Search Results (3,404)

The chemical stability of tetramethylammonium (TMA) head groups, both with and without the presence of a choline chloride and ethylene glycol-based deep eutectic solvent (DES), was studied using Density Functional Theory (DFT) calculations and ab initio Molecular Dynamics (MD) simulations. DFT calculations of transition state energetics (ΔEreaction, ΔGreaction, ΔEactivation, and ΔGactivation) for key degradation mechanisms, ylide formation (YF) and nucleophilic substitution (SN2), suggested that the presence of DES enhances the stability of the TMA head groups compared to systems without DES. Ab initio MD simulations across hydration levels (HLs) 1 to 5 indicated that without DES, YF dominates at lower HLs, while SN2 does not occur. In contrast, both mechanisms are suppressed in the presence of DES. Temperature also plays a role: without DES, YF dominates at 298 K, while SN2 becomes prominent at 320 K and 350 K. With DES, both degradation mechanisms are inhibited. These findings suggest DES could improve the chemical stability of TMA head groups in anion exchange membranes. Full article

The role of non-cognitive skills in academic achievement has garnered increasing attention in educational research. This study explores the impact of non-cognitive skills on academic achievement in STEM and non-STEM subjects in secondary education. Survey data from 795 teachers and 12,965 students across 20 STEM schools in Kazakhstan were analyzed to examine the impact of 26 non-cognitive skills on performance in math, physics, first language, and history. Regression and mediation analyses were conducted to investigate how students’ self-assessment of non-cognitive skills directly affects academic achievement and how these effects are mediated by teachers’ assessments. The findings indicate that non-cognitive skills exhibit varying direct and total effects, with mediated effects showing greater consistency across different subjects. In math and physics, information processing skill and grit show the strongest direct and total effects on academic achievement. In first language and history, responsibility management and teamwork skill are most influential. Except for capacity for optimism and growth mindset, all skills demonstrated mediated effects across the four subjects. This research informs curriculum development and equitable policies by showing how non-cognitive skills impact academic performance across subjects. It studies the case of Kazakhstan, adding to global education discourse and offering valuable insights for enhancing STEM education. Full article

The article develops a methodological and practical basis for assessing the attractiveness of regional tourist sites from the point of view of educational tourism. An assessment methodology was created, including groups of criteria and sub-criteria (6 and 53, respectively), selected based on expert evaluation; a matrix was formed, allowing us to calculate integral indicators step by step, which was tested on the example of 50 objects of five regions of Kazakhstan (Central, Northern, Southern, Western and Eastern). In addition, the article implements hierarchical cluster analysis on three blocks of parameters: the first—indicators characterizing the level of education development in the context of 17 regions and 3 cities of republican significance; the second—indicators reflecting the cultural development of the country’s regions; the third—parameters showing the level of development of tourism activities in the regions of Kazakhstan, which allowed us to obtain three clusters that can be used to develop recommendations for the development of education in the regions of Kazakhstan. As a conceptual complementary component of the system of implementation of educational tourism, an audio guide “Tourist sites of Karaganda” was developed and uploaded on the izi.Travel platform. Full article

Water treated with ion ozone improves the technological qualities of food products. Therefore, ion-ozonated water was used in the work, and whole-grain flour from soft wheat of the Almaly variety and pumpkin powder were used as raw materials to improve the quality and nutritional value of the pasta. This study investigated the effects of ion-ozone concentration in ion-ozonated water C_io, water temperature t_w, pumpkin powder content C_pp and drying temperature t_d on various characteristics affecting the quality of pasta, including its organoleptic physical, chemical, and rheological properties. These characteristics were assessed by conducting multiple experiments, a total of 25 indicators were determined, such as humidity, acidity, cooking properties, deformation, and other basic quality indicators. To reduce the number of experiments and obtain a reliable assessment of the influence of individual factors on the quality indicators of pasta, methods involving the multifactorial design of experiments were applied. Data processing and all necessary calculations were carried out using the PLAN sequential regression analysis program. Consequently, our findings indicate that minimizing dry water (DM) loss in cooking water requires a dual approach: increasing ion-ozone concentration and optimizing pasta composition and drying conditions, specifically by reducing pumpkin powder content and drying temperature. As a result, it was established that to obtain high-quality pasta from whole-grain flour with high quality and rheological properties, it is necessary to use the following optimal production modes: ion-ozone concentration in ion-ozonated water C_io = 2.5 × 10⁻⁶ mg/cm³, water temperature t_w = 50 °C, pumpkin powder content C_pp = 3.0%, and pasta drying temperature t_d = 50 °C. The resulting pasta is an environmentally friendly product with a high content of biologically active substances. Full article

