Ceramic filters for multi-stage treatment of industrial and household waste

Results of studies focused on the creation of efficient ceramic filters for multi-stage treatment of industrial and household wastes based on natural alumosilicate and technogenic starting materials are presented. The influence of the individual components of the charge on the basic structurally sensitive properties of ceramic materials is established. Compositions of compounds for the fabrication of the carriage of filters with tubular configuration are considered.     

Effect of the mechanochemical treatment of peat on the composition of aromatic hydrocarbons separated from peat lipids

The studies of the composition of aromatic hydrocarbons in the lipids of peats of different degrees of conversion are reported. The chemical transformations of mono-, bi-, tri-, and tetracyclic aromatic compounds under the mechanochemical action on peat are considered.     

Pore structures of carbon materials based on naturally oxidized Kuzbass coals

Carbon materials prepared by the thermolysis of naturally oxidized Kuzbass coals of different ranks in the presence of potassium hydroxide at a KOH/coal weight ratio of 1 g/g were studied with the use of X-ray diffraction analysis and porosimetry. It was found that porous carbon materials with a developed specific surface area and a specific pore volume with the contribution of micropores from 35 to 70% were formed upon chemical activation with KOH regardless of selected precursors.     

Optical gas analyzer intended to monitor gas emissions in the atmosphere

The optical gas analyzer based on a semiconductor laser is proposed in the variant applicable for remote monitoring of methane emissions on territories with gas-transport systems. The optimized configuration of a gas analyzer, which allows more accurate control of gas emissions in the atmosphere, has been developed. An approach based on the use of an optical fiber amplifier is proposed to increase the range of action of such devices.     

Architecture of a multifrequency synthesizer with a high spectral efficiency on the basis of a dispersive surface-acoustic-wave filter

New possibilities of creating a wideband parallel multifrequency synthesizer with a high spectral efficiency are investigated. The synthesizer is based on a dispersive filter using surface acoustic waves (SAWs). Discrete spectrally distinguishable frequencies are synthesized with the help of derived theoretical relationships. SAW-based synthesizer characteristics (bandwidths, the number of carrier frequencies generated, frequency pulse durations, and efficiency parameters) have been analyzed.     

Analysis of start-retardation modes in high-power synchronous electric drives

The article analyzes the start-retardation modes of synchronous electric drives of high-power exhausters, which are accompanied by high starting currents, not only under a direct start, but also under control of electric energy flows from a semiconductor converter. A mathematical model of electric drive is proposed and substantiated for the analysis of transition processes of ac electric drives. This model has an electromechanical converter that constitutes the links with distributed parameters. A distinctive feature of the model is refinement of the magnetization characteristic of the magnetic-circuit steel, which was carried out during full-scale measurements of the variables of the synchronous electric drive with direct start of the exhauster. To check the adequacy of the mathematical model, the results of a full-scale test were compared with the simulation results by statistical methods using Student’s criterion. The computational results using the proposed model were compared with the calculations by the classical models with lumped parameters. It has been noted that, in the overload zone (for M > 1.5 MN) the calculated values differ considerably, with this being especially evident at low speeds. The obtained results can be recommended for selection of the parameters of semiconductor converters.