Effect Of Sodium Ion Concentration Research Articles

Probing the Mechanism of Improved Performance for Sodium-ion Batteries by Utilizing Three-electrode Cells: Effects of Sodium-ion Concentration in Ionic Liquid Electrolytes

We investigated the full-cell performance of sodium-ion batteries composed of a hard carbon (HC) negative electrode, a NaCrO2 positive electrode, and an ionic liquid electrolyte Na[FSA]–[C3C1pyrr][FSA] (FSA = bis(fluorosulfonyl)amide, C3C1pyrr = N-methyl-N-propylpyrrolidinium) at 333 K. Before the full-cell tests, charge–discharge tests of the Na/HC and Na/NaCrO2 half cells were conducted, from which the practical capacities were determined to be ca. 250 mAh (g-HC)−1 and ca. 115 mAh (g-NaCrO2)−1, respectively. Using these capacities, the performance of HC/NaCrO2 full cells with practical loading masses was evaluated by three-electrode cells with a sodium metal reference electrode, and the energy density was calculated to be 177 Wh (kg-(NaCrO2 + HC))−1. In particular, we focused on the effect of the sodium-ion concentration on the performance by varying the molar fraction of Na[FSA] (x(Na[FSA])) from 0.20 to 0.50. The best rate capability was obtained at a composition of x(Na[FSA]) = 0.50. The effect of the sodium-ion concentration was discussed in terms of the potential profiles of the positive and negative electrodes. The results were explained by the sodium-ion supplying capability of the electrolyte inside the electrode, where the sodium insertion reaction occurs.

Diversified Li1.2Ni0.2Mn0.6O2 nanoparticles from birnessite towards application specificity and enhancement in lithium-ion batteries

In the present work, three types of Li1.2Ni0.2Mn0.6O2 were synthesized from sodium birnessite (NaBir) and each type exhibited distinct morphological features created by varying preparation (with or without ball milling) or varying the sequential order of the preparation steps. Three processes were employed, including (1) ion-exchange, simply mechanical mixing, calcination (Without-BM), (2) ion-exchange, ball milling, calcination (EX-priority), (3) ball milling, ion-exchange, calcination (BM-priority). The three as-prepared sample types exhibited different performance characteristics, depending on their respective preparation processes. The “Without-BM” sample exhibited a reversible capacity of 240mAhg−1 between 2.0V and 4.8V with a current density of 0.1C (30mAg−1), having almost no capacity fading after 80cycles. The “EX-priority” sample exhibited a desirable rate performance with a reversible capacity of 213.4mAhg−1 at 1C and 136.4mAhg−1 at 7C; however, the capacity retention was 88.3% after 80cycles at 0.1C. The “BM-priority” sample displayed a moderate rate and cycle performance. The differences between these samples demonstrated that the ball milling treatment and its sequence have substantial effects on performance of materials. The experimental data indicated that the different performances can be attributed to the different morphologies of the respective materials as well as the effect of sodium ion concentration within the structure. Therefore, controlling the morphology of the material and the amount of sodium ions in its structure may be advantageous for developing high quality cathode materials which can be diversified for specific applications in Li-ion batteries.

Role of Sodium Channel on Cardiac Action Potential

Sudden cardiac death is a major cause of death worldwide. In most cases, it's caused by abnormal action potential propagation that leads to cardiac arrhythmia. The aim of this article is to study the abnormal action potential propagation through sodium ion concentration variations. We use a new electrophysiological model that is both detailed and computationally efficient. This efficient model is based on the partial differential equation method. The central finite difference method is used for numerical solving of the two-dimensional (2D) wave propagation equation. Simulations are implemented in two stages, as a single cardiac cell and as a two-dimensional grid of cells. In both stages, the normal action potential formation in case of a single cell and it's normal propagation in case of a two-dimensional grid of cells were simulated with nominal sodium ion conductance. Then, the effect of sodium ion concentration on the action potential signal was studied by reducing the sodium ion conductance. It is concluded that reducing the sodium ion conductance, decreases both passing ability and conduction velocity of the action potential wave front.

