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Melt quenching technique has been used to fabricate calcium boro-phosphate glasses doped with praseodymium oxide ions. With increased P 2 O 5 content, structural parameters like oxygen molar volume (Vo) and oxygen packing density (OPD) indicate an opposing trend. In addition to optical factors like optical electronegativity, absorption edge, and direct and indirect bandgap values being estimated and discussed, optical absorption spectra have been recorded for all the glasses. The presence of ionic bond behaviour confirms the strong structural and optical property changes caused by the P 2 O 5 content. Using the Phy-X software application, the radiation shielding parameters were investigated. The incorporation of B 2 O 3 , CaCO 3 , and P 2 O 5 offers more number of bridging oxygens which further leads to closely packed nature. Considering the glass sample B0PCM:Pr, the highest linear attenuation coefficient (LAC) is determined. The LAC results showed that at high energy levels, the glass's shielding performance became more consistent. The results of the effective atomic number analysis demonstrated the impact that CaCO 3 has on the glass's shielding effectiveness, with a higher concentration of CaCO 3 improving the material's defence against gamma radiation. For B0PCM:Pr glass, the half value layer (HVL) rises from 2.101 to 3.444 cm at 0.284–1.333 MeV. Certainly, it has been observed that the glass tends to have a smaller HVL when it contains more CaCO 3 with lesser P 2 O 5 content. • Lead free calcium boro-phosphate glasses have been synthesized via melt quench method for radiation resisting applications. • Physical, structural, elastic and optical properties of all the prepared glasses were examined in detail. • B0PCM:Pr exhibits higher LAC and confirms the consistent performance of the prepared glasses at higher energy levels. • The Z eff confirms that the steady increase of CaCO 3 increases the shielding efficiency of the prepared lead free glasses. • The HVL increases from 2.10 to 3.44 cm between 0.284 and 1.33 MeV for B0PCM:Pr glass. [ABSTRACT FROM AUTHOR]

Dy3+ doped boro-phosphate glasses [BPXNfDy 1.0 ] were synthesized with the chemical composition 44B 2 O 3 +25P 2 O 5 +15NaF+15MO+1Dy 2 O 3 (where M=Li 2 CO 3 , Mg 2 CO 3 , Sr 2 CO 3 , ZnO and Ba 2 CO 3) by conventional melt-quenching method. The physical properties (density, refractive index), structural (boron-boron separation, phosphorous-phosphorous separation), FTIR (functional groups) and absorption properties (direct and indirect bandgap) were explored in examining the ability of the proposed multicomponent glasses for radiation protection applications. The XRD pattern declared the non-periodicity/amorphous nature of the sample. The Ba-containing glass is observed to possess a tightly packed nature among the present glass samples, which is confirmed from the evaluation of the structural parameters such as d B−B , d P−P. The molar volume (V m), and oxygen packing density (OPD) of the Ba-incorporated glass possess reversal behavior. Similarly, Mg-included glass exhibits an inverse trend for Poisson's ratio and fractal bond connectivity parameters. Furthermore, the evaluation of optical features like bandgap energy was achieved from the absorption analysis. The formation of bridging oxygens is observed to be in accordance with oxygen packing density values. [ABSTRACT FROM AUTHOR]

The high-pressure behavior of the alkali metals has attracted much attention in both experimental and theoretical aspects. This study is focused on the thermodynamic optimization of the temperature and pressure dependence of the molar volumes, the compressibility and phase diagrams of Li, Na and K according to the CALPHAD method. The pressure-temperature phase diagrams of lithium, sodium and potassium up to 50–100 GPa were calculated using the obtained thermodynamic parameters. The available experimental data, such as extremely low melting temperatures at high pressure, pressure-induced structural transitions between simple bcc and fcc crystals and the molar volume changes with the increasing pressure, were well reproduced in our calculations. The good agreements between our calculations and the experiments assessed in the literature indicated that our thermodynamic parameters are reasonable. Our thermodynamic calculations would assist to understand the phase transitions and structural properties of alkali metals at high pressure. [ABSTRACT FROM AUTHOR]

An experimental analysis comprising pongamia, soyabean, and corn biodiesel was selected and mixed with diesel and di-butyl ether at different proportions for its viability and phase separation. The test samples were experimentally confirmed for their density, sound speed, and refractive index characteristics by varying the temperatures between 298 K and 343 K. The mixing models, namely the Lorentz-Lorenz (L-L) and Gladstone-Dale (G-D) methods, were tested for the uncertainty of experimental results. The use of artificial neural networks (ANN) was made as an attempt to characterize the backpropagation algorithm's gradient to pursue the minimum error function of experimental and mixing models. The L-L and G-D with and without ANN equations were used to compare the different proportions and temperatures for the fuel blends of D50PD50, D50PD45DBE05, and D50PD25DBE25, and so on. Furthermore, each sample has been computed for the excess molar volume, and interactions between the liquids have been verified. The exergy analysis for PD, SB, and CB biodiesel under ambient conditions and the experimental and predicted results of energy destruction can be narrowed. The use of ternary fuel in place of diesel shows significant improvements in terms of energy annihilation and homogeneity, which have a lesser impact on emissions and the environment. [Display omitted] • Qualitative proportions endorse fuel parameters due to temperature influences. • Experimental and mixing model error analysis using the ANN backpropagation algorithm. • Hypothetical and attainable outcomes of ternary blends in energy and exergy analysis. • Exergy analysis provides substantial prospects for resolving environmental problems. [ABSTRACT FROM AUTHOR]

Ferrite-based slags are the basic systems in the pyrometallurgical production of copper, and the density and molar volume of these systems are of vital importance for optimizing the metallurgical process. However, due to the high melting points of melts and the expensive trial costs, experimental methods are inefficient to obtain all the data needed. As a result, a geometrical model has been applied to the estimation of density and molar volume of ferrite-based ternary slags. The calculated results agree well with experimental data in three ferrite-based ternary systems of Fe 2 O 3 –CaO–FeO, Fe 2 O 3 –BaO–FeO and Fe 2 O 3 –CaO–Cu 2 O. The mean deviation of the predicted results by the present model is lower than those by various empirical models for corresponding systems. The application of the present will enrich the data of density and molar volume for more ternary melts. [ABSTRACT FROM AUTHOR]

