Table of contents

XVI International Conference of Students and Young Scientists "Prospects of Fundamental Sciences Development" (PFSD-2019) conf-prfn.org

23-26 April, 2019

Tomsk, Russia

The XVI International Conference of Students and Young Scientists "Prospects of Fundamental Sciences Development" (PFSD-2019), held on 23-26 April, 2019 in Tomsk, Russia, is an annual multidisciplinary conference gathering together students, young researchers, post-docs, and experienced researchers working in the different research areas in order to facilitate aggregation and sharing interests and results for a better collaboration.

The conference received more than 140 submissions. After a rigorous peer-review process, 80 papers were accepted. The accepted papers cover the following conference topics: (1) Chemistry: synthesis and properties of functional materials; physicochemical analysis methods for materials; nanomaterials; ecology; organic synthesis; catalysis and petrochemistry; (2) Construction methods and materials; (3) Physics: condensed matter physics; surface physics; accelerator physics; hydrogen energetic; geophysics; modeling of physical processes; (4) Fundamental Medicine: cell biology, biochemistry; microbiology, biophysics, biomaterials; (5) Mathematics & IT: mathematical modeling and data analysis; mathematical methods in physics, chemistry, medicine, computational mathematics, differential equations, automated data processing and control systems, electronics; optoelectronics and nanophotonics; plasma emission electronics.

We are very grateful to all reviewers, both local and international, for their time and effort in reviewing the papers. Their feedback to the authors has been excellent and useful to ensure the high quality of papers for the conferences.

The Organizing Committee of PFSD-2019 thanks Universities involved in the conference organizing and Sponsors for their financial support, as well as everyone who contributed to the organization of this event and to the Proceedings publication.

Chair of the PFSD-2019 Organizing Committee: Prof. Irina Kurzina

Editors of the PFSD-2019 Conference Proceedings: Dr. Mikhail Semenov and Anna Bogdan

All papers published in this volume of IOP Conference Series: Materials Science and Engineering have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

The paper studies oxidative desulphurization of oils with an initial sulphur content of 1.98 wt% by hydrogen peroxide on a carbon-black (CB) catalyst coated by a combination of cobalt and nickel. The results demonstrate the effects of temperature and duration of the process, amount of the catalyst and the nature of the selected extractant on the removal efficiency of oxidized sulphur compounds. The extractant was represented by a solution of dimethylformamide (DMF) with water (10 vol%). The maximum removal degree of sulphur exceeded 70% and was achieved in 90 minutes with an amount of the catalyst of 1.0–1.3 wt.% and a temperature of 50 °C.

The effect of the nature of the silicon source on the physicochemical properties of synthesized zeolites and the activity of Zn-containing catalysts prepared on their basis in the course of conversion of the propane-butane fraction into aromatic hydrocarbons is studied. It is shown that the silicon source plays an important role in the hydrothermal synthesis of zeolite. It has an effect on the duration of synthesis but its effect on the physicochemical characteristics of the resulting product is minor. It is established that the activity and selectivity of Zn-containing catalysts for the aromatization of lower alkanes are practically independent on the nature of the silicon source used in the synthesis of the high-silica zeolite, which is an acid carrier of these catalysts.

The spectral-luminescence characteristics of binuclear bis(BODIPY) complexes in cyclohexane and ethanol, which exhibit different photophysical and photochemical properties in these solvents, have been investigated. It has been shown that the difference in spectroscopic properties is due to intermolecular interaction of the excited molecules with solvation shell. The possibilities of practical use are discussed.

The authors obtained two-phase samples of silver- and zinc-modified hydroxyapatite (AgHA, ZnHA) by liquid-phase deposition under microwave exposure; the main phase for all samples was hydroxyapatite Ca₅(PO₄)₃(OH) with hexagonal syngony. The parameters of the elementary lattice of HA were studied via X-ray phase analysis and confirmed the formation of solid substitutional solutions while modifying HA with silver and zinc ions. Solubility has been estimated at 20 ºC for a 0.9% NaCl solution; specific surface area and porosity have been estimated for ZnHA powders obtained in presence of aminoacids. Surface morphology and dispersiveness have been studied for AgHA and ZnHA powders. Hammett method helped to establish the presence of acidic and basic centers on the surface of ZnHA and AgHA. Koch biotesting showed HA, AgHA, and ZnHA acting as inhibitors thus affecting E. coli tested samples. HA, AgHA, and ZnHA powders can be recommended for medical purposes.

In this paper we synthesized high entropy oxide system (Sc_0.2Ce_0.2Pr_0.2Gd_0.2Ho_0.2)₂O_3±δ by precipitation of hydroxides from REE nitrates aqueous solutions and annealing the mixture at 800 °C. It is possible to obtain the various forms of simple and complex composition based on the rare earth oxides, including oxides in the form of nanosized powders. The main idea of obtaining HEOS comes from the field of high-entropy alloys. The interconnection between configurational entropy and mixing enthalpy is a key factor for determining phase transformations. The phase composition, structure, and surface morphology of the obtained powders were investigated by scanning electron microscopy and X-ray phase analysis methods.

Composites based on a porous hydroxyapatite carcass with a coating of PLGA were obtained. According to the SEM images, it was found that, the composites had a different coating character depending on the porosity of the HA framework. After 1 week, the dissolution rate of composites increases relative to pure PLGA, and the growth is proportional to the increasing of the amount of pore-forming agent in the material by 20-50%. The dissolution rate of HA in the composition of materials also increases since the second week, because the diffusion of the solvent in the HA increases as the result of PLGA hydrolysis.

This work is dedicated both to investigation of the influence of different conditions on the molecular weight characteristics of poly- ε-caprolactone (PCL) and to the synthesis of composites based on PCL and hydroxyapatite (HA) by in situ and mechanical mixing methods. It was shown that in situ synthesis is accompanied by chemical interactions between PCL and HA that were confirmed by IR spectroscopy and thermal analysis. The morphology of in situ obtained composites has more homogeneous and regular distribution of HA particles in the polymeric matrix than composites synthesized by mechanical mixing of HA and PCL.

