Search

[Display omitted] • GQD-DDT and GQD-MPA was synthesized using novel hydrothermal protocol. • GQD-DDT and GQD-MPA was used for the identification of cations using colorimetric and spectrophotometric assay. • GQD-DDT and GQD-MPA have well activity for ion sensing in aqueous solution. This study describes the synthesis of various types of thiolated-graphene quantum dots (GQDs) for the simultaneous multi-sensing of heavy metal ions using one-droplet microfluidic paper-based analytical devices (OD- µ PADs). For the first time, functionalized GQDs were synthesized and stabilized on the surface of hydrophobic fiber-glass with simple manufacturing and assembly strategy towards colorimetric chemosensing of ions including iron, copper, cobalt, mercury, chrome, manganese, and nickel. For this purpose, GQDs are functionalized by various organic species including cysteamine, decanethiol, and mercaptopropionic acid (MPA) towards specific electrostatic interaction with metal ions of Fe (II), Cu (II), Co(II), Hg (II), Mn (II), and Ni (II). Therefore, an innovative GQDs-based miniaturized chemo-system was proposed for the environmental analysis. Additionally, the results were confirmed using fluorescence spectrometry as an optical detection method. Finally, this simple and efficient colorimetric platform was used for facile metal ions detection in human urine models, and environmental fluids, which can provide a commercial device for sensing contaminants by non-professional users in biomedical/environmental mixture. As an economical technique, this platform presents a "mix-and-sense" system without dye (as a side substance) or chemical treatments. The low instrumental requirements, the color uniformity, and the disposability of OD- μ PADs approve the commercial application of the engineered ion-chemosensor. [ABSTRACT FROM AUTHOR]

Studying the adsorption behavior of cationic surfactants can help to develop more effective strategies to limit their dispersion in the environment. However, there have few studies on the adsorption of cationic surfactants from the perspective of critical micelle concentration (CMC). In this study, with cetyltrimethylammonium bromide (CTAB) and octadecyl trimethylammonium bromide (OTAB) serving as the model cationic surfactants, the effect of CMC on the adsorption behavior of cationic surfactant onto the surface of sodium alginate/silica (SA/SiO 2 ) microspheres was systematically revealed. The adsorption mechanism relative to CMC was investigated under different conditions, including surfactant concentration, pH, temperature, and adsorption time. The results suggest that at identical concentrations, the smaller the CMC value of the cationic surfactants, the greater the adsorption amount (q t ). q t for CTAB and OTAB were 583.2 and 678.0 mg/g respectively, with the concentration higher than their CMC value. When the concentration was lower than the CMC value of the cationic surfactants, q t for CTAB and OTAB were 123.2 and 138.7 mg/g, respectively. The CMC value of CTAB was lower than that of OTAB under identical conditions, suggesting that the adsorption of cationic surfactants is related to their CMC. These results are beneficial for the removal of cationic surfactants by adsorption methods., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Developing the delivery systems with high therapeutic efficacy and low side effects is of great interest and significance for anticancer therapy. Compared to the high cost in synthesizing new chemotherapeutic drugs, exploring the anticancer potentials of existing chemicals is more convenient and efficient. Sodium bicarbonate (BC), a simple inorganic salt, has shown its tumor inhibition capacity via regulating the acidity of tumor microenvironment. However, the effects of intracytoplasmic BC on tumor growth and the potentials of BC to serve as an anticancer agent are still unknown. Herein, we developed a BC-loaded cationic liposome system (BC-CLP) to deliver BC into the cytosol of cancer cells. The in vitro studies showed that the BC-CLP containing 1% BC (w/v) had a size of 112.9 nm and a zeta potential of 19.1 mV, which reduced the viability of the model cancer cells (human oral squamous cell carcinoma HSC-3 cells) to 13.7%. In contrast, the neutral BC-LP caused less than 50% viability reduction. We further found that BC-CLP released BC directly into cytoplasm via membrane fusion pathway rather than endocytosis, leading to the remarkable increase of cytosolic pH, which may contribute to the anticancer effect of BC-CLP. Our findings indicate that BC-CLP is a potential system for high-efficiency cancer therapy without causing drug-related side effects or resistance., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Antiphase bursting related to the rhythmic motor behavior exhibits complex dynamics modulated by the inhibitory synaptic current (Isyn), especially in the presence of the hyperpolarization-activated cation current (Ih). In the present paper, the dynamics of antiphase bursting modulated by the Ih and Isyn is studied in three aspects with a theoretical model. Firstly, the Isyn and the slow Ih with strong strength are the identified to be the necessary conditions for the antiphase bursting. The dependence of the antiphase bursting on the two currents is different for low (escape mode) and high (release mode) threshold voltages (Vth) of the inhibitory synapse. Secondly, more detailed co-regulations of the two currents to induce opposite changes of the bursting period are obtained. For the escape mode, increase of the Ih induces elevated membrane potential of the silence inhibited by a strong Isyn and shortened silence duration to go beyond Vth, resulting in reduced bursting period. For the release mode, increase of the Ih induces elevated tough value of the former part of the burst modulated by a nearly zero Isyn and lengthen burst duration to fall below Vth, resulting in prolonged bursting period. Finally, the fast-slow dynamics of the antiphase bursting are acquired. Using one-and two-parameter bifurcations of the fast subsystem of a single neuron, the burst of the antiphase bursting is related to the stable limit cycle, and the silence modulated by a strong Isyn to the stable equilibrium to a certain extent. The Ih mainly modulates the dynamics within the burst and quiescent state. Furthermore, with the fast subsystem of the coupled neurons, the silence is associated with the unstable equilibrium point. The results present theoretical explanations to the changes in the bursting period and fast-slow dynamics of the antiphase bursting modulated by the Isyn and Ih, which is helpful for understanding the antiphase bursting and modulating rhythmic motor patterns. [ABSTRACT FROM AUTHOR]

