Main Ions Research Articles

Evolution of Physical and Chemical Characteristics of Atmospheric Precipitation and Its Significant Impacts on the Environment in Beijing

Atmospheric precipitation samples were collected in 2018, 2019, and 2021 in Beijing to study the concentrations and changes of the main metal elements and water-soluble ions； the wet deposition fluxes of heavy metals, water-soluble ions, dissolved inorganic nitrogen, and sulfur in the atmospheric precipitation and their impacts on the ecological environment； and the scavenging mechanisms of the typical precipitation to atmospheric pollutants during the study period. The results showed that the precipitation in Beijing during the study period was mostly neutral or alkaline, and the frequency of acid rain occurrence was very low, only accounting for 3.06%. The total concentrations of major metal elements in 2018, 2019, and 2021 were （4 787.46 ±4 704.31）, （7 663.07 ±8 395.05）, and （2 629.13 ±2 369.51） μg·L-1, respectively. The total equivalent concentrations of ions in 2018, 2019, and 2021 were （851.68 ±649.16）, （973.98 ±850.94）, and （644.31 ±531.16） μeq·L-1, respectively. The interannual changes in major metal elements and ions followed the order of 2019 > 2018 > 2021. The seasonal average total concentrations of major metal elements in spring, summer, autumn, and winter were （9 624.25 ±7 327.92）, （4 088.67 ±5 710.14）, （3 357.68 ±3 995.64）, and （6 203.19 ±3 857.43） μg·L-1, respectively, and the seasonal average total equivalent concentrations of ions in spring, summer, autumn, and winter were （1 014.71 ±512.21）, （729.83 ±589.90）, （724.35 ±681.40）, and （1 014.03 ±359.67） μeq·L-1, respectively, all presenting the order of spring > winter > summer > autumn. NO3- and SO42- were the main acid-causing ions in precipitation, whereas NH4+ and Ca2+ were the main acid-neutralizing ions. The wet deposition fluxes of the heavy metal Cd were very low [（0.05 ±0.01） mg·（m2·a）-1], only accounting for （0.13 ±0.04）% of the total wet deposition fluxes of main metal elements； however, its soil safety years were 291 years, significantly lower than those of other heavy metals, displaying that its ecological risk was relatively the highest. The total wet precipitation flux of water-soluble ions NH4+, Ca2+, NO3-, and SO42- accounted for （85.72 ±2.18）% of the wet precipitation flux of total ions, suggesting that their comprehensive impact on the ecological environment might have been higher. DIN wet deposition flux was mainly characterized by NH4+-N, which had a positive impact on the ecological environment in summer. SO42--S wet deposition flux was higher in summer, so its positive impact on the ecological environment was also greater. The scavenging effects of atmospheric precipitations to pollutants from the air were impacted by various factors, and the synergism effects of these factors could directly influence the scavenging mechanisms of precipitation to pollutants.

Water chemical formation mechanism and water quality analysis of Shichuan River under the influence of human activities

ABSTRACT It is necessary to analyze the characteristics of the water environment and factors influencing the basin in order to determine its current ecological status. This study aims to investigate the chemical properties in the Shichuan River Basin using Gibbs diagram, Piper triangle diagram, correlation analysis, factor analysis, and main ion ratio method. The enhanced Nemerow comprehensive index method and fuzzy comprehensive evaluation method are employed for river water quality assessment. The findings reveal that runoff water has a weak alkaline nature with low salinity. The hydrochemical type of river water includes Ca2++Mg2++Na+-SO4 2-, Ca2++Mg2+-SO4 2-+Cl-+HCO3 -, Ca2++Na+-SO4 2-+Cl-+HCO3 -. Silicite and dolomite weathering are identified as primary influencing factors, while evaporite weathering also contributes to variations in chemical composition within the basin's waters. Ca2+, Mg2+, SO4 2- and HCO3 - originate from carbonate rock and silicate rock weathering processes, whereas Na+, K+ and Cl-, are primarily derived from evaporite weathering influenced by domestic sewage and agricultural activities. Agricultural production practices along with discharge of domestic sewage have an impact on Na+, K+, Cl- and NO3 -concentrations in aquatic systems. Water quality at all three monitoring sections falls under level IV classification. Phosphorus emerges as a key limiting factor for eutrophication within this basin's watersheds.

