Search

New requirements put forward to the modern industry to reduce harmful emissions increase the utilization rate of metal, reduce the production time of equipment, the production of components and parts from hard-to-process materials aim to introduce new technological processes. A promising technology is additive growing, which allows one to minimize the production time of unique products, to use hard-to-process alloys, for example, based on the Ni-Fe-Cr system, in their manufacture. The study was carried out by the method of mathematical planning of the experiment with subsequent processing of the results on a supercomputer. The results of the influence of the current applied to the plasma torch and the flow rate of the plasma-forming gas are presented; wire feed rates during spraying in power plants per fraction and particle size ratio in the volume of the yield of suitable. The minimum allowable yield of the product is set at 30 % with the production of fractions in the range from 40 to 140 microns. The results obtained for the Inconel 718 alloy confirmed the possibility of obtaining Ni-Cr-Fe alloy powders. The mode proposed in the work allows obtaining commodity fractions at the level of 30-35% of the mass of the sprayed feedstock. Additional tests of the mechanical properties and corrosion resistance of samples made from the resulting powder showed satisfactory results, similar to the results of tests of samples made from heat-treated alloy forgings.

An experimental study on multicomponent mass transfer in the process of liquid-liquid extraction influenced by spontaneous interfacial convection (SIC) in the presence of a surface-active material is reported. The extractive systems, which investigated in the present study, are aqueous solution of potassium iodide/carbon tetrachloride and aqueous solution of potassium iodide/butyl acetate. Counter mass transfer of the components, acetic acid and iodine, were mainly studied and it has been observed that both the components mutually affect the kinetics of individual mass transfer. Presence of acetic acid, which is a surface active agent, beyond a critical driving force for mass transfer, induces spontaneous interfacial convection due to a development of gradient of interfacial tension along the interface of two extracting liquid. Interestingly, it was observed that in spite of the local disturbance developed due to SIC, counter mass transfer slows down the transfer rates of both the components in the system. The kinetic regularities of the mutual influence of the components on mass transfer are considered in the work. The work has significant values in understanding the kinetics of the multicomponent mass transfer and can be applied to selectively restrict the mass transfer of some components in a multi-component extractive system.

A mixed numerical-experimental technique based on vibration tests is modified and applied to determine the elastic material properties of woven composites. This non-destructive technique consists of physical experiments, numerical modelling and material identification procedure. For the purpose of characterization, two carbon fiber panels were prepared by manual layout technology. An evaluation of the accuracy of woven composite elastic properties is executed comparing the numerical and experimentally obtained resonant frequencies.

Existing processes of cleaning emulsion sewage are based on either physicochemical technology with application of complex of reagents – nonorganic electrolytes and organic flocculants, resulting in obtaining highly-mineralized purified water, which cannot be used for technical water supply, or based on complicated technologies of electrocoagulation and ultrafiltration. This required elaboration of a new technology and equipment for cleaning concentrated emulsion sewage, in particular, those containing emulsol of Wedolit EP-5 grade, used for hydro-mechanical expanders of electric-weld pipe lines. The technology stipulates a successive introduction of a reagent – suspension of alumo-silicate based hard-phased sorbent and solution of flocculant of cation type Praestol-650ВС – into emulsion sewage, their mixing with emulsion water in a definite mode, sedimental differentiation of the formed phases in a precipitator-flocculator “ЭП ОФ”, gravitation concentration and dewatering of the obtained sediment at vacuumfilter. The dewatered sediment can be utilized in cement industry and metallurgy. It was shown that application of the hard-phase sorbent does not result in an increase of mineralization of purified water and enables to use it for technical purposes. The group of companies “ECO-PROJECT”, Ekaterinburg, accomplished a project for Chelyabinsk pipe-rolling plant, elaboration and manufacturing of equipment, as well as commissioning and start-up of the equipment. The elaborated technical solutions in the process of equipment running showed a high efficiency and can be used as a base for creation of facilities of any productivity for cleaning multi-type emulsion sewage at enterprises of various industries.