The results of the research of the process of metals extraction from titanomagnetite ore are presented. The experiments were conducted in PVC columns. The most efficient metal recovery is achieved at a hydrofluoric acid concentration of 4 mol/L and ammonium fluoride concentration of 0.42 mol/L. This represent approximately 10% for titanium, iron and vanadium. Selectivity on titanium during percolation of a solution with a hydrofluoric acid concentration of 1 mol/L and ammonium fluoride of 2.5 mol/L is observed.

The effects of precursor and the method of support modification on the properties of supported metathesis catalysts for reaction of ethylene and trans-butene-2 into propylene are considered. The objects of the research are the catalyst comprising γ-Al₂O₃-supported molybdenum oxide as well as the modified alumina-based supports. The Mo precursors used is shown to significantly affect the state of the supported component. The distribution and morphology of the particles of active component inside the pores of the support differ for the ZrO₂-modified samples prepared by impregnation and wet mixing methods.

Silver/palladium composite nanoparticles (NPs) obtained by pulsed laser ablation in liquid (PLAL) technique catalyze oxidation of propylene glycol (PG) to lactic acid (LA) in alkaline media. The PLAL technique allows obtaining silver/palladium NPs with different silver/palladium molar ratio. Addition of palladium increases PG conversion (up to 52%) and LA selectivity (up to 88%). The reaction temperature and silver/palladium molar ratio strongly affects the catalytic activity of the silver/palladium composite NPs.

This paper deals with theoretical investigation and experimental verification of adsorption dynamics (kinetics) of water vapor on aluminium oxide material. Influence of vapor flow rate and grain size of the adsorbent on adsorption dynamics was carried out on a laboratory equipment using McBain-Bakr quartz balance. The flow rate at which there is no influence of external diffusion limitations was determined. The material was characterized by the BET method and X-ray phase analysis (XRD). The theoretical effective diffusion coefficient was predicted from the known structure of the adsorbent. Mathematical modeling of the mass transfer rates are based on a quasi-homogeneous model was performed. A comparison between theory and experiments for the various grain size adsorbent samples allows to determinate of the effective diffusion coefficient D_eff.

A simple method to assess adhesion properties of organic coatings by Ω parameter was developed and tested, where Ω is a ratio of indentation speed at a linearly increasing normal load to a resulting force on the indenter at the end of plastic deformation, when the indenter reaches a substrate. A relationship between Ω parameter and a coating hardness H determined by Oliver and Pharr method is shown.

The paper proposes a systematic approach to the elaboration of a structured mathematical model and modeling of chemical and technological systems under uncertainty exemplified by a sulfur production unit. The novelty of the suggested method lies in the choice of a suitable model type for each element of the system based on the systematic analysis, development of the selected model type and their merger into a unified system of models. The method was successfully implemented to construct a system of models for major units of the catalytic reforming plant at the Atyrau Oil Refinery (Republic of Kazakhstan). The study compares existing results, modeling results based on the suggested method and experimental results obtained using an LG-setup of the Atyrau Oil Refinery. The deliverables demonstrate high efficacy and excellence of the approach to the modeling of interconnected equipment (chemical and technological systems).

Nowadays air and water pollutions are becoming a serious problem for urban environment. One of the efficient methods of purifying water and air is photocatalysis on TiO₂ films. In this work, we obtained composite materials based on TiO₂ and modified by Ag and SiO₂ on the surface of the fiberglass material (Ag/SiO₂/TiO₂/FGM) by a sol-gel method. Complex studies were carried out to identify the phase compositions, morphology and textural characteristics of obtained samples by X-ray diffractometey, scanning electron microscopy, micro-X-ray spectral analyses and analysis of N₂ adsorption-desorption isoterms. Surface area and average pore size of this sample is 8.2 m²/g and 11.4 nm respectively. Prepared composite Ag(0.5%)/SiO₂(3%)/TiO₂/FGM material revealed photocatalytic activity in model reaction of methyl orange azo dye photodegradation under UV-irradiation.

The urgency of creating new efficient catalysts for the processes of deepening oil refining rises on the background of stricter requirements for the quality of motor fuels, as well as the deterioration of the quality of crude oil for processing, and an increase in the number of distillates of secondary processes involved in the production of commodity petroleum products. In this work, alumina-catalytic systems were synthesized using polyoxomolybdate compounds. The morphology, structure and phase composition of the synthesized catalytic systems were studied using the following analysis methods: scanning electron microscopy, microelement analysis, X-ray phase analysis, X-ray diffraction, electron spectroscopy. It has been established that the Mo / AI₂O₃ system is active in the process of thermal catalytic conversion of heavy residual raw materials.

This paper summarizes the experimental work done on the effect of petroleum resins on the process of relaxation the structural and rheological properties of petroleum paraffin solutions treated in ultrasonic field.

A combined treatment of petroleum paraffin solutions including 22 kHz ultrasonic exposure and addition of petroleum resins (0.3% 0.6% 0.9% by weight) was carried out. The addition of petroleum resins into the treated solution depresses the crystallization of hydrocarbons and favours the reduction of structural-mechanical characteristics of the system. The transition of the excited state of systems after the removal of the ultrasonic load to an equilibrium state occurs in time, and the nature of the change in the rheological characteristics and microstructure of paraffin crystals depends on the composition of the dispersion medium. It was revealed that trace amounts of resins introduced into paraffin oil systems treated with ultrasound will reduce their viscosity and improve transportation of hydrocarbons for 2 days at minimal cost.

The acidity of donor-acceptor complexes of boric acid with glycerol and sorbitol has been studied in aqueous solutions using pH-metry and electrical conductivity methods. A theoretical model of donor-acceptor acid-base equilibria in boric acid – polyol – water systems has been created. The constants of polyol boric acids formation and ionization were determined. The constants of glycerol and sorbitol boric acids formation were 0.05 and 0.06 l²·mol⁻², and those of glycerol and sorbitol boric acids ionization were 7.1·10⁻⁶ mol·l⁻¹ and 3.2 · 10⁻³ mol·l⁻¹, respectively. The systems studied were used to create new oil-displacing compositions for enhanced oil recovery.