β-lactoglobulin (BLG) is the major whey protein with negative charges at neutral pH in aqueous media. Thus, the interaction with mucins, the major polyanionic component of mucus, is very weak due to the electrostatic repulsion between them. The present study postulates that cationization of BLG molecules may reverse the interaction characteristics between BLG and mucin from repulsive to associative. To this end, cationic-modified BLGs were prepared by grafting positively charged ethylenediamine (EDA) moieties into the negatively charged carboxyl groups on the aspartic and glutamic acid residues and compared with non-modified BLG upon mixing with porcine gastric mucin (PGM). To characterize the structural and conformational features of PGM, non/cationized BLGs, and their mixtures, various spectroscopic approaches, including zeta potential, dynamic light scattering (DLS), and circular dichroism (CD) spectroscopy were employed. Importantly, we have taken surface adsorption with optical waveguide lightmode spectroscopy (OWLS), and tribological properties with pin-on-disk tribometry at the sliding interface as the key approaches to determine the interaction nature between them as mixing PGM with polycations can lead to synergistic lubrication at the nonpolar substrate in neutral aqueous media as a result of an electrostatic association. All the spectroscopic studies and a substantial improvement in lubricity collectively supported a tenacious and associative interaction between PGM and cationized BLGs, but not between PGM and non-modified BLG. This study demonstrates a unique and successful approach to intensify the interaction between BLG and mucins, which is meaningful for a broad range of disciplines, including food science, macromolecular interactions, and biolubrication etc., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Nucleic acid delivery by viral and non-viral methods has been a cornerstone for the contemporary gene therapy aimed at correcting the defective genes, replacing of the missing genes, or downregulating the expression of anomalous genes is highly desirable for the management of various diseases. Ostensibly, it becomes paramount for the delivery vectors to intersect the biological barriers for accessing their destined site within the cellular environment. However, the lipophilic nature of biological membranes and their potential to limit the entry of large sized, charged, hydrophilic molecules thus presenting a sizeable challenge for the cellular integration of negatively charged nucleic acids. Furthermore, the susceptibility of nucleic acids towards the degrading enzymes (nucleases) in the lysosomes present in cytoplasm is another matter of concern for their cellular and nuclear delivery. Hence, there is a pressing need for the identification and development of cationic delivery systems which encapsulate the cargo nucleic acids where the charge facilitates their cellular entry by evading the membrane barriers, and the encapsulation shields them from the enzymatic attack in cytoplasm. Cycloamylose bearing a closed loop conformation presents a robust candidature in this regard owing to its remarkable encapsulating tendency towards nucleic acids including siRNA, CpG DNA, and siRNA. The presence of numerous hydroxyl groups on the cycloamylose periphery provides sites for its chemical modification for the introduction of cationic groups, including spermine, (3-Chloro-2 hydroxypropyl) trimethylammonium chloride (Q188), and diethyl aminoethane (DEAE). The resulting cationic cycloamylose possesses a remarkable transfection efficiency and provides stability to cargo oligonucleotides against endonucleases, in addition to modulating the undesirable side effects such as unwanted immune stimulation. Cycloamylose is known to interact with the cell membranes where they release certain membrane components such as phospholipids and cholesterol thereby resulting in membrane destabilization and permeabilization. Furthermore, cycloamylose derivatives also serve as formulation excipients for improving the efficiency of other gene delivery systems. This review delves into the various vector and non-vector-based gene delivery systems, their advantages, and limitations, eventually leading to the identification of cycloamylose as an ideal candidate for nucleic acid delivery. The synthesis of cationic cycloamylose is briefly discussed in each section followed by its application for specific delivery/transfection of a particular nucleic acid., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The coexistence of metal cations is often accompanied by organic pollution and could affect the environmental fate of organics by mediating the formation of cation bridges. However, the environmental fate and risk of organics in cation co-existing environments are poorly understood due to the lack of accurate identification of cation bridge formation and stability. In this study, the sorption of sulfamethoxazole (SMX) on montmorillonite (MT) with the coexistence of three different valence metal cations (Na + , Ca 2+ , and Cr 3+ ) was investigated. Ca 2+ and Cr 3+ can significantly promote the sorption of SMX on MT for about 5∼10 times promotion, respectively, while Na + bridges displayed little effect on the sorption of SMX. The sorption binding energy of SMX with MT-Ca (-44.01 kcal/mol) and MT-Cr (-64.57 kcal/mol) bridges was significantly lower than that with MT-Na (-38.45 kcal/mol) and MT (-39.39 kcal/mol), indicating that the sorption affinity of SMX on Cr and Ca bridges was much stronger. The higher valence of the cations also resulted in a more stable adsorbed SMX with less desorption fluctuation. In addition, the relatively higher initial concentration of SMX and the valence of cations increased the bonding density of the cation bridges, thus promoting the apparent sorption of SMX on MT to a certain extent. This work reveals the formation and function of cation bridges in the sorption of SMX on MT. It lays a theoretical foundation for further understanding the environmental fate and risk of organics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The aging process of microplastics (MPs) could significantly change their physical and chemical characteristics and impact their migration behavior in soil. However, the complex effects of different cations and humic acids (HA) on the migration of aged MPs through saturated media are not clear. In this research, the migration and retention of pristine/aged PSMPs (polystyrene microplastics) under combined effects of cations (Na + , Ca 2+ ) (ionic strength = 10 mM) and HA (0, 5, 15 mg/L) were investigated and analyzed in conjunction with the two-site kinetic retention model and DLVO theory. The findings showed that the aging process accelerated PSMPs migration under all tested conditions. Aged PSMPs were less susceptible to Ca 2+ than pristine PSMPs. Under Ca 2+ conditions, pristine/aged PSMPs showed higher retention than under Na + conditions in the absence of HA. Furthermore, under Na + conditions, the migration of aged PSMPs significantly increased at higher concentrations of HA. However, under Ca 2+ conditions, the migration of aged PSMPs decreased significantly at higher concentrations of HA. In higher HA conditions, HA, Ca 2+ , and PSMPs interact to cause larger aggregations, resulting in the sedimentation of aged PSMPs. The DLVO calculations and two-site kinetic retention models' results showed the detention of PSMPs was irreversible under higher HA conditions (15 mg/L) with Ca 2+ , and aged PSMPs were more susceptible to clogging. These findings may help to understand the potential risk of migration behavior of PSMPs in the soil-groundwater environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

A series of laboratory experiments are conducted to simulate the acidification and subsequent recovery of a sand aquifer exploited by in situ recovery (ISR) mining. A sulfuric acid solution (pH 2) is first injected into a column packed with sand from the Zoovch Ovoo uranium roll front deposit (Mongolia). Solutions representative of local groundwater or enriched in cations (Na + , Mg 2+ ) are then circulated through the column to simulate the inflow of aquifer water. pH and major ion concentrations (Na + , Cl - , SO 4 2- , Ca 2+ , Mg 2+ ) measured at the column outlet reproduce the overall evolution of porewater chemistry observed in the field. The presence of minor quantities of swelling clay minerals (≈6 wt% smectite) is shown to exert an important influence on the behavior of inorganic cations, particularly H + ) measured at the column outlet reproduce the overall evolution of porewater chemistry observed in the field. The presence of minor quantities of swelling clay minerals (≈6 wt% smectite) is shown to exert an important influence on the behavior of inorganic cations, particularly H + , via ion-exchange reactions. Numerical models that consider ion-exchange on smectite as the sole solid-solution interaction are able to reproduce variations in pH and cation concentrations in the column experiments. This highlights the importance of clay minerals in controlling H + mobility and demonstrates that sand from the studied aquifer can be described to a first order as an ion-exchanger. The present study confirms the key role of clay minerals in controlling water chemistry in acidic environments through ion-exchange processes. In a context of managing the long-term environmental footprint of industrial and mining activities (ISR, acid mine drainage…), this work will bring insights for modeling choices and identification of key parameters to help operators to define their production and/or remediation strategies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

