Viscosity Data Research Articles

A viscosity study of charcoal-based nanofluids towards enhanced oil recovery

Research into nanofluids for enhanced oil recovery (EOR) has been carried out for more than a decade. Metal oxide nanoparticles dispersed in water are usually applied and the nanofluids can recover 8–16 % more of the original oil in place after or comparing to water flooding, while the oil recovery capacity of carbon tube nanofluids can be even better. Higher viscosities of nanofluids than that of water are one of the key properties that contribute to their good performance in EOR. This work, for the first time, prepared nanofluids from two charcoal samples as well as an active carbon sample for their possible application for EOR. The relationship of nanofluid viscosities with pH values as well as nanoparticle concentrations of the nanofluids was studied for their viscous behaviour in different shear conditions. Their representative viscosity data measured at 100 rpm were examined for the values of the so-called Dispersion Factor (DF). The determined DF values for the charcoal-based nanofluids are close to those of metal oxide nanofluids that have much smaller nanoparticle sizes. The highly porous active carbon nanofluid showed strong viscosity enhancement that is comparable to the values reported for nanofluids of carbon nanotubes. Due to their significant viscosity enhancement and carbon sequestration feature, the charcoal-based nanofluids are promising to be used for EOR.

Insights into the physicochemical properties of newly synthesized benzyl triethylammonium chloride-based deep eutectic solvents

In order to utilize deep eutectic solvents (DESs) as a replacement for conventional organic solvents for different applications, a detailed understanding of their physicochemical properties is extremely important. In this study, several novel DESs based on benzyl-triethylammonium chloride (BTEA) as a hydrogen bond acceptor (HBA) and acids/or alcohols as hydrogen bond donors (HBDs) have been synthesized. DESs have been thoroughly characterized and investigated for their physicochemical properties viz. thermal stability, glass transition temperature, viscosity (η), surface tension (γ), refractive index (nD), density (ρ), speed of sound (u), and conductivity (κ) in a temperature range of 293.15–343.15 K. The effect of temperature, type of HBDs, and alkyl chain length of HBDs of the DESs on the physicochemical properties are critically examined and discussed. Viscosity data are fitted to Vogel-Fulcher-Tamman (VFT) and Arrhenius models. A linear model was used to fit surface tension (γ), density, refractive index, and speed of sound data whereas conductivity data were fitted to a nonlinear equation. Primary data on physicochemical properties have been used to estimate the viscous flow parameters (activation entropy, activation enthalpy, and free energy of activation) and other derived parameters such as lattice energy, standard entropy, molar volume, intermolecular free length, and isentropic compressibility. A relationship between molar conductivity and dynamic viscosity has been established to evaluate the ionicity of the synthesized DESs. Insights into the structure–property correlations are discussed in detail.

Transport and optical properties of the binary liquid mixture containing 1,3-diaminopropane and alkyl acetates (C1-C4) at T= (303.15-318.15) K: experimental investigations and theoretical modelling

ABSTRACT Physicochemical properties of pure liquids and their liquid mixtures at different compositions and at different temperatures have a significant role in the optimisation of chemical processes. Present report involves the analysis of the physicochemical properties of 1,3-diaminopropane and alkyl acetate. The viscosity () and refractive index () of 1,3-Diaminopropane, 1,3-DAP (1), with alkyl acetates, AAc, (C1-C4) (2) were measured at different temperatures (T = 303.15 to 318.15 K) under the atmospheric pressure 0.1 MPa. Deviation in viscosity, , deviation in refractive index, , and excess Gibbs free energy of activation, for these binary mixtures were calculated from measured viscosity and refractive index data and fitted to Redlich-Kister polynomial equation (R.K.). The data were analysed in terms of the Graph theoretical approach (GTA) to study the interactions in binary mixtures. The values were also correlated by using Bloomfield and Dewan (BFD) model and various correlations. data were correlated by various relevant correlations.

