A new setup for speed of sound measurements and experimental data for nanofluids Al2O3 or Ag with water or ethylene glycol

The speed of sound of four different nanofluids consisting of Ag or Al2O3 nanoparticles and water or ethylene glycol base fluid is measured in the temperature range (298.15–343.15) K and at atmospheric pressure. One aim of this analysis is to learn whether the change from pure base fluid speed of sound to the nanofluid situation is a smooth or disruptive transition when adding nanoparticles. The measurements were conducted on the newly proposed apparatus consisting mainly of function generator, ultrasonic sensor, switch, voltage source, oscilloscope, ultrasonic container and the necessary sensors and equipment for data acquisition. The values for speed of sound were calculated based on the Time of Flight method. Deionised water and ethanol were used to calibrate the apparatus which is additionally tested with pure base fluids water and ethylene glycol and showed excellent agreement with average absolute percentage deviations between experimental and literature data for speed of sound of 0.12% and 0.36%, respectively,. Beside the temperature influence, the influence of the nanoparticle concentration on the speed of sound of nanofluid were investigated and followed. The analysis of the sound velocity allows insight into the molecular level interactions taking place between the nanoparticles and the base fluid molecules of the nanofluid. The decrease in velocity values with the increase of concentration, noticeable in the tested nanofluids, is a result of decrease in nanoparticle-fluid interaction and dominance of particle–particle interaction

Transport properties of binary liquid mixtures - Candidate solvents for optimized flue gas cleaning processes

Thermal conductivities and viscosities of three pure chemicals, monoethanolamine (MEA), tetraethylene glycol dimethyl ether (TEGDME) and polyethylene glycol 200 (PEG 200) and two binary mixtures (MEA++TEGDME and MEA+ PEG 200) were measured at six temperatures: 298.15, 303.15, 308.15, 313.15, 318.15 and 323.15 K and atmospheric pressure. Measurement of the thermal conductivities was based on a transient hot wire measurement setup, while the viscosities were measured with a digital Stabinger SVM 3000/G2 viscometer. From these data, deviations in the thermal conductivity and viscosity were calculated and fitted to the Redlich-Kister equation. Thermal conductivities of mixtures were correlated using the Filippov, Jamieson, Baroncini and Rowley models, while the viscosity data were correlated with the Eyring-UNIQUAC, Eyring-NRTL and McAlister models

Thermodynamic study of triacetin or ethyl levulinate and alcohol binary mixtures

The subject of presented research is the study of liquid binary mixtures consisting of ester and alcohol combination; triacetin or ethyl levulinate, as one component, and ethanol or isobutanol, as second component. Thermodynamic and transport data were measured in the broad temperature range, T=(288.15/298.15–323.15/333.15) K, and at atmospheric pressure, p = 0.1 MPa. All corresponding excess and deviation properties were calculated including the excess molar volume, viscosity deviation, refractive index deviation, isentropic compressibility deviation and excess molar Gibbs energy of activation of viscous flow, and correlated with the basic Redlich-Kister equation. The analysis of possible chemical interactions and structural effects taking place in the mixtures was led in the terms of ester structure, complexity of ester molecule and chain length and branching of the alcohol molecule. The thermodynamic analyses showed change of the sign of the excess molar volume depending on the alcohol present in the mixture. FT-IR spectra were recorded for all four systems for the compositions where maximum excess molar volumes are obtained to support the conclusions derived from the mixtures’ nonideal behaviour. In addition, modelling of viscosity is performed with the two- and three-parameter correlative models, as well as excess molar volume correlation with the Peng-Robinson equation of state and three-parameter van der Waals mixing rule

Volumetric and transport properties of binary liquid mixtures with 1-ethyl-3-methylimidazolium ethyl sulfate as candidate solvents for regenerative flue gas desulfurization processes

