Relative Viscosity Data Research Articles

Ghost Red Blood Cells For Enhanced Particle Detection With Defocusing PTV In Microcirculation Experiments

Particle tracking of rigid fluorescent particles in microcirculation environments is often found to be difficult, since the presence of red blood cells (RBCs) at physiologically relevant conditions (i.e., hematocrit) masks the particle images. In turn, making particle detection challenging. To overcome this difficulty, we propose to use ghost RBCs for enhanced particle detection. These are quasi-transparent RBCs obtained by removing the hemoglobin from normal RBCs. To understand whether the ghost RBCs can improve the particle detection, we performed defocusing particle tracking measurements with the general defocusing particle tracking (GDPT) method of the rigid fluorescent particles in normal and ghost RBC flows. The measurements were performed at physiological relevant hematocrit and for three different flow rates. From the three-dimensional particle trajectories, we evaluated the correlation coefficient from the GDPT evaluations and compared the fluid dynamic behavior of the two types of cells. Overall, the results show that ghost RBCs are an attractive solution for this type of experiments, since they improve the correlation coefficients up to values similar to cell-free experiments, while exhibiting a fluid dynamic behavior similar to normal RBCs i.e., in terms of velocity and relative viscosity data.

Recent Progress in the Viscosity Modeling of Concentrated Suspensions of Unimodal Hard Spheres

The viscosity models for concentrated suspensions of unimodal hard spheres published in the twenty-first century are reviewed, compared, and evaluated using a large pool of available experimental data. The Pal viscosity model for unimodal suspensions is the best available model in that the predictions of this model agree very well with the low (zero)-shear experimental relative viscosity data for coarse suspensions, nanosuspensions, and coarse suspensions thickened by starch nanoparticles. The average percentage error in model predictions is less than 6.5%. Finally, the viscous behavior of concentrated multimodal suspensions is simulated using the Pal model for unimodal suspensions.

Advances in the modelling of concentration-dependent relative viscosity data for nanofluids by introducing the Dispersion Factor

The viscosity ratio (relative viscosity) of a nanofluid to its base liquid is related to the nanoparticle volume fraction by various developed theoretical and empirical equations. However, the theoretical framework used up to now is often inadequate for modelling experimental data. Now, a new parameter denoted as the Dispersion Factor (DF) is proposed to advance the accurate modelling of relative viscosities of nanofluids dependent on nanoparticle volume fraction. Literature data of TiO2, γ-Al2O3and SiO2nanofluids have been selected and subjected to our new theoretical treatment using the Chen equation adapted with the Dispersion Factor to model the relative viscosity in relation to the nanoparticle volume fractions.A much better agreement with the experimental data has been obtained. The value of DF that is identified by the mathematical modelling of relative viscosity data reflects the comprehensive effect of particle size, shape and chemical composition on the interactions between the nanoparticle and the base liquid on the one hand, and solvated nanoparticle and nanoparticle interactions on the other hand. The DF parameter may present a possible tool that can be used to tailor and tune the nanofluid design to meet specific application requirements.

Structuring natural deep eutectic solvents with epoxidised lignin-enriched residues: a green alternative to petroleum-based thickened formulations

