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Objective. Comprehensive studies of ancient concretes have established the presence in them of zeolite-like minerals, which are analogues of naturally occurring compounds containing alkalis. The work presents development of research aimed at obtaining compounds similar to existing minerals of the earth's crust, and encourages researchers to develop alkali binder systems to use the best results during repair and restoration work of historical architectural objects. During the experiment, such important properties for repair compositions as density, ductility, adhesion, viability and strength were studied.Method. The studies were carried out in accordance with regulatory documents GOST 12730.3–2020 Concrete. Methods for determining water absorption; GOST 5802–86 Construction mortars. Test methods; GOST 31356–2013 Dry building mixtures based on cement binder. Test methods.Result. The results obtained correspond in their technical characteristics to products based on Portland cement, the mortar grades were achieved in terms of strength M75–150, in terms of mobility Pk1 and Pk2, viability sufficient for carrying out repair and plastering work 33 minutes – 1.5 hours, high adhesive strength 0.62–0.72 MPa.Conclusion. The compositions of mortar mixtures will allow high-quality performance of a variety of work: repair, plastering, finishing. The stable properties of the components, strict adherence to the compositions and production technology of mixtures will make it possible in the future to synthesize nature-like and durable minerals in the structure of a high-quality and durable material.

Milk powder is a commercial product of mass consumption. Its popularity means a variety of quality and production requirements. New methods of skimmed milk powder production are strategically important for the food industry in Russia and worldwide. Russia is currently experiencing a shortage of low-heat milk powder import. The research featured the effect of thermal treatment and pasteurization mode on the protein profile and microbiological parameters of skimmed milk powder. The research objective was to establish the thermal variables for low-heat milk powder. The study involved raw milk, skimmed milk produced under different heat treatment conditions, and skimmed milk powder obtained from this milk. The authors used standard analytical methods to define the protein profile, as well as the microbiological and physicochemical parameters. A set of experiments made it possible to classify the heat treatment of skimmed milk powder produced under various milk pasteurization modes, as well as to establish its biochemical and microbiological parameters. The optimal mode for low-heat milk powder was a combination of thermal treatment (60 ± 2°C for 10 s followed by cooling to 10°C for 10 h) and low-temperature pasteurization (72 ± 2°C for 15 s). The powder obtained met the Technical Regulations of Customs Union TR CU 033/2013 and State Standard 33629-2015. A lower thermal load maintains the microbiological safety of milk powder while preserving its quality. In this study, the optimal thermal treatment and pasteurization mode yielded milk powder of low-heat category, thus preserving the native protein and microbiological safety. As a result, the low-heat milk powder acquired some high-quality functional and consumer properties.

The study of the acoustic properties of maraging steels operated under various energy force and temperature actions is a critical task, since it is the method of acoustic structuroscopy that provides the most reliable connection with the structure, stress-strain state and mechanical properties of steels. The paper is devoted to research of the acoustic properties of the 15-5 PH maraging steel samples under various types of heat treatment under the conditions of mechanical tensile and cyclic loads. Samples of the 15-5 PH maraging steel were studied in three structural states: solid solution annealing and subsequent aging at 470 and 565 °C; during tensile tests; during cyclic tension-compression loading. The research used a unique scientific installation “Information-measuring complex for investigation of acoustic properties of materials and products”. It implements the acoustic mirror-shadow multiple reflections method using electromagnetic-acoustic and piezoelectric transducers based on polyvinylidene fluoride film to excite and receive waves and allows determining the velocity of wave propagation with an error of no more than 2 m/s. The acoustic (wave velocity, elastic moduli, electromagnetic-acoustical (EMA) transformation coefficients, acoustic anisotropy coefficients, acoustoelastic coupling coefficients) and electromagnetic (coercive force and electrical conductivity) characteristics of the samples were examined. The samples were studied in the initial state (before loading); stepwise in the process of tensile loads and subsequent unloading; after tensile tests; during cyclic tension-compression loading. It was revealed that the following acoustic parameters of 15-5 PH steel samples are the greatest structural sensitivity to mechanical tensile load and cyclic loading: transverse wave velocity, Poisson’s ratio, double EMA-transformation coefficient, and acoustic anisotropy coefficient.

Additive 3D printing technologies dynamically developing at a rapid pace are used in progressive industries. There are several types of additive technologies based on different physical principles: selective laser melting (SLM), electron beam melting (EBM), fused deposition modelling (FDM), lamination object manufacturing (LOM), etc. They are all united by one technological principle — the production of items through layer-by-layer construction. Similar to traditional shaping methods, each type of additive technology has advantages and disadvantages. The principal materials traditionally used for functional products of various purposes are metals and alloys. Two main technologies for fabrication of metal products are currently well developed worldwide: SLM and EBM. Despite the high accuracy and decent quality of the products obtained by means of these technologies, they have several disadvantages, including the high cost of both the technological equipment and the raw materials used.

Inhomogeneities in the near-surface region of diffusion-doped silicon with manganese atoms were studied using the local photo-EMF method and photovoltage and photoconductivity signals were detected. It has been established that the inhomogeneous region is located at a depth of 3÷35 μm from the surface of the crystal. The magnitude of photo-EMF in these layers does not change monotonically from point to point. It was revealed that the photo-EMF spectra depend on the wavelength of the irradiated light, while the shape of the areas and their shift are related to the penetration depth of laser radiation. The photo-EMF signal increases to a depth of ~25 µm from the surface, then saturates and from ~30 µm smoothly decreases and completely disappears at a depth of ~40 µm. The magnitude of the internal electric field was determined using the Tauc method. A model of the structure of the near-surface region of diffusion-doped silicon with manganese is proposed.

In this research, a comprehensive study of the effect of doping silicon with gold on the optical properties and morphology of silicon layers was carried out. For this purpose, the methods of Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used. The results of the study showed that the transition from original silicon to gold-doped silicon leads to significant changes in the optical properties and morphology of the layers. Raman spectra showed characteristic peaks in the regions of 144, 304, 402, 464, 522, 948 and 973 cm–1, associated with the violation of long-range order of the crystal lattice and the interaction of gold with silicon. The intensity and position of the peaks in the spectra allowed us to draw conclusions about structural changes, including a decrease in crystallinity and the formation of amorphous and nanocrystalline structures in the samples after treatment at 1373 K. New peaks in the Raman spectra associated with Au-Au stretching and the formation of new bonds Si-Au, confirm the processes in silicon layers when alloyed with gold. SEM studies provided information on the structure, chemical composition and arrangement of n-Si-Au and p-Si-Au samples. The spherical arrangement of gold atoms on the surface of single-crystalline silicon was experimentally established, which indicates the diffusion of gold and the formation of gold silicate, which introduces a positive charge to the interface. Morphological changes included an increase in the number of agglomerates with nanocrystals smaller than 7–9 nm and an increase in the transparency of the layer. These results indicate the possibility of improving the photosensitivity of heterostructures with a Si–Au composite layer due to the quantum-size and plasmonic effects of inclusions containing silicon and gold nanoparticles.

In this work, the structural and optical characteristics of silicon (n-Si) samples and its compositions with dysprosium (n-Si-Dy) were analyzed using Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy methods. Characteristic peaks in the FTIR spectra such as 640 cm-1 (Si-H mode) and 1615 cm-1 (perpendicular stretching mode) were identified, indicating the structural features of the material. The appearance of additional peaks in the n-Si-Dy spectra at 516.71 cm-1 and 805 cm-1 indicates the influence of dysprosium on the structure and defectiveness of the material. Examination of the frequency range (1950–2250 cm-1) further confirms local vibration modes associated with defects and interactions with dysprosium. Peaks associated with Dy-Dy stretching, as well as interaction with silicon, were found at 2110 cm-1 and 2124 cm-1. Analysis of Raman spectra indicates the formation of silicon nanocrystals during annealing, which is confirmed by XRD results. The results obtained provide important insight into the effect of dysprosium on the structure and properties of silicon materials, which could potentially find application in optoelectronics and materials science.

