Abundant Ions Research Articles

Three-Dimensional Graphene-Wrapped CoSe2 Nanowires for High-Performance Asymmetric Supercapacitors

Herein, a three-dimensional graphene (3DG)-coated porous nanowire architecture was developed, which exhibited favorable multiscale and multidimensional porous nanostructures, resulting in an airgel (3DG/CoSe2NWs) with abundant ion transport channels, high specific surface area, and excellent electrical conductivity. This airgel can be used directly as a flexible binder-free electrode with a high specific capacity of 1272 F g–1 at 1 A g–1 and an excellent rate capability of 1156 F g–1 when the current density was increased to 10 A g–1. The prepared asymmetric supercapacitor (3DG/CoSe2NWs//AC) exhibited excellent cycle stability with a coulombic efficiency of 96.19% at 5 A g–1 after 10,000 cycles. The performance of the flexible asymmetric supercapacitor (ASC) device under different bending angles was evaluated, and the discharge stability was confirmed, which indicated its potential in practical applications. Furthermore, two 3DG/CoSe2NWs//AC ASCs (1 cm × 3 cm) connected in series were able to light up an LED lamp, highlighting the promising prospect of the device.

Expert Algorithm for Substance Identification Using Mass Spectrometry: Statistical Foundations in Unimolecular Reaction Rate Theory.

This study aims to resolve one of the longest-standing problems in mass spectrometry, which is how to accurately identify an organic substance from its mass spectrum when a spectrum of the suspected substance has not been analyzed contemporaneously on the same instrument. Part one of this two-part report describes how Rice-Ramsperger-Kassel-Marcus (RRKM) theory predicts that many branching ratios in replicate electron-ionization mass spectra will provide approximately linear correlations when analysis conditions change within or between instruments. Here, proof-of-concept general linear modeling is based on the 20 most abundant fragments in a database of 128 training spectra of cocaine collected over 6 months in an operational crime laboratory. The statistical validity of the approach is confirmed through both analysis of variance (ANOVA) of the regression models and assessment of the distributions of the residuals of the models. General linear modeling models typically explain more than 90% of the variance in normalized abundances. When the linear models from the training set are applied to 175 additional known positive cocaine spectra from more than 20 different laboratories, the linear models enabled ion abundances to be predicted with an accuracy of <2% relative to the base peak, even though the measured abundances vary by more than 30%. The same models were also applied to 716 known negative spectra, including the diastereomers of cocaine: allococaine, pseudococaine, and pseudoallococaine, and the residual errors were larger for the known negatives than for known positives. The second part of the manuscript describes how general linear regression modeling can serve as the basis for binary classification and reliable identification of cocaine from its diastereomers and all other known negatives.

Expert Algorithm for Substance Identification Using Mass Spectrometry: Application to the Identification of Cocaine on Different Instruments Using Binary Classification Models.

This is the second of two manuscripts describing how general linear modeling (GLM) of a selection of the most abundant normalized fragment ion abundances of replicate mass spectra from one laboratory can be used in conjunction with binary classifiers to enable specific and selective identifications with reportable error rates of spectra from other laboratories. Here, the proof-of-concept uses a training set of 128 replicate cocaine spectra from one crime laboratory as the basis of GLM modeling. GLM models for the 20 most abundant fragments of cocaine were then applied to 175 additional test/validation cocaine spectra collected in more than a dozen crime laboratories and 716 known negative spectra, which included 10 spectra of three diastereomers of cocaine. Spectral similarity and dissimilarity between the measured and predicted abundances were assessed using a variety of conventional measures, including the mean absolute residual and NIST's spectral similarity score. For each spectral measure, GLM predictions were compared to the traditional exemplar approach, which used the average of the cocaine training set as the consensus spectrum for comparisons. In unsupervised models, EASI provided better than a 95% true positive rate for cocaine with a 0% false positive rate. A supervised binary logistic regression model provided 100% accuracy and no errors using EASI-predicted abundances of only four peaks at m/z 152, 198, 272, and 303. Regardless of the measure of spectral similarity, error rates for identifications using EASI were superior to the traditional exemplar/consensus approach. As a supervised binary classifier, EASI was more reliable than using Mahalanobis distances.

