The optimal ratios of the components of the WC–Co‒CrB2 system have been established, at which a finely dispersed structure is formed with a simultaneous improvement in physical and mechanical properties. It is shown that the introduction of CrB2 (in concentration CCrB2 = 4% wt) leads to a twofold increase in fracture toughness (from KIc = 4.4 MPa ∙ m1/2 to KIc = 9.8 MPa ∙ m1/2) with a slight decrease hardness (from H = 15.1 to 13.9 GPa), as well as to an increase in the ultimate bending (from σ = 2000 to 2500 MPa) and compression (from σ = 5300 to 6000 MPa) strength of sintered composite specimens. Creation of the WC–Co‒CrB2 composite materials with improved mechanical and operational properties is essential for optimizing the designs of drilling tools for various technological purposes, increasing their reliability, energy saving, and improving operational properties. © 2022 «OilGasScientificResearchProject» Institute. All rights reserved.
The industrial waste can cause significant harm to human health and to the environment. Organic dyes in particular are environmentally dangerous since they may cause the death of aquatic life or contaminate the feed chain. Thus, one of the current research fields consists of the development of an inexpensive and environmentally friendly method to purify wastewater from organic contaminants. Among the others, Zinc oxide (ZnO) is considered one of the most effective photocatalysts for the decomposition of organic pollutants in water. In this work, we developed a highly efficient low-temperature and environmentally safe synthesis method to obtain photocatalytically active nanostructured ZnO by chemical precipitation from a solution. The effect of the technological conditions of synthesis on the photocatalytic properties is considered in detail, the correlation with the morphology, structural, and optical properties of the synthesized ZnO samples is determined. It was found that the maximum photocatalytic activity with respect to the decomposition of the dye rhodamine-B (RhB) is achieved for samples synthesized at NaOH molar concentration from 0.4 to 0.7 M; in this case, the sizes of crystallites along the crystallographic direction 002 reach maximum values of ∼42 nm. On the contrary, the sizes of crystallites along the directions 100 and 101 decrease monotonically from 30 to 25 nm with an increase in the molar concentration of NaOH from 0.14 to 1 M. Copyright © 2022 Kedruk, Baigarinova, Gritsenko, Cicero and Abdullin.
Pervaporative desulfurization is a potential method for removing sulfur compounds from liquid hydrocarbon streams, having many advantages over existing methods. This overview covers the fundamentals, recent breakthroughs, and different applications of pervaporative desulfurization. The paper begins by explaining pervaporative desulfurization's core concepts, focusing on how polymeric membranes selectively separate sulfur molecules from liquid hydrocarbons. It explores membrane properties, operating conditions, and feed composition in pervaporative separation. It highlights how pervaporative desulfurization may reduce sulfur content to ultra-low levels and meet strict environmental and fuel quality standards. Finally, this comprehensive review paper concludes with a discussion on the future prospects and research directions in the field of pervaporative desulfurization. It highlights the need for continued innovation in membrane materials, module design, and process optimization, as well as the importance of addressing challenges related to scale-up and industrial implementation. Overall, this review paper provides valuable insights into the advancements, challenges, and potential applications of pervaporative desulfurization, offering a comprehensive understanding of this technology for researchers, engineers, and all parties involved in the development and implementation of sustainable sulfur removal processes. © 2023 The Authors. This is an open access article under the CC BY-NC-ND license.
The number of patients with cardiovascular diseases (CVD) is rapidly increasing in the world. Many CVDs are likely to manifest their symptoms some time prior to the onset of any adverse or catastrophic events, and early detection of cardiac abnormalities is incredibly important. To reduce the risks of life-threatening arrhythmia, it is necessary to develop and introduce portable systems for monitoring the state of the heart in conditions of free activity. This paper presents the second generation (prototype) of a portable cardiac analyzer and the developed system for non-invasive cardiac diagnostics. The portable cardiac analyzer mainly consists of an ADC for taking an electrocardiosignal (ECS) and an STM32L151xD microcontroller. To record operational data on current ECS, a block of non-volatile high-speed memory MRAM is connected to the microcontroller. A communication unit is based on the universal combo module SIM868 from SIMCOM, which supports data exchange in GSM/GPRS networks. The developed ECG monitoring system allows making decisions at different levels (cardiac analyzer, server, doctor), as well as exchanging information necessary to ensure an effective diagnostic and treatment process. We evaluated the performances of the developed system. The signal-to-noise ratio of the output signal is favorable, and all the features needed for a clinical evaluation (P waves, QRS complexes and T waves) are clearly readable. © 2022. All Rights Reserved.
