Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Article Types

Countries / Regions

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Search Results (283)

Search Parameters:
Keywords = Tajikistan

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
23 pages, 5337 KB  
Article
Hydrogeochemical Characteristics of Hot Springs and Mud Volcanoes and Their Short-Term Seismic Precursor Anomalies Around the Muji Fault Zone, Northeastern Pamir Plateau
by Shihan Cui, Fenna Zhang, Xiaocheng Zhou, Jingchao Li, Jiao Tian, Zhaojun Zeng, Yuwen Wang, Bingyu Yao, Gaoyuan Xing, Jinyuan Dong, Miao He, Han Yan, Ruibin Li, Wan Zheng, Kayimu Saimaiernaji, Chengguo Wang, Wei Yan and Rong Ma
Water 2025, 17(22), 3241; https://doi.org/10.3390/w17223241 - 13 Nov 2025
Abstract
The Muji Fault Zone (MJF) in the northeastern Pamir Plateau hosts a well-developed non-volcanic geothermal system, characterized by widespread hot springs and mud volcanoes—where core processes of geothermal fluids, including atmospheric precipitation recharge, shallow crustal circulation, carbonate-driven water–rock interactions, and CO2-rich [...] Read more.
The Muji Fault Zone (MJF) in the northeastern Pamir Plateau hosts a well-developed non-volcanic geothermal system, characterized by widespread hot springs and mud volcanoes—where core processes of geothermal fluids, including atmospheric precipitation recharge, shallow crustal circulation, carbonate-driven water–rock interactions, and CO2-rich fluid discharge, are tightly coupled with regional intense crustal deformation and frequent seismic activity. We collected and analyzed 22 geothermal water samples and 8 bubbling gas samples from the MJF periphery, finding that the geothermal waters are predominantly of the HCO3-Ca·Mg hydrochemical type, with hydrogen (δD: −103.82‰ to −70.21‰) and oxygen (δ18O: −14.89‰ to −10.10‰) isotopes indicating atmospheric precipitation as the main recharge source. The Na-K-Mg ternary diagram classified the waters as immature, reflecting low-temperature water–rock interactions in the shallow crust (<3 km), while noble gas isotopes (3He/4He: 0.03–0.09 Ra, Ra = 1.43 × 10−6) and carbon isotopes (δ13C-CO2) confirmed fluid origin from crustal carbonate dissolution; SiO2 geothermometry estimated thermal reservoir temperatures at 67–155 °C. Long-term monitoring (May 2019–April 2024) of Tahman (THM) and Bulake (BLK) springs revealed significant pre-seismic anomalies: before the 2023 Tajikistan Ms7.2 and 2024 Wushi Ms7.1 earthquakes, Na+, Cl, and SO42− concentrations showed notable negative anomalies (exceeding 2σ of background values) with synchronous trends between the two springs. Integrating these findings, a “Fault-Spring-Mud Volcano-Earthquake” fluid response model was established, providing direct evidence of deep-shallow fluid coupling in mud volcano–geothermal fluid interactions. This study enhances understanding of the dynamic evolution of non-volcanic geothermal systems under tectonic stress and clarifies the mechanisms of hydrogeochemical variations in fault-controlled geothermal systems, offering a robust scientific basis for advancing research on tectonic–fluid interactions in active fault zones of the northeastern Pamir Plateau. Full article
Show Figures

Figure 1

14 pages, 3625 KB  
Article
Research on Electrical Properties of the Cutting Zone in Cutting Metal/Insulation Materials
by Bohua Feng, Chen Yang, Qianying Zhou, Xiaomei Guo, Qurbonalizoda Saidabdullo Shamsullo, Gaoan Zheng, Zeqi Tong and Xuefeng Xu
Processes 2025, 13(11), 3587; https://doi.org/10.3390/pr13113587 - 6 Nov 2025
Viewed by 212
Abstract
The cutting process is accompanied by complex electrical phenomena, which are particularly evident in narrow cutting clearances. To further explore the laws of electrical phenomena in the capillary of the cutting zone, this paper uses a Faraday collector with an external bias electric [...] Read more.
The cutting process is accompanied by complex electrical phenomena, which are particularly evident in narrow cutting clearances. To further explore the laws of electrical phenomena in the capillary of the cutting zone, this paper uses a Faraday collector with an external bias electric field to investigate the electrical phenomena in the narrow slit of the cutting zone under different cutting parameters and when different tool and workpiece materials are combined. The results show that there is a stable and continuous electrical phenomenon in the cutting contact area, and the emission intensity of charged particles when cutting insulating materials is significantly higher than that of metals. The emission intensity of negative ions is higher than that of positive ions. The electrical and mechanical properties of materials have a significant impact on the electrical phenomena in the cutting zone. In addition, it was found that there is a linear relationship between the electrical phenomena in the cutting zone and the cutting parameters. Finally, based on the morphology of the capillaries in the cutting zone, the self-excited electric field intensity generated in it during the cutting process was estimated. Full article
(This article belongs to the Section Materials Processes)
Show Figures