Density biases and temperature relations for DESIRED H ii regions

ABSTRACT We present a first study based on the analysis of the DEep Spectra of Ionized REgions Data base (DESIRED). This is a compilation of 190 high signal-to-noise ratio optical spectra of $\mathrm{H\, \scriptstyle II}$ regions and other photoionized nebulae, mostly observed with 8–10 m telescopes and containing ∼29 380 emission lines. We find that the electron density –ne– of the objects is underestimated when [$\mathrm{S\, \scriptstyle II}$] λ6731/λ6716 and/or [$\mathrm{O\, \scriptstyle II}$] λ3726/λ3729 are the only density indicators available. This is produced by the non-linear density dependence of the indicators in the presence of density inhomogeneities. The average underestimate is ∼300 cm−3 in extragalactic $\mathrm{H\, \scriptstyle II}$ regions, introducing systematic overestimates of Te([$\mathrm{O\, \scriptstyle II}$]) and Te([$\mathrm{S\, \scriptstyle II}$]) compared to Te([$\mathrm{N\, \scriptstyle II}$]). The high-sensitivity of [$\mathrm{O\, \scriptstyle II}$] λλ7319 + 20 + 30 + 31/λλ3726 + 29 and [$\mathrm{S\, \scriptstyle II}$] λλ4069 + 76/λλ6716 + 31 to density makes them more suitable for the diagnosis of the presence of high-density clumps. If Te([$\mathrm{N\, \scriptstyle II}$]) is adopted, the density underestimate has a small impact in the ionic abundances derived from optical spectra, being limited to up to ∼0.1 dex when auroral [$\mathrm{S\, \scriptstyle II}$] and/or [$\mathrm{O\, \scriptstyle II}$] lines are used. However, these density effects are critical for the analysis of infrared fine structure lines, such as those observed by the JWST in local star forming regions, implying strong underestimates of the ionic abundances. We present temperature relations between Te([$\mathrm{O\, \scriptstyle III}$]), Te([$\mathrm{Ar\, \scriptstyle III}$]), Te([$\mathrm{S\, \scriptstyle III}$]), and Te([$\mathrm{N\, \scriptstyle II}$]) for the extragalactic $\mathrm{H\, \scriptstyle II}$ regions. We confirm a non-linear dependence between Te([$\mathrm{O\, \scriptstyle III}$]) and Te([$\mathrm{N\, \scriptstyle II}$]) due to a more rapid increase of Te([$\mathrm{O\, \scriptstyle III}$]) at lower metallicities.

Electrical Resistivity Imaging for Identifying Critical Sulfate Concentration Zones Along Highways

Assessing sulfate concentration levels and their distributions within road alignments is crucial for the design of highway projects. Sulfate minerals in soils react with calcium-based additives, leading to sulfate-induced heaving and pavement failures. However, a reasonable assessment of the extent and levels of sulfate concentration using current practices, such as conventional laboratory-based methods, is still challenging because of the spatial heterogeneity of sulfate minerals and their seasonal fluctuations. This study aims to assess the application of electrical resistivity imaging (ERI) to determine levels and distributions of sulfate concentration. Finite element and least-squares optimization were used to process the data and generate subsurface inverted resistivity profiles. Fourteen ERI surveys were carried out for two sites with a potentially high risk of sulfate-induced heaving to help determine the extent of critical sulfate concentration zones. Laboratory tests (sulfate and moisture content tests) were conducted on ten samples collected from the field sites to validate ERI findings. The results showed that electrical resistivities of critical sulfate concentration zones are significantly lower than typical ranges of electrical resistivity of earth materials because of the abundance of salt ions in pore water, which facilitates the flow of electric current. The findings of this study were consistent with laboratory test results in determining the sulfate concentration levels. This study showed that ERI successfully provides a rapid and continuous assessment of critical sulfate concentration zones within highway alignments. The findings of this study will help materials and pavement engineers determine where alternative materials and pavement designs are needed.