It is important to study the steel corrosion inhibition behavior in complex chloride salt environments. This paper uses the fact that calcined layered double hydroxides (CLDHs) have a certain memory effect, which means that it can reabsorb water and anions and partially restore the lamellar structure under certain conditions. This work investigated the influence of cation types on the steel corrosion inhibition behavior of CLDH in saturated calcium hydroxide solution using equilibrium isotherms of Cl− uptake, the electrochemical method, X-ray diffraction (XRD), Fourier-transform infrared (FTIR), and scanning electron microscopy (SEM) techniques. The results show that the corrosion inhibition of the CLDH is affected by the cation types in the following order: Ca2+>Mg2+>K+≈Na+·Na+ and K+ increase the pH of the solution and decrease the corrosion inhibition of CLDH. The addition of Mg2+ can promote the reconstruction of Mg-Al-Zn-Cl hydrotalcite. The addition of Ca2+ can promote the formation of new Ca-Al layered double hydroxide (Ca-Al-LDH) and improve the corrosion inhibition. [ABSTRACT FROM AUTHOR]

• The mechanism of organic electrode weakening self-discharge effect of dual-ion battery was explored. • The performance of metal-free dual-ion batteries in different ionic liquid electrolytes was investigated. • The method of reducing the dissolution of organic electrode in ionic liquid electrolyte was discussed. The strong self-discharge reaction is one of the key factors limiting the practical use of dual-ion batteries, which leads to low coulombic efficiency and discharge capacity loss. It is of great significance to effectively reduce the self-discharge effect through redox reactions between organic electrodes and electrolytes. Herein, a dual-ion battery study that uses 1,4,5,8-naphthalenetetracarboxylic dianhydride as the anode and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide as the electrolyte is conducted. Due to the introduction of organic materials, the storage mechanism of cations on the anode is changed, which weakens the self-discharge effect. The battery shows a low self-discharge rate of 6.12% h−1 and a high discharge capacity of 114 mAh g−1. The voltage declines by only 0.14 V after resting for 15 h due to the strong redox reaction between Pyr 14 + cations and the C O groups of NTCDA. Meanwhile, a double-layer filter paper system with small porosity is used to improve the cycle performance of the battery. [ABSTRACT FROM AUTHOR]

In the past 20 years, perovskite-related research has attracted wide attention. The related research into two-dimensional/quasi-two-dimensional perovskite has propelled the research of perovskite materials to a new height. To improve the properties of quasi-2D perovskite, improve the stability of materials, and achieve specific functions, using different types, volumes, and lengths of organic spacers is an essential method. In this paper, quasi-2D perovskites with EDA (ethylene diammonium), PDA (1,3-propanediammonium), and BDA (1,4-butanediammonium) (m = 2–4) as organic spacers were prepared, and the effects of different organic spacers on the 2D perovskite were investigated. The results show that the length of the organic spacer significantly impacts the perovskite's properties. A shorter organic spacer can effectively reduce the quantum confinement and dielectric confinement in perovskite. It should be noted that if the organic spacer is too short, the stability of the quasi-2D perovskite will be greatly reduced. [ABSTRACT FROM AUTHOR]

A superatom is a cluster of atoms that acts like a single atom. Two main groups of superatoms are superalkalis and superhalogens, which mimic the chemistry of alkali and halogen atoms, respectively. The ionization energies of superalkalis are smaller than those of alkalis (<3.89 eV for cesium atom), and the electron affinities of superhalogens are larger than that of halogens (>3.61 eV for chlorine atom). Exploring new superalkali/superhalogen aims to provide reliable data and predictions of the use of such compounds as redox agents in the reduction/oxidation of counterpart systems, as well as the role they can play more generally in materials science. The low ionization energies of superalkalis make them candidates for catalysts for CO2 conversion into renewable fuels and value-added chemicals. The large electron affinity of superhalogens makes them strong oxidizing agents for bonding and removing toxic molecules from the environment. By using the superatoms as building blocks of cluster-assembled materials, we can achieve the functional features of atom-based materials (like conductivity or catalytic potential) while having more flexibility to achieve higher performance. This feature paper covers the issues of designing such compounds and demonstrates how modifications of the superatoms (superhalogens and superalkalis) allow for the tuning of the electronic structure and might be used to create unique functional materials. The designed superatoms can form stable perovskites for solar cells, electrolytes for Li-ion batteries of electric vehicles, superatomic solids, and semiconducting materials. The designed superatoms and their redox potential evaluation could help experimentalists create new materials for use in fields such as energy storage and climate change. [ABSTRACT FROM AUTHOR]

In fair weather, the vertical atmospheric electric field is oriented downward (positive in the earth surface ordinate system) in the global atmospheric circuit. Some researchers have revealed the unique phenomenon whereby once an upward vertical atmospheric electric field is observed in fair weather, an earthquake (EQ) follows within 2–48 h regardless of the EQ magnitude. However, the mechanism has not been explained with a suitable physical model. In this paper, a physical model is presented considering four types of forces acting on charged particles in the air. It is demonstrated that the heavier positive ions and lighter negative ions are rapidly separated. Finally, a reversed fair weather electrostatic field is formed by the above charge separation process. The simulation results have instructive significance for future observations and hazard predictions and still need further research. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Kirkuk University for Agricultural Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Cairns-distributed electrons and positive ions in a plasma made up of a negative dust fluid are taken into account to examine the presence of arbitrary amplitude dust-acoustic solitons. It has previously been noted that nonthermal ions and thermal electrons generate both compressive and rarefactive solitons. In this paper, we noticed that nonthermal electrons together with nonthermal ions are responsible for producing the rarefactive solitons. It is found that the Sagdeev potential strongly depends on plasma parameters, such as nonthermal index α and Mach number, which, in turn, influence the Sagdeev potential and solitons significantly. We also found that the critical match number and height of soliton increase with the nonthermal parameter α. We further note that the Sagdeev potential as a function of potential φ becomes more negative and the amplitude of the soliton also enhances as the value of Mach number rises. It is concluded that the model presented here based on nonthermal ions and electrons in a negative dust fluid provides a worthy interpretation for electrostatic solitons observed in space plasmas. [ABSTRACT FROM AUTHOR]

The tip size of metal protrusions is an important factor affecting corona discharge, since it influences the electric filed, the ionization range and strength around the protrusion defect. Most existing studies on the influence of protrusion tip size on corona discharge are implemented by experimental methods. However, these studies are difficult to obtain the microphysical process of charged particles, which is related to the generation of current pulses and electromagnetic (EM) waves. In this paper, a hydrodynamic simulation model is proposed to study the effect of protrusion tip size on the microphysical process and current pulses of negative corona discharge. A mapping relationship between microscopic behaviors of charged particles and current pulses is established by this simulation method. Based on the comparison of microphysical quantities, the effect of defect tip size on the detailed parameters of current pulses is clearly explained. It shows that with the increase of tip size under a constant voltage, all the five parameters of current pluses increase. The rising time is related to the effective ionization coefficient, while the falling time is dependent on the velocities of positive and negative ions. The experiment and simulation results coincide in current waveforms and all five parameters. [ABSTRACT FROM AUTHOR]