Wood flour and kraft lignin enable air-drying of the nanocellulose-based 3D-printed structures

The predominant technique for producing 3D-printed structures of nanocellulose involves freeze-drying despite its drawbacks in terms of energy consumption and carbon footprint. This study explores the less-energy-intensive drying approach by leveraging the valorization of forest residual streams. We utilized wood flour and Kraft lignin as fillers to facilitate room-temperature drying of the nanocellulose-based 3D printed structures. Various ink formulations, integrating cellulose nanofibers, wood flour, and lignin, were tested for direct ink writing (DIW). The formulations exhibited shear-thinning behavior and distinct yield stress with rising stress levels, ensuring the effective flow of the ink during DIW. Consequently, multilayered objects were printed with high shape fidelity and precise dimensions. Lignin and wood flour prevented structural collapse upon room-temperature drying. A reduced shrinkage was observed with the addition of lignin in freeze and room temperature drying. Moreover, the room-temperature dried samples were denser and demonstrated significantly higher resistance to applied compressive force, surpassing those reported for cellulose-based 3D composites in the existing literature. Remarkably, the trade-off effects of lignin are highlighted in terms of efficient stress-distributing and micro-scale sliding, enabling better strength. Along with wood flour, it further increases thermal stability. However, lignin hinders the hierarchical porous structure, the main ion transportation channels, reducing the double-layer capacitance of the carbonized structures. Overall, the results underscore the potential of all-biobased formulations for DIW for practical applications, highlighting their enhanced mechanical properties and structural integrity via the more sustainable drying method.

Hydrogeochemistry and human health risk assessment of heavy metal pollution of groundwater in Tarkwa, a mining community in Ghana

The current study investigated the geochemical characterization and contamination of groundwater quality in Tarkwa, a mining community in Ghana. Total dissolved solids, electrical conductivity, calcium, magnesium, sodium, potassium, total dissolved solids, total hardness, heavy metals, and cyanide (CN) were all assessed in 74 groundwater samples. Other parameters assessed included pH, electrical conductivity, carbonate, bicarbonate, chloride, sulphate, nitrate, and pH. Using the method recommended by the USEPA, a health risk assessment was carried out. Among the parameters which exceeded their WHO recommended threshold were pH (4.9–7.7), Conductivity (150–1082 µS/Cm), Turbidity (1.4–139.5 NTU), Magnesium (1.9–395.5 mg/L), Nitrate (4.5 mg/L–760 mg/L), phosphate (2.3–80 mg/L), Sulphate (10–855.6 mg/L), CN (1.6–16 mg/L), As (0.001–0.015 mg/L), Hg (0.001–0.005 mg/L), Cd (ND-0.009 mg/L), Mn (0.004–1.38 mg/L), Ni (0.002–0.118 mg/L). The study also showed that the groundwater in Tarkwa is naturally hard, making Ca and Mg ions the main ions determining the chemistry of the water. Similar to this, the most significant factors affecting water chemistry were rock dominance and precipitation dominance. Due to high levels of CN, As, and Cd, health risk evaluation revealed that prolonged intake of groundwater from Tarkwa is linked to both carcinogenic and noncarcinogenic health risk. Children were shown to be more vulnerable to both carcinogenic and noncarcinogenic health risks than adults.

Novel data interpretation method for DIII-D divertor retarding field energy analyzer with 3-D particle-in-cell simulations.