Fundamental Structure–Function Relationships in Vegetable Oil-Based Lubricants: A Critical Review

Vegetable oil (VO)-based lubricants are environmentally friendly replacements for mineral oils. This work critically reviews the literature and identifies the molecular structures in VO-based lubricants which have been used to improve performance. The specific roles that size, type, number, position, spatial arrangement, and symmetry play in determining lubricating functionality were highlighted. Data were systematically collected to identify the contributions of major structural components and relate them to specific physical functionality measurables. The relationships were presented to reveal structure–function trends. Empirical predictive relationships between flow and thermal transition properties and structures were established. Molecular mass was revealed to be a fundamental determinant of viscosity and transition temperatures, but these properties were shown to also be influenced by other structural factors such as polar functional groups, branching, and symmetry. Almost all the examined viscosity data plotted versus molecular mass are enclosed within the 95% prediction band of an exponential rise to a maximum function (R2 = 0.7897). Generally, for both flow and thermal transition, a given structure versus function follows simple linear or exponential functions with unbranched VO-based lubricants, lending themselves more easily to strong correlations. This review is a first step towards comprehensively relating structure to lubrication function. The revealed relationships of structural contributions to the lubricating functionality of VO-based lubricants provide insights that may be used to extend the ranges of chemical and physical properties of some molecular architectures examined.

The Viscosity of Na2O-B2O3-CaO-SiO2-Al2O3 Slags

The molding powder is an important supplement material in the continuous casting process, which plays a decisive role in the condition of continuous casting and the surface quality of the slab. The viscosity of the Na2O-B2O3-CaO-SiO2-Al2O3 slag system was studied by using the internal cylinder rotation method, and the viscosity data within the range of experimental slag composition were analyzed. The result shows that the viscosity of slag decreases gradually with the increase of borax (Na2O·2B2O3) content, where the content of O2- in the slag increases and the polymerization degree of the network structure decreases in the slag. When the Al2O3 contents increase, the amount of free oxygen decreases in the slag, which increases the degree of polymerization of the slag structure and results in the viscosity increasing. The calculation result of the prediction equation for viscosity has a small deviation.

Are volcanic melts less viscous than we thought? The case of Stromboli basalt

Melt viscosity is one of the most critical physical properties controlling magma transport dynamics and eruptive style. Although viscosity measurements are widely used to study and model the flow behavior of magmas, recent research has revealed that nanocrystallization of Fe–Ti-oxides can compromise the reliability of viscosity data. This phenomenon can occur during laboratory measurements around the glass transition temperature (Tg) and lead to the depletion of iron and titanium in the residual melt phase, with a significant increase in viscosity. Accurate viscosity measurements play a crucial role in determining the reliability of empirical models for magma viscosity, which are used to evaluate eruptive scenarios in hazardous areas. Here, we quantify the reliability of empirical models by elaborating a new viscosity model of Stromboli basalt that relies exclusively on viscosity data obtained from nanocrystal-free samples. We show that empirical models so far used to estimate melt viscosity at eruptive conditions overestimate Stromboli viscosity by a factor ranging between 2 and 5. In the context of numerical modelling of magmatic processes at Stromboli volcano, we analyse and interpret this finding. Based on our findings, we draw the conclusion that Stromboli basalt is anticipated to ascend from the storage area to the vent at a faster rate than previously hypothesized.