The study of thin-film nanocomposites, including crystalline and amorphous silicon nanoparticles embedded in silicon oxide layers, is a key direction in the field of materials for optoelectronics. This study explored the interest in such composites, including erbium silicide (ErSi2-x), in the context of their applications in non-volatile memory and photovoltaic devices. Particular attention was paid to the structure and properties of such materials, including the analysis of defects in erbium-doped silicon. The results of the study, based on Raman spectroscopy and X-ray phase analysis, made it possible to identify the characteristics of the composition and structure of the studied samples. The identified data confirmed the presence of crystalline phases of Si and Er in the p-Si-Er composite, and also showed the substitution of Er in the p-Si/SiO2 structure. Additionally, X-ray microanalysis data confirmed the presence of Si, O and Er in the expected concentrations in the composite film. Further research showed that the introduction of erbium atoms onto the silicon surface leads to minor changes in some signals and the appearance of new vibrations in the Raman spectra of the samples. The decrease in the intensity of the peaks belonging to silicon is associated with the weakening and breaking of some bonds in the structure of the silicon crystal lattice and due to the formation of new bonds in which erbium atoms participate. Thus, the results of this study represent a significant contribution to the understanding of the properties and potential of thin film nanocomposites for applications in optoelectronics, and also enrich our knowledge of the effect of doping on the structure and properties of silicon materials.

Each crystal structure has its own phonon modes, which appear in the Raman spectrum of Raman scattering. In the case of silicon, phonon modes associated with the diamond structure of silicon can be detected. In a Raman spectrum, the position of the lines, their intensity, and the width of the lines are usually measured. Raman spectroscopy is a powerful tool for studying crystalline materials at the molecular level, and its application in the study of semiconductors and nanomaterials provides important information about their structure and properties. In this study, the spectra of two types of silicon were analyzed: n-Si and p-Si, as well as their doped analogues n-Si and p-Si. The obtained Raman imaging results demonstrated spatially varying nanocrystallinity and microcrystallinity of the samples. The n-Si and p-Si spectra indicate the appearance of a Raman band at 525 cm-1 with a shift of -5 cm-1 and +5 cm-1, respectively, relative to the position of the silicon substrate peak, indicating the presence of tensile strain in the materials. The absence of other impurity peaks indicates the high purity of the n-Si and p-Si samples. The holmium doped Si material exhibits additional peaks in the Raman spectra, which is attributed to the presence of vacancies and defects in the newly formed Si-Ho compositions. The results of the analysis of the spectra indicate the influence of doping silicon with holmium on its structure and properties, forming new bonds and defects.

Express methods for estimating the intensity of heat treatment of milk are necessary in industry and in research work. For this reason, there are many ways to measure this parameter, which are based on different physical principles, including turbidimetric methods. The Harland & Ashworth turbidimetric method has been developed for a long time, however, due to its high reliability and ease of implementation, it is still used in practice. However, this method has a drawback: it takes a long time to perform the analysis. In this regard, the aim of the work is to develop an express method for evaluating the thermal class of milk based on the principle of measuring the concentration of soluble whey proteins. The result is achieved through the use of a turbidimetric measurement method with optimized sample preparation parameters and parameters for measuring the optical density of a suspension of protein aggregates. The method is implemented as follows. The milk sample is mixed with 0.1 N acetate buffer (pH 4.6) in a ratio that allows to obtain a concentration of soluble milk whey proteins from 0.05% to 0.1%. Recommended dilution coefficients: 1:3 for samples of ultra-pasteurized milk and pasteurized milk with high heat treatment intensity; 1:7 for samples of pasteurized milk with low heat treatment intensity and 1:14 for raw milk samples. The solution is filtered on a membrane filter with a pore size of 0.45 microns. The resulting filtrate is mixed with 24% trichloroacetic acid (TCA) in a 1:1 ratio to coagulate soluble whey proteins and form protein aggregates. After holding for 5–10 minutes, the optical density of the suspension of protein aggregates is measured at a wavelength of 650 nm. The content of water-soluble whey proteins in the sample can be calculated according to the calibration curve. The developed method allows to obtain the measurement result in less time than the Harland & Ashworth turbidimetric method.

Combination steam ovens, or combi steamers, have entered all spheres of food production, including the meat industry. Their rational use requires a scientific and practical foundation. This research featured the changes in mean volume temperature and temperature gradient that occur in meat products (one-dimensional bodies with different nutrient compositions) during heat treatment in dry air and a steam-air mix. The research involved two samples of meat products with different moisture and fat contents. The chicken fillet sample had a moisture content of 74.5% and a fat content of 1.9% while the pork shoulder sample had a moisture content of 55.1% and a fat content of 29.4%. Shaped as a one-dimensional cylinder and a plate, the samples were subjected to heating at the temperature range of 160–240°C in a Unox-203G steam-convection oven (Italy). Dry air and a steam-air mix with a humidity of 80–85% served as a heating medium. The temperature was measured using thermocouples attached to a Sosna-004 meter. The research revealed some patterns in the mean volume temperature and temperature gradient. The temperature gradient involved three stages during processing in a steam-air mix and four stages when treated with dry air. The change in the mean volume temperature for the steam-air mix could be described by a power law equation; the dry air treatment was described using a linear equation. When heated in dry air, the rate of change in the temperature gradient was constant at first but started to decrease at a certain stage. The change rate in the mean volume temperature remained low for 5 min and started to increase onwards, maintaining its value until the end of the process. When heated in a steam-air mix, the change rate in the temperature gradient dropped to its minimum in 4–5 min and started to grow. The mean volume temperature demonstrated a high change rate during the first 5 min and went down. The chicken fillet with its low fat content warmed up faster by 13–26% when processed in a steam-air mix and by 9–23% when treated in dry air. The plate-shaped products needed longer heat treatment. The composition and form had no significant effect on the nature of the change in the temperature gradient and mean volume temperature. The obtained dependencies made it possible to select the optimal temperature and humidity conditions for convective frying of meat products.

The purpose of the work is to study the influence of hafnium additives on the mechanical properties and thermal stability of particles at elevated temperature during heat treatment of aluminum alloys with a high magnesium content. Two modifications of 1570 alloy were chosen for the study: without hafnium content and with its addition of 0.5 % by weight. Both alloys were subjected to homogenizing annealing at a temperature of 440 °C with different exposure modes, which ranged from 2 to 100 h. Microhardness was studied for various heat treatment modes, and the fine microstructure was studied as well using transmission microscopy. As a result, it was possible to identify that during annealing at a short exposure time (2–8 h), the alloy with the hafnium addition has higher microhardness values exceeding those of 1570 alloy by an average of 20 HV units. This is associated with the fact that in 1570 alloy with hafnium additives, during heat treatment, the number of precipitated particles increases while their average size decreases compared to the base alloy. At the same time, in 1570 alloy without hafnium content, when annealed at a temperature of 440 °C, there is no increase in microhardness. This is caused by the fact that in 1570 alloy without hafnium content, when cooled after casting, discontinuous decomposition occurs, which resulted in the fact that most of the scandium precipitates from the supersaturated solid solution in the form of dispersoids. This phenomenon is not observed in the alloy with hafnium additives, which indicates its ability to stop discontinuous decomposition during cooling the ingot after casting.