Was studied how preparation method influences phase composition, oxide particle size and catalytic activity of the binary NiO–ZrO₂ systems. The processes taking place under the thermal influence while NiO–ZrO₂ catalysts are formed from precursors, obtained using a variety of methods, were determinated using the methods of simultaneous TGA-DTG/DSC analysis and XFA. Was studied the influence of the precursor preparation method upon the catalysts' phase composition, sizes of the nickel oxide and zirconium dioxide particles. The research revealed that preparation of precursor using coprecipitation method makes it possible to obtain a binary system, where nickel oxide has minimal size, determined by CSR, and monoclinic phase prevails in ZrO₂, after heating it to 800 °C. The research unearthed that the catalyst exhibiting maximal catalytic activity by deep oxidation of methane is nickel oxide-zirconium dioxide, containing equal amounts of monoclinic and tetragonal phases of ZrO₂.

Physicochemical and catalytic properties of 4.0% Mo/ZSM-5 catalysts manufactured on the basis of zeolites with a hierarchical pore system are investigated. The effect of the conditions of synthesis of zeolites with an additional mesoporous structure on their textural and acidic characteristics is studied. The structure and morphology of crystals of synthesized zeolites and catalysts produced from them are determined by the methods of X-ray diffraction analysis and high-resolution scanning transmission electron microscopy. It is shown that 4.0% Mo/ZSM-5 catalysts produced from zeolites with a mesoporous structure exhibit higher activity and stability in the course of methane dehydroaromatization.

The paper deals with the study of the effect of peat mechanoactivation on the structure and biostimulating and detoxifying properties of isolated humic acids (HA) in of oil-contaminated soil. It is shown that the mechanical activation of peat leads to an increase in the HA yield by a factor of 2-3. In this case, the changes in the fragment composition of HA are observed. Hence, the percentage of aromatic and oxidized alkyl fragments increases, while the amount of oxygen-containing functional groups decreases. The binding of petroleum organic compounds occurs due to the presence of an aromatic skeleton in the structure of HA. The increase in the proportion of aromatic fragments in the structure of mechanically activated HAs increases their affinity for hydrophobic oil compounds, thereby providing them a detoxifying ability. The maximum detoxifying ability of mechanically activated HA determines their biostimulating properties in the wheat seed germination experiment. The biostimulating effect from the use of mechanically activated HA samples is manifested itself to a greater degree in the increase in the height of the sprout stem and the dry mass of the aerial part of the plant. The processes of biodegradation of oil in the soil in the presence of HA are investigated. It is shown that the amount of bitumoids extracted from the soil in the presence of HA is reduced by 30%. The content of hydrocarbons in bitumoids decreases by 50% due to the biodegradation of low molecular weight alkanes. At the same time, the degree of branching of hydrocarbon chains increases, which suggests a microbiological activity. An increase in alcohol-benzene resins in the composition of bitumoids indicates the stimulation of hydrocarbon-oxidizing bacteria by humic acids. According to the data of IR spectroscopy, the content of paraffin hydrocarbons has decreased during the destruction of oil by soil microflora.

An oil-displacing system of prolonged action with adjustable viscosity based on surfactant inorganic acid adduct and polyol is created with the purpose to increase the efficiency of flooding or thermal steam formation treatment and to enhance oil recovery. The laboratory studies of physicochemical, rheological, and filtration characteristics of the system under natural exploitation conditions and thermal-steam treatment are presented. In 2014-2018 the field tests of the technology for enhanced oil recovery were successfully carried out using an acid oil-displacing system at the experimental sites of the Permian-Carboniferous reservoir of the high-viscosity oil of the Usinsk oilfield.

The problem of processing vacuum residues is relevant due to the enhancement of heavy crude oil recovery. The processing of fuel oil and vacuum residues is complicated due to the high content of resins and asphaltenes present in them. In order to develop new approaches to the processing of vacuum residues, it is necessary to comprehend the mechanisms of thermal degradation of high-molecular-weight oil components. Three samples of high-sulfur vacuum residues are cracked at a temperature of 500 °C and with a various process duration. The characteristic changes in the material and fractional composition of the products of the vacuum residue cracking depending on the process conditions are shown. It is found that the ratio of light to medium distillates in the composition of the products depends on the duration of cracking.

The article presents the results of investigation of potentiometric titration of the working solution containing Zn(II) and Cu(II) by sodium diethyldithiocarbamate (NaDEDC) using carbon composite electrode as the indicator electrode. The proposed method for the separate determination of copper ions (II) and zinc (II) under the joint presence was tested on data from titration model of binary mixtures and the real object. The titration curves were processed by the linearization method based on the transformation of a titration curve into the multiphase linear regression, whose parameters determine the equivalence point with high accuracy.

The paper presents the research results of physicochemical characteristics, adsorption kinetics and value of adsorption capacity with respect to water vapors of the aluminum-oxide adsorbent modified with potassium and sodium cations. It was shown that modification of desiccants by potassium and sodium cations at the hydration stage of products of hydrargillite thermal activation during synthesis allowed obtaining adsorbents-desiccants with high values of static (more than 20 g/100g) and dynamic capacitance (more than 5.0 g/cm³) by water vapors.

The paper presents the research results of physicochemical characteristics, adsorption kinetics and value of adsorption capacity with respect to water vapors of the composite adsorbent "CaCl₂ – aluminum oxide". Sorbent synthesized by centrifugal thermal activation of hydrargillite and its subsequent hydration in mild conditions was used as a carrier. It was shown that, in the studied range of change in the CaCl₂ content of the adsorbent (8.6-15.5% mass.), a sample containing 13.8% mass. of CaCl₂ was the most promising when used as a desiccant. This sample was characterized by static capacitance that was higher than 20 g/100 g, by quite high dynamic capacitance of 5.8 g/100 cm³ and good mechanical strength of 4.9 MPa.