Making leavened bread from nixtamalized whole sorghum

The aim was to determine whether nixtamalized sorghum can induce viscoelastic properties in dough-like systems and to compare its kafirin-gluten-forming properties with those reported for wet wheat gluten. By utilizing dry nixtamalization, it was observed that bread had regular loaf volume, but stiff crumb texture. Therefore, wet nixtamalization accompanied by an additional steeping period was employed. Whole sorghum dough has high G′, G’’ and complex viscosity data η* and K due to highly structured dough, suggesting cross-linked intermolecular kafirins. To the best of our knowledge, wet kafirin-gluten and whole leavened sorghum bread was obtained from sorghum using nixtamalization for the first time. The crumb was attractive and significantly softer but still needed to improve in volume for comparison with bread made of refined wheat flour. An interesting feature noted is that the non-nixtamalized sorghum sample presented relatively low springiness (0.929). In sorghum proteins, the main absorption band of the α-helix increased in nixtamalized treatments as compared to the control (non-nixtamalized) and was associated with an increase in springiness in the bread. This is an important starting point for improving the breadmaking of whole sorghum bread.

Modeling of biopharmaceutical UF/DF from laboratory to manufacturing scale

The development of ultrafiltration and diafiltration (UF/DF) processes in the biopharmaceutical industry is largely empirical and rarely mechanistic. As a result, the full potential of process understanding is not unleashed. In this study, a model for a biopharmaceutical UF/DF process is introduced and applied for a Fab fragment from lab to manufacturing scale using a Ultracel Pellicon® 3 C-Screen cassette. For model calibration viscosity data, membrane permeability and a single ultrafiltration experiment were used. The calibrated model responded correctly to extrapolating process conditions regarding the control parameters crossflow and transmembrane pressure (TMP). This was demonstrated by a multivariate dataset of ultrafiltration experiments ranging from a protein concentration of 5 g/L to 200 g/L. The validated model was used to predict the entire UF/DF process at lab and manufacturing scale.

Data-Driven Virtual Viscosity Meter Augments Inline, Laboratory Measurements

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 211393, “Introducing Data-Driven Virtual Viscosity Measurements,” by Volodmir Karpan, Shell, and Samya Al Farsi and Hanaa Al Sulaimani, SPE, Petroleum Development Oman, et al. The paper has not been peer reviewed. _ For polymer-based chemical flooding projects, controlling the viscosity of the injected polymer solution is critical because polymer cost is one of the more significant elements in project economics. The polymer viscosity is measured routinely in the laboratory using fluid samples taken manually at different sampling points. In the case of large-scale projects, however, such viscosity monitoring becomes time-consuming and requires a dedicated field staff. The complete paper introduces a data-driven virtual viscosity meter (VVM) as a tool to augment inline and laboratory viscosity measurements. Introduction In field conditions, proven ways to monitor polymer viscosity of the injected solution include laboratory measurements using injector wellhead samples and inline measurements using a viscometer. In the former, injected chemical solution is sampled regularly to test its viscosity in the laboratory. This is a time- and labor-intensive method with safety and environmental risks during sampling. The latter method is a way to monitor viscosity using inline viscosity-measurement devices. Measuring the viscosity inline reduces the risk of polymer degradation significantly and provides more viscosity data. An inline viscometer uses pressure-drop and flow-rate measurements for the fluid flowing in a bypass line. Pressure drop is measured in the insulated coiled tube, while the flow rate is measured using a Coriolis-type flowmeter. During operation, the polymer solution temperature and pressure drop at a fixed flow rate are measured continuously. The system then calculates the viscosity of the polymer solution passing through the viscometer using the curve extrapolated from the calibration points. Such a viscometer measures a wide range of polymer viscosity and could be used for both high-viscosity and diluted solutions at low and high pressures. Use of inline viscosity measurement, while advantageous in many ways, comes with significant costs. An inline viscometer usually is installed on the foundation in a cabinet to protect it from harsh weather conditions (Fig. 1). Additionally, the injection line upstream of the wellhead must be equipped with a bypass line and drainage system. Maintenance activities could affect the uptime of the inline viscometer. This could become critical under field conditions, where problems with water treatment could translate into plugging of the viscometer filters, leading to erroneous measurements and eventual downtime for cleanup. Such problems grow with the number of devices in operation. Therefore, using a few viscometers is often considered a compromise that comes at the cost of less-effective viscosity monitoring. The authors address a solution to this problem wherein a machine-learning (ML) tool is proposed to augment viscosity measurements by calculating the viscosity using field data for the periods when no viscosity measurements are available.