Supercapacitors have many applications in new energy and other high-tech fields. The desolvation effect on ions affects the capacity size of supercapacitors, and there are few relevant studies published in this field at present. In this experiment, bilayer graphene (BG) with a layer spacing of 4–10 Å was used as a model of flat pores and was calculated with first-principles calculations, which can effectively simulate the adsorption behaviour of porous carbon. The reaction energies of ions, propylene carbonate, and ionic complexes in bilayer graphene with different layer spacings were calculated, and the desolvation behaviour of lithium salt cations (Li+), tetraethyl quaternary ammonium salt cations (TEA+), triethyl methyl quaternary ammonium salt cations (TEMA+), and bipyrrolidinium quaternary ammonium salt cations (SBP+) was investigated. The calculation was based on density functional compact bound (DFTB+) software. The calculated results show that in the stacked system, the complete desolvation size of the TEA+ reaches 5.6 Å, the complete desolvation size of the TEMA+ reaches 4.9 Å, the complete desolvation size of the SBP+ reaches 4.8 Å, and the complete desolvation size of the Li+ reaches 5.4 Å, with the organic electrolyte cations showing a positive trend in the complete desolvation size as the ion radius increases. An in-depth analysis of the data shows that Li+, TEA+, TEMA+, and SBP+ ion radii play a dominant role in the size of desolvation. The results of this paper provide an effective aid for the selection of organic electrolytes to increase the capacity of supercapacitors. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Static time-of-flight secondary ion mass spectrometry (ToF-SIMS) was performed for acquiring the high-resolution surface spectra of four types of synthesized imidazolium ionene membranes. These novel membranes have aromatic ether–ketone–ether linkages inspired by poly(ether ether ketone) (PEEK). The PEEK-ionenes synthesized for this study have imidazolium cations placed in the polymeric backbone with bistriflimide [Tf2N]− counterions. The attention given to synthetically modified PEEK derivatives, such as PEEK-ionenes, is considerable due to their ability to selectively capture CO2 molecules and other light gases. Therefore, it is important to characterize the surface of these synthesized novel PEEK-ionenes. In this work, characteristic and unique peaks were identified in the positive spectra of each sample. The differences in mass spectra among the samples provide insights for optimizing or fine-tuning the PEEK-ionenes synthesis to achieve a high-performance CO2 separation membrane with enhanced permeability, selectivity, and mechanical stability. The SIMS spectra and identified characteristic peaks of these synthesized ionenes will serve as a reference in the positive mode, complementing the corresponding spectra reported in the negative ion mode (Paper II). [ABSTRACT FROM AUTHOR]

Plasma jet normally operates in a regime of positive or negative streamers. Different propagating behaviors have been investigated for positive streamers. However, there are few studies on negative streamers. In this paper, a two-dimensional fluid model is used to simulate the behavior of a negative streamer encountered with a cloud of positive ions. Simulation results indicate that the negative streamer behaves like a free streamer when the ion cloud has a low charge density. After initiation near the needle tip, the streamer propagates along the axis, passes through the ion cloud, and finally reaches the anode vicinity along a straight line. When the streamer reaches the ion cloud, its head radius (R0) is investigated as a function of parameters, including the voltage amplitude and the gap width, as well as the charge density, axial position, and spatial size of the ion cloud. At a given moment, electric field strength and electron density near the streamer head increase with increasing charge density of the ion cloud. In the case of a high charge-density ion cloud, after a primary streamer propagates some distance along the axis, a positive secondary streamer, and a negative secondary streamer start to propagate from the cloud to the cathode and the anode, respectively. [ABSTRACT FROM AUTHOR]

Supercapacitors have a wide range of applications in high-technology fields. The desolvation of organic electrolyte cations affects the capacity size and conductivity of supercapacitors. However, few relevant studies have been published in this field. In this experiment, the adsorption behavior of porous carbon was simulated with first-principles calculations using a graphene bilayer with a layer spacing of 4–10 Å as a hydroxyl-flat pore model. The reaction energies of quaternary ammonium cations, acetonitrile, and quaternary ammonium cationic complexes were calculated in a graphene bilayer with different interlayer spacings, and the desolvation behavior of TEA+ and SBP+ ions was described. The critical size for the complete desolvation of [TEA(AN)]+ was 4.7 Å, and the partial desolvation size ranged from 4.7 to 4.8 Å. The critical size for the complete desolvation of [SBP(AN)]+ was 5.2 Å, and the partial desolvation size ranged from 5.2 to 5.5 Å. As the ionic radius of the quaternary ammonium cation decreased, the desolvation size showed a positive trend. A density of states (DOS) analysis of the desolvated quaternary ammonium cations embedded in the hydroxyl-flat pore structure showed that the conductivity of the hydroxyl-flat pore was enhanced after gaining electrons. The results of this paper provide some help in selecting organic electrolytes to improve the capacity and conductivity of supercapacitors. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chromogenic sensor for selective estimation of aqueous ferric ions was developed. • The chromogenic paper strip was prepared via doping tannic onto filter paper. • A visible color shift from white to purple was observed in the presence of Fe(III). • A concentration range of 10–190 ppm was monitored a detection limit of Fe(III). • The current sensor is a simple and practical tool for real-time detection of Fe(III). Investigation of chromogenic sensor which can selectively estimate ferric cations in aqueous environment with prospect to produce portable platforms is currently proposed. Herein, the chromogenic sensor (Tannic Acid@Filter Paper; TA@FP) was prepared via doping of tannic acid within filter paper to afford the excellent selectivity for ferric cations over various examined metal ions. The designed chromogenic sensor was applied for estimating ferric ions via turn-on detection, while, it could acquire a marked visible color shifting from white to purple hue depending on the total content of Fe (III) ions in the aqueous medium. Complete characterization of the designed sensor before and after its exploitation in estimation of ferric cations was systematically performed via different spectral and microscopic analyses. The functionalized TA@FP was quite sensitive for quantitative estimation of ferric ions with wide scaling linear concentration range of 10–190 ppm. Maximum sensitivity of the exploited platform was observed at very low concentration (10 ppm) rather than the higher concentrations. The correlation coefficient (R2 = 0.99) was closer to unity. The prepared chromogenic sensor could be described as a simple and practical sensing tool for real-time quantitative and qualitative assessment of Fe (III) cations. [ABSTRACT FROM AUTHOR]

The Solar Wind Ion Focusing Thruster (SWIFT) is a highly-innovative propellantless propulsion concept, recently proposed by Gemmer and Mazzoleni. In its nominal configuration, a SWIFT consists of a conically-shaped mesh of positively-charged conducting tethers, with its vertex linked to the spacecraft and its axis oriented towards the Sun. The SWIFT collects and filters the solar wind plasma and suitably directs the positive ions, which are then accelerated by an ion thruster. Such a device is theoretically able to generate a deep-space propulsive acceleration that comes, in part, from the solar wind dynamic pressure impinging on the conical grid and, in part, from the positive ion beam. In particular, the orientation of the ion beam may be chosen in such a way as to set the resultant propulsive acceleration and steer the spacecraft. The aim of this paper is to analyze the performance of a SWIFT-propelled spacecraft in an orbit-to-orbit two-dimensional interplanetary transfer. To that end, some mission scenarios are studied, in an optimal framework, by minimizing the total flight time necessary for the spacecraft to complete the transfer as a function of the propulsion system performance parameters. Numerical simulations are used to compare the optimal flight times calculated in simplified Earth–Venus and Earth–Mars transfers with those obtained by considering other propellantless propulsion systems. [ABSTRACT FROM AUTHOR]