In this paper, using the AA 511 alloy of the Al–Mg–Si system as an example, it is shown that the irradiation of aluminum melts with nanosecond electromagnetic pulses (NEPs) leads to a significant change in the nature of structure formation during crystallization, contributing to the refinement of the structural components of the alloy and the redistribution of alloying elements in them. It has been established that an increase in the frequency of irradiation of NEP melts is accompanied by the refinement of the structural components of the alloy, while the greatest degree of decrease in the grain size of the α-solid solution and intergranular inclusions of the eutectic Mg2Si phase is observed at an NEP frequency of 1000 Hz. An increase in the NEP frequency leads to a significant increase in the concentration of magnesium in the α-solid solution and the fragmentation of intergranular inclusions of the Mg2Si phase, which, when the melt is irradiated at a frequency of 1000 Hz, is released in the form of compact isolated inclusions. The processing of melts with NEPs leads to an increase in the Brinell hardness of the specimens in the cast state, as well as to a significant increase in the microhardness of the grains of the α-solid solution (from 38.21 in the initial state to 61.85 HV 0.001 after irradiation with a frequency of 1000 Hz). It is assumed that the effect of a pulsed electromagnetic field leads to a decrease in the critical values of the Gibbs free energy required to initiate nucleation processes and to a decrease in the surface tension at the “growing crystal–metal melt” interface, which causes a modifying effect on the alloy structure due to a decrease in the critical size nuclei of crystallization.

Background and Objectives: Here, non-thermal effects induced in the suspension of hollow alginate silver microcontainers after application of short electric field pulses (about 1 ms) of high intensity (about 1 kV/cm) were studied as a prospective tool for remote activation of microcontainers. Alterations in microcontaner’s shells were studied as a function of their composition. Magnetic nanoparticles immobilized within microcontainer’s shells were found to enhance effects that occurred after application of electric field pulses. Alterations found in microcontaner’s shells can be further employed for remote activation of microcontainers and release of encapsulated cargo. Results: The obtained results are the basis for further research of multifunctional microcontainers based on an organic alginate matrix and inorganic metal nanoparticles of silver and magnetite as drug carriers, the permeability, and structure of which can be switched using a non-thermal pulsed electrical action. Conclusion: The proposed microcontainers can be employed as carriers in new effective systems for encapsulation, targeted delivery, and controlled release of various substances in aqueous media responsive towards electric and magnetic fields which are promising in a wide range of biomedical tasks and other applications.

In this work, a study of the cases of destruction of the CuCrZr / 316L (N) bimetallic joint (BMJ) obtained by diffusion welding under conditions of hot isostatic pressing (HIP) was carried out. The identified defects are cracks propagating in the BMJ zone in the corner zone of the mock-ups of the heat-sink elements (HE). The analysis of the causes of destruction of the BMJ was carried out and the factors leading to the weakening of the BMJ zone are analyzed. The analysis of the thermal and stress-strain state of the HE mock-up during the manufacturing process was carried out. The study of the elements of the HE mock-up were carried out by methods of non-destructive testing (ultrasonic testing (UT)) and destructive testing (metallography; fractography; energy-dispersive X-ray spectroscopy; tensile tests). The inclusion of brittle phases in the zone of the BMJ was revealed and an assumption was made about the chemical composition of these phases. It was revealed that this line of brittle phases is a crack propagation zone in all cases of destruction of the BMJ in the HE mock-ups. The temperature range is revealed at which the effect of "ductility failure" of the CuCrZr is observed during the tensile testing of the samples.

The conditions for the synthesis of Al-Cr-W alloys during the aluminothermic reduction of a mineral tungsten concentrate - scheelite were considered. The alloys were identified as an aluminum matrix by the methods of elemental and X-ray phase analyzes. It is shown that the alloy synthesized from scheelite concentrate contains small amounts of iron and oxygen impurities (1.2 wt. %). It has been established that the alloys have a composite structure: inclusions of continuously solid solutions based on chromium and tungsten, as well as chromium aluminides Al3(Cr, W, Fe)2, which have increased microhardness values (12.9 GPa) are distributed in the aluminum matrix.

There is developed and manufactured a plasma atomizer allowing the production of powders of different metals. The analysis of structures of particle crystallization and its impact upon product properties is carried out.

By using a pendulum tribometer, an effect of lubricants having different nature and properties exerted on friction in an endoprosthesis pair based on a diamond-like carbon coating (DLC) and ultra-high-molecular-weight polyethylene (UHMWPE) has been studied. It is shown that, in contrast to the traditionally used natural formulations based on blood serum or hyaluronic acid, known as ones simulating the friction and properties in the natural synovial fluid, the artificial synovial fluid containing cholesterol liquid crystals inherent in natural synovia, together with compositions based on water-soluble chondroitin sulfates (glycosaminoglycans) containing the products of a cartilage matrix, exhibit much higher values of tribotechnical properties. At the same time, it is noted that the artificial synovial fluid containing cholesterol liquid crystals inherent in natural synovia has shown the best lubrication results, just as previous studies involving a natural cartilage–cartilage friction pair using a pendulum tribometer. This is also in a good agreement with the use of such lubricants for technical applications, in particular, for reducing friction between different solids, especially in metal-based friction assemblies, since they exhibit a high lubrication efficiency in different systems.