[Display omitted] • Molecular interactions between metformin hydrochloride in water and aqueous dulcitol were investigated. • The Volumetric, acoustic, conductance and UV–visible studies were used to interpret the various possible interactions. • Ion-hydrophilic and H-bonding interactions dominate over hydrophobic–hydrophobic interactions. • Metformin hydrochloride behaves as a structure maker in water and aqueous dulcitol systems. The interactions of a drug with the solvents render imperative information in respect of its behaviour and operation in various areas. The anti-diabetic drug metformin hydrochloride (MF) interacts with water and dulcitol in aqueous solutions, and these interactions have been studied through volumetric, ultrasonic, conductometric, and UV–visible methods. The density (ρ), sound velocity (u), and molar conductance (Λ m) of MF in water and aqueous dulcitol (2, 4, and 6 % w/v) have been recorded at four different temperatures to elucidate the interactions of MF with the solvents. The measured parameters were then interpreted in terms of partial molar volume (Φ v 0) using Masson's equation, adiabatic compressibility (β) using Newton- Laplace equation. In addition to this many other thermodynamic parameters including partial molar volumes of transfer (Δ tr ϕ v 0) , and Walden's product were also calculated. These parameters were interpreted to draw insight into MF-MF and MF-solvent interactions. Hepler's constant and Walden's temperature coefficient was utilized to determine the structure-making/breaking behaviour of MF in water and aqueous dulcitol solvent systems. In addition to this, spectroscopic analysis using UV–visible spectrophotometer has also been carried out to support the results obtained by various parameters. The rise in intensity and a shift in UV–visible absorption maxima with an increase in MF concentration in the studied solvent systems, suggests that MF interacts strongly with solvents. Moreover, the structure-making nature of MF in the studied solvent system of water and aqueous dulcitol was confirmed by Walden's product and Hepler's constant. [ABSTRACT FROM AUTHOR]

• The investigated properties were studied in the entire concentration range. • Volume contraction was identified in the investigated systems. • The MF-K2ZrF6 (MF = LiF, NaF, KF) systems were converted to the ZrF4 coordinate and compared with literature data. Critical evaluation of volume properties (based on density measurements using Archimedean method) of the zirconium-based fluorides melts MF-K 2 ZrF 6 (M = Li, Na, and K) revealed the different properties of KF system in contrast to LiF and NaF systems. Excess molar volume adopts negative values in the entire concentration range for all three investigated systems. Partial molar volumes of K 2 ZrF 6 were obtained by using two different approaches - simple polynomial regression analysis and multicomponent polynomial regression in the form of the Redlich-Kister equation. Finally, the excess partial molar volume of K 2 ZrF 6 in KF shows smaller overall volume contraction that adopts 60% of volume contraction in LiF or NaF systems. The obtained data of density, molar volumes and partial molar volumes were compared with accessible literate data after recalculation to the MF-ZrF 4 coordinates. [ABSTRACT FROM AUTHOR]

• High-temperature (200°C) and high-pressure (6.9 MPa) laboratory set-up to measure aqueous foam thermal stability by recording foam half-life. • Foam half-life decreased exponentially with increase in temperature. • Foam half-life increased with an increase in foam generation pressure, even at high temperature of 200°C. • Foam thermal stability is directly proportional to the activation energy of foam system. • Foam stability and drainage rate are strongly dependent on temperature, pressure, and gas composition. In Enhanced Geothermal System (EGS) hydraulic fracturing is carried out by injecting cold water into deep Hot Dry Rocks (HDR) under carefully controlled conditions to create new or reopen existing fractures. Water-based fracturing fluids demonstrate some challenges including immense quantity of water usage, water sensitivity of the formations, water blocking, and lack of proppant carrying capacity and transportation. Thus, an alternative is to use foam-based fracturing fluid which offers potential advantage over conventional water-based fracturing fluid such as minimum water usage, reduced wellbore damage, high proppant carrying capacity, and less environmental damage. However, foams are complex mixture of gaseous phase and liquid phase which are thermodynamically unstable at downhole conditions, and their stability can decrease over time due to liquid drainage, bubble coarsening, and coalescence. This paper shows laboratory experiments executed to study foam stability at high temperature (200 °C) and high pressure (6.9 MPa) conditions which simulates the geothermal environment. Foam stability was characterized by half-life of foam, which is defined as the time taken by the foam to decreases by 50% of its original height due to drainage. In this paper, two types of gaseous phases, nitrogen (N 2) and carbon dioxide (CO 2) were investigated. Also, based on successful practice of foam-based fracturing fluid in oil and gas industries, four surfactants, including Alpha olefin sulfonate (AOS), Sodium dodecyl sulfonate (SDS), Tergitol™ (NP – 40), and Cetyltrimethylammonium chloride (CTAC) at optimum concentration of 1 wt.% were tested for best stability performance. In addition, different stabilizing agents including guar gum, bentonite clay, crosslinker, silicon dioxide nanoparticles (SiO 2), graphene oxide (GO) were also studied. Experimental results showed that N 2 foams were more stable than CO 2 foams. It was observed that foam half-life decreased with the increase in temperature. Among all the surfactants, AOS foams showed the most promising thermal stability at high temperatures. Moreover, with the addition of stabilizing agents, foam's half-life was enhanced. Stabilizing agents such as crosslinker and GO dispersion showed the most stable foams with half-life recorded at 20 min and 17 min, respectively, at 200 °C and 6.9 MPa. Finally, pressure also showed a positive effect on foam stability; with increased pressure, foam half-life was increased. Based on the experimental data, analytical models for the effect of temperature and pressure were developed, considering foam degradation is a first-order kinetic reaction that linearly depends on the foam drainage mechanism. The effect of temperature on foam half-life was studied as an exponential decay model. In this model, foam half-life is a function of drainage rate constant (D A) and activation energy (E a) of the foam system. The effect of pressure on foam half-life was found to obey a power-law model where an increase in pressure showed an increase in foam half-life. Furthermore, a linear relation was studied for the effect of pressure on foam activation energy and drainage rate. Then the combined effects of temperature and pressure were studied, which yielded an analytical model to predict the foam stabilities in terms of half-life for different foam compositions. This research indicates that with an appropriate selection of surfactants and stabilizing agents, it is possible to obtain stable foams, which could replace conventional water fracturing fluid under EGS conditions. [ABSTRACT FROM AUTHOR]

