Properties Of NaCl Research Articles

The structural, mechanical and optical properties of NaCl:Eu2+ crystal grown by the Czochralski method

The structural, mechanical and optical properties of NaCl:Eu2+ crystal grown by the Czochralski method

Improved Superconducting Properties of NaCl Doped MgB2

MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> superconducting materials have important application potential in the 20K temperature region, which is a significant advantage compared with other low-temperature superconductors (such as Nb-Ti and Nb3Sn). However, there is a big gap between its superconducting current-carrying capacity and Ni-Ti and Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn, which is due to the weak magnetic flux pinning force and the poor connection between the MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> grains. Chemical doping is a simple and effective method to improve the performance of MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> . This paper studies the effect of NaCl doping on the performance of MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> . It is found that NaCl doping has a positive effect on improving the interconnection of MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> grains and refining MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> grains, and is a potentially effective method to improve the superconducting properties of MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> . In addition, all of the samples in this study showed surface pinning characteristics, but the smaller the MgB <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> grain size, the better the match with the surface pinning characteristics described by Kramer's theory.

The study of ionic interactions of monovalent electrolytes in aqueous polyvinyl alcohol and polyacrylamide by conductance method

The electrical conductivity (Κ), molar conductivity (Λm), and limiting molar conductivity (Λmo) of NaCl and KCl in different compositions of aqueous PVOH and PAAM (0.1%, 0.5%, and 1.0% w/v considering the solubility of PVOH and PAAM in water) were determined at temperatures from 298 to 318 K with a difference of 5 K. The concentration of NaCl and KCl was from 2.0 to 10.0 × 10−3 mol.dm−3. The electrical conductivity of KCl was higher than NaCl. The electrical conductivity increased with the increase in concentration of NaCl and KCl, while a reverse trend was observed for the molar conductivity. The electrical conductivity and molar conductivity increased with the increase of temperature and concentration of polymer in the solvent. The change in conductive properties of NaCl and KCl in aqueous PVOH and PAAM was used to evaluate the fundamental changes inside the solution at the molecular level. The degree of dissociation and dissociation constant decreased with the increase of temperature due to the exothermic nature of the dissociation of NaCl and KCl. The ion-ion and ion-solvent interactions were evaluated by the Debye-Huckel relation. The ion-ion interaction (A) decreased, while the ion-solvent interaction (B) increased with the increase of temperature. The thermodynamic parameters for the dissociation of NaCl and KCl were also determined to understand the energetics and spontaneity of the process. The results are explained in terms of electrostatic interactions, structural effects, and energetics of the processes involved.

The thermodynamic properties of solutions and phase equilibria in the water-2-butanol-sodium chloride system

Fragments of the phase diagram of the H2O-2-C4H9OH-NaCl system were studied experimentally at 298 and 313 K. The thermodynamic properties of sodium chloride in three-component solutions with ionic strengths up to 1.9 mol/kg and alcohol content in the solvent 4.97 and 10 wt % were measured at 298 and 323 K by the electromotive force method with ion-selective electrodes. The eNRTL (electrolyte Non-Random Two-Liquids) model parameters correctly describing the results of electrochemical measurements of the partial properties of NaCl and phase equilibria in the water-2-butanol-sodium chloride ternary system and binary subsystems constituting it were determined. The isothermal sections of the phase diagram of the H2O-2-C4H9OH-NaCl system were calculated using the method of convex hulls implemented in the TernAPI package.

Effects of temperature and pressure on the thermal expansion of sodium chloride

Molecular dynamics (MD) simulations of bulk sodium chloride (NaCl) have been carried out at high pressure and temperature with the objective of establishing and validating the methodology for predicting its temperature- and pressure-dependent thermal expansion behavior. Two different potential models that consist of Coulomb, dispersion and repulsion interactions from the literature have been applied to investigate the volume thermal expansivity of NaCl in the NPT ensemble with periodic boundary conditions: the shell model (SM) potential and the two-body rigid-ion Born–Mayer–Huggins–Fumi–Tosi (BMHFT) potential. Compared with the SM potential, the MD simulation with the BMHFT potential is highly successful in accurately reproducing the measured values of NaCl. At extended pressure and temperature ranges, the volume thermal expansion coefficient has also been predicted by the reliable BMHFT potential. The properties of NaCl in the pressure range 0–30 GPa at temperatures up to 1050 K are summarized.

