Technological Parameters Research Articles

Аналіз процесу ущільнення порошків вольфраму плакованих міддю

The paper analyzes the pressing process of a composite powder of the tungsten-copper system using the basic mathematical equations describing the deformation processes of a porous body as a function of density and pressing pressure. Several theoretical dependences describing different pressing mechanisms are considered, taking into account modern approaches, namely the discrete-contact model and the continuum model of a continuous medium. The most well-known equations, including those of Balshin M.Y., Zhdanovich G.M., and Shtern M.B., are analyzed. It is established that most of them have limited applicability, remaining valid for individual stages of the pressing process and significantly depend on the mechanical properties of the material that determine the predominance of elastic or plastic deformation. At the same time, most equations are focused on single-component powders, which does not correspond to the practice of powdered parts production processes. To test the theoretical dependencies, copper-clad tungsten powder was obtained by chemical vapor deposition from solution. The technological parameters of the cladding process (composition, solution concentration, and deposition time) that determine the quality of the resulting coatings were determined. The morphology of the particles of clad powders and the structure of tungsten-copper pressings were investigated. It is shown that tungsten powder forms a relatively dense framework with a copper layer, respectively, the structure of composite powder pressings is as close as possible to a continuous continuum and is correctly described by an equation based on the theory of continuity of the medium, It has been established that the compaction character of copper-clad tungsten powder differs from that of single-component tungsten powder, which is due to the fact that plastic deformation mechanisms prevail for tungsten-copper composite powders.

The influence of cutting mode elements on the technological parameters of the process of milling blanks of titanium alloy thin-walled parts

The purpose of a rational mechanical processing mode remains an urgent task of pre-production engineering. Known recommendations and methods for selecting this mode are focused on the processing of solid blanks and do not take into account the fact that when processing thin-walled blanks, the temperatures in the processing zone and the surface layer of the blank differ. The study is aimed at identifying patterns in changing the parameters of the milling process of thin-walled blanks depending on the mode elements, as well as developing recommendations for selecting this mode. The authors performed numerical simulation of technological parameters of the milling process of solid and thin-walled blanks made of titanium alloy under various modes. The cutting speed, cutting depth and feed per cutter tooth were varied. The cutting force, power and densities of heat sources and the temperature in the surface layer of the blank, in the contact zones of the cutter tooth with the blank and the chips with the front surface of the tooth were calculated. It has been found that when milling thin-walled blanks, the temperature field differs significantly from that formed when processing solid blanks due to low heat removal from the unprocessed surface. Increasing the feed per tooth by 45% leads to an insignificant decrease in temperatures in the cutting zone (by 5...12%). Increasing the cutting speed by 25%, on the contrary, leads to an increase in temperatures by 5...10%. Increasing the cutting depth leads to an increase in the temperature in the chip-tooth contact zone by 1.5times and to an increase in the temperature in the tooth-blank contact zone.

Changes in the biological and nutritional value of pea and bean grains as a result of their bioactivation

The relevance of the study is due to the need to improve the technology for processing peas and beans of domestic selection into plant-based drinks and their use in technologies for alternative products of complex raw materials for healthy, functional and specialized nutrition of various population groups. The purpose of the work is to study the influence of the developed technological modes of bioactivation on the nutritional and biological value, functional and technological properties of the protein-carbohydrate complex of pea and bean grains. The work examines the results of studies of changes occurring in pea grains bred at the Bashkir Research Institute of Agriculture and beans bred at the Omsk State Agrarian University during their bioactivation using the Smart Sprouter "Rosinka" installation, in particular the biochemical composition and inhibitory activity of grain of the studied varieties, a protein complex and amino acid composition, protein digestibility in vitro, functional and technological properties of the protein-carbohydrate complex of grain. The research has been carried out using generally accepted, modern instrumental methods for analyzing the properties of raw materials and finished products. It has been established that the use of the developed technological parameters of bioactivation leads to modification of the functional and technological properties of the structure-forming nutrients of grain, intensive accumulation of all amino acids, with the exception of threonine, make it possible to increase the protein content in pea grain by 15.32 % and beans by 14.96 %, relative to the initial values increase the degree of compliance of pea and bean grain protein with the FAO/WHO reference protein by 4.48 and 17.53 %, reduce the activity of grain protease inhibitors by 19.76 and 26.12 %, increase the digestibility of grain protein by 7.77 and 5.85 %. The research results prove the feasibility of using bioactivated pea and bean grains for the production of alternative products with a complex raw material composition, including plant-based drinks and products in the "dairy alternatives" segment.