Stokes-Einstein relation without hydrodynamic diameter in the TIP4P/Ice water model.

It is demonstrated that self-diffusion and shear viscosity data for the TIP4P/Ice water model reported recently [Baran et al., J. Chem. Phys. 158, 064503 (2023)] obey the microscopic version of the Stokes-Einstein relation without the hydrodynamic diameter.

Monitoring Viscosity of Polymer Products on the Reactor Tank Using IoT-based NodeMCU

Viscosity is one of the critical parameters for polymer products; thus, monitoring the viscosity level is very important to know during the production process and production results. The Polymer Company recently suffered heavy losses due to an explosion in one of its reactor engines, the R306 engine. The investigation results show that the viscosity of the polymer is one of the causes of the heavy workload of the machine, when the viscosity is checked manually. This research was conducted based on these conditions, and a viscosity monitoring device was designed for the 306-tank product. The design used QFD visualization for product design and UML for information system design. In this study, polymer viscosity was measured using the falling ball method with an Infrared Sensor E18-D80NK to obtain the viscosity of polymer products. Viscosity data are configured directly with the Internet of Things using the NodeMCU microcontroller. The design results show that the tool can monitor the viscosity in the tank and provide polymer viscosity information in real-time, thus facilitating decision-making and increasing productivity.

Temperature dependent volumetric, viscometric and conductance studies of barium chloride in aqueous solution of citric acid: an insight into molecular interactions

Abstract Alkaline earth metal salts and citric acid both play a vital role in our daily life in terms of biological importance, so in this regard, in the present study, we calculated density, speed of sound, conductance and viscosity of barium chloride (BaCl2) in concentration range (0.01–0.12 mol kg−1) in a binary solution of 0.01 mol kg−1 citric acid in water (CA + H2O) at temperatures between 303.15 and 318.15 K with gap of 5 K. The various parameters like apparent molar volume ϕ v , limiting apparent molar volume ϕ v o , transfer volume Δ tr ϕ v o , and partial molar volume expansibilities Φ E o ${{\Phi }}_{E}^{o}$ were calculated using density data. Viscosity data has been applied to calculate relative viscosity and Jones Dole coefficient A and B. Other parameters like Molar conductance (Λ m ), Λ o m and Λ o m η o have also been calculated using conductance data. All these parameters show strong evidences of various molecular interactions in terms of ion–solvent and solute–solute interactions. The ion–solvent interactions were supported by isobaric thermal expansion coefficient α o . Structure maker/breaker behaviour is explained by Hepler’s constant ((d 2 ϕ v o /dT 2 ) p ), temperature coefficient of B ( d B / d T $dB/dT$ ) and Walden product’s temperature coefficient (d(Λ o m η o )/dT). Further these molecular interactions support structure breaking potential of present studied system.

Modeling Flow and Transport in Saline Aquifers and Depleted Hydrocarbon Reservoirs for Hydrogen Energy Storage