Thermoelastic parameter αKT of sodium chloride at high pressure and high temperature

Two different potential models to the molecular dynamics (MD) simulations have been applied to investigate the thermoelastic parameter αKT of sodium chloride (NaCl) under high pressure and high temperature. The first one is the shell model (SM) potential that due to the short-range interaction when pairs of ions are moved together as is the case in that polarization of a crystal due to the motion of the positive and negative ions, and the second one is the two-body rigid-ion Born–Mayer–Huggins–Fumi–Tosi (BMHFT) potential with full treatment of long-range Coulomb forces. Particular attention is paid to the comparison of the SM- and BMHFT-MD simulations with the Debye model for the first time, and this model combines with ab initio calculations within local density approximation (LDA) and generalized gradient approximation (GGA) using ultrasoft pseudopotentials and a plane-wave basis in the framework of density functional theory (DFT), and it takes into account the phononic effects within the quasi-harmonic approximation. Note that the MD calculated volumes using SM model is somewhat larger than both the DFT and experimental volumes despite not considering the temperature effect. Compared with SM potential, the MD simulated 300K isotherm of NaCl with BMHFT potential is very successful in reproducing accurately the measured volumes and the GGA calculated volumes. Generally, it is found that there exist minor differences between the LDA and GGA computed the thermoelastic parameter αKT of NaCl, with both average results giving good agreement with SM-MD simulations. At an extended pressure and temperature ranges, the variation of thermoelastic parameter αKT which play a central role in the formulation of approximate equations of state has also been predicted. The properties of NaCl are summarized in the pressure range of 0–300kbar and the temperature up to 2000K.

Isothermal bulk modulus and its first pressure derivative of NaCl at high pressure and high temperature

The isothermal bulk modulus and its first pressure derivative of NaCl are investigated using the classical molecular dynamics method and the quasi-harmonic Debye model. To ensure faithful molecular dynamics simulations, two types of potentials, the shell-model (SM) potential and the two-body rigid-ion Born—Mayer—Huggins—Fumi-Tosi (BMHFT) potential, are fully tested. Compared with the SM potential based simulation, the molecular dynamics simulation with the BMHFT potential is very successful in reproducing accurately the measured bulk modulus of NaCl. Particular attention is paid to the prediction of the isothermal bulk modulus and its first pressure derivative using the reliable potential and to the comparison of the SM and the BMHFT potentials based molecular dynamics simulations with the quasi-harmonic Debye model. The properties of NaCl in the pressure range of 0–30 GPa at temperatures up to the melting temperature of 1050 K are investigated.

ChemInform Abstract: Structure and Properties of NaCl and the Suzuki Phase Na6CdCl8

ChemInform Abstract: Structure and Properties of NaCl and the Suzuki Phase Na6CdCl8

Comparative investigations of the P– V– T relationship of NaCl at high pressure and temperature

Two different potential models of molecular dynamics (MD) simulations have been applied to investigate the pressure–volume–temperature ( P– V– T) relationship and lattice parameter of NaCl under high pressure and temperature. The first one is the shell model (SM) potentials in which due to the short-range interaction pairs of ions are moved together as is the case in polarization of a crystal due to the motion of the positive and negative ions, and the second one is the two-body rigid-ion Born–Mayer–Huggins–Fumi–Tosi (BMHFT) potentials with full treatment of long-range Coulomb forces. The P– V relationship at 300 K, T– V relationship at zero pressure, and lattice parameter a, have been obtained and compared with the available experimental data and other theoretical results. Compared with SM potentials, the MD simulation with BMHFT potentials is very successful in reproducing accurately the measured volumes of NaCl. At an extended pressure and temperature ranges, P– V relationship under different isotherms at selected temperatures, T– V relationship under different pressures, and lattice parameter a have also been predicted. The properties of NaCl are summarized in the pressure range 0–30 GPa and the temperature up to 2000 K.