Compression diagrams were obtained and analyzed for monolayers composed from DOPC, POPC, DMPC, DPPC, DPhPC, and DMPS at the surface of solutions containing KCl, CaCl2, or BeCl2 and in the presence of polylysine (PLL) or chlorpromazine (CPZ). Elastic properties of monolayers are characterized by the area of lipid molecules, presented as an incompressible area with a soft shell, the size of which exponentially depends on the lateral pressure and the coefficient of elasticity. This assumption describes well the shape of the lipid compression diagrams, including lipids with saturated hydrocarbon chains (DPPC and DMPS) in the region, where they exhibit liquid crystal properties (liquid expanded state, LE). All lipids show changes in the interfacial Volta potential in this region; these changes linearly depend on the effective value of the work applied to compress the monolayer. Choosing for zero value of the Volta potential its magnitude at the point with a lateral pressure of about 1 mN/m, the slope of linear section of this dependence was estimated. The slope of this dependence makes it possible to identify different types of membrane-active compounds affecting the elastic and electrostatic characteristics of the monolayer. It turned out that this slope is practically independent of the pH and ionic composition of the aqueous subphase but decreases upon adsorption of PLL polypeptides on the surface of the DMPS monolayer. The adsorption of small positively charged CPZ molecules on this monolayer leads to the deviation in the potential vs work dependence from the linear. A quantitative description of this deviation is in a good agreement with the assumption that CPZ molecules are incorporated into the monolayer. Their contribution to the change in the energy of the monolayer and the Volta potential is determined by the amount of incorporated CPZ molecules, the effect of which on lateral pressure can be approximated by a function similar to the Boltzmann relation.

The addition of zinc phosphate tungstate to TsIATIM-201(Ciatim-201) and LZ-TsNII lubricants to improve their performance is considered. The addition of 2Zn(PO3)2.4WO3 to the dispersion medium of these lubricants improves their properties and hence decreases wear and operating costs.

The increasing technology of the optical elements surface strength on the example of mirrors coated with Al and Cu by applying carbon diamond-like nanostructures is developed. A method of pulsed la...

Nanopowders of the binary system of immiscible components Fe and Cu are synthesized by gas condensation of metal vapors. The structure and magnetic properties of nanopowders of various compositions are investigated, and their Mossbauer spectra are analyzed. It is shown that the method allows one to obtain nonequilibrium Fe(Cu) and Cu(Fe) solid solutions, in which the concentration of dissolved elements depends on the synthesis conditions.

Biopolymer sodium alginate (SA) is actively used as a green membrane material. To improve the pervaporation properties of the SA membrane in the isopropanol dehydration, different water-soluble fullerene derivatives with L-amino acids (threonine, hydroxyproline, and arginine) were used. In this study, fullerene–arginine derivative (C60-Arg) was shown to be an optimal filler acting both as a modifier and a cross-linking agent for SA. Different cross-linking agents (phosphoric and citric acids, calcium chloride) were tested for dense membrane cross-linking to reinforce the membranes for the separation of diluted solutions. Two types of membranes based on SA and SA/C60-Arg (5%) were developed: dense and supported on polyacrylonitrile substrate. The structural features of obtained membranes were investigated by the following methods: FTIR spectroscopy, scanning electron (SEM), and atomic force (AFM) microscopies. The optimal transport properties in dehydration of isopropanol (12–100 wt.% water) were found for the cross-linked SA/C60-Arg (5%) membrane supported on PAN substrate. The following parameters were obtained: 0.5–4.7 kg/(m2h) permeation flux and constant 99.99 wt.% water content in the permeate.