Summary Hydrogen (H2) is an attractive energy carrier, and its true potential is in decarbonizing industries, such as for providing heat for buildings and being a reliable fuel for trains, buses, and heavy trucks. Industry is already making tremendous progress in cutting costs and improving the efficiency of hydrogen infrastructure. Currently, heating is primarily provided by using natural gas and transportation by gasoline with a large carbon footprint. Hydrogen has a similarly high energy density, but there are technical challenges preventing its large-scale use as an energy carrier. Underground geologic storage of hydrogen in porous media (aquifers and hydrocarbon reservoirs) could offer substantial storage capacity at low cost as well as buffer capacity to meet changing seasonal electricity demands or possible disruptions in power supply. Underground geologic storage must have adequate capacity and ability to inject/extract high volumes with a reliable caprock. A thorough study is essential for a large number of site surveys to locate and fully characterize the subsurface geological storage sites both onshore and offshore. An isothermal compositional reservoir simulator was used to evaluate hydrogen storage and withdrawal from saline aquifers and depleted oil/gas reservoirs. The phase behavior, fluid properties, and petrophysical models were all calibrated against published laboratory data for density, viscosity, relative permeability, and capillary pressure for a given site. History-matched dynamic models of two CO2 injection field projects in saline aquifers and one natural gas storage in a depleted oil reservoir were considered as hypothetical hydrogen seasonal storage sites. A wide range of working gas volume/cushion gas volume ratios was observed, meaning that careful optimization is required for a successful storage project. For the aquifer cases, the range was 0.292 to 1.883 and a range of 1.045 to 4.4 was observed for the depleted hydrocarbon reservoir scenarios. For the saline aquifer cases, a higher injection rate, longer injection/withdrawal (I/W) cycles, and the use of pump wells to control the hydrogen plume spreading were all beneficial for improving the working gas/cushion gas ratio and the working gas volume. Plume control was important for storage in the oil reservoir in which changes in the well length location and orientation showed high sensitivity in the working and cushion gas volumes. Sensitivities to the initial gas saturation in the depleted gas reservoir scenarios suggested that both cushion and working gas volumes increased with the initial gas saturation while the ratio of working to cushion gas volumes decreased with the initial gas saturation. Finally, when comparing the ratios of working to cushion gas volumes, it was the highest for the depleted oil reservoir, followed by the depleted gas reservoir, and the aquifer.

A Research on Rheological Behavior of Aqueous Solutions of Pomegranate Peel Powder

Determining the viscosity of pomegranate peel powder (PPP) can aid in product development, process optimization, quality control, ingredient interactions, and scientific research related to pomegranate peel-based products or formulations. Therefore, in this study, the rheological behavior of dried and ground pomegranate peel has been investigated. The apparent viscosities of pomegranate peel solutions prepared with distilled water are measured by a rotational viscometer. The viscosity of the pomegranate peel solution at each concentration is measured at shear rates varying between 2.64 s-1 and 22 s-1 at constant temperature (25 °C). When the effect of concentration on apparent viscosity has been examined, it is observed that the viscosity rises with increasing concentration at a constant shear rate. Among the rheological models studied, Power model provides a good fit for the experimental viscosity data of aqueous solutions of pomegranate peel powder at different concentrations. The consistency coefficient and the flow behavior index are calculated using the power law model and the solutions have been found to exhibit pseudoplastic behavior.

Thermodynamic modeling procedure for modeling viscosity of polymer solutions

In this work, the density and viscosity of five commonly used polymer aqueous solutions with a concentration range of 1–35 wt%, including polyvinylpyrrolidone (PVP) K25, PVP K30, PVP K90, polyethylene glycol (PEG) 6000 and hydroxypropyl methyl cellulose (HPMC), were determined at 293.15–313.15 K. The viscosity data were modeled by Simplified-Eyring-NRTL, Eyring-PC-SAFT and Simplified-Eyring-PC-SAFT models. Based on the correlation between the viscosity and the surface area fraction of solute and solvent, the Theta-Eyring-PC-SAFT model was proposed. The model had the best fitting effect on the viscosity data of PEG, PVP K25, PVP K30, PVP K90 and HPMC, and the correlation coefficients R2 were 0.9998, 0.9988, 0.9995, 0.9999 and 0.9999, respectively. In addition, the viscosity data of other systems in the literatures were also fitted, and the R2 values were all greater than 0.9900, which proved that the Theta-Eyring-PC-SAFT model was universal.

