Values Of Molar Volume Research Articles

Studies on the Shielding Properties of Transparent Glasses Prepared from Rice Husk Silica

The glasses studied here have been prepared by the melt quenching technique from Egyptian rice husk silica.The obtained solid glasses exhibit amorphous nature and transparency. These glasses were selected to obey the following composition, (75-x) mol % RH silica. 25mol % Na2O. x mol % Bi2O3, where x takes the values, 0, 5, 10, 15 and 20. It was found that, as Bi2O3 was gradually increased both the density and molar volume values increased. The comparison between the experimental and empirical density and molar volume values confirm that all the studied glasses are in amorphous glassy phase. Moreover, all samples showed also good shielding properties against gamma ray radiation and neutrons. The mass attenuation coefficient of gamma ray radiation increased gradually as Bi2O3 was gradually increased while the HVL values exhibit gradual decrease, and the sample that contains 20 mol % Bi2O3 appeared the efficient one at low gamma ray energy (especially at 356 KeV). On the other hand for shielding neutrons the sample that contains 5 mol% Bi2O3 appeared the best one since it exhibits the highest neutron removal cross section.

Densities and viscosities of binary mixtures of 2-methoxy-2-methylpropane with n-octane

Densities and viscosities of the binary system 2-Methoxy-2-methylpropane with n-octane have been measured at 293.15, 298.15, 303.15, and 308.15 K and atmospheric pressure, over the whole composition range. The excess values of molar volume, excess viscosity, and excess Gibbs free energy of activation of viscous flow were calculated from experimental measurements. Based on the variation of the excess functions with composition, conclusions about the molecular interactions in these kinds of mixtures were obtained. Emmerling et al., Jouyban–Acree, and Gonzales–Olmos–Iglesias models were used to correlate the density of these binary mixtures. Heric–Brewer, McAllister, Jouyban–Acree, and Herráez models have been used to calculate viscosity coefficients and these were compared with experimental data for the mixtures.

Volumetric and Viscometric Study of Binary Systems of Ethyl Butyrate with Alcohols

The density, viscosity, and refractive index of binary mixtures consisting of ethyl-butyrate + 1-propanol, 2-methyl-1-propanol, 1-butanol, 3-methyl-1-butanol, or 1-hexanol have been measured at atmospheric pressure and over the temperature range from (288.15 to 323.15) K. Excess and deviation functions have been calculated from these data and fitted to the Redlich–Kister equation. The values of excess molar volume and deviation functions were further used in the analysis of molecular interactions present in the mixture as well as the temperature influence on them.

The solid–liquid equilibrium, excess molar volume and refractive deviation properties of binary systems containing dimethyl carbonate, anisole and phenol

The solid–liquid equilibrium (SLE), excess molar volume and refractivity deviation values were reported for binary systems consisting of dimethyl carbonate (DMC), anisole and phenol, all three of which are reaction intermediates in the synthesis of polycarbonate (PC). The SLE plots for the binary systems {DMC+anisole}, {DMC+phenol}, {anisole+phenol} at atmospheric pressure displayed a single eutectic point and correlated well with the values calculated using the non-random two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) equations. The excess molar volume (VE) and the deviation in the molar refractivity (ΔR) were calculated using density and refractivity data measured at 323.15K. The calculated VE and ΔR data deviated from ideal behavior in either a negative or a positive direction, depending on the particular binary system. The experimental data correlated well with the curves calculated using the Redlich–Kister equation.

Volumetric, acoustic and IR spectroscopic investigation of molecular interactions in selected binary liquid mixtures of N-methyl-2-pyrrolidone and alkylamines over the temperature range 303.15–318.15 K

The densities and speeds of sound for pure liquids N-methyl-2-pyrrolidone (NMP), propylamine (PA), butylamine (BA), dipropylamine (DPA) and their binary mixtures containing NMP as a common component have been measured at atmospheric pressure as a function of composition of NMP in the temperature range of 303.15–318.15K. From the experimental data excess values of molar volume, isentropic compressibility and ultrasonic speed are computed and fitted to a Redlich–Kister type equation. An attempt is made to use FT-IR spectral analysis of these binary mixtures to understand the interactions present and to correlate them with thermodynamic findings. Further, the ultrasonic speeds have been evaluated by using various theoretical models viz. Nomoto, Van Dael-Vangeel ideal mixing, impedance dependence, Rao's specific velocity method, Junjie's relations, Jacobson's free length theory (FLT) and Schaaff's collision factor theory (CFT). Chi-square test for the goodness of the fit is applied to investigate the relative applicability of these theories to the present systems.