Figure 1

20 pages, 3920 KB  
Article
Impact Analysis of Climate Change on Hydropower Resource Development in the Vakhsh River Basin of Tajikistan
by Hailong Liu, Aminjon Gulakhmadov and Firdavs Shaimuradov
Hydrology 2025, 12(11), 294; https://doi.org/10.3390/hydrology12110294 - 5 Nov 2025
Viewed by 244
Abstract
With increasing energy demands and environmental pressures, hydropower, as a clean and renewable energy source, has attracted widespread attention for its development and utilization. However, hydropower systems are highly sensitive to climate change, significantly impacting generation, management, and safety. This study addresses the [...] Read more.
With increasing energy demands and environmental pressures, hydropower, as a clean and renewable energy source, has attracted widespread attention for its development and utilization. However, hydropower systems are highly sensitive to climate change, significantly impacting generation, management, and safety. This study addresses the stability of hydropower resources in the Vakhsh River Basin, Tajikistan, using digital analysis, snowmelt runoff simulation, and soil erosion assessment to estimate spatial distribution. Under three climate scenarios (RCP2.6, RCP4.5, and RCP8.5), hydropower trends were simulated, and soil erosion was quantified. Results show annual hydropower potentials: Garm (55.465 billion kWh/a), Rogun (112.737 billion kWh/a), Nurex (78.853 billion kWh/a). Across all scenarios, runoff and hydropower generation increase (162–328,108 kWh/a), with growth rates following RCP4.5 < RCP2.6 < RCP8.5. Soil erosion simulation results indicate that a one millimeter increase in precipitation could lead to sediment deposition of 1.57 × 106 kWh/year in upstream reservoirs. These results demonstrate that climate change has a significant impact on hydropower development in the Vakhsh River Basin. The research provides technical support for hydropower development under climate change. Full article
(This article belongs to the Topic Advances in Hydrological Remote Sensing)
Show Figures

Figure 1

19 pages, 2175 KB  
Article
Pomegranate Germplasm Collections from Elche (Spain) and Bari (Italy): Genetic Resources Characterization for Emerging Mediterranean Challenges
by Ana Lozano-Soria, Agata Gadaleta, Ilaria Marcotuli, Giuseppe Ferrara, Andrea Mazzeo, Julián Bartual and Elena Zuriaga
Plants 2025, 14(21), 3239; https://doi.org/10.3390/plants14213239 - 22 Oct 2025
Viewed by 418
Abstract
Pomegranate (Punica granatum L.) is a strategic crop for Mediterranean agriculture due to its adaptability to arid environments—an increasingly important trait in the context of climate change—and its rising market demand driven by nutritional and medicinal properties. To support breeding and conservation [...] Read more.
Pomegranate (Punica granatum L.) is a strategic crop for Mediterranean agriculture due to its adaptability to arid environments—an increasingly important trait in the context of climate change—and its rising market demand driven by nutritional and medicinal properties. To support breeding and conservation efforts, this study evaluated the genetic diversity and phenotypic traits of two Mediterranean germplasm collections from Elche (Spain) and Bari (Italy). A total of 184 accessions were analyzed using SSR markers and evaluated for key pomological and phenological traits, including fruit weight, skin and aril color, seed hardness, aril weight, titratable acidity, soluble solids content, and harvest time. Genetic analyses revealed high levels of diversity within and between collections, with clear population structure influenced by geographic origin. Phenotypic evaluation revealed considerable variation in agronomic and quality traits, and several accessions with notably desirable characteristics were identified. For example, Ovadan and Molla Nepes displayed very high soluble solids content (>19 °Bx), Sanrà Nero, Sanrà Rosso, and Tajikistan Dark Red exhibited titratable acidity exceeding 40 g/L citric acid, and De Marco reached aril weights of up to 0.60 g. The integration of molecular and morphological data provided valuable insights into the distinctiveness and breeding potential of the studied genotypes. Misclassifications were identified, as well as phenotypic differences attributable to environmental influences. These findings highlight the importance of characterizing regional germplasm to preserve local adaptations and support development of new cultivars adapted to changing environmental conditions. This work reinforces the role of European pomegranate collections as reservoirs of genetic resources for sustainable cultivation and future breeding programs. Full article
(This article belongs to the Special Issue Characterization and Conservation of Vegetable Genetic Resources)
Show Figures

