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

Corrosion resistance of alloys of Hastelloy in chloroaluminate melts

The corrosion of Hastelloy S, Hastelloy X, Haynes 230, Hastelloy N, Hastelloy G35 and Hastelloy C2000 alloys was studied in KCl-AlCl3 melts at 550°С. The rates and the mechanisms of corrosion of the studied materials were determined. The processes taking place during the interaction between alloys and chloroaluminate melts were investigated

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

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

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