Rapid imaging of unsaturated lipids at isomer level using photoepoxidation

Unsaturated lipids play an essential role in living organisms, and their different isomers show significant functional differences. Therefore, in situ characterization of unsaturated lipids in tissues needs to be extended to isomer level. However, the exposure of tissue sections to an open environment for a long time may cause cell autolysis or corruption, and current unsaturated lipid imaging methods still face challenges in efficiency. This paper proposes an imaging method based on photoepoxidation coupled with air-flow-assisted desorption electrospray ionization mass spectrometry (AFADESI-MS) to rapidly realize the spatial characterization of unsaturated lipids at the isomer level. The technique has a fast response speed, high epoxide yield (>80%), and high diagnostic ion abundance. After 0.5 min of photoepoxidation, the derivation product yield ratio reached 24.6%. This method rapidly identified six glycerophospholipid isomers containing an 18:1 acyl chain in normal rat liver tissue. Then the imaging method was applied in nude mice lung cancer tissue and human thyroid cancer tissue, with only 3 min photoepoxidation. Results successfully characterized the location and range of unsaturated lipid isomers and revealed their enrichment in tumor tissue. In addition, the experiment shows that the variational trend of the ratio of unsaturated lipid isomers in different types of tumor samples is different. Based on the advantages of efficiency and convenience, this method is prospective for screening unsaturated lipid markers and pathological research of related diseases.

Fe3O4 Nanoparticle/Graphene Oxide Composites as Selective Probes and Self-Matrixes for Pesticide Detection by Electrochemistry and Laser Desorption/Ionization Mass Spectrometry

An Fe3O4 nanoparticle/graphene oxide (GO) magnetic nanocomposite is synthesized and first applied as a selective probe for simultaneous detection of carbofuran (CBF) and carbendazim (CBZ) by electrochemistry and LDI-MS with MS imaging in real fruit samples. The high binding energies of the Fe3O4 nanoparticle/GO magnetic nanocomposite with target pesticides are verified by density functional theory. The Fe3O4/GO nanocomposite-modified electrode enhances the electrocatalytic property of the pesticides and provides a linear range of 1–250 μM with LODs of 0.06 and 0.18 μM for CBF and CBZ, respectively. For LDI-MS, after magnetic separation, CBF and CBZ bound to the magnetic nanocomposite are readily ionized by using Fe3O4/GO as a self-matrix, leading to high ion abundance with a linear range of 0.25–1000 μM and LODs of 0.25 μM for both pesticides. Furthermore, CBF and CBZ bound to Fe3O4/GO spiked in pear are visualized by imaging MS, illustrating the distribution of these pesticides in real pear peels. LOD values obtained from both detection techniques are lower than the maximum residue level (MRL) in the database of these pesticide residues, suggesting that this platform might be an alternative tool for the selective detection of pesticide residues in fruit samples.

Synthesis of co-pyrolyzed biochar using red mud and peanut shell for removing phosphate from pickling wastewater: Performance and mechanism

Iron (Fe)/iron oxide-modified biochar has practicable adsorption capability for phosphorus (P), but it is expensive. In this study, we synthesized novel low-cost and eco-friendly adsorbents co-pyrolyzed biochars using Fe-rich red mud (RM) and peanut shell (PS) wastes via a one-step pyrolysis process for removing P from pickling wastewater. The preparation conditions (heating rate, pyrolysis temperature, and feedstock ratio) and P adsorption behaviors were systematically investigated. In addition, a series of characterization and approximate site energy distribution (ASED) analyses were conducted to understand the P adsorption mechanisms. The magnetic biochar (BR7P3) with m (RM):m (PS) of 7:3 prepared at 900°C and 10 °C/min had a high surface area (164.43 m2/g) and different abundant ions (including Fe3+, and Al3+). In addition, BR7P3 exhibited the best P removal capability (142.6 mg/g). The Fe2O3 from RM was successfully reduced to Fe0, which was easily oxidized as Fe3+ to precipitate with H2PO4−. The electrostatic effect, Fe–O–P bonding, and surface precipitation were the main mechanisms of P removal. ASED analyses revealed that high distribution frequency and solution temperature led to a high P adsorption rate of the adsorbent. Therefore, this study provides new insight into the waste-to-wealth strategy by transforming PS and RM into mineral-biomass biochar with excellent P adsorption capability and environmental adaptability.