Graphical abstract

28 pages, 1267 KB  
Review
Mapping the Field: A Scoping Review of Initial Teacher Education Research in Central Asia
by Assel Sharimova, Naureen Durrani and Gullala Jumamuratova
Educ. Sci. 2025, 15(10), 1381; https://doi.org/10.3390/educsci15101381 - 16 Oct 2025
Viewed by 1911
Abstract
This study maps the landscape of initial teacher education (ITE) research in Central Asia and its positioning within global academic discourse between 2004 and 2024. Drawing on a systematic scoping review of 144 publications conducted using the PRISMA-ScR protocol, it analyses publication trends, [...] Read more.
This study maps the landscape of initial teacher education (ITE) research in Central Asia and its positioning within global academic discourse between 2004 and 2024. Drawing on a systematic scoping review of 144 publications conducted using the PRISMA-ScR protocol, it analyses publication trends, methodological approaches and thematic foci. The findings indicate that although Central Asia’s contributions to global ITE discourse remain limited, scholarly output is growing, particularly in Kazakhstan, while publications from Tajikistan and Turkmenistan are notably absent. Most studies are empirical and predominantly quantitative, with a strong thematic focus on curriculum-related areas, with limited attention to research and practicum in ITE programmes, teaching practices of teacher educators and educational reform and policies in the field, including issues of equity. By critically assessing these trends, the study identifies key gaps and proposes directions for future research, contributing to a more coherent and connected body of ITE scholarship in and on Central Asia. As the first synthesis of ITE research across the region, it offers a foundation for comparative analysis and cross-national dialogue on teacher education reform. Full article
(This article belongs to the Section Teacher Education)
Show Figures

Figure 1

13 pages, 463 KB  
Article
Enhancing Food Security in an Asian Regional Organization: The Case of the Economic Cooperation Organization
by Alexandra Zamfirache and Ileana Tache
Economies 2025, 13(9), 274; https://doi.org/10.3390/economies13090274 - 19 Sep 2025
Viewed by 649
Abstract
This study investigates the agri-food sector, food trade, and food availability (as a component of food security) within the Economic Cooperation Organization (ECO), emphasizing the critical importance of agriculture across its member states. This significance is particularly pronounced in less industrialized countries such [...] Read more.
This study investigates the agri-food sector, food trade, and food availability (as a component of food security) within the Economic Cooperation Organization (ECO), emphasizing the critical importance of agriculture across its member states. This significance is particularly pronounced in less industrialized countries such as Tajikistan, Kyrgyzstan, and Afghanistan. The rationale behind this research stems from the observation that food trade and food security issues in the ECO region remain insufficiently addressed in the academic literature. Given the strategic geographical position of ECO countries—at the intersection of Europe, Asia, and the Middle East—these states possess considerable potential to function as vital trade hubs. The present study addresses this research gap by offering conceptual insights and empirical data relevant to the region’s policymakers, traders, and other stakeholders. Methodologically, the research integrates both qualitative and quantitative approaches. On the qualitative side, it includes historical and documentary analysis concerning ECO’s evolution and its agri-food sector’s development. Quantitatively, the study employs a regression model to examine the moderating effect of food imports on the relationship between food exports and food availability across member states. The results indicate a significant interaction effect: food imports moderate the negative association between exports and domestic food availability. Drawing on these findings, the paper formulates a set of policy recommendations to enhance agricultural trade strategies and strengthen food security in ECO countries. Full article
(This article belongs to the Special Issue The Agri-Food Sector and the Development of Local Markets)
Show Figures