A novel data interpretation process that utilizes comprehensive particle-in-cell (PIC) simulations is developed for the new retarding field energy analyzer (RFEA) currently being constructed at DIII-D for the lower divertor using the Divertor Material Evaluation System. This probe is expected to survive a heat load of up to 100 MW/m2 for up to 5s and reliably measure the main ion temperature (Ti) on the divertor target ranging from 10 to 200 eV. These extreme conditions posed significant engineering limitations on the probe geometry, thus extensive validation work has been performed. The conventional fitting method for the RFEA I-V characteristics is based on a simplified 1-D model without considering the ion space charge inside the probe cavity and may not be sufficient for probes designed for the DIII-D divertor environment. In this article, a more realistic description of the particle propagation process within the RFEA cavity is achieved by including both 3-D geometric effects and ion space charge in the PIC simulations, and the capability to reconstruct the ion energy distribution functions is demonstrated with reasonable consistency.

Construction of carbon coated spherical Zn0.71Mn0.29Se@C for high-performance aluminum ion batteries

As a high energy density material, selenides have shown highly competitive initial capacity when applied to the positive electrode of aluminum ion batteries. However, in acidic electrolytes, the volume effect of selenides during electrochemical reactions can cause damage to the material structure. In long-term cycling tests, the performance of selenide cathode materials deteriorates rapidly, which greatly limits the application of this high-performance material in aluminum ion batteries. Here, Zn0.71Mn0.29Se@C material was synthesized for the cathode of aluminum ion batteries, which is covered by a carbon layer on the sphere shells and has good crystallinity. Zn0.71Mn0.29Se@C showed excellent performance: the capacity was maintained at 102.79 mAh/g after 2000 cycles. Attributed to the supporting effect of the carbon material, Zn0.71Mn0.29Se@C exhibits excellent structural stability. During charging and discharging, the carbon layer of the sphere shell effectively limits the volume expansion and improves the cycling performance of the battery. Meanwhile, the simulation results show that the Zn0.71Mn0.29Se@C material has a strong trapping effect for AlCl4− ions. As the main ion involved in the reaction, this strong interaction can greatly improve the reaction kinetics. On the other hand, the charge accumulation caused by the embedding of potential ions enhances the charge transfer. In conclusion, the carbon layer in the outer layer of Zn0.71Mn0.29Se@C not only supports the sphere structure, but also enhances the trapping effect for potential ions, and this novel electrode material is expected to improve the application prospect of aluminum ion batteries.

Morphological and physiological features of genotypes of Zea mays towards salt tolerance influenced by mycorrhizal fungi

Soil salinity poses a significant constraint on plant growth and productivity of maize. Salinity causes reduction in water content in plant tissues, ultimately reducing the photosynthetic capacity and resulting in decreased productivity. Normally in saline soils, chloride ions (Cl−) are particularly considered toxic to certain crops, but in case of maize, sodium ion (Na+) is the main ion responsible for toxicity due to its competition with K+ for binding sites at the plasma membrane. Mycorrhizoremediation which is an enhanced form of phytoremediation is one of the key players in remediation saline soils. Inoculation of these beneficial arbuscular mycorrhizae fungi can alleviate growth inhibition and the adverse effects of salinity in both halophytes and glycophytes by establishing symbiotic relationships with plants. AM fungi colonize the roots of maize plants, perform a crucial role in nutrient cycles in terrestrial ecosystems and own highly efficient and various mitigation mechanisms. Under saline conditions, AM fungi restrict the absorption and translocation of Na+ to shoot tissues and enhance the uptake of K+ in plants. An experiment aiming to enhance salt tolerance in maize through AMF symbiosis was conducted. In this experiment three AMF were evaluated at two salinity levels 66 mM and 100 mM. analysis of data revealed that AMF Ri collect showed showed highest percentage of root colonization at all salinity levels. While plants inoculated with AMF Ce CdG showed highest shoot and root biomass. Furthermore, plants inoculated with Sc CdG and Ce CdG showed a significant reduction in Na+ accumulation and enhance K+ accumulation in shoot and root tissues as compared to non-mycorrhizal plants.