Study of Solvent and Temperature Effects on Volumetric, Viscometric and Conductometric Studies of Amlodipine Besylate

Volumetric, viscometric and conductometric studies of 0.8 x 10-3 to 8 x 10-3 mol/Kg solutions of amlodipine besylate in distilled water and methanol were done at temperature range of 293.15, 298.15, 303.15, 308.15, 313.15, 318.5 and 323.15 K. from the determined values of density apparent molar volume ( ) and viscosity (η) were evaluated. Density data was analyzed and discussed using Masson empirical relationship and that of viscosity to Jones-Dole equation to evaluate partial molar volume ( ), intrinsic co-efficient SV, viscosity A and B parameters. All parameters were discussed as a function of concentration and temperature. For all set of dilutions conductometric studies in both solvents of study were employed. Obtained data was analyzed to judge the ion-ion and ion-solvent interactions. Structure making and breaking aspects of amlodipine besylate in polar solvents were discussed. These all parameters were studied to disclose the mechanism of action of drug and its transportation across biological membranes. Keywords: Apparent molar volume; partial molar

Crystallization kinetic of Sb–V2O5–TeO2 glasses investigated by DSC and their elastic moduli and Poisson’s ratio

Ternary tellurate glasses of the form xSb–(60−x)V2O5–40TeO2 (0≤x≤15 in mol%) were prepared by using the usual melt quenching method. Differential scanning calorimetry (DSC) at different heating rates (φ) was used to thermal analyze and to gain more insight in to the thermal stability, glass forming tendency and so calorimetric behavior of the present glasses. The glass transition temperature (Tg), the temperature corresponding to the onset of crystallization (Tx) and also the crystallization temperature (TCr) were obtained at different heating rates, to estimate the key kinetic parameter of activation energy of crystallization (ΔE) by using different empirical formulas. Also some other thermal parameters such as thermal stability and glass forming tendency were determined. It was found that Tg, Tx and TCr increase with increase in Sb content and also with increase in heating rate. Moreover, Makishima–Makenzie’s theory was employed to evaluate the Poisson’s ratio and elastic moduli, indicating a strong relation between elastic properties and the structure of glass. From the mechanical and thermal data and also the values of oxygen molar volume (VO⁎), it was founded that the glass systems can be divided in to “two compositional regions”; so, results indicate that glasses with 10≤x≤15 (especially for x=12) are more thermal stable and strong glasses, which make them as more useful and promising materials in technological advantages and device manufacturing.

Luminescence efficiency growth in wide band gap semiconducting Bi2O3 doped Cd0.4Pb0.1B0.5 glasses and effect of γ-irradiation

Cadmium lead borate glasses together with other glasses containing different Bi2O3-doping concentrations (2.5, 5, 7.5, 10mol%) were prepared by conventional melt annealing method. The density and molar volume values were calculated to obtain some insight on the packing density and arrangement in the network. Also their optical and structural properties have been characterized by means of X-ray diffraction, UV–visible spectroscopy, luminescence spectroscopy and FTIR spectroscopy. Optical measurements have been used to determine the optical band gap (Eg), Urbach energy (ΔE) and the refractive index (n). The results demonstrate the effective rule of Bi2O3 on the studied glasses. The undoped and Bi2O3 doped – glass show strong extended UV-near visible absorption bands which are attributed to the collective presence of both trace iron impurities from raw materials and also the sharing of bismuth Bi+3 ions. Furthermore, the luminescence intensity strongly increases with increasing Bi2O3 content which may be attributed to transfer of energy from transitions in its energy levels. It has been revealed that the decreasing values of optical band gap and band tail can be understood and related in terms of the structural changes that are taking place in the glass samples. The infrared absorption spectra of the prepared glasses show characteristic absorption bands related to the borate network (BO3, BO4 groups) together with vibrational modes due to Bi–O groups upon the introduction of Bi2O3. The prepared samples reveal a very limited response towards of gamma irradiation which reflects its shielding behavior towards the effect of such type of irradiation.