Dynamical Response of Solar Wind Charge Exchange Soft X-Ray Emission in Earth’s Magnetosphere to the Solar Wind Proton Flux

This work studies the dynamic response of solar wind charge exchange (SWCX) soft X-ray emission in the Earth’s magnetosphere to the solar wind proton flux. Unlike previous studies that attempted to use complex magnetohydrodynamic models to match the details of observed SWCX of a necessarily limited number of cases, this work focuses on determining the changes over individual observations in a much larger sample. To provide the cleanest test, we selected XMM-Newton observations when the solar wind proton flux changed suddenly by a factor greater than 1.5 and calculated the correlation coefficient between the SWCX emission in the 0.5–0.7 keV band and the proton flux. We find that the dynamical response is weak when the solar wind proton flux is low (<10,000 n*km/cc/s) because its variation is smaller than the uncertainty due to other emission components, but this response increases with the proton flux and its change value. The response is improved when the valence state of solar wind ions is high, as a higher abundance of ions generating SWCX can produce a greater correlation even though the proton flux is relatively low. It is conducive to the study of interplanetary coronal mass ejections (ICMEs) because ions in ICMEs are usually highly ionized. For XMM-Newton, the 0.5–0.7 keV band shows the strongest correlation, as the instrumental response decreases at lower energies and the SWCX emission decreases at higher energies. Moreover, the closer the satellite line of sight is to the subsolar magnetopause with the strongest SWCX emissivity, the better the correlation.

Novel porous CoS1.097@carbon nanofibers as flexible and binder-free anode material for sodium-ion batteries

Transition metal sulfides (TMSs) have received numerous attention as anode materials for sodium-ion batteries because of the high theoretical capacity. So far, the Na-storage performance of TMSs is still unsatisfactory due to the structural degeneration that induced by the volume change upon redox process. Herein, a novel flexible and binder-free anode material of porous CoS1.097@carbon nanofibers was facilely constructed by means of the electrospinning, carbonization and sulfidation processes. The porous CoS1.097@carbon nanofibers display unique structure with CoS1.097 nanoparticles confined into porous N-doped carbon nanofibers, and can provide sufficient active sites, high electrical conductivity, reduced ion diffusion distance, abundant ion migration pathways, desirable voids for alleviating the volume variation, and rigid structural stability for efficient Na-storage. In consequence, the flexible and binder-free electrode material delivers high initial discharge capacity, enhanced rate capability and long-term cycling life. Besides, intrinsic diffusion and electrochemical storage behavior of Na+ ions were emphatically disclosed. This work paves a facile route for the synthesis of flexible and binder-free TMSs-based anode materials, promoting the practical application of wearable sodium-ion batteries.

Highly selective chromogenic and fluorogenic probe based on benzothiazole‐thiosemicarbazone Schiff base for detection of copper (II) in real samples

AbstractCopper is the third most abundant essential transition metal ion in the human body. It's responsible for important activities in many living things, but excessive intake of Cu2+ can lead to a range of diseases. A colorimetric and turn‐off fluorescent probe (E)‐2‐(5‐(benzothiazol‐2‐yl)‐2‐(diethylamino)‐4‐hydroxybenzylidene)‐N‐phenylhydrazine‐1‐carbothioamide (ZTR) was designed and synthesized by thiosemicarbazone Schiff base as a specific complexes site strategy to achieve highly specific Cu2+ detection. The fluorescence of the probe ZTR solution fell dramatically when Cu2+ was added, and its appearance changed from dazzling blue to nearly colorless. The simple structure and readily available fluorescent probe provide a novel approach for the quantitative detection of Cu2+ in the linear range from 0 to 0.12 μM, with a detection limit down to 16 nM, and with high selectivity for Cu2+ over 15 other metal ions. Job’s plot analysis showed that probe ZTR and Cu2+ formed a 1:1 coordination complex. In addition, because of its low detection limits and fast response time, the created fluorescent molecule was effectively used to study the target ions on test paper strips and in water samples.))