THERMAL CONDUCTIVITY OF SOLIDS AT HIGH TEMPERATURES AND HIGH PRESSURES

In the present study, we have extended the model due to Tang1based on the thermal conductivity equation due to Leibfried and Schlomann12so as to make it applicable for a wide range of pressures and temperatures. We have used the Stacey14,15equations of state (EOS) for determining the thermoelastic properties of NaCl , KCl and Al2O3at high pressures and high temperatures. These are used to estimate the variations of thermal conductivity with the change in pressure along different isotherms at selected temperatures. The results thus obtained are compared with the values derived from relations, which reproduced available experimental data well at low temperatures and low pressures. Experimental data at high temperatures and high pressures are not available. A close agreement between the two sets of data reveals the validity of the present work.

Elastic constants for NaCl and KCl solids at high temperatures

In the present study we derive new relationships to predict the temperature dependence of elastic constants. Proposed relationships are applied to study elastic constants of NaCl and KCl. A linear relationship between thermal expansivity and elastic constants at high temperatures is found to exhibit for solids. The extrapolated data on elastic constants in very high temperature region obtained in the present study are useful to understand the thermoelastic properties of NaCl and KCl. A close agreement between theory and experiment reveals the validity of the formulations used.

Low compression thermodynamic and thermoelastic properties of NaCl at high temperatures

In the present communication we have re-parametrized the thermodynamic and thermoelastic properties of NaCl at low compressions and high temperatures. It is found that the thermal expansivity and isothermal bulk modulus both change linearly with the increase in temperature at compressions down to 0.90. The present study reveals that the thermal pressure is nearly independent of compression along an isotherm. This is consistent with the earlier findings.

OSMOTIC POTENTIAL PROPERTIES OF SOLUTES COMMON IN THE SOIL-PLANT SOLUTION CONTINUUM

In this article, we report on the osmotic potential properties of NaCl, KCl, NH 4 Cl, CaCl 2 , NaNO 3, and MgSO 4 , common to soil solutions, and sucrose, D-fructose, and D-mannitol, found in plant solutions. The osmotic potentials of the solute solutions were calculated as the sum of three components: that due to the spacing difference of the free solution water molecules in the theoretical absence of solutes as compared with pure water, the loss of potential of the free solution water to keep solutes in solution, and its loss of potential to keep water firmly held to the solute particles in solution. These factors varied significantly between solutes. At the wilting level of plants, the spacing effect on the free solution water of the plant solution organic solutes ranged from 61 to 82% of their total osmotic potentials. This was only 41 to 49% for the soil solution inorganic solutes, due mainly to the loss of potential to keep water firmly held to ions in solution. The calculations indicate that the water-holding characteristics of soil solution ions would influence absorption by plants. The lesser amounts of water held to the organic solutes suggests that solution flow in the sieve tubes of the phloem is largely a function of the change in the spacing of the free water molecules of the solution. The analysis provides a new insight to solution flow through the soil-plant continuum.

Predictive Equations for Dielectric Properties of NaCl, D‐sorbitol and Sucrose Solutions and Surimi at 2450 MHz

ABSTRACT: Variation in dielectric properties of aqueous solutions with different concentrations and ratios of NaCl, D‐sorbitol, and sucrose were investigated at 21 °C using the open‐ended coaxial probe technique at 2450 MHz. Several equations to estimate dielectric properties of mixed or pure solutions were formulated. The equations were tested with other concentrations of solutions and surimi as a food sample containing the solutes. The correlation between the new measured dielectric properties and the calculated values were analyzed using a General Linear Model. The resultant prediction equations are suitable for pure and mixed aqueous solutions of (0 to 6%) NaCl, (0 to 18%) D‐sorbitol and (0 to 60%) sucrose. For surimi, only loss factor was successfully predicted.

High-temperature precipitation in NaCl: Eu2+ crystals

The influence of high-temperature annealing upon the mechanical and optical properties of NaCl: Eu2+ crystals was investigated. The new optical absorption band in the UV-range and softening of the matrix have been ascribed to the presence of EuCl2 particles with the structure of PbCl2.

