Primary Water Research Articles

Driving Factors and Numerical Simulation of Evapotranspiration of a Typical Cabbage Agroecosystem in the Shiyang River Basin, Northwest China

Two years of field experiments were conducted at the National Field Observation Experiment Station for Efficient Agricultural Water Use in the Wuwei Oasis, Gansu Province. Based on the eddy correlation system, the evapotranspiration (ET) of the cabbage agroecosystem during the growth period was obtained and the main driving factors of ET changes were determined. The Root Zone Water Quality Model 2.0 version (RZWQM2 model) was used to simulate ET during the growth period. The results showed the following: (1) The ET of cabbage during the growth period was 260. 1 ± 24.2 mm, which was basically lower than other crops planted in this area. (2) Through partial correlation analysis and principal component analysis, it can be found that environmental and physiological factors jointly drive changes in ET. The main driving factors include gross primary productivity, net radiation, and water use efficiency. (3) The RZWQM2 model can simulate the ET of the cabbage agroecosystem well, especially in simulating the total ET value and its trend. The growth period ETs were 7.3% lower than the ETm. Cabbage is an important cash crop in Northwest China, and ET is an important component of the water cycle in the agroecosystem. Determining the main driving factors of ET is of great significance for the sustainable utilization of agricultural water resources in Northwest China. Our results can provide a scientific basis for the cultivation of cabbage as a cash crop and the development of water saving agriculture.

Ameliorating dilution of Cr and Ni and improving PWSCC resistance of 52 M overlay by hot wire plasma arc cladding

The multi-scale chemical composition distribution and microstructure of Alloy 52 M overlay on low alloy steel by hot wire plasma arc cladding (HWPC) were characterized. Stress corrosion cracking (SCC) growth rates were quantified in the dilution zone (DZ) near the fusion boundary and in the bulk of Alloy 52 M using compact tension samples with a thickened cladding overlay. The DZ of the Alloy 52 M side exhibited a single macroscopic dilution zone containing approximately 27–28 wt% Cr and 50 wt% Ni, in contrast to the multiple dilution zones observed in the DZ of Alloy 52 M overlays or joints prepared using other welding technologies such as submerged arc welding (SMAW). The DZ of the HWPC overlay exhibited less dilution of Cr and Ni compared to SMAW weldment. This resulted in a shorter average SCC band and fewer local intergranular cracks in the DZ of HWPC, as observed from SCC crack growth rate specimens tested in simulated PWR primary water at 325 °C and 350 °C. These findings highlight the advantages of utilizing HWPC to enhance SCC resistance in the DZ of Alloy 52 M overlays over conventional cladding technologies.

Climate change, seasonality and household water security in rural Gambia: A qualitative exploration of the complex relationship between weather and water

Climate change could pose a threat to water security for many communities, particularly in settings where rainfall patterns are becoming more varied and there is higher frequency of extreme events, such as heavy rainfall and droughts. Understanding how rainfall affects water security—including water access, water quality and water use behaviours—can inform investment in more climate-resilient infrastructure and safeguard against future health risks. This study aims to explore how households in rural Gambia experienced water security in relation to seasonal rainfall patterns and extreme weather events. Data collection focused on two communities (Kiang West and Basse) with differing access to water infrastructure, within which some villages had greater access to groundwater sources, such as solar-powered boreholes, and others primarily used uncovered wells. 46 participants were interviewed in Spring 2022 using multiple qualitative methods, including in-depth interviews and transect walks. We found that people’s experience of water security and rainfall (including seasonal rainfall, drought and heavy rainfall) was complex and varied according to the primary household water source. Both dry and rainy season posed challenges to household water security in terms of quality and quantity. Households with access to more resilient infrastructure, such as solar-powered boreholes, discussed a shift in the relationship between weather and water security, where they were less vulnerable to water shortages during dry conditions compared to those using wells. However, these sources did not fully resolve water security issues, as they experienced water shortages during cloudy conditions. Extreme weather events, such as heavy rainfall, heightened perceived water issues, as these events sometimes damaged water infrastructure and contaminated water sources. Seasonal workloads, that were higher in the rainy season, also jeopardised water security, as this limited time for water collection. Increased investment in infrastructure, maintenance, water-treatment and behavioural change is required to mitigate the risks.