• Natural Deep Eutectic Solvents (NADESs) were used as material base to obtain novel structuring materials based on lignin. • A crosslinked microstructural network was promoted by NADESs-epoxy-modified lignin chemical interactions. • The NADESs chemical nature showed a noticeable effect on the rheological properties of final structuring formulations. • The significant hydroxyl value of NADESs enabled the tunability of the ensuing formulations’ macroscopic properties. Natural deep eutectic solvents (NADESs) differing in the number of hydroxyl groups in the hydrogen bond donor (HBD) compound were investigated for usage as a matrix base in reactions involving a lignin-enriched fraction. NADESs were prepared by mixing citric acid with different HBDs (glycerol, xylitol, and sucrose). In addition, waste lignocellulose was epoxidised for use as a thickening agent for NADESs by promoting chemical crosslinking between the HBD hydroxyl groups and the epoxy rings of the lignocellulosic material. Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and thermogravimetric analysis were used to verify the reaction between NADES and the epoxidised lignin-rich material. In addition, full rheological characterisation was performed to evaluate the effects of the viscosity of NADESs and lignin-enriched residue concentration. A heating process was applied to determine the influence of water on the viscoelastic properties of the final products. The chemical interaction between NADESs and epoxidised lignocellulose was successfully achieved, resulting in various rheological responses, from liquid-like to gel-like, depending on the HBD compound comprising NADESs and the lignin concentration. The higher the number of hydroxyl groups in the HBD, the higher was the viscosity of the lignin-structured NADESs. An analysis of the relative viscosity data reveals that the epoxidised ligninocellulose residue exerts a similar structuring role in the three different NADESs.

Elucidation of Molecular Interactions of Non-Steroidal Anti-Inflammatory Drug Diclofenac Potassium in Aqueous and Aqueous Urea Solutions: Acoustic and Viscometric Approach

In this work, the physicochemical approach is proposed to reproduce the ultrasonic velocity and viscosity of diclofenac potassium over a range of temperature and concentration in aqueous and aqueous solutions of urea. Ultrasonic velocity (U) is measured at 298.15 K only. Using U values acoustic parameters like apparent molar compressibility (K_(s,ɸ)), isentropic compressibility (K_s), molar compressibility (W), acoustic impedance (Z), internal pressure (π_i), free volume (V_f), relative association (R_A), molar sound velocity (R) and free length (〖 L〗_f) have been evaluated. The relative viscosity data are analyzed at (298.15- 313.15) K using Jones-Dole relation and A_F and B_J coefficients are derived and discussed. Using the viscosity data Gibbs free energy of activation of viscous flow per mole of the solvent〖 ∆μ〗_1^(0*)And of solute 〖∆μ〗_2^(0*) were obtained. The results were discussed in terms of solute-solute and solute-solvent interactions in the studied systems.

Heat transfer nanofluids for trigeneration systems: fabrication and experimental investigation of viscosity at below-ambient temperatures

• Manufacture of graphene/MWCNT heat transfer nanofluids for CCHP systems. • The spectrum of temperatures ranged from − 10 ∘ C to 20 ∘ C. • Dissimilarity analysis using the two-sample variation of the Kolmogorov-Smirnov test. • Analysis of the effect of the nanoparticle type. • Relative apparent viscosity data were compared with five classical models. A new generation of energy-efficient buildings has emerged with the development of trigeneration technology (simultaneous production of heating, refrigeration and electric power). The operation of trigeneration systems requires working fluids (such as refrigerant for chillers), lubricants as well as heat transfer fluids (refrigeration secondary fluids and prime-mover coolants). Likewise, the dispersion of solid nanoparticles of promising materials such as graphene and MWCNT can potentially enhance the thermal conductivity of heat transfer fluids. However, pressure drop increases due to enhanced viscosity, which cannot be overlooked. In the present work, three graphene/MWCNT-heat transfer nanofluids were synthesized, and the temperature dependence of viscosity at below-ambient temperatures ( − 10 to 20 ∘ C) was experimentally investigated. This effect was analyzed using the two-sample variation of the Kolmogorov-Smirnov test. The nanofluids highest KS-dissimilarities occurred from 19.5 to 20 ∘ C and the empirical cumulative distribution functions had followed a linear profile. The KS-test was extended to analyze the effect of the nanoparticle type on nanofluids which have been synthesized with the same base fluid. However, no significant KS-dissimilarity was encountered. The relative viscosity followed a linear monotonic increase for all samples. Predictions provided by five classical models had underestimated the present data. Maron and Pierce’s equation presented the lowest error.