Mixtures of powder and liquid are ubiquitous in nature as well as industries and exhibit complex flowing and deforming behaviors, including sol to gel transition under shear stress. In order to better understand the characteristic features of this type of mixture, we observed the behavior of a mixture of colloidal silica particles and water as a model system under vibration. The mixture showed different states, from powder-like to viscous fluid-like, with increasing content of water. At certain concentrations of silica particles (around 70 wt. %) and under relatively faster vibration (over 17 Hz), we observed that the colloidal suspension of silica particles and water climbed up the wall of a container against gravity. The main purpose of this paper is to report how we can observe the climbing suspension of colloidal silica. The rheological measurements of the climbing suspension demonstrated that the climbing suspension showed shear-thickening behavior, where force chain networks and normal stress differences are considered to develop. Therefore, we speculate that the transient formation and breaking of force networks and normal stress differences under vibration contribute to the occurrence of the climbing suspension. The tunable nature of colloidal suspensions may help to elucidate the climbing mechanism in the future. [ABSTRACT FROM AUTHOR]

An hourly scale precursor of inland earthquakes (EQs) is revealed in this paper. Several EQ cases in China have been reported. As indicated by a table listing 23 inland EQs and their shock time, epicenter location, magnitude, near-epicenter weather conditions, precursor start time and precursor duration, when the weather conditions are fair near the epicenter, an anomalously negative atmospheric electrostatic signal is readily observable approximately 2–48 h before the EQ occurs. Moreover, a successful single-station alarm for nearby moderate-magnitude EQs is demonstrated, and a possible mechanism for the precursor signal is proposed. The change in the electrostatic field during an EQ process is explained as the release of radioactive gases from the subsurface into the atmosphere via large (regional-scale) preexisting microfractures in the rock at the source depth. These gases considerably ionize the atmosphere, and the separated positive and negative ions establish a special macroscopic electric field. The final critical stage of 2–48 h before an EQ may indicate a stable tectonic process. [ABSTRACT FROM AUTHOR]

Red‐emitting color‐convertors have attracted considerable attention for promising applications in solid‐state lighting (SSL) to improve color rendition. However, the current nitride and fluoride phosphor powders have encountered several challenges, such as high cost, narrow emission bands, and insufficient stability during operation, which limit the development of high‐power full‐spectrum SSL. In this study, thermally robust Gd3(Al,Ga)5O12:Mn (GAGG:Mn) solid‐solution ceramics (SSCs) with dual wavelength red‐emission bands were prepared via an oxygen solid‐state sintering reaction. The doped Mn ions occupied octahedral Al3+ and Ga3+ sites to generate Mn4+ luminescent centers with pronounced deep‐red emissions peaking at 698 nm (2E → 4A2), and Mn2+ luminescent centers with broad red emissions at 628 nm (4T1 → 6A1). Because the cationic radius matching effect induced the regulation of valence state of Mn, the photoluminescence of the GAGG:Mn SSCs can be tailored by the substitution of Al3+ with Ga3+. Moreover, the Mn3+ also existed in the GAGG lattice host, and their concentration decreased with increasing Ga3+ contents owing to the mismatch of ionic radius between Mn3+ and Ga3+ ions. With the optimization of Al/Ga ratio and concentration of Mn ions, a broad emission band ranging from 550 to 800 nm (bandwidth = 250 nm) was achieved from Gd3Al3Ga2O12:0.3%Mn SSCs upon 465‐nm excitation. Moreover, the GAGG:Mn SSC has over 17‐fold enhanced thermal conductivity compared with the corresponding phosphor powder. This paper opens a door of regulating the valence state of luminescence centers with cation substitution and the application of oxide red‐emitting color‐convertors. [ABSTRACT FROM AUTHOR]

An elaborate account of groundwater quality estimation for irrigation in Katthiwada area Alirajpur district Madhya Pradesh is presented in this paper. The selected 20 groundwater samples from open-dug wells have been subjected to chemical analysis by standard techniques of graphic representation in tabular form. The analysis of dug wells samples for determination of Physicochemical parameters indicates that all groundwater samples are colourless, odourless, and tasteless with pH (7.0 -8.7), Electrical conductivity (238-1555), Total dissolved solids (450 -1180) mg/l. The chemical parameters involve the determination of the ionic concentration of cations - Calcium (0.89 to 3.04 mg/l), Magnesium (0.49 to 3.12 mg/l), potassium (0.01 to 0.13 mg/l) and sodium (0.95 to 10.35 mg/l) and anion - nitrate (0.56 to 1.45), Hco3 (1.19 to 3.85 mg/l), chloride (0.31 to 5.10) and sulphate (0.02 to 2.68 mg/l). The quality of groundwater for irrigational purposes depends on different chemical parameters such as sodium persent; Kelley's Ratio, Sodium Adsorption Ratio, Residual Sodium Carbonate, and Magnesium-Hazard. U. S. Salinity diagram shows that 19 samples belong to the C2 S1 type (medium salinity - low sodium water), 1 sample represents to C3 S1 type (high salinity - low sodium water) and 1 sample falls into C3 S2. Wilcox diagram shows that 16 samples of the groundwater fall under the excellent to good category, and 4 samples represent the good to permissible categories. The groundwater of the Katthiwada area is suitable for irrigation use. [ABSTRACT FROM AUTHOR]

White light solid-state lighting applications still face significant challenges due to insufficient efficient and stable red light emitting materials. Therefore, a series of orange-red fluorescent materials, CaLu 2-x Mg 2 Si 3 O 12 :xCe3+ (CLMS:xCe3+; x = 0.02, 0.04, 0.06, 0.08, 0.10, 0.12) were prepared in this paper. Luminescence spectra testing revealed that the optimal concentration of Ce3+ ions in the crystal lattice is x = 0.04. At 460 nm excitation, the emission wavelength is approximately 592 nm. To enhance the thermal stability and luminescence performance of CLMS:Ce3+, the CaLu 1.96-y Me y Mg 2 Si 3 O 12 :0.04Ce3+ (Me = Sr, Ba; y = 0, 0.02, 0.05, 0.10, 0.15, 0.20) fluorescent materials were successfully prepared. It was found that phosphor's fluorescence intensity was enhanced after the introduction of Sr2+ or Ba2+ ions. Meanwhile, the phosphors were tested for thermal stability, and the emission intensities of CLMS:0.04Ce3+, CLMS:0.04Ce3+,0.10Sr2+, and CLMS:0.04Ce3+,0.05Ba2+ phosphors decreased to 77.60%, 85.53%, and 87.63% at 423 K, respectively. This proves that Sr2+ and Ba2+ ions have a positive effect on the thermal stability performance of CLMS:0.04Ce3+ phosphor. Testing of the w-LED devices, the CCT was reduced. The CRI was improved to 80.4 and 81.6 and luminescence efficiency was improved to 107.71 lm/W and 115.04 lm/W after Sr2+ or Ba2+ ions were introduced. In summary, this study demonstrates that CaLu 2-x-y Me y Mg 2 Si 3 O 12 :xCe3+ (Me = Sr, Ba) is an auspicious fluorescent material with high thermal stability, which is potentially informative for the field of white-light illumination. [ABSTRACT FROM AUTHOR]