This research investigates the impact of additives such as activated carbon (AC) combined with metal oxides (Bi₂O₃, MoO₃, and ZnO) on the thermal decomposition kinetics of ammonium nitrate (AN), magnesium (Mg), and nitrocellulose (NC) as a basic AN–Mg–NC composite. To study the thermal properties of the AN–Mg–NC composite with and without the AC–Me_xO_y (Me = Bi, Mo, Zn) additive, a differential scanning calorimetry (DSC) analysis was conducted. The DSC results show that the AC–Me_xO_y (Me = Bi, Mo, Zn) additive catalytically affects the basic AN–Mg–NC composite, lowering the peak decomposition temperature (T_max) from 534.58 K (AN–Mg–NC) to 490.15 K (with the addition of AC), 490.76 K (with AC–Bi₂O₃), 492.17 K (with AC–MoO₃), and 492.38 K (with AC–ZnO) at a heating rate of β equal to 5 K/min. Based on the DSC data, the activation energies (E_a) for the AN–Mg–NC, AN–Mg–NC–AC, and AN–Mg–NC–AC–Me_xO_y (Me = Bi, Mo, Zn) composites were determined using the Kissinger method. The results suggest that incorporating AC and AC–Me_xO_y (Me = Bi, Mo, Zn) additives reduce the decomposition temperatures and activation energies of the basic AN–Mg–NC composite. Specifically, E_a decreased from 99.02 kJ/mol (for AN–Mg–NC) to 93.63 kJ/mol (with addition of AC), 91.45 kJ/mol (with AC–Bi₂O₃), 91.65 kJ/mol (with AC–MoO₃), and 91.76 kJ/mol (with AC–ZnO). These findings underscore the potential of using AC–Me_xO_y (Me = Bi, Mo, Zn) as a catalytic additive to enhance the performance of AN–Mg–NC-based energetic materials, increasing their efficiency and reliability for use in solid propellants. Full article

This article presents the results of a study of the influence of radionuclide and chemical pollution on the morphological and anatomical parameters of Calamagróstis epigéjos plants growing in the territory of “Degelen” at the Semipalatinsk Test Site (STS). Quantitative data of morphological and anatomical parameters are given, and the content of radionuclides and toxic elements in samples of plants obtained. Statistical processing of the obtained data was conducted. The results revealed that elevated concentrations of radionuclides ¹³⁷Cs and ⁹⁰Sr, and the calculated absorbed dose, do not have effects on plants. Changes in the anatomical parameters of leaves and stems were observed at elevated concentrations of the elements: for leaves—Al, Pb, Sr, U, Ni, Rb, Sm; for stems—Al, Cr, Cd, U, Cu, Be, Ni, Sm, Fe. The mesophyll of the leaves and the epidermis of the stems were the most exposed to toxic elements. The data of the anatomical parameters are recommended to be used as indicative parameters of plants grown in chemically contaminated areas. Full article

Both steam and hot water flooding of high-viscosity oils in the presence of swelling clays are difficult methods for producing oil efficiently because of potential formation permeability reduction. This paper pertains to heavy oil recovery from the East Moldabek formation where the oil API gravity is about 22 and is inundated with swelling clays. To achieve this, we used the Intersect^TM reservoir simulator to compare oil recovery economics using both hot water and steam injection as a function of steam cycle duration, temperature, and steam dryness. We also studied clay swelling in the East Moldabek formation where clay poses a significant challenge due to its impact on permeability reduction. In this research, we developed an equation based on experimental data to establish a relationship between water mineralization and permeability in the East Moldabek formation. The equation provides valuable insight on how to mitigate clay swelling which is crucial for enhancing oil recovery efficiency—especially in sandstone reservoirs. Our modeling studies provide the recovery efficiencies for salinities of the hot water EOR versus cyclic steam EOR methods in a formation containing swelling clays. Specifically, the reduction in formation permeability as a function of the distilled water fraction is the controlling parameter in hot water or steam flooding—when the formation water mixture becomes less saline, oil recovery decreases. Our research shows that clay swelling can significantly impact cyclic steam stimulation outcomes, potentially reducing its effectiveness, while hot water flooding may offer a more cost-effective and operationally feasible solution in formations where clay swelling is a concern. Economic analysis reveals the potential for achieving an optimal favorable condition for hot water injection. Therefore, this paper provides a guideline on how to conduct thermal oil recovery for heavy oils in fields with high clay content such as the East Moldabek deposit. Full article