We show that the molar volume of an alkali-alkaline earth-silicate glass system can be well understood through Voronoi polyhedra. A good agreement of the partial molar volumes of Na 2 O, K 2 O, MgO, CaO, and SiO 2 is achieved between molecular dynamics simulations using Voronoi analysis and experimental data. The physical meaning of the partial molar volume is illustrated considering the Voronoi volume contributions of both cations and oxygen atoms. Discrepancies between the linear model predictions and the measurements observed in both molecular simulations and experiments can be attributed to the Voronoi volume change of potassium due to its complex interaction with other species. Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract Transition metal oxide–doped glassy nanocomposites of the form x V 2 O 5 -(1 − x) (0.05CdO-0.95ZnO) with x = 0.3, 0.5, 0.7, and 0.9 were prepared by the melt quenching route. Their microstructure was studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy, transmission electron microscopy, and optical absorption spectroscopy. The absorption bands at around 640–756 cm−1 are attributed to the antisymmetric stretching vibrations of VO 2 groups. Physical attributes such as density, molar volume, oxygen molar volume, oxygen packing density, number of bonds per unit volume, and the average stretching force constant were evaluated. The XRD patterns reveal distinct diffraction peaks indicating crystallinity in the sample with x = 0.3, whereas significantly broadened patterns are observed in samples with x = 0.5, 0.7, and 0.9, reflecting a dominant amorphous nature. Different peaks in the XRD patterns indicate the formation of Zn 2 V 2 O 7 , ZnV 2 O 6 , CdV 2 O 6 , Cd 2 V 2 O 7 , and CdVO 3 nanocrystallites, which are dispersed in the as-prepared glassy matrices. The optical absorption spectra show indirect transitions. With a rise in the concentration of V 2 O 5 , the optical transmission cutoff wavelength moves to higher wavelength. DC electrical conductivity was studied at various temperatures from 60–650 °C. The establishment of small polaron hopping was anticipated from the DC electrical conductivity data. DC conductivity was inferred with use of Mott's and Greaves's variable range hopping models. Graphical abstract Image 1 Highlights • Density, molar volume, X-ray diffraction patterns and transmission electron microscopy of vanadate glassy systems. • DC conductivity. • Average bond dissociation energy. • Conduction mechanism, phonon-assisted electron or polaron hopping. • Formationof Zn 2 V 2 O 7 , ZnV 2 O 6 , CdV 2 O 6 , Cd 2 V 2 O 7 , and CdVO 3 nanocrystallites. [ABSTRACT FROM AUTHOR]

The sodium borate glasses doped with different CuO content (70B 2 O 3 ˗30Na 2 O˗xCuO with x = 0, 2, 4, 6 and 8 mol%) have been prepared using the conventional melt-quenching technique. The amorphous nature of the prepared samples has been identified by X-ray diffraction (XRD). The experimental and theoretical density, the molar volume, and the oxygen packing density have been defined. The effect of CuO incorporation into the 70B 2 O 3 ˗30Na 2 O glass base on the electrical and dielectric properties has been studied. The D.C. electrical parameters have been measured in the temperature range 323˗483 K, while the dielectric parameters have been measured in the temperature range 333˗483 K and the frequency range 10−1˗ 107 Hz. The D.C. electrical conductivity increases while the activation energy decreases by increasing CuO content (mol%). The conduction type is ionic which CuO inserts into the glass structure as a glass modifier. The A.C. study reveals that all investigated glasses obey the correlated barrier hopping model (CBH). Moreover, the dissipation factor peaks indicate the glasses' relaxation nature which has been further analyzed from the real and imaginary parts of the electric modulus. • The pure and CuO-doped sodium borate glasses have been prepared using the conventional melt-quenching technique. • The XRD analysis confirms the amorphous nature of the glasses. • The activation energy of the glass decreases with increasing CuO content (mol%) from 0.895 to 0.730 eV. • The A.C. studies demonstrate that the investigated glasses obey the correlated barrier hopping (CBH) model. • The presence of a peak in the frequency dependence of tan δ for all samples indicates the relaxation nature of these glasses. [ABSTRACT FROM AUTHOR]

Highlights • Measuring volumetric properties of non-aqueous system of (DEA + DMF). • To analyze the effect of temperature and concentration on the properties using RSM. • Significant effect of temperature and concentration on the properties. • Using JAM as accurate model to correlate the volumetric properties data. Abstract This paper reports the volumetric properties such as density, molar volume and isobaric thermal expansion of non-aqueous system of DMF-DEA. The values of volumetric properties were reported for several mole fractions of DMF (x 1) and DEA (x 2) and temperature from 298.15 to 343.15 K. In order to investigate the significance of temperature and concentration on the each volumetric property and develop regression models, a user-defined method of response surface methodology (RSM) was applied. A predictive equation called Jouyban-Acree model (JAM) was used to predict the volumetric properties of the binary mixture. The accuracy and capability of JAM were compared with regression model. The results revealed that JAM is capable of correlating volumetric properties very well and is an accurate model for prediction of the volumetric properties of the binary mixture. The analysis of variance (ANOVA) results showed that temperature and concentration are highly significant and have the strong influence on the volumetric properties. The investigation of experimental data shows that the density and molar volume values increase with rising in the concentration of DEA in the mixture, while isobaric thermal expansion values decrease. Moreover, there was an increasing trend on the values of molar volume and isobaric thermal expansion as the temperature increased, whereas the density of binary mixture decreased with an increase in temperature. [ABSTRACT FROM AUTHOR]

The present work systematically clarifies the influence of the atomic mixing and the atomic order (i.e. atomic constituent distribution or site occupancy preference on inequivalent sites of a crystal) on the molar volume of the binary sigma phase. We calculated the molar volumes of 21 binary sigma compounds with different atomic order by using EMTO-CPA (Exact Muffin-Tin Orbitals - Coherent Potential Approximation) method. The calculation results follow a similar trend as the experimental data. Moreover, the calculated molar volumes with respect to the composition of the sigma phase in disordered states show that the sigma compounds do not comply with the linear volume-composition relationship. This is due to the influence of the atomic mixing and the deviation can be either negative or positive depending on the tendency of electron loss or gain of the two constituent elements. Additionally, we compared the molar volume difference (ΔVm = V disorder -V order ) between the hypothetically disordered and ordered states of the binary sigma compounds. The results indicate that the effect of the atomic order on the molar volume of the sigma phase depends on the size difference and the electron configurations of the two constituent elements. [ABSTRACT FROM AUTHOR]

Relative permittivities, refractive indices, and densities of the various binary systems containing three primary diols (1,3-propanediol, 1,4-butanediol, and 1,5-pentanediol) and three similar structurally related aliphatic ketones (dimethyl-, diethyl-, and methyl ethyl-ketones) were measured and analyzed over the whole composition range at T = 298.15 K and p = 101.3 kPa. Various approaches were used to coherent data analysis and accomplish the purpose of the study. The formulations of the Kumbharkhane et al. and the Winkelmann-Quitzsch are required for a coherent interpretation and understanding of these binary systems. The experimental data of the binary systems and pure liquids were used to calculate the excess parameters, namely excess permittivity, excess free energy, excess molar volume, and excess refractive index. In this study, a Group Method of Data Handling (GMDH) type neural network was used to correlate the permittivity data. The proposed model gives excellent agreement with the experimental data. The model is shown to be appropriate for predicting the permittivity data. [ABSTRACT FROM AUTHOR]

