Due to the high level of disability and death caused by heart diseases worldwide, the problem of combating cardiovascular diseases is becoming more and more important and relevant. In fact, one of the leading causes of death worldwide has long been cardiovascular disease, according to the World Health Organization. Among heart diseases, the most dangerous to life is myocardial infarction. In connection with the rapid morbidity, early diagnosis of this disease is one of the topical problems of modern public health care. At present, although there is a wide range of different statistical, math methods and computer tools for the processing of cardiological information, the task of increasing the accuracy of methods for the analysis of electrocardiograms and diagnostic tools in this field of study remained relevant. Taking into account the imperfect tools and systems for diagnosing heart diseases, as well as the human factor, the lack of a method that can help doctors to diagnose myocardial infarction early requires the development of new diagnostic information methods. This article presents a neural network analysis methodology for diagnosing myocardial infarction based on the joint analysis of direct and reverse signs of myocardial infarction from electrocardiographic information obtained from a portable cardiac analyzer.

Stressful events in students' and teachers' personal, academic, and professional lives are widespread. The paper discusses many effective methods and techniques for correcting and preventing stress that are simple to learn and practice. They give good results in working with children, adolescents, and youths in training and education. Some practices are more complex and require more attention and effort to understand and master them, but they also have broader capabilities in various situations. Therefore, training sessions aimed at training in the prevention and correction of (di)stress conditions are very relevant and necessary. The results showed that there is a conscious and urgent need for students to reduce anxiety and stress, including ways to deal with learning stresses. Stress management can and should be structured and systematically organized, including in the instrumental sense: students need to be taught how to manage stress and themselves, increase their resistance to stress (resilience), and be trained to use different coping techniques with anxiety, as appropriate. In an empirical study, representatives of other groups of students from three Kazakh universities answered questions from three author's stress questionnaires. According to the respondents, the study results showed that students need knowledge about stress. The study showed the urgent need for special educational and training seminars, lectures, and even courses on (di)stress and physical, mental, and moral injuries and coping with them. Such classes are needed to help schoolchildren and students cope with stress and avoid problems with moral, mental, and physical health to prevent other negative consequences of school and related strains. © 2023 by the author.

In this study, a new design of a hydroturbine was developed, modelled, and constructed. The unique features of this turbine design required a thorough investigation and optimization process to enhance hydroturbine performance. The paper discusses numerical and experimental results obtained on the hydroturbine. The optimal angle of attack for the inlet flow direction has been computed from numerical modelling. Consequently, data on velocity, pressure, lift, and drag forces along the blade have been obtained. The study also takes into account the operation of the hydroturbine under non-rotating and rotating rotor modes. Performance metrics such as head, torque, hydraulic power, hydroturbine power, and efficiency were then calculated based on water discharge. These performance calculations were conducted using COMSOL Multiphysics, employing Direct Numerical Simulation and k-epsilon methods. Numerical calculations offer a cost-effective approach to reducing the financial burden associated with material costs for manufacturing hydroturbine prototypes.

The article presents an innovative approach to the restoration and stabilization of weak soils, using the example of the Turkestan region, characterized by an arid climate and degraded soil cover. The main goal of the study was to develop and experimentally validate a biostabilization technology aimed at improving the physico-chemical and engineering-geological properties of soils through environmentally safe compositions. This technology addresses challenges such as erosion, low bearing capacity, and land degradation, which are especially critical in arid regions. The research involved an engineering-geological analysis of soils using laboratory and computational methods. Evaluated parameters included humus content, mobile phosphorus, nitrogen, exchangeable bases, water retention, and resistance to erosion. Experimental results showed that vermicompost significantly improves soil structure and geotechnical stability. Potassium polyacrylamide enhances water retention, reducing the risk of deformation and settlement. Lime-sulfur broth strengthens surface horizons and reduces wind erosion, although its impact on mechanical properties requires further study. The proposed biostabilization methods effectively improve the geotechnical characteristics of weak soils, increasing their resistance to erosion and enhancing their suitability for engineering applications such as foundation stabilization, slope reinforcement, and land restoration. These technologies are especially relevant in arid climates, where soil degradation is widespread. The study's findings can be applied in geotechnical engineering, engineering geology, and sustainable agriculture to support environmentally responsible land use and the restoration of degraded areas.