Cold start analysis of an engine coolant-MWCNT nanofluid: Synthesis and viscosity behavior under shear stress

During cold start of internal combustion engines, coolant temperature, and thermal conductivity are key parameters in the heat transfer processes that ultimately affect pollutant emissions and engine performance. Hereupon the use of coolants with suspended nanoparticles, to enhance thermal conductivity, emerged as a promising technology. However, for Newtonian materials, viscosity also increases with nanoparticle concentration. To overcome increased pumping power, the use of non-Newtonian nanofluids makes such application potentially feasible, specifically for shear-thinning materials, in which a higher shear rate leads to reducing shear viscosity due to higher shear stress. Accordingly, a nanofluid, suitable for engine cooling (0.2 wt.% MWCNT-engine coolant/distilled water 30/70 v/v%), was here fabricated and mapped. Shear rate and temperature were varied, with focus on cold start investigation. Shear thinning and shear thickening regions were mapped according to the shear rate levels, for each temperature considered. The nanofluid behaved as shear-thinning material for the entire range of temperatures (−10°C–25°C). Above shear rates of 500 s−1 and flow curves with temperatures below −5°C, a prominent shear thickening behavior was observed. Additionally, the relative apparent viscosity data were compared with four classical models. Regarding the curve fitting parameters of a modified Herschel-Bulkley equation, above 0°C, the apparent yield stress, [Formula: see text], was invariant with temperature. Besides, for the temperature range from 0°C to 20°C, the flow index remained approximately constant. For temperatures above −5°C, infinite-shear-rate viscosity and consistency index presented a linear decrease and a third-degree polynomial-like behavior, respectively.

Volumetric properties, viscosity coefficients and aggregation behaviour of DBU-acetate protic ionic liquid in molecular solvents

The density, viscosity and conductivity of binary mixtures of 1,8-diazabicyclo [5.4.0] undec-7-en-8-ium acetate [DBUH][OAc] protic ionic liquid (PIL) with water, ethanol and acetonitrile in the concentration range of (~0.02 to ~1.0) mol·kg−1 were measured at 298.15 K. Apparent molar volumes (φV) has been obtained for aqueous and non-aqueous solutions of [DBUH][OAc] using experimental density data. The concentration dependent φV data were analyzed using Redlich-Mayer equation to estimate limiting apparent molar volume (φV0) and deviation parameters (BV and DV). The relative viscosity data of [DBUH][OAc] solutions were correlated with Jones–Dole equation for obtaining viscosity A and B coefficients. Specific conductivity data of studied PIL+ solvent mixtures were fitted using Carpena's method to evaluate critical aggregation concentration (CAC). The CAC is further used to estimate standard Gibbs energy of aggregation. From studied parameters it has been observed that PIL-water and PIL-ethanol interactions are stronger than that of PIL-acetonitrile interactions. The results are discussed in terms of effect of dielectric constant, hydrogen bonding abilities of solvents on ion-solvent, ion-ion interactions, and on aggregation behaviour of DBU-acetate.

Studies of Volumetric and Viscosity Properties in Aqueous Solutions of Imidazolium Based Ionic Liquids at Different Temperatures and at Ambient Pressure

The ionic liquids (ILs) 1,3-dimethyl imidazolium methyl sulfate [MIm][MeSO4] and 1-ethyl-3-methyl imidazolium ethyl sulfate [EMIm][EtSO4] have been synthesized and characterized by 1H NMR, 13C NMR, mass spectrometry, TGA and DSC methods. The densities and viscosities of binary aqueous solutions of [MIm][MeSO4] (0.02458 to 0.18922 mol·kg−1) and [EMIm][EtSO4] (0.01044 to 0.21261 mol·kg−1) are reported at (293.15, 298.15 and 303.15) K and at ambient pressure. Apparent and partial molar volumes of the studied ILs are calculated at the studied concentrations. The limiting partial molar volumes of the studied ILs were obtained using an appropriate extrapolation method. The limiting apparent molar expansivity values at 298.15 K are also obtained. The relative viscosity data are analyzed by applying the Jones–Dole equation and Vand’s equations. Positive viscosity A and B coefficients were observed for both studied ILs, while the D coefficients were also found to be necessary, showing specific behavior depending upon the solute–solute interactions. Calculations of the B coefficients for anions are reported. The application of Vand’s equation to the viscosity data enabled us to calculate the Einstein–Simha factor (ν) and particle interaction coefficient ( $$Q$$ ) for the ion-pairs. The calculated ν values are found to be less than Einstein’s value of 2.5. The results are discussed from the points of view of the water structure making effect, solute–solvent hydrogen bond interaction and the presence of hydrophobic interaction.