The presence of reactive hydrogen-silyl (SiH) bonds in oligomethylhydridesiloxanes provides their widespread use in the building, paper, textile, and rubber industries. Low-molecular fractions of methylhydridesiloxanes, both cyclic and linear, adversely affect the operational properties of oligomer-based materials. The main goal of the present study is detection and identification of these fractions in a 136-157M commercial product, as well as in the co-oligomers synthesized from it. The method of gas chromatography–mass spectrometry has been used in the study. First, it has been proved that an increase in the temperature of the column and evaporator from 60 to 300°C does not change the composition of the low-molecular fractions. Consequently, there is no depolymerization processes related to the formation of low-molecular compounds during the analysis. To perform a qualitative analysis, the components of low-molecular fraction have been separated on a capillary column and then identified using a mass detector with an ion trap. It is shown that electron ionization triggers fragmentation of molecules and the formation of positively charged ions. As for methylhydridesiloxanes, cations with a molecular weight of [M – 15]+ arising from the rupture of the carbon-silyl bond are formed first. When such a rupture occurs in cyclosiloxanes with a total number of units of more than four, further dissociation processes can occur with the detachment of the neutral fragment (methylsilane) and the formation of bicyclosiloxane cations. Since the set of positive ions is individual for each of the components and depends on , a component-wise description of the entire low-molecular fraction becomes possible with a high degree of reliability. It is shown that, for the commercial sample under consideration, it can be described by two homologous series: cyclic , where m ≥ 4, and linear siloxanes , where n ≥ 1. [ABSTRACT FROM AUTHOR]

The ability of humus substances to form stable complexes with inorganic and organic soil constituents plays a vital role in the generation of environmental pollution, migration, and pollutants transformation. This paper deals with the study of the sorption of metallic elements (Al, Ca, Cu, Fe, K, Mn, Mg, Zn) in Andosols, Cambisols, and Planosols on Slovak soil types based on the detection of the quality and quantity of humus substances and soil textural properties. Five soil profiles from two areas in the central part of the Western Carpathians on volcanic rocks in Slovakia were investigated. HS values increased with Al, Ca, Cu, Fe, K, and Mg. Fe, Al, Ca, Mg, K, Mn, Cu, and Zn increased with the FA fraction. Al, Ca, Fe, K, and Mg were increasing with increasing HA values. In the HA fraction, a very tight relationship was among K and Fe contents (r = 0.902). In the FA fraction, we found with increasing Cu content, Ca content also increased (r = 0.959). The HS values were positively correlated with the silt and negatively correlated with the clay and the sand fraction. Only the elements Mn and Zn in Planosol were below the detection limit. High concentrations of metallic elements were in Andosol. [ABSTRACT FROM AUTHOR]

To quantitatively describe the kind of interaction between ion and solvent, it is convenient to use the concept of negative or positive solvation. We have established earlier that diffusion displacement distance ( d ¯ ) of an ion correlates with its solvation type. The ion is solvated positively if the average d ¯ value exceeds the crystallographic (structural) radius of an ion r i ; otherwise, ion solvation is negative. In this paper, we have estimated the length, time and velocity of ion diffusion displacement (hop) for singly charged ions Li + , Na + , K + , Rb + , Cs + , Me 4 N + , Et 4 N + , Bu 4 N + , F - , Cl - , Br - , BPh 4 - over the temperature range from 273.15 K to 473.15 K and for ions Pr 4 N + , I - , NO 3 - , ClO 4 - at 298.15 K in ethylene glycol. The fact of the negative solvation of almost all ions studied (except Li + , Na + , F - ) in ethylene glycol has been established for the first time. It has been shown that Me 4 N + ion has turned out solvated solvophilically in EG as well as in water while ions Et 4 N + , Bu 4 N + , and BPh 4 - appeared to be solvated solvophobically. We have estimated the temperature of transition T tr (from negative to positive ion solvation) for K + and Rb + ions. It physically corresponds to the absence of solvation of the ion ( d ¯ = r i ). [ABSTRACT FROM AUTHOR]

The paper deals with the gas-phase formation of nanoparticles that is a fundamental process responsible for the condensed matter in the Universe, which also attracts attention due to its involvement in the particle synthesis for various nanotechnology applications. Previously reported results on MgO nano-oxides formed by Mg combustion showed a unique phenomenon coined "the condensation stagnation" that is the occurrence of critical clusters with suppressed growth. Here we focus on the effect of an external ionizer on this condensation growth stagnation. We show that the condensation stagnation occurring in the Mg particle flame subjected to a positive ion flux is similar to that in the unaffected flame. In contrast, applying negative charging significantly influences the state of stagnation of the system, i.e., no critical clusters are observed in the products sampled from the flame. The discovered critical behavior of the state of stagnation is explained in terms of the heat transfer between the condensed MgO nanoparticles and the surrounding gas, which efficiency depends on the sign of the nanoparticle charge. This dependence of the heat transfer efficiency on the nanoparticle charge is a new fundamental effect that should become the basis for accurate modeling in two-phase high-temperature systems. [ABSTRACT FROM AUTHOR]

In this paper, the corona discharge process of the bar-plate gap at −1 kV DC voltage is simulated using a two-dimensional axisymmetric plasma module. We analyze the variation of air negative corona discharge current, and the distribution morphology of microparticles in different discharge stages in detail. The significance of plasma chemical reactions at some typical time and the distribution characteristics of heavy particles are investigated according to reaction rates. Results show that, in the current rising stage, the collision ionization reactions (e.g., R1 and R2) and electron adsorption reaction (e.g., R3) play a major role, which lead to the increase in charged particles and the formation of an electron avalanche. In the current drop stage, all reaction rates decreased, except for collision ionization and electron attachment, partial charge transfer reactions (e.g., R8, R10, R11, and R14), and composite reactions (e.g., R16, R17, and R18), which come into play and gradually reduce the number of charged ions in the gap. In the current stabilizing stage, the main chemical reactions are composite reactions (e.g., R16 and R17), then the corona discharge ends. For the heavy particle distribution, O2+ and O4+ are the main positive ions, O2− is the most abundant negative ions, and the neutral particles are mainly O. [ABSTRACT FROM AUTHOR]