We study the light–matter coupling by Raman scattering in colloidal suspensions composed by core–shell TiO2@Silica (Rutile@Silica) nanoparticles suspended in ethanol and water solutions. Strong enhancement of the Raman signal per particle is observed as [TiO2@Silica] is increased above a threshold, being stronger in ethanol suspensions. Moreover, above this [TiO2@Silica] threshold, the optical transmittance of the ethanol suspension starts to be considerably lower than in water, despite scattering strength being higher in water. These results are attributed to localization of light induced by strong correlation in the scatterers’ position as a consequence of the long-range Coulomb interaction between the TiO2@Silica nanoparticles. Light diffraction in TiO2@Silica suspensions (water and ethanol) shows strong correlation in the scatterers’ position (structure seemingly cubic), being stronger in ethanol than in water (longer-range Coulomb interaction). As a result, we demonstrate in these colloidal suspensions for the first time, to our knowledge, strongly enhanced light–matter coupling through correlation-induced localization with klT much higher than unity and in an ordered colloidal-photonic structure. This strong enhancement of light–matter coupling by localization of light opens an avenue for manufacturing powerful sensing tools.

It is found that in inactivated vaseline oil, with the addition of oleic acid, the glass samples characterized by the destruction of the contacting surfaces and a significant increase in the coefficient of friction are set almost at the same load of 0.9 to 1.2 MPa. The addition of liquid-crystal cholesterol compounds to an inactivated lubricant during the friction of chemically inactive surfaces (glass) leads not only to a decrease in the coefficient of friction but also to an increase in the load capacity. For example, an additive of 3.0 wt % of the oleic acid cholesterol ester in vaseline oil increases the loading capacity by six to seven times when the glass is rubbed against the glass compared to the medium containing oleic acid. At the same time, using scanning electron microscopy and profilometry at loads of more than 4 MPa, the formation of microgrooves on the rubbing surfaces, which do not affect the characteristics and stability of friction, is established. The results obtained can be effectively used in the friction and processing of chemically inactive surfaces, such as glass, ruby, and diamond in the glass, watch, and diamond industries.

This article focuses on the experimental work supported by theoretical model of the multicomponent mass transfer during extraction driven by spontaneous interfacial convection (SIC). The regularities of individual and joint unidirectional and reciprocal mass transfer of components with different surface-active properties in the benzene-water extraction system at a flat phase interface are considered. The article demonstrates that both the diffusion and convective hydrodynamics of the flow affect the intensity of unidirectional and counter-mass transfer of the components under the conditions of SIC. Marangoni instability at the interface causes local convection, which enhances the mass transfer rate considerably. Experimental studies have shown that the joint unidirectional mass transfer of acetic acid and iodine from organic phase to aqueous phase under the conditions of SIC can be characterised by an increase in the iodine mass transfer coefficient in comparison with its individual mass transfer. It has found that with the acetic acid the unidirectional mass transfer of iodine can be increased by more than 20 times compared to its mass transfer without acid. However in case of counter-transfer of acetic acid and iodine, both the acetic acid as well as iodine mass transfer coefficients decrease compared to their individual mass transfer situations. The experimental data are in accord with the theoretical justification. A simplistic semi empirical theoretical model is developed for joint mass transfer, to estimate the coefficient of mass transfer of the components. The satisfactory convergence of the experimental and calculated data are shown.

Corrosion damage is one of the most frequent causes of accidents and damages of complex technical systems, including gas and oil refining systems. The work addresses the issues of the influence of structural factors on the development of intergranular corrosion in stainless chromium-nickel steels used for the manufacture of large-dimensional equipment installed outdoors. The transfer of processing plants to the northern regions has required a new approach to the reliability, durability and performance of both main oil and gas processing systems and auxiliary equipment. The paper considers the problems of corrosion damageability of materials of ejection devices for cooling circulating water with a significant content of highly aggressive chlorine compounds, sulfur and active oxygen, operating in cold climates. It is shown that an increase in the corrosion resistance of chromium-nickel steels operating under conditions of the Extreme North can be achieved by refining their chemical composition, which allows to regulate the content of elements that accelerate the occurrence of a tendency to develop corrosion defects. The effect of these defects on the change in the mechanical properties of nickel-chromium steels at normal temperatures and temperatures of climatic cold has been investigated.

Migration of gas and oil production facilities to remote northern regions of the country, increase in the unit capacity of the equipment set the task of increasing the service life and reliability of equipment for the extraction and transportation of gaseous and liquid media. One of the main reasons for the accelerated failure of equipment is the corrosion effect of transported media. In this work, the effect of corrosion under stress on the performance of the main metal and welded joints of stainless pipes of austenitic-grade chromium-nickel steels has been studied. It is shown that the rate of the anodic process increases as the level of plastic deformation increases and the rate of growth depends on the degree of imperfection of the structure of the material. It has been established that the heat-affected zones of assembly welded joints of austenitic steels are the most prone to corrosion cracking, and the requirements for restoring the structure of heat treatment of the weld are not fulfilled. Refusal of heat treatment leads to the appearance and growth of carbide particles in the structure of the heat-affected zone, which reduces almost by a factor of two, from 270 to 150 MPa, the level of stresses, leading to the occurrence of corrosion cracking in welded joints.