Thermodynamic analysis of interactions between the components of the charge during the production of metallurgical silicon

The theoretical foundations of the recovery process and the technology of silicon smelting in electric arc furnaces are considered. The results of a study of thermodynamics, reaction kinetics, and mechanisms of the melting process are presented. Production issues are covered: charge preparation, smelting, refining, gas purification. Physicochemical models of the carbothermal process were developed, proposed and tested under industrial conditions (Tau-Ken-Temir LLP), which made it possible to assess the influence of the specified technological parameters of the smelting (chemical composition and loading coefficients of charge components, temperature) on silicon recovery and grade. To obtain the base material, metallurgical grade silicon is used, obtained by melting in ore-thermal furnaces (RTP). In this regard, the research goal is determined, which consists in studying ways to improve the quality (chemical purity) of silicon, and methods for achieving it at this stage of the study - modeling the carbothermal process for producing silicon.The article describes the main mechanism for the recovery of silica in the furnace, presents one of the designs of the furnace and the technological scheme for the production of silicon. The author suggested studying the process of producing metallurgical silicon in RTP using the HSC Chemistry software package. A model of silicon smelting in RTP was formed, which adequately describes the technological process for producing metallurgical silicon.

The Impact of Ganoderma lucidum (Curtis) P. Karst. Supplementation on the Technological, Chemical, and Quality Parameters of Wheat Bread

This study explores the incorporation of Ganoderma lucidum (Curtis) P. Karst. (Reishi mushroom) into wheat bread to develop a functional food with enhanced nutritional value. Reishi powder was added to bread formulations at levels of 3%, 6%, 9%, and 12% to assess its effects on physicochemical, nutritional, and sensory properties. The 12% Reishi supplementation resulted in a twofold increase in total dietary fibre (from 7.21 g to 17.08 g per 100 g dry matter) and significant (p < 0.05) elevations in mineral content, particularly calcium (68%), iron (32%), and manganese (61.9%). Carbohydrate content decreased markedly by 27%, contributing to a 19.33% reduction in caloric value. Reishi addition improved bread yield and reduced baking losses, enhancing production efficiency. However, higher Reishi levels negatively impacted bread volume, possibly due to interference with gluten network formation. An increase in crumb moisture was observed, contributing to extended freshness. Sensory evaluation revealed that loaves of bread containing up to 6% Reishi were acceptable to consumers, whereas higher levels detrimentally affected flavour and aroma. Therefore, Reishi-enriched bread, particularly with 6% supplementation, presents a promising functional alternative to conventional wheat bread, optimising nutritional benefits while maintaining consumer acceptability.

Study of the jellyfish Rhizostoma pulmo hydrolysis and characterization of the obtained product