Due to their good dielectric properties and low global warming potential, C4F7N–CO2 and C4F7N–N2 mixtures have shown promising potential to replace SF6 in high voltage gas insulated equipment. However, during manufacturing, installation, and transportation of power equipment, burs and metal particles can be inevitably left inside, and they can cause corona discharge. Fundamental investigation of the corona discharge mechanism is essential to monitor partial discharge signals in environmentally friendly power equipment. This paper applies the fluid model to investigate the discharge mechanism of C4F7N–CO2 and C4F7N–N2 mixtures in negative point-plane corona discharge. A 2D axisymmetric model combines the drift-diffusion equations for electrons, positive ions, and negative ions and Poisson's equation to study the process of dynamics. The gas is a mixture of C4F7N (5%, 7%, or 13%) and CO2 or N2 (95%, 93%, or 87%). The rise time of the first discharge pulse in C4F7N–CO2 and C4F7N–N2 mixtures is about 0.1 ns. The interval time between the first and the second pulse in the 5% C4F7N–95%CO2 mixture is about 1.5 times longer than that in the 5% C4F7N–95% N2 mixture. When the C4F7N content is 7% and 13%, the interval time between the first and second pulses in C4F7N–CO2 mixtures is about 2 and 3 times longer than those in C4F7N–N2 mixtures, respectively. The suppression regions in C4F7N–CO2 mixtures are larger than those in corresponding C4F7N–N2 mixtures. The total number of electrons, positive ions, and negative ions in C4F7N–CO2 mixtures is higher than that in C4F7N–N2 mixtures, while the reduced electric field in C4F7N–CO2 mixtures is smaller than that in C4F7N–N2 mixtures. [ABSTRACT FROM AUTHOR]

This paper presents the systematic studies of the sorption capacity of natural zeolite with respect to In3+ and Ga3+ cations in the model systems "natural zeolite–In3+–H2O" and "natural zeolite–In3+–Ga3+–H2O", while varying a number of the main process factors. The patterns of sorption of In3+ and Ga3+ cations by the natural zeolite of the Shankanai deposit are revealed, depending on the zeolite vs. solution ratio, temperature, and time. It is shown that the sorption of In3+ cations by natural zeolite can be controlled by the process duration. The longer the process, the less the sorption by natural zeolite. It has been found that the sorption of In3+ cations in the "natural zeolite–In3+–Ga3+–H2O" model system depends on the amount of zeolite and temperature, and the sorption of Ga3+ cations depends on the temperature and time. The physicochemical characteristics of the spent sorbents confirm the sorption of the cations, present in the systems under study. [ABSTRACT FROM AUTHOR]

In this paper cation arrangement in two samples of aluminoceladonite, emerald-green and dark-green were studied by Mössbauer, Raman and X-ray photoelectron spectroscopies. The X-ray photoelectron spectroscopy (XPS) spectra obtained in the region of the Si2p, Al2p, Fe2p, K2p, and O1s core levels provided information, for the first time highlighting a route to identify the position of Si, Al, K, and Fe cations in a structure of layered silicates. The XPS analysis showed the presence of Al in tetrahedral and octahedral coordination while the K2p line indicated the possibility of K+ substitution by other cations in interlayer sites. Mössbauer spectroscopy provided information about crystal chemistry with respect to the local electronic and geometric environment around the Fe atom and to distortions of the polyhedra. It turned out that iron was located mostly in the cis-octahedra position wherein about 75% of iron appeared in the form of Fe3+. The most preferred cation combinations around Fe corresponded to 3Fe3+ ions and MgFe2+Fe3+/2MgFe3+. Raman spectroscopy illustrated aluminium substitution in silicon and iron positions wherein the concentration of the aluminium determined the degree of structural distortion within the layered system. These isomorphic substitutions implied a typical band arrangement in the hydroxyl region, which has not been observed in celadonites so far. [ABSTRACT FROM AUTHOR]

This paper describes the construction of the Periodic Tables for cations of all elements with charges + 1, + 2, + 3 and anions with charge − 1. The Table for cations+1 differs significantly from other newly constructed Tables and from known Tables, as the d- and f-blocks are inserted into s-block and split it up for two parts. Importantly, a new type of 3d- and 4f-shell contractions has been discovered. The manifestations of secondary periodicity in case of anions is absent or opposite to the manifestations observed for atoms and cations. For kainosymmetric anions, the ionization energies are lowered, which contradicts the theoretical assumptions and experimental data supporting the classical concept of kainosymmetry. Simple formulas are proposed for quantitative description of the manifestations of internal periodicity and kainosymmetry. The regularities of change in these manifestations depending on the charge and the position of ions or atoms in the Periodic Table are established. In the 6th period, the bifurcation in the properties characteristic of the internal periodicity does not occur at usual position, i.e. in the middle of the row from the block of the Periodic Table (p3–p4), but takes place earlier, along with the transition of the electronic configurations p2–p3. In other words, the place of transition from "early" to "late" elements changes. [ABSTRACT FROM AUTHOR]

Due to the fact that surfactant molecules are known to alter the structure (and consequently the function) of a protein, protein-surfactant interactions are very important in the biological, pharmaceutical, and cosmetic industries. Although there are numerous studies on the interactions of albumins with surfactants, the investigations are often performed at fixed environmental conditions and limited to separate surface-active agents and consequently do not present an appropriate comparison between their different types and structures. In the present paper, the interactions between selected cationic, anionic, and nonionic surfactants, namely hexadecylpyridinium chloride (CPC), hexadecyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), polyethylene glycol sorbitan monolaurate, monopalmitate, and monooleate (TWEEN 20, TWEEN 40, and TWEEN 80, respectively) with bovine serum albumin (BSA) were studied qualitatively and quantitatively in an aqueous solution (10 mM cacodylate buffer; pH 5.0 and 7.0) by steady-state fluorescence spectroscopy supported by UV spectrophotometry and CD spectroscopy. Since in the case of all studied systems, the fluorescence intensity of BSA decreased regularly and significantly under the action of the surfactants added, the fluorescence quenching mechanism was analyzed thoroughly with the use of the Stern-Volmer equation (and its modification) and attributed to the formation of BSA-surfactant complexes. The binding efficiency and mode of interactions were evaluated among others by the determination, comparison, and discussion of the values of binding (association) constants of the newly formed complexes and the corresponding thermodynamic parameters (Δ G , Δ H , Δ S ). Furthermore, the influence of the structure of the chosen surfactants (charge of hydrophilic head and length of hydrophobic chain) as well as different environmental conditions (pH, temperature) on the binding mode and the strength of the interaction has been investigated and elucidated.