Resorcinol-formaldehyde coated XAD resin beads for removal of cesium ions from radioactive waste: synthesis, sorption and kinetic studies

A novel synthetic method was developed to synthesize resorcinol-formaldehyde (RF) resin in spherical form, of required mesh size, using XAD-4 as template beads. The synthesized RF-coated XAD (RF-XAD) beads were characterized, using different techniques. Suitable size and mechanical stability, along with their spherical shape, make these beads most appropriate for column operation. The efficiency of these beads was evaluated for removal of cesium from alkaline medium, in batch conditions, using a radioanalytical technique. The effect of sodium ion concentration, the initial cesium ion concentration and the contact time were also investigated. It was observed that the Kd value for Cs+ ions decreases with increase in Na+ ion concentration. The equilibrium data were fitted into different isotherm models, and were found to be represented well by the Langmuir isotherm equation, with a monolayer sorption capacity of 287 mg g−1. Kinetic modeling analysis, using pseudo first-order, pseudo second-order and intraparticle diffusion equations, shows that the pseudo second-order equation is the most appropriate model for the description of the sorption of cesium ions onto the RF-XAD beads. The rate constants were determined at different initial concentrations. The process mechanism was found to be complex, consisting of both surface sorption and pore diffusion.

Effect of Sodium Ion Concentration on Hydrogen Production from Sucrose by Anaerobic Hydrogen-producing Granular Sludge

This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L −1(Na +), on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the optimum sodium ion concentration [1000–2000mg·L −1(Na +)] for hydrogen production at 37°C, the maximum sucrose degradation rate, the specific hydrogen production yield and the specific hydrogen production rate were 393.6–413.1mg·L −1·h −1, 28.04–28.97ml·g −1, 7.52–7.83ml·g −1·h −1, respectively. The specific production yields of propionate, butyrate and valerate decreased with increasing sodium ion concentration, whereas the specific acetate production yield increased, meanwhile the specific production yields of ethanol and caproate were less than 55.3 and 12.6mg·g −1, respectively. The hybrid fermentation composition gradually developed from acetate, propionate and butyrate to acetate with the increase in sodium ion concentration.

The effect of sodium ion concentration and dissolved wood components on the kraft pulping of softwood

The effect of ionic strength and dissolved wood components (DWC) in form of industrial black liquor on the delignification rate and the brightness of the unbleached softwood kraft pulp has been inv ...

Thermodynamics of RNA hairpins containing single internal mismatches.

Thermodynamic parameters and circular dichroism spectra are presented for RNA hairpins containing single internal mismatches in the stem regions. Three different sequence contexts for the G*U mismatch and two contexts for C*A, G*A, U*U, A*C and U*G mismatches were examined and compared with Watson-Crick base-pair stabilities. The RNA hairpins employed were a microhelix and tetraloop representing the Escherichia coli tRNAAlaacceptor stem and sequence variants that have been altered at the naturally occurring G*U mismatch site. UV melting studies were carried out under different conditions to evaluate the effects of sodium ion concentration and pH on the stability of mismatch-containing hairpins. Our main findings are that single internal mismatches exhibit a range of effects on hairpin stability. In these studies, the size and sequence of the loop and stem are shown to influence the overall stability of the RNA, and have a minor effect on the relative mismatch stabilities. The relationship of these results to RNA-ligand interactions involving mismatch base-pairs is discussed.

Seventeen new 14- and 15-crown-formazans: their synthesis and evaluation in spectrophotometric determination of lithium

A number of new crown-formazans with 14 and 15 membered rings have been synthesized, characterized and investigated as selective spectrophotometric chelating agents for lithium. The effect of sodium ion concentration on the background lithium signal was studied. A comparative study for the sensitivity of these new crown-formazans in spectrophotometric determinations was studied and compared with those reported previously. The three new 14- and 15-crown-formazans 4a– c containing the pyridyl N-oxide at the formazyl carbon showed the highest selectivity to lithium determination in the presence of sodium ion.

Synthesis of New 14- and 15-Crown-Formazans and their Evaluation in Spectrophotometric Determination of Lithium

The two new crown-formazans 1 and 2 with 14-and 15-membered rings have been synthesized, characterized and investigated as a selective spectrophotometric chelating agents for lithium. The effect of sodium ion concentration on the background lithium signal was studied. Sodium causes depression of the lithium signal and the relative effect diminishes as the total sodium concentration is increased. In a background sodium containing 140 mM sodium, a 10 mM increment of sodium is equivalent to 0.0017 mM Lithium using compound 1 and 0.0024 mM using compound 2.