Spatiotemporal Evolution and Driving Factors of Ecosystem Supply and Demand Bundles: A Case Study in the Sichuan-Yunnan Ecological Buffer Area, China

Identifying the spatial characteristics of ecosystem service (ES) supply and demand is crucial for effective ecosystem management and restoration. Past related studies have primarily focused on balancing ES supply and demand and supply clustering, with less attention focused on the drivers of demand clustering and their spatial evolution. This study explored the spatiotemporal supply–demand dynamics in four crucial ecosystem services (ESs) in the Sichuan-Yunnan ecological buffer area region between 2005 and 2019, namely water yield, net primary production, soil conservation, and habitat quality. Self-organizing maps and geographical detectors were used to classify supply–demand ES bundles as their main drivers, respectively. The main results of the study included: (1) A decline in habitat quality, whereas net primary productivity, water yield, and soil conservation increased. However, there were increasing demands for habitat quality, water yield, and net primary productivity, despite the decrease in demand for soil conservation. (2) Demand for habitat quality was met by supply, whereas there were deficits in soil conservation, water yield, and net primary productivity, which contributed to the demand in the east exceeding that elsewhere. (3) The proportion of ES bundle 2 increased, whereas those of the remaining ES bundles declined. Similarly, the areas of ES demand bundles (ESDBs) 1 and 4 decreased, whereas those of 2 and 3 increased. While the spatial extent of the ESBs remained relatively stable, those of the ESDBs in the northern regions increased. Key factors influencing the spatial distribution of ES supply include human activities, population density, and precipitation, whereas land use, population density, and the human activity index primarily affect demand distribution. The results of this study can act as a reference for comprehensive regional ecosystem management.

Geology and genesis of the Aqishan Pb-Zn deposit, NW China: Insights from mineralogy, geochemistry, and in situ U-Pb geochronology

The unique ore-forming processes and the key factors responsible for formation of skarn deposits are still obscure, and challenges exist in the determination of timing of Pb-Zn skarns owing to lacking suitable mineral chronometers. Here we present detailed paragenesis, bulk geochemistry, in situ U-Pb dating of zircon and garnet, and garnet oxygen isotopes together with in situ zircon Hf-O isotopes from the newly discovered Aqishan Pb-Zn deposit in the southern Central Asian Orogenic Belt (CAOB), northwest China. This comprehensive data set revealed a Late Carboniferous subduction-related distal Pb-Zn skarn system associated with the granitic magmatism. Pre-ore stage garnets are generally subhedral to euhedral with oscillatory zoning and show slightly fractionated rare earth element patterns with positive Eu anomalies that point to an infiltration metasomatism origin under high water/rock ratios. The syn-ore stage sphalerite is typically enriched in Mn and Cd and has moderate Zn/Cd ratios (337–482), with a formation temperature of 265 °C to 383 °C, which indicate magmatic-hydrothermal signatures. The isocons defined by P2O5 decipher that the principal factors for skarn formation were elevated activities of Fe, Ca, and Si species, where remobilization of Pb metals, meanwhile, contributed to ore-forming budgets to mineralizing fluids. SIMS U-Pb dating of zircons from granite porphyry that occurs distal to the skarns and Pb-Zn orebodies shows that these intrusions emplaced at ca. 311.3–310.6 Ma, recording the subduction of the Paleo-Tianshan oceanic plate. Hydrothermal garnets in close textural association with Pb-Zn sulfides yield indistinguishable in situ LA-ICP-MS U-Pb ages of 310.5 ± 4.1 Ma. Whole-rock geochemistry and in situ zircon Hf-O isotopes (δ18O = 4.6‰–6.0‰) indicate that the granite porphyry was derived from partial melting of juvenile crust and influenced by subducted oceanic crust. Oxygen isotope compositions of garnets (δ18O = 8.0‰–9.0‰) demonstrate that the equilibrated ore fluids were inherited from fluid-rock interactions between a primary magmatic water and host tuff rocks. Our study highlights the application of garnets as a potential robust U-Pb geochronometer and isotopic tracer of ore fluids in skarn mineralizing systems in subduction-related arc environments.