In this work, composite materials were obtained for the first time using various methods and the dependences of the resulting surface morphologies were investigated. This involves modifying the surface with cucurbit[n]urils, which are highly promising macrocyclic compounds. The process includes applying cucurbit[6]uril to the hydroxyapatite surface in water using different modification techniques. The first method involved precipitating a dispersion of CB[6] in undissolved form in water. The second method involved using fully dissolved CB[6] in deionized water, after which the composite materials were dried to constant weight. The third method involved several steps: first, CB[6] was dissolved in deionized water, then, upon heating, a dispersion of CB[6] was formed on the surface of HA. The fourth method involved using ultrasonic treatment. All four methods yielded materials with different surface morphologies, which were studied and characterized using techniques such as infrared (IR) spectroscopy and scanning electron microscopy (SEM). Based on these results, it is possible to vary the properties and surface morphology of the obtained materials. Depending on the method of applying CB[6] to the surface and inside the HA scaffold, it is possible to adjust the composition and structure of the target composite materials. The methods for applying CB[6] to the hydroxyapatite surface enhance its versatility and compatibility with the body’s environment, which is crucial for developing new functional composite materials. This includes leveraging supramolecular systems based on the CB[n] family. The obtained results can be used to model the processes of obtaining biocomposite materials, as well as to predict the properties of future materials with biological activity. Full article

This article provides a comparative analysis of pendulum and radial micro-hydropower plants. The novelty of this study lies in the comparative analysis of units that are fundamentally different in design to achieve the most rational option for low-speed rivers. It has been established that a pendulum micro-hydropower plant has a high torque with relatively small dimensions but operates cyclically. At a diameter of 1 m and a blade area of 0.3 m², the peak torque was 140 N·m. At the same time, the design is sensitive to the blade area and at 0.6 m² and a lever length of 1.5 m, the torque reached 430 N·m. A radial micro-hydropower plant has lower torque but operates constantly. At an area of 1.23 m² and a diameter of 1 m, the torque was 40.4 N·m. Accordingly, in terms of specific area with a diameter of 1 m, a pendulum micro-hydropower plant has up to 12 times more torque. It has been established that the pendulum hydropower plant best satisfies the requirements for converting a low river speed into high revolutions of a current generator. Full article

The increasing deployment of wind turbines in technologically advanced nations underscores the need to enhance their reliability, extend their operational lifespan, and minimize failures. The current protection devices for wind turbine components do not sufficiently shield them from various external factors that degrade performance. This study addresses the environmental and technical challenges that disrupt wind turbine operations and reviews existing research and technical solutions for protecting individual components, supported by experimental findings. Using a decomposition method followed by the integration of protection components, we propose a combined protection system designed to improve the overall resilience of wind turbines. The proposed system aims to reduce incidents, extend service life, and increase reliability, addressing a critical gap in wind energy technology and contributing to its continued development and efficiency. Full article

In this study, we consider the extended optimal control problem and search for a control function in the class of feasible functions for a real control object. Unlike the classical optimal control problem, the control function should depend on the state, not time. Therefore, the control synthesis problem for the initial-state domain should be solved, instead of the optimal control problem with one initial state. Alternatively, an optimal trajectory motion stabilisation system may be constructed. Both approaches—control and trajectory motion stabilisation system syntheses—cannot be applied to real-time control, as the task is too complex. The minimum threshold of quality criteria is searched for in the space of mathematical expression codes. Among other problems, the search space is difficult to define and the gradient is hard to determine. Therefore, the advanced control object model is used to obtain a feasible control function. The advanced model is firstly obtained before solving the optimal control problem and it already includes a trajectory motion stabilisation system; in particular, this stabilisation system is synthesised in advance at the control system design stage. When the optimal control problem appears, it is solved in real time in the classical statement, and a control function is searched for as a function of time. The advanced control object model also uses the reference model to generate the optimal trajectory. The search for the optimal control function is performed in real time and considers the synthesised stabilisation system of motion along a determined trajectory. Machine learning control via symbolic regression, namely, the network operator method, is used to directly solve the control synthesis problem. An example solution of the optimal control problem, with an advanced model moving in the environment with obstacles for a group of two mobile robots, is presented. The obtained solution is a control function for a reference model that generates a trajectory from a class of trajectories stabilised with the object’s control system. Full article