The densities and sound speeds in the title system have been measured between 288.15 and 308.15 K in the whole concentration range. Additionally, refractive indices have been measured at 298.15 K. The results are interpreted in terms of deviations from the ideal values. It was found that this system is very close to ideality, much closer than such systems like mixtures of non-substituted hydrocarbons. The results allow to propose the mixtures of chlorobenzene with 2-chlorotoluene as a model system for testing different models of liquid mixtures for their ideality. [ABSTRACT FROM AUTHOR]

Comprehensive research into quaternary glass systems' structural, physical, and optical characteristics was conducted, specifically for glass series 60V 2 O 5 -20B 2 O 3 -(20-x)Bi 2 O 3 -xCaO, where x = 0-20 mol%. Using X-ray diffraction (XRD), their non-crystalline character was confirmed. Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) were used for morphological study to confirm glass formation. Several techniques were employed to investigate the effects of incorporating CaO on the physical, optical, and structural characteristics of glasses composed of bismuth boro-vanadate. As-prepared glass samples have been analysed to determine how density (ρ g), crystalline volume (V c r y s t ), molar volume (V m), and oxygen packing density (OPD) changes with composition. Additional determined physical parameters include interionic distance (R i), Calcium yields field (F), ion concentration of Ca2+ (N), and polaron radius (R p). DSC thermograms reveal that glass transition temperature (T g) rises in tandem with the concentration of calcium oxide, demonstrating an improvement in the glass system's thermal stability. FTIR and Raman spectroscopy examination of all glass samples confirmed that V 2 O 5 forms a network with VO 5 units. After x = 10 mol%, the proportion of non-bridging oxygens in the glass matrix rises as VO 5 units are converted into VO 4 units along with the transformation of BO 3 units into BO 4 units. Bi 2 O 3 is found in glass matrix in BiO 6 and BiO 3 units. As concentrations of calcium oxide were increased, UV–Visible spectroscopy revealed nonlinear trends in various optical parameters such as optical energy (E o p t) , Urbach energy (E U), cut-off wavelength (λ C), molar refractivity (R M), metallization criterion, and refractive index (n). The glasses prepared in this study exhibit high-level optical basicity (ranging from 1.164 to 1.238), electronic oxide ion polarizability (3.304–3.869), and metallization criterion (0.249–0.304). These findings point to the possibility that the glasses can be suitable for non-linear optical applications. • SEM and TEM analysis were employed for morphological study of the prepared glasses. • FTIR and Raman spectroscopy confirmed that V 2 O 5 forms a network with VO 5 units. • Indirect allowed transitions were found most suitable in the present studied glass system. • Studied glasses can be suitable for non-linear optical applications. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DESs) are derived from two or more salts as the hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs). In this work, DES namely allyltriphenyl phosphonium bromide-diethylene glycol (ATPPB-DEG) was prepared by using three molar ratios of 1:4, 1:10 and 1:16 salt to HBD. The volumetric properties of aqueous DESs, such as density, molar volume, isobaric thermal expansion, apparent molar volume and apparent molar expansibility were reported at several temperatures from 293.15 to 343.15 K. A mathematical equation, so-called Jouyban–Acree model (JAM), was used to correlate the experimental density and molar volume data of aqueous solution of DESs with respect to the concentration and temperature. The results disclosed that this model is an accurate and reliable model for the prediction of aqueous DES properties. The excess properties, such as excess molar volume and excess isobaric thermal expansion were reported and fitted to two different equations. In order to calculate the limiting apparent molar volume values, the apparent molar volume values were fitted into a Redlich–Mayer equation. By applying the Hepler equation, it was found that DESs with molar ratios of 1:4 and 1:10 are as structure-maker solutes, while the DES 1:16 is a structure-breaking solute in aqueous solutions at different temperatures. [ABSTRACT FROM AUTHOR]

Different glass samples were prepared in the system 59[(Pb x Ca 1 − x )O·TiO 2 ]-40[2SiO 2 ·B 2 O 3 ]-1Fe 2 O 3 (0 ≤ x ≤ 0.7) employing a rapid melt-quenching technique. The IR structural and optical properties were evaluated using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and ultraviolet-visible (UV–VIS) spectroscopy. The amorphous nature of the glass samples were confirmed using XRD and SEM analysis. The Archimedes principle was used to calculate the density of all glass samples. The density increased with decrease in CaO content and the trend of molar volume reciprocal to the density. The band gap energy of the prepared glass samples are in the range of 1.25–2.37 eV and decrease with an increase in the concentrations of PbO. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DESs) are derived from two or more salts as the hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs). In this work, DES namely allyltriphenylphosphonium bromide- triethylene glycol (ATPPB-TEG) was prepared by using three molar ratios; i.e.,1:4, 1:10, and 1:16 of salt to HBDs. The volumetric properties of aqueous mixture of DESs, such as density, molar volume, isobaric thermal expansion, apparent molar volume and apparent molar expansibility were reported at several temperatures from 293.15 to 343.15 K. A mathematical equation, namely Jouyban–Acree model (JAM), was used to correlate the experimental density and molar volume data. Furthermore, in order to calculate the limiting apparent molar volume values, the apparent molar volume values were fitted into a Redlich–Mayer equation. By applying Hepler equation, it was found that DESs 1:4 and 1:10 are as structure-maker solutes, while DES 1:16 is a structure-breaking solute in aqueous solutions. [ABSTRACT FROM AUTHOR]

Tracer ( 44 Ti) and inter-diffusion experiments were performed on identical pseudo-binary diffusion couples of the B2 Ni–Al–Ti system at 1411 K. The molar volume of B2 Ni–Al–Ti alloys was critically assessed via CALPHAD approach. The concentration dependencies of pseudo-binary interdiffusion and 44 Ti tracer diffusion coefficients are determined for both, constant and variable molar volumes. The results show that while interdiffusivities are sensitive to uncertainties in molar volume, the tracer diffusion coefficients are not. With a decrease of the molar fraction of Al in the pseudo-binary B2 Ni–Al–Ti alloy, the tracer diffusion coefficient of Ti is first decreased and then increased with a minimum around the composition corresponding to 48 at.% of Al and 3.5 at.% of Ti. [ABSTRACT FROM AUTHOR]

The present study is focused on synthesis and physicochemical properties of a new class of Deep Eutectic Solvents (DESs) based on Benzyltripropylammonium chloride as hydrogen bond acceptor (HBA) and different hydrogen bond donors (HBD) like phenol, ethylene glycol, glycerol and lactic acid. Several physicochemical properties such as, density, speed of sound, conductivity and refractive index of these four DESs have been measured in the temperature range of 293.15–343.15 K and used to calculate various derived thermodynamic properties. Further, rheological measurements have been carried out to understand the viscosity and flow behavior of these DESs and also the influence of different hydrogen bonding environment on the nature of DESs. The temperature dependent density and viscosity values have been fitted using second order polynomial and well-known Vogel-Tammann-Fulcher (VTF) equations, respectively The experimental results implies that both the type of HBD and temperature has significant influence on the physicochemical characteristics of the synthesized DES. [ABSTRACT FROM AUTHOR]

