Low-temperature induction heating of flat metal objects in a traveling electromagnetic field

The article discusses possible options for a low-temperature induction heating system (LTIHS) of flat metal products in a traveling electromagnetic field. The problem of calculating eddy currents, active and reactive powers induced in a heated flat object, as well as electromagnetic forces acting on the object moving it in a given direction, is posed and solved. A mathematical model has been developed that takes into account the dependence of the influence on the main parameters of the electromagnetic field of the following factors: geometric dimensions of the air gap between the poles of the magnetic circuit and the heated flat body; the longitudinal edge effect caused by the open circuit of the magnetic circuit of the inductor, as well as the transverse edge effect associated with the appearance of the longitudinal components of eddy currents in a heated flat object. The solution of particular problems of LTIHS in one- and two-dimensional formulation allows them to be simplified and to perform calculations for various design variants of induction heating devices with a traveling electromagnetic field, using a one-dimensional model that explicitly takes into account the features of electromagnetic processes in the systems under study.

Optimization of Slab Edge in Roughing of Stainless Steel

To reach high demands of a stainless steel surface quality the location of a slab edge is optimized utilizing multiphysical finite element (FE) analysis. The slab edge forms in roughing process when the longitudinal edge of the stainless steel slab moves parallelly towards the center of a transfer strip surface due to several rough and edge rolling passes. Strip spreading and location of the slab edge are managed by edge rolling process which is accomplished concurrently with roughing. Deformation resistance has a significant role characterizing the strip spreading and material flow in the roll bite, thus experimental material compression testing was carried out and the results fitted to the Hensel-Spittel equation. Multiple edger roll profiles were designed, and the most feasible details of the roll profile were iteratively utilized for the new profiles. In this way the location of the slab edge was optimized closer to the edge of the transfer strip by developing a new edger roll profile and resetting edge rolling passes according to results of FE-simulations. To mimic an industrial-scale roughing process an automated pass schedule control was developed in the FE-model. Therefore, multipass simulations require only a pass schedule data to run simulation.

Linear asynchronous traction drive in urban rail and maglev transport systems

The development of transport infrastructure of large cities with high population density and development should be carried out on the basis of innovative technical solutions, that allow to simplify the conditions of laying of tracks, reduce the cost of construction, reduce noise, provide comfort to passengers and reduce the cost of operating rolling stock. One such solution, the effectiveness of which is confirmed by foreign experience, is the use of linear asynchronous traction drive (LATD) in urban rail and maglev transport systems. This, in particular, allows to increase the allowable value of slope paths to 6065, reduce the vertical dimensions of rolling stock to 3.15 m, reduce the diameter of the tunnel by 2530%. The release of the wheel pair from the function of the implementation of traction effort makes it possible to apply on the wagons the articulated semi-frames of trolleys, that ensures better rolling stock in curves, and as a result - less wear of wheels and rails and less noise. This article analyzes the advantages and disadvantages of LATD compared to the traction drive of traditional execution, considers variants of constructive performance of linear induction motors (LIM), processes of electromechanical energy conversion in LIM, the option of building a LATD control system is presented. The article examines the flat LIM, which have found use in the transport systems of major cities in Asia and America. The processes of energy conversion in LIM are distinguished by the presence of a longitudinal edge effect, which determines the distortion of the resulting magnetic field, which is manifested in the reduction of induction and the displacement of the peak of the induction distribution curve to the escaping edge of the inductor. This effect is particularly manifested in high-speed LIMs with high quality. When the linearity of the magnetic environment is allowed, the resulting electromagnetic force of the LIM can be considered as the sum of electromagnetic forces created by the main field, as well as the direct and reverse fields of the longitudinal edge effect. The edge effects reduce efficiency and power ratio of LIM. The article discusses ways to compensate for the edge effects, as well as an overview of the world experience of the use of LATD in rail and maglev transport systems. The advantages of LATD and the world experience of its use suggest that for urban transport systems at speeds of up to 100-120 km/h this drive can be a real competition to traditional urban rail systems.

