Home – Home – Jornals – Advanced Search

This study determines the mechanical parameters of ABS plastic (acrylonitrile butadiene styrene) by subjecting plates of finite thickness (1-5 mm) to impact loading. A spherical lead particle with a mass of 0.45 g serves as the projectile. A series of experiments provides the basis for mathematical modeling performed with the Reactor3D software package. The results show that the 0.45 g spherical projectile perforates a 3.5-mm-thick ABS plastic plate at an impact velocity of at least 230 m/s. The required impact velocity for perforation ranges from 140 to 300 m/s for ABS plates with thicknesses of 1 to 5 mm. The parameters obtained in this study describe the behavior of finite-thickness plates under impact with an error of less than 5%.

This study assesses the potential for replacing expensive alloys with novel metal-matrix composites comprising more accessible materials. It compares the dynamic response of the widely used VT20 aviation titanium alloy with that of a 316L steel - A356 aluminum metal-matrix composite under impact loading.

This study investigates the mechanoluminescent properties of epoxy resin composites filled with SrAl₂O₄:Eu,Dy (SAOED) phosphor. The elastic modulus of this phosphor is measured. The relationships between the mechanoluminescent intensity and mechanical loading parameters are characterized. The composites exhibit repeatable mechanoluminescence under cyclic mechanical stimulation.

This review surveys the development of hydrophobic and anti-icing coatings fabricated by cold gas dynamic spraying. It discusses fabrication strategies for achieving high hydrophobicity and icephobicity with cold gas dynamic spraying, covering coatings based on polymeric, metallic, and ceramic materials. A key advantage of cold gas dynamic spraying is its ability to create coatings with complex microstructures that confer high hydrophobicity and icephobicity without the need for post-processing. The review also covers the fundamental theoretical models of wetting and the key factors governing surface icephobicity.

The effect of mineral components of brown coal on the efficiency of coal microparticle combustion under pulsed periodic exposure to laser radiation (1064 nm, 120 s, 3 Hz) has been studied. The experimental samples were pressed tablets with a density of 1 g/cm³. Under microparticle irradiation with the same doses, the burnt mass is larger in samples with higher ash content, which indicates the catalytic effect of the mineral part of coal on burnout rate. The morphology of the surface and transverse chips of the samples after irradiation was studied by scanning electron microscopy. It has been found that the fused drops of minerals are observed on the surface of high-ash samples, and the channels of burnt organic part are observed on the transverse chips, along with the formation of calcium oxide phase.

Results of the comparative gas chromatographic - mass spectrometric analysis of the structural-group and molecular compositions of nitrogen-containing basic compounds, isolated by acid extraction from the deasphaltisates of high-sulphur natural asphaltite and the liquid products of its conversion in supercritical water (SCW) at 400 °C and 40 MPa in the presence of potassium hydroxide are presented for the first time. The higher yield of the acid extract in conversion products in comparison with initial asphaltite suggests that an additional portion of low-molecular nitrogen bases is generated during the destruction of asphaltenes and resins of asphaltite under the process conditions. In both extracts, the compounds of homologous series of quinoline, thiophenoquinolines, benzoquinolines, benzothiophenoquinolines, benzoacridines, azapyrenes were identified. It has been determined for the liquid products of SCW conversion that the content of benzoquinolines and benzoacrydines with respect to quinolines increases by a factor of 1.5, and thiophenoquinolines - by a factor of 1.2. Furthermore, among most of the nitrogen base types, the fraction of unsubstituted compounds and/or compounds containing a smaller total number of carbon atoms in the aromatic ring substituents is observed to increase in the conversion products. A change in the content of nitrogen bases or their appearance in conversion products suggests the presence of such nitrogen- and nitrogen-sulphur-containing structural fragments in the molecules of resin-asphaltene substances (RAS) of natural asphaltite.

New efficient broad-spectrum preparations have been developed on the basis of the aqueous solution of Novochizol with the addition of Siberian pine bark extract (SPE) and usnic acid (UA), the substance isolated from the Usnea lichen genus. Optimisation of the procedures for fungicide extraction from plant raw materials has been carried out to reduce costs and obtain pure extracts in quantities sufficient to make complex preparations. During field experiments conducted in 2022-2023 in the Novosibirsk Region, we studied the effect of seed treatment with Novochizol forms with the addition of SPE and UA on the development of root rot and leaf diseases, growth processes and yield of spring wheat Novosibirskaya 31. The use of Novochizol + UA complex as the growth regulator contributed to the reduction of root rot in the phases of tillering and milky-wax ripeness by 53.3 and 41.6 %, and Novochizol + SPE complex by 25.0 and 37.0 %, respectively. When using the seed protectant Dividend Extreme, the corresponding indicators were 70.0 and 28.6 %, respectively. The above-mentioned Novochizol + UA, Novokhizol + SPE complexes and the Dividend Extreme preparation showed effectiveness against septoria, which was 65.0, 66.7 and 67.7 %, respectively. Seed treatment had a positive growth-stimulating effect on such parameters as sprout formation, tillering, biomass accumulation, plant density, height and area of the flag leaf, and significantly improved ear structure indicators. The effect of the form of Novochizol with the addition of UA was more pronounced. Seed treatment provided an additional yield relative to the control (2.7 t/ha) at the level of 0.3 t/ha when using Novochizol + UA and 0.2 t/ha when using Novochizol + SPE or the fungicide Dividend Extreme.

Computer models of tetra-n-alkylammonium tetrafluoroborates have been developed. The transport, structural, and thermodynamic properties were studied over a wide temperature range. It is shown that under the conditions of a model experiment, crystallisation processes in the organic salts under consideration are kinetically inhibited, and the models remain in a glassy state in the temperature range from the melting point to 300 K. The diffusion coefficients in the molten state are in accordance with the experimental results, and are within 10^-7-10^-8 m²/s.

The scheme of phase formation in Fe-Pt nanoalloy was established using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), including in situ heating, small-angle X-ray scattering (SAXS), and optical emission spectrometry with inductively coupled plasma (ICP-OES). The nanoalloy particles were synthesised using the co-reduction of precursor solutions (Fe²⁺ and [PtCl₆]^2-) with an alkaline solution of hydrazine hydrate. To determine the scheme of solid Fe-Pt phase formation, the reduction process was stopped after 10 and 300 s by diluting the reaction mixture with cold (2 °C) water. Comparison of the results obtained using XRD, XPS, SAXS, and ICP-OES methods allowed us to establish that the formation of the solid phase under reduction-oxidation reaction conditions is a staged process. The first and fastest stage is the formation of the Pt-phase with particle sizes ≈3 nm. The second stage involves the joint reduction of platinum and iron precursors on the surface of Pt particles formed at the first stage. The last stage is the formation of ultrafine particles enriched in Fe under the conditions of Pt precursor deficiency.

Physicochemical characteristics of thermolysis oil obtained from polypropylene have been determined. The hydrocarbon composition, studied by two-dimensional gas chromatography and high performance liquid chromatography, as well as calculation of the iodine value, shows that the major components of the resulting oil are isoalkanes and alkenes. The results obtained allow us to draw conclusions about the mechanism of polypropylene transformation during thermolysis, and data on the fractional composition, density and viscosity further characterise thermolysis oil from the perspective of a petroleum product.