Search Results (1,745)

This study investigates the effect of rice husk content (0–60 wt.%) on the thermal, mechanical and rheological properties of polypropylene composites prepared by extrusion and injection molding. A temperature-invariant approach was applied to analyze the viscoelastic properties, allowing the combination of data obtained at different temperatures. The results show that as the husk content increases, the elastic modulus and hardness rise linearly, while the impact strength and elongation at break significantly decrease. Composites with 40–50% filler exhibit a balanced combination of strength and stiffness, as confirmed by the summary data in the table (provide references). The application of the temperature-invariant viscosity method confirmed its effectiveness in evaluating the flow properties of composite melts. The obtained results have practical significance for the development of eco-friendly polymer materials with natural fiber fillers. Full article

This study provides a comprehensive assessment of the population structures, anatomical adaptations, and chloroplast genome organizations of three rare tree species—Fraxinus sogdiana Bunge, Celtis caucasica Willd., and Betula jarmolenkoana Golosk.—from the Northern Tien Shan region of Kazakhstan. Field surveys revealed species-specific demographic patterns, with F. sogdiana and B. jarmolenkoana populations displaying a complete age spectrum and signs of ongoing regeneration, while C. caucasica exhibited a lack of juvenile stages, indicating regeneration failure. Anatomical analysis of leaf and stem tissues highlighted adaptive features aligned with habitat conditions: F. sogdiana showed mesophytic traits suited for riparian environments, C. caucasica displayed xeromorphic structures reflecting drought tolerance, and B. jarmolenkoana demonstrated structural reinforcement adapted to high-altitude stressors. Whole chloroplast genome sequencing revealed conserved quadripartite architecture across species, with minor variations in gene content and inverted repeat boundaries suggesting lineage-specific evolution. The findings underscore the ecological sensitivity and conservation priority of these species and provide foundational data for future ecological monitoring, restoration efforts, and phylogenomic research in Central Asian montane ecosystems. Full article

The Ili River Basin is characterized by complex topography and diverse climatic zones with limited in situ observations. This study evaluates the performance of six widely used precipitation datasets, CHIRPS (Climate Hazards Group InfraRed Precipitation with Station data), ERA5_Land (European Centre for Medium-Range Weather Forecasts—ECMWF Reanalysis 5_Land), GPCC (Global Precipitation Climatology Centre), IMERG (Integrated Multi-satellite Retrievals for GPM), PERSIANN (Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks), and TerraClimate, against ground-based data from 2001 to 2023. The evaluation is conducted across multiple spatial scales and temporal resolutions. At the basin scale, most datasets exhibit strong correlations with in situ observations across all temporal scales (r > 0.7), except for PERSIANN, which demonstrates a relatively weaker performance during summer and winter (r < 0.6). All datasets except ERA5_ Land show low annual and monthly bias (<5%), although larger errors are observed during summer, particularly for IMERG and PERSIANN. Dataset performance generally declines with increasing elevation. Basin-wide gridded evaluations reveal distinct spatial variations across all elevation zones, with CHIRPS showing the strongest ability to capture orographic precipitation gradients throughout the basin. All datasets correctly identified 2008 as a drought year and 2016 as a wet year, even though the magnitude and spatial resolution of the anomalies varied among them. These findings highlight the importance of selecting precipitation datasets that are suited to the complex topographic and climatic characteristics of transboundary basins. Our study provides valuable insights for improving hydrological modeling and can be used for water sustainability and flood–drought mitigation support activities in the Ili River Basin. Full article