The purpose of this work is to develop technological parameters for the hydrolysis of barrel jellyfish Rhizostoma pulmo involving the use of enzymatic agents «Enzy-mix» and alcalase, available through the domestic market, as well as to investigate the amino acid and mineral composition of the resultant hydrolysate.Methods used: the process of hydrolysis has been assessed based on the changes in peptide concentrations in the hydrolysate, the content of amino nitrogen, and the degree of hydrolysis. To investigate its chemical, amino acid, and mineral composition, the standard methods were used. Novelty: the use of jellyfish for hydrolysis after its thawing and the hydrolysis procedure not involving the addition of water into the raw material subjected to hydrolysis present a novel approach.Result: the optimal regime for hydrolysis of barrel jellyfish Rh. pulmo after its thawing has been identified, which was characterized by the use of 1% alcalase at the temperature 55±2 °C and duration of 1 h. It has been shown that alcalase is more effective in terms of amino nitrogen accumulation than enzymatic agent «Enzy-mix». The values of amino nitrogen after 1 h of hydrolysis involving the use of 1% alcalase were higher than the values of the same parameter obtained during the 3-hour hydrolysis involving 1.5% «Enzy-mix» at the temperature 40±2 °C. The hydrolysate, after its concentration to the dry matter exceeding 30%, contains no less than 15.1±0.59% of protein represented by 48% of essential amino acids, out of which leucine and isoleucine prevail (15 %). Among non-essential amino acids, the most prominent was glycine (17 %). For all essential amino acids, except for valine, the amino acid score exceeds 100%. In humans, consumption of around 20 g of the hydrolysate covers the daily physiological requirement of magnesium.Practical significance: the obtained data on the amino acid profile and mineral composition of the barrel jellyfish Rh. pulmo hydrolysate provide the basis for its consideration as a promising ingredient for the functional nutrition products.

SCIENTIFICLY BASED CALCULATION METHODS AND EXPERIMENTAL DATA BASES FOR THE PREVENTION OF PREMIUM FIRE EXPLOSIONS AND UNSAFE EXPLOSIONS OF PYROTECHNIC MULTICOMPONENT NITRATE-METALLIZED MIXTURES UNDER EXTERNAL THERMAL

Problem statement. Methods of preventing the occurrence of forced fire-hazardous destruction of products in the event of exposure to external thermal actions are of great practical importance. At the same time, they should be based on scientifically based methods for determining the critical values of parameters of thermal effects on products and technological parameters of mixture charges, the excess of which leads to premature fire-hazardous destruction of products. To develop such methods, it is necessary to have the results of theoretical and experimental studies of the processes of heating the shells of mixture charges for various external heat flows and their thermoreaction times, as well as the processes of ignition and development of their combustion under different external conditions. Purpose of the article. To form the results of theoretical studies in the form of scientifically based methods that allow preventing and controlling the premature ignition of mixture charges, the explosive development of their combustion process and the fire-hazardous destruction of products under conditions of external thermal effects, as well as the compilation of the results of experimental studies into a single database with determination of the influence of the technological parameters of the mixtures on the characteristics of their ignition processes and the development of combustion, the use of which allows reducing the number of fire-explosive destruction of products in conditions of elevated heating temperatures and external pressures. Conclusion. Scientifically based methods of determining the critical values of the parameters of external thermal actions for the quantitative assessment of the level of fire safety of pyrotechnic products based on multi-component nitrate-metallized mixtures have been developed. A scientific and technical base of experimental data was created to determine the regularities of the influence of a wide class of technological parameters of mixtures on the main characteristics of the processes of ignition and development of combustion of mixtures (ignition temperature, induction time, speed of combustion development) under conditions of external thermal actions (elevated heating temperatures, external pressures, etc.), which makes it possible to determine the probability of fires occurring at facilities where products are stored.

Economic and Environmental Aspects of Applying the Regeneration of Spent Moulding Sand

This article presents issues related to the rational management of foundry sand in the context of sustainable development. Attention was drawn to the need to take appropriate measures to protect available natural deposits of good foundry sands in terms of their depletion. The main objective of the analyses undertaken was to find out whether more expensive but more efficient thermal regeneration can compensate for the higher energy consumption in relation to mechanical regeneration of spent moulding sand with an organic binder. This aspect was considered from the point of view of the multiple operations performed to clean the grain matrix from the spent binder, taking into account the direct and indirect costs of the process. This paper presents a comparative analysis of the mechanical and thermal regeneration of spent moulding sand on equipment offered by an exemplary manufacturer. Attention was drawn to the successively increasing price of the regeneration process. When analysing the grain matrix recovery process for sustainability reasons, attention was drawn to an important factor in grain matrix management related to its yield in different regeneration methods. Based on an analysis of the costs of regenerating 1 tonne of spent moulding sand, it was concluded that, in the long term, thermal regeneration, which is more expensive due to the cost of equipment and energy consumption, can offset the outlay incurred. Sand consumption was found to be 4.6 times higher by mechanical regeneration in the case studied. At the same time, the grain matrix after thermal regeneration was found to have significantly better and more stable technological parameters in subsequent sand mould preparation cycles. The reproducibility and stability of the technological process can also be an important component of economic growth as part of sustainable development.