Dispersion-strengthened composite materials belong to the group of promising structural materials characterised by a diverse combination of properties. The paper considers examples of the creation and heat treatment of composite materials based on aluminium alloys strengthened by the titanium carbide dispersed phase characterised by high hardness, elastic modulus, and good melt wettability. At present, self-propagating high-temperature synthesis (SHS) is the most accessible, inexpensive and effective way to obtain them. The authors substantiate the expediency and show their successful experience of the formation in the composition of the AMg2 and AMg6 industrial alloys of a titanium carbide dispersed phase with a particle size of 130 nm in an amount of up to 10 wt. % using the SHS method, which makes it possible to increase the hardness of the alloys. Additional heating of the AMg2–10%TiC and AMg6–10%TiC samples after synthesis also contributes to the further increase in hardness. The complex of studies of physical, mechanical and operational characteristics presented in the paper was carried out to compare the properties of the work-hardened matrix alloys and the samples of composite materials before and after heating. The test results showed that heat treatment reduces the porosity of the composites and significantly increases their hardness and microhardness. A slight decrease in compressive strength at a significant increase in wear resistance is observed. It was found that composite materials are characterised by high corrosion resistance to carbon dioxide and hydrogen sulfide corrosion corresponding to the level of matrix alloys. The results obtained allow recommending the developed materials for the production of parts of the connecting rod and piston group, bearings and other wear-resistant parts of friction units.

The structure and elemental composition of titanium foil annealed in an inert ambient in the presence of hydrocarbons are studied by optical microscopy and scanning electron microscopy. The heat treatments carried out are simulated the synthesis process of multi-walled carbon nanotubes. As a result of the treatments, the plasticity of the material under study is significantly reduced. It is shown that the structure of the foil changes as a result of annealing. With an increase in the annealing temperature, an increase in carbon and oxygen concentrations is observed, and the hardness of the material increases significantly, which is probably due to the formation of titanium oxide and titanium carbide in the foil structure.

The paper presents a study of the effect of laser irradiation of crystalline chalcogenide films of lead selenide (PbSe) on their electrical characteristics caused by irreversible modification of the structure due to valence reconfiguration of lead as a result of its oxidation. The study of the modification features of the electrical properties of the films was carried out because of laser exposure to nanosecond pulses with a wavelength of 1064 nm. Measurements of the electrical characteristics of PbSe films were carried out using the four-probe method. It was shown that when the current was directed parallel to the laser tracks recorded in the darkening mode, the resistance of the modified film decreased by 44 % compared to the original sample, and with the perpendicular direction of the current, the resistance increased by 153 %. The resistance of the film increased more than 27 times after laser irradiation in the bleaching mode, regardless of the direction of the current relative to the laser tracks. The experimentally measured temperature and its gradient along the laser spot on the film in the darkening and bleaching modes turned out to be in good agreement with the proposed mathematical model of the thermal effect of laser pulses. It has been shown that the processes of laser modification of films occur at lower temperatures than during standard heat treatment in a furnace. The obtained results can be applied in the development of photodetectors in the middle IR range of the spectrum based on PbSe film.

The processes occurring in the silicon-oxygen-nitrogen system are of great practical importance, since dielectric layers made from materials of this system are widely used as barriers to the penetration of impurities, elements of storage capacitors, field insulating layers, etc. Interest in the creation of such dielectrics has increased in connection with the use of the rapid thermal annealing stage in technological processes, which are accompanied by the appearance of fast surface states and mechanical stresses on the interface. As a result of the study, it was determined that the change in the threshold voltage in MDS structures is associated with the capture of electrons by the traps formed in the bulk of the semiconductor. MDS structures with nitrided oxide have better stability than conventional oxide. Studies have shown that the suppression of the formation of states at the interface depends on the degree of nitriding. The characteristics of MDS structures under the influence of irradiation substantially depend on the temperature and duration of fast thermal nitrization.

The slowest heating zone tends to move about in food systems with convective and predominantly convective heat transfer. If the thermocouple follows the movement, the process lethality differs from the value precalculated for a fixed thermocouple location. Hence, the heat treatment modes depend on the movement of the slowest heating zone, which should be taken into account before planning food system processes. This research aimed at identifying a statistically significant difference between lethality for fixed and moving slowest heating zones in various food systems. The study involved four homophasic and heterophasic model food systems. Food System 1 was heterophase, with a dispersed phase not involved in convection and a liquid dispersion medium of aqueous solution with 1.5% sucrose and 1.5% NaCl. Food System 2 was heterophase, with a dispersed phase not involved in convection and a liquid dispersion medium of 11% aqueous sucrose solution. Food System 3 was represented by homophase reconstituted clarified baby-food apple juice with 11.2% soluble solids. Food System 4 was a heterophase model system, represented by reconstituted baby-food apple juice with pulp and 11.2% soluble solids with a dispersed phase involved in convection. The temperature changes were monitored using the E-ValPro multichannel system and the SSA-TS model temperature sensors. The temperature sensors were fixed inside the jar with the food system. Food System 1 showed no significant differences in lethality. Other model systems had sterilization temperature intervals when the difference in lethality was statistically significant. However, this difference was very small for Food Systems 2 and 3. The largest difference belonged to Food System 4, where the dispersed phase was involved in the convective flow. In this research, a statistically significant difference in lethality for fixed and moving slowest heating zones occurred only in heterophase food systems with convective and predominantly convective heat exchange, where the dispersed phase was involved in the convection flow. This fact must be taken into account when identifying heat treatment modes for such food systems.

Sliced veneer has the highest value as a facing material, provided that the natural color of the wood is preserved. Therefore, the study of the color characteristics of sliced veneer is of considerable practical importance. The object of the study is sliced veneer from European oak wood (Quercus robur L.), since it is produced in significant quantities by Ukrainian enterprises. The experimental studies were carried out under the production conditions of the Euroshpon LLC, which specializes in the production of sliced veneer. The color properties of sliced veneer were studied using the CIELab chromatic system. During the experimental studies, the duration of the steaming process was 16 hours at a steam temperature of 115°C, and the boiling process was 36 hours at a water temperature of 98°C. The sliced veneer samples were taken at a depth of 5 cm, 10 cm, 15 cm from the surface of the specimens for atmospheric drying and kept at a temperature of 20 °C and relative humidity near 50% during 14 days (for chamber drying at a temperature of 135 °C - within 120 s). In order to determine the natural color of oak wood, a reference sample of sliced veneer was taken, obtained from wainscots that had not undergone hydrothermal treatment. The sample was taken based on its uniform texture and color and obtained from logs that had not undergone hydrothermal treatment. Also, this sample was not subject to kiln drying. During the heat treatment (steaming, boiling), the temperature distribution across the cross section of the sample is not uniform. Wood at a depth of 50 mm warms up faster and to higher temperatures than at depths of 100 and 150 mm. According to the results of the experimental studies, the сolor scale readings of the reference sample are as follows: L*=65.80; a*=6.59; b*=23.39. The brightness of sliced oak veneer made from steamed wainscots and dried in the atmospheric conditions is L*=63.57-65.52, while the brightness of the sample dried in a drying chamber is L*=62.79-65.09. The brightness of sliced oak veneer made from boiled logs and dried in the atmospheric conditions is L*=63.82-65.43, the brightness of the sample dried in a drying chamber is L*=63.55-64.88. The parameter a* for sliced veneer sample taken from steamed wainscots is a*=5.03-5.58, and for sliced veneer sample taken from boiled wainscots is a*=6.24-6.97. The parameter a* for sliced veneer taken from steamed wainscots is a*=5.03-5.58, and for sliced veneer sample taken from steamed wainscots, the parameter a*=6.24-6.9 The component b* for sliced veneer sample taken from steamed wainscots is b*=20.21-20.85, and for sliced veneer sample taken from steamed wainscots – b*=20.47-20.99. The obtained research results can be applied in production conditions for the purpose of adjusting hydrothermal treatment modes and other processes in the manufacture of sliced oak veneer. The technological operation of oak logs boiling in the production of sliced veneer is recommended to be used in the case when it is necessary to achieve a lighter and more uniform color of the veneer, taking into account a longer process of heat treatment. Steaming oak logs has some advantages when it is necessary to increase manufacturing productivity without taking into account the color characteristics of the veneer.