La_2-xMg_xTiO_5-δ samples with different content of Mg and La were synthesized by the precipitation from a mixed solution of Mg(NO₃)₂ and La(NO₃)₃ in the presence of TiO₂ suspension. The samples were characterized using X-ray diffractometry, mercury porosimetry, and BET techniques. Specific surface area of the samples ranges from 0.1 to 4.17 m²/g, and pore volume, from 0.005 to 0.023 cm³/g. Activity and selectivity of the samples in the oxidative condensation of methane (OCM) were measured using a fixed catalyst bed flow quartz reactor. It was demonstrated that samples with x ≤ 0.6 showed the highest activity toward OCM reaction. This can be explained by a high content of the main active phase (La,Mg)₂TiO_5-δ with the layered perovskite structure and a sufficient specific surface area.

The paper presents the results of studies of rheological properties of the initial viscous solutions of polyvinyl alcohol and 'oil-in-water' (O/W) emulsions. It is found that aqueous solutions of polymer and polymer-based colloidal systems have typical non-Newtonian properties. After the freeze-thaw cycle, the viscous liquid systems pass into a solid state of aggregation to form multicomponent cryogels with rubber-like structure. The elastic properties of two-component cryogels consisting of polyvinyl alcohol and water only, three-component compositions formed on the basis of an 'aqueous PVA solution-mineral oil' emulsion, and cryogels containing loose dispersed fillers are investigated. The physicochemical properties of the obtained elastic samples are studied. The prospects of application of cryogels for the oil producing well and road construction are outlined. A comparative analysis of physicomechanical properties of cryogels depending on the nature of the filler is carried out. In order to simulate the real conditions of oil field construction in the permafrost zone, samples of cryogels with solid dispersed fillers pre-wetted with oil are prepared and their mechanical and hydrophobic properties are investigated. Hydrophobic properties of cryogels make it possible to use them as waterproofing layer (membrane) in the construction of the asphalt pavement and insulation of the bottoms and walls of hydraulic structures. Cryogels can be recommended for use as polymer 'pigs' for removal of undesirable deposits in the pipeline during its cleaning or for pipeline pressure testing. In this case, 'batching pigs' are introduced to the boundary between hydrocarbon liquid and water.

The authors obtained spherical biomaterials of TiO₂ – SiO₂ – P₂O₅/MgO composition by sol-gel method. TOKEM-200, a weakly acid porous cation exchanger based on acryl-divinylbenzene was used as organic matrices. The cation exchangers were saturated with Mg²+ ions. Sol based on titanium butoxide, tetraethoxysilane and phosphoric acid was deposited on them. The temperature condition for producing spherical materials TiO₂–SiO₂– P₂O₅ / MgO were proposed. To obtain a spherical material, the treated cation exchangers were subjected to stepwise heat treatment in the temperature range from 60 to 600 °C. To study the biologically active properties of the material, the samples were immersed in simulation body fluid (SBF).

Silica fume is a processing waste of ferroalloy factories. The application of silica fume instead of cement allows producing high strength concrete, as well as concrete types of the middle and low classes providing a saving in cement of up to 50 %. The authors have developed a technology for preparing a concrete mixture for reinforced concrete structures with silica fume. The technology is simple and does not require additional expensive equipment having low power intensity. The technological parameters have been investigated. They are related to slump, maturing conditions during steam curing and monolithic casting. The economic efficiency of applying concrete mixtures containing silica fume has been determined.

The development of new methods of physicochemical analysis opens vast opportunities for studying the kinetics and mechanisms of the structure formation in cement systems. A study of the structure formation and cement hardening processes will allow widening a range of methods of their non-destructive testing and developing production techniques for advanced composite materials. The X-ray microtomography system is used to analyze the formation of alternating dark and bright concentric rings both on the surface and in the bulk of the specimens. It is supposed that the formation of concentric rings is caused by the generation of acoustic vibrations in the cement-water system at early stages of the structure formation.

The article presents a technology for producing foam concrete using activated quartz waste. The waste is an ultrafine filler in the cement stone that builds pore-forming walls and generates a structure with minimal pores (with a diameter down to 50 microns) and walls with similar cross-section. The average density of such foam concrete is 500 kg/m³ and the total porosity equals 69-76%. The specimens demonstrate increased strength and reduced thermal conductivity. The use of the ultrafine filler in foam concrete reduces cement consumption by 10%, increases the density of the cement stone by 4%, augments the strength of the foam concrete by 10% and reduces its thermal conductivity by 8%. The results of the tests approve increased operational, physical and mechanical properties of such foam concrete.

The paper scrutinizes the application of an ultradispersed filler from activated quartz waste as a modifier of cement stone and resulting physicomechanical characteristics of the latter. The deliverables justify the addition of the ultradispersed filler to cement stone in production of cement concrete. The physicomechanical characteristics of quartz-cement stone after dry and wet activation are given. Goal: the goal of the present work is to study the physicomechanical properties of the cement stone modified by ultradispersed quartz filler. Methodology: mechanical milling is used to get ultrafine particles. Research results: the research establishes that the effective ratio of ultradispersed activated quartz to cement is 30:70. The application of the ultrafine filler based on activated quartz waste allows increasing the density by 7%, strength by 35% and lowering the heat conductivity by 16%. Practical use of results: the work proposes a method for producing cement stone with augmented physicomechanical properties using quartz waste in the amount of 30% in total cement volume. Value: the work scientifically justifies the possibility to produce cement stone under hydraulic activation with denser structure with the major volumetric fraction of the filler represented by quartz waste particles with dimensions less than 20 μm.

The paper shows the promising use of sea sand for additive technologies in construction. The use of sea sand reduces the setting time of the concrete mix and increases the initial strength compared to conventional quarry construction sand. A comparative analysis of the characteristics of sea and quarry sands was performed. It has been experimentally proven that the use of sea sand instead of quarry sand in fine-grained concrete mix leads to a decrease in the setting time of the fresh mix and an increase in the strength of concrete samples. The flexural strength and compressive strength of samples containing sea sand at the age of 28 days increases by 35.7% and 16.7%, respectively, comparing to samples containing quarry sand.