The heat capacity C P is calculated as a function of pressure at constant temperatures of 25, 40 and 51 °C for the solid and liquid phases of benzene near the melting point. For this calculation, the observed molar volume from the literature are used at various pressures for constant temperatures indicated through the thermodynamic relations in the solid and liquid phases of benzene near the melting point. Our calculated values of the difference in the heat capacity ( C P − C V ) decrease with increasing pressure at the constant temperatures studied which predict the observed behavior of benzene in the solid and liquid phases. This indicates that our method of calculating the heat capacity from the molar volume data is satisfactory at various pressures (at constant temperatures) near the melting point in benzene. The heat capacities of some other organic molecular crystals such as naphthalene, anthracene etc. can also be calculated from the molar volume near their melting points. [ABSTRACT FROM AUTHOR]

The ternary mixture methanol (MeOH)/formamide (Form)/acetonitrile (MeCN) was studied by means of refractive index and density measurements. Data for a total of 22 ternary mole fractions, and 19 binary mole fractions for each formamide containing mixture, as well as values from the previously studied methanol/acetonitrile mixture were obtained and evaluated. Excess properties were computed and modeled by polynomial equations, namely Redlich-Kister for binary fractions and Cibulka for ternary mixtures. Partial molar volumes were likewise calculated and together with previously published values allowed the interpretation of structural effects associated with molecular interactions. [ABSTRACT FROM AUTHOR]

The volumetric (partial and apparent molar volumes) and calorimetric properties (apparent heat capacities) of aqueous cationic polyelectrolyte solutions – ionenes – were studied using the oscillating tube densitometer and differential scanning calorimeter. The polyion's charge density and the counterion properties were considered as variables. The special attention was put to evaluate the contribution of electrostatic and hydrophobic effects to the properties studied. The contribution of the CH 2 group of the polyion's backbone to molar volumes and heat capacities was estimated. Synergistic effect between polyion and counterions was found. [ABSTRACT FROM AUTHOR]

2,6-Dihalogen atom substituted-9,10-anthraquinones are used as organic cathode materials for rechargeable lithium ion batteries. The differences in the cyclic voltammetry curves, voltage profiles and cycling performance of these compounds are analyzed. An important regularity is strikingly found: the lighter the density of a material, the easier is the achievement of the material’s theoretical capacity at the first scanning cycle. This finding gives an understanding to improve the practical specific capacity of lithium battery and a very clear direction to design new compounds in future so as to make full use of the theoretical capacities. [ABSTRACT FROM AUTHOR]

The present work is intended to establish the addition of the different modifier cations (Na, Li, Mg) along with different anionic combination (oxygen and fluorine) in the novel Lead boro-tellurite glass network in the point of view of radiation shielding material. The present novel lead boro-tellurite glasses have been synthesized following the melt quenching technique with three modifier elements (Na, Li, Mg) in the form of oxides as well as fluoride in the glass network. The variation in density and molar volume confirms the atomic rearrangements and FTIR spectral analysis reveals the presence of non-bridging oxygens in the prepared glasses. The optical absorption spectra confirm the changes in the bandgap due to the incorporation of modifiers into the glass network. The radiation shielding ability of the glasses were investigated by determining the transmission factor (TF) and other related parameters. The gamma photon attenuation abilities of the prepared Lead boro-tellurite glasses shows improved linear attenuation coefficient (μ), effective atomic number (Z eff) and half value layer (HVL) when the cations are incorporated in the form of fluorides. Authors found that the TF for NaO:Pr glass at a thickness of 0.6 cm increases from 0.69 at 0.3 MeV to 0.89 at 1 MeV, and 0.94 at 5 MeV. The TF results demonstrated that adding MgO instead of Na 2 O to the glasses reduces the number of photons that can penetrate the glass, enhancing the radiation-shielding properties of the glass system. Authors evaluated the effective atomic number (Z eff) and found that the Z eff values vary between 56.55 and 57.14 at 0.015 MeV. Also, the Z eff results confirmed that adding MgO into the glasses leads to a great increase in Z eff values. Among the prepared glasses, Mg2+ cations incorporated glass exhibits higher shielding efficacy and it may be suggested as a promising radiation shielding material. • Lead boro-tellurite glasses for Radiation shielding properties. • Triple component (Na, Li, Mg) in the form of oxides and fluorides. • Formation of bridging oxygen constitutes the glass to be a tightly packed structure. • LAC values increases with increase in density of the prepared glasses. • Among the prepared glasses Mean Free Path values are lesser for MgO:Pr glass. [ABSTRACT FROM AUTHOR]

The glasses of the 45Na 2 O− 10Bi 2 O 3 − (5-x)TiO 2 −xNb 2 O 5 − 40 P 2 O 5 system with 0 ≤x ≤ 5 mol% have been prepared by using the melt quenching route. The structure of these obtained glasses was analyzed by examining the density and molar volume measurements. It was found that the density increased from 3.237 g/cm3 at x = 0 mol% to 3.559 g/cm3 at x = 5 mol%. But for the molar volume, there were two changes; the first is characterized by an increase in molar volume from 59.316 cm3/mol (x = 0) to 59.767 cm3/mol (x = 1), and the second one is distinguished by a decrease in molar volume from 59.767 cm3/mol (x = 1) to 56.562 cm3/mol (x = 5). The obtained densities have been investigated in order to examine the radiation shielding properties of these study glasses using Phy-X software. The linear attenuation coefficients (LAC) results demonstrated that the protecting potential of the formed phosphate glasses decreases dramatically as the energy is changed from 0.284 to 1.33 MeV. The effective atomic number (Z eff) was also evaluated and we found that the Z eff for the glass with 5 mol% of Nb 2 O 5 , is in the range of 14.16–23.87. For the glass with free Nb 2 O 5 , we reported the folloiwng values for Z eff : 23.82, 16.68, 14.64 and 13.86 at 0.284, 0.511, 0.826 and 1.33 MeV. The half value layer (HVL) is determined and we found that the thickness of the sample must be sleected less than 1.5 cm to effectively attenuate the photons with energy less than 0.511 MeV. The different shielding factors showed that the prepared samples have a potential for protection at lower energies that is significantly greater than its shields at higher energies. Also, the addition of Nb 2 O 5 causes an enhancement in the radiation shielding performance. [ABSTRACT FROM AUTHOR]