Figure 1

25 pages, 524 KB  
Review
Research in the Commonwealth of Independent States on Superconducting Materials: Current State and Prospects
by Sanat Tolendiuly, Adil Akishev, Sergey Fomenko, Jaafar Nur-Akasyah, Abu Bakar Putra Ilhamsyah and Nursultan Rakhym
Materials 2025, 18(18), 4299; https://doi.org/10.3390/ma18184299 - 13 Sep 2025
Viewed by 549
Abstract
An overview of research on superconducting materials has been provided, including brief annotations of published papers and scientific cooperation among the Commonwealth of Independent States (CIS) countries: Armenia, Azerbaijan, Belarus, Kazakhstan, Kyrgyzstan, Moldova, Russia, Tajikistan, Turkmenistan, Ukraine, and Uzbekistan. It is shown that [...] Read more.
An overview of research on superconducting materials has been provided, including brief annotations of published papers and scientific cooperation among the Commonwealth of Independent States (CIS) countries: Armenia, Azerbaijan, Belarus, Kazakhstan, Kyrgyzstan, Moldova, Russia, Tajikistan, Turkmenistan, Ukraine, and Uzbekistan. It is shown that fundamental research on superconducting materials is being funded for development and study more at the government level in each republic than from private funds or organizations. One of the most promising materials, as indicated by recent studies, are those synthesized from metal hydrides, particularly lanthanum hydride, which exhibits superconducting properties at 203–253 K, close to room temperature. Unfortunately, this type of material’s practical application is currently limited because of the extremely high pressure necessary during exploitation. The most promising direction, as inferred from research conducted in CIS countries, is the development of cuprate superconductors doped with rare-earth elements such as yttrium, lanthanum, and other metals. There are also iron–nitrogen junctions, metallic and organic superconductors, and research into improving technologies for producing ultrathin substrates using laser or plasma deposition methods. CIS countries have established a strong scientific foundation in superconductivity, with Russia leading fundamental and experimental advances in high- and low-temperature superconducting materials. Future research will likely focus on improving synthesis techniques for ultrathin superconducting films and exploring novel doped hydride systems to achieve stable superconductivity near ambient temperatures. Full article
(This article belongs to the Section Materials Physics)
Show Figures

Figure 1

22 pages, 855 KB  
Systematic Review
Prevalence of Tuberculosis in Central Asia and Southern Caucasus: A Systematic Literature Review
by Malika Idayat, Elena von der Lippe, Nailya Kozhekenova, Oyunzul Amartsengel, Kamila Akhmetova, Ainash Oshibayeva, Zhansaya Nurgaliyeva and Natalya Glushkova
Diagnostics 2025, 15(18), 2314; https://doi.org/10.3390/diagnostics15182314 - 12 Sep 2025
Viewed by 1449
Abstract
Background: In 2023, tuberculosis (TB) caused 1.25 million deaths globally, remaining a leading infectious killer. Central Asia and Southern Caucasus face high TB burdens, particularly Mongolia. This review synthesizes TB prevalence data and diagnostic capabilities in these regions to support public health [...] Read more.
Background: In 2023, tuberculosis (TB) caused 1.25 million deaths globally, remaining a leading infectious killer. Central Asia and Southern Caucasus face high TB burdens, particularly Mongolia. This review synthesizes TB prevalence data and diagnostic capabilities in these regions to support public health strategies. Methods: This systematic review aimed to synthesize current data on TB prevalence in Central Asia, Southern Caucasus, and Mongolia to support public health strategies and research priorities. A comprehensive search of PubMed and Google Scholar was conducted for English-language articles published up to 2023. Studies were assessed using a modified Newcastle–Ottawa Scale. Nine studies met the inclusion criteria, covering Kazakhstan, Kyrgyzstan, Uzbekistan, Tajikistan, Turkmenistan, Mongolia, Georgia, Armenia, and Azerbaijan. Results: TB incidence ranged from 67 per 100,000 in Kazakhstan to 190 per 100,000 in Kyrgyzstan, with the highest prevalence of 68.5% in Mongolia. TB affected men more frequently (65.3%), and the key risk factors included HIV (30.5%), comorbidities, and undernutrition. Diagnostic performance varied significantly (microscopy sensitivity, 45–65%; GeneXpert MTB/RIF, 89–96% sensitivity and 98% specificity for rifampicin resistance). Diagnostic turnaround times ranged from hours (molecular) to weeks (conventional). Only 58% of TB facilities had GeneXpert technology, with urban–rural disparities in diagnostic access. Drug-resistant TB imposed a significant economic burden, with treatment costs ranging from USD 106 to USD 3125. Conclusions: Strengthening surveillance, improving data collection, and conducting longitudinal studies are essential for designing effective TB control strategies in these regions. Significant diagnostic gaps persist across these regions, especially with regard to drug-resistant strains. Point-of-care molecular diagnostics, improved algorithms, and expanded laboratory training show promise. Future research should focus on rapid biomarker-based diagnostics, field-deployable technologies for settings with limited resources, and AI integration to enhance diagnostic accuracy and efficiency. Full article
Show Figures