Over the past 70 years, Central Asia has emerged as a globally recognized water security hotspot due to its unique geographic location and uneven distribution of water resources. In arid and semi-arid regions, understanding runoff dynamics under climate change is essential for ensuring regional water security. This study addresses the data-sparse Central Asian region by applying the ISIMIP3b multi-scenario analysis framework, selecting three representative global hydrological models. Using model intercomparison, trend analysis, and geographically weighted regression, we assess the spatiotemporal evolution of runoff from 1950 to 2080 and investigate the spatial heterogeneity of runoff responses to precipitation and temperature. The results show that under the historical scenario, all models consistently identify similar spatial pattern of runoff, with higher values in southeastern mountainous regions and lower values in western and central regions. However, substantial differences exist in runoff magnitude, with regional annual means of 10, 26, and 68 mm across the three models, respectively. The spatial disparity of runoff distribution is projected to increase under higher SSP scenarios. During the historical period, most of Central Asia experienced a slight decreasing trend in runoff, but the overall trends were −0.022, 0.1, and 0.065 mm/year, respectively. In contrast, future projections indicate a transition to increasing trends, particularly in eastern regions, where trend magnitudes and statistical significance are notably greater than in the west. Meanwhile, the spatial extent of significant trends expands under high-emission scenarios. Precipitation exerts a positive influence on runoff in over 80% of the region, while temperature impacts exhibit strong spatial variability. In the WaterGAP2-2e and MIROC-INTEG-LAND models, temperature has a positive effect on runoff in glaciated plateau regions, likely due to enhanced snow and glacier melt under warming conditions. This study presents a multi-model framework for characterizing climate–runoff interactions in data-scarce and environmentally sensitive regions, offering insights for water resource management in Central Asia. Full article

Zeolites are widely used as adsorbents due to their porous structure and ion-exchange capabilities. However, their adsorption efficiency for heavy metal ions remains limited. To enhance their performance, the natural zeolite heulandite (Z) was functionalized with guanidine derivatives: N-[3-(triethoxysilyl)propyl]guanidine (1), -aminoguanidine (2), and -acetyl-guanidine (3). The resulting materials (Z1–Z3) were evaluated for their ability to adsorb Co²⁺, Cu²⁺, and Ni²⁺ from aqueous solutions. The composition and structure of silanes 1–3 were confirmed by FT-IR and ¹H and ¹³C NMR spectroscopy methods. The modified zeolites were characterized using nitrogen adsorption/desorption (BET) and SEM-EDX to confirm their functionalization and assess the structural changes. A TGA-DSC was used to determine the thermal stability. The adsorption experiments were conducted in single and multi-ionic aqueous solutions at pH 5.0 to evaluate metal uptake. Functionalization significantly improved the adsorption efficiency, with Z1–Z3 showing a three to six times greater adsorption capacity than the unmodified zeolite. The adsorption efficiency followed the trend Cu²⁺ > Co²⁺ > Ni²⁺, primarily due to chelate complex formation between the metal ions and guanidine groups. The SEM-EDX confirmed the co-localization of nitrogen atoms and metal ions. The functional materials (Z1–Z3) exhibited strong potential as adsorbents for noble, heavy, and toxic metal ions, and could find applications in industry, agriculture, ecology, medicine, chemistry, wastewater treatment, soil remediation, chemisorption, filtration, chromatography, etc. Full article

This study presents a scenario-based assessment of the future sensitivity of minimal low-water runoff to climate change in Western Kazakhstan. An ensemble of global climate models from the Coupled Model Intercomparison Project Phase 6 (CMIP6), combined with dynamically downscaled projections for Central Asia, was applied to estimate minimal monthly runoff during the summer–autumn and winter low-water periods for the rivers of the Zhaiyk–Caspian water management basin. The analysis covers three future time horizons: 2040 (2031–2050), 2060 (2051–2070), and 2080 (2071–2090), under two greenhouse gas concentration scenarios: SSP3-7.0 (moderately high emissions) and SSP5-8.5 (high emissions). The results reveal a pronounced seasonal contrast in the projected hydrological response. During the winter low-water period, a steady increase in minimal runoff is projected for all rivers, with the most significant changes observed for the Or, Zhem, Temir, and Shagan rivers. This increase is primarily driven by higher winter precipitation, increased thaw frequency, and enhanced infiltration recharge. Conversely, despite modest increases in summer–autumn precipitation, minimal runoff during the summer–autumn low-water period is projected to decline significantly, particularly in the southern basins, due to elevated evapotranspiration rates and soil moisture deficits associated with rising air temperatures. These findings emphasize the importance of developing seasonally differentiated, climate-resilient water management strategies to mitigate low-flow risks and ensure water security under future climate conditions in arid and semi-arid regions. Full article