The Effect of pH and Ionic Strength on the Release of Quinine Adsorbed on to an Insoluble Sodium Polyphosphate

AbstractThe preparation and evaluation of a potential prolonged-release drug delivery system with the model drug quinine HCl adsorbed onto an insoluble sodium polyphosphate (Maddrell's phosphate type II) is described. The delivery system was prepared by equilibration of the drug with a suspension of the polyphosphate and then compressing the dried adsorbed complex into disks. It was shown that the extraction of the drug from the loose powder was enhanced by increasing the sodium ion concentration and by reducing the pH. The effect of sodium ion concentration upon release of the drug from compressed dish depended upon the pH of the dissolution fluid. At low pH, which slowly dissolved the disks, the zero-order release of quinine was reduced as the ionic strength of the dissolution medium was increased. At near-neutral pH, the release of quinine was first-order at sodium concentrations greater than 0.025 M and was zero-order at sodium concentrations lower than 0.025 M. The release was promoted by an increase...

The effect of sodium ion concentration on intrastrand base-pairing in single-stranded DNA.

The salt-induced formation of duplex structure (primarily hairpin loops) in denatured calf thymus DNA was monitored by measuring the decrease in absorbance at 260 nm as a function of increasing sodium ion concentration. It was found that this process was noncooperative and could be accurately described by the mass-action expression for the reversible formation of a binary complex: single strand (coil) + free sodium ion <==> hairpin (with associated sodium ion). The equilibrium constant for the transition was found to be 6 (M Na+)-1. The extrapolated absorbance at infinite salt concentration represents 11% hyperchromicity, which is one third of the hyperchromicity of denatured DNA in the absence of salt (36%).

Mechanism of intercalation: ion effects on the equilibrium and kinetic constants for the interaction of propidium and ethidium with DNA.

AbstractThe effects of sodium ion concentration on the binding isotherms and association and dissociation reaction rates for the interaction of the closely related intercalating dication, propidium, and the monocation, ethidium, with DNA have been determined by spectrophotometric binding and stopped‐flow kinetics methods. The binding of propidium to DNA is best described by a neighbor‐exclusion binding isotherm (two base pairs per binding site) with negative ligand cooperatively on binding. The cooperativity parameter is fairly independent of salt concentration, while the log of the observed equilibrium binding constant varies with −log [Na+], with a slope of two for the propidium–DNA interaction. These effects of the sodium ion on the equilibrium binding of propidium with DNA are similar to those previously described for the dication, quinacrine [Wilson, W.D. &amp; Lopp, I.G. (1979) Biopolymers, 18, 3025–3041]. Ethidium behaves, as a function of salt, as a monocation binding to DNA with neighbor exclusion and without ligand cooperativity. Equations are derived for two limiting kinetics models for intercalation involving binding of the intercalator to a preequilibrium, open state of DNA (model I) or binding form a preequilibrium externally associated state of the intercalator with DNA (model II). Model II gives the best fit to all of the kinetic results if it is assumed that the initial external interaction of the intercalator with DNA is similar to the exchange of free and condensed simple counterions. Intercalation then occurs from this state following an opening transition of the base pairs of the double helix. This model predicts a larger effect of salt concentration on the association than on the dissociation reaction, and that is what is experimentally observed. The intercalation conformational change makes a significant contribution to the ionic effects for both the equilibrium binding and the kinetic constants. The dissociation results and the association reaction results under pseudo‐first‐order conditions could be fit with single exponential curves under the conditions of our experiments.

The effect of sodium ion concentration on the electroretinogram of the isolated retina of the frog.

The Journal of PhysiologyVolume 167, Issue 1 p. 156-168 ArticleFree Access The effect of sodium ion concentration on the electroretinogram of the isolated retina of the frog D. I. Hamasaki, D. I. HamasakiSearch for more papers by this author D. I. Hamasaki, D. I. HamasakiSearch for more papers by this author First published: 01 June 1963 https://doi.org/10.1113/jphysiol.1963.sp007138Citations: 32AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume167, Issue1June 1, 1963Pages 156-168 RelatedInformation