Figure 1

18 pages, 5932 KB  
Article
Surface Elevation Dynamics of Lake Karakul from 1991 to 2020 Inversed by ICESat, CryoSat-2 and ERS-1/2
by Zihui Zhang, Ping Ma, Xiaofei Wang, Jiayu Hou, Qinqin Zhang, Yuchuan Guo, Zhonglin Xu, Yao Wang and Kayumov Abdulhamid
Remote Sens. 2025, 17(16), 2816; https://doi.org/10.3390/rs17162816 - 14 Aug 2025
Viewed by 552
Abstract
High-altitude lakes are sensitive indicators of climate change, reflecting the hydrological impacts of global warming in alpine regions. This study investigates the long-term dynamics of the water level and surface area of Lake Karakul on the eastern Pamir Plateau from 1991 to 2020 [...] Read more.
High-altitude lakes are sensitive indicators of climate change, reflecting the hydrological impacts of global warming in alpine regions. This study investigates the long-term dynamics of the water level and surface area of Lake Karakul on the eastern Pamir Plateau from 1991 to 2020 using integrated satellite altimetry data from ERS-1/2, ICESat, and CryoSat-2. A multi-source fusion approach was applied to generate a continuous time series, overcoming the temporal limitations of individual missions. The results show a significant upward trend in both water level and area, with an average lake level rise of 8 cm per year and a surface area increase of approximately 13.2 km2 per decade. The two variables exhibit a strong positive correlation (r = 0.84), and the Mann–Kendall test confirms the significance of the trends at the 95% confidence level. The satellite-derived water levels show high reliability, with an RMSE of 0.15 m when compared to reference data. These changes are primarily attributed to increased glacial meltwater inflow, driven by regional warming and accelerated glacier retreat, with glacier area shrinking by over 10% from 1978 to 2001 in the eastern Pamir. This study highlights the value of integrating multi-sensor satellite data for monitoring inland waters and provides critical insights into the climatic drivers of hydrological change in high-altitude endorheic basins. Full article
Show Figures

Figure 1

29 pages, 8648 KB  
Article
Design and Experimentation of Comb-Spiral Impact Harvesting Device for Camellia oleifera Fruit
by Fengxin Yan, Yaoyao Zhu, Xujie Li, Yu Zhang, Komil Astanakulov and Naimov Alisher
Agriculture 2025, 15(15), 1616; https://doi.org/10.3390/agriculture15151616 - 25 Jul 2025
Viewed by 601
Abstract
Camellia oleifera is one of the four largest woody oil species in the world, with more than 5 million hectares planted in China alone. Reducing bud damage and improving harvesting net rate and efficiency have become the key challenges to mechanized harvesting of [...] Read more.
Camellia oleifera is one of the four largest woody oil species in the world, with more than 5 million hectares planted in China alone. Reducing bud damage and improving harvesting net rate and efficiency have become the key challenges to mechanized harvesting of Camellia oleifera fruits. This paper presents a novel comb-spiral impact harvesting device primarily composed of four parts, which are lifting mechanism, picking mechanism, rotating mechanism, and tracked chassis. The workspace of the four-degree-of-freedom lifting mechanism was simulated, and the harvesting reachable area was maximized using MATLAB R2021a software. The picking mechanism, which includes dozens of spirally arranged impact pillars, achieves high harvesting efficiency through impacting, brushing, and dragging, while maintaining a low bud shedding rate. The rotary mechanism provides effective harvesting actions, and the tracked chassis guarantees free movement of the equipment. Simulation experiments and field validation experiments indicate that optimal performance can be achieved when the brushing speed is set to 21.45 r/min, the picking finger speed is set to 341.27 r/min, and the picking device tilt angle is set to 1.0°. With these parameters, the harvesting quantity of Camellia oleifera fruits is 119.75 kg/h, fruit shedding rate 92.30%, and bud shedding rate as low as 9.16%. This new model for fruit shedding and the comb-spiral impact harvesting principle shows promise as a mechanized harvesting solution for nut-like fruits. Full article
Show Figures