The paper considers alternative methods of activation of cement systems based on the use of internal properties of cement. Their peculiarity is the use of activated cement and changing the sequence of mixing of cement mortar. Mixing of the main volume of Portland cement with cement slurry and its prior curing for 15 minutes allowed increasing the strength characteristics of hardened cement paste. As shown by experimental studies, the strength of the samples increases by 10–30% depending on the method of preparation and curing time of the cement slurry. Further experiments will be aimed at researching "activated cement–activated water" system.

The paper presents the study on the effect of heating wire pitch on the strength of concrete in cast-in-place thin-walled wall structure when heated with the use of heating wire in the mold made of 40 mm thick wood depending on the wind speed and outdoor air temperature using ELCUT software. The conclusions include recommendations on cold weather concreting of a cast-in-place reinforced concrete wall with the surface modulus S_m = 10.

Article represents recommendations on decrease in heat losses through heat-conducting inclusions of sandwich panels. Recommendations are based on the analysis of calculations by a finite element method in software package Elcut and thermal imaging. The purpose of this study is to increase the thermal protection of buildings built with sandwich panels for the South Siberia conditions. The way of decrease in the factor of cold bridges is studied by adding thermal insulation of panel node connections. The authors analyzed constructive joints: roof parapet, roof cornice and junction of wall panels.

The present paper investigates a cement based foam concrete with glyoxal-containing additives which are introduced into the mixture in different ways. The relevance of the given study is conditioned by the necessity to provide the required quality parameters of mixture for transportation and laying the formwork, as well as providing strength and physical characteristics of wall structures for housing construction. Four ways of introducing additives into the foam concrete mixture have been proposed: spraying with 40% glyoxal aqueous solution; joint grinding of sand with crystalline glyoxal in the amount of 0.01% by weight of cement; introduction of crystalline glyoxal into the foam concrete mixture; introduction of a 40% aqueous solution of glyoxal to the foam concrete mixture. The study was conducted in the Laboratory of Tomsk State University of Architecture and Building which is accredited in accordance with the national standards requirements. Glyoxal-containing additives applied within the technology of cement foam concrete of natural hardening contributes to ensuring increased aggregative stability of mixtures and compressive strength at the age of 28 days. The elaborated composition and technology of foam concrete production with glyoxal-containing additives is intended for use in the walls structures as well in monolithic construction as in pre-cast production.

The paper presents the results of predictive modelling of the mechanism of Portland cement curing using the VCCTL tool. The curing is studied at the water-cement (W/C) ratio of 0.30 and 0.35, during 28 days at room temperature. It is shown that the hydration degree correlates with the heat generation and the accumulation rate of hydration products. At W/C=0.30, the content of clinker phases and hydration products is higher than at W/C=0.35, but the rate of the indicated processes is almost similar. The growth in the water-cement ratio reduces the pore space filled with free moisture as well as the moduli of rupture. The correlation is detected between the Portland cement strength and Young's modulus in the form of quadratic and cubic polynomials. These dependencies are in good agreement with the literature data and testify to the suitability of the VCCTL microstructural model of Portland cement curing.

This paper is devoted to study of the laws of metals deformation behavior determined by carrying out standardized uniaxial tensile tests. The analysis of deformability of materials was carried out. The metals vary in yield limit from 40 to 1050 MPa and in ultimate strength from 460 to 1240 MPa. The ratio of the deformation work of uniform plastic deformation (from the yield point to the ultimate strength of materials) to the volume of the material was determined to assess the mechanical deformability. An inverse relationship between uniform deformation work and ratio of yield limit to ultimate strength was established. It was also found that the normalized specific work of deformation linearly increases with strength. The deformability criterion can be considered as the universal criterion for ferrous and non-ferrous metals and its magnitude can be estimated from known quantity of the ultimate strength. In practice, the numerical values of compliance criterion can be used to predict the behavior of materials with different strength under mechanical perturbations in the course of operation and machining (metal forming and cutting).

This paper considers an assignment of the high-resolution Fourier spectra of ¹⁵NHD₂ molecule in the region of ν₆ band. The analysis is based on the combination differences method. As a result of the analysis, the energy structure of inversion-vibrational states (v₆=1, s) and (v₆=1, a) was obtained. More than 550 vibration-rotation transitions were found and values of about 140 upper vibrational energy levels were determined in total.

The results of investigation of the gas-sensitive properties of sensors based on the tin dioxide thin films with combined additives of gold and nickel obtained by the DC - magnetron sputtering are presented. The investigated sensors are characterized by a high response to low concentrations of NO₂ of 0.45 – 10.23 ppm at temperatures of 50 – 150 °C with response time of 10 s. The sensitivity of sensors to hydrogen appears at the temperature of 250 °C. The hydrogen sensors are characterized by high reproducibility of the measurement results. The obtained results are explained by the synergistic effect of gold and nickel additives, as well as the ability of the Ni to prevent the interaction of hydrogen with lattice oxygen atoms in the subsurface part of tin dioxide.

In the present study, a microstructural investigation of wire-feed EBAM-manufactured nickel-based and titanium-based alloys were conducted by producing single wall sample with 16 and 19 vertical layers, respectively. It was shown that in obtained material microstructural and elemental gradient presents. The results of the research show that dendrites and grains grow epitaxial in the direction of temperature gradient. Non-directional dissipation of heat on the edge of the sample leads to formation of equiaxed structure. Chosen parameters allow to produce low-defective samples by EBAM technology.

This paper is devoted to obtaining the multimaterials using the electron-beam wire-feed additive manufacturing technology. The sample of titanium alloy Ti-6Al-4V and stainless steel 321 composition was obtained. It was found that steel and Ti-alloy form a transitional intermediate layer between themselves. The Ti-alloy layer does not undergo major changes, while the layer of stainless steel undergoes significant cracking.