A portable smartphone-based laryngoscope system for high-speed vocal cord imaging of patients with throat disorders (Preprint)

BACKGROUND Recently, high-speed digital imaging (HSDI), especially HSD endoscopic imaging is being routinely used for the diagnosis of vocal fold disorders. However, high-speed digital endoscopic imaging devices are usually large and costly, which limits access by patients in underdeveloped countries and in regions with inadequate medical infrastructure. Modern smartphones have sufficient functionality to process the complex calculations that are required for processing high-resolution images and videos with a high frame rate. Recently, several attempts have been made to integrate medical endoscopes with smartphones to make them more accessible to underdeveloped countries. OBJECTIVE To develop a smartphone adaptor for endoscopes to reduce the cost of devices, and to demonstrate the possibility of high-speed vocal cord imaging using the high-speed imaging functions of a high-performance smartphone camera. METHODS A customized smartphone adaptor was designed for clinical endoscopy using selective laser melting (SLM)-based 3D printing. Existing laryngoscope was attached to the smartphone adaptor to acquire high-speed vocal cord endoscopic images. Only existing basic functions of the smartphone camera were used for HSDI of the vocal folds. For image processing, segmented glottal areas were calculated from whole HSDI frames, and characteristics such as volume, shape and longitudinal edge length were analyzed. RESULTS High-speed digital smartphone imaging with the smartphone-endoscope adaptor could achieve 940 frames per second, and was used to image the vocal folds of five volunteers. The image processing and analytics demonstrated successful calculation of relevant diagnostic variables from the acquired images. CONCLUSIONS A smartphone-based HSDI endoscope system can function as a point-of-care clinical diagnostic device. Furthermore, this system is suitable for use as an accessible diagnostic method in underdeveloped areas with inadequate medical service infrastructure.

Simulation and optimization of the particle agglomeration in an aerodynamic agglomerator using a CFD–PBM coupled model

As an effective method to remove fine particulate matter (FPM) in coal-fired industries, the aerodynamic agglomeration has recently received increasing attention due to its application value. In this paper, a CFD–PBM coupled model of the particle agglomeration for industrial application was developed to predict the particle size distributions (PSDs) using Eulerian multiphase approach and Population Balance Model. Three kinds of particles with different inertia (i.e. inertialess, finite inertial, and inertial) and Brownian motion were considered, and a collision efficiency was induced to modify the kernel functions. Furthermore, the impacts of inlet velocity, initial particle concentration and flow field on the PSDs and the agglomeration efficiency were investigated. The results show that the agglomeration efficiencies of particulate matters with aerodynamic diameter [Formula: see text] 2.5[Formula: see text][Formula: see text]m and [Formula: see text] 10[Formula: see text][Formula: see text]m (i.e. PM[Formula: see text] and PM[Formula: see text]) both present logarithmic curves with the inlet velocity or the initial particle concentration. Under the working condition of the calculation, the optimal inlet velocity is in the range of 11–15[Formula: see text]m[Formula: see text][Formula: see text][Formula: see text]s[Formula: see text], and the optimal agglomeration efficiency of [Formula: see text] and [Formula: see text] is about 40%. The aerodynamic agglomerator is suitable for the traditional coal-fired power plants and cement plants, but it is not recommended when the initial particle concentration is less than 16.9[Formula: see text]g[Formula: see text][Formula: see text][Formula: see text]m[Formula: see text]. The analysis of the flow field shows that the longitudinal edge of the vortex and the windward side of the vortex generator are the main regions where particles agglomerate.

Topological edge and corner states in a two-dimensional photonic Su-Schrieffer-Heeger lattice

Implementation of topology on photonics has opened new functionalities of photonic systems such as topologically protected boundary modes. We theoretically present polarization-dependent topological properties in a 2D Su-Schrieffer-Heeger lattice by using a metallic nanoparticle array and considering the polarization degree of freedom. We demonstrate that when eigenmodes are polarized parallel to the plane of the 2D lattice, it supports longitudinal edge modes that are isolated from the bulk states and transverse edge modes that are overlapped with the bulk states. Also, the in-plane polarized modes support a second-order topological phase under an open boundary condition by breaking the four-fold rotational symmetry. This work will offer polarization-based multifunctionality in compact photonic systems that have topological features.