Figure 1

15 pages, 943 KB  
Systematic Review
The Implementation of Antimicrobial Consumption Surveillance and Stewardship in Human Healthcare in Post-Soviet States: A Systematic Review
by Zhanar Kosherova, Dariga Zhazykhbayeva, Ainur Aimurziyeva, Dinagul Bayesheva and Yuliya Semenova
Antibiotics 2025, 14(8), 749; https://doi.org/10.3390/antibiotics14080749 - 25 Jul 2025
Cited by 2 | Viewed by 1195
Abstract
Background/Objectives: Antimicrobial consumption (AMC) surveillance and antimicrobial stewardship (AMS) constitute effective strategies to combat the increasing antimicrobial resistance rates worldwide. Post-Soviet countries (Armenia, Azerbaijan, Belarus, Estonia, Georgia, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Moldova, the Russian Federation, Tajikistan, Turkmenistan, Ukraine, and Uzbekistan) implemented various elements [...] Read more.
Background/Objectives: Antimicrobial consumption (AMC) surveillance and antimicrobial stewardship (AMS) constitute effective strategies to combat the increasing antimicrobial resistance rates worldwide. Post-Soviet countries (Armenia, Azerbaijan, Belarus, Estonia, Georgia, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Moldova, the Russian Federation, Tajikistan, Turkmenistan, Ukraine, and Uzbekistan) implemented various elements of AMC surveillance and AMS to different extents. The limited quantity and quality of data from post-Soviet countries make it difficult to assess health system performance; therefore, this region is a blind spot in global AMR monitoring. This systematic review assesses and characterises AMC surveillance and AMS implementation in post-Soviet countries. Methods: Evidence was compiled via a search in PubMed, Google Scholar, Embase, CyberLeninka, and Scopus. The eligibility criteria included AMC surveillance- and AMS-related papers in human health within defined regions and timelines. Some literature from the official websites of international and national health organisations was included in the search. Results: As a result of the searches, screening, and critical appraisal, three peer-reviewed publications and 31 documents were selected for analysis. Eleven out of fifteen countries with updated national action plans for combating antimicrobial resistance have defined AMC surveillance and AMS as strategic objectives. All 15 examined countries submitted antimicrobial consumption data to international networks and reported the existence of approved laws and regulations on antibiotic sales. However, disparities exist in the complexity of monitoring systems and AMS implementation between high-income and low-income countries in the region. Conclusions: This review provides key insights into the existing AMC surveillance and AMS implementation in former Soviet countries. Although the approach of this review lacks quantitative comparability, it provides a comprehensive qualitative framework for national-level AMC surveillance and AMS system assessment. Full article
Show Figures