• A comprehensive investigation on molar volume and surface tension of Al-Cu-Ag ternary system was performed. • The molar volume description of pure liquid Ag, the databases of molar volume and surface tension were constructed. • The surface tension of liquid alloys was predicted by Butler equation using a home-made code with CALPHAD-type parameters. • All the calculated results are in satisfactory agreement with the corresponding experimental data. • The present thermophysical databases could be applied to predict surface/interfacial energy then simulate microstructure. Thermophysical properties play an essential role in the microstructure simulation during precipitation and solidification processes in materials science and engineering. In this work, a comprehensive investigation on the molar volume and surface tension of the Al-Cu-Ag ternary system was performed by the CALPHAD (CALculation of PHAse Diagram) approach and the first-principles calculation. Based on the critical review of experimental and theoretical data, the molar volume description of pure Ag in the liquid phase, and subsequently the mole fraction dependent thermophysical databases of molar volume and surface tension for the Al-Cu-Ag system including metastable phases were constructed via the CALPHAD approach. Then considering the excess molar volume, the surface tension of solution alloys could be predicted by the Butler equation using a home-made code with the input of thermodynamic and thermophysical parameters. With the increment of temperature, molar volume of the alloys increases while the surface tension decreases. All the calculated results using the present parameters are in satisfactory agreement with the corresponding experimental data, which could be subsequently applied to simulate the microstructure evolution like precipitation kinetics and phase-filed simulation. [ABSTRACT FROM AUTHOR]

In this study, we calculate variation of the molar volume with the temperature at constant pressures (70.5, 85.2, 128 and 175.2 MPa) using the experimental data from the literature for the solid and liquid phases of benzene near the melting point. The calculated molar volume decreases in the solid phase as the temperature increases toward the melting temperature, whereas in the liquid phase just above the melting temperature it increases abruptly, as expected. By calculating the specific heat, thermal expansion and the isothermal compressibility from the molar volume, which increase with increasing temperature (at constant pressures), we construct the Pippard relations for the solid and liquid phases of benzene near the melting point. Our calculated molar volume and the thermodynamic quantities (specific heat, thermal expansion and the isothermal compressibility) agree to some extend with those experimental measurements from the literature for the molar volume (at 1 atm and constant pressures studied here) and the specific heat (at 0.1, 0.9 and 1.5 GPa), which also increase with increasing temperature for the solid and liquid phases near the melting point in benzene. Our calculated thermodynamic quantities and the Pippard relations can also be examined with the measurements at various temperatures at constant pressures given here near the melting point in benzene. [ABSTRACT FROM AUTHOR]

The room-temperature molar volumes of bcc (β), hcp (equilibrium α or martensitic α′), and orthorhombic (martensitic α′′) phases are modeled for a number of Ti-base solid solutions in the CALPHAD framework. The martensitic molar volume is continuous at the α′/α′′ transition composition. Hcp and orthorhombic structures are modeled separately, and the predicted martensitic structure is taken as the denser one. [ABSTRACT FROM AUTHOR]

In the paper published by the Satpathy and coworkers the excess parameters have been fitted to a Redlich-Kister polynomial equation for optimisation of data. Excess quantities were calculated from experimental values and are presented well in some curves as a function of mole fraction ( x 2 ) of cyanex 923 of the studied binary mixture. Nevertheless, the authors presented values of optimal adjustable parameters were not for the polynomial of the famous Redlich-Kister equation (i.e. versus x 2 – x 1 ), but originally for the excess quantity Y E expressed as an overall three degree polynomial on ( x 2 ) including implicitly the mole fraction product ( x 1 · x 2 ) in their non-linear regression analysis, which can make probable confusion for some investigators. Overall, the experimental data are valuable except the use of the non-appropriate equation along with non-optimal degree. Moreover, we have completed this study by additional discussion on the famous reduced RK excess functions to convince the readers as well as to reveal the existence of particular mixture composition indicating a structure breaking or weakening of interaction intensity which is supported by the non-linear regression with more polynomial degree. [ABSTRACT FROM AUTHOR]

The temperature and frequency dependent AC conductivity of some Ag 2 S doped chalcogenides is prepared in the laboratory and experimental data have been collected. Its structural analysis is carried out with X-Ray Diffraction and UV–Vis Spectroscopic methods. The estimated values of optical band gap energy, E g are found to increase with Ag 2 S content and the present system may be classified as allowed indirect band gap semiconductor. The density and molar volume of as-prepared samples have also been estimated. The AC conductivity of this system has been found to obey the Meyer-Neldel (MN) rule. The decrease of Meyer-Neldel characteristic energy E MN with compositions has been observed. Higher conductivity as well as hopping frequency should be caused due to highly conducting Ag 2 Senanophases, which is confirmed from DFT and Density of States (DOS) spectra. • New chalcogenide glassy system, xAg2S - (1-x) (0.5Se - 0.5Ge) has been developed. •Lowering of density and increasing of molar volume with Ag2S content are indicative of loosely packed structure with higher Ag2S content. •The estimated values of band gap energy indicate that the present chalcogenide system is of indirect band gap semiconductor. •Various peaks in XRD imply that the present chalcogenide system is polycrystalline in nature. •Dc conductivity shows thermally activated nature and AC conductivity via Meyer-Neldel (MN) rule has been established their correlated barrier hopping conduction nature. •Higher conductivity as well as hopping frequency should be caused due to highly conducting Ag2Se nanophases, which is confirmed from DFT analysis. [ABSTRACT FROM AUTHOR]

• Glasses are prepared by melt quenching method. • XRD confirmed the amorphous nature. • EPR spectra revealed the resonance peaks at g=4.2, 3.2 and 2.0. • The bond between Mn2+ ion and its ligands is Ionic. • Increase of NaF/KF increases the tetrahedral BO 4 units. The glass systems with the composition xMF-(40-x) CdO-59.5B 2 O 3 , (M=Na, K and x= 5, 10, 15, 20, 25, 30 and 35 mol %) doped with 0.5 mol % of MnO 2 were prepared using the melt quenching method. The glasses were analysed using XRD, UV-VIS, EPR and FTIR spectra. The optical band gap (E g) values of the glass systems were observed to increase from 3.21 eV [NFCBM1] to 3.48 eV [NFCBM7] and 2.56eV [KFCBM1] to 3.31 eV [KFCBM7] with increase of NaF/KF concentration which may be due to decreasing of the number of non bridging oxygens. The (Δg) values suggest the presence of Mn2+ ions in octahedrally coordinated complex and the A values suggest that the bond between Mn2+ ions and its ligand filed is ionic. The BO 4 atoms were increased in both NaF and KF containing glasses with increase in NaF/KF concentration. [ABSTRACT FROM AUTHOR]

The temperature and pressure dependences of molar volume of the solution phases in the Al–Cu–Mg system have been modeled by using the CALPHAD approach. Molar volumes of pure elements were critical assessed according to the experimental data from the literature. Subsequently, volumetric properties of the Al–Cu, Al–Mg and Cu–Mg binary systems were assessed and compared with the corresponding experimental data. The results are compatible with the assessed data. [ABSTRACT FROM AUTHOR]