Packaging demand currently exceeds 144 Mt per year, of which >90% is conventional plastic, generating over 100 Mt of waste and 1.8 Gt CO₂-eq emissions annually. In this review, we systematically survey three classes of lignocellulosic feedstocks, agricultural residues, fruit and vegetable by-products, and forestry wastes, with respect to their physicochemical composition (cellulose crystallinity, hemicellulose ratio, and lignin content) and key processing pathways. We then examine fabrication routes (solvent casting, extrusion, and compression molding) and quantify how compositional variables translate into film performance: tensile strength, elongation at break (4–10%), water vapor transmission rate, thermal stability, and biodegradation kinetics. Highlighted case studies include the reinforcement of poly(vinyl alcohol) (PVA) with 7 wt% oxidized nanocellulose, yielding a >90% increase in tensile strength and a 50% reduction in water vapor transmission rate (WVTR), as well as pilot-scale extrusion of rice straw/polylactic acid (PLA) blends. We also assess techno-economic metrics and life-cycle impacts. Finally, we identify four priority research directions: harmonizing pretreatment protocols to reduce batch variability, scaling up nanocellulose extraction and film casting, improving marine-environment biodegradation, and integrating circular economy supply chains through regional collaboration and policy frameworks. Full article

Plant growth-promoting rhizobacteria (PGPRs) colonise the rhizosphere and root surfaces, enhancing crop development through a variety of mechanisms. This study evaluated microbial strains isolated from Triticum aestivum L. for key plant growth-promoting traits, including indole-3-acetic acid (IAA) production, phosphate and zinc (Zn) solubilisation, nitrogen (N₂) fixation, and antifungal activity. Among 36 isolates, 3 (AS8, AS23, AS31) exhibited strong growth-promoting potential. IAA production, citrate assimilation, carbohydrate fermentation, and catalase activity were observed to a comparable extent among the selected strains. AS8 showed the highest protease, lipase, and amylolytic activity, while AS23 demonstrated superior phosphate and Zn solubilisation. Notably, AS31 emerged as the most promising multi-trait isolate, exhibiting the highest levels of IAA production, N₂ fixation, antifungal activity against five phytopathogens (Fusarium graminearum, F. solani, F. oxysporum, Pythium aphanidermatum, and Alternaria alternata), potentially linked to its hydrogen sulphide (H₂S) production, and cellulolytic activity. Molecular identification based on 16S rRNA gene sequencing revealed the isolates as Stenotrophomonas indicatrix AS8, Pantoea agglomerans AS23, and Bacillus thuringiensis AS31. Seed germination assays confirmed the plant growth-promoting efficacy of these PGPR strains, with vigour index increases of up to 43.4-fold. Given their positive impact on seed germination and significant Zn-solubilising abilities, the selected strains represent promising candidates for use as bio-inoculants, offering a sustainable and eco-friendly strategy to enhance agricultural productivity in nutrient-deficient soils. Future research should validate the efficacy of these PGPR strains under pot conditions to confirm their potential for practical agricultural applications. Full article