The paper presents the first data on the nitrogen isotope composition of the associated gases of mineral waters in the North Caucasus and newly acquired data on the carbon isotope composition of the CO2 and CH4. Most of the samples were taken from the high- $${{p}_{{{\text{C}}{{{\text{O}}}_{{\text{2}}}}}}}$$ waters of the Elbrus and Kazbek volcanic areas in the Greater Caucasus. It is shown that δ15N changes in the range of –3.9 to +5.6‰ and synchronously increases in gases of the Caucasus Spa Area (CSA) with an increase in the N2 and CH4 concentrations. This correlation points to a genetic association of non-atmogenic nitrogen with sedimentary methane-generating processes. The values of δ13С in carbon dioxide in the Elbrus area vary from –11.8 to –3.0‰. The mean value of δ13С (СО2) tends to increase north of Elbrus volcano, and this trend may be a consequence of the increasing content of СО2 produced by the thermal decomposition of sedimentary carbonates in the composition of gases, as well as a result of low-temperature interaction of the high- $${{p}_{{{\text{C}}{{{\text{O}}}_{{\text{2}}}}}}}$$ waters with the Jurassic and Cretaceous carbonate rocks. It is shown that high- $${{p}_{{{\text{C}}{{{\text{O}}}_{{\text{2}}}}}}}$$ waters associated with Elbrus volcano often contain up to 12.4% CH4. This methane is characterized by high δ13С of –32.0 to –17.2‰. Analysis of the distribution of concentrations and δ13С values of СН4 around Elbrus and the presence of N2 with positive δ15N values in the gases suggest a crustal genesis of the methane. The role of magmatic activity in this situation is reduced to producing a temperature anomaly that activates carbon isotope exchange in the CO2–CH4 system.

We report a study of upconversion luminescence in BaF2–HoF3 crystals in the visible spectral region under excitation to the 5I5 level of Ho3+ ions by laser radiation with a wavelength of 890 nm. For these excitation conditions, we propose mechanisms responsible for upconversion luminescence from the 5F3, 5S2(5F4) and 5F5 levels of Ho3+ ions.

The main parameters of the tunnel barrier of Josephson Nb/AlOx/Nb and Nb/AlN/Nb junctions are estimated in a wide range of the current density using the Simmons method. The dependences of the tunnel barrier height and width of the resistivity are determined experimentally for each type of the junctions. A decrease in the tunnel barrier height of the junction with the AlN interlayer by 0.3 eV as compared to an oxide junction enables us to obtain the junctions with a current density higher than 15 kA/cm2 at an insulating layer thickness of 10 A allowable technologically, which gives the possibility to obtain quality parameter Rj/Rn no lower than 25.

The aim of the study is to evaluate the volume activity of radioactive waste (RW) by surface and specific alpha contamination using portable gamma-spectrometry.Materials and methods. Methods of rapid assessment of the content of α-emitting radionuclides in solid waste of various morphologies using gamma-spectrometers based on germanium detectors are considered. Computational methods for determining the effectiveness of radionuclide registration are presented.Results. The possibility of using portable gamma-ray spectrometry to assess the surface and specific activity of various materials contaminated with α-emitters (232Th, 235U, 238U, 237Np, 239Pu, 240Pu and 241Am) is shown. The calculated values of the registration efficiency of low-energy gamma-emitters obtained by modeling the spatial-energy parameters of the detector are given.To simplify the solution of this problem, the calculation program used 20 standard templates of various geometries (rectangular, cylindrical, conical, spherical, etc.). The main sources of error in the survey of contaminated surfaces, largesized equipment and building structures were investigated.Conclusions. The possibilities of portable γ-spectrometry for estimating the volume of RW based on the surface density of contamination of materials with radionuclides of uranium and transuranic elements are investigated. When using γ-spectrometer with a high-purity germanium detector with a range of γ-quanta extended in the low-energy region, radionuclides such as 232Th, 235U,238U, 237Np, 241Am were determined by their own radiation or by the radiation of their daughter products.The “problem” element is plutonium, for rapid evaluation of which it is proposed, in accordance with the radionuclide vector methodology, to use 241Am, which accumulates during the β-decay of 241Pu.According to calculations, the most likely value of the activity ratio 239Pu/241Am for the object where the work was performed (scaling factor) varies in the range from 5.0 to 9.0.Based on the results of calculations and experimental studies, the parameters of the efficiency of registration of various α-emitting radionuclides by portable γ-spectrometers. It has been found that for germanium detectors with an absolute efficiency of registering a point source of 7÷15%, it is n×10–5÷n×10–4%.