Hexavalent chromium Cr (VI) compounds present in ilmenite concentrate not only pose significant environmental hazards due to their toxicity but also complicate further processing, interfering with technological operations in industrial production. The high chromium content in ilmenite concentrates hinders their conversion into titanium-containing slag, necessitating the removal of chromium ions to permissible residual levels to produce titanium dioxide. In this study, various sorbents were investigated for the removal of chromate ions from the industrial effluents generated during ilmenite concentrate processing. The sorbents examined included natural and modified diatomite, activated carbon, taurite (shungite), and the ion-exchange resin Lewatit M500. The structures of both natural and modified diatomite were analyzed using scanning electron microscopy (SEM). It was determined that natural diatomite samples consist of diatom frustules of various shapes and their fragments, with structural element sizes ranging from submicron dimensions to 50 µm. A mathematical analysis of the sorption data for hexavalent chromium ion removal from solutions was performed. The results demonstrated high sorption efficiencies for Lewatit M500 (98.34%) and diatomite modified with iron compounds (98.95%). The findings suggest that diatomite is a promising sorbent for chromate ion removal from wastewater due to its availability and potential for chemical modification.

Microfluidic organs-on-chips or microphysiological systems (MPS) are promising tools that can potentially replace animal testing in drug development. MPS are platforms with microchannels seeded with certain organ cells used to emulate in vivo environments in laboratory conditions. Among them, platforms seeded with lung cells called lung-on-chip devices can evaluate the influence of toxic particles, gases, and chemicals on lung tissue in vitro. Lung-on-chip devices allow the mimicry of healthy lung conditions and a wide range of diseases (asthma, cancer, autoimmune, infections). This review focuses on the use of electrospun nanofiber membranes as a functional basement membrane which plays a central role in the development of lung-on-a-chip platforms. Here, we briefly introduce microfluidic devices, MPS, and lung-on-chip devices. Existing basement membrane models, such as thin-film and gel-based membranes, and their challenges/disadvantages are discussed. Next, the concepts of electrospinning and nanofiber membranes are introduced. Finally, the nanofiber membranes used in lung-on-chip devices are reviewed. Implementation of different polymer materials used to synthesize the nanofiber membranes and different methods for incorporation of the membrane inside the device are discussed. Electrospun nanofiber membranes provide good mechanical properties, allow transmigration of the immune cells, and withstand the physiological strain without affecting the cell viability.

This study describes both experimental and numerical investigations into the heat and mass transfer processes governing the vacuum freeze drying of camel milk, with a specific focus on improving the energy efficiency. A three-dimensional model was developed and solved using the finite element method to simulate temperature evolution and sublimation interface progression during drying. The numerical model was validated against experimental data, achieving strong agreement, with an 𝑅2 value of 0.94. A detailed parametric analysis examined the effects of the shelf temperature, sample thickness, and chamber pressure on the drying kinetics and energy input. The results indicate that optimising these parameters can significantly reduce the energy consumption and processing time while maintaining product quality. Notably, reducing the sample thickness to 4 mm shortened the drying time by up to 40% and reduced the specific energy consumption (SEC) from 358 to 149 kWh/kg. These findings offer valuable insights for the design of more energy-efficient freeze drying systems, with implications for sustainable milk powder production and industrial-scale process optimisation.