Volumetric, viscometric and molecular simulation studies of glycine in aqueous sodium sulphate solutions at different temperatures

The densities and viscosities of Glycine in five aqueous solutions of Sodium Sulphate, were measured in the temperature range from 283.15 to 308.15 K at intervals of 5 K, using a vibrating U-tube densimeter Anton Paar DMA 5000 and the Automatic Microviscosimeter AMVn, respectively. The measured densities were used to calculate the limit-apparent molar volume (Vϕ0), limit-transfer molar volume (ΔtrVφ0)and hydration number (nh). The partial volumes at infinite dilution of the glycine in aqueous solution of sodium sulfate were evaluated through extrapolation at each temperature. The behavior of ΔtrVϕ0 was interpreted in terms of solute–solvent interactions on the basis of the cosphere-overlap model. The hydration numbers were positive and interpreted in terms of dehydration and electrostriction effects. The relative viscosity data were adjusted by least-squares for obtain the Jones-Dole equation coefficients A, B and D. To accompany the experimental results, a series of small molecular complexes simulating the interactions present in the glycine + water/sodium sulfate systems were modeled by the Density Functional Theory with the basis function 6-31G(d). From viscosity dates, the activation parameters of the viscous flow (free molar energy of Gibbs ΔG≠, enthalpy ΔH≠, and entropy ΔS≠) were evaluated. The temperature dependence of the partial molar volume at infinite dilution and the viscosity B coefficient were discussed in terms of the dominant interactions in solution; it was found that the glycine has a making effect in the structure of the solvent, and at infinite dilution ion-solvent interactions are dominant between NH3+ and COO− groups of the amino acid with Na+ and SO42− ions. From the theoretical point of view, the complexes studied turned out to be stable and represent a good approximation to rationalize the intermolecular interactions that occur in glycine + water/sodium sulphate mixtures.

Effect of methanol on the surface tension and viscosity of sodiumdodecyl sulfate (SDS) in aqueous medium at 298.15–323.15 K

The surface tension and viscosity of sodiumdodecyl sulfate (SDS) in water and in 0.10, 0.20, 0.30 and 0.40 volume fractions of methanol in water at 298.15 K, 308.15 K, 318.15 K and 323.15 K are measured. The critical micelle concentrations (CMCs) of the solutions are determined from both the surface tension and viscosity. The critical micelle concentrations (CMC) of SDS in water as well as in methanol-water mixture are found to increase with increase in temperature. The CMC of SDS increases with the addition of methanol. The surface properties, such as the surface excess concentration Гmax, minimum surface area Amin, surface pressure πcmc and packing parameter P are calculated from the surface tension data. Viscosity B coefficients of the SDS solutions are calculated using the relative viscosity data.

Effect of temperature on the partial molar volumes, partial molar compressibility and viscosity B-coefficients of DL-4-aminobutyric acid in water and in aqueous sodium chloride solutions