The effect of the integrated shielding of plastic lubricants containing ethanolamines and liquid-crystalline cholesterol compounds induced during the frictional interaction of mating surfaces is found. It is shown that this effect of the protective antiwear properties of plastic lubricants significantly increases upon using intermediate refining fractions as a base—oil distillates, which form lubricant layers with low shear resistance due to the presence of natural surfactants and have high antiwear properties in the process of dynamic contact and interaction with ethanolamines and cholesterol compounds in contrast to refined mineral oils.

The formation of boundary lubricating films on the surface of steel during friction in the presence of substances forming complex compounds with iron — dipyridyl, o-phenanthroline, 8-hydroxyquinoline, and ethylenediaminetetraacetic acid, is considered. Boundary layers formed in the presence of complexones increase the antifriction properties of the lubricant at low loads. It has been established that surface films are formed predominantly from base oil molecules.

It was found that during the friction interaction of 45 grade steel on 45 grade steel, the behavior of the friction coefficient and temperature in the dynamic contact area directly depends ent the concentration of cholesterol esters in the lubricant medium and the contact time of the mating surfaces. It is noted that the lowest values of the studied values are realized with an increase in the concentration of cholesterol esters in the lubricant medium, namely, at their 100% concentration in the lubricant composition.

The research results on the effect of small additions of yttrium 0-0.3 wt.% on the structure, hardness, microhardness and distribution of elements in various structural components of chromium white cast iron are presented. It has been established that small additions of yttrium contribute to the grain refinement of the carbide phase and the formation of trigonal chromium carbide (Fe,Cr)7C3 in the structure of chromium white cast iron.

In this work, the thermal studies of ultrafine and nanocrystalline core–shell structures of Ti(Mo)C and Ti(Mo)C-Co formed in the process of plasma chemical synthesis according to the plasma condensation scheme in a low-temperature nitrogen plasma were performed. The oxidation processes of all phase components in the core–shell structures, determined during the high-resolution transmission electron microscopy studies, are presented as experimental results. The composition of nanocompositions before and after oxidation was recorded by X-ray methods. This allowed us to determine the sequence of interaction of the phase components of the core–shell structures with oxygen present in cylinders with argon, including carbon oxidation. In addition to the high-resolution transmission electron microscopy methods, the presence of carbon on the surface of particles was also confirmed by Raman spectroscopy. The use of these analysis techniques in combination with the results of derivatography and thermogravimetry made it possible to formulate the oxidation mechanisms of the core–shell structures of Ti(Mo)C and Ti(Mo)C-Co.

The resistance of aluminum alloys to the actions that are characteristic of operation in the load-bearing structures of bridge constructions, namely, fatigue, static, impact loads, and crack propagation, is studied. It is shown that, in bridge building, medium-strength aluminum alloys of the Al–Mg, Al–Mg–Si, and Al–Zn–Mg systems should be used. The specific features of deformation and fracture of aluminum alloys that affect their ductility, fracture energy, fracture toughness, and fatigue life are revealed.