Supercapacitors have begun to successfully compete with Li-ion batteries in various portable energy storage applications, owing to their ability to enable fast charging, deliver high power and energy, and offer an exceptionally long cycle life. This paper presents the results of a study on the performance of a positive electrode composed of a Cu_xZn_1−xCoNiS_yO_4−y whisker layer and an underlying porous Ni₃S₂ layer, synthesized in a single step via the hydrothermal method. The coating with the nominal composition Cu_0.7Zn_0.3CoNiS₃O/Ni₃S₂ exhibited a high specific capacitance of 4.10 C cm⁻² at a current density of 2 mA cm⁻² or 9535 F g⁻¹ at a current density of 1 A g⁻¹, attributed to the synergistic contribution of both layers and the optimized ratio of the four transition metals in the sulfoxide matrix. The assembled asymmetric supercapacitor (ASC), employing the obtained composite as the positive electrode and activated carbon as the negative electrode, exhibited a specific capacitance of 115 F g⁻¹ (200 C g⁻¹). It achieved a high energy density of 48.3 Wh kg⁻¹ at a power density of 870 W kg⁻¹. After 20,000 charge–discharge cycles at a current density of 10 A g⁻¹, the ASC retained 74% of its initial capacitance, highlighting the potential of the Cu_xZn_1−xCoNiS_yO_4−y electrode for high-performance energy storage applications. Full article

Public transport agencies must triage thousands of multilingual complaints every day, yet the cost of training and serving fine-grained sentiment analysis models limits real-time deployment. The proposed “one encoder, any facet” framework therefore offers a reproducible, resource-efficient alternative to heavy fine-tuning for domain-specific sentiment analysis or opinion mining tasks on digital service data. To the best of our knowledge, we are the first to test this paradigm on operational multilingual complaints, where public transport agencies must prioritize thousands of Russian- and Kazakh-language messages each day. A human-labelled corpus of 2400 complaints is embedded with five open-source universal models. Obtained embeddings are matched to semantic “anchor” queries that describe three distinct facets: service aspect (eight classes), implicit frustration, and explicit customer request. In the strict zero-shot setting, the best encoder reaches 77% accuracy for aspect detection, 74% for frustration, and 80% for request; taken together, these signals reproduce human four-level priority in 60% of cases. Attaching a single-layer logistic probe on top of the frozen embeddings boosts performance to 89% for aspect, 83–87% for the binary facets, and 72% for end-to-end triage. Compared with recent fine-tuned sentiment analysis systems, our pipeline cuts memory demands by two orders of magnitude and eliminates task-specific training yet narrows the accuracy gap to under five percentage points. These findings indicate that a single frozen encoder, guided by handcrafted anchors and an ultra-light head, can deliver near-human triage quality across multiple pragmatic dimensions, opening the door to low-cost, language-agnostic monitoring of digital-service feedback. Full article

This study focuses on the development and evaluation of automatic speech recognition (ASR) systems for Kazakh child speech, an underexplored domain in both linguistic and computational research. A specialized acoustic corpus was constructed for children aged 2 to 8 years, incorporating age-related vocabulary stratification and gender variation to capture phonetic and prosodic diversity. The data were collected from three sources: a custom-designed Telegram bot, high-quality Dictaphone recordings, and naturalistic speech samples recorded in home and preschool environments. Four ASR models, Whisper, DeepSpeech, ESPnet, and Vosk, were evaluated. Whisper, ESPnet, and DeepSpeech were fine-tuned on the curated corpus, while Vosk was applied in its standard pretrained configuration. Performance was measured using five evaluation metrics: Word Error Rate (WER), BLEU, Translation Edit Rate (TER), Character Similarity Rate (CSRF2), and Accuracy. The results indicate that ESPnet achieved the highest accuracy (32%) and the lowest WER (0.242) for sentences, while Whisper performed well in semantically rich utterances (Accuracy = 33%; WER = 0.416). Vosk demonstrated the best performance on short words (Accuracy = 68%) and yielded the highest BLEU score (0.600) for short words. DeepSpeech showed moderate improvements in accuracy, particularly for short words (Accuracy = 60%), but faced challenges with longer utterances, achieving an Accuracy of 25% for sentences. These findings emphasize the critical importance of age-appropriate corpora and domain-specific adaptation when developing ASR systems for low-resource child speech, particularly in educational and therapeutic contexts. Full article