DEVELOPMENT OF INNOVATIVE TECHNOLOGY AND HARDENING EQUIPMENT FOR THE IMPLEMENTATION OF HARDENING HEAT TREATMENT OF METAL PRODUCTS USING FLUIDIZED BULK MATERIALS (PART 1)

Statement of the problem. One of the main problems faced by a modern enterprise is the search for ways to improve the efficiency of its activities. For the effective functioning of the thermal units of toolmaking industries, the simultaneous availability of heating and quenching devices with different heating and cooling media is required. This explains the desire of manufacturers and scientists to find technological, cheap, environmentally friendly heating and cooling media that can provide the required heat treatment parameters and high quality of the processed parts. The purpose of the article is to analyze the state-of-the-art of hardening thermal (combined) treatment methods using bulk materials as media for volumetric heating and forced cooling of metal products and the design and technological features of hardening devices that can ensure a rational structural state of metal parts of complex geometric shapes with a minimum level of their warping and deformation on the example of using vibro-fluidized bulk materials (in the technical literature, the term vibro-gravity particles of heat is used). Research results. To analyze the results of tests of bulk materials as quenching media for high-alloy steel grades and their effect on the structure and properties of the metal in comparison with the traditional oil quenching regime. To consider the features of quenching devices that use mechanical vibration to produce vibro-s bulk material and the possibility of their use in the implementation of quenching modes (including isothermal) of steel products of complex geometric shapes. Conclusion. The use of fluidized bulk materials in industry as media for volumetric heating and hardening of metal products and the design of devices for their use has been investigated. The advantages of the fluidized bed cooling method for the effective implementation of hardening heat treatment regimes are determined. It is shown that this method of forced volumetric cooling of toolmaking products is rational in terms of various indicators. The structural and technological parameters of devices for its implementation are analyzed, which can consistently provide the required level of properties of alloyed and high-alloy tool steels with a minimum level of warping and deformation.

Effect of HVOF method spraying parameters on phase composition and mechanical and tribological properties of 86WC-10Co-4Cr coating

Valve components used in the petroleum industry are subjected to intense wear during operation, which leads to a sharp decrease in their durability. Usually, the often subjected to the wear process surface of the valves is treated by tungsten carbide cladding to improve its durability. Because of the difficulty in applying tungsten carbide using conventional surfacing techniques, high velocity oxyfuel (HVOF) spraying technology is rec- ommended. In this work, the mechanical, tribological properties and phase composition of 86WC-10Co-4Cr composition coatings obtained by HVOF Termika-3 high-velocity gas-fuel spraying were investigated. Vary- ing the technological parameters of spraying was carried out by changing the spraying distance, which led to differences in the thickness of the coatings. The phase composition, microstructure and distribution of ele- ments were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM) methods. The hardness of the samples was measured on a microhardness tester using the Vickers method, the friction coef- ficient and the wear rate were investigated using a friction and wear tester. It was determined that the surface of the coatings had developed character and high roughness. The results of X-ray phase analysis showed the predominance of hexagonal WC as the major phase, with a small amount of hexagonal tungsten carbide W2C as the minor phase, and the minor presence of cobalt oxide CoO. It was found that the increased wear re- sistance and low friction coefficient of 86WC-10Co-4Cr coatings are explained by the high volume fraction of hard and stable WC grains with high resistance to wear.

Analysis of Copper Welding Parameters during the Manufacture of Tubular Profiles Using Unconventional Extrusion Processes.