Measurements of the density and viscosity of 1-hexene+1-octene mixtures at high temperatures and high pressures

The density and viscosity of binary 1-hexene + 1-octene mixtures have been simultaneously measured over the temperature range from (298 to 470) K and at pressures up to 196 MPa using a hydrostatic weighing and falling-body techniques, respectively. The measurements were made for three concentrations of 0.200, 0.429, and 0.692 mole fraction of 1-octene. The combined expanded uncertainty of the density, pressure, temperature, and viscosity measurements at the 95% confidence level with a coverage factor of k = 2 is estimated to be (0.15–0.30) %, 0.05%, 0.02 K, and (1.5–2.0) %, respectively, depending on temperature and pressure ranges. The measured densities and viscosities were used to calculate the excess molar volumes and viscosity differences. It is shown that the values of excess molar volume for 1-hexene + 1-octene mixtures are negative, while the viscosity differences are mostly positive at all measured temperatures and pressures over the whole concentration range. The measured densities and viscosities were also used to develop a Tait-type equation of state and viscosity correlation model for liquid 1-hexene + 1-octene mixtures. Theoretically based Arrhenius-Andrade and Grunberg and Nisan type equations were used to represent the temperature and concentration dependences of the measured viscosities for liquid 1-hexene + 1-octene binary mixtures at atmospheric pressure.

Molecular interactions in binary mixtures of 1-butoxy-2-propanol with alcohols at different temperatures: A thermophysical and spectroscopic approach

This paper reports densities (ρ) and speeds of sound (u) of 1-butoxy-2-propanol CH3(CH2)3OC3H6OH, 1-propanol CH3(CH2)2OH, 2-propanol (CH3)2CHOH, 1-butanol CH3(CH2)3OH and 2-butanol CH3CH2CH(OH)CH3 and their binary mixtures with 1-butoxy-2-propanol as a common component, measured at T=(293.15, 298.15, 303.15, 308.15 and 313.15)K over the entire composition range. These experimental values of density and speed of sound were used to calculate the values of excess molar volumes, VmE, deviations in molar isentropic compressibility Δκs and deviations in speed of sound uD. Further, experimental densities were used to estimate apparent molar volumes Vϕ,i, partial molar volumes V‾m,1, excess partial molar volumes V‾m,1E and their limiting values at infinite dilution Vϕ,i∞, V‾m,i∞ and V‾m,iE,∞ respectively. The variations observed in these properties, with composition and temperature, are discussed in terms of molecular interactions due to physical and chemical effects between the unlike molecules of the binary mixtures. These properties, especially excess functions, are found to be quite sensitive towards the intermolecular interactions in liquid mixtures. These excess functions and deviations have also been correlated using Redlich–Kister type polynomial equation by the method of least-squares for the estimation of the binary coefficients and the standard errors. FT-IR studies of these mixtures are also reported.

Optical Absorption and Photoluminescence Properties of Dy<sup>3+</sup> Ions in Bi<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub>-B<sub>2</sub>O<sub>3</sub> Glass System

This research studied the effect of dysprosium on the physical, optical and luminescence properties of the bismuth borosilicate glass in compositions 40Bi2O3 : 20SiO2 : (40-x)B2O3 : xDy2O3 (where x = 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mol%). The glass systems have been prepared at 1100 °C by melt quenching technique. The results showed that the density and molar volume of glass samples are between 4.6477 ± 0.0020 to 5.0047 ± 0.0041 g/cm3 and 45.6608 to 48.6797 cm3/mol, respectively. The values of density and molar volume of these glasses were not depend on the Dy2O3 concentration. The optical absorption spectra of glass samples in the UV-Vis-NIR region shows absorption bands at 794, 906, 1094, 1276 and 1690 nm, respectively. The photoluminescence spectra show emission bands at 482 (blue), 576 (green), 663 (yellow) and 756 (red) nm under 453 nm excitation wavelength. The emission spectrum at 576 nm has shown a strongest intensity.

Micellization properties and related thermodynamic parameters of aqueous sodium dodecyl sulfate and sodium dodecyl sulfonate solutions in the presence of 1-propanol

Effects of 1-propanol (1P) addition on the micellar and thermodynamic parameters of aqueous solutions of anionic surfactants sodium dodecyl sulfate (SDS) and sodium dodecyl sulfonate (SDSn) was investigated by experimentally measured electrical conductivities, densities and sound velocities at 298.15K. The values of the critical micelle concentration (CMC) of both surfactants in the investigated mixed aquo-1P solvents (wt% 1P 2.5, 5, 7.5 and 10) are smaller than those in pure water and the CMC decreases with increasing 1P concentration in solution to a minimum at (w/w) % 1P=5 and then increases. However the values of the counterion condensation on the micelle decrease with an increment in the amount of 1P. Furthermore the values of the apparent molar volume and isentropic compressibility of the monomeric and micellar forms of the investigated surfactants were obtained from the experimental density and sound velocity data. It was found that, although the values of the apparent molar properties of micellar form of surfactants increase by increasing the organic solvent content, the values of the apparent molar volume of the monomeric form of the surfactants decrease with increasing concentration of 1P.