Figure 1

24 pages, 3436 KB  
Article
Peculiarities of 222Radon and 238Uranium Behavior in Mineral Waters of Highland Terrains
by George Chelnokov, Vasilii Lavrushin, Natalya Kharitonova, Andrey Pavlov and Farid Salikhov
Water 2025, 17(15), 2211; https://doi.org/10.3390/w17152211 - 24 Jul 2025
Viewed by 598
Abstract
Mineral waters from two tectonically active mountain systems within the Alpine-Himalayan orogenic belt, the Pamir and the Greater Caucasus (Elbrus region), were analyzed for 222Rn activity and 238U concentrations to establish correlations with geological conditions, physicochemical characteristics of water, and to [...] Read more.
Mineral waters from two tectonically active mountain systems within the Alpine-Himalayan orogenic belt, the Pamir and the Greater Caucasus (Elbrus region), were analyzed for 222Rn activity and 238U concentrations to establish correlations with geological conditions, physicochemical characteristics of water, and to assess the potential health risk associated with 238U and 222Rn. It was found that in mineral waters of the Pamir, the concentrations of 238U (0.004–13.3 µg/L) and activity of 222Rn (8–130 Bq/L) are higher than in the Elbrus area: 0.04–3.74 µg/L and 6–33 Bq/L, respectively. Results indicate that uranium mobility in water is strongly influenced by T, pH, and Eh, but is less affected by the age of host rocks or springs′ elevation, whereas radon activity in waters depends on the age of rocks, spring elevation, 238U content, and values of δ18O and δ2H in water. This study reveals fundamental geological distinctions governing uranium and radon sources in the mineral waters of these regions. Isotopic evidence (222Rn and 3He/4He) demonstrates crustal radon sources prevail in Pamir, whereas the Elbrus system suggests mantle-derived components. The U concentrations do not exceed 30 µg/L, and most water samples (94%) showed 222Rn activities below 100 Bq/L, complying with the drinking water exposure limits recommended by the World Health Organization and European Union Directive. However, in intermountain depressions of the Pamirs, at low absolute elevations (~2300 m), radon concentrations in water can increase significantly, which requires special attention and study. Full article
Show Figures

Figure 1

19 pages, 3119 KB  
Article
Aquathermolytic Upgrading of Zarafshanian Extra Heavy Oil Using Ammonium Alum
by Amirjon Ali Akhunov, Firdavs Aliev, Nurali Mukhamadiev, Oscar Facknwie Kahwir, Alexey Dengaev, Mohammed Yasin Majeed, Mustafa Esmaeel, Abdulvahhab Al-Qaz, Oybek Mirzaev and Alexey Vakhin
Molecules 2025, 30(14), 3013; https://doi.org/10.3390/molecules30143013 - 18 Jul 2025
Viewed by 820
Abstract
The growing global demand for energy necessitates the efficient utilization of unconventional petroleum resources, particularly heavy oil reserves. However, extracting, transporting, and processing these resources remain challenging due to their low mobility, low API gravity, and significant concentrations of resins, asphaltenes, heteroatoms, and [...] Read more.
The growing global demand for energy necessitates the efficient utilization of unconventional petroleum resources, particularly heavy oil reserves. However, extracting, transporting, and processing these resources remain challenging due to their low mobility, low API gravity, and significant concentrations of resins, asphaltenes, heteroatoms, and metals. In recent years, various in situ upgrading techniques have been explored to enhance heavy oil quality, with catalytic aquathermolysis emerging as a promising approach. The effectiveness of this process largely depends on the development of cost-effective, environmentally friendly catalysts. This study investigates the upgrading performance of water-soluble ammonium alum, (NH4)Al(SO4)2·12H2O, for an extra-heavy oil sample from the Zarafshan Depression, located along the Tajikistan–Uzbekistan border. Comprehensive analyses demonstrate that the catalyst facilitates the breakdown of heavy oil components, particularly resins and asphaltenes, into lighter fractions. As a result, oil viscosity was significantly reduced by 94%, while sulfur content decreased from 896 ppm to 312 ppm. Furthermore, thermogravimetric (TG-DTG) analysis, coupled with Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray diffraction (XRD), revealed that the thermal decomposition of ammonium alum produces catalytically active Al2O3 nanoparticles. These findings suggest that ammonium alum is a highly effective water-soluble pre-catalyst for hydrothermal upgrading, offering a viable and sustainable solution for the development of extra-heavy oil fields. Full article
Show Figures