Detection of some synthetic cannabinoids using GC-PCI-MS/MS: Comparison between isobutane and ammonia as reagent gases

This study was conducted to investigate the ionization and fragmentation behavior of some synthetic cannabinoids (SCs) by examining the formation of their product ions using reagent gases having different proton affinities. Ammonia (NH3) and isobutane (i-C4H10) were employed as reagent gases in positive chemical ionization (PCI) mode using gas chromatography-tandem mass spectrometry (GC-PCI-MS/MS) to qualitatively detect SCs. Under usual operational conditions, the intensity of responses in terms of either ion abundances or peak areas obtained for protonated molecules is significantly influenced by the reagent gases. Ammonia produced two to three times greater responses than isobutane. Additionally, the results showed that the NH3–CI and i-C4H10–CI spectra do not contain the adduct ions for these SCs.

A multifunctional Eu2-cluster coordination polymer as a luminescent probe of imidacloprid and renewable catalyst for the fixation of CO2 with epoxides

A bifunctional coordination polymer material is of great significance for the environmentally friendly applications due to its inherent advantages such as abundant active sites and characteristic metal ions. Here, a 3D Eu2-based framework 1 ({[Eu2(BTB)2(H2O)2]}n, H3BTB = 1,3,5-tris(4-carboxyphenyl)benzene) has been prepared through solvothermal method, presenting excellent chemical stability and thermal stability. Importantly, compound 1 serving as a recyclable luminescence probe (five times) can recognize pesticide imidacloprid with detection limit of 4.9 ppm, featuring good selectivity and anti-interference performance in simulative serum and urine environments. Additionally, in view of abundant Lewis-acid sites, compound 1 can be employed as an efficient catalyst for the conversion reaction of CO2 and epoxides with different substituent groups into high-valued chemical substances (five-cycled carbonate) without solvent. More importantly, this heterogeneous catalyst can be reused without significant change in catalytic activity after five reaction cycles, which are further confirmed by the PXRD, ICP and IR analyses of catalyst 1 after the fifth recycling. This work greatly enriched the applications of multifunctional coordination materials in CO2 cycloaddition catalysis and luminescence sensing.

Field surveys reveal physicochemical conditions promoting occurrence and high abundance of an invasive freshwater snail (Potamopyrgus antipodarum)

Environmental conditions promoting the occurrence and high abundance of non-native taxa are linked to critical stages of species invasions: establishment, whether a site can sustain a population of the non-native taxon, and impact, the extent to which the consequences of establishment negatively affect the invaded ecosystem. Using surveys across environmental gradients, we examined the physicochemical conditions associated with the occurrence and abundance of the invasive New Zealand mudsnail (Potamopyrgus antipodarum) and co-occurring native mollusks. Abundance of Potamopyrgus very strongly increased with stream width and conductivity (specifically with chloride, sulfate, potassium, and sodium ions). Also, Potamopyrgus were most likely to occur at sites with relatively low pH and water velocity and relatively high calcium ion concentration and abundance also slightly increased in these conditions. The physicochemical conditions indicate the characteristics of sites that are suitable for establishment and secondary spread of Potamopyrgus. Native mollusks differed from Potamopyrgus in the physicochemical conditions associated with abundance suggesting that variation among habitats could permit native mollusks to persist at larger geographic scales even if they often co-occur with Potamopyrgus. Abundance of native Physa moderately decreased with abundance of Potamopyrgus. Because abundance of Physa and Potamopyrgus responded oppositely to stream width and conductivity, the negative relationship between the abundance of these two taxa may be caused by contrasting responses to physicochemical conditions, acting alone or in concert with biotic interactions.

One-Step High-Temperature Electrodeposition of Fe-Based Films as Efficient Water Oxidation Catalysts