Luminescence and thermometry sensing of Sr2InTaO6: Eu3+, Mn4+ phosphors in a wide temperature range

Fluorescent temperature sensing materials are generally designed based on the phenomenon that the fluorescence intensity ratio (FIR) of luminescence at different wavelength positions changes linearly with temperature. Luminescence at different wavelength positions can come from two different luminescent centers. The key to the design of such materials is that the two luminescent centers have different degrees of change with temperature, that is, they have different thermal quenching behavior. Herein, we have investigated the luminescence properties and structure of Eu3+ and Mn4+ co-doped in Sr2InTaO6. The emission of doped Eu3+ (rare earth) changes little with the increase of temperature. However, the emission of doped Mn4+ (transition metal) decreases sharply with increasing temperature. Materials in two different temperature ranges (80–300 K under room temperature, and 300–523 K above the room temperature) have shown a satisfactory temperature sensing performance. This work points out a direction for the design of temperature sensing materials based on the FIR of two luminescent centers, that is, mixing an ion with excellent luminescence thermal stability (such as rare earth ion Eu3+, Sm3+, Dy3+, etc.) as a reference, and an ion with relatively poor luminescence thermal stability (such as transition metal Mn4+, main group element ion Bi3+, etc.) as the temperature scale.

Ecophysiological and nutritional characterisation of two morphotypes of Cakile maritima subsp. maritima Scop. from Puglia region, Southern Italy.

Cakile maritima subsp. maritima Scop. (sea rocket) is a succulent halophyte with significant potential as a nutritious food source, being rich in essential nutrients such as vitamins, minerals, and antioxidants. This annual species exhibits two distinct leaf morphotypes: entire lamina (EL) and pinnatifid lamina (PL). Our understanding of their ecophysiological and nutritional profiles is still limited. The present study investigated the wild EL and PL sea rocket plants from southern Italy during their vegetative stage. The bio-morphological traits (leaf mass area-LMA, dry matter and chlorophyll concentrations), main inorganic ions, key antioxidants (carotenoids, anthocyanins, phenols, flavonoids, glucosinolates, vitamin C as ascorbic and dehydroascorbic acid), and antioxidant activity (by FRAP, DPPH, ABTS assays) were analyzed. Additionally, photosynthetic gas exchange and chlorophyll fluorescence were measured. PL plants showed thicker leaves (higher LMA) and greater accumulation of photo-protective pigments (carotenoids and anthocyanins), despite similar chlorophyll levels. The PL plants also demonstrated higher photosynthetic activity, transpiration rates, and stomatal conductance, with reduced non-photochemical quenching. The EL morphotype had higher cation (K, Mg, Ca, Na) and vitamin C (135.3 mg 100 g-1 FW) concentrations, while no significant disparities were observed between the morphotypes in phenolic concentration (208.5 mg g.a.e. 100 g-1 FW), flavonoids (71.5 mg q.e. 100 g-1 FW), or glucosinolates (61 mg g-1 FW). Interestingly, while the EL type had higher vitamin C, the PL morphotype showed superior antioxidant activity (FRAP, DPPH) and seems to be better adapted to water/nutrient scarcity typical of southern Italy. Both morphotypes offer potential as high-nutritional foods, however, future research should investigate the genotype-specific production of antioxidant compounds in EL and PL plants in response to environmental stresses, including salinity for potential exploitation as a new crop.

Characterization of aerosol and its oxidative potential in a coastal semi-rural site of Southern Italy

