Comparison Study on High Force Density Linear Motors for Compressor Application

This paper presents the modular topologies of the dual-stator dual-winding permanent magnet (PM) linear motors for linear compressors used in the electrified transportation application. Compared to the conventional PM linear motor in compressor, the proposed modular model is designed with the same volume but a higher thrust force density and a further higher air pressure in air cylinder, which are competitive in the compressor industry. The proposed compact PM linear motors are constructed with tubular windings in both inner and outer stators, as well as the ring-type magnet in mover. Simulation results of motor characteristics are compared by three-dimensional finite element method (3D FEM). Finally, the prototypes of the proposed PM linear motors are manufactured and tested for the linear compressor application.

Analytic baby skyrmions at finite density

We study the baby Skyrme model in (2+1)-dimensions built on a finite cylinder. To this end, we introduce a consistent ansatz which is able to reduce the complete set of field equations to just one equation for the profile function for arbitrary baryon charge. Many analytic solutions both with and without the inclusion of the effects of the minimal coupling with the Maxwell field are constructed. The baby skyrmions appear as a sequence of rings along the cylinder, leading to a periodic shape in the baryon density. Linear stability and other physical properties are discussed. These analytic gauged baby Skyrmions generate a persistent U(1) current which cannot be turned off continuously as it is tied to the topological charge of the baby Skyrmions themselves. In the simplest non-trivial case of a gauged baby Skyrmion, a very important role is played by the Mathieu equation with an effective coupling constant which can be computed explicitly. These configurations are a very suitable arena to test resurgence in a non-integrable context.

In situ wavenumber–frequency modal decomposition of acoustic emissions

A new acoustic sensing capability, consisting of a flexible high-density linear piezoelectric sensor array coupled to a high-bandwidth interrogation device, is developed and applied to in situ wavenumber–frequency modal decomposition of acoustic emissions in plates. An experimental assessment of the capability is undertaken using acoustic emissions generated by a ball-drop impact on aluminium and composite panels. A new method for acoustic source localisation based on this new sensor array is described, and it is shown to be more accurate than a conventional multilateration technique using single-point piezoelectric receivers. The potential of this new capability for acoustic emission detection, location and possible quantification is discussed.

Features of the protection of winter wheat crops from weed rotation after sunflower

Goal. The of the research was to conduct field studies of new formulations of herbicides in winter wheat crops and to optimize the phytotoxic composition of tank mixtures consisting of different-spectrum active substances. Methods. In carrying out the work, general scientific and special research methods were used. Results. Species diagnostics of weed phytocenoses in winter wheat crops showed that high potential weed caused dominance in the agrophytocenoses of ragweed wormwood and sunflower scavenger. The deformation of the classic wintering type of weed was observed in the direction of the annual seed species composition. The phytotoxic properties of tank mixtures of Granstar Gold and Hammer herbicides and combined preparations were studied, their technical efficiency, the dynamics of depression and the death of weeds during the growing season were established, the individual resistance of certain types of weeds was revealed. A biometric analysis (crop density, linear growth, grain yield from an ear) of winter wheat was carried out depending on the toxicity of the herbicides. The scientific conclusion was made that the most effective mixture of herbicides was Granstar Gold 30 g/ha + Hammer 20 g/ha. Conclusions. As a result of the studies, it was found that winter wheat responded positively to reducing the degree of clogging by improving biometric and productive indicators. The yield of winter wheat grain is in a natural dependence on the degree of weediness of crops and phytotoxic effectiveness against weeds. The maximum increase in grain yield of 0.34 t/ha was achieved in comparison with the control when processing wheat crops of the winter mixture of herbicides Granstar Gold 30 g/ha + Hammer 20 g/ha.