Density, molar volume, refractive index and molar refraction have been correlated with the structural units in Sb 2 O 3 –B 2 O 3 glasses. It is proposed that these glasses include SbO 3 pyramids, BO 4 tetrahedra, symmetric- and asymmetric BO 3 units. Concentration of these units could be determined by using literature data of the fraction of four-coordinated boron atoms. Each of the structural units contributes to the studied properties by a factor that remains the same overall the entire composition region. Probable existence of certain fraction of Sb 5 + ions is discussed. It is deduced that the glasses can be treated by assuming the presence of SbO 3 as the sole structural unit of Sb 2 O 3 . [ABSTRACT FROM AUTHOR]

Grain boundary (GB) segregation of P in 2.25Cr1Mo steel induced by elastic stress shows that the P equilibrium concentration, after reaching the non-equilibrium concentration maximum at critical time, returns to its initial thermal equilibrium level. This finding confirms the interesting phenomenon that the effect of elastic stress on GB segregation of P is significant in kinetics while slight in thermodynamics. Through extending the “pressure” in classical theory of chemical potential to the “elastic stress”, the thermodynamic effect of elastic stress on GB segregation is studied, and the relationship between elastic stress and segregation Gibbs energy is formulated. The formulas reveal that the difference in the segregation Gibbs energy between the elastically-stressed and non-stressed states depends on the excess molar volume of GB segregation and the magnitude of elastic stress. Model calculations in segregation Gibbs energy confirm that the effect of elastic stress on the thermodynamics of equilibrium GB segregation is slight, and the theoretical analyses considerably agree with the experimental results. The confirmation indicates that the nature of the thermodynamic effect is well captured. [ABSTRACT FROM AUTHOR]

The inherent compressibility of biodiesel has strong impact on its dynamic properties, particularly under high temperature and pressure conditions. In order to clarify the connection between the microscopic chemical structure of organic liquids and their macroscopic compressibility, a qualitative method is proposed by using Molecular Adiabatic Compressibility (MAC). By analyzing sound velocity and density data of methyl and ethyl caprate, two-dimensional fitting expressions of MAC obtained in isobaric and isothermal curves respectively. Partial derivatives of two-dimensional expressions for pressure and temperature are introduced to quantify the dependency of MAC upon these parameters. Further, a sets of new three-dimensional expressions for MAC are proposed to demonstrate these dependency characteristics in P–T domain under the fuel working conditions of the injection system. Based on the definition of MAC, a new state equation was developed by integration of 3D fitting expression. The calculation results of molar volume indicate that the integral state equation is equivalent to the ESD model. The new fitting expression successfully captures the influence of temperature and pressure on the compressibility of organic liquid fuels, and reveal higher calculation accuracy of molar volume under extreme high pressure. [ABSTRACT FROM AUTHOR]

The molar volume of the C14 Laves phase has been evaluated at room temperature and atmospheric pressure for binary systems involving 31 elemental metals (i.e. Al, Ba, Be, Co, Cr, Fe, Hf, Lu, Mg, Mn, Mo, Na, Nb, Nd, Os, Pr, Re, Ru, Sc, Sm, Sr, Ta, Tb, Ti, Tm, V, W, Y, Yb, Zn and Zr) based on experimental data from the literature by means of the CALPHAD approach. The molar volume model adopted in the present work expresses the molar volume of a non-stoichiometric C14 Laves phase as a linear average of volumes of the constituting elements in the hypothetic C14 Laves structure. Model parameters have been obtained and yield reasonable descriptions of most experimental data. As a further comparison, the molar volume of the C14 Laves phase obtained by the first-principles calculations was compared with the assessment results which illustrates a reasonable consistency. [ABSTRACT FROM AUTHOR]

Sound velocities (u) and densities ( ρ ) of the binary liquid mixtures of green solvent ethyl lactate (EL) with isopropyl alcohol (IPA), propylene glycol (PG), and glycerol (GLY) and also in pure solvents are measured over the entire composition range at temperatures (303.15, 308.15, 313.15 and 318.15) K and atmospheric pressure. The excess molar volume ( V m E ), excess isentropic compressibility ( k s E ), excess partial molar volumes ( V ¯ m , 1 E , V ¯ m , 2 E ) and excess partial molar volumes at infinite dilution V − 1 E , 0 and V − 2 E , 0 are computed from density and sound velocity measurements. These results are fitted to the Redlich–Kister polynomial equation to estimate the binary interaction parameters. The variation of these parameters with composition and temperature is discussed in terms of molecular interaction on mixing and their interacting abilities are compared. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents are emerging as potential substitutes for ionic liquids in many chemical and engineering applications. The characterization of physico-chemical properties of these fluids is of high importance for process design and equipment sizing. Despite the few attempts in this area, the huge variety of DES types and structures necessitate the development of models with high prediction quality for calculating their basic physical properties. In this work, molar volume data for common types of DESs was collected as a function of temperature. The Racket model was analyzed and modified to be suitable for DES applications. A modified model was tested and validated with the experimental molar volume DES data. An average percentage deviation of 0.211% was attained. This is about one third the deviation achieved when using the Rackett original model. The newly developed model, can be utilized for predicting molar volume and density in process simulators calculations as well as during the design and operation stages of processes involving the use of DES. [ABSTRACT FROM AUTHOR]

As the increasing demands of compact and space-saving electronics, capacitors with high energy-storage density are eagerly desired. One of the greatest challenges in the development of new high energy density materials is to increase dielectric permittivity. In this present work, we present some first results relative to phosphate glasses, which could be used as the dielectric energy-storage materials to fabricate high energy density devices. They were prepared by means of rapid quenching method. DTA and X-ray diffraction analysis were used to control their vitreous states. Dielectric constant of the glasses was measured at the frequency from 1 Hz to 1 MHz under the testing temperature from 120 K to 360 K. The results indicated that some samples exhibit high dielectric properties. [ABSTRACT FROM AUTHOR]

The molar volume of the sigma phase has been modeled and evaluated at room temperature and atmospheric pressure for binary systems concerning 19 transition elements Au, Co, Cr, Fe, Ir, Mo, Nb, Ni, Os, Pd, Pt, Re, Rh, Ru, Ta, Tc, V, W and Zr by using the CALPHAD approach. The volume model proposed in this work expresses the molar volume of a non-stoichiometric sigma phase as a linear average of volumes of the constituting elements in their hypothetic sigma structure, which can be assessed as model parameters based on experimental data from the literature. Reasonable model parameters have been obtained giving a best description of most experimental data. For comparison, volumes of the 19 transition elements in the sigma structure have been calculated by first-principles calculations. The results are compatible with the assessed values. [ABSTRACT FROM AUTHOR]