Electrolysis of water to produce hydrogen requires an efficient catalyst preferably made of cheap and abundant metal ions for the improved water oxidation reaction. An Fe-based film has been deposited in a single step by electrochemical deposition at temperatures higher than the room temperature. Until now, the electrodeposition of iron oxide has been carried out at 298 K or at lower temperatures under a controlled atmosphere to prohibit atmospheric oxidation of Fe2+ of the iron precursor. A metal inorganic complex, ferrocene, and non-aqueous electrolyte medium propylene carbonate have been used to achieve electrodeposition of iron oxide without the need of any inert or controlled atmosphere. At 298 K, the amorphous film was formed, whereas at 313 K and at higher temperatures, the hematite film was grown, as confirmed by X-ray diffraction. The transformation of iron of the ferrocene into a higher oxidation state under the experimental conditions used was further confirmed by X-ray photoelectron spectroscopy, ultraviolet-visible, and electron paramagnetic resonance spectroscopic methods. The films deposited at 313 K showed the best performance for water oxidation with remarkable long-term electrocatalytic stability and an impressive turnover frequency of 0.028 s-1 which was 4.5 times higher than that of films deposited at 298 K (0.006 s-1). The observed overpotential to achieve a current density of 10 mA cm-2 was found to be 100 mV less for the film deposited at 313 K compared to room-temperature-derived films under similar experimental conditions. Furthermore, electrochemical impedance data revealed that films obtained at 313 K have the least charge transfer resistance (114 Ω) among all, supporting the most efficient electron transport in the film. To the best of our knowledge, this is the first-ever report where the crystalline iron-based film has been shown to be electrodeposited without any post-deposition additional treatment for alkaline oxygen evolution reaction application.

Comparison of rainwater quality before and during the MCO using chemometric analyses.

This study aimed to classify the spatiotemporal analysis of rainwater quality before and during the Movement Control Order (MCO) implementation due to the COVID-19 pandemic. Chemometric analysis was carried out on rainwater samples collected from 24-gauge stations throughout Malaysia to determine the samples' chemical content, pH, and conductivity. Other than that, hierarchical agglomerative cluster analysis (HACA) and discriminant analysis (DA) were used to classify the quality of rainwater at each location into four clusters, namely good, satisfactory, moderate, and bad clusters. Note that DA was carried out on the predefined clusters. The reduction in acidity levels occurred in 11 stations (46% of overall stations) after the MCO was implemented. Chemical content and ion abundance followed a downward trend, indicating that Cl- and Na+ were the most dominant among the anions and cations. Apart from that, NH4+, Ca2+, NO3-, and SO42- concentrations were evident in areas with significant anthropogenic activity, as there was a difference in the total chemical content in rainwater when compared before and during the MCO. Based on the dataset before the MCO, 75% of gauge stations were in the good cluster, 8.3% in the satisfactory cluster, 12.5% in the moderate cluster, and 4.2% in the bad cluster. Meanwhile, the dataset during the MCO shows that 72.7% of gauge stations were in the good cluster, 9.1% in the satisfactory cluster, 9.1% in the moderate, and 4.5% in the bad cluster. From this study, the chemometric analysis of the year 2020 rainwater chemical composite dataset strongly indicates that reduction of human activities during MCO affected the quality of rainwater.

A novel strategy for high energy density supercapacitors: Formation of cyanuric acid between Ti3C2Tx (MXene) interlayer hybrid electrodes

Ti3C2Tx (MXene) are attractive for electrode materials because of their high electrical conductivity, abundant interlayer ions and low density. However, the low energy density hinders its commercial application. Herein, a novel N-doped Ti3C2Tx MXene is synthesized by introducing a small organic molecule dicyandiamide (DCD) to tune the complex terminals. DCD can be inserted into the layers of Ti3C2Tx nanosheets while forming melamine by catalyst-free trimerization reaction. Then, melamine is converted into gt-C3N4 through high-temperature sintering. Finally, gt-C3N4 is oxidized to cyanuric acid (CA) through simple hydrothermal reaction. The prepared Ti3C2Tx/CA composite electrode exhibits up to 4.8 at.% nitrogen doping and has a stable triazine ring structure. It is also shown that the Ti3C2Tx/CA composite electrode has high specific capacitance and excellent cycling stability. More notably, it achieves an energy density of 51.1 Wh kg−1 at a power density of 2000 W kg−1, which exceeds the energy density of MXene based electrodes reported in the current literature. This excellent performance is attributed to the unique hydroxyl structure of the CA terminal and the excellent symmetry of CA in the composite electrode. In aqueous electrolytes, CA can form short chains during charging and the formation of short chains enables the storage of electrons and further provides a large number of new pseudocapacitive reaction sites for MXene. At the same time, the high electronegativity of the N and O atoms in CA also increases the electric double layer capacitor of the composite electrode to a certain extent, thus resulting in a high energy density of the composite electrode.