Considering the scarce number of studies investigating the oxidative potential of PM2.5 in Italy, a measurement campaign was conducted from February 2020 to October 2020 in a coastal semi-rural site of Basilicata (Southern Italy) with the goal to characterize the fine fraction of ambient particulate matter (PM) and investigate its chemical and toxicological properties, by means of oxidative potential. Different instruments such as an automatic low-volume sampler, an aethalometer and an optical particle counter, were employed for the measurement of PM2.5 mass concentration, equivalent black carbon (eBC) concentration and absorption Ångström exponent (AAE), and particle number size distribution in 0.25–31 μm size range, respectively. 108 daily PM samples, collected on quartz fibre filters, were chemically analysed. Organic (OC) and elemental (EC) carbon content was estimated by thermo-optical transmittance technique (TOT), the concentrations of the main water-soluble ions and total elements were determined by ion chromatography and ED-XRF technique, while the oxidative potential of the water-soluble fraction was estimated through the dithiothreitol (DTT) assay. The mean value of PM2.5 mass concentration was 9.2 ± 2.5 μg/m3 and the average contribution of measured species on PM2.5 mass was 3.3% EC; 19.3% OC; 27.0% secondary inorganic aerosol (sum of SO42−, NH4+ and NO3−), and 10.2% of the other ions and elements. The OC and EC contributions to PM2.5 mass and their mean ratio (OC/EC = 6.6 ± 3.1) suggest that the site is affected by the combined contribution of traffic emissions and biomass combustion (domestic heating and agricultural activities), with the latter prevailing over the traffic, as supported by the mean AAE value of 1.3. The mean OP normalized by sampled volume, OPDTTV, was as high as 0.34 ± 0.22 nmol/min·m3, a value comparable to those recorded for PM2.5 in suburban areas of Italy. The correlation between OPDTTV and the chemical species observed in the PM2.5 samples showed a good agreement with the carbonaceous component OC (r = 0.62) and with some ions, K+ and SO42− (r = 0.60). These results identify combustion sources as the most responsible for the relatively high OPDTTV activity of PM2.5 recorded in this area.

ICRH-related impurity source and control across experiments in H, D, T plasmas at JET-ILW

The experimental and theoretical analysis were focused on experiments conducted to assess the effect of plasma isotopes, protium (H), deuterium (D), and tritium (T) on ion cyclotron resonance heating (ICRH) related plasma wall interactions. Comparison of L-mode discharges with N = 1 3He and N = 1 H minority ICRH heating scenarios were done for different isotopes. For the selected pulses, the behaviour of high-Z, mid-Z and low-Z intrinsic impurity and radiated power behaviour was investigated based on data from VUV, visible spectroscopy, and bolometry diagnostic at Joint European Torus. It was found that for N = 1 3He scenario during radiofrequency antennas operation, core W, Ni content, Be source and the radiated power are higher for π/2 in comparison to dipole antenna phasing. Lowest core Ni, W content and radiated power is clearly observed for H plasmas in comparison to D and T, where for this ICRH scenario behaviour was similar. However, lower Be photon flux is observed for T in comparison to D plasmas. Be sputtering by He particles is responsible for such an effect. Additionally, several computer simulations were conducted using the COREDIV code. The difference in the electron temperature was due to the difference in the isotope masses. Increased temperature in the central plasma in the case of T plasmas leads to higher radiation in the central plasma in comparison to H plasmas. As a result, the power across separatrix is lower and the temperature on the divertor plate decreases with the increase of the isotope mass. At these temperatures on the divertor plate, W is not sputtered by the main plasma ions H, D and T and by He. For the N = 1 H ICRH scenario clear difference between D and T plasma was observed with higher metallic impurity content for T plasma in comparison to D. Impurity content in the plasmas is found to be sensitive to the power balance between the antenna straps. Its minimum is observed for the maximum of P cen/P tot.

Characterization of an RF-excited broad beam ion source operated with a mixture of CHF3 and O2

The composition and ion energy distributions of the main ion species of an ion beam were recorded and analyzed. The RF-type broad beam ion source was operated with a mixture of CHF3 and O2. A plasma bridge neutralizer operating with Ar was employed for ion beam neutralization. The data were collected with an energy-selective mass spectrometer (ESMS). The mass spectrum showed numerous ion species, beginning with ionized molecules, dissociation products of the process gases and products from reactions with background gas and the plasma discharge vessel, and the extraction system. For a quantification of the ion beam composition, the mass dependent transmission functions for two ESMS were determined. The ion energy distributions show that, in comparison to operation with inert gases, there are additional slower ions present. These ions can be related to dissociation processes outside of the ion beam source. As a result of their typically lower etching yield, these slower ions affect the etching behavior.