Discrete and continuous models of the spread of the epidemic are considered, taking into account vaccination and limited time spent in groups. Conducted qualitative and quantitative proposed models. The influence of process parameters is investigated. As an example, the spread of the COVID-19 epidemic in Kazakhstan is being studied. © 2024, Jomard Publishing. All rights reserved.
The convergence of adsorption and photocatalysis in hybrid composites offers a sustainable and energy-efficient strategy for the removal of persistent organic pollutants from water systems. This review presents a comprehensive analysis of recent advances in adsorption–photocatalysis hybrid materials, focusing on the synergistic mechanisms that enhance pollutant capture, photodegradation, and material regeneration. We classify and evaluate three major categories of composites: carbon-based, metal oxide, and polymeric materials, highlighting their physicochemical characteristics, surface morphologies, and functional architectures. Special attention is given to Z-scheme and type II heterojunctions, plasmonic enhancements, and nanoscale engineering that improve solar light harvesting and charge carrier dynamics. The influence of key environmental parameters such as pH, light intensity, and contaminant load is discussed, along with strategies for material optimization and recyclability. Unlike conventional reviews, this work offers a design-focused and environmentally integrated perspective, emphasizing scalable, low-waste, and sunlight-driven solutions for water purification. The insights provided here aim to guide future research on hybrid systems that contribute to the circular economy and renewable energy-based remediation technologies. © The Author(s) 2025.
One of the promising intermetallic compounds for use in nuclear and fusion reactors, as well as in hydrogen energy technology, are intermetallic compounds of beryllium with metals such as Ti, V, Zr and Nb. Beryllium-based intermetallics are not only a promising material for blankets of future fusion reactors, but can also be utilized in other areas of the nuclear industry, including fission reactor reflectors, rocket and space technology. The interest in studies of the interaction of hydrogen isotopes with beryllides is related to the accumulation of tritium and helium in the material, formed as a result of nuclear reactions under neutron irradiation, and is caused by the need for understanding the processes arising from such interaction. In this work, hydrogen sorption and desorption processes of zirconium beryllide ZrBe2 produced by industrial technologies at JSC “Ulba Metallurgical Plant” (JSC UMP) were investigated. The experiments were performed by the Sievert's and thermal desorption spectrometry (TDS) methods. In TDS experiments deuterium was chosen for samples saturation to reduce the possible error in determining fluxes associated with the release of hydrogen from the elements of the vacuum chamber. An equation for hydrogen solubility in zirconium beryllide ZrBe2 was obtained by processing the experimental data obtained by the Sievert's method: [Formula presented] The temperature intervals of formation and decomposition of two different hydride phases (deuterides) of zirconium beryllide ZrBe2 at ∼ 600 K and ∼ 900 K have been established in TDS experiments. © 2024 The Authors
Ensuring the best quality and performance of modern speech technologies, today, is possible based on the widespread use of machine learning methods. The idea of this project is to study and implement an end-to-end system of automatic speech recognition using machine learning methods, as well as to develop new mathematical models and algorithms for solving the problem of automatic speech recognition for agglutinative (Turkic) languages. Many research papers have shown that deep learning methods make it easier to train automatic speech recognition systems that use an end to end approach. This method can also train an automatic speech recognition system directly, that is, without manual work with raw signals. Despite the good recognition quality, this model has some drawbacks. These disadvantages are based on the need for a large amount of data for training. This is a serious problem for low-data languages, especially Turkic languages such as Kazakh and Azerbaijani. To solve this problem, various methods are needed to apply. Some methods are used for end-to-end speech recognition of languages belonging to the group of languages of the same family (agglutinative languages). Method for low-resource languages is transfer learning, and for large resources – multi-task learning. To increase efficiency and quickly solve the problem associated with a limited resource, transfer learning was used for the end-to-end model. The transfer learning method helped to fit a model trained on the Kazakh dataset to the Azerbaijani dataset. Thereby, two language corpora were trained simultaneously. Conducted experiments with two corpora show that transfer learning can reduce the symbol error rate, phoneme error rate (PER), by 14.23 % compared to baseline models (DNN+HMM, WaveNet, and CNC+LM). Therefore, the realized model with the transfer method can be used to recognize other lowresource languages © 2022, Authors. This is an open access article under the Creative Commons CC BY license