Willingness to Pay for Watershed Services by Downstream Water Users in Babati District, Tanzania

Payment for Ecosystem Services promotes watershed management through Payment for Watershed Services. It encourages improved land management practices in upstream areas to enhance the quantity and quality of water downstream. The Nou Forest Reserve in Babati district covers Lake Manyara's headwaters. Its rivers are the primary water source for the area's inhabitants. However, there have been reports of declining water quality and quantity, presenting an opportunity to introduce payment for watershed services for Nou Forest Reserve conservation and management. The present study was conducted to assess the level of awareness among downstream water users about the importance of watersheds in providing sustainable water supply. Using the Contingent Valuation Method, the study estimated the communities’ willingness to pay for improved watershed services, analysed factors influencing capacity to pay, and examined possible operational modes for implementing payment mechanisms. A total of 155 domestic water users and 50 non-domestic water users were interviewed. It was found that 71% of domestic water users and 82% of non-domestic water users were willing to pay for improved watershed services, with a mean willingness to pay estimated at TAS 1261 per user/year for domestic water users and TAS 112322 per user/year for non-domestic water users. Factors such as gender, occupation, education, and farm size significantly (P<0.05) influenced water users' willingness to pay. Income was a significant factor in the willingness to pay for non-domestic water users, but it was not significant for domestic water users. The current study suggests that downstream water users in Babati district, who act as watershed service buyers, could collect a water user fee based on estimated amounts. This approach would help address declining water quality and quantity through improved watershed management and thus enhance watershed conservation and management.

Modification of a hybrid fluoro-surfactant containing double fluorocarbon chains on the carbonate and shale rocks for the wettability reduction of water and oil

An original hybrid fluoro-surfactant DHE with double fluorocarbon chains was synthesized. This surfactant aimed to reduce significantly the wettability of water and oil on the carbonate and shale rocks and adapt to the high salinities of the formation water. This could enhance the imbibition and injection of water in the matrix of carbonate reservoirs and the fracturing flowback in shale reservoirs. DHE showed good interface activities in salt-free and brine solutions, and remarkable water- and oil-wettability reduction on the two kinds of rocks. Moreover, its tolerant-NaCl concentrations were not below 80 g/L. The diameters of DHE mono-molecules were 1.5–4 nm and innumerable worm-like micelles were observed by TEM at the critical micelle concentration of 1.2 g/L in water. After being modified only using the 0.03 g/L DHE saline with 30 g/L NaCl for the carbonate rock, the surface energy was reduced substantially, so the primary water- and oil-wetting (θ: 43–50.6°) on the rock changed to nearly intermediate wetting (θ: 85.0−87.4°), which was the most ideal wetting state for oil and gas production in reservoirs. Moreover, the modifying effect of DHE on the rocks became stronger with the DHE and salt concentrations in the DHE brines. Therefore, it was found that the capillary pressure could be changed to zero using very small amounts of hybrid fluoro-surfactants such as DHE because the rocks could be altered to intermediate wetting for water and oil phases. Consequently, the oil recovery in the water-flooding of carbonate reservoirs and the fracturing flowback in shale reservoirs would be improved significantly.

Soil environmental anomalies dominate the responses of net ecosystem productivity to heatwaves in three Mongolian grasslands

Climate change is causing more frequent and intense heatwaves. Therefore, it is important to understand how heatwaves affect the terrestrial carbon cycle, especially in grasslands, which are especially susceptible to climate extremes. This study assessed the impact of naturally occurring, simultaneous short-term heatwaves on CO2 fluxes in three ecosystems on the Mongolia Plateau: meadow steppe (MDW), typical steppe (TPL), and shrub-grassland (SHB). During three heatwaves, net ecosystem productivity (NEP) was reduced by 86 %, 178 %, and 172 % at MDW, TPL, and SHB, respectively. The changes in ecosystem respiration, gross primary production, evapotranspiration, and water use efficiency were divergent, indicating the mechanisms underlying the observed NEP decreases among the sites. The impact of the heatwave in MDW was mitigated by the high soil water content, which enhanced evapotranspiration and subsequent cooling effects. However, at TPL, insufficient soil water led to combined thermal and drought stress and low resilience. At SHB, the ecosystem's low tolerance to an August heatwave was heavily influenced by species phenology, as it coincided with the key phenological growing phase of plants. The potential key mechanism of divergent NEP response to heatwaves lies in the divergent stability and varying importance of environmental factors, combined with the specific sensitivity of NEP to each factor in ecosystems. Furthermore, our findings suggest that anomalies in soil environment, rather than atmospheric anomalies, are the primary determinants of NEP anomalies during heatwaves. This challenges the conventional understanding of heatwaves as a discrete and ephemeral periods of high air temperatures. Instead, heatwaves should be viewed as chronologically variable, compound, and time-sensitive environmental stressors. The ultimate impact of heatwaves on ecosystems is co-determined by a complex interplay of environmental, biological, and heatwave features.