This paper presents a research data on investigation of physical-mechanical properties of the surface of NiTi shape memory alloy after low-energy high-current pulsed electron beam (LEHCPEB) treatment in surface melting mode. Investigation of physical-mechanical and functional properties (Young's modulus E_IT, dynamic hardness H_IT, plasticity characteristic δ_H, and parameter of shape recovery ratio η) was held by method of instrumented nanoindentation test. Our data suggest that after LEHCPEB treatment physical-mechanical properties of the surface layers of ~500 nm thickness change in depth from the surface without critical influence to the pseudoelastic properties of NiTi alloy.

Based on the analysis of the elastic-stressed state of partial disclinations of nanodipoles the rate of the quasi-viscous deformation mode in nanocrystalline structures is estimated. It's shown that velocity of movement of point defects (V) and nanodipole propagation $(\dot{L})$ within the quasi-viscous deformation mechanism, depending on the activation energy of the migration of point defects (vacancies, interstitial atoms) and deformation temperature, can reach high values close to the speed of sound in metals.

Disclination models of grain boundaries in crystals are considered. The features of the spatial distribution of the configuration stress fields depending on number of disclinations and magnitude of the common Frank's vector are described. The estimate of the energy of the configurations based on the calculations in a wide range of values of the bending-torsion tensor 0.2...1.8 degrees per nanometer was obtained. It was shown that the energy of the equidistant model is higher than the energy of the other two with irregular distribution of disclinations.

Investigation of influence of mechanical activation duration in high-energy planetary ball mill on morphology, microstructure parameters and microhardness of 3Ni – Al powder system was conducted. Main stages of transformation of microstructure and mechanical properties are revealed.

Investigation results of surface oxide scale features during the oxidation of V–Cr– Ta–Zr alloy in air are presented. Intensive oxidation processes in time interval under study lead to an increase in the scale thickness. Oxide scale structure is characterized by open porosity formed as a result of sticking together of small flakes of plate-shaped oxides (V₂O₅).

Investigation results of microstructure influence on oxidation coefficient during chemical-heat treatment of V–Cr–W–Zr alloy are presented. It is shown that the formation of a high defect structural state in the alloy leads to a twofold increase in the oxidation coefficient and a significant increase in the oxygen concentration. The maximum effects of the microstructure on the oxidation processes are detected at short treatment times.

The effect of stabilizing annealing temperature on the features of microstructure and microhardness of V–Cr–Ta–Zr alloy after thermomechanical treatment by regime II was studied. Main stages of relaxation processes are revealed. Characteristic microstructure parameters and microhardness values are determined for each relaxation stage.

Sol-gel method from zinc acetate in water was employed to synthesize nano-sized zinc oxide. The structural features of the ZnO obtained samples, their spectral features of luminescence and photoconductivity were studied. The influence of the treatment temperature on the luminescence and photoconductivity of nano-sized zinc oxide was studied. The type and energy position of the intrinsic defects involved in the luminescence and photoconductivity processes were determined.

A systematic study of photoluminescence transitions of samarium ion (Sm³⁺) incorporated in titanium dioxide (TiO₂) powder with anatase structure has been performed. Perceptible changes of luminescence under direct excitation as compared with indirect excitation of Sm³⁺ in titanium dioxide (TiO₂:Sm³⁺) have been detected. Measurements of photoluminescence excitation spectra for all detected radiative transition of Sm³⁺ were accomplished. The values of asymmetry ratio were calculated for different excitation wavelengths. The dependence of luminescent intensity on Sm³⁺ doping concentration in TiO₂ host was studied under direct and indirect excitation. Thus, evidences of the existence of the several Sm³⁺ sites in anatase TiO₂ have been presented in this work.

The paper contains the results of hydrometallurgical processing of technogenic pyrite raw materials. The method is based on selective extraction of gold and silver from ore by solution, which contains sodium sulfite and sodium sulfate. The most promising results were obtained utilizing solution with sodium sulfite and sodium sulfate concentration of 25 g/L and leaching time – 1 hour. Under these conditions, the extraction of gold was 67%. The use of sodium sulphate and sodium sulfite allows to extract gold and partially silver from refractory sulfide ores.

It is present electron optics optimization for terahertz radiation generation by a sequence of short electron bunches passing through the dielectric loaded waveguide. In this method the superposition of individual bunch wakefields is used to selectively excite high frequency TM0n modes in a slow-wave structure. The main problem of this scheme is the transverse beam instability that limits the length of THz radiation wave packet. The main goal of this paper is a new parameter optimization algorithm for the FODO focusing system. The numerical modelling of the beam dynamics was performed in the original code "Dielectric waveguide" which utilizes analytic expression of the Green's function for the dielectric loaded waveguides with cylindrical and rectangular geometries.

Wakefield acceleration of electron bunches is effective method developed for linear accelerator techniques. The main problem of this method is transverse beam dynamics which limits the propagation length of bunch. This work is dedicated to beam dynamics in dielectric waveguide with rectangular geometry. This type of waveguide has complex mode composition including LSM and LSE modes. The main purpose is a study of modes influence in rectangular dielectric waveguide on beam dynamics with different types of dismission of driver from waveguide's axis. It is shown that the LSM asymmetric modes make a major contribution to wakefield and transverse dynamics.

In this work porous microparticles of calcium carbonate were synthesized with bovine serum albumin - fluorescein isothiocyanate conjugate (BSA-FITC) and dexamethasone, and then used for encapsulation in polymer microcapsules by means of layer-by-layer assembly (LbL). The properties of the obtained microcapsules were characterized by scanning electron microscopy, dynamic light scattering, infrared-, ultraviolet- and visible spectroscopy. According to the performed DLS measurements, an average hydrodynamic diameter ranged from 4 to 8 µm and zeta-potential for all types of capsules was determined as -18 and -21 mV. BSA-FITC was encapsulated using this approach yielded a loading efficiency of 49 % protein. This value calculated for dexamethasone was of 38%. The microcapsules filled with an encapsulated drug may find applications in the field of biotechnology, biochemistry, and medicine.