A detailed granulometric analysis of native starches of various botanical origin was carried out: sorghum with a granule size of 3,5–21,7 μm and an average size of 11,0 μm, wheat with a granule size of 2,8–30,7 μm and an average size of 12,4 μm, rice with a granule size of 2,7–7,9 μm and an average size of 5,3 μm, triticale with a granule size of 4,0–30,7 μm and an average size of 13,2 μm, rye with a granule size of 4,9–42,8 μm and an average size of 21,2 μm, pea with a granule size of 6,1–32,3 μm and an average size of 20,4 μm, chickpea with a granule size of 6,0–25,6 μm and an average size of 14,8 μm, amaranth with a granule size of 0,5–1,5 μm and an average size of 1,1 μm, barley with a granule size of 3,0–21,4 μm and an average size of 10,9 μm, tapioca with a granule size of 2,8–31,2 μm and an average size of 10,6 μm, oat with a granule size of 3,96–14,91 μm and an average size of 7,39 μm, potato with a granule size of 7,7–60,0 μm and an average size of 21,7 μm, corn with a grain size of 3,6–19,2 μm and an average size of 9,8 μm, corn high amylose with a granule size of 3,3–11,65 μm and an average size of 7,11 μm, corn high amylopectin with a granule size of 4,26–18,26 μm and an average size of 9,94 μm, wheat from the «Shortandinskaya 95» variety With a granule size of 1,74–20,48 μm and an average size of 7,05 μm, wheat from the «Astana» variety with a granule size of 2,52–26,74 μm and an average size of 8,30 μm, wheat from the «Akmola-2» variety with a granule size of 2,43–26,22 μm and an average size of 8,11 μm. Based on the granulometric analysis of native starch, an innovative, highly effective, economical and environmentally friendly method of purposefully changing the physicochemical properties of native starches of various botanical origin was developed using the combinatorial method.

The characteristics of upconversion luminescence of CaF2:Er crystalline powders upon laser excitation of Er3+ ions to the 4I13/2 level at a wavelength of 1531.8 nm are studied. The upconversion luminescence energy yields for the spectral regions of 380–780 and 380–1100 nm are determined. It is found that upconversion luminescence of CaF2:Er powders with Er3+ concentrations of 0.5, 2, 4, 6, 8, 10, 11, 13, 15, and 17% is characterized by correlated color temperatures of 5100, 2142, 1726, 1738, 1773, 1757, 1762, 1765, 1735, and 1714 K, respectively.

Typically, closed-type impellers are more efficient than open-type impellers, but in the manufacture of closed-type impellers, cost of wheels is higher. This paper describes the development of cost-effective and simple impeller wheel for a fluid pump in the truck cooling system. To perform this task, the numerical computations of a standard impeller wheel were carried out, its characteristics were also obtained from a test bench, the standard impeller wheel model was verified. The open-type impeller wheel was developed according to the current dimensions of standard impeller wheel and then analyzed with the numerical computations by the software ANSYS CFX (Academic license) computational fluid dynamics. The developed open-type impeller wheel works very effectively in spite of performance degradation by 5% in comparison to the closed-type impeller wheel. When working as a part of engine, the pump efficiency is 0.552-0.579. The maximum value of the pump efficiency is 0.579, it can be achieved at the highest speed of the pump (4,548 rpm and 655 l/min).

Time- and site-specific release of bioactive compounds mediated by microcontainers immobilized on a surface is of high importance in a variety of tasks related to biomedicine and functional coatings. In the present work, we investigate arrays of hollow microchambers formed by composite shells based on a polylactic acid matrix and single-walled carbon nanotubes filler with high responsiveness towards electric current stimuli. The monitoring of the morphology changes reveals significant damages to the shells of microchambers formed by conductive composite material. The voltage of 3 V is shown to be sufficient to induce thermal damages to the microchambers. This study demonstrates the in-principle possibility to realize the opening of polylactic acid-based microchambers by application of low-power currents. The developed system opens a promising avenue for implantable delivery routes in a number of areas related to smart coatings, time and site-specific release. We believe these results will find application in the development of new implantable drug depot systems in biomedicine and cosmetology.

It was shown that the nanoindentation treatment of the atomically flat GaAs surface with the tip of atomic-force microscope in contact mode allows to produce small size pits with the depth in the range from a few tenths of nm up to a 1.5 nm. The experimental data can be qualitatively described on the base of kinetic concept of fracture of solid state developed by Zhurkov, which suppose the generation of defects and subsequent destruction of the GaAs surface. The molecular dynamics modelling confirmed thermally activated destruction of a few top atomic layers under indentation. The presented technology could be used to form the shape of solid state surfaces with subnanometer resolution in depth without wet etching processes.

Natural and synthetic polycations of different kinds attract substantial attention due to an increasing number of their applications in the biomedical industry and in pharmacology. The key characteristic determining the effectiveness of the majority of these applications is the number of macromolecules adsorbed on the surface of biological cells or their lipid models. Their study is complicated by a possible heterogeneity of polymer layer adsorbed on the membrane. Experimental methods reflecting the structure of the layer include the electrokinetic measurements in liposome suspension and the boundary potential of planar bilayer lipid membranes (BLM) and lipid monolayers with a mixed composition of lipids and the ionic media. In the review, we systematically analyze the methods of experimental registration and theoretical description of the laterally heterogeneous structures in the polymer layer published in the literature and in our previous studies. In particular, we consider a model based on classical theory of the electrical double layer, used to analyze the available data of the electrokinetic measurements in liposome suspension with polylysines of varying molecular mass. This model suggests a few parameters related to the heterogeneity of the polymer layer and allows determining the conditions for its appearance at the membrane surface. A further development of this theoretical approach is discussed.