Thermal Performance of Conventional-Metal and Novel-Plastic Drain Water Heat Recovery Device

Drain water heat recovery (DWHR) systems are effective for reducing energy consumption by capturing waste heat from drain water and using it to preheat the primary water supply in buildings. However, traditional DWHR devices, with copper helical tubes wrapped around a central pipe, can be expensive for residential use, deterring homeowners. This study introduces an innovative 3D-printed DWHR design using Nylon PA material. This design eliminates contact and conduction resistances of helical tubes, resulting in reduced thermal resistance, weight, manufacturing cost, and improved performance. Experimental testing compares the new plastic DWHR device with the conventional metal one under steady and transient conditions. In addition, detailed heat transfer models and thermal networks are given for both devices. The plastic device consistently outperforms the metal one, achieving higher effectiveness within the first few minutes of operation across various water flow rates. This advantage is particularly beneficial for short-term drain water usage like sinks and showers. Additionally, the novel DWHR device maintains a 16–20% higher steady-state effectiveness at high flow rates. This innovative approach promises cost-effective and efficient heat recovery, making DWHR technology more accessible for residential and commercial applications.

An Empirical Predictive Model for Atmospheric H Lyman‐α Emission Brightness at Mars

AbstractCharacterizing the abundance of atmospheric hydrogen (H) at Mars is critical for determining the current and, subsequently, the primordial water content on the planet. At present, the atmospheric abundance of Martian H is not directly measured but is simulated using proprietary models that are constrained with observations of H Lyman‐α emission brightness, as well as with observations of other atmospheric parameters, such as temperature and Solar UV irradiance. Publicly available brightness measurements require further processing to have scientific utility. To make the data needed to model H abundances and escape rates more accessible to the community, we use H Lyman‐α emissions made with the Mars Atmosphere and Volatile Evolution (MAVEN) mission. The near decade‐spanning data set is reduced to obtain disk‐pointed averages of the H brightness in the upper atmosphere of Mars and then analyzed for statistical trends across multiple variables. The H Lyman‐α emission brightness is found to be dependent on Solar illumination, Solar cycle, and season. The resulting data trends are used to derive empirical fits to build a predictive framework for future observations or an extrapolative tool for estimates of water content at previous epochs. Data that was intentionally not included in the empirical derivations are used to validate the predictions successfully to within 18% accuracy, on average. This first‐of‐its kind predictive model for H brightness is presented to the community and can be used with atmospheric models to further derive and interpret the abundances and escape rate of H atoms at Mars.

New Advances in Rainwater Harvesting and Treatment

Rainwater harvesting is an ancient water supply practice that still provides a primary water source for a large proportion of the world’s population [...]

Enhancing the treatment of Staphylococcus aureus infections: A nanosystem with including dual antimicrobial peptide

The unique properties of nanoparticles (NPs) and their modification to selectively target infected tissues or specific pathogens could be an effective approach to revolutionize the treatment of infectious diseases. The objective of this study was to develop poly (lactic-co-glycolic acid) (PLGA) nanoparticles loaded with an antimicrobial peptide (HF-18) and decorated with an antimicrobial peptide (P6.2) for selective targeting against Staphylococcus aureus (S. aureus). Applying the Box-Behnken experimental design, HF-18 loaded PLGA nanoparticles were produced and optimized to have minimum particle size and polydispersity index (PDI) value by selecting primary water phase volume, organic phase volume and secondary water phase volume as independent parameters. Secondary water phase volume had the most significant effect on particle size and PDI. OPT-NP was more effective than HF-18 against most bacterial strains. The non-targeted (OPT-NP) and targeted (P6.2-OPT-NP) systems were shown to be biocompatible at levels that exhibited antibacterial activity. The P6.2-OPT-NP was predominantly taken up by S. aureus, while Escherichia coli (E. coli) used as a negative control showed minimal uptake. Furthermore, co-culture studies indicated that P6.2-OPT-NP was drastically uptake by S. aureus, while no internalized nanoparticles were visualized in fibroblast cells indicating active targeting of bacterial cells by P6.2-OPT-NP. Thus, these findings demonstrate the development of a formulation that selectively targets S. aureus, presenting promising prospects for future therapeutic applications.