In recent years, there has been a lack of information in the literature regarding the extrusion and connection of closed profiles from oxygen-free copper in bridge dies. Available studies contain information on the processes of extrusion and connection of profiles from aluminium alloys and various types of steel. However, there is a lack of detailed data on the values of technological parameters for which copper is joined in the extrusion process. Therefore, one of the goals of this work is to fill the gap in the literature regarding the extrusion of oxygen-free copper in bridge dies. In this work, the authors determined the thermo-mechanical conditions at which oxygen-free copper will be joined. This paper describes the effects of charge temperature and hydrostatic pressure in the weld zone of a bridge die on copper bonding in the fabrication of tubular profiles. Physical tests of the welding process under the conditions of upsetting a material consisting of two parts were carried out using the Gleeble 3800 metallurgical process simulator with the PocketJaw module in the standard configuration for SICO (strain-induced crack opening) tests. For the numerical simulations, the commercial computer programme FORGE®NxT 2.1. using the finite element method (FEM) was used. Based on the analysis of the test results obtained, it was found that complete material bonding during the extrusion process could be achieved for a charge temperature higher than 600 °C and a hydrostatic pressure of 45-65 MPa.

STRUCTURE OF THE AUTOMATED CONTROL SYSTEM OF TECHNOLOGICAL PARAMETERS OF TREATMENT FACILITIES OF THE CITY SEMEY

Increasing the efficiency of control of treatment facilities can be achieved by automation of control at the stages of observation, collection, processing and analysis of information by means of mathematical data analysis packages, implementation of automated control systems of technological processes.This article is devoted to the issues of technical modernization of automatic control system of water disposal in Semey city. The need to modernize the concept of building the ACS has arisen in connection with the technical re-equipment of production and introduction of new energy-saving technologies in it.The hypothesis of the research suggests the possibility of improving the efficiency of wastewater treatment facilities of Semey city through the use of modern methods of collection and transmission of technological parameters to the control panel of the dispatcher in order to make operational decisions on the management of technological and technological process of wastewater treatment based on monitoring of equipment operation. Due to the complexity of the whole complex of treatment facilities, the main sewage pumping station (GKNS-2) and air blower pumping station (ABPS) were selected as objects for the development of automated control system of technological parameters (ACS TP).The article considers the proposed structural scheme of the automated system of control of technological parameters of treatment facilities of Semey city, gives a description of each level of the system and the principle of their interaction.

Monitoring the thermal state of an ingot with beveled and rounded corners in a slab crystallizer of a CCM

The organization of ingot cooling in the continuous caster mold affects the reliability, productivity and quality of the resulting ingots. Insufficient heat exchange between the solidifying metal and the wall of the mold leads to a decrease in the thickness of the solid shell of the ingot, which causes the formation of surface defects, and when the ingot is pulled out of the mold, emergency breakthroughs occur. Excessive heat transfer leads to an increase in the thickness of the solid shell, which entails excessive shrinkage of the ingot surface with the formation of a gap between the solid shell of the ingot and the walls of the mold. The appearance of an air gap leads to increased wear of the copper walls of the mold. There is a design of copper walls that makes it possible to reduce the normal component of forces that occurs during wear, reduce the temperature gradient and stress concentration in the corner of the ingot, and also bring the thickness of the hard crust stocking in the corner closer to the perimeter of the mold. However, the thermal state of the formed ingot with such a crystallizer design remains poorly understood. The goal of the work is to create a virtual tool for monitoring the operation of the mold of a slab continuous caster based on the development of a mathematical and computer model of the thermal state of an ingot with beveled and rounded corners. The temperature distribution in the ingot was calculated using the quasi-equilibrium theory of solidification. The numerical implementation of the mathematical model and obtaining an approximate solution using a computer were carried out using the finite dif-ference method and an implicit difference scheme. A computer program was developed in the Matlab development environment. Using computer modeling, the temperature distribution over the volume of the slab at the outlet of the mold with beveled and rounded corners was obtained. The program for the selected mold design allows you to analyze the solidification of the ingot skin and monitor this process for the selected steel grade and specified casting technological parameters