The effect of preliminary heat treatment on the morphology of carbon layer formed on the surface of chlorinated polyvinyl chloride with the addition of ferrocene (10 % of polymer weight) under the impact of a high-power nanosecond-durable ion beam has been studied. Preliminary exposure of samples in an oven at different temperatures for 1 hour leads to partial dehydrochlorination of the surface layer of the polymer film and interchain crosslinking, creating centers for the start of the carbonization reaction, and thus affects the formation of carbon nanostructures during subsequent irradiation with a high-power ion beam. The possible mechanism of carbon nanostructures formation from chlorinated polyvinyl chloride under the impact of a high-power ion beam and the mechanism of the influence of preliminary heat treatment on it are considered. It has been established that different heat treatment temperatures lead to different morphologies of the resulting carbon nanostructures. On the control sample and the sample subjected to heating to 100 °C, only nanofibers are formed, preheating to 150 °C leads to the formation of a porous structure with nanosized pores under the nanofibers, and preheating to 200 °C leads to a significant decrease in the porosity and concentration of nanofibers.

H-NMR spectroscopy was used to study the metabolic profile of Atlantic salmon muscle tissue during heat treatment and storage to assess the taste of products. It has been established that when steaming fish, the amount of compounds such as trimethylamine (TMA), taurine (Tau), glutamic acid (Glu), lysine (Lys), proline (Pro), serine (Ser), γ-aminobutyric acid (GABA), creatinine (Cret) increased in broth compared to raw fish, and Tau and Cret accumulated in cooked fish. The content of TMA, which gives a fishy smell to the product, increased dramatically in cooked fish, regardless of the cooking duration, and at the same time an increase in dimethylamine (DMA) was observed in cooked fish. The processing of the data array of the content of metabolites by the method of principal components was carried out and a clear separation of fish and broth samples was revealed, as well as the difference between fish stored for a long time and the original sample. The taste qualities of fish raw materials before and after heat treatment were evaluated using the taste active value (TAV) of the main compounds characterizing sweet, bitter, sour tastes, as well as umami taste. The values of the taste threshold of compounds, which are widely used for a comprehensive assessment of various food products, were taken for calculations. The TAV for the broth when steaming Atlantic salmon for 30 min was 6.27 ± 0.06, and with an increase in time to 60 min, it decreased to 5.61 ± 0.09. During long-term storage of fish, there was a sharp decrease in the umami taste index and an increase in bitter taste, which is due to hydrolytic processes occurring during product spoilage. It is concluded that the NMR spectroscopy method makes it possible to quantify the change in the main metabolites in Atlantic salmon samples during heat treatment and storage, and TAV calculated from the content of free amino acids, nucleotides and organic acids provides an objective description of the taste of the product.

Friction stir processing is one of the modern methods of local modification of the surface of aluminum alloys in the solid-phase state, which provides the dispersion of structural components. In heat-hardened aluminum alloys with a matrix type structure, heat treatment following after friction stir processing can lead to abnormal grain growth in the stir zone. However, in alloys with the structure close to microduplex type, a fine-grained structure can be formed after friction stir processing and heat treatment. This work is aimed at evaluating the possibility of increasing the microstructure thermal stability of the AK4-1 (Al–Cu–Mg–Fe–Si–Ni) matrix-type aluminum alloy. For this purpose, AK12D (Al–Si–Cu–Ni–Mg) aluminum alloy with the structure close to microduplex type was locally mixed into the studied alloy by friction stir processing. Subsequent Т6 heat treatment was carried out according to the standard mode for the AK4-1 alloy. Studies showed that the stir zone had an elliptical shape with an onion-ring structure. This structure comprised alternating rings with different amounts and sizes of excess phases. At the same time, in the stir zone center, the width of rings and the average area of excess phases were larger compared to the stir zone periphery, where the width of rings and the average area of particles were smaller. The average area of excess phases in the rings with their higher content was smaller than in the rings with their lower content. This distribution of excess phases leads to the formation of a fine-grained microstructure, where the average size of grains depends on the interparticle distance in the α-Al solid solution.

Additive technologies for making products by laser melting of powders have been rapidly developed recently. However, such technologies impose increased requirements on the properties of alloys used for the manufacturing of parts. Laser-melting technologies are a promising direction in the development of metal products due to several advantages, such as (1) the possibility of manufacturing complex-shaped parts with internal cavities and thin partitions; (2) significant material savings due to the precise manufacturing of part of a given shape according to a computer model that does not require the use of subsequent conventional turning, milling, and cutting operations; (3) achieving a higher level of mechanical properties due to increased cooling speeds compared to standard technologies by means of the formation of a more dispersed structure.

The effect of thermal treatment on the behavior of samarium atoms introduced into silicon during the growth process was studied using the method of transient capacitive deep-level spectroscopy (DLTS). It has been shown that various high-temperature treatments lead to the activation of samarium atoms in the bulk of n-Si and the formation of deep levels. The energy spectrum of deep levels arising during heat treatments has been determined. The dependence of the efficiency of formation of these levels in n‑Si on the processing temperature has been studied. It was found that the higher the content of samarium atoms in the bulk of silicon at the same high-temperature treatment temperature, the higher the concentration of the deep level EC–0.39 eV. From this, we can conclude that the EC–0.39 eV level is associated with the activation of samarium atoms in the n-Si volume.

The article provides an overview of the existing methods of early loading of monolithic structures. It is shown that keeping concrete up to standard strength without taking into account the stages of loading leads to a significant increase in the cost of work, especially in winter. Based on experimental studies, formulas are proposed for calculating the required strength by the moment of loading of monolithic foundations, walls, columns, ceilings. Instructions are given on the design of early loading technology. The results of full-scale tests of floors under conditions of early loading are given. The technology of tiered heat treatment of monolithic structures is described.

Natural metal composite materials represent a promising class of modern structural materials that need to be welded. Such materials can be welded by fusion, as has been established with the Ti-TiB alloy as an example. The enhanced operational properties of such materials are determined by the microstructure, which is characterized by the presence of microfibers of borides, carbides, or silicides in the metal matrix. To preserve the mechanical properties of materials in a welded joint, it is necessary to ensure the formation of reinforcing microfibers in the welded seam material. Determination of formation mechanism of boride microfibers, originated in the welded seam material, will become the basis for optimizing of fusion welding modes, in particular, electron beam welding mode. The purpose of this study is the determination of formation mechanism of boride microfibers originated in the welded seam material. Two most probable variants of the formation mechanism are analyzed, which involve eutectic decomposition during crystallization from a liquid melt or eutectoid decomposition from a metastable crystallized alloy. The third version is a mixed variant of the two above-mentioned mechanisms. In the article the results of metallographic analysis of features of boride phase distribution and an analysis of elemental composition of boride fibers based on local Auger electron spectroscopy are presented. The object of study was a Ti-TiB alloy joint obtained by electron-beam welding. The analysis factors were the features of size, orientation, and nature of the distribution of boride phase microfibers in different areas of the welded seam. The characteristic elemental composition of boride microfibers, which characterizes the correspondence to equilibrium phases, is also studied. The degree of deviation of the ratio of boron and titanium in such a phase from the thermodynamically equilibrium in different layers of the material of the welded seam, formed by an electron beam in vacuum, is determined. The dependence of boride phase distribution under various conditions of heat exchange in the welded seam material on the side surfaces and in the central regions is established. It is shown that some of boride microfibers formed in the material of the welded seam are characterized by a deviation from the thermodynamically stable composition ТіВn (n = 1) to ТіВn (n = 0.85). The dendritic nature of boride microfibers distribution and the presence of meta-stable phase formations on Ti and B basis provide the grounds for proposing the predominant mechanism for the formation of structure of the welded seam material in the Ti-TiB alloy during crystallization. An analysis of hypothetical variants of the formation mechanism of boride microfibers originated in the welded seam material showed that the formation of a dendritic type of structure is characteristic for the growth of crystals of a new phase in the liquid phase. Such growth is characterized by the formation of equilibrium phases. The presence of a significant amount of non-equilibrium boride phase in the welded seam indicates the residue of non-equilibrium boron in the titanium matrix and continuation of growing of boride fibers in the crystallized welded seam. A determined mechanism for formation of boride microfibers originated in the welded seam material is eutectic decomposition during crystallization from a liquid melt with the formation of TiB microfibers and further growth of such crystals due to eutectoid decomposition from a metastable crystallized Ti-TiB alloy. The results obtained make it possible to understand the mechanism of formation of a welded seam in welded natural-composite metal materials, which permits to develop the recommendations for optimizing the welding technology for such materials.