The temperature-strain rate domain of the Portevin-Le Chatelier (PLC) effect has been determined for three ultrafine grained aluminum alloys: Al-3Mg (A1), Al-4,57Mg-0,35Mn-0,2Sc-0,09Zr (A2) and Al-5,4Mg-0,52Mn-0,1Zr (A3) (wt.%). The apparent activation energy of the serrated yielding was estimated. It was found that the presence of dispersed particles leads to a decrease in the activation energy and the temperature–strain rate domain of the PLC effect becomes narrower.

This paper is devoted to fabrication of Ti₃SiC₂-based ceramic materials from preceramic paper using spark plasma sintering (SPS) method. The synthesis temperature and pressure were 1373-1473 K and 30 MPa, respectively. The phase composition, microstructure and elemental composition were analysed using X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. The effect of temperature on the sintering process as well as on the phase and microstructure of the sintered materials was investigated.

This paper describes the effect of surface modification by high-intensity Ti-ion implantation on the high-temperature oxidation resistance of E110 zirconium alloy. The oxidation tests were performed in air at 873 K for 10 h and in water steam at 1373 K for 10 min. The microstructure, phase composition and depth distribution of elements were analysed using scanning electron microscopy, X-ray diffraction and glow-discharge optical emission spectroscopy, respectively.

Silumin, aluminum with silicon alloy, is a promising material used for the manufacture of medium-loaded machine parts and mechanisms. High brittleness is one of the main drawbacks of hypereutectic silumin. Modification of a hypereutectic silumin (18–20 wt.% Si) was carried out by irradiating the samples with an intense pulsed electron beam. It was established that irradiation of cast hypoeutectic silumin by an electron beam leads to a significant reduction in the number of micropores, forming a high-speed cellular crystallization structure with a cell size of (0.4-0.6) μm. An irradiation mode allowing to increase the silumin surface layer hardness by more than 4 times, wear resistance - by 1.2 times, to increase ductility by 1.2 times in relation to the initial material was detected (35 J / cm²; 200 μs, 20 imp. 0.3 s⁻¹).

Herein, electrospun biodegradable scaffolds based on polycaprolactone (PCL), poly(3-hydroxybutyrate) (PHB) and polyaniline (PANi) polymers were fabricated. A calcium-phosphate (CaP) coating was deposited on the surface of the scaffolds via an improved soaking process. Influence of the deposition cycles and ethanol concentration in the solution on the relative increase of the scaffolds weight and water contact angle (WCA) are determined. The characterization of the molecular and crystal structure confirmed the formation of CaP phase. Importantly, WCA results showed that the pristine scaffolds have the hydrophobic surface, while the deposition of CaP coating onto scaffolds allows to significantly improve the surface wetting behavior, and infiltration of the water droplets into the CaP-coated scaffolds was observed. Thus, the fabricated hybrid biodegradable piezoelectric scaffolds can be utilized for regenerative medicine.

The article presents the results of experimental studies on the choice of the optimal technological parameters (the initial moisture of the soil-cement mixture, pressing force, amount of cement) for the preparation of samples of soil-concrete by semi-dry pressing. Research has shown that the predicted strength of the soil-concrete can be obtained not only by varying the amount of Portland cement injected, but also by selecting the pressing force and the initial moisture of the initial mixture. The obtained experimental data allow predicting the construction and operational properties of soil-concretes materials from clay raw materials of a specific field, to clarify the methods of manufacture and the area of their application (foundations of airfields, roads and engineering structures, building products and structures).

The light induced current in doped lithium niobate crystals with two electrodes of different metals (sandwich system) includes the photovoltaic and the thermoinduced effects. The anomalous coordinate dependences of the light response are revealed and investigated experimentally.

The theoretical analysis of the dynamic holograms efficiency in the nonideal nanoparticle gas is carried out. The electrostrictive mechanism of optical nonlinearity of the medium is due to the forces operating on the particles of the dispersed phase in gradient light field. The recording of the dynamic hologram is significantly non-linear process at high intensities of radiation. The amplitude of phase grating depends exponentially versus intensity but it saturates at the high filling factor due to the repulsion effect.

The purpose of this study is to investigate the possibility of forming an eyeball musculoskeletal stump using a Ni-Ti implant in vivo. Studies were performed on 18 Wistar rats. The animals were enucleated one of eyes. After the enucleation the musculoskeletal stump using Ni-Ti implant was formed. Ni-Ti implant was made from a thread of porous Ni-Ti (TN-10) with a thickness of 100 μm. Before implantation the Ni-Ti implant was sterilized by ethylene oxide. Results showed that the Ni-Ti implant surface was uniform and had not visible defects. The Ni-Ti implant surface was a hydrophobic with the mean value of θ = 93.5º ± 1.4. The Ni-Ti implant in the eye orbit was mobile. The Ni-Ti implantation into the eye orbit contributed the connective tissue with blood vessels formation and insignificant leucocytes infiltration (macrophages and lymphocytes infiltration). The study showed the possibility of forming an eyeball musculoskeletal stump using a Ni-Ti implant.

The purpose of this research is the study of the influence of thin polylactic acid films implantation on the corneal morphology in vivo experiment. Studies were performed on 8 pubescent female Sylvilagus bachmani rabbits. Polylactic acid films were implanted into the anterior chamber of one animal eye. The feedstock for the films was obtained by dissolving polylactic acid in the chloroform. Before the implantation PLA films were sterilized. The overall duration of the in vivo experiment comprised 21 days. Such methods as visual check, photographic registration, non-contact ocular tonometry and optical coherent tomography of cornea were also used in course of the experiment. Sampling was performed on day 21 after the start of the experiment for morphology studying. Results showed that the implantation of the PLA films into the anterior chamber of eye does not induce an inflammatory reaction and does not increase an intraocular pressure. The study showed the possibility of PLA films using as a corneal implant.

The paper considers the protection of critical electronic equipment from an ultrashort pulse (USP) by means of modal filtering technology. Decomposition of the USP in a reflection symmetric meander line consisting of four cascaded half-turns is investigated for the first time. Quasi-static simulation of two half-turn connection diagrams has been performed. The output of the circuits shows the presence of negative polarity pulses, as well as additional pulses with time delay values non-multiple of per-unit-length time delays. It has been revealed that these values are linear combinations (arithmetic means) of per-unit-length time delays of the line modes.