The Ile River is the main water artery of the Lake Balkhash basin and the main fresh water resource supplying the south-eastern part of Kazakhstan. Increasing human economic activity makes it necessary to assess the anthropogenic load of the river on various ecosystems, including possible harmful effects. The assessment of anthropogenic load on the Ile River ecosystem was realized by the anthropogenic load fraction indicator and by the values of the chemical substance inflow modulus. For this purpose, the Ile River was divided into 3 sections: section I—from the border post HP Dobyn to 164 km above Kapshagai hydroelectric power plant (HPP); section II—between the points 164 km above and 37 km below Kapshagai HPP; and section III —from 37 km below HPP to Ushzharma village. The anthropogenic load strongly depends on the share of anthropogenic impact contributed by pollutants. Characteristic pollution components are copper, and in some cases zinc, ammonium, and nitrite nitrogen. The assessment of anthropogenic load also considers organic and biogenic substances in the chemical composition of river water. The variability in the volume of dissolved chemical inflows in different sections of the river made it possible to assess the transformation of anthropogenic load along the length of the Ile River. Full article

Eclipsing cataclysmic variables (CVs) are key targets for determining binary system parameters through photometric modeling, yet many of them remain poorly characterized. In this work, we present a list (catalog) of 37 confirmed eclipsing CVs selected based on high-quality and publicly available TESS photometric data. The sample includes both long-period systems (with orbital periods exceeding 4 h), such as Z Cam, U Gem, and nova-like variables, as well as a significant number of SW Sextantis stars. Selection criteria required the presence of clearly defined eclipses and sufficient signal-to-noise ratios for reliable analysis. The catalog provides a foundation for phase-folded light curve studies and future modeling efforts aimed at deriving key physical parameters such as component masses, radii, inclinations, and accretion geometries. Notably, several systems, such as V482 Cam, OZ Dra, ASASSN-14ix, and others, have no previously published physical parameters. Our list is accessible via a dedicated website, where each system will have a separate page, including data from TESS, AAVSO, and ZTF. This resource is intended to support detailed follow-up studies. It may encourage other research groups with observational and modeling expertise to contribute to the investigation of these promising but understudied systems. Full article

In this paper, solvability of some inverse problems for a nonlocal analog of a pseudoparabolic equation is studied. The nonlocal analog of a pseudoparabolic equation is formed using transformations that have the involution property. Two types of inverse problems are considered. In the first problem, in addition to the solution, a function in the right-hand side of the equation depending on the spatial variable is determined. In the second problem, a function depending on the time variable is found. The first problem is solved using the Fourier method, and the second problem is solved by reducing to the integral Volterra equation. Full article

Mixtures containing polyvinyl alcohol (PVA) and methylcellulose (MC) were obtained and used to synthesize hydrogels in various ratios of components. The swelling kinetics of the resulting hydrogels were studied, revealing that the equilibrium swelling degree in artificial saliva is nearly twice as high as in water. It was found that increasing the volumetric content of PVA in the mixture leads to a higher swelling degree. The kinetics of active pharmaceutical ingredient (API) sorption and release from the hydrogels were also investigated. It was demonstrated that hydrogels with a higher PVA content exhibit greater sorption capacity; however, the release of the API from such samples occurs at a slower rate. For the first time, the mucoadhesive properties of PVA-MC-based hydrogels were studied. It was established that the PVA-MC hydrogel with a ratio of 6:4 vol.% remained on the surface of the porcine cheek mucosa for two days, the 5.5:4.5 vol.% sample detached after 24 h, and the 5:5 vol.% sample adhered for approximately 10 h. These findings confirm the mucoadhesive potential of the hydrogels and their suitability for buccal drug delivery forms. The synthesized PVA-MC hydrogels are promising for applications in medicine and pharmacology. Full article