The relationship between the network structure and properties of iron containing novel oxyfluorophosphate glasses with the composition 20ZnO–20CaF 2 –(60 − x)P 2 O 5 :xFe 2 O 3 with 0 ≤ x ≤ 5 mol% has been studied. The density, molar volume, oxygen molar volume and oxygen packing density studies helped to understand the structural changes occurring in these glasses. The dissolution rate and pH of the immersion liquid are measured to explain the chemical durability of the glasses. Differential thermal analysis studies are carried out to analyze the thermal stability of the studied glasses. Deconvoluted infrared and Raman spectra of the glasses are analyzed to determine the relative areas of the vibrational bands corresponding to different structural units. Analysis of the vibrational spectra in conjunction with the other properties reveals that Fe 2 O 3 enters the glass matrix in the form of Fe 2 + and Fe 3 + ions through the formation of more stable P O Fe 2 + and P O Fe 3 + bonds at the expense of easily hydrated P O P bonds. [ABSTRACT FROM AUTHOR]

A model has been presented to correlate both the density and molar volume of Bi 2 O 3 –B 2 O 3 glasses with the structure. The model makes use of the available data of the fraction of four coordinated boron to get the concentration of all structural units. The concentration of BO 4 units shows a maximum at ~ 31 mol% Bi 2 O 3 . There is a nonlinear decrease in the concentration of symmetric BO 3 units and an increase in the concentration of BiO 6 units. Asymmetric BO 3 units start forming for Bi 2 O 3 > 42 mol%. It is deduced that in BiO 6 units, oxygen atoms are four coordinated with Bi atoms. The model is able to fit the calculated and experimental density and molar volume and explains the minimum in the molar volume at 22 mol% Bi 2 O 3 . [ABSTRACT FROM AUTHOR]

Highlights: [•] We report solution properties of glycine betaine in aqueous NaCl solutions. [•] Study indicated the dominance of electrostatic interactions in the systems. [•] Experimental results have been compared with the literature. [•] Size of the metal ions found to influence the volumetric properties. [ABSTRACT FROM AUTHOR]

Infrared spectra of xBaO ⋅ (30-x)PbO ⋅ 70B2O3, xBaO ⋅(40-x)PbO ⋅ 60B2O3 and xBaO ⋅ (50-x)PbO ⋅ 50B2O3 glasses have been quantitatively analyzed. The fraction of four coordinated boron atoms varies linearly, for each group, between the values of the corresponding binary borate glasses. The data could be used to calculate and follow the composition dependence of the concentration of structural units in all glasses. The results show a linear increase in the ratio of PbO forming BO4 units to the total content of PbO, with increasing B2O3 in binary PbO-B2O3 glasses. Similar behavior has been observed for the ratio of BaO forming BO4 units to the total content of BaO in binary BaO-B2O3 glasses. The ratio of PbO forming PbO4 units to the total PbO content, and that of BaO forming asymmetric BO3 units to the total BaO content, shows a reversed dependence. The linear change in fraction of four coordinated boron atoms and in density and molar volume suggests that the studied glasses can be treated as mixtures of binary PbO-B2O3 and BaO-B2O3 matrices. [ABSTRACT FROM AUTHOR]

Abstract: The fluidity, Φ, of molten salts is re-examined with critically compiled data applicable to 75 salts of various charge types. Various theoretical approaches, based on the corresponding states principle applicable to molten salts, are briefly presented. They are compared with the much simpler approach of Hildebrand and Lamoreaux: Φ= −B +(B/V 0)V that relates the (temperature dependent) fluidity to the (temperature dependent) molar volume V of the molten salt. This approach yields at the corresponding temperature of 1.1 T m the B parameters that are linearly related to the cohesive energy and the V 0 parameters that are 87% of the molar volume, signifying the absence of free volume. [Copyright &y& Elsevier]

Abstract: The fluidities, Φ = η −1, of room temperature ionic liquids (RTILs) as functions of the temperature can be described in terms of the Hildebrand and Lamoreaux approach. This relates the (temperature dependent) fluidity to the (temperature dependent) molar volume V of the RTIL: Φ=B[(V − V 0)/V 0]. The resulting V 0 parameters, signifying the absence of free volume, are 99.0±0.5% of the molar volume at 298.15K. Counter to expectation, the B parameters increase with the interionic attractive forces. It is shown that the volumetric behavior of the RTILs permits the prediction of the temperature dependence of their viscosities, provided that the latter are not larger than ca. 50mPas−1. [Copyright &y& Elsevier]

The effect of alkaline earth oxide on sodium tetraborate was analyzed by fabricating a range of glasses depicted by the formula x MgO-(40-x)ZnO-59.5Na 2 B 4 O 7 -0.5MnO 2. Basic character was analyzed and confirmed by XRD tests.Decline in density is attributed to the replacement of high molecular mass ZnO by a relatively less molecular mass MgO. The volume enlargement is discussed in terms of increased bond lengths and induced non- bridging oxygen atoms. Parameters like refractive index, reflection loss, molar refractivity, electron polarizability are obtained from existing relations. All these are indirectly depends on density and molar volume and hence their nature. Optical studies revealed indirect kind of transitions in these glasses ranging the values of optical energy gap between 2.913–3.15 eV and Urbach energy (ΔE) 0.342–0.276 eV showing greater stability of glasses.Mn2 +ion in its d5 state revealed a well resolved sextet centered around g"2.032 indicating Mn2+ ions are in octahedral (Oh) environment resulted from jumps between lower doublet energy states. The resonance of g≈ 2.99 and g≈ 4.22 are related to rhombic surroundings of the Mn2+ and jumps between middle kramers doublets. The value of hyperfine split 'A′ and Δg= (g e -g) are indicative of ionic bonding between Mn2 + ions and oxygens. Zero field splitting parameter 'D′ decreases from x = 0 to x = 30 mol% and then increased for x = 40 mol%. Magnitude of unpaired spins(N) participating in the resonance and paramagnetic susceptibility(c) are calculated. FTIR and Raman studies are conducted. FTIR spectra revealed the structural changes from BO 4 to BO 3 by increasing MgO content. From FTIR and Raman studies it is established that MgO is acting as modifier in the given glass composition. • Zinc sodium tetraborate glasses doped with manganese ions. • Density of the glass samples decreased with MgO content. • The EPR hyperfine distribution centered on g ∼2.032 is associated with Mn2+ in an octahedral environment with low distortion. • FT-IR spectroscopy of the fabricated samples refers to the transformation of the structural unit BO 4 into BO 3. • Raman spectroscopy suggested that at higher wavenumber, B –O stretching in metaborate groups in [BO 3 ] observed with one or two NBO's. [ABSTRACT FROM AUTHOR]