In this paper, functionalized sodium alginate hydrogel (FSAH) was prepared to efficiently adsorb heavy metals and dyes. Hydrazide-functionalized sodium alginate (SA) prepared hydrazone groups to selectively capture heavy metals (Pb2+, Cd2+, and Cu2+), and another functional group (dopamine grafting), serves as sites for adsorption methylene blue (MB), malachite green (MG), crystal violet (CV). Thermodynamic parameters of adsorption indicated that the adsorption process is endothermic and spontaneous. The heavy metals adsorption by FSAH was physical adsorption mainly due to ΔHθ < 40 kJ/mol, and the adsorption of cationic dyes fitted with the Langmuir models, which indicated that the monolayer adsorption is dominated by hydrogen bonds, electrostatic interactions, and π-π interactions. Moreover, the adsorption efficiency maintained above 70% after five adsorption-desorption cycles. To sum up, FSAH has great application prospect. [ABSTRACT FROM AUTHOR]

This paper explores the head-on collision between two-counter propagating positron acoustic solitons and double layers (DLs) in an unmagnetized collisionless plasma having mobile cold positrons fluid, immobile positive ions and ( r , q )-distributed hot positrons, and hot electrons. By employing the extended Poincaré–Lighthill–Kuo method, the coupled Korteweg–de Vries (KdV), modified KdV (mKdV) and Gardner equations are derived to archive this goal. The effect of dimensionless parameters on the propagation characteristics of interacting KdV solitons (KdVSs), mKdV solitons (mKdVSs), Gardner solitons (GSs) and DLs are examined in detail by considering the limiting cases of ( r , q )-distribution. It is noted that the interaction of GSs and DLs are reported for the first time. The outcomes might be comprehended and beneficial not only in space and astrophysical environments but also in laboratory studies. [ABSTRACT FROM AUTHOR]

The experimental data reported in this paper suggest that titanium(IV) oxyhydroxyphosphate-based ion-exchange materials are potentially attractive for extraction of heavy metal cations from solutions. We have studied the time-dependent ion exchange activity of titanium phosphates for Zn2+, Co2+, and Ni2+ cations in relation to the liquid : solid ratio, temperature, and equilibrium pH of the cation exchange process. The results demonstrate that the selectivity of an ion exchanger for metal cations is determined by the ionic radii of the metals. Conditions for effective use of titanium phosphate materials for extraction of Zn2+, Co2+, and Ni2+ cations from solutions (liquid : solid ratio, temperature, and pH) have been optimized experimentally. [ABSTRACT FROM AUTHOR]

This paper reports the effect of different cations (Na, Mg and Li) while keeping perchlorate as the common anion on ion-dynamics behavior within polymer gel electrolytes containing tetraethylene glycol dimethyl ether (TEGDME) solvent and poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP) as the polymer host. FTIR investigations demonstrate significant changes in characteristic bands, while XRD observations indicate prominent structural variation in terms of merger/suppression of phases when NaClO4, Mg(ClO4)2 and LiClO4 salts are immobilized in the PVdF-HFP/TEGDME matrix. The highest room temperature ionic conductivity of 1.2 × 10−3 S cm−1 with high dielectric constant value has been obtained for the Li+ conducting electrolyte composition due to its superior electrochemistry and ion-conduction behavior as compared to its Na+ and Mg2+ counterparts. In the low-frequency region, modulus curves reveal polarizing effects with long-range mobility/migration of Na/Mg/Li ions, while in the high-frequency region, a peak onset relating the translational ion dynamics and conductivity relaxation is observed. The reported polymer gel electrolytes may be employed as electronic materials for developing next-generation flexible electrochemical devices. [ABSTRACT FROM AUTHOR]

The results reported in this paper suggest that titanium(IV) oxyhydroxyphosphates can be used for sorption extraction of valuable metal cations from solutions, followed by desorption and concentration of the metal cations and simultaneous regeneration of the titanium phosphate material for further use. Conditions for effective desorption processes (desorbing agent concentration and desorption time) have been studied and optimized. The sorption/desorption process effectiveness in the case of multistep use of the sorbent has been shown to decline as a result of steric hindrances associated with its dehydration. As the sorption properties of the sorbent degrade, it can be used for extraction of trace amounts of highly toxic metal cations and then buried. [ABSTRACT FROM AUTHOR]

Negative corona discharge can deflect in transverse airflow in pin-to-plane electrodes at atmospheric pressure. In this paper, we investigate the mechanism of Trichel pulse discharge deflection in transverse airflow and give a further understanding of the dynamic process of the deflection through experiments and simulations. In experiments, we quantitatively record the deflection angle by processing the discharge images, and they show that a larger airflow speed will lead to a larger deflection angle. In simulations, the discharge deflection angle is calculated through a 2D fluid model. Besides, the periodic fluctuation of the deflection angle with Trichel pulses is revealed, and this phenomenon can be explained by the alternative dominant effect of airflow or ionization on the net production of positive ions in the vicinity of the tip. When the effect of airflow is dominant, more positive ions will generate away from the center of the tip, which will lead to an increase in the deflection angle. On the other hand, when the effect of ionization prevails, more positive ions will generate near the center because the electric field here is stronger, and the deflection angle will decrease. In addition, if these two effects balance, the deflection angle will reach its maximum or minimum value. [ABSTRACT FROM AUTHOR]

This paper demonstrates the feasibility of using titanium(IV) oxyhydroxyphosphate-based materials for sorption extraction of heavy metal cations from solutions. We have determined Pb2+ and Cd2+ sorption characteristics of ion exchangers, examined the kinetics of Pb2+ and Cd2+ sorption on the titanium phosphate materials, and assessed the effect of ionic radius on the affinity of the sorption matrices for metal cations. Conditions for effective use of the ion exchange materials for extracting Pb2+ and Cd2+ cations from solutions (liquid : solid ratio and pH) have been optimized experimentally. [ABSTRACT FROM AUTHOR]

This paper presents the behaviour of cation and anion in samples of water collected from the coastal blocks of Tiruvallur District, Tamilnadu, India. 13 physiochemical parameters are investigated on the uniformly collected groundwater samples. It is revealed that fifty percentage of groundwater samples surpassed water quality levels pertaining to drinking and irrigation. In this investigation, descriptive statistical analysis is performed to understand groundwater characteristics. The hydro-chemical dynamics of groundwater are evaluated using graphical plots Piper, Wilcox, and Gibbs. Through the Piper plot, it is concluded that high concentrations of sodium would induce cation exchange between Ca2+ and Mg2+ from the soil. This may lead to the acceleration of air and water circulation through the soil in wet conditions. The inference of the Piper plot is supported by end result of Gibbs plot. Gibbs plot indicates evaporation dominance of anthropogenic activities, while Wilcox plot clearly indicates groundwater's suitability for irrigation purposes. Moreover, the cation concentration is seen to be high on the eastern portion of the chosen area. The level of groundwater treatment should be adequately determined for potable purposes and for agricultural purposes as the study concludes the intrusion of saline water, rock water interaction and irrigation flows. [ABSTRACT FROM AUTHOR]

Ternary metal oxide compounds, such as Ti-Nb and Nb-W oxides, have renewed research interest in energy storage materials because these oxides contain multivalent metal ions that may be able to control the ion transport in solid lithium batteries. One of these oxides is Ti2Nb10O29, which is composed of metal–oxygen octahedra connected through corner-sharing and edge-sharing to form "block structures". In the early 1970s Von Dreele and Cheetham proposed a metal-atoms ordering in this oxide crystal using Rietveld refined neutron powder diffraction method. Most recent studies on these oxides, however, have not considered cation ordering in evaluating the battery electrode materials. In this paper, by utilizing the latest scanning transmission electron microscopy combined with energy dispersive X-ray spectroscopy imaging technology, the cation chemical ordering in those oxide crystals was directly revealed at atomic resolution. [ABSTRACT FROM AUTHOR]