Density, sound velocity and viscosity of DL-4-aminobutyric acid (GABA) in water and in aqueous sodium chloride solutions have been measured at (293.15, 298.15, 303.15, 308.15 and 313.15)K. The apparent molar volumes and the apparent molar compressibilities were calculated at each temperature from the experimental density and sound velocity data. Limiting values at infinite dilution of the partial molar volumes and the partial molar compressibilities of GABA in water and in aqueous sodium chloride solutions were determined through extrapolation at each temperature. The relative viscosity data were adjusted by a least-squares method to a second order equation as proposed by Tsangaris-Martin to obtain the viscosity B coefficients. The influence of temperature on the behaviour of viscosity and the volumetric properties is discussed in terms of molecular interactions.The results confirm that hydrophilic hydration is predominant for GABA in aqueous solution. The addition of NaCl leads to an increase of the partial molar properties at infinite dilution and the viscosity B-coefficients, suggesting that the sodium and the chloride ions interact directly with the zwitterion, reducing the electrostriction of water molecules.

Issue Highlights

The Canadian Journal of Chemical EngineeringVolume 95, Issue 8 p. 1431-1431 Issue HighlightsFree Access Issue Highlights First published: 06 July 2017 https://doi.org/10.1002/cjce.22919AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat 1449 The Role of Hydrophobic Properties in Ion Exchange Removal of Organic Compounds from Water Sonia Rahmani and Madjid Mohseni The removal of organic compounds from water by ion exchange resins involves the contribution of various phenomena. This work studies the removal efficiency of three organic compounds which possess similar charged group but contain different non-polar moieties. The greater removal of compounds with more hydrophobic nature indicates the importance of solute-solvent interactions. Hydrophobic compounds also compete with inorganic anions present in the water matrix. The rejection of hydrophobic moieties from water and thus a favourable positive entropy change in the system by their removal is a crucial driver for the adsorption of organics onto the resin.1 1463 Prediction of Spout Diameter in Gas-Solid Spouted Beds Using Factorial Design of Experiments Approach with the Aid of Advanced Optical Fibre Probe Muthanna Al-Dahhan, Shreekanta Aradhya and Haidar Taofeeq The spout diameter is considered an important hydrodynamic parameter in the design and operation of gas-solid spouted beds. Therefore, the impact of five operating and design variables (solid density, static bed height, particle diameter, superficial gas velocity, and inlet diameter) on the spout diameter have been studied in the present work. The experimental measurements were carried out in a gas-solid spouted bed of 0.152 m inside diameter by the means of advanced gas-solid optical ibre probe technique. The factorial design of the experiments method was applied on the experimental results to evaluate the effect of these variables on the spout diameter.2 1605 Viscosity-Concentration Relationships for Nanodispersions Based on Glass Transition Point Rajinder Pal Using free volume arguments, a simple model is developed for the zero-shear relative viscosity of nanodispersions taking into consideration the solvation and aggregation of nanoparticles. The zero-shear relative viscosity data of 16 sets of nanodispersions are found to collapse onto a single curve when the data are plotted as relative viscosity versus volume fraction of solvated nanoparticles. The zero-shear viscosity of nanodispersions diverges at the glass transition volume fraction of solvated nanoparticles of about 0.58. Above the glass transition concentration of solvated nanoparticles, the correlation of relative viscosity of nanodispersions is not successful.3 References 1 S. Rahmani, M. Mohseni, Can. J. Chem. Eng. 2017, 95, 1449. 2 M. Al-Dahhan, S. Aradhya, H. Taofeeq, Can. J. Chem. Eng. 2017, 95, 1463. 3 R. Pal, Can. J. Chem. Eng. 2017, 95, 1605. Volume95, Issue8August 2017Pages 1431-1431 ReferencesRelatedInformation

Modeling and Scaling of the Viscosity of Suspensions of Asphaltene Nanoaggregates