Characteristics of fine dust pollution PM₂.₅ in Hanoi in 2021

Fine particulate matter (PM2.5) is one of the most dangerous pollutions in the atmosphere in the Hanoi capital. PM2.5 fine dust pollution characteristics in Hanoi in the duration from 5/2021 to 3/2022 have been studied. The concentration of main chemical elements (such as As, Br, Ca, Cd, Ce, Cl, Cu, Fe, K, Mn, Pb, S, Sr, Ti, Zn, Zr…), main water-soluble ions (such as Na+, NH4+, K+, Mg2+, Ca2+, SO42-, Cl-, NO3-, F-, NO2-) and black carbon (BC) in the PM2.5 sample have been analyzed. The average PM2.5 fine dust concentration was (78.09 ± 51.71) µg/m3 and ranged from 17.55 to 271.39 µg/m3. PM2.5 tends to increase and is about 3.12 times larger than Who Air Quality Guidelines 2005 (25 µg/m3 for PM2.5 24h). The average PM2.5 concentration in the rainy season from 5/2021 to 9/2021 was (51.97 ± 16.40) µg/m3. This value for the dry season from 10/2021 to 3/2022 was (104.70 ± 61.19) µg/m3. It is much higher than that in the rainy season about 2.01 times. The major contributors were the secondary components such as NH4+, SO42-, NO3- and BC... The main pollution contribution sources and the potential pollution areas map have been identified. This research shows a worrying picture of fine dust PM2.5 in Hanoi in the studying duration.

Density pedestal prediction model for tokamak plasmas

A model for the pedestal density prediction based on neutral penetration combined with pedestal transport is presented. The model is tested against a pedestal database of JET-ILW Type I ELMy H-modes showing good agreement over a wide range of parameters both in standalone modelling (using the experimental temperature profile) and in full Europed modelling that predicts both density and temperature pedestals simultaneously. The model is further tested for ASDEX Upgrade and MAST-U Type I ELMy H-modes and both are found to agree with the same model parameters as for JET-ILW. The JET-ILW experiment where the isotope of the main ion is varied in a D/T scan at constant gas rate and constant βN is successfully modelled as long as the separatrix density ( ne,sep) and pedestal transport coefficient ratio ( D/χ) are varied in accordance with the experimentally observed variation of ne,sep and the isotope dependence of D/χ found in gyrokinetic simulations. The predictions are found to be sensitive to ne,sep which is why the model is combined with an ne,sep model to predict the pedestal for the STEP fusion reactor.

Efficient Nimesulide degradation via chlorination and sun-simulated radiation: Kinetic insights, reactive species formation, and application to real wastewater

Hypochlorite mediated oxidation had been established as an efficient process for degrading organic pollutants in water. In this research work, it was evaluated the synergistic potential of solar light irradiation combined with hypochlorite on a emerging contaminant model such as Nimesulide (NIM), a nonsteroidal anti-inflammatory drug. These experiments shown that at pH 3.0, where only hypochlorous acid (HOCl) prevails, the degradation constant of NIM exhibited an increase from 2.50 × 10−4 s−1 (under dark conditions) to 1.53 × 10−3 s−1 (sun-simulated radiation), signifying an approximately six-fold acceleration in degradation. Moreover, under approximately neutral pH value (7.5) wherein both HOCl and hypochlorite ion (ClO−) coexist, the enhancement observed was approximately twofold, in particular a mineralization up to 32 % was observed. This investigation also included quenching experiments conducted at varying pH levels, shedding light on the role of specific reactive species and their contributions to the degradation mechanism. The impact of synergistic effect between solar-simulated irradiation and hypochlorite systems on NIM degradation showcases a remarkable kinetic enhancement, particularly evident at lower pH values. The degradation byproducts have been identified via high resolution HPLC-MS and the main ion formed during the reaction have been monitored by IC-MS. Experiments in real sewage treatment plant waters using sun radiation revealed the promising potential and efficiency of this alternative method, despite a comparatively lower degradation rates when compared with UV lamp application. This approach offers a sustainable and economically advantageous solution for wastewater treatment.

