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In the current research, silver (Ag) nanoparticles were synthesized by chemical reduction method and polyethylene–silver nanocomposites containing different Ag contents (0–30 mass%) were fabricated by mechanical milling method. All samples were characterized by X-ray diffraction, UV–Vis spectroscopy, scanning electron microscopy, and transmission electron microscopy. Thermal behavior of these nanocomposites was investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis. The results of the DSC tests showed that although the melting temperature (T m) of PE and its nanocomposites has the same value, the crystallization temperature (T c) increases by addition of silver nanoparticles (Ag NPs) in the PE matrix, indicating that the Ag NPs act as nucleation sites. Also, crystallinity index of PE and its nanocomposites was calculated. Results show that the crystallization index changes from 45.74 to 57.36% as Ag NPs content increases from 0 to 30%. The mass loss of nanocomposites was lower than that of the pure PE, which could be attributed to the undecomposed Ag NPs.

In the previous studies, the GMA (Goharshadi–Morsali–Abbaspour) equation has been extended to the long chain n-alkanes, alcohols, amines, ketones, 1-carboxylic acids and esters via the group contribution method (GCM). The new proposed equation was named GCM-GMA equation. In this work, we have extended the GCM-GMA equation to predict the molar density of long chain ethers and glycol ethers and the binary and ternary mixtures of different organic compounds with ethers and glycol ethers. Each of these organic compounds has been assumed as a hypothetical mixture of methyl, methylene, and a functional group. Then, the GMA equation has been modified for such a hypothetical mixture. Propane, n-butane, n-hexane, 1-pentanol, 2-pentanol, and diethyl ether have been used to investigate the contribution of the different segments in the GCM-GMA equation parameters. The calculated parameters along with the GCM-GMA equation have been used to calculate the molar density of different long chain ethers and glycol ethers and their binary and ternary mixtures. The values of statistical parameters between experimental and calculated density show the ability of this equation to predict the density of these organic compounds. The GCM-GMA equation has been compared with four cubic equations of state. The results show that the GCM-GMA gives better results than other methods. Also, the excess molar volumes of some binary mixtures have been calculated from the density data at different temperatures.

In this work, the extended Lennard–Jones potential-based equation of state (ELJ-based EoS) on which the effective near-neighbor pair interactions are LJ (12,6,3) type has been extended to predict the density and other thermodynamic properties of hydrocarbons up to extremely high temperature, high pressure (HTHP) conditions. It seems that, at least in the dense regions, there are no upper and lower density limitations in the applicability of the model for different hydrocarbon systems. Having the temperature dependence of the parameters of new EoS, the parameters can be determined at any temperature for each of 38 studied compounds, including short- and long-chain alkanes ranging from CH 4 to n-C 40 H 82 , and also several cycloalkanes, highly branched alkanes and aromatic hydrocarbons. The calculated parameters have been used to calculate the density and other derived thermodynamic properties of different hydrocarbons at any temperature and pressure. The results show that ELJ-based EoS is clearly superior to those obtained using previous works in accord with experimental data up to HTHP conditions.

Magnetic nanofluids, ferrofluids, are a special category of smart nanomaterials, consisting of stable dispersion of magnetic nanoparticles in different fluids. In this study, magnetic nanoparticles of hematite, α-Fe2O3, were prepared by solvothermal method using Fe(NO3)3 as a starting material. The nanoparticles were characterized by X-ray diffraction (XRD) and transmission electronic microscope (TEM). To the best of our knowledge, this is the first research on the rheological properties of nanofluids of α-Fe2O3 nanoparticles and glycerol. The experimental results showed that the viscosity of α-Fe2O3-glycerol nanofluids increases with increasing the particle volume fraction and decreases with increasing temperature. Our results clearly showed that the α-Fe2O3-glycerol nanofluids are non-Newtonian shear-thinning and their shear viscosity depends strongly on temperature. The experimental data were compared with some theoretical models. The measured values of the effective viscosity of nanofluids are underestimated by the theoretical models.

In the present work, we have used a simple equation of state called the GMA EoS to calculate the density of three ionic liquid mixtures including 1-butyl-3-methylimidazolum hexafluorophosphate, [BMIM] [PF6] + methanol, 1-butyl-3-methylimidazolum tetrafluoroborate, [BMIM] [BF4] + methanol, and [BMIM] [BF4] + ethanol at different temperatures, pressures, and compositions. The isothermal compressibility, excess molar volumes, and excess Gibbs molar energy of these mixtures have been computed using this equation of state. The values of statistical parameters show that the GMA EoS can predict these thermodynamic properties very well within the experimental errors. The results show that isothermal compressibility of ionic liquids is lower than alcohols and the effect of temperature and pressure on the isothermal compressibility of ionic liquids is lower than alcohols. The excess molar volumes and excess molar Gibbs energy for these ionic liquid mixtures with alcohols are all negative at various temperatures and pressures over the whole composition range. The results have been interpreted in terms of intermolecular interactions and structural factors of the ionic liquids and alcohols.

In this work, we have calculated the densities of two mixtures composed of 1-propanol + toluene and ethanol + toluene at different temperatures, pressures, and compositions using GMA equation of state (EoS). We have also calculated some thermodynamic properties of these mixtures such as isobaric thermal expansion coefficient, isothermal compressibility coefficient, internal pressure, and excess functions such as the excess volumes, excess Gibbs free energy, excess enthalpy, excess entropy, excess internal energy, and excess Helmholtz free energy. A wide comparison with the experimental data shows the ability of this equation of state to reproduce and predict different thermodynamic properties. The composition dependence of the parameters of this equation of state has been assumed as quadratic functions of mole fraction. Using these quadratic mixing rules, the excellent agreement has been obtained between the calculated values and experimental data. To assess the validity of GMA EoS, the density of studied mixtures has been calculated based on this equation of state and Tait equation and compared using statistical parameters. The lower values of statistical parameters obtained by GMA EoS for these mixtures confirm the ability of this EoS to reproduce and predict the density of mixtures.