Importance of Changes in the Copper Production Process through Mining and Metallurgical Activities on the Surface Water Quality in the Bor Area, Serbia

This paper considers the impact of copper mining-influenced water and metallurgical wastewater on the surface water in the Bor area, Serbia. Sampling, realized through the four campaigns (2020–2021), confirmed that both types of water, discharged without appropriate treatment in the Bor River, had a signific impact on the concentration of metal ions, pH and electrical conductivity on the watercourse in the Bor area. The highest concentrations of the following metal ions, Cu—271 mg/L, As—25,991 μg/L, Ni—13,856 μg/L, Cd—2627 μg/L, and Pb—2855 μg/L, were registered in the metallurgical wastewater samples. After changes occurred in the copper production process by stopping the discharge of untreated wastewater into the Bor River, the concentrations of monitored elements were drastically decreased. In the period 2022–2024, the concentration values for Cu, As and Pb ions were below the maximum allowable value, and the concentration values of Ni and Cd ions were also decreased. The values for pH and electrical conductivity were in the maximum allowable range. The return of wastewater to the copper production process would lead to both a reduction in the primary water consumption and reduction in the negative impact on the environment.

The Extent to Which the Available Water Resources in Upper Egypt Can Be Affected by Climate Change

Over the past two decades, rapid climate change has severely impacted people’s lives globally, affecting their safety and sustainability. Water, a vital human resource, has been severely affected, with drought and high temperatures leading to desertification, the drying up of rivers and lakes, spontaneous fires in forests, and massive floods and torrents due to melting ice and rising sea and ocean surface water levels. The expected impacts of climate change on the Nile, Egypt’s primary water source, are significant. These impacts can vary across regions, depending on factors like local climate, socio-economic dynamics, topography, and environmental nature. Upper Egypt, characterized by arid and semi-arid regions, faces water scarcity and socio-economic development challenges. Climate change exacerbates these issues, posing significant threats to the region’s ecological sustainability and socio-economic development. Therefore, it is crucial to address these impacts to ensure the Nile’s continued vitality and sustainability. The study aims to analyze the climate change data over the past few decades, analyze its characteristics, and model its effects on Upper Egypt’s water sources. The study expected a big decrease in the water resources of the Nile. While what is currently occurring in terms of fluctuating rainfall rates between scarcity and severity contradicts the results of those studies, that is the best evidence of the need for further research and studies to obtain more reliable and consistent results with the reality that it may help decision-makers to develop scenarios to manage climate change effectively, preventing or reducing negative effects, and finding suitable alternatives. Studies predict a 10% decrease in Nile revenue at Aswan High Dam Lake by 2095, with some predicting a 30% increase. This lack of credibility underscores the need for more comprehensive studies.

Estimation of residual stress in dissimilar metals welding using deep fuzzy neural networks with rule-dropout

Welding processes are used to connect several components in nuclear power plants. These welding processes can induce residual stress in welding joints, which has been identified as a significant factor in primary water stress corrosion cracking. Consequently, the assessment of welding residual stress plays a crucial role in determining the structural integrity of welded joints. In this study, a deep fuzzy neural networks (DFNN) with a rule-dropout method, which is an artificial intelligence (AI) method, was used to predict the residual stress of dissimilar metal welding. ABAQUS, a finite element analysis program, was used as the data collection tool to develop the AI model, and 6300 data instances were collected under 150 analysis conditions. A rule-dropout method and genetic algorithm were used to optimize the estimation performance of the DFNN model. DFNN with the rule-dropout model was compared to a deep neural network method, known as a general deep learning method, to evaluate the estimation performance of DFNN. In addition, a fuzzy neural network method and a cascaded support vector regression method conducted in previous studies were compared. Consequently, the estimation performance of the DFNN with the rule-dropout model was better than those of the comparison methods. The welding residual stress estimation results of this study are expected to contribute to the evaluation of the structural integrity of welded joints.