Growing productivity of mining and processing enterprises entails an increase in the volumes of liquid tailings impoundments and upstream impoundments of ore processing waste. Enterprises face the challenge of minimizing the environmental impact of waste and guaranteeing the sanitary and epidemiological safety of population. The article presents a possibility of recycling one type of such waste (clay-containing concentration tailings of apatite-nepheline and sylvinite ores, coal beneficiation tailings) by using them after preliminary thermochemical treatment as pozzolanic additives to cements and concretes, including concrete mixtures used for soil stabilization, development of territories, reclamation of mine workings, as a component of the insulating layer of landfills for the disposal of municipal solid waste. An analysis of the phase changes of kaolinite, one of the main minerals that make up clay-containing waste, in the temperature range of 200-1,000 °С showed that a change in its mineral form during heat treatment is the main factor in changing its pozzolanic activity. The effect of heat treatment of clay minerals at temperature of 700-800 °C on their pozzolanic activity, estimated by the ability to absorb calcium hydroxide (0.7 g Ca(OH)2 per 1 g of modified kaolinite), is considered. It is shown that the addition of heat-treated samples (20 % by weight) improves the quality of cement increasing its activity by 15 %, in comparison with the use of unmodified clay minerals. It was proved experimentally that partial replacement of Portland cement with thermally modified kaolinite increases the strength of consolidating stowing mixture by up to 15 %. This approach to processing of ores containing layered silicates, which provides for thermochemical modification of run-of-mine ore, intensifies the processes of tailings thickening and filtering.

Relevance. Titanium and its alloys are the most durable and corrosion-resistant metal materials that makes them widely used in mechanical engineering, aircraft and machinery, chemical apparatus construction, medicine. The use of such construction materials with increased resistance in aggressive environments makes it possible to increase the efficiency of technologies for processing natural raw materials (high-pressure reactors, centrifuges, separators, high-speed pumps, heat exchangers, communications), the production of chlorine and alkalis (evaporators, electrolysis equipment), organic synthesis (equipment for the production of halogen derivatives), the production of nitric acid, ammonia and nitrogen fertilizers. The combination of mechanical and thermal treatment of alloys, including the use of severe plastic deformation, allows modifying their structure and obtaining materials with improved physical and mechanical characteristics. Purpose: to determine the effect of various modes of the deformation and heat treatment of titanium alloys VT6 and VT22 on their corrosion resistance in aqueous solutions of acids, alkalis and salts. Objects: samples of VT6 and VT22 alloys with different structures, aqueous solutions of acids, alkalis and salts. Methods: DC voltammetry, gravimetry under conditions of free corrosion, optical microscopy, scanning electron microscopy, X-ray diffractometry, atomic emission spectroscopy. Results. Under conditions of severe plastic deformation, samples of titanium alloys VT6 (triaxial pressing in the temperature range from 550 to 800 °C) and VT22 (radial shear rolling in the temperature range from 750 to 850 °C, additional cold rolling of hot-rolled samples, aging at 550 °C for 3...6 hours) with ultrafine-grained structure have been produced. It was found that VT6 alloy with ultrafine-grained structure has less corrosion resistance under conditions of free corrosion in solutions of sulfuric acid of a high concentration (5 M), as well as in 3,5 % NaCl solution at anodic polarization compared to the initial alloy with coarse-grained structure. The main types of corrosion damage to the surface of the ultrafine-grained samples were ulcers and pitting, whereas for samples with a coarse-grained structure, continuous corrosion was characteristic. The increase in the rate of corrosion and morphological features of the destruction of the surface are explained by structural-phase heterogeneity and segregation of alloying elements as a result of the deformation and thermal effects. The corrosion resistance of VT22 samples with an ultrafine-grained structure correlates with the content of the b-phase and with the features of the interphase distribution of alloying elements resulting from the polymorphic transformation of a-TiDb-Ti under conditions of the deformation and heat treatment. It is shown that VT22 samples after hot rolling are the most stable in acid solutions (0,1 M HCl, H2SO4) and the least stable in alkali solution (0,1 M NaOH) compared to samples treated under other regimes. In a 3,5 % NaCl solution, the ultrafine-grained sample VT22 showed the least resistance after additional cold rolling due to a large concentration of structural defects that contribute to increased corrosion cracking of the material. The interpretation of the experimental results was carried out using theoretical calculations of the equilibrium composition of corrosion products formed in the multicomponent systems under study.

ABSTRACT: Introduction. The aim of the work is to determine the influence of the structure of the filter materials formed as a result of modification of the surface layer on their water permeability and the size of trapped solid particles. Materials and methods. The non-woven fabrics from a mixture of polyethylene-terephthalate (PET) (70 wt.%) and bicomponent fibers (BCF) of the coreshell structure were used as objects of the study. The non-woven fabrics were obtained by mechanically forming the canvas with its subsequent hardening by needle punching. The resulting materials were modified by heat treatment. The water transfer in the modified materials was determined by the permeability coefficient. The filtration efficiency was determined by the number of trapped particles of a certain size. Results and discussion. The needle-punched non-woven fabrics without additional heat treatment are not suitable for water filtration. The proposed method of thermal and deformation-thermal modification provides the production of gradient materials with a controlled thickness of the nanoscale surface layer. Although a decrease in water permeability is observed, the modified material traps solid particles with a smaller (compared to unmodified ~ 20 µm) equivalent diameter of 2–4 µm, which is sufficient to prepare water for use in steam generators and in the production of building materials. Conclusion. The optimal parameters of deformation-heat treatment for obtaining the high-effective filtration non-woven materials were established: the temperature – 180оC, the processing speed – 3.5 m/min.

Ring blanks are in demand in various branches of mechanical engineering in the production of large-sized bearings, turbine disks, special gears and other critical products. Besides high requirements to the ring blanks in terms of geometric dimensional accuracy, material structure and mechanical properties, in some cases the most important requirement is their production with absence of residual stresses and high stability of geometric shape. Specific features of ring rolling may lead to the occurrence of residual stresses, the magnitude of which is impossible to determine by the known methods of defect control. The paper analyzes the causes of shape error and residual stresses in the production of ring blanks in the process of ring rolling and heat treatment. The article also assesses the possibility of using different methods of shape stabilization and reduction of residual stresses in the manufacture of ring blanks for critical engineering products: expandable, thermal, thermomechanical, vibratory and ultrasonic treatment. For ring blanks designed for manufacturing critical parts, it is suggested to use shape stabilization and residual stresses reduction by means of cyclic loading after ring rolling and thermal treatment. The design scheme and force parameters of a device for stabilizing ring blanks on the basis of a double-acting lever-hinge mechanism are determined. The ring-rolling complex created at the Belarusian Automobile Plant will have potential opportunities to produce ring blanks for manufacturing of critical products in transport machine-building, aviation, space, defense and chemical industries of the Russian Federation. The results of the analysis of the methods for shape stabilization and reduction of residual stresses of ring blanks are planned to be used in the creation of this complex.