It is known that organic and mineral films appear in microwave radar or optical aircraft/satellite images as the areas of reduced intensity due to suppression of short wind gravity-capillary waves (GCW) - slicks. The suppression of GCW with wavelengths ranged from some millimeters to decimeters can be characterized in terms of film elasticity. Hence, marine slicks in radar/optical images can be quantitatively described if the film elasticity is known. The elastic properties of monomolecular films have been thoroughly studied, while the problem for thick films, particularly for crude oil films remains poorly investigated. The latter are characterized by strong inhomogeneity in thickness. This paper is focused on laboratory analysis of GCW attenuation due to non-uniform films. The damping of GCW was measured in laboratory using a method of parametric excitation of standing GCW in a vertically oscillating cuvette mounted on a vibration table. Laboratory measurements were performed for highly inhomogeneous films of pure dodecyl alcohol. When the surfactant concentration exceeded the values corresponding to the saturated monomolecular layer, the surfactant excess was concentrated in non-spreading drops (lenses) of macroscopic thickness of 1-3 mm. The GCW attenuation coefficient was studied for GCW frequencies of 10 to 20 Hz and for different sizes and number of lenses. It was found that the attenuation coefficient increased with the relative area of the lenses. A physical explanation of this effect was proposed based on the “lens-wall” model, when assuming that the lenses reduced the area of the monomolecular film and, accordingly, increased the wave attenuation. Theoretical analysis of wave damping based on a “lens-wall” hypothesis has demonstrated good consistence with the experiment. The effective elasticity of a two phase film -a monomolecular layer with a lens phase- is introduced, which replaces the two-phase film with an effective monomolecular film.

Wide application of ultrafiltration in different industrial fields requires the development of new membranes with tailored properties and good antifouling stability. This study is devoted to the improvement of ultrafiltration properties of poly(m-phenylene isophtalamide) (PA) membranes by modification with titanium oxide (TiO2) particles. The introduction of TiO2 particles improved membrane separation performance and increased antifouling stability and cleaning ability under UV irradiation. The developed membranes were characterized by scanning electron and atomic force microscopy methods, the measurements of water contact angle, and total porosimetry. The transport properties of the PA and PA/TiO2 membranes were tested in ultrafiltration of industrially important feeds: coolant lubricant (cutting fluid) emulsion (5 wt.% in water) and bovine serum albumin (BSA) solution (0.5 wt.%). The PA/TiO2 (0.3 wt.%) membrane was found to possess optimal transport characteristics in ultrafiltration of coolant lubricant emulsion due to the highest pure water and coolant lubricant fluxes (1146 and 32 L/(m2 h), respectively), rejection coefficient (100%), and flux recovery ratio (84%). Furthermore, this membrane featured improved ability of surface contamination degradation after UV irradiation in prolonged ultrafiltration of BSA, demonstrating a high flux recovery ratio (89–94%).

Strong variability of Ka-band radar backscattering from short wind waves on the surface of water covered with surfactant films in the presence of internal waves (IW) was studied in wave tank experiments. It has been demonstrated that modulation of Ka-band radar return due to IW strongly depends on the relationship between the phase velocity of IW and the velocity of drifting surfactant films. An effect of the strong increase in surfactant concentration was revealed in convergent zones, associated with IW orbital velocities in the presence of a “resonance” surface steady current, the velocity of which was close to the IW phase velocity. A phenomenological model of suppression and modulations in the spectrum of small-scale wind waves due to films and IW was elaborated. It has been shown that backscatter modulation could not be explained by the modulation of free (linear) millimeter-scale Bragg waves, but was associated with the modulation of bound (parasitic) capillary ripples generated by longer, cm–dm-scale waves—a “cascade” modulation mechanism. Theoretical analysis based on the developed model was found to be consistent with experiments. Field observations which qualitatively illustrated the effect of strong modulation of Ka-band radar backscatter due to IW in the presence of resonance drift of surfactant films are presented.