Study of the features of concentration inhomogeneities during the on ground-based processing of the space experiment of the Ge(Ga) crystals growth

The article presents the results of the preparation and ground testing of the space experiment for growing Ge (Ga) crystals, planned on board the multifunctional laboratory module as part of the ISS RS. Under the conditions simulating microgravity, the features of the formation of concentration inhomogeneity in the form of growth bands when growing crystals under various thermal conditions (in the presence or absence of a free melt surface (Marangoni convection)), as well as when changing technological parameters (variations in growth rate) were investigated. Based on the obtained results of metallographic and electrophysical studies, conclusions were made about the peculiarities of the influence of the technological parameters of the crystallization process on the structural perfection of the grown crystals under microgravity conditions

Lipidomic Profiling and Storage-Induced Changes in Cassava Flour Using LC-MS/MS.

Cassava serves as a primary staple food for over one billion people worldwide. The quality of cassava flour is markedly affected by the oxidation and deterioration of lipids during storage. Despite its significance, the lipid composition of cassava flour and its alterations throughout storage periods have not been extensively studied. This study offers a comprehensive lipidomic analysis of cassava flour over storage periods using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). The results showed that 545 lipids from five classes and 27 subclasses were identified in cassava flour, including key substances such as free fatty acids (36 species), diglycerides (DGs) (31 species), and triglycerides (TGs) (259 species). Using Metware Cloud for statistical analysis, significant variations were observed in 50 lipid species over long-term storage, reflecting changes in lipid profiles due to storage. These lipids correlate with seven metabolic pathways, among which glycerolipid metabolism is the most affected. The metabolites associated with these pathways can differentiate cassava flour based on the length of storage. This study provides a theoretical basis and storage technology parameters for lipid changes during cassava flour storage.

Valorization of Strawberry Tree Berries and Beeswax from Montesinho Natural Park for Cosmetic Industry-A Case Study Formulation.

Consumers are increasingly concerned about cosmetic ingredients' origin, looking more than ever to sustainable and greener formulations. The Natural Park of Montesinho, located in Portugal, is characterized by an enormous fauna and flora diversity. Among them, beeswax and strawberry trees (Arbutus unedo) have attracted the cosmetic researchers' interest due to their bioactive compounds' richness, particularly fatty acids and phenolic compounds. The main goal of this study was to develop an innovative cosmetic product with antioxidant properties composed by both matrices. Briefly, samples were obtained in the Natural Park of Montesinho in October 2022. Beeswax was analysed for lipid profile and contaminants, while extracts were obtained from fruits by ultrasound-assisted extraction (UAE) using water as a solvent. The effect of extraction time (15-90 min) was studied on the total phenolic content (TPC), in vitro antioxidant/antiradical activity, and reactive oxygen species (ROS) scavenging capacity. The beeswax lipid profile presented a high incidence of palmitic, oleic, and linoleic acids. The extract obtained at 60 min presented the highest TPC (30.27 mg GAE/g dw) and antioxidant/antiradical activities (ABTS = 30.36 mg AAE/g dw; DPPH = 43.83 mg TE/g dw; FRAP = 415.61 µmol FSE/g dw). An IC50 of 19.78 µg/mL was achieved for the hypochlorous acid, while for superoxide radical and peroxyl radical the IC50 were, respectively, 90.51 µg/mL and 0.19 µmol TE/mg dw. The phytochemical profile revealed a high content of gallic acid, and catechin and its derivatives. The hydrophilic cream developed revealed ideal technological parameters, particularly its stability.