This paper presents novel data on density, viscosity and refractive index of four binary mixtures constituted of ionic liquid 1-ethyl-3-methylimidazolium ethyl sulfate and N-methyl-2-pyrrolidone/or 1-hexanol/or liquid polyethylene glycols with molar mass 200/or 400, in the temperature range from T = 288.15 K to 333.15 K and at pressure of p =.1 MPa. Thermal conductivity has been measured for mixtures of ionic liquid and polyethylene glycol 200/or polyethylene glycol 400 in the temperature range from T = 303.15 to 323.15 K and at a pressure of p =.1 MPa. All these solutions have the potential for application in regenerative flue gas desulfurization processes. From experimental values of densities, viscosities, thermal conductivities and refractive indices, excess molar volumes and deviations in viscosity, thermal conductivity and refractive index have been calculated and correlated with Redlich-Kister polynomial equation. The values of excess and deviation functions were used for analysis of molecular interactions present in the investigated solutions. In addition, modeling of transport properties, viscosity and thermal conductivity, was carried out and the obtained results were interpreted taking into account the applied approaches and models

Volumetric and Transport Properties of Isoamyl Acetate Based Binary Systems-Experimental Determination and Modeling

Three binary mixtures consisting of isoamyl acetate and 1-butanol or isobutanol or isopentanol were experimentally investigated in terms of their density, viscosity refractive index, and ultrasonic speed of sound, in the temperature range from 288.15 to 323.15 K and at atmospheric pressure. The choice of mixtures was based on their potential for practical application. From experimental data, excess molar volume, viscosity deviation, excess molar Gibbs free energy of activation of viscous flow, deviation in refractive index, and deviation in isentropic compressibility are calculated, correlated with the Redlich-Kister equation and used for better understanding of molecular interactions between the mixture components. Also, partial molar volumes, excess partial molar volumes, and partial molar volumes at infinite dilutions were calculated to elucidate the nonideal behavior of the investigated mixtures. Since the mixtures were investigated both from the theoretical point of view and with the aspect for practical application, the modeling of two key properties, viscosity and excess molar volume, was performed with different models and approaches, and the results are compared with experimental values

Free volume theory and extended mixing rule implementation for estimation of liquid viscosity of flue gas desulphurization candidate solvents

The free volume theory model was used to estimate viscosity of eight pure substances and their twenty-three binary mixtures. The selected viscosity data included compounds such as alcohol, ether, lactam, amine and polymer, measured at atmospheric pressure and in the temperature range (288.15–318.15/323.15/333.15) K depending on the used pure chemical. For pure substances free volume theory is a correlative three-parameter model, while for mixtures different approaches were tested regarding the number of parameters in the proposed extended logarithmic mixing rule, and showed that the optimal one in terms of complexity and yet with good results, also has three parameters to be optimized. The usage of the simplified model, without dilute gas term, was justified by the values of absolute average deviations for both pure component and mixtures. The model was also coupled with different equations of state (Peng-Robinson and Soave-Redlich-Kwong) for calculation of needed density data, in cases when experimental density data are missing. For pure chemicals, values of absolute average deviations are up to 2.3% for tested polymers, and below 0.8% for other classes of chemicals. For binary mixtures overall deviations go to 1% for eleven systems without polymer and to 3.8% for twelve systems with polymer as one compound. Comparison with friction theory is slightly in favor of friction theory for pure compounds, but involves higher number of parameters, while for the mixtures free volume theory showed significantly better results with the same number of optimized parameters. © 2022 Elsevier B.V

Radioactivity level and concentration of metals in waters around power plants application of potential method for pollution assessment

Human activities may lead to increased levels of naturally occurring radioactive material and heavy metals in waters relative to undisturbed natural environment, consequently to reduced safety of environment. Therefore, evaluation of water quality from coal-fired power plants is essential to both environmental protection and protection of the human health. In this paper the concentrations of metals (K, Sr, and Pb) and corresponding radionuclides (K-40, Sr-90, and Pb-210) for 22 water samples in the vicinity of five coal-fired power plants in Serbia were determined. The total metal concentrations were measured using an atomic absorption spectrometer. The activities of radionuclides K-40 and Pb-210 were determined by gamma spectrometry using HPGe detector, while the activity of Sr-90 was determined by radiochemical analytical method and measured using low-level gas proportional counter. The water pollution status was assessed by the prospective method that is defined in this study. The preliminary results indicated that operation of the coal-fired power plants has no significant impact on the surrounding environment with regard to the radiological characteristics and content of metals of the investigated waters that can be used for suitable in future applications