Choice of the center of water molecules in calculations of partial molar volume of single ions immersed in water: A molecular simulation study

In the Kirkwood–Buff theory, the center of each solvent molecule can be arbitrarily chosen. However, this arbitrariness is not obvious in the calculation of the Kirkwood–Buff integral for a single ion. Actually, the Kirkwood–Buff integral depends on the choice of the center of a solvent molecule, if each solvent molecule has a dipole moment and the solute has a net charge. A few examples based on molecular dynamics simulations are shown. A surrogate definition for the center of a water molecule is also shown. A good agreement between the calculated and experimental values of partial molar volumes for single ions is observed.

Iron modified structural and optical spectral properties of bismuth silicate glasses

Iron bismuth silicate glasses have been successfully synthesized by melt quenching technique. The amorphous nature of the glass samples is ascertained by the XRD patterns. The values of density, molar volume and crystalline volume have been measured and are found to decrease with increase in iron content. The glass transition temperature measured using Differential Scanning Calorimetry (DSC) also varies with increase in Fe2O3 content. The Raman and FTIR spectra of the studied glass system taken at room temperature suggests that Fe2O3 modifies the structure of bismuth silicate glasses and it acts as both network modifier as well as network former. Bismuth also plays the role of both network modifier (BiO6 octahedra) as well as network former (BiO3 pyramids) and SiO2 exists in SiO4 tetrahedral structural units with two non-bridging oxygens. The Hydrogenic excitonic model is found to be applicable to the studied glass compositions. The variation in Urbach energy value observed for the studied glass samples suggests the possibility of increase in the number of glass defects. The metallization criterion for the synthesized glass samples is determined and found to be in the range 0.30–0.38.

Experimental study of the density and derived (excess, apparent, and partial molar volumes) properties of binary water + ethanol and ternary water + ethanol + lithium nitrate mixtures at temperatures from 298 K to 448 K and pressures up to 40 MPa

Densities of binary water+ethanol and ternary water+ethanol+LiNO3 mixtures have been measured over the temperature range from 298K to 448K and at pressures up to 40MPa using the constant-volume piezometer immersed in a precision liquid thermostat. The measurements for water+ethanol mixture were made for four compositions of 0.0163, 0.0343, 0.0730, and 0.0946mol fraction of ethanol. The measurements for thernary water+ethanol+LiNO3 mixtures were performed in the same temperature and pressure ranges for twelve concentrations. The combined expanded uncertainty of the density, pressure, temperature, and concentration measurements at the 95% confidence level with a coverage factor of k=2 is estimated to be 0.06%, 0.05%, 20mK, and 0.015%, respectively. The derived volumetric properties such as excess (VmE), apparent (VΦ), and partial (V¯2∞) molar volumes were calculated using the measured values of density for the binary water+ethanol mixture and for pure water and ethanol. The small and negative values of excess molar volume for the mixtures were found at all experimental temperatures, pressures, and over the entire concentration range. The excess molar volume minimum is found at concentration about 0.4mol fraction of 1-propanol. The concentration minimum of the derived apparent molar volumes VΦ near 2molkg−1 (dilute mixture) was observed.

Volumetric and Surface Properties of Aqueous 1-Alkyl-3-methylimidazolium Propionate {[Cnmim][Pro] (n = 4, 5, 6)} Ionic Liquids at 298.15 K

Three propionic acid ionic liquids (PrAILs), 1-alkyl-3-methylimidazolium propionate ([Cnmim][Pro] (n = 4, 5, 6)), were prepared by the neutralization method and characterized by 1H NMR spectroscopy. The values of the densities and surface tensions of aqueous [C4mim][Pro], [C5mim][Pro], and [C6mim][Pro] with various molalities were determined at 298 K, and the values of the parachor for these solutions were calculated. The values of the apparent molar volumes and partial molar volumes at infinite dilution for the ILs were estimated in terms of Pitzer’s theory. With the use of Li’s model of surface tension and the empirical equation of the parachor, the values of the surface tensions of these aqueous solutions for three PrAILs were estimated and the estimated values were in good agreement with experimental ones.