Application of the ramp test from a closed cavity rheometer to obtain the steady-state shear viscosity η(γ̇)

Abstract The steady-state shear viscosity η ( γ ̇ ) \eta (\dot{\gamma }) is required in controlling processing parameters for the extrusion processing of polymer melts. A new method, the so-called ramp test, is investigated in this study to obtain the steady-state shear viscosity with a closed cavity rheometer (CCR). To verify the method and the accuracy of the CCR data, three commercial polyolefin polymers, a low-density polyethylene (LDPE), a linear low-density polyethylene (LLDPE), and a polybutadiene (PBD), were used as model systems. Measurements of the magnitude of the complex viscosity ∣ η ⁎ ( ω ) ∣ | {\eta }^{\ast }(\omega )| were compared with the steady-state shear viscosity data obtained by capillary rheometer and CCR. Further, time–temperature superposition master curves of the magnitude of the complex viscosity and steady-state shear viscosity obtained by CCR were developed for LLDPE and PBD. The influence of the cavity sealing on the instrument’s accuracy to obtain the steady-state shear viscosity was investigated using the finite element method simulations. Thus, it was shown that the ramp test performed by CCR is a practical method to determine reliable and reproducible data of the steady-state shear viscosity within a wide range of temperatures (T = 50–180°C) for low and high viscous materials ( ∣ η ⁎ ( ω ) ∣ | {\eta }^{\ast }(\omega )| = 1.6–480 kPa s, M w = 144–375 kg mol−1).

Physico-chemical and biological studies of some Copper(I) complexes in binary mixtures of polar solvents at variable temperature

Physico-chemical parameters like, conductance, viscosity, volumetric, thermo acoustic, thermodynamics of viscous flow, were thoroughly evaluated from the experimentally obtained data of specific conductance, viscosity, density, and ultrasonic velocity. These parameters were evaluated for Copper(I) nitrate complexes in binary mixtures of polar solvents, Dimethylsulfoxide (DMSO), Pyridine (Py), and Nitromethane (NM) at variable temperatures (298 K-318 K) and at 1 atmospheric pressure. Ionic B values were evaluated using Jones-Dole equation to determine the extent of molecular interactions. From the measured viscosity, using Erying's transition state theory, the thermodynamic parameters of viscous flow such as Gibb's energy of activation (ΔG)*, enthalpy of activation (ΔH)*, and entropy of activation (ΔS)* were also evaluated. The thermodynamic function showed the values of ΔH* as positive for all electrolytes and ΔS* as negative. From the conductance data, the Energy of Activation (Ea) and ionic walden product (λoη) were evaluated and tabulated. Further, in order to discover more about the solute–solvent interactions, limiting apparent molar volume (ɸ˚v), Masson’s coefficient (Sv), partial molar expansibilities (ɸ˚E) and Hepler’s constant were also calculated from density and velocity data at variable temperatures. Limiting apparent molar volume ɸ˚v values for both binary mixtures were positive, indicating strong solute–solvent interactions. Thermo acoustical parameters like internal pressure (πi), Rao’s constant (Rm) and Wada’s constant (W) were also evaluated. The results from all the studies showed the possible solvation in DMSO + Py solvent mixture as compared to DMSO + NM system. Further, the copper(I) nitrate complexes with bioactive ligands were tested against Gram positive strains (S mutans MTCC 497 and S aureus MTCC 7443), Gram negative strains (S enteric MTCC 164 and P aeruginosa MTCC 4673) and fungus (A parasiticus NCIM 696, Candida albicans MTCC 183 and A niger NCIM 501). The zone of inhibition was also measured for the complexes. All the complexes with potential bioactive ligand containing Nitrogen and Sulphur atom bonded to central copper atom showed antibacterial and antifungal activity.

