Neutral radicals generated by electron impact dissociation of the background gas play important roles in etching and deposition processes in low pressure capacitively coupled plasmas (CCPs). The rate and energy efficiency of producing a given radical depend on the space- and time-dependent electron energy distribution function (EEDF) in the plasma, as well as the electron energy dependent cross sections of the electron-neutral collisions that result in the generation of the radical. For the case of a CCP operated in CF4 gas, we computationally demonstrate that the energy efficiency of generating neutral radicals, such as F atoms can be improved by controlling the EEDF by using tailored voltage waveforms (TVW) instead of single-frequency driving voltage waveforms and that separate control of the radical density and the ion energy can be realized by adjusting the waveform shape at constant peak-to-peak voltage. Such discharges are often used for industrial etching processes, in which the F atom density plays a crucial role for the etch rate. Different voltage waveform shapes, i.e. sinusoidal waveforms at low (13.56 MHz) and high (67.8 MHz) frequencies, peaks- and sawtooth-up TVWs, are used to study their effects on the energy cost / energy efficiency of F atom generation by PIC/MCC simulations combined with a stationary diffusion model. The F atom density is enhanced by increasing the voltage amplitude in the single frequency cases, while the energy cost per F atom generation increases, i.e. the energy efficiency decreases, because more power is dissipated to the ions, as the sheath voltages and the ion energy increase simultaneously. In contrast, using TVWs can result in a lower energy cost and provide separate control of the F atom density and the ion energy. This is explained by the fact that tailoring the waveform shape in this way allows to enhance the high-energy tail of the EEDF during the sheath expansion phase by inducing a non-sinusoidal sheath motion, which results in acceleration of more electrons to high enough energies to generate F atoms via electron-neutral collisions compared to the single frequency cases. Similar effects of TVWs are expected for the generation of other neutral radicals depending on the electron energy threshold and the specific consequences of TVWs on the EEDF under the discharge conditions of interest. © 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
The geologically complex Kyzylzharma groundwater field is located in the south-central part of Kazakhstan in the lower Syr Darya Basin. It supplies the 243,000 population of Kyzylorda City by drinking and agricultural water needs. Numerical modeling was used to predict the consequences of increased groundwater withdrawal for future water supply needs. The results displayed a mean squared error for the groundwater simulations of about 0.6 m and was thus acceptable. The validated transmissivity was between 2 × 10−7 and 2 × 10−5 m/d. These parameters showed that the planned groundwater withdrawal will result in a depression cone reaching 90–100 m below present levels in 2040. Maximum groundwater level drawdown may reach 130 m below present levels. This drawdown increases risks for brackish saltwater intrusion into the main groundwater aquifer. The results point at the depletion of groundwater resources in the Syr Daria Artesian Basin and the risks for groundwater quality, particularly increase in mineralization. The key outcome is the recognition that effective joint management of the Syr Daria Artesian Basin’s groundwater resources, involving both Kazakhstan and Uzbekistan, necessitates development and operation of a joint numerical aquifer model. Building this model is a crucial tool for assessing the sustainable groundwater resources in the region. © 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
The results of experiments on manganese pellets based on beneficiated manganese-containing sludge and the melting of ferromanganese alloy with their use are presented. Via beneficiating manganese-containing sludge (16.32% Mn), a concentrate with a manganese content of 35.2% was obtained. The composition of the charge used to prepare manganese pellets is proposed, and the conditions affecting their strength are determined. It was established that manganese is present in the composition of calcined pellets in the form of jacobsite MnFe2O4 and hausmannite Mn3O4. The formation of a phase of ferrobustamite (Ca0.79Fe0.21)SiO3, a ferrosilico-calcium binder that helps increase the strength of pellets, was found. Ferromanganese alloy was obtained as a result of the melting of calcined manganese pellets in a high-temperature Tamman-type unit. The Fe-Mn-Si alloy corresponds to the DIN 17 564 as-grade FeMn70Si in terms of manganese (63.76%) and silicon (17.21%) contents. The content of limiting impurity elements—carbon and phosphorus—in ferromanganese alloy is within acceptable limits. The structure of Fe-Mn-Si alloy and slag formed during their smelting process were studied. © 2023 by the authors.
The geologically complex Kyzylzharma groundwater field is located in the south-central part of Kazakhstan in the lower Syr Darya Basin. It supplies the 243,000 population of Kyzylorda City by drinking and agricultural water needs. Numerical modeling was used to predict the consequences of increased groundwater withdrawal for future water supply needs. The results displayed a mean squared error for the groundwater simulations of about 0.6 m and was thus acceptable. The validated transmissivity was between 2 × 10−7 and 2 × 10−5 m/d. These parameters showed that the planned groundwater withdrawal will result in a depression cone reaching 90–100 m below present levels in 2040. Maximum groundwater level drawdown may reach 130 m below present levels. This drawdown increases risks for brackish saltwater intrusion into the main groundwater aquifer. The results point at the depletion of groundwater resources in the Syr Daria Artesian Basin and the risks for groundwater quality, particularly increase in mineralization. The key outcome is the recognition that effective joint management of the Syr Daria Artesian Basin’s groundwater resources, involving both Kazakhstan and Uzbekistan, necessitates development and operation of a joint numerical aquifer model. Building this model is a crucial tool for assessing the sustainable groundwater resources in the region. © 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
In order to study processes occurring during manufacturing of thin steel sheet by cold rolling and change of energy-power parameters, simulation was performed using engineering software DEFORM 3D, which allows to reflect rolling technology accurately. Model of treatment process was created, output data, modes and temperature of treatment, motion parameters of rolls and sheets were set, material of workpiece was selected and its properties were determined. During simulation of sheets cold rolling process, Lagrange analysis was used, number of simulation steps was 100. Process of plastic deformation of metal along curved grid was investigated, vector displacement field was determined, and it was found that maximum movement of metal occurs under effect of top roll. Distribution of stress-strain state was investigated and maximum stress in strain zone was determined. Distribution of rolling forces and torque was investigated, which allowed to determine their maximum values. Maximum rolling forces and torque were observed at 7-9 th second of treatment, and in future they were reduced due to the fact that pushing force disappeared and steady process began. © Published under licence by IOP Publishing Ltd.