The scaling and modeling of the viscosity of suspensions of asphaltene nanoaggregates is carried out successfully taking into consideration the solvation and clustering of nanoaggragates, and the jamming of the suspension at the glass transition volume fraction of asphaltene nanoaggregates. The nanoaggregates of asphaltenes are modeled as solvated disk-shaped “core–shell” particles taking into account the most recent small-angle neutron scattering (SANS), small-angle X-ray scattering (SAXS), and solid-state 1H NMR studies available on the size and structure of asphaltene nanoaggregates. This work is an extension of our earlier studies on modeling of asphaltene suspensions where solvation of asphaltene nanoaggregates was not considered. A new mathematical model is developed for estimating the aspect ratio (ratio of thickness to diameter of particle) and the corresponding intrinsic viscosity of suspension of solvated disk-shaped asphaltene nanoaggregates using the experimental relative viscosity data of suspensions at low asphaltene concentrations. The solvation of asphaltene nanoaggregates is found to be significant. The intrinsic viscosity increases with the increase in the degree of solvation of nanoaggregates. At high concentrations of asphaltenes, clustering of solvated nanoaggregates dominates resulting in large viscosities. A new scaling law is discovered to scale the viscosity data of different asphaltene suspensions. According to the new scaling law, a unique correlation is obtained, independent of the type of asphaltene system, when the data are plotted as ( η r − 1 ) / [ η ] S versus ϕ S where η r is the relative viscosity of suspension, [ η ] S is the intrinsic viscosity of suspension of solvated nanoaggregates, and ϕ S is the volume fraction of solvated nanoaggregates. Twenty sets of experimental viscosity data on asphaltene suspensions gathered from different sources are used to verify and confirm the scaling law and the viscosity model proposed in this work. Based on the experimental data, the glass transition volume fraction of solvated asphaltene nanoaggregates where jamming of suspension, and hence divergence of viscosity, takes place is found to be approximately 0.4. The viscosity model proposed in this work can be used to predict the viscosity of a new asphaltene system over a broad range of asphaltene concentrations provided that the intrinsic viscosity of the suspension is obtained from viscosity measurements at very low asphaltene concentrations.

Viscosity‐concentration relationships for nanodispersions based on glass transition point

ABSTRACTThe theoretical background relevant to modelling of the viscous behaviour of nanodispersions (nanosuspensions and nanoemulsions) is discussed. Using free‐volume arguments, a simple model is developed to describe the viscous behaviour of nanodispersions. A large pool (16 sets) of available experimental data on the zero‐shear relative viscosity of nanodispersions is correlated on the basis of the effective volume fraction of solvated nanoparticles/nanodroplets. It is found that the experimental data can be successfully correlated using the volume fraction of solvated nanoparticles/nanodroplets only below the glass transition volume fraction of solvated nanoparticles/nanodroplets. The glass transition volume fraction of solvated nanoparticles/nanodroplets is about 0.58, which is in agreement with the value found in the literature. The experimental relative viscosity data of all sixteen sets of nanoemulsions and nanosuspensions collapse on to a single curve which is well described by the proposed model provided that the volume fraction of solvated nanoparticles/nanodroplets is below the glass transition value of 0.58. Above the glass transition volume fraction of 0.58, the correlation of relative viscosity on the basis of solvated volume fraction is not successful. Above the glass transition point, the nanodispersion is in an arrested (jammed) state and is expected to possess yield‐stress. Thus the concept of zero‐shear viscosity itself becomes unreliable and meaningless above the glass transition point.

Rheological properties of gas and water atomized 17-4PH stainless steel MIM feedstocks: Effect of powder shape and size

Influence of powder shape resulting from the fabrication route (gas or water atomization) together with the effect of mean particle size and solid loading on rheological properties of highly filled metal powder feedstocks was investigated as a key to processing of Metal Injection Molding (MIM) parts without voids and cracks. Eight 17-4PH gas or water atomized powders varying in the mean particle diameters from 3 to 20μm were admixed into paraffin wax/high density polyethylene (50/50) binder at powder loadings up to 70vol.%. The relative viscosity data obtained from capillary rheometer was fitted with rheological models to evaluate maximum loading along with the determination of the same parameter using time dependent torque measurement. It was found out that for coarse particles the processability in terms of rheological behavior is better in case of gas atomized powders in accordance with previous findings, but in case of fine powders, water atomized powders showed higher performance.