Development and verification of a multi-component model for steam methane reforming

RELEVANCE. Steam methane reforming is the dominant method of hydrogen production. Its significant share in global CO2 emissions highlights the importance of optimizing technological parameters to reduce environmental impact. The developed multi-component model of steam methane reforming in COMSOL Multiphysics is relevant not only due to its applicability for optimizing existing production facilities but also for its potential in developing new methods for utilizing associated petroleum gas. In the context of import substitution in the hydrogen energy sector, this model is also of interest, allowing for the calculation of technological parameters of industrial installations.THE PURPOSE. The aim of the work is to develop and verify a multi-component model of steam methane reforming.METHODS. The research methodology includes the use of experimental data from the literature and industrial indicators for integration into a multi-component model in COMSOL Multiphysics. This enables the modelling of complex chemical interactions under conditions characteristic of the industrial steam methane reforming process.RESULTS. The developed multi-component model allows calculating key parameters of the steam methane reforming process, including the concentration of components (methane, hydrogen, carbon monoxide, and carbon dioxide) and temperature along the reactor. The model successfully describes the chemical interactions between components and takes into account the influence of operating conditions, such as temperature, pressure, and steam/gas ratio, on process efficiency. The model verification was carried out by comparing the modelling results with experimental data and indicators of real industrial processes. Their correspondence confirms the high degree of reliability and suitability of the model for practical application in engineering calculations and optimization of steam methane reforming processes.CONCLUSION. The conclusions made based on the modelling can be used for further improvement of methane conversion technologies, contributing to their efficiency and environmental friendliness. There is also potential for using the model to calculate the stages of installations for the utilization of products from the processing of associated petroleum gas.

Choosing the optimal technology for obtaining Crocus alatavicus extract with a high content of flavonoids and carotenoids

In recent years, there has been a significant increase in demand for herbal medicines, due to the growing interest of consumers in natural and safe alternatives to synthetic medicines. In response to these trends, manufacturers are focusing on developing new formulas and extraction technologies to meet the increased demand for herbal medicines. Modern extraction methods make it possible to efficiently extract secondary metabolites from plant raw materials, maintaining an almost complete chemical composition and ensuring a high yield of extractives. The possibility of regulating the concentration of extracted biologically active substances during the process opens up new prospects for the use of plant raw materials as basic pharmaceutical substances. It was found that all the studied plant species of the genus Crocus L. demonstrate antioxidant, anti-inflammatory and cardioprotective activity. Crocus alatavicus, which is a representative of the flora of Kazakhstan, is of particular interest. The purpose of this study is to select the optimal extraction method for obtaining extracts with the maximum content of flavonoids and carotenoids from the aboveground part of Crocus alatavicus. The study of the technological parameters of obtaining an extract from this plant active substance is of practical importance for the further development of medicines and the formation of a scientific justification for their use.

Effect of underwater friction stir welding parameters on AA5754 alloy joints: experimental studies

The water as a welding environment may generate serious technological and metallurgical problems but in certain cases, the physicochemical properties of water can be used effectively, e.g., to impart the specific properties of welded materials. The purpose of the work was verification of effectiveness of the water cooling of aluminium alloy AA5754 for various sets of technological parameters of underwater friction stir welding (UFSW). For the joints performed with the range of parameters of rotational speed: 475–925 rpm and welding speed: 47.5–95 mm/min, the following examinations were carried out: visual tests, radiographic tests, static tensile test, fractography (SEM, scanning electron microscope) analysis, and surface texture analysis performed with 3D measurement system. All of the joints were characterized with some amount of flash. Besides, depending on the values of selected parameters, the defects arising from inadequate stirring were found—tunnel defects and melting. The best appearance of the joint was obtained for the set of parameters of 925 rpm and 47.5 mm/min. The samples of the same joint were found to be of the highest mechanical properties—ultimate tensile strength (UTS) of 194 MPa and elongation (A) of 9.2%. The results were confirmed by the fractography analysis, which in this case indicated the ductile fracture mode. Dynamic plastic behaviour strongly depends on the process parameter values, which was reflected in the results of surface texture analysis. The parameter selection resulted in significant changes in the roughness results (from 8 to 14.2 µm depending on the sample) as well as the flow ring distance of the weld (from 20 to 50 µm depending on the sample).

Modeling the influence of technological parameters of the magnetron sputtering process using the Caroline D12C system on the proportion of nanocrystallites in the structure of thin silicon films

Modeling the influence of technological parameters of the magnetron sputtering process using the Caroline D12C system on the proportion of nanocrystallites in the structure of thin silicon films