This work presents the theoretical model of holographic formation of the diffraction optical element (DOE) in photopolymer material (PPM). DOE allows transforming Gaussian light fields to Bessel-like. Self-diffraction of writing light beams at low contrasts is taken into account. It is experimentally shown that influence of effect of self-diffraction in areas of low contrast leads to amplification of level of side's maxima of diffracted light beam.

The article presents the results of using a multi-aperture extraction system in the source of a ribbon electron beam. The optimal size of the holes in the anode and extractor, as well as the distance between the anode and the extractor at which the beam losses are minimal, are investigated.

The article presents the results of electron beam sintering of alumina ceramic in the so-called forevacuum pressure range (5-20 Pa). Ceramic was irradiated by a focused electron beam generated by the forevacuum plasma electron source. Various modes of irradiation are considered without and with scanning of the electron on the ceramic surface. It is shown that using electron beam scanning increases the homogeneity of the sintered material. The modes of irradiation allowing to obtain dense ceramics with a homogeneous density distribution over its volume are given.

The paper describes the implementation of a method for modeling threats to information security using the methodology of IDEF0 functional modeling to solve problems of formalization of specific threat models. The formulation of the method for modeling threats to information security accounts for various media of information transmission and its carriers. In addition, a process approach to information handling is used.

This article is devoted to studying the possibility of improving the quality of the identification of notes in vocal performance. In the present work, the authors described the transition of the program complex to a distributed functioning model. At this stage, this allowed organizing the storage of results for students and the introduction of an assessment mode for teachers. A study was conducted to improve the quality of note recognition through the use of other algorithms. During the tests, it was determined that the presence of vibrato in singing makes the greatest contribution to the number of unidentified notes. In view of the findings scheduled implementation in a program complex the paalgorithm which is responsible for determining the quality of vibrato in singing. The purpose of this modification is to get rid of novice singers from problems in singing, such as tremor.

There is the relevant issue of cleaning the ducts walls from dust deposits on industrial plants, workshops and production lines equipped with exhaust ventilation systems. Improving the efficiency of the process of cleaning air ducts from dust depends on the long-range of compact jets. The mathematical model is based on the classical solution of the "submerged jet" problem propagating in a stationary medium. The use of this model made it possible with sufficient accuracy to estimate the parameters of the range of compact jets when operating aspiration systems. Studies have shown that the presented model can be used to analyze the state of the pipelines of the suction networks and dust collection plants.

The process of deformation of aluminum samples under dynamic groove pressing for a dynamic loading scheme is studied numerically in a two-dimensional formulation. Areas of intense plastic deformation of the sample are revealed. Localization of plastic deformations is similar for the static loading pattern. The results of damage accumulation in the material are given. The finite element results are in good agreement with the experimentally obtained results in the field of strain rates considered in this study.

In this paper, we propose an efficient modified multistep method for direct solution of boundary value problems (BVPs) using multistep collocation approach. The continuous form was evaluated at grid and off-grid points to obtain the multiple finite difference schemes. The basic properties, such as order and error constants, zero stability and convergence analysis of the proposed methods were investigated. Numerical experiment were performed to show the efficiency of the method and the results were compared with the existing methods in the literature.

In this paper the mathematical modeling of the interaction of a single supersonic jet with a flat obstacle in a rarefied atmosphere and Mach numbers at the nozzle exit 4 are considered. Mathematical modeling using free OpenFOAM-Extended software and authors' program are done. Comparison of calculation methods: PISO algorithm, Rusanov and Godunov schemes was carried out. The comparison results show a qualitative coincidence in the shape of the supersonic jet, wall jet and the system of shock waves. But the numerical results are quantitatively different, pressure on flat obstacle varied within 7-14 kPa. The peak of pressure is on the periphery for results of sonicFoam and dbnsFoam. For all solvers average pressure at axis of jet is 8 kPa and the first barrel of wall jet is started about at 0.4 meter from axis was obtained.

The paper presents a method for calculating the local and integral characteristics of the flow in the axisymmetric gas-dynamic paths of solid propellant rocket motors, taking into account the combustion of a charge of solid fuel. The numerical method of calculation is based on the use of the Godunov scheme, formulated for moving computational grids. The speed of movement of the combustion surface is defined locally on the edge of each calculation boundary cell. This approach allows us to take into account the uneven distribution of the pressure of the combustion products in the free volume of the combustion chamber. In test calculations, the power law of burning rate is used. Calculations of the gas flow in the solid propellant combustion chamber with cylindrical charge of solid fuel are carried out. Unsteady pressure curve in the combustion chamber is obtained. The method allows to determine all integral characteristics of the developed solid propellant rocket motors as a function of the engine running time.

This article presents the results of mathematical modeling of the interaction of a single supersonic jet with a wedge barrier. The angles of the wedge were 0, 5, and 10 degrees. The distance from the nozzle to the barrier was 0.5 meters. The parameters of the gas of hydrazine combustion products at the nozzle inlet varied. Mach number at the nozzle exit was 4 and 5. It was found that the wedge angle of the barrier slightly affects the shape of the jet, the shape of the wall jets and the pressure along the barrier at an ambient pressure of 650 Pa and a temperature of 250 K. With an increase in the barrier angle, the pressure on the jet axis decreases and the first barrel of the wall jet is displaced.

The article is devoted to the problem of the unique solvability of initial boundary value problems for partial differential equations. These initial boundary value problems are dissipative dynamic mathematical models from the field of linear elasticity. The considered equations are not resolved with respect to the highest time derivative. Therefore, these equations are referred to the so-called Sobolev type partial differential equations. The research of initial boundary value problems is carried out from general position in the form of the complete second order differential equation in abstract spaces. The theory of the distributions with values in Banach spaces and the concept of a fundamental solution of differential operator are used. Theorems of existence and uniqueness of the solutions of considered initial boundary value problems in the class of functions of finite smoothness with respect to time are proved. These solutions are obtained as an functional series of the Kummer confluent hypergeometric function.