Viscosity coefficients of KCl, NaCl, NaI, KNO3, LiNO3, NaBPh4 and Bu4NI in water-rich binary mixtures containing propan-2-ol at 298.15 K

ABSTRACTViscosities of KCl, NaCl, NaI, KNO3, LiNO3, NaBPh4 and Bu4NI solutions (from ~0.01 M to ~0.05 M) in water (1) + propan-2-ol) (2) binary mixtures with mole fractions of propan-2-ol, x2 = 0.01, 0.02, 0.05, 0.075, 0.10 and 0.15, were determined at 298. 15 K. The relative viscosity data have been analysed and interpreted in terms of the Jones–Dole equation, ηr = A∙c1/2 + B∙c. The obtained results allowed to determine the values of B± coefficients for individual ions using the assumption about the equality . All the results presented in this article have been discussed in terms of ion–solvent interactions.

Modeling the Viscosity of Concentrated Nanoemulsions and Nanosuspensions

The modeling of the viscous behavior of nanoemulsions and nanosuspensions is discussed. The influences of the viscosity ratio, solvation and aggregation of nanodroplets and nanoparticles on the relative viscosity of nanofluids are considered. The relative viscosity of a nanofluid is strongly affected by solvation of nanoparticles. The scaling of the relative viscosity of nanoemulsions is successfully carried out using the volume fraction of the solvated nanodroplets. Four sets of experimental relative viscosity data of nanoemulsions consisting of different diameter nanodroplets (27.5 nm–205 nm) all collapse on a single unique curve when the data are scaled on the basis of the volume fraction of the solvated nanodroplets. A similar scaling is achieved using six sets of experimental relative viscosity data on nanosuspensions consisting of different diameter nanoparticles (29 nm–146 nm). A new modified version of the Oldroyd model is proposed to describe and predict the viscosity of nanofluids. The model takes into consideration the influences of the viscosity ratio, solvation and aggregation of nanoparticles/nanodroplets. The same model is applicable to both nanoemulsions and nanosuspensions as it includes the effect of the viscosity ratio (ratio of droplet viscosity to matrix viscosity) on the relative viscosity of nanofluids. More experimental work is needed on nanoemulsions to explore the effect of the viscosity ratio, especially at low values of the viscosity ratio.

Viscosity B-Coefficient for Sodium Chloride in Aqueous Mixtures of 1,4-Dioxane at Different Temperatures.

Viscosities of sodium chloride solutions in water-1,4-dioxane binary mixtures with mole fractions of 1,4-dioxane, x(D) = 0.05, 0.10, 0.15 and 0.20, in the temperature range from 278.15 to 318.15 K were determined. The relative viscosity data have been analyzed and interpreted in terms of the rearranged Jones-Dole equation, (η(r) - 1) - Ac(1/2) = Bc. The viscosity A-coefficients were calculated from Falkenhagen and Vernon theory by help of the literature limiting ionic conductivity data and B-coefficients were estimated from linear plots. All B-coefficients obtained for NaCl water-1,4-dioxane binary mixtures are positive at all temperatures. These data were compared with the data for NaCl in aqueous medium at different temperatures reported in literature. The ion-ion, ion-solvent and solvent -solvent interactions have been discussed.

Partial molar volumes and viscosities of aqueous hippuric acid solutions containing LiCl and MnCl2 · 4H2O at 303.15 K

Density (ρ) and viscosity (η) of aqueous hippuric acid (HA) solutions containing LiCl and MnCl2 · 4H2O have been studied at 303.15 K in order to understand volumetric and viscometric behavior of these systems. Apparent molar volume (φv) of salts were calculated from density data and fitted to Massons relation and partial molar volumes (φ v 0 ) at infinite dilution were determined. Relative viscosity data has been used to determine viscosity A and B coefficients using Jones-Dole relation. Partial molar volume and viscosity coefficients have been discussed in terms of ion-solvent interactions and overall structural fittings in solution.