Water deficit differentially modulates leaf photosynthesis and transpiration of fungus-tolerant Muscadinia x Vitis hybrids.

Screening for drought performance among novel fungi-tolerant grapevine genotypes is a key point to consider in semiarid regions where water scarcity is a common problem during fruit ripening period. It is therefore important to evaluate the genotypes' responses at the level of carbon metabolism and water demand, under water deficit conditions. This study aimed to characterize leaf and plant water use efficiency (respectively named WUEi and WUEpl) of novel INRAE fungi-tolerant genotypes (including LowSugarBerry (LSB) genotypes), under mild and high-water deficit (WD) and to decipher the photosynthetic parameters leading to higher WUEi. For this purpose, experiments were conducted on potted plants during one season using a phenotyping platform. Two stabilized soil moisture capacity (SMC) conditions, corresponding to mild (SMC 0.6) and high (SMC 0.3) WD, were imposed from the onset of berry ripening until the physiological ripeness stage, which was defined as the point at which fruits reach their maximum solutes and water content. At the whole plant level, all genotypes increased WUEpl under high WD. The highest WUEpl was reached for 3176N, which displayed both a high rate of non-structural carbon accumulation in fruits due to high fruit-to-leaf ratio and low plant transpiration because of low total leaf area. However, when normalizing the fruit-to-leaf ratio among the genotypes, G14 reached the highest normalized WUEpl_n under high WD. At the leaf level, WUEi also increased under high WD, with the highest value attained for G14 and 3176N and the lowest value for Syrah. The higher WUEi values for all genotypes compared to Syrah were associated to higher levels of photosynthesis and changes in light-harvesting efficiency parameters (ΦCO2, qP and qN), while no clear trend was apparent when considering the photosynthetic biochemical parameters (Vcmax, Jmax). Finally, a positive correlation between leaf and plant WUE was observed regardless of genotypes. This study allowed us to classify grapevine genotypes based on their grapes primary metabolite accumulation and water consumption during the critical sugar-loading period. Additionally, the study highlighted the potential drought adaptation mechanism of the LSB genotypes.

A pentametallic high-entropy mixed-dimensional mesoporous heterostructure for azo-dye wastewater degradation and decolorization

The degradation and decolorization of azo-dyes wastewater require more efficient methodologies to reduce this primary water pollution source. Herein, we developed a pentametallic (Au-Ti-Mg-Al-Cu) high-entropy mixed-dimensional mesoporous heterostructure (HEMDMHs) for azo-dye wastewater degradation and decolorization. This HEMDMHs structure was constructed by irregularly growing nanoscale Mg-Al-Cu layered-double-hydroxide (LDH) onto micro-scaled 2-dimensional (2D) Ti3C2Tx MXene and then in-situ synthesizing ultrasmall (<3 nm) 0-dimensional (0D) gold nanoclusters (AuNCs) onto the LDH/MXene mesoporous support. This Au-Ti-Mg-Al-Cu HEMDMHs can efficiently degrade azo-dyes wastewater within 2 min, producing colorless and clear solutions. This exceptional performance can be achieved across a wide pH range of 2 to 12 and temperatures ranging from 0 to 60 °C under sunlight. Furthermore, this HEMDMHs can be easily recoverable through centrifugation for reuse. Mechanistic investigation revealed a synergistic mechanism in which the mesoporous LDH/MXene enhances physical absorption of azo-dyes, while the AuNCs/LDH heterostructure promotes their chemical degradation. Considering its high decolorization activity, high cycle stability, reusability and controllable economic cost, our results provide a promise HEMDMHs candidate for the treatment of azo-dye wastewater.