In recent years, metal additive manufacturing (AM), also known as 3D printing, is grown massively in the industry. The ability of AM to build parts directly from the digital representation makes it an excellent alternative compared to traditional manufacturing technologies, such as milling, welding, casting, rolling, stamping, forging, and turning for rapidly making highly customized parts. Currently, a number of different powder- and wire-based AM technologies are developed for the 3D printing of metals. A number of potential benefits of AM are noted, including the allowance of design freedom, complex parts’ production, material waste, part weight reductions, and material use minimization; it also saves the time and money of the production cycle times. Due to the feasibility of economically producing large-scale metal components with relatively high deposition rate, low machinery cost, high material efficiency, and shortened lead time as compared to the powder-based AM, the wire-based AM significantly attracted the industry and academia due to its ability to produce the large components of the medium geometric complexity. During this AM process, the wire is fed at a controlled rate into the melt pool produced by the electric arc, laser, or electron beam as the heat source. In the past few decades, basic research and development efforts are devoted to the wire-based 3D printing parts made of Ti–6Al–4V alloy, which has been widely investigated and used in different fields such as aerospace, automotive, energy, marine industries and in addition to the prosthetics and the orthopaedic implants. Numerous studies in recent years on the influence of the 3D printing parameters have shown a significant difference in the mechanism and kinetics of the microstructure formation in the Ti–6Al–4V alloy samples compared to traditional technologies. It is well investigated that the mechanical properties of such alloy are dependent on the solidification macro- and microstructure, which is controlled by the thermal conditions during 3D printing. In the present review, the main microstructural characteristics, which determine the mechanical properties of the two-phase Ti–6Al–4V alloy, are analysed for the samples obtained by wire-feed 3D printing with various sources used for the wire melting, namely, the electric arc, the laser, and the electron beam. At first, the review introduces the links between the process parameters, and resultant microstructures, especially, the morphology, the size and the quantitative ratio of the α and β grains in the as-printed Ti–6Al–4V alloy samples. However, the metallic products manufactured by a vast majority of the AM processes need to be post-processed by heat treatment and/or hot isostatic pressing, which are also discussed in this review.

Introduction. The purpose of this work is to study the thermally modified peat additive, the use of which is scientifically justified in the works of professor N.O. Kopanitsa and her colleagues. This additive is extracted from the raw materials from the Kaliningrad region, and the authors focus on its effect on the consistency, moisture-retaining capacity of the mix, and the strength characteristics of fine-grained concrete.Materials and methods. The additive was made from lowland peat extracted from the Glushkovo quarry in the Kaliningrad region. Raw materials were subjected to thermal treatment with limited access of oxygen.Results. The authors have proven an increase in the consistency and water-retaining capacity of mixes that have 4 and 8 % additive. On the 21 day, an 9 % increase in the flexural strength of concrete specimens with the 4 and 8 % additive was registered in comparison with the benchmark specimen (5.5 MPa for the benchmark mix and 6 MPa for the 4 and 8 % additive); an increase in compression strength reached 23 % when the 8 % additive was used (40.7 and 50.2 MPa for the benchmark mix and the one that contains the 8 % additive, respectively).Conclusions. The presented results of the research show a strong potential for the improvement of physical-mechanical properties of concretes by using thermally modified peat additives made from the local raw materials extracted in the Kali­ningrad region.

One of the promising research areas developing in recent times in the materials science is the development and research of high-entropy alloys containing several metal elements with the concentration close to equiatomic. The interest to them is generated by the fact that such alloys demonstrate the improved mechanical and functional properties. Another promising area improving strength of metallic materials is grain refinement using the severe plastic deformation methods. This work uses both approaches to form an ultrafine-grained (UFG) structure in the high-entropy Fe30Ni30Mn30Cr10 alloy. The paper presents the structure, strength, thermal stability, and corrosion resistance of a high-entropy alloy subjected to the high pressure torsion (HPT). The study of the structure carried out by scanning electron microscopy showed that the application of the HPT deformation leads to the formation of an UFG structure with an average grain diameter less than 200 nm depending on temperature of HPT processing. Microhardness measuring and tensile tests at room temperature showed that after grain refinement, an increase in microhardness and ultimate tensile strength occurs in a high-entropy alloy, which is more than three times higher compared to the initial coarse-grained sample. At the same time, the UFG samples of a high-entropy alloy manifested thermal stability of microhardness after annealing up to temperature of 500 °С. The electrochemical tests carried out in an aqueous solution of 3.5 % NaCl at the temperature of 37 °С demonstrated a high corrosion resistance of the UFG high-entropy alloy.

Introduction. The purpose of this work is to study the thermally modified peat additive, the use of which is scientifically justified in the works of professor N.O. Kopanitsa and her colleagues. This additive is extracted from the raw materials from the Kaliningrad region, and the authors focus on its effect on the consistency, moisture-retaining capacity of the mix, and the strength characteristics of fine-grained concrete. Materials and methods. The additive was made from lowland peat extracted from the Glushkovo quarry in the Kaliningrad region. Raw materials were subjected to thermal treatment with limited access of oxygen. Results. The authors have proven an increase in the consistency and water-retaining capacity of mixes that have 4 and 8 % additive. On the 21 day, an 9 % increase in the flexural strength of concrete specimens with the 4 and 8 % additive was registered in comparison with the benchmark specimen (5.5 MPa for the benchmark mix and 6 MPa for the 4 and 8 % additive); an increase in compression strength reached 23 % when the 8 % additive was used (40.7 and 50.2 MPa for the benchmark mix and the one that contains the 8 % additive, respectively). Conclusions. The presented results of the research show a strong potential for the improvement of physical-mechanical properties of concretes by using thermally modified peat additives made from the local raw materials extracted in the Kali­ningrad region.

The purpose of the paper is to present the features of the development of ironworking of the Volga-Kama periphery of the Eastern European part of the Barbarikum on the basis of data obtained during the metallographic study of forged pieces related to the materials of the Imenkovo culture (V–VII centuries), that were found in different years (mainly by P.N. Starostin in the 1960s–80s) on the part of the Shcherbet I settlement destroyed by the reservoir. Schemes and methods of making 31 items made of ferrous metal were determined: a ploughshare, a chisel, 2 axes, 4 sickles, 13 knives, 4 awls, 2 rings for fastening, two fishhooks and two rod-shaped items. It was found that forging welding and local carburizing were often used in their manufacture. Half of the objects had traces of heat treating in the tempering mode or in a soft temper milieu. As a characteristic technological feature of this collection, a combination of iron and steel forgings (usually low-carbon) components is noted in the design, mainly in the form of upset welding or welding of a strip bent in half. A significant mass of items have distinct signs of multi-layer packing. The degree of using of blacksmithing skills and the quality of the studied items on the example of the examined samples give reason to believe that the ironworking of the Imenkovo culture had a deep-seated tradition.

The condition for stable fixation of a collector on the surface of diamonds and their flotation is the use of collectors of the optimal fractional composition and the choice of the optimum temperature regime of the process. To determine the parameters of the diamond flotation regime, the regularities of the phase transitions of asphaltene-tar fractions at increasing temperature and diluting F-5 with technical diesel fraction were established. It was demonstrated that increasing the collector temperature leads to the transfer of asphaltenetar fractions to a dissolved and finely dispersed state. To an even greater extent, dissolving asphaltene-tar fractions is facilitated by the addition of medium- and low-molecular weight fractions of oil, for instance, a technical diesel fraction. It was revealed that the KM-10, KM-14, and KM-18 reagents, being compounds of F-5 fuel oil with technical diesel fraction (10–18 % DF), were characterized by optimal viscosity and ability to displace aqueous phase from a diamond surface, thus ensuring stable hydrophobization and high floatability of diamonds. The optimal temperature regime has been selected, which involved maintaining the temperature at the stage of conditioning with the collector at +30–40 °С, at which the maximum selective fixation of compound collectors on the diamond surface, characterized by the value of the limiting wetting angle, was achieved. The flotation tests have confirmed that the best results are achieved at a temperature of +30–40 °С at the conditioning stage and +14–24 °С at the flotation stage. At +24 °С, the best results were obtained for the relatively less diluted KM-10 and KM-14 fuel oils obtained by diluting F-5 fuel oil with a technical diesel fraction at the diluent volume fractions of 10 and 14 %. The diamond recovery achieved in the flotation tests was 3.8–4.5 % higher than when using the traditional collector, F-5 fuel oil. At +14 °С, the highly diluted fuel oil, KM-18 with a volume fraction of 18 % of the technical diesel fraction, demonstrated better collecting abilities. The optimal compositions of the collector and the regimes of feed preparation and flotation were tested at a foam separation unit. The tests showed that it is possible to increase diamond recovery into concentrate by 2.3–4.5 %. The recommendations are provided on the use of thermal conditioning in the foam separation cycle and maintaining the conditioning medium temperature at +30–40 °С and the foam separation temperature at +14–24 °С.