Simulation studies of tungsten impurity behaviors in helium plasma in comparison with deuterium plasma via SOLPS-ITER

The sputtering and transport of tungsten (W) impurities in helium (He) and deuterium (D) plasma discharges are compared using the SOLPS-ITER code. To reduce the computational resources of modeling, W ions are treated using the bundled charge state model. The results show that the W erosion flux of He plasma is almost a factor of two higher than that of D plasma under the same upstream electron density and heating power due to the higher W sputtering yield in He plasma. Moreover, the W self-sputtering flux is significantly higher than the W flux sputtered by the main ions. The leakage and retention of W impurities in the divertor region is also analyzed. W ions mainly escape from the near scrape-off layer (SOL) region through the divertor entrance as the stagnation point of the average W impurity poloidal velocity is considerably closer to the target plates in the near SOL region. Furthermore, the leakage flux of W ions in He plasma is higher than that in D plasma, mainly because of the higher W sputtering level in He plasma, which results in a larger W density. W ions with low-lying charge states, mostly comprising the charge state of W10–12+, easily escape from the divertor through the near SOL flux tubes in both D and He plasmas. In addition, the effects of upstream electron density on W sputtering and retention in He and D plasma discharges are presented.

Dynamic characteristics and evolution laws of underground brine in Mahai salt lake of Qaidam Basin during mining process

In the late stage of underground brine mining in salt lakes, the method of injecting fresh water is often used to extract the salt from the brine storage medium. This method of freshwater displacement breaks the original water–rock equilibrium and changes the evolution process of the original underground brine. To explore the mechanism of salt release in saline water-bearing media under conditions of relatively fresh lake water dissolution, this paper analyzes the changes in the chemical parameters of brine from 168 sampling points in the Mahai salt lake in the Qaidam Basin at three stages (before exploitation, during exploitation, and late exploitation) by correlation analysis, ion ratio analysis, and other methods and investigate the variations in porosity and the evolution laws of brine. The results show that the changes in the main ion content and brine mineralization during the exploitation process are small. The changes in Ca2+ content are significant due to the low solubility of calcium minerals, the precipitation of gypsum during the mixing process, and the adsorption of cations by alternating with Ca2+. Primary intergranular pore skeletons are easily corroded to form secondary pores, which increase the geological porosity. Na+ and Cl- are the dominant ions in the brine in the study area, but the concentration of Ca2 + decreased significantly under the influence of mining, by 41.7% in the middle period and 24.5% in the late period. The correlation between Ca2+ and salinity changes significantly in different mining stages, and the reason for the decrease of Ca2+ may be due to the influence of mineral dissolution, mixing, and anion-cation exchange. The porosity of the layer in the study area showed the opposite trend of Ca2+, and the porosity increased first and then decreased. The innovation of this paper lies in analyzing the reasons and mechanisms of the disturbance of artificial dissolution mining on stratum structure by comparing the hydrochemical characteristics and porosity of underground brine storage media in three different mining stages. The research in this paper provides a theoretical basis for the calculation of brine resource reserves and the sustainable development of underground brine in salt lake areas.