Integration of Geochemical Modeling, Multivariate Analysis, and Irrigation Indices for Assessing Groundwater Quality in the Al-Jawf Basin, Yemen

Water quality monitoring is crucial in managing water resources and ensuring their safety for human use and environmental health. In the Al-Jawf Basin, we conducted a study on the Quaternary aquifer, where various techniques were utilized to evaluate, simulate, and predict the groundwater quality (GWQ) for irrigation. These techniques include water quality indices (IWQIs), geochemical modeling, multivariate statistical analysis, geographic information systems (GIS), and adaptive neuro-fuzzy inference systems (ANFIS). Physicochemical analysis was conducted on the collected groundwater samples to determine their composition. The results showed that the order of abundance of ions was Ca2+ &gt; Mg2+ &gt; Na+ &gt; K+ and SO42− &gt; Cl− &gt; HCO3− &gt; NO3−. The assessment of groundwater quality for irrigation based on indices such as Irrigation water quality index (IWQI), sodium adsorption ratio(SAR), sodium percent (Na%), soluble sodium percentage (SSP), potential salinity (PS), and residual sodium carbonate RSC, which revealed moderate-to-severe restrictions in some samples. The Adaptive Neuro-Fuzzy Inference System (ANFIS) model was then used to predict the IWQIs with high accuracy during both the training and testing phases. Overall, these findings provide valuable information for decision-makers in water quality management and can aid in the sustainable development of water resources.

Rational design of ultrafine FeSe2 nanocrystals embedded within hollow mesoporous carbon bowls for potassium-ion batteries with long-term cycling stability and high volumetric capacity

• Bowl-like carbon/FeSe 2 composites are successfully synthesized by a facile method • Ultrafine FeSe 2 nanocrystals are well embedded in bowl-like carbon matrix • Bowl structure has a higher packing density than the conventional hollow structure • Compared with hollow structure, the volumetric capacity of sample increased by 60% • The KIB full cell composed of FeSe 2 @HMCB//PB has been demonstrated Hollow structures are commonly used to alleviate the mechanical stress on electrode materials and to provide more active sites in potassium-ion batteries (KIBs). Nevertheless, the excessive internal voids within these structures significantly reduce the packing density of particles, resulting in a relatively low volumetric energy density of the fabricated electrodes, which is undesirable for practical use. We designed a hollow mesoporous carbon bowl embedded with ultrafine bis(selanylidene)iron (FeSe 2 ) nanocrystals (FeSe 2 @HMCB) via a controllable impregnation method and subsequent selenization process for high-performance KIBs. The as-obtained FeSe 2 @HMCB can inherit the advantages of conventional hollow carbon-based composites, such as alleviation of volume variation in active materials, abundant ion storage sites, and high electrical conductivity. Simultaneously, the bowl structure has a higher packing density than the conventional hollow structure, resulting in a significant increase in the volumetric energy density of the fabricated electrodes. Because of these advantages, the FeSe 2 @HMCB exhibits a high, stable reversible capacity of 326 mA h g −1 even after 1,000 cycles at 0.5 A g −1 , and excellent rate capacities (182 mA h g −1 at 3.0 A g −1 ). Compared with the hollow structured counterpart, the volumetric capacity (mA h cm −3 ) of FeSe 2 @HMCB increased by 60%. Furthermore, a full cell consisting of FeSe 2 @HMCB//Prussian blue (PB) exhibits excellent electrochemical performance (99 mA h g −1 after 100 cycles at 0.1 A g −1 ).

Simple and precise method for determining relative amount of Fe3+ in Fe-gluconate

Reported is a simple and precise method for determining the relative amount of Fe3+ in a Fe-gluconate. The method is based on a linear relationship between the average isomer shift (spectrum's center of gravity) and the percentage content of the Fe3+ as found from Mössbauer spectra recorded on several samples of the Fe-gluconate and Ascofer® medicament. The new method has been tested by comparison the values of the relative abundance of the ferric ions obtained by a traditional way of the Mösbauer spectra analysis with those determined with the new method. The latter can be conveniently used in a pharmaceutical industry producing Fe-gluconate based medicaments for treating patients with iron deficiency anemia.