Construction of a Thermally Stimulated Luminescence Reader for the Determination of Luminescence Properties of NaCl:Tl+

Thermally stimulated luminescence (TSL) glow curves induced by UV and visible radiation in NaCl:Tl + were measured by using a locally developed reader with spectral resolution, and analysed in order to determine the activation energies, frequency factors and kinetic orders. Additionally, TL emission spectra were obtained, and optical absorption, excitation and emission spectra were measured. With this information, peaks of TL emission spectra at 305 and 390 nm were associated with thallium dimers; others at 270, 450 and 530 nm were attributed to NaCl.

Sodium appetite in the sham-drinking rat after chorda tympani nerve transection.

Sodium depletion in the neurologically intact rat (Intact) produces a prompt and robust intake of NaCl. After chorda tympani nerve transection (CTX), there is a longer latency and a reduced intake of NaCl. The CTX rat depends on remaining gustatory and postingestive information to direct NaCl intake. In the present study, the effect of the removal of the postingestive signals of ingested NaCl (by means of a chronic gastric fistula) on the NaCl intakes and licking patterns of Intact and CTX rats was studied. When the gastric fistula was open (Sham), ingested NaCl did not pass beyond the stomach, thus negative postingestive stimulation was absent. After overnight sodium depletion, when postingestive stimulation was present (i.e., gastric fistula closed; Real), the CTX group drank significantly less 0.3 M NaCl than the Intact group over the 2-h test [11.7 +/- 1.6 (CTX) vs. 15.3 +/- 2.8 (Intact) ml]. In contrast, when postingestive signals were absent (i.e., Sham) the Intact group ingested 52.5 +/- 4.4 ml, whereas the CTX group had ingested only 12.4 +/- 3.1 ml of 0.3 M NaCl. Lickometer data analysis revealed that even during the first minute of the test the CTX/Real group generated significantly fewer licks than any of the other groups. Thus, although the CTX group was sensitive to inhibitory postingestive signals in the early portion of the appetite test, the absence of these signals did not release the robust and sustained intake of NaCl characteristic of the Intact group. These results suggest that information provided by the chorda tympani nerve is critically important to the strong motivational properties of NaCl after sodium depletion.

Thermal properties of NaCl and CsCl crystals under high pressure

A new interionic potential has been used to study the variation of heat capacity at constant volume, heat capacity at constant pressure and coefficient of volume expansion with pressure at room temperature. A classical theory of lattice vibrations, originally proposed for crystals under zero pressure, has been extended to calculate these thermal properties at higher pressures. These calculated values have been compared with the theoretical estimates obtained using a deformable dipole model of ionic solids. Values of heat capacity at constant volume have also been compared with experimental values.

Investigations of Defect Centres in Alkali Halides Doped with Trivalent Cations. Part 1: Bismuth in NaCl, KCl and RbCl Crystals

A correlated set of experiments was performed with a view to study the effect of trivalent bismuth upon some properties of NaCl, KCI and RbCI crystals. For NaCI the effect of BiO+ ions was also investigated. It was stated that: 1. The hydrolytic properties of bismuth are responsible for the formation of BiO+ centres also in crystals doped with BP+ ions. 2. During all experiments performed, the dopant remains in the form of trivalent cations. 3. Optical absorption spectra of bismuth are similar to those characteristic of other heavy metal ions with the s 2 electronic configuration. 4. The charge excess of BP+ ions is compensated by cation vacancies whereas for BiO+ ions the preferential bonding between Iii and O 2— serves for the charge compensation.

Influence of γ-irradiation on some properties of NaCl:Eu2+-Crystals. Part I: Correlated studies of optical and dielectric behavior

Abstract Room-temperature radiation-induced changes of the optical and dielectric characteristics of NaCl:Eu2+-crystals were investigated as a function of the concentration and dispersion state of the dopant. For nonirradiated crystals four types of Eu+2-spectra have been identified and ascribed to I.V. dipoles and various types of europium-related phases stable in the well-aged crystals.