Systems to Control Molten Metal Transfer in Arc Welding

The paper analyzes the systems used for controlling molten wire metal droplets during the arc welding process in shielding gases. The variations for implementing the relevant systems are given, with the positive and negative aspects of such implementation taken into account. Electrical systems are currently investigated to the fullest extent possible and implemented in different power sources for pulsed welding arc. Mechanical systems are represented by different types of feeders that provide the pulsed wire feeding process. The feed mechanisms driven by electric motors and electromagnets are analyzed. In addition to the mechanical and electrical systems, the examples of combined control systems are given

Luminescence of Eu 3+ ions in hybrid polymer-inorganic composites based on poly(methyl methacrylate) and zirconia nanoparticles

Spherical nanoparticles of ZrO2 with 2 and 10 mol% EuO1.5 up to 20 nm size were prepared by the method of hydrothermal synthesis for luminescent functionalization of the polymer–inorganic nanocomposites based on poly(methyl methacrylate). Surface modification of oxide nanoparticles was carried out by 3‐(trimethoxysilyl)propyl methacrylate, dimethoxymethylvinyl silane and 2‐hydroxyethyl methacrylate to provide uniform distribution and to prevent agglomeration of nanosized filler in the polymer matrix. Polymer–inorganic composites were synthesized by in situ free radical polymerization in bulk. Structuring of ZrO2‐EuO1.5 nanoparticles in the poly(methyl methacrylate) was studied by very‐small‐angle neutron scattering. According to the results, the dependence of photoluminescent properties of ZrO2‐EuO1.5 nanoparticles on the content of lanthanide, the symmetry of the crystal field, surface treatment and the polymer matrix were established. A correlation was shown between Stark splitting in luminescence spectra of ZrO2‐EuO1.5 nanoparticles and their phase composition. Using MMT‐assay it was shown that composites based on poly(methyl methacrylate) and ZrO2‐EuO1.5 nanoparticles do not have cytotoxic properties, which makes it possible to use them as prosthesis materials with contrasted and luminescent imaging properties