of the low- and high-spin intersite electronic transitions. This phenomenon, driven by self-trapping of electrons by magnetic fluctuations, could be common in correlated metals, including besides Kondo-lattice metals, Fe-based and cuprate superconductors.Comment: 30 pages, 6 Figure

Features of Nickel-Cadmium Batteries Recycling

The issue of operated-off alkaline nickel-cadmium batteries recycling is currently relevant due to a number of aspects: economic, environmental and social. It is most acute across the national corporation JSC Russian Railways. The article deals with some technological features of operated-off alkaline nickel-cadmium batteries recycling with valuable components being extracted (from the example of nickel-cadmium storage batteries of JSC ”RZD” rolling equipment). The results of leaching in Trilon B synthetic oxides solution, the presence of which is possible in the raw material being processed, are presented in the study. Based on the study of leaching processes of CdO, NiO, FeO, Femet and Fe2O3 in Trilon B solution, the dependence of complexing on the pH of the solution was revealed. The experimental site of the hydrometallurgical processing of the research center (OCGP IC) in the GMO KhMC PJSC ”Uralelectromed” was selected as the testing one for the technology proposed. As a raw material for the tests, a lot of negative lamellae packed in alkaline storage batteries of two different types were used. They were obtained as a result of preliminary drying and cutting at OOO Kursk factory ”Accumulator”. The particle size is 90% - 0.1 mm. The results obtained during the research allowed the author to formulate a hypothesis about the practical use of Trilon B for the processing of operated-off alkaline nickel-cadmium batteries with the extraction of valuable components having greater economic, environmental and social benefits compared to methods based on pyro metallurgy. Keywords: nickel-cadmium batteries, recycling, Trilon B, Russian Railways, hydrometallurgica

Creation, doubling, and splitting, of vortices in intracavity second harmonic generation

We demonstrate generation and frequency doubling of unit charge vortices in a linear astigmatic resonator. Topological instability of the double charge harmonic vortices leads to well separated vortex cores that are shown to rotate, and become anisotropic, as the resonator is tuned across resonance

Analysis of the drawing mill drive operation

For enterprises of the metallurgical industry, the task of increasing the operational life of drawing mills is urgent. The reasons for a significant decrease in the resource and an increase in the number of equipment downtime are related to the operational problems. Downtime due to emergency equipment failures account for up to 45 % of the mill's operating time per month. The paper considers the drive scheme of the drawing mill and analyzes the loss of time to restore its working condition. It is shown that the replacement of a cylindrical gearbox with a gearshift mechanism and a bevel gear with a planetary gear motor equipped with a frequency converter will increase the productivity of the drawing mill by reducing emergency equipment downtime. © 2022 National University of Science and Technology MISIS. All rights reserved

Smartphone-Oriented Development of Video Data Based Services

The massive introduction of video capturing devices in Internet of Things (IoT) environments leads to development of various video data based services. In this paper, we consider the need and background on the video data based services in IoT environments. Based on the smart spaces approach, we introduce the architecture and distributed configurations to construct such services using primarily local devices and to deliver such services using smartphones. We discuss possible data models that can be used on such mediatory components as a local video server and a semantic information broker

Optical vortices with starlight: Implications for ground-based stellar coronagraphy

Using an l = 1 blazed fork-hologram at the focal plane of the Asiago 122 cm telescope, we obtained optical vortices from the stellar system Rasalgethi (alpha Herculis) and from the single star Arcturus (alpha Bootis). We have analyzed the structure of the optical vortices obtained from non-monochromatic starlight under very poor seeing conditions using a fast CCD camera to obtain speckle patterns and carry out the lucky imaging technique, alternative to adaptive optics. With the insertion of a red filter and of a Lyot stop we performed l = 1 optical vortex coronography the double star HD74010. The results are in agreement with theory and numerical simulations. Our results open the way to applications of optical vortices to ground based astronomical observations, in particular for coronagraphy with l > 1 masks. No intrinsic orbital angular momentum was detected in the starlight.Comment: 4 pages, 5 figures. Revised data analysi

Investigation of the Jaw Crusher Operation with Backlash Eliminators

The condition for the appearance of additional dynamic forces in the presence of gaps in the journal bearings of the jaw crusher is determined. The design of the backlash eliminator equipped with pneumatics is described. It was experimentally established that the use of pneumatic devices for backlash elimination in the interfaces of the moving links, using journal bearings, during the operation of the jaw crusher, reduce the magnitude of accelerations and, therefore, increase the reliability of the crusher as a whole. © Published under licence by IOP Publishing Ltd