Numerical simulation and verification of MHD-vortex

Purpose The purpose of this study is research and development of the magnetohydrodynamics (MHD)-vortex technology. Design/methodology/approach The main instruments of research are mathematical modeling. For mathematical modeling used numerical and analytical both methods. For verification was made small copy of facility with forming of vortex in rotating magnetic field. Findings The design and manufacture of the industrial unit for melting small metal waste in a gas-fired smelt furnace has been completed. Originality/value Here shows new algorithm for engineering calculation of arc induction systems with take into account longitudinal edge effect and discrete distribution of current layers. Also shows verification of numerical results. Presented new MHD-technology for forming vortex in electromagnetic field.

Investigation of Wheelhouse Flow Interaction and the Influence of Lateral Wheel Displacement

The aim of this research was to improve the understanding of the complex flow featuresfound around a wheel and wheelhouse and to examine how the lateral displacement of the wheelaffects these features and the production of exhibited pressures and forces. A bespoke rotatingwheel rig and accompanying wheelhouse with a fully-pressure-tapped wheel arch was designedand manufactured at Loughborough University. Wind tunnel tests were performed where force andpressure measurements and Particle Image Velocimetry (PIV) data were obtained. The experimentaldata was used to validate unsteady CFD predictions where a k-! SST Improved Delayed DetachedEddy Simulation (IDDES) turbulence model was used in STAR-CCM+ (10.04.009, Siemens). The CFDshowed good agreement with all trends of the experimental results providing a validated numericalmethodology. For both methodologies, a lower amount of wheelhouse drag was found generatedwhen the wheel was rotating. However, the CFD showed that whilst this was the case, totalconfiguration drag had increased. This was attributed to an increase of the wheel and axle drag,illustrated by the change in separation over the wheel itself when located within a wheelhouseand so overcompensating the reduction in body and stand drag. Differences in vortex locationswhen comparing to previously-attained results were due to differences in housing geometry, suchas blockage in the cavity or housing dimensions. Experimental and computational results showedthat up until a 10 mm displacement outboard of the housing, overall drag decreased. The reductionin housing drag was credited to a reduction in the size of outboard longitudinal vortex structures.This led to the lateral width of the shear layer across the housing side being narrower. Overall, thisstudy identified that there were potential benefits to be gained when offsetting a wheel outboard ofthe longitudinal edge of a model housing.

FLAT ASYNCHRONOUS ELECTRIC DRIVE OF STONE MILL

In modern flour production, the preservation of all vitamins and minerals in it is relevant. Minerals and vitamins are stored in flour, ground from whole grains. In the stone mills, the grain is subjected to repeated exposure to the working surfaces of the millstones, as a result of which the flour contains a large percentage of the most important components of the grain. The stone mill’s drive should provide a low rotational speed of the mills (peripheral speed up to 10 m/sec.) and the possibility of smooth control of its speed and torque without reducing the performance of the mill. From this point of view, it is promising to use in the mill’s drive, instead of asynchronous motors, rotation with additional devices (gearboxes, belt drives, V-belt drives, etc.) of flat asynchronous electric drives. The article suggests possible variants of technical solutions for stone mills with flat electric drives. It was concluded that the use of a flat asynchronous motor in the mill’s drive allows not only smoothly adjusting the frequency and torque of the millstones, but also because of the presence of edge effects, to prevent flour sticking in the millstone working zone. Compiled with the possibility of solving by analytical methods a mathematical model of mill’s drive, based on a flat electric drives, taking into account the longitudinal edge effect, the strength of viscous (internal) and dry (external) friction. The mechanical characteristics of the drive were found when moving the flat electric drives inductors and the dependencies of the change in the mill productivity on the millstone rotation frequency when grinding various grains, changing the fill factor of the grinding zone and the gap between the millstones were obtained.