Research of Radial Forces and Torque of Bearingless Synchronous Machine

Bearingless synchronous machine (BSM) is an electrical machine which rotor is suspended by electromagnetic forces (not ball bearings). It allows achieving ultra-high rotation speed and significantly extending area of electric drive application. Nowadays there are different variants of the machines with the structural design and the searching  of optimal solution is going on. The basic calculation parameters of bearingless machines are radial forces that can withstand the rotor from external load and torque produced on the shaft. This article describes the theoretical results based on a computer model that produces the finite element method and experimental study of the BSM prototype

ADAPTIVE CONTROL OF THE 1-DOF ACTIVE MAGNETIC BEARING

Active magnetic bearing is the electromechanical device allowing to suspend the rotor of the electric machine. Friction is eliminated and high speed of rotation can be achieved. However, the parameters of the electromechanical system may change during operation. Adaptive control system allows to maintain stability under varying parameters

Gold Allocation Forms in Sulfide Ore and Products of their Processing Enrichment

Gold in sulfide ores and technogenic formations after their processing is concentrated in the form of micro-dispersed particles. This article presents a study on the composition of the ultrafine gold particles, their size distribution, and some predicted gold properties. The studies were carried out using copper pyrite ore as an example. It was found that the content of metallic impurities in Au particles, which may appear during their formation under natural conditions, increases with a decrease in their size. The presence of copper in gold particles significantly lowers the melting point of the alloy. The data obtained are used to develop a technology for utilizing gold from technogenic formations of a similar type. Keywords: gold particles, copper, metallic impurities, alloy, radius of particl

INDUCTIVE LINEAR DISPLACEMENT SENSOR IN ACTIVE MAGNETIC BEARING

Active magnetic bearings are increasingly used in various fields of industry. The absence of mechanical contact makes it possible to use them in ultra-high-speed electric drives. The main trend of active magnetic bearings development is the improvement of the control system. The main problem of the control system is the displacement sensor (most of them has low accuracy and large interference). The sensor must have the following properties: simple in realization, high linearity of the characteristic, high sensitivity and noise immunity, high reliability. At the present time there is no sensor that satisfies all these conditions. Most manufacturers use various kinds of filters to get an accurate position signal. This increases the response time of the control system. Thus, problem of designing and modeling the position sensor, considered in the article is topical

Beyond Charge Transfer: The impact of auger recombination and FRET on PL quenching in an rGO-QDs system

PL intensity quenching and the PL lifetime reduction of fluorophores located close to gra‐ phene derivatives are generally explained by charge and energy transfer processes. Analyzing the PL from PbS QDs in rGO/QD systems, we observed a substantial reduction in average PL lifetimes with an increase in rGO content that cannot be interpreted solely by these two processes. To explain the PL lifetime dependence on the rGO/QD component ratio, we propose a model based on the Auger recombination of excitations involving excess holes left in the QDs after the charge transfer process. To validate the model, we conducted additional experiments involving the external engi‐ neering of free charge carriers, which confirmed the role of excess holes as the main QD PL quench‐ ing source. A mathematical simulation of the model demonstrated that the energy transfer between neighboring QDs must also be considered to explain the experimental data carefully. Together, Au‐ ger recombination and energy transfer simulation offers us an excellent fit for the average PL life‐ time dependence on the component ratio of the rGO/QD system

Traditional Arctic native fish storage methods and their role in the sustainable development of the Arctic

The business of the Arctic has received increased attention owing to climate change. However, resource development and the use of waterways threaten the fragile Arctic ecology. The indigenous people of the Arctic have acquired a vast amount of traditional knowledge about coexisting in harmony with nature over the course of many years. Herein, five types of fish storage facilities that are commonly used by Arctic indigenous people and their working mechanisms are described. The traditional knowledge of the Arctic indigenous people is practically applied in Arctic fish storage systems, which are still common, effective, and environmentally friendly. The traditional fish storage facilities of the aborigines are of significance because they promote the sustainable development of the Arctic