Data on the biological and nutritional value of quail meat have been studied. The use of quail meat and product development have been substantiated on the materials and technical basis of KubSAU named after I.T. Trubilin. As a result of the research, biotechnological requirements for the composition and quality of the developed products intended for preschool children have been analyzed, the qualitative characteristics of the main raw material, i.e. quail meat and additional raw materials have been selected and assessed. By the method of calculating the quantitative and qualitative characteristics of the selected ingredients, a combination of formulation components with a hypoallergenic effect has been determined. The modeling of prescription compositions of products containing dietary raw materials of low allergenic activity has been carried out, a technology for the production of products developed, including the heat treatment of whole quail carcasses, which has made it possible to reduce the loss of meat juice to 35.8% against 55.17% during heat treatment of deboned meat. Experimental batches of food products for the nutrition of pre-preschool children have been developed, followed by an assessment of the nutritional and biological value. The daily satisfaction of toddler children in the main nutrients has been studied. The developed boiled sausage product and meat souffle meet the requirements for protein content of 13.37 and 14.6; fat 16.56 and 4.4; salts 0.72 and 0.4, respectively.

The manufacture of products using additive technologies is accompanied by the unpredictable appearance of inhomogeneity of properties, anisotropy, residual stresses, porosity, and other defects. Therefore, there is a great relevance of non-destructive quality control of products obtained by additive technologies. The purpose of the paper is the experimental investigation of the possibility of testing and evaluation of the quality of heat treatment of three-dimensional and cast samples by non-destructive control methods.The low-alloy steel 09G2S samples, which was obtained by casting and selective laser sintering different modes of subsequent heat treatments were studied. The method of the Barkhausen effect and the instrumented indentation method for measuring the material hardness were applied.It was experimentally established that both methods are highly sensitive to annealed and normalized three-dimensional samples and their rejection. Compared to the hardness measurement method, which is mainly associated with phase-structural changes, the magnetic noise method due to selectivity to other controlled parameters is additionally sensitive to cast samples (at the same time the microstructures of cast and normalized three-dimensional samples are close to each other according to X-ray data).The magnetic noise method can be used as one of the physical methods for evaluation the quality and control of the heat treatment of 3D samples at the manufacturing stage when testing their types and modes, as well as sorting samples.

Objectives. To quantitatively describe the thermochromic properties of films of isotactic polypropylene, a large-tonnage polymer widely used in the production of flexible packaging for goods and foodstuffs, as well as substantiate the possibility of covert labeling of transparent packaging.Methods. Differential scanning calorimetry, polarization photometry, infrared Fourier spectrometry, gravimetry, temperature control, physical and mechanical strength testing.Results. The identified thermochromic effect of dichroism in polarized light on industrial samples of transparent biaxially oriented film of isotactic polypropylene was studied. A change in the phase composition of the film-forming composition during short-term heating during marking was established. The absence of heat shrinkage and change in transparency in non-polarized light was shown, which provides the possibility of hidden recording of information and its contrast manifestation in a passing light stream at a certain arrangement of light filters.Conclusions. The causes and optimal conditions of the thermochromic effect are established. It is proposed to use local contact heat treatment of a polypropylene film for covert recording of information and marking of product packaging in order to protect against counterfeiting.

Analysis of literature data shows the uncertainty of a number of issues of the starch dextrinization process, namely the patterns of the change in the crystal structure of starch during heat treatment and the dependence of the viscosity of starch pastes of dextrins on the conditions of starch heat treatment. These questions were chosen as the topic of this study. A decrease in the average size of starch particles by 2.7 mm and an increase in the intensity of reflexes of diffractograms in the range of 26=10-20°after its heat treatment at 135°C (the temperature at which the dextrinization process starts) are well explained by dehydration and a change in the degree of crystallization of biopolymer macromolecules due to their thermal transformations. The dependence of the dynamic viscosity of hot pastes on their shear rate was studied. The steady shear flow curves showed the presence of dilatant areas as a transition from the Newtonian flow regime to the pseudoplastic flow of starch pastes. It was found that the viscosities of heat-treated starch pastes depend on the processing conditions; the viscosities increase in the following order: starch heat-treated in the presence of an acid catalyst; native starch; starch heat-treated without a catalyst for 5 hours; and starch heat-treated without a catalyst for 2.5 hours. It was proposed to divide dextrins into two separate groups: with an increased and with a reduced degree of amylose polymerization. [ABSTRACT FROM AUTHOR]

In Ukraine, in today's conditions, snails, which are widely used for food in a number of European countries, are of increased interest. Over the past few years, this type of shellfish has been intensively harvested for processing and exporting abroad. However, there is not much data on the nutritional properties of snail meat, and there is practically no such information in Ukraine. The aim of this study is to determine the chemical composition (wet, dry matter, and energy value) of raw and cooked snail meat Helix aspersa maxima, Helix aspersa muller, Helix pomatia and conducting their comparative analysis among themselves with other types of meat. Indicators of nutritional properties were determined according to the following methods. The moisture and fat content was determined according to DSTU ISO 1442:2005; DSTU ISO 1443:2005, respectively. The mass fraction of dry matter, protein, ash, and caloric content of meat was determined by the methods described by P.V. Zhitenko and others. Comparative analysis of snail meat with other animal species was carried out based on literature sources. In the study, the authors found that on average in snails of the following species: Helix aspersa maxima, Helix aspersa muller, Helix pomatia it contains moisture – 72.03±0.29% and dry matter – 27.97±0.29%, of which: protein – 22.83±0.3%, fat – 0.23±0.03%, carbohydrates – 2.07±0.17%. It was determined that the indicators of moisture, dry matter, protein, fat, carbohydrates, ash and energy value in snails of all three species taken in the experiment did not differ significantly from each other. At the same time a sample of boiled snail meat Helix pomatia it has a higher chemical composition compared to the other two types of snails, namely: dry matter (28.5%), protein (23.4%), fat (0.3%) and energy value (103.9 kcal/100 g). Comparing the obtained data on the study of the chemical composition of raw and boiled meat of the same snail species, it was found that boiled meat is 14.2% more energetically valuable than raw, both in kCal/100 g and in kJ/100 g. We consider determining changes in organs at the cellular level, that is, conducting histological studies, taking into account different periods: hibernation, after hibernation and during the active period of their vital activity, to be a promising area of further research

The conditions for choosing a billet mass for the manufacture of an ring part on an automated ring-rolling complex, the features of heating the billets in the conditions of an automated line and heat treatment of manufactured parts are considered. The expediency of differentiated assignment of tolerances for the rings’ sizes after ring rolling, depending on their type, conditions of subsequent mechanical treatment and operation, is substantiated. Attention is focused on the need to design a ring-rolling technology with control of the billet parameters not only during the cutting, heating and pressing operations, but also before the ring-rolling operation, especially when using reheating. To evaluate the technological temperature state of the ring blanks at different stages of manufacturing in an automated line, it is offered to use the billet’s “conventional temperature”, which is determined in the 2nd zone from the middle of the billet. The use of single gas heating of billets in rotary-hearth furnaces in the manufacture of annular billet on an automated line is justified. The problems of the automated ring rolling line and the heat treatment complex synchronization are determined. It is shown that the clock capacity of the automated ring rolling line significantly exceeds the clock capacity of the planned heat treatment complex. It is concluded that it is necessary to develop software for their synchronous operation.The proposed recommendations are intended for the development of technological support for an automated ring-rolling complex at OJSC “PAK Plant” as part of “BELAZ-HOLDING”.