Representative High-Temperature Hydrothermal Activities in the Himalaya Geothermal Belt (HGB): A Review and Future Perspectives

Southern Tibet and western Yunnan are areas with an intensive distribution of high-temperature geothermal systems in China, as an important part of the Himalayan Geothermal Belt (HGB). In recent decades, China has conducted systematic research on high-temperature geothermal fields such as Yangbajing, Gudui, and Rehai. However, a comprehensive understanding has not yet been formed. The objective of this study was to enhance comprehension of the high-temperature geothermal system in the HGB and to elucidate the hydrogeochemical characteristics of geothermal fluids. This will facilitate the subsequent sustainable development and exploitation of domestic high-temperature hydrothermal geothermal resources. To this end, this study analysed geothermal spring and borehole data from the Yangbajing, Gudui, and Rehai geothermal fields. Based on previous research results, the source, evolution, and reservoir temperature characteristics of geothermal fluids are compared and summarised. The main high-temperature geothermal water in the geothermal field is derived from the deep Cl-Na geothermal fluid. Yangbajing’s and Gudui’s geothermal waters are primarily recharged by snow-melt water, while Rehai’s geothermal water is mainly recharged by local meteoric water. The average mixing ratios of magmatic water in the Yangbajing, Gudui, and Rehai geothermal fields are 17%, 21%, and 22%, respectively. The Yangbajing and Gudui geothermal fields have a relatively closed geological environment, resulting in a stronger water–rock interaction compared to the Rehai geothermal field. As geothermal water rises, it mixes with shallow cold water infiltration. The mixing ratios of cold water in the Yangbajing, Gudui, and Rehai geothermal fields are 60–70%, 40–50%, and 20–40%, respectively. Based on the solute geothermometer calculations, the maximum geothermal reservoir temperatures for Yangbajing, Gudui, and Rehai are 237 °C, 266 °C, and 282 °C, respectively. This study summarises and compares the hydrogeochemical characteristics of three typical high-temperature geothermal fields. The findings provide an important theoretical basis for the development of high-temperature geothermal resources in the Himalayan Geothermal Belt.

Nb speciation and microstructural characterization of the oxide layer formed on neutron-irradiated Zr-2.5 Nb alloy in high-temperature water

It is crucial to understand the degradation mechanisms of the alloy Zr-2.5 Nb, which make the pressure boundary in Canada Deuterium Uranium reactors. In the present study, Zr-2.5 Nb coupons were exposed for 567 days at 325 °C with and without neutron-irradiation in simulated primary water chemistry. A combination of scanning/transmission electron microscopy with energy dispersive X-ray spectroscopy, and electron energy loss spectroscopy was used to investigate the base metal and oxide. The obtained results suggest that the distribution of nanopores and the variation in Nb oxidation state likely create a gradient in the oxygen concentration and electrochemical potential through the film.

Water-Filling Characteristics and Water Source of Weakly Rich Water and Weakly Conducting Water Aquifers in the Changxing Formation after Mining Damage

The escalation of mining activities in the karst regions of Guizhou Province has heightened the occurrence of water-inrush incidents in deep coal mines. This study focused on water-inrush phenomena within the Xinhua mining area of Jinsha County, Guizhou Province, aiming to investigate the sources of these incidents. The findings indicated that the overlying limestone of the Changxing Formation in the coal seam served as a vulnerable aquifer under certain conditions, leading to water inrushes. The analysis of the spatiotemporal distribution patterns of water-inrush incidents at the working face indicated that previous mining operations damaged the shallow Changxing Formation limestone, resulting in the accumulation of goaf water and the formation of numerous mining-induced fractures. These fractures served as rapid conduits for water inrushes from both atmospheric precipitation and underground sources at the deep working face. The examination of surface water and mine water quality demonstrated that both exhibited similar characteristics, predominantly featuring bicarbonate, sulfate, and sodium compositions. Investigation into the relationship between mine water inflow and atmospheric precipitation established that atmospheric precipitation influenced the mine water supply cycle, with a replenishment period of ~10 months during the operational phase of the Jinyuan Coal Mine and about one month post-closure. The fractures induced by mining activities within the Changxing Formation limestone facilitated water flow, with atmospheric precipitation serving as the primary water source for the mine. This study offered a valuable scientific foundation for addressing water-related damage resulting from atmospheric precipitation in mines susceptible to water inrushes under analogous hydrogeological conditions.