Simultaneous measurements of the density and viscosity of 1-hexene + 1-decene mixtures at high temperatures and high pressures

The density and viscosity of binary 1-hexene+1-decene mixtures have been simultaneously measured over the temperature range from 298 to 470K and at pressures up to 196MPa using hydrostatic weighing and falling-body techniques, respectively. The measurements were made for three concentrations of 0.25, 0.50, and 0.75 mass fraction of 1-decene. The combined expanded uncertainty of the density, pressure, temperature, and viscosity measurements at the 95% confidence level with a coverage factor of k=2 is estimated to be 0.15 to 0.30%, 0.05%, 0.02K, and 1.5 to 2.0%, respectively, depending on temperature and pressure ranges. The measured densities and viscosities were used to calculate excess molar volumes and viscosity differences. It is shown that the values of excess molar volume for 1-hexene+1-decene mixtures are positive, while the viscosity differences are negative at all measured temperatures and pressures over the whole concentration range. The measured densities and viscosities were also used to develop a Tait-type equation of state and viscosity correlation model for liquid 1-hexene+1-decene mixtures. Theoretically based Arrhenius–Andrade type equations with concentration dependent coefficients were used to represent the temperature and concentration dependences of the measured viscosities for liquid 1-hexene+1-decene binary mixtures at atmospheric pressure.

Densities, speeds of sound, viscosities and FT-IR spectroscopic studies of binary mixtures of 1-tert-butoxy-2-propanol with alcohols (C6, C8, C10) at different temperatures

This article presents densities, ρ and speeds of sound, u of 1-tert-butoxy-2-propanol (CH3)3COCH2CH(OH)CH3 with alcohols, viz., 1-hexanol CH3(CH2)5OH, 1-octanol CH3(CH2)7OH and 1-decanol CH3(CH2)9OH at 293.15, 298.15, 303.15, 308.15 and 313.15K and viscosities, η at 298.15, 303.15 and 308.15K over the entire composition range. These experimental data of density and speed of sound were used to calculate the values of excess molar volumes, VmE, excess molar isentropic compressibilities, KS,mE, and deviation in speeds of sound, uD. Viscosity data was used to compute deviation in viscosities, ∆η. The viscosity data have been correlated with the equations of Heric and Brewer (three-parameter), and McAllister (four body interactions). The calculated excess properties are discussed in terms of molecular interaction between present investigated binary mixtures and with Fourier Transform infrared (FT-IR) spectroscopy. These excess functions and their deviations have also been correlated using Redlich–Kister type polynomial equation by the method of least-squares for the estimation of the binary coefficients and the standard errors.

Determination of Volume Properties of Aqueous Vanadyl Sulfate at 283.15 to 323.15 K

This paper reports the densities of aqueous VOSO4 that were measured by an Anton Paar DMA 4500 M from 0.0500 mol·kg–1 to 3.000 mol·kg–1 at 283.15 to 323.15 K. The apparent molar volume, ϕVB, the partial molar volume of VOSO4, V̅B, the apparent molar expansibility of the solute, ϕE, and coefficient of thermal expansion of the solution, α, were calculated. First, these properties described above have been discussed with the temperature and concentration variation. Then the values of the apparent molar volume, ϕVB, were fitted to Pitzer’s model for volumetric properties by the method of the least squares, which allowed the partial molar volume of the VOSO4 at infinite dilution, V̅B0, and Pitzer’s parameters, βMX(0)V, βMX(1)V, and CMXV, to be obtained. The small standard deviations of the fitting show that Pitzer’s model is also appropriate for representing the volumetric properties of aqueous solutions of VOSO4. Using the data from literature, the partial molar volume of the ion VO2+ at infinite dilution, V̅C0, was discussed and the result showed that the negative value of V̅C0 can be attributed to strong hydration of VO2+ as other divalent ions.

Characterization of copper doped phosphate glasses for optical applications

The phosphate glass system of chemical composition 42P2O542ZnO(16−x)Na2O(x)Cu2O with (x=0, 2, 4, 6, and 8) has been prepared by the conventional glass melt technique. The effect of copper content on density and molar volume has been investigated. It was found that the density of the glass increases with increasing copper content. This can be accounted by the difference between the atomic weights of copper and sodium. The estimated values of molar volume follow the common pattern where it exhibits opposite trend to that of density. The optical absorption has been measured from 200 to 900nm. While absorption is observed only in the UV range for the base glass, a well defined absorption band has been observed in the visible region, the width of which increases by increasing copper content. With higher copper content another band starts to appear in the IR range. The refractive index has been estimated according to the Clausius–Mossotti method using the ionic refraction. The obtained values of refractive index have been used in estimating some characteristic features such as elasto-optic coefficient and susceptibility. The results reveal the importance of such glass composition in optical filter applications.