Figure 1

24 pages, 11020 KB  
Article
Monitoring and Assessment of Slope Hazards Susceptibility Around Sarez Lake in the Pamir by Integrating Small Baseline Subset InSAR with an Improved SVM Algorithm
by Yang Yu, Changming Zhu, Majid Gulayozov, Junli Li, Bingqian Chen, Qian Shen, Hao Zhou, Wen Xiao, Jafar Niyazov and Aminjon Gulakhmadov
Remote Sens. 2025, 17(13), 2300; https://doi.org/10.3390/rs17132300 - 4 Jul 2025
Viewed by 1153
Abstract
Sarez Lake, situated at one of the highest altitudes among naturally dammed lakes, is regarded as potentially hazardous due to its geological setting. Therefore, developing an integrated monitoring and risk assessment framework for slope-related geological hazards in this region holds significant scientific and [...] Read more.
Sarez Lake, situated at one of the highest altitudes among naturally dammed lakes, is regarded as potentially hazardous due to its geological setting. Therefore, developing an integrated monitoring and risk assessment framework for slope-related geological hazards in this region holds significant scientific and practical value. In this study, we processed 220 Sentinel-1A SAR images acquired between 12 March 2017 and 2 August 2024, using the Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) technique to extract time-series deformation data with millimeter-level precision. These deformation measurements were combined with key environmental factors to construct a susceptibility evaluation model based on the Information Value and Support Vector Machine (IV-SVM) methods. The results revealed a distinct spatial deformation pattern, characterized by greater activity in the western region than in the east. The maximum deformation rate along the shoreline increased from 280 mm/yr to 480 mm/yr, with a marked acceleration observed between 2022 and 2023. Geohazard susceptibility in the Sarez Lake area exhibits a stepped gradient: the proportion of area classified as extremely high susceptibility is 15.26%, decreasing to 29.05% for extremely low susceptibility; meanwhile, the density of recorded hazard sites declines from 0.1798 to 0.0050 events per km2. The spatial configuration is characterized by high susceptibility on both flanks, a central low, and convergence of hazardous zones at the front and distal ends with a central expansion. These findings suggest that mitigation efforts should prioritize the detailed monitoring and remediation of steep lakeside slopes and fault-associated fracture zones. This study provides a robust scientific and technical foundation for the emergency warning and disaster management of high-altitude barrier lakes, which is applicable even in data-limited contexts. Full article
Show Figures

Figure 1

22 pages, 5340 KB  
Article
Vegetation Growth Carryover and Lagged Climatic Effect at Different Scales: From Tree Rings to the Early Xylem Growth Season
by Jiuqi Chen, Yonghui Wang, Tongwen Zhang, Kexiang Liu, Kailong Guo, Tianhao Hou, Jinghui Song, Zhihao He and Beihua Liang
Forests 2025, 16(7), 1107; https://doi.org/10.3390/f16071107 - 4 Jul 2025
Viewed by 585
Abstract
Vegetation growth is influenced not only by current climatic conditions but also by growth-enhancing signals and preceding climate factors. Taking the dominant species, Juniperus seravschanica Kom, in Tajikistan as the research subject, this study combines tree-ring width data with early xylem growth season [...] Read more.
Vegetation growth is influenced not only by current climatic conditions but also by growth-enhancing signals and preceding climate factors. Taking the dominant species, Juniperus seravschanica Kom, in Tajikistan as the research subject, this study combines tree-ring width data with early xylem growth season data (from the start of xylem growth to the first day of the NDVI peak month), simulated using the Vaganov–Shashkin (V-S) model, a process-based tree-ring growth model. This study aims to explore the effects of vegetation growth carryover (VGC) and lagged climatic effects (LCE) on tree rings and the early xylem growth season at two different scales by integrating tree-ring width data and xylem phenology simulations. A vector autoregression (VAR) model was employed to analyze the response intensity and duration of VGC and LCE. The results show that the VGC response intensity in the early xylem growth season is higher than that of tree-ring width. The LCE duration for both the early xylem growth season and tree-ring width ranges from 0 to 11 (years or seasons), with peak LCE response intensity observed at a lag of 2–3 (years or seasons). The persistence of the climate lag effect on vegetation growth has been underestimated, supporting the use of a lag of 0–3 (years or seasons) to study the long-term impacts of climate. The influence of VGC on vegetation growth is significantly stronger than that of LCEs; ultimately indicating that J. seravschanica adapts to harsh environments by modulating its growth strategy through VGC and LCE. Investigating the VGC and LCE of multi-scale xylem growth indicators enhances our understanding of forest ecosystem dynamics. Full article
(This article belongs to the Special Issue Tree-Ring Analysis: Response and Adaptation to Climate Change)
Show Figures

Figure 1

Back to TopTop