This paper presents the results of studying the surface properties changes of a thermoregulating coating based on polystyrene and silica filler after proton irradiation with an energy of 50 keV at a ...fluence of 3 × 1015 cm−2. After proton irradiation, the values of the contact angle of wetting with water increase by 3.5% and 14.9% for polystyrene and the coating, respectively. The free surface energy (energy of the surface layer) of polystyrene and the coatings before and after proton irradiation was calculated using the Owens-Wendt-Rabel-Kaelble method. There was a significant increase in the polarity of the polystyrene surface (γp increased by a factor of 2.2) after proton irradiation. For the coating, an increase in γp by a factor of 3.89 was observed after proton irradiation. Structural changes in the coating were presented by IR Fourier spectroscopy. A slight decrease in the absorption intensity of all characteristic bands compared to the unirradiated sample was noted. It was found that the irradiation of the coating with protons led to the formation of macromolecules with hydroxyl, carbonyl, and carboxyl bonds, as well as the formation of dimeric and oligomeric siloxane chains. It was also found that after irradiation of a pure polystyrene sample with protons, the value of the solar absorption αs increased by only 4.2%; whereas for the coating with silica filler, the value of αs increased by 28.6%.
The paper presents data on the creation of polymer coatings based on a polystyrene binder and a silica filler. The resulting coatings were evaluated by using scanning electron microscopy, atomic ...force microscopy, and spectrophotometry depending on the content of the filler. The resistance of the coatings to electron irradiation with an energy of 50 keV (fluence of 6×1015cm−2) was studied. Electron irradiation of a coating with a silica filler leads to a significant increase in the surface roughness. The polystyrene binder possesses high radiation resistance; there is practically no increase in the integral coefficient of absorption of solar radiation (αs). After electron irradiation of a pure polystyrene sample, the value of αs increases by only 1.2% (Δαs=0.008), and for a coating with 60 wt% of the investigated filler, it increases by 3.9% (Δαs=0.010).
•Polystyrene (PS) coatings with silica filler were synthesized.•PS and coatings were exposed to electron irradiation with an energy of 50 keV.•The change in the optical properties after electron irradiation was evaluated.•After irradiation of pure PS, the value of αs increased by 1.2% (Δαs=0.008).•After irradiation of a coating, the value of αs increased by 3.9% (Δαs=0.010).
The placenta has a unique hypomethylated genome. Due to this feature of the placenta, there is a potential possibility of using regulatory elements derived from retroviruses and retrotransposons, ...which are suppressed by DNA methylation in the adult body. In addition, there is an abnormal increase in the level of methylation of the LINE-1 retrotransposon in the chorionic trophoblast in spontaneous abortions with both normal karyotype and aneuploidy on different chromosomes, which may be associated with impaired gene transcription using LINE-1 regulatory elements. To date, 988 genes that can be expressed from alternative LINE-1 promoters have been identified. Using the STRING tool, genes (NUP153 and YWHAB) were selected, the products of which have significant functional relationships with proteins highly expressed in the placenta and involved in trophoblast differentiation. This study aimed to analyze the expression of the NUP153 and YWHAB genes, highly active in the placenta, from canonical and alternative LINE-1 promoters in the germinal part of the placenta of spontaneous and induced abortions. Gene expression analysis was performed using real-time PCR in chorionic villi and extraembryonic mesoderm of induced abortions (n = 10), adult lymphocytes (n = 10), spontaneous abortions with normal karyotype (n = 10), and with the most frequent aneuploidies in the first trimester of pregnancy (trisomy 16 (n = 8) and monosomy X (n = 6)). The LINE-1 methylation index was assessed in the chorionic villi of spontaneous abortions using targeted bisulfite massive parallel sequencing. The level of expression of both genes from canonical promoters was higher in blood lymphocytes than in placental tissues (p < 0.05). However, the expression level of the NUP153 gene from the alternative LINE-1 promoter was 17 times higher in chorionic villi and 23 times higher in extraembryonic mesoderm than in lymphocytes (p < 0.05). The expression level of NUP153 and YWHAB from canonical promoters was higher in the group of spontaneous abortions with monosomy X compared to all other groups (p <0.05). The LINE-1 methylation index negatively correlated with the level of gene expression from both canonical (NUP153 - R = -0.59, YWHAB - R = -0.52, p < 0.05) and alternative LINE-1 promoters (NUP153 - R = -0.46, YWHAB - R = -0.66, p < 0.05). Thus, the observed increase in the LINE-1 methylation index in the placenta of spontaneous abortions is associated with the level of expression of the NUP153 and YWHAB genes not only from alternative but also from canonical promoters, which can subsequently lead to negative consequences for normal embryogenesis.