Investigation of fast ion effects on core turbulence in FIRE mode plasmas

Further investigation of fast ion effects on turbulence and transport in the fast ion regulated enhancement (FIRE) mode discharge (Han et al 2022 Nature 609 269–275) was performed in this work as a continuation of a previous study (Kim et al 2023 Nucl. Fusion 63 124001) that showed that the dominant turbulence suppression mechanism by fast ions is the dilution effect in the FIRE mode discharge. The current study includes (i) the impact of the fast ion relevant mode observed in the simulation of thermal energy flux, (ii) dilution effects by fast ions compared to dilution effects by other species, and (iii) fast ion effects on electron-scale turbulence. First, nonlinear gyrokinetic simulation results show that turbulence is significantly suppressed even without the fast ion relevant mode, indicating that the impact of this mode on thermal transport is not significant in this discharge. Second, further analysis on the dilution effects shows the three following results: Turbulence is not completely suppressed by the reduced main ion density fraction effect due to impurities; the reduction in energy flux can be limited by a certain impurity mode that is destabilized by a high impurity density gradient from adjusting the main ion density gradient; electrons can contribute to turbulence suppression through the main ion density gradient change, although this effect is less significant compared to other species. Third, we observe that two fast ion effects can influence the linear growth rate of the electron-scale turbulence mode. The growth rate decreases by an increase in β∗(≡(−8π/B2)dp/dr) and increases by dilution effects, suggesting that fast ion effects on electron-scale turbulence can differ depending on the operation scenario, such as the fast ion fraction. The comprehensive analysis performed in this study can enhance our understanding of fast ion physics, required for burning plasma operation in the future.

Groundwater Chemical Trends Analyses in the Piedmont Po Plain (NW Italy): Comparison with Groundwater Level Variations (2000–2020)

The concentrations of chemicals in the groundwater chemical values in the Piedmont Po Plain (NW Italy) show significant temporal variability and need to be characterised due to the lack of regional-scale assessments. The aim of this study was to analyse the trends (period 2000–2020) in the main physicochemical parameters and main ions in 227 wells in the shallow aquifer and to identify the potential causes. The identification of change points (points of sudden change) and comparisons with groundwater level variations were also performed. Results highlight general increasing trends for Na, Cl and HCO3, decreasing trends for SO4 and NO3, stationary conditions for pH and heterogeneous behaviours for electrolytic conductivity, Ca and Mg. Change points occurred in at least 50% of the monitoring wells, mainly during the 2008–2011 period. The comparison between groundwater levels and chemistry highlights a direct proportionality. Superimposed processes that induce an absence of proportionality are shown. The comparison of results with those of previous studies conducted under similar conditions revealed similar variations.. In conclusion, the potential responsible factors (e.g., road-salt dissolution and agricultural practices) and the relevant role of groundwater level variation were identified.

СОВРЕМЕННАЯ ГИДРОХИМИЧЕСКАЯ ХАРАКТЕРИСТИКА ВОДНЫХ ОБЪЕКТОВ КАЗАХСТАНСКОЙ ЧАСТИ БАССЕЙНА Р. ЕРТИС

The article presents materials from our own research on the study of the distribution of the mineralization, ionic composition, hardness, dissolved gases and pH values in various components of the river ecosystem of the Kazakhstan part of the Ertis river basin in the summer of 2023. It has been established that the water of the Black Ertis river is ranked in terms of mineralization to ultra-fresh, the value of total hardness – to soft, the content and ratio of the main ions - to the carbonate class, calcium group, the second type. Within the Pavlodar region, the concentration of the main salt-forming ions in the water of the Ertis River increases on average by 1.7...2.4 times, the water becomes fresh, the Alekin water index remains CCaII throughout the entire flow. The mineralization of water in the floodplain lakes Orlovskoye, Staritsa, Kurkol differs little from the water of the river Irtysh. The value of all studied indicators in the water of the Ertis River, its tributaries and lakes does not exceed the maximum permissible concentration. The water of all studied water bodies, with the exception of the storage lake Balkyldak, in terms of the content of standardized main ions and mineralization, belongs to quality class 1, is suitable for all types of water use and corresponds to “very good” quality. The wastewater storage tank Balkyldak has water of high salinity (19.42 g/dm3), very hard, highly metamorphosed sodium chloride composition of the third type and it can be recommended for the extraction of bischofite, halite and gypsum.