Thermophysical properties of 2-amino-2-methylpropan-1-ol + alkanol mixtures: Investigation of molecular interactions by insight of FT-IR spectroscopy

We report the experimental data of dynamic viscosity (η) and ultrasonic speed (u) for 2-amino-2-methylpropan-1-ol (AMP) (1) + alkanol (C1-C3) (2) at T = (298.15–318.15) K and 0.1 MPa pressure. The derived excess (or deviation in) properties like dynamic viscosity (Δη), speed of sound (Δu) and excess isentropic compressibility (κSE) were regressed through Redlich-Kister polynomial equation. The Δη values were analyzed in terms of an Ab-initio approach, to study the intermolecular interactions between the binary components. Our analysis indicated that compared to propanol, methanol and ethanol interact strongly with AMP and 2-propanol exhibited the weakest interactions with AMP owing to steric hindrance by branched propyl group. In addition, viscosity (η) values and ultrasonic speed (u) data were analyzed using the various thermodynamic models/correlations that agreed well with our experimental data. Furthermore, we analyzed the FT-IR spectra of pure components and their binaries and observed prevailing hydrogen bonding interactions between the N-atom and OH-group of AMP with the OH-group of alkanol. Our findings highlight the great bonding capability of AMP with lower alkanol due to its small size and linear shape and can provide information on designing effective binary mixtures (blended) solvents based on AMP for CO2 absorption.

Modeling the viscosity of ionic liquids using combined friction theory with perturbed hard-chain equation of state and neural network approaches

Fast and accurate prediction and correlation of thermophysical properties are always important concerns for researchers and engineers. This work is the extension of our earlier friction theory (FT)-based approach for estimating the dynamic viscosities of pure ionic liquids using a perturbed hard-chain equation of state. The model used three molecular parameters along with 5 correlation coefficients in the friction terms. The correlation coefficients were obtained using 167 data points at 0.1 MPa with an average absolute deviation (AAD) of 0.61 % and then used to predict the viscosity values at higher pressures. Using the FT-based model, 2907 experimental viscosity data for 20 pure ILs were predicted. The calculations were carried out in 273–373 K range and pressures up to 298.9 MPa for 2907 data points with an AAD of 2.63 %. The present FT-based model was not able to accurately predict the viscosities of ILs outside the temperature range used for the fit procedure. Also, comparing the precision of our FT-based model with two rough-hard-sphere theory-based models of Hosseini et al. and Hossain-Teja as well as the group-contribution method led to AADs of 2.46 % (for 2664 data points), 2.65 % (for 1605 data points), 3.25 % (for 890 data points), and 7.73 % (for 2558 data points, respectively. Viscosities of several mixtures of IL + IL type were also correlated using the present model along with some simple combining equations and a binary interaction parameter as well. The AAD of the calculated viscosities from the experimental ones was found to be 5.10 % for 960 data points examined. In addition, a neural network was trained on 3074 data points to represent the viscosity of studied pure ILs. The artificial neural network (ANN) structure utilized two layers, four input parameters, and 13 neurons for each layer. This specific structure of ANN was carefully designed to ensure an optimal performance in predicting the viscosity of ILs. The overall AAD was obtained 1.44 %.

Effect of ethanol on the density and viscosity of choline chloride/urea eutectic system

The densities and viscosities of choline chloride/urea deep eutectic solvents (DESs) at molar ratios of 1:1.5, 1:2, and 1:2.5 (abbreviated as [ChCl][Urea]1.5, [ChCl][Urea]2 and [ChCl][Urea]2.5) were measured in this work. In addition, the effects of ethanol on the density and viscosity of choline choloride/urea DESs were also investigated. The experimental density and viscosity data were obtained from 303.15 K to 323.15 K at atmospheric pressure. The measurements were carried out using digital vibrating U-tube densimeter and Ubbelohde capillary viscometer. The Jouyban-Acree model was used to correlate the experimental density and viscosity data. In addition, for comparison purpose, the viscosity model based on the preferential solution theory was also used for the viscosity correlation. The excess molar volumes and viscosity deviations of the studied mixtures were calculated from the experimental data, and the results were analyzed. The Redlich–Kister equation was used to correlate the excess molar volumes and viscosity deviations of the ethanol/[ChCl][Urea]x mixtures.