The relationships between the parameters of the structure of heat‑treated steels and their abrasive wear resistance are established. At all temperatures of the final tempering of hardened steel, there is a direct relationship between its structure parameters (the number of elements in a solid solution, the density of dislocations, the size of cementite particles and the intercementite distance) and wear resistance when sliding friction against loose abrasive particles. A computer program has been developed to select the chemical composition of the steel grade and methods of thermal hardening in order to ensure the required wear resistance.

The main reason of decreasing diamond recovery through froth separation is their surface hydrophilization by hypergene minerals and technogenic films, crystallized from the supersaturated aqueous phase, fixed on the surface structurally or by adhesion. Various types of physical actions, including thermal and ultrasonic treatment of the initial feed of froth separation, are recommended to increase the diamond-bearing kimberlite beneficiation process performance, providing cleaning of the surface of diamonds due to destruction of their accretions with rock minerals and removal of film hydrophilizing coatings from the surface of diamond crystals. A sample of kimberlite material with a given content of diamonds of 1.5–2 mm in size was used as a subject of research in the process of froth separation. The results of thermodynamic calculations and experimental research have substantiated the necessity of using electrochemical conditioning of recycled water for increasing the efficiency of diamond surface cleaning in froth separation operation when using the process of thermal treatment of initial ore feed. The use of diaphragmless electrochemical conditioning of recycled water increases the efficiency of thermochemical dissolution of hydrophilizing compounds on the surface of diamonds through reducing the concentration of calcium and carbonate ions as well as through shifting the medium pH to 6.1–6.5. The measurements of the limiting wetting angle showed that the maximum effect of increasing the diamond surface hydrophobicity was achieved when heat and electrochemical treatment were used together. Laboratory studies showed the possibility of increasing flotation diamond extraction from 65.7 to 91.4 % through application of electrochemical conditioning of recycled water. The optimum parameters of diaphragmless electrochemical treatment of recycled water of the froth separation cycle in conditions of application of pulp heat treatment: current density of 175–200 A/m2 and power consumption of 1.2–1.5 kWh/m3. Tests carried out at processing plant No. 3 of the Mirny GOK (Mining and Processing Complex) (Mirny, Yakutiya) showed that the application of the developed froth separation process intensification method with the use of thermal treatment of pulp and electrochemical diaphragmless treatment of recycled water allowed increasing the recovery of diamonds of +0.5–2 mm size by 4.9–5.1 %.

Transportation and refining of heavy metal-bearing oil are associated with the problems of localized destruction of metal structures and elements due to corrosion. In the process of equipment operation, it was revealed that premature failure of steel coils of heating tube furnaces at oil refineries and petrochemical plants was associated with insufficient strength and corrosion resistance of the steelwork. The study of the effect that structure and phase composition of 15KH5M-alloy steel elements of heating furnaces at oil refineries have on the corrosion properties, associated with mass loss and localized destructions in the process of heat treatment, allows to develop protective measures and determine heating modes with a rate-limiting step of oxidation. The rate of various corrosion types of 15KH5M steel is used as an indicator to assess the effectiveness of the applied modes of coil heat treatment in order to increase their corrosion resistance and improve their operational characteristics. Conducted experiments on heat treatment of certain steel coil sections allowed to determine rational heating modes for the studied coils, which made it possible to reduce their mass loss and increase corrosion resistance of working surfaces in the process of operation. Proposed heat treatment of steel coils at specified intervals of their operation in the tube furnaces creates conditions for their stable performance and affects the degree of industrial and environmental safety, as well as reduces material costs associated with the repair and replacement of individual assemblies and parts of tube furnaces.

Within the framework of currently urgent problem of reconstruction and restoration of equipment of thermal power units of TPP, work has been performed on development of basic technology of welding body elements of a steam turbine from low-alloyed 15Kh2M2FBS (P3) steel to branchpipes from high-chromium martensitic X10CrMoVNb91 steel with 9 % Cr (P91). The paper gives the results of determination of the thermal mode of welding such combined joints to prevent delayed fracture. Proceeding from study of the influence of different modes of high-temperature tempering on impact toughness of weld metal and hardness of welded joint areas hardened during welding, heat treatment modes were selected, depending on electrode material type. It is shown that the resultant mechanical properties of welded joints correspond to the requirements specified during work performance. 12 Ref., 5 Tabl., 9 Fig. [ABSTRACT FROM AUTHOR]

Welded samples of Ni3Al intermetallic – the main strengthening phase of high-temperature nickel alloys were taken as an example to defi ne the main problems arising in fusion welding of this class of materials. Features of weld formation, structural and phase changes, and mechanical properties of the welded joints are considered. Conditions of cracks initiation and methods to prevent them are determined. The infl uence of welding modes and heat treatment on the structure, strength and ductility characteristics was studied. Mechanical properties of welded joints in the temperature range of 20…1200 °С were assessed. Schemes and modes of welding and heat treatment are proposed, which allow preventing cracking and ensure equal strength of welded joints and base metal at improvement of their ductility. [ABSTRACT FROM AUTHOR]

Proceeding from the results of literature analysis, the good prospects for application of pressure welding methods, namely diffusion, ultrasonic, and roll welding, when joining elements from magnesium alloys, are shown. Comparative evaluation of welding modes was performed. The main directions for producing sound joints were determined. It is shown that the main ways to improve the welding processes are application of the following approaches: monitoring the temperature-time parameters of welding, application of interlayers in the form of separate layers from similar materials, based on copper, nickel, zinc or silver, or of eutectic mixtures, butt joint strengthening through application of nano- or finely-dispersed particles, intensification of plastic deformation through superposition of ultrasonic oscillations, increase of plastic deformation intensity, as well as application of heat treatment before and after welding. 31 Ref., 1 Tabl., 10 Fig. [ABSTRACT FROM AUTHOR]

The article discusses the results of manufacturing multicomponent consumable cathodes of vacuum electric arc evaporation plants. To obtain ingots of complex silicide as a raw material for the manufacture of target cathodes, it is proposed to use induction melting of pure metal charge materials in an argon atmosphere.The method made it possible to obtain ingots of complex silicide with a composition close to the calculated one and a density of at least 93 %. Further forming of the cathode takes place when controlling the powder fractions by their percentage ratio with a pressing force of at least 50 tons. The results obtained are compared with the SHS method of manufacturing cathodes of identical composition.

The use of non-standard modes of heat treatment increases the density of dislocations in the crystal structure of the α-phase and increases the wear resistance of carbon, low-alloy steels under various friction conditions, which is comparable to the results when heated to a standard temperature (Ac3 + 30–50 °C). The preliminary extreme heating temperature is determined. After requenching at standard temperature and low tempering, the wear resistance of steels under various types of friction increases by up to 40 % compared to standard quenching.

Introduction. The article presents the results of a study of using various methods for thermal processing of bakery products. It is shown that the infrared method is one of the most promising methods of heat treatment. The analysis showed that when combining different methods of heat treatment, the products retain their consumer qualities and the time of the technological cycle is reduced. The author proposes to use the method of thermal processing in the fast food industry. Materials and Methods. The subject of the study is a new method of thermal processing of bakery products made from wheat-rye flour using infrared radiation. For the study, a heating unit was manufactured in accordance with the patent for utility model No. 199820, where heating elements made using the grid-screen printing technology were installed; the performance of heating elements was controlled by a device with a PID controller of the TRM 148-T brand with an RS-485 interface. Results. The article shows that this method can be used to create a uniform product heating. The results of studies on the control of temperature conditions for baking bread are presented. It has been shown that the time of baking bread decreased by more than 25%, while the consumer quality of the product did not change. Discussion and Conclusion. The studies have shown that the use of the method for thermal processing opens up new opportunities for the fast food industry and other sectors of the national economy. The results of the study showed that together with a set of experimental data, this method will be possible to use in the individual sector and to carry out the intellectualization of the process of preparing various food products.