Bovine anaplasmosis is an infectious vector-borne disease caused by bacteria of the genus Anaplasma, which have a wide global distribution and represent a high economic burden for agriculture. The use of molecular genetic techniques has increased our knowledge of the species diversity of Anaplasma spp. and naturally susceptible animals. Monitoring studies allow us to assess the level of infection in herds, as well as the involvement of natural vectors in the processes of maintaining and spreading infection. Despite the high prevalence of Theileria and Babesia in cattle in Kazakhstan, there is no information on the distribution and species diversity of Anaplasma spp in this country. As part of this work, 7027 DNA samples isolated from the whole blood of cattle from 175 settlements in all 17 Kazakhstan regions were PCR-tested for the presence of Anaplasma spp. Anaplasma carriers were found in 1.3% (90 out of 7027) of the tested animals in 9 of the 17 regions of Kazakhstan. The highest percentage of infected animals was recorded in Turkistan (South Kazakhstan) and North Kazakhstan with 4.46% and 2.48% positive samples, respectively. The partial sequencing of 16S rRNA and the groEL gene allowed us to identify five species of Anaplasma: A. centrale, A. marginale, Candidatus Anaplasma Mongolica, A. ovis, and Unknown Anaplasma with infection rates of 0.63%, 0.44%, 0.13%, 0.01%, and 0.01%, respectively. Full article

Nocardia cyriacigeorgica causes bovine mastitis, reduces milk quantity and quality, and is often resistant to antimicrobials. Selenomethionine (SeMet) is a form of selenium, which reduces reactive oxygen species (ROS)-mediated apoptosis and intramammary infections. However, the protective effects of SeMet on N. cyriacigeorgica-infected bovine mammary epithelial cells (bMECs) are unclear. The objective of this study was to evaluate whether SeMet mitigated N. cyriacigeorgica-induced inflammatory injury, oxidative damage and apoptosis in bMECs. Cells were cultured with or without being pretreated with 40 µM of SeMet for 12 h, then challenged with N. cyriacigeorgica (multiplicity of infection = 5:1) for 6 h. Although N. cyriacigeorgica was resistant to lincomycin, erythromycin, enrofloxacin, penicillin, amoxicillin, cephalonium, cephalexin, and ceftriaxone, 40 μM SeMet increased cell viability and inhibited lactate dehydrogenase release in infected bMECs. Furthermore, N. cyriacigeorgica significantly induced mRNA production and protein expression of TNF-α, IL-1β, IL-6, and IL-8 at 6 h. Cell membrane rupture, cristae degeneration and mitochondria swelling were evident with transmission electron microscopy. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) activities were down-regulated after 3, 6, or 12 h, whereas malondialdehyde (MDA) and ROS contents were significantly upregulated, with cell damage and apoptosis rapidly evident (the latter increased significantly in a time-dependent manner). In contrast, bMECs pretreated with 40 μM SeMet before infection, SOD, and GSH-px activities were upregulated (p < 0.05); MDA and ROS concentrations were downregulated (p < 0.05), and apoptosis was reduced (p < 0.05). In conclusion, 40 μM SeMet alleviated inflammation, oxidative stress and apoptosis induced by N. cyriacigeorgica in bMECs cultured in vitro. Full article

This study outlines a method for preparing a complex involving glycoluril and melamine (GU-ME). The structure of the resultant complex was analyzed using IR and NMR spectroscopy. In the subsequent phase, the polymer GUMEFA was derived from the resultant complex, employing hydroxyethylidene diphosphonic acid (HEDP) as a sustainable plasticizer, with a proposed chemical mechanism for its formation. The molecular weight of the resulting GUMEFA was analyzed, and the formation chemistry was proposed. GUMEFA was characterized, and its free formaldehyde and methylol group contents were investigated. It was observed that GUMEFA prepared with HEDP contained approximately 1.15–1.34 wt.% free formaldehyde and 1.56–0.54 wt.% methylol groups. These findings provide valuable insights for developing resins of different compositions and applications, thereby paving the way for producing composite materials with tailored properties. Full article

Sugar beet hybrids are essential in modern agriculture due to their superior yields, disease resistance, and adaptability. This study investigates the role of the Rz2 gene in conferring resistance to beet necrotic yellow vein virus (BNYVV) in 14 sugar beet hybrids cultivated in Kazakhstan, including local and European varieties. The Rz2 gene, encoding a CC-NB-LRR protein, is a known resistance factor against BNYVV. Using RT-qPCR, we assessed Rz2 expression and detected BNYVV in bait plants inoculated with virus-infested soil. Our findings identified two highly resistant varieties: the Kazakh cultivar ‘Abulhair’ and the French line 22b5006. Additionally, the Kazakh cultivar ‘Pamyati Abugalieva’ and the French hybrid ‘Bunker’ exhibited increased resistance, suggesting involvement of other resistance loci. Notably, the Danish hybrid ‘Alando’, despite resistance to rhizomania, did not effectively resist BNYVV, highlighting possible evasion of its genetic factors by local virus strains. Our results emphasize the importance of Rz2 in resistance breeding programs and advocate for further research on additional resistance genes and the genetic variability of BNYVV in Kazakhstan. This work pioneers the molecular evaluation of BNYVV resistance in sugar beet in Kazakhstan, contributing to sustainable disease management and improved sugar beet production. Full article