Proton exchange membranes (PEMs) play a critical role in various energy conversion devices, such as fuel cells. Developing advanced PEMs with improved hydronium ion transportation and chemical stability is essential for enhancing the performance and durability of these devices. In this research project, we focus on the development and molecular modeling study of a novel composite material based on poly(acrylic acid) and graphene oxide for application as a high-performance proton exchange membrane. The need for better PEMs has led us to explore the potential of combining poly(acrylic acid) and graphene oxide, as both materials offer unique advantages in terms of proton conductivity and mechanical strength. Our goal is to investigate how these two components interact and synergize to enhance the overall performance of the PEM, particularly in challenging operating conditions. To achieve this, classical all-atom Molecular Dynamics (MD) simulations using Gromacs software were employed. The simulations allowed us to study the formation mechanism of the poly(acrylic acid) and graphene oxide composite material and its application in facilitating hydronium ion transportation within the PEM. Our simulation results revealed fascinating insights into the composite material's behavior. Notably, we observed the emergence of new interactions between poly(acrylate) oligomers and graphene oxide layers, evident from the analysis of interaction energy values. These interactions contribute to the material's enhanced transport properties, making it promising for PEM applications. Moreover, we assessed the mobility of hydronium ions in the graphene oxide and polyacrylate nanocomposite-based PEM and found it comparable to the mobility in traditional poly(acrylate)-based PEMs. This indicates that the introduction of graphene oxide provide compatible proton transport efficiency and renders the composite suitable for practical application in PEM devices. In conclusion, our study demonstrates the potential of the poly(acrylic acid) and graphene oxide composite as a high-performance proton exchange membrane.

This article addresses the optimization of start-up modes for technological machines with heavy rotors, relevant across industries, including mining and metallurgy. It proposes a pneumatic starting and auxiliary device (PSAD) using bellows pneumatic cylinders and a ratchet mechanism to facilitate start-up and reduce inrush currents in such machines. Materials and methods. An experimental setup simulating a ball mill’s operation was designed. The methodology involved investigating the impact of the limit switch position, which controls the main engine, on the inrush current value. The experiment then fixed this position and altered the pneumatic system pressure in 0.1 MPa increments, from 0.1 MPa to 0.4 MPa, recording the resulting inrush current changes. Results. The study shows the impact from pulse and follow-up current to motor terminals, and the pre-work of PSAD in step-by-step mode. The result showed significant reduction in the initial current peaks due to the starting process of the main engine. The optimal limit switch position was at the beginning of the stroke of one cylinder, providing maximum force at minimal deformation. Increasing pressure led to inrush current decreases. Discussion. These results affirm pneumatic power systems and implementation in starting equipment, but there are complexities with precise adjustment and the requirement for good manufacturing and assembling qualities. These additional findings provide a more detailed evaluation of factors influencing PSAD performance. In particular, selecting the ideal diameter for supply piping is crucial. Conclusion. PSAD using bellows pneumatic cylinders and a ratchet mechanism is a promising approach for heavy rotor machines. Tests displayed efficiency in reducing inrush currents. Pre-work in step-by-step mode, combined with pressure increase, lowers starter loads on the drive. Precise adjustment is critical, otherwise, system performance and reverse drum rotation will result. Resume. This research establishes optimal PSAD parameters (limit switch placement, pneumatic pressure) for minimal inrush current. Results aid PSAD implementation in mining/metallurgy, enhancing reliability, energy efficiency, and decreasing costs. Still, deployment should consider adjusting difficulties and needs of producing and meeting components.

In this article, composite binders based on industrial waste—phosphogypsum, granular phosphoric slag, and burnt barium carbonate tailings––are investigated. It was found that the optimal composition (65% slag, 20% phosphogypsum, 15% tailings) provides compressive strength up to 31.1 MPa after steaming, which corresponds to grade M300 cement. Replacing natural gypsum with phosphogypsum increases strength by 5–10%, and using waste reduces cost by 20–25% compared to traditional binders. This technology eliminates the need for high-temperature firing, reducing energy consumption by 40–50%. Neutralization of harmful impurities of phosphogypsum with oxides of MgO and CaO reduces the ecotoxicity of the material by 70–80%. It is shown that hydrothermal treatment accelerates hardening, providing 90% of brand strength in 28 days. The developed binders are promising for the production of building blocks, road surfaces, and land reclamation.