Oil and other fat rich products such as some processed foods can contain unhealthy amounts of trans fatty acids (TFA) and saturated fatty acids (SFA). Diets rich in TFA have been linked to coronary artery disease. It is necessary to quantify and police the type of fat in foods to assess its risk. For the first time, this study quantifies the TFA content in margarines and spreads sold in the Kazakhstan markets in the period from 2015 to 2021. Fatty acid composition, and importantly TFA levels, were determined in 6 brands of margarines and 5 brands of spreads used in the food industry and by consumers directly in 2015–2017, and in 23 brands of margarines and 23 brands of spreads from 2018 to 2021. The study margarines and spreads had 20.0 ± 0.02 % TFA on average until 2018. In contrast, in the period 2018–2021, the TFA average content was 14.2 ± 0.06 % in margarines, and 10.6 ± 0.05 % in spreads, which is still 7.4 and 6 times higher than the regulatory requirements of the Customs Union (Kazakhstan, Russia, Belarus, Kyrgyzstan) and the EU, respectively. The strong cause effect between TFA and cardiovascular diseases urges Kazakhstan and other countries to reduce TFA in commercial products. It also encourages research and implementation of technical measures to provide healthy food products that effectively comply with national and international regulations regarding TFA content. The aim of the study was to analyze changes in the quality of solid fat products produced in Kazakhstan over time, particularly after the Technical Regulations of the Customs Union came into effect on January 1, 2018. © 2025
Purpose. The research purpose is to increase the efficiency of borehole uranium mining by selecting special decolmating solutions and rational parameters of the technology for influencing the seam near-filter zone of geotechnological boreholes, as well as improving the filtration characteristics of the seam, depending on the mineralogical composition of ores and the structure of sediment-forming materials. Methods. The method of X-ray phase analysis was used to study the powders. The core material samples were studied on transparent sections using a LEICA DM 2500 P microscope. The content of the elemental composition of the ores and host rocks in the samples of the productive horizon was controlled using an atomic emission spectrometer. Findings. Based on the research results, quantitative-qualitative characteristics of the host rocks in the productive horizon, sedimentary formations from technological boreholes have been determined, revealing various levels in the productive hori-zon. It has been found that in the Campanian horizon boreholes, ores have a complex structure and multicomponent sedimentary formations, representing a mixture of sediments of mechanical-chemical origin. Originality. The results of quantitative-qualitative, microscopic, thermal research methods of the characteristics of ore-bearing rocks from various horizons at the Syr Darya depression uranium deposit have been studied and comparatively ana-lyzed. The sedimentary formations of technological boreholes in the productive Santonian, Maastrichtian, Campanian horizons of the Northern Kharasan field, Syr Darya depression, have also been sampled and studied. The choice of the most appropriate composition of chemical reagents for dissolution and prevention of sedimentary formation in porous media has been substan-tiated by the microscopic research method. Practical implications. A detailed study and comparative analysis of the characteristics of ores and host rocks in various productive horizons makes it possible to more accurately plan the mining of blocks, minimizing emerging risks. Using the developed combined technology for intensifying borehole uranium mining, it is possible to increase the efficiency of borehole uranium mining and reduce its operating costs. At the same time, the ecological and industrial safety of the work of intensifying the leaching uranium ores increases. © 2022. Z. Kenzhetaev, K. Togizov, M. Abdraimova, M. Nurbekova.
In this work, the authors conducted a study of urban noise, using control measurements of noise levels on the example of the megacity of Almaty (Republic of Kazakhstan). Based on the experimental data obtained, a noise map was developed. The authors made measurements on four main streets at certain points and at certain times. Also measurements were made at intersections with traffic lights, taking into account the phases of signals (red or green). All the obtained data after processing were mapped using a color scheme. As a result, an experimental noise map of the Bostandyk district of Almaty was created. For the first time in Almaty, the noise map for selected neighborhoods of this district was made at different time intervals (9:00, 16:00, 19:00, 23:00) in accordance with the recommendations on monitoring and creation of noise maps. Sound pressure levels in relation to traffic signals at night and during peak hours were investigated. The results of the study confirmed that the noise levels during daytime exceed the regulatory limit. This work is devoted to the research and improvement of noise pollution mapping and monitoring system in urban environments. © (2024), (Polskie Towarzystwo Inzynierii Ekologicznej (PTIE)). All rights reserved.
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.
Sodium-ion batteries are emerging as a promising and cost-effective alternative to lithium-ion batteries for large-scale applications. Among various anode materials, hard carbon has become a preferred choice for sodium-ion batteries. This study focuses on synthesizing hard carbon from bio-waste cherries and investigating the impact of nitrogen doping strategies on its electrochemical performance. Using urea as a precursor, post nitrogen doping was found to enhance the structural properties of hard carbon, facilitating better penetration of sodium ions into its internal structure. The results revealed that post nitrogen doping significantly improved the capacity of hard carbon, increasing it from 206 mAh g⁻¹ to 274 mAh g⁻¹ at a current density of 20 mA g⁻¹. Additionally, the post nitrogen-doped hard carbon demonstrated an impressive capacity of 110 mAh g⁻¹ at a high current density of 1 A g⁻¹. These findings underscore the potential of nitrogen doping in optimizing hard carbon for sodium-ion battery applications. © 2025 The Authors