Using methods of the scanning electron microscopy, Raman scattering of light(RS), and electron paramagnetic resonance (EPR), consistent research of the local structure and magnetic features of different types of raw coal samples from Donetsk basin is carried out. It is established that the ratio of the main peak intensities of RS spectrum D and G is inversely related to the volatile substance amount Vdaf in the coal samples. The study of the kinetic behavior of the EPR line width in hydrogen, oxygen, and methane sorption-desorption processes in each coal sample helped determine that the diffusion coefficient value for hydrogen in coal at room temperature is equal to DН = (2 ÷ 7) × 10−5 cm2/s. It is demonstrated that the oxygen diffusion occurs with time according to two different exponential laws with diffusion coefficients DO,1 = 5 × 10−6 cm2/s and DO,2 = 5.5 × 10−7 cm2/s, respectively. The smaller coefficient corresponds to the diffusion caused by the hopping process. Finally, it is established that the anthracite is a unique type of coal which does not possess the ability “to conserve” the significant EPR line width after oxygen pumping out from the samples.

The challenges facing the development of environmentally friendly dry cutting technologies for various materials is investigated. The system used for the study includes a cutting tool equipped with inserts from layered composition ceramic with nano-scale multilayer coatings, an ionized gas medium which is supplied into the zone of cutting and the ultrasonic vibrations, which are placed to a cutting tool in the direction of the cutting speed. It is shown, that elaborated ecologically friendly dry machining not only does not match efficiency of standard machining technology with application of cutting fluid, but also in some cases surpasses it.

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The internal structural organization and phase composition of a fragment of the Chelyabinsk meteorite have been studied using neutron diffraction, tomography methods, optical microscopy, and Raman spectroscopy. The bulk mineral composition of the meteorite and spatial distribution of different components were determined. In addition to previously found phases of olivine, orthopyroxene, plagioclase and troilite, the obtained data of optical microscopy and neutron diffraction provide evidence of the presence of kamacite phase in the studied meteorite fragment. The heterogeneous distribution of the iron in the olivine and orthopyroxene phases was observed, the morphological calculations were used to analyze the spatial arrangement of metal components.

PhySicAl AND chemicAl TrANSformATioNS iN GAS coAl SAmPleS iNflueNceD by The weAK mAGNeTic fielD Purpose. To study changes in the gas coal sample microstructure, the trends of changing iron concentration and thermal effects of chemical reactions stimulated by the pulsating magnetic field of low intensity. methodology. This study used the experimental research methodology, mathematical treatment of the results and analytical methods including Xray fluorescence spectroscopy, differential thermal and thermogravitational analysis, Xray diffraction anal ysis and coal microparticles distribution by fractions, and others. findings. Treatment of gas coal samples with weak magnetic and electric fields showed that destructive processes in coal can be initiated both by electric and magnetic fields of weak density. The phase transitions and thermal effects in coal under changing temperature, coal mass changes during heating were defined; temperatures of exothermic and endothermic processes and the en thalpy of new substance formation were evaluated. The microparticle size distribution depending on the treatment method was analyzed. originality. It was shown that the iron concentration in recovered gas coal increases with decreasing the grain microparticle size to a limit value corresponding to the iron ash concentration. As a result of the influence of a low intensity pulsating magnetic field strength on the premechanically activated carbon microstructure, the microparticle size increases and, in general, their size range significantly expands. The minimum amount of absorbed heat is required for the chemical compound formation in mechanically activated coal, and the maximum amount is needed for mechanical activation followed by magnetic field treatment that, in the latter case, can be related to additional implementation of spinselective chemical reactions directly on the coal microparticle surfaces. Practical value. The obtained experimental results emphasize the fact that weak magnetic fields actively participate in coalifica tion. The results of experimental research can be used in the development of magnetic methods for coal outburst suppression.