A comparative analysis of the diffuse reflectance spectra and their changes after irradiation with electrons with an energy of 30 keV of coatings based on polymethylphenylsiloxane resin and pigment ...powders of two-layer hollow ZnO/SiO
2
particles is carried out. The analysis is performed in situ in the range of 250–2500 nm. The samples are irradiated using a Spectrum space-conditions simulator. The radiation resistance of the studied coatings based on two-layer hollow ZnO/SiO
2
particles is estimated relative to coatings based on ZnO polycrystals by analyzing the difference diffuse reflectance spectra obtained by subtracting the spectra after irradiation from the spectra of the unirradiated samples. It is found that the intensity of the induced absorption bands in coatings based on hollow ZnO/SiO
2
particles is less than in coatings based on ZnO microparticles, and the radiation resistance when estimating changes in the integral absorption coefficient of solar radiation (Δα
S
) is twice as high. The increase in the radiation resistance is probably determined by the different nature of defect accumulation: in the case of solid microparticles, defects can accumulate inside grains; in hollow particles, the accumulation of defects can occur only within the thin shell of the sphere.
The way of neutralization of waste of oil-processing industry of receiving valuable secondary raw materials is developed for use in the construction industry. Optimization of process of interaction ...of withdrawal of production of additive (DF-11) with waste of the ground is performed. The method of liquidation of the map of viscous production wastes of additives is developed. The special collector of waste is developed for selection of waste from the card. The regression equation establishing connection between the number of the absorbed petrowaste and content in initial mix OPP, GP and KEKA, allowing to optimize composition of mix is received. The optimum maintenance of the components entering mix is defined.
Using the methods of advanced materials science, the structural-phase states and properties of multiple plasma-surfaced layers of the R2M9U steel formed in a shielding-alloying nitrogen environment ...on the 30HGSA steel are studied after its subsequent triple high tempering. It is found out that a framework-type structure is formed in the surfaced layer, wherein the base element is iron and the atoms of Mo, N, Cr, and V are localized in lengthy interlayers of the skeletal network formed by the carbide phase of different compositions. The atoms of Al are concentrated in the globular particles chaotically distributed in the surface layer volume. Both in the layer surface and in the zone of its contact with the substrate there are microcracks located along the phase boundaries. After the triple high tempering, the framework material structure is retained. A significant increase (a factor of 1.4) in the surfaced layer microhardness is revealed, which is attributed to the formation of a martensitic structure in the grain bulk, implying substructural strengthening of the material. The tempering is accompanied by a decomposition of the solid solution, followed by the formation of submicron-sized second-phase particles, indicating a dispersion strengthening mechanism.
The development of supersonic aircrafts should rely on advanced methods of flow control in order to improve the efficiency and reliability of the aircrafts. This article presents numerical simulation ...of energy supply to the incoming flow and simulation of the flow over bodies with hemispherical and conical nose parts. The numerical study was based on the model of an inviscid perfect gas described by the Euler equations which were solved by using the explicit unsteady Godunov's numerical scheme with the second-order accuracy.
Interaction of a body with an incident supersonic flow is considered. By using numerical and experimental methods, gas-dynamic parameters of the supersonic flow near the body are determined for ...various Mach numbers. Theoretical calculations of the supersonic flow around a body are carried. The mathematical models used in the calculations are verified by the results of experimental studies performed in the IT-1M hypersonic impulse tube of the aerodynamic laboratory of the Mozhaysky Military Space Academy.
Using the methods of advanced material physics, the structural-phase state of a layer of high-entropy high-speed non-equiatomic molybdenum tool steel formed by electric arc surfacing in a nitrogen ...atmosphere is studied. The thermodynamical and mechanical (elastic moduli) properties of the surfaced layer are examined in a temperature interval of 300–1400°C, and a phase-composition diagram is presented. It is observed that a temperature increase is accompanied by an α→γ polymorphic transformation, followed by a decrease in the content of carbide phases and elastic moduli.
The effect of modifying ZnO powders with MgO nanoparticles (with a concentration of 0.1–10 wt %) on their diffuse reflectance spectra in the region of 0.2–2.5 μm before and after irradiation with 30 ...keV electrons was studied. Modification of ZnO powder was carried out by MgO nanopowder with a concentration from 0.1 to 10 wt % using a solid-state method at a heating temperature of 650°C. X-ray diffraction analysis showed that with this modification method there is no formation of additional phases. It was shown that zinc oxide structure symmetry belongs to the
P
6
3
mc
space group; magnesium oxide, to the
Fm–
3
m
space group. The spectral reflectance of such powders in the visible region is over 90%. Under irradiation of original and modified ZnO powders, as well as the MgO nanopowder, by 30 keV electrons, a decrease in their reflectance is recorded in the entire studied region of the spectrum. It was established that modification with MgO nanoparticles at a concentration of 3 wt % leads to an increase in radiation resistance by a factor of 1.32 compared to unmodified samples. This effect is determined by the sink of radiation defects on the large specific surface area of nanoparticles.
PDF