The nanotubular structure of titanium dioxide (TiO2) is most suitable for creating high-performance energy storage and conversion devices. This paper reports on the synthesis of an array of nanotubes (NTs) from TiO2 by electrochemical anodization of titanium sheets using electrolytes based on fluorine and glycerol. The results of SEM and X-ray spectral analysis of the obtained material revealed the anatase phase of TiO2 nanotubes with an inner diameter of 96–150 nm and a length of 0.6 ± 0.1 μm. The electrochemical behavior of the resulting electrode was studied in a solution of Mg(TFSI)2 based on ethylene carbonate/dimethyl carbonate (1/1). From the cyclic voltammograms, the diffusion coefficient and rate constant were determined to be 1.51·10−10 cm2·s−1, k = 1.55·10−10 cm·s−1 (reduction), respectively. The value of the Coulomb efficiency at low discharge current is higher (88%) than at high discharge current (56%). At a high discharge current (1C), it is noticeable that the charge capacity in the cathodic process is much higher than in the anodic process. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
The problem of the growing shortage of water resources in the world, including in the territory of South-East Kazakhstan, due to global warming and aggravated by long distances to natural sources of good quality water, requires the combined use of surface water and groundwater from local aquifers to supply the local population with high-quality drinking water. The application of methods of artificial groundwater spreading can be an effective way only if positive characteristics of soil and soil parameters of the aeration zone and productive aquifers are obtained in the processes of infiltration and colmatation, which are one of the decisive indicators for ensuring productivity and duration of operation of infiltration basins in the given mode. This work presents the main results of complex field studies of the processes of infiltration and colmatation in infiltration mini-basins at pilot sites within the Aksu, Lepsy and Koksu river valleys, taken as typical for the territory of South-Eastern Kazakhstan, which most needs to increase the water supply of rural population settlements and remote pastures. These studies were supplemented by a detailed assessment of the water-physical, hydrodynamic and filtration properties of the overburden and the upper layers of the aquifer. The new data showed that the infiltration rate varied from 15 m/day at the beginning to 0.75 m/day at the end and remained practically unchanged by the end of the experiment. This was largely facilitated by the values of the heterogeneity coefficient of the granulometric composition of all the examined soils obtained during the studies, which did not exceed 3.0 due to the uniform distribution of coarse fractions and a small proportion of loams and sandy loams. Approximately one month after the start of the tests, a colmatation layer began to be generated at the bottom of the mini-ponds, the thickness of which by the end of the test reached from 3 mm for clay silt to 6 mm for silty clay. However, as studies have shown, the generation of a colmatation layer due to the settling of suspended particles of surface water did not significantly impact on the infiltration processes, as evidenced by the rated values of specific flow rates, which in the final period of time ranged from 0.86 to 0.75-0.80 m3/day per square meter of reduced infiltration surface. Thus, the generated positive results of field studies can serve as a factual basis for design, and can also be recommended and accepted as design indicators both at the stage of a feasibility study and at the stage of detailed design of artificial groundwater spreading systems without additional labor-intensive and costly survey works, and the approved methodology for their implementation will be useful when conducting similar studies in other regions. © 2023, Zibeline International Publishing Sdn. Bhd.. All rights reserved.