Effect of Temperature and Nanoparticle Concentration on the Viscosity of Glycerine-water based SiO2 Nanofluids

Dynamic viscosity of SiO2/22nm nanofluids prepared in a glycerine-water (30:70 by volume) mixture base liquid, referred to as GW70, is measured experimentally. Nanofluids with concentrations of 0.2, 0.6, and 1.0 percent are produced, and viscosity measurements are carried out at temperatures ranging from 20 to 80 oC using a LVDV-2T model Brookfield Viscometer. The particle size and elemental composition of nanoparticles are determined using FESEM and EDX. XRD images confirm the SiO2 peaks in the crystalline structure. The rheology of nanofluids is influenced by the nanoparticle’s concentration. In the experimental temperature and concentration range, nanofluids show Newtonian behavior. The viscosity of nanofluids enhanced as particle concentration increased and reduced as temperature increased. For 1.0 percent vol. concentration at 20oC, the maximum viscosity value is achieved, and for 0.2 percent vol. concentration at 80oC, the lowest viscosity value is observed. The viscosity of the glycerine-water base fluid was also determined at 20, 40, 60, and 80 degrees Celsius. The viscosity ratio of nanofluids to the base liquid is found to be more than one for all the nanofluids. This viscosity data is useful to estimate HTC of glycerine-water-based silica nanofluids.

Viscosity of evolving magmas: a case study of the Glass House Mountains, Australia

The viscosity of the remelted rock compositions of the Glass House Mountains, SE Queensland, Australia, has been determined via micro-penetration in the high-viscosity regime (108–1013 Pa s). The heat capacity of these melts has also been determined from room temperature to above the glass transition. The combination of these two data sets allows the fitting of the viscosity data by the Adam-Gibbs equation using the configurational heat capacity Cpconf(Tg12) and configurational entropy Sconf(Tg12). The resulting fit parameters allow the robust extrapolation of the viscosity data to higher temperature and viscosities of 10–4 Pa s. This data can now be used in the discussion of the emplacement of the magmas of the plugs, laccoliths, sills and dykes that form the Glass House Mountains complex and the plate motion and the plume responsible for the volcano plugs. The large increase in viscosity of the evolving magma and the resulting decrease in discharge rate of the volcanic vents suggest that very little magma appeared as extrusive lavas or pyroclastic material and that the Glass House Mountains are mainly remnants of intrusive bodies exposed by erosion.

Elongational viscosity and brittle fracture of bidisperse blends of a high and several low molar mass polystyrenes

Elongational viscosity data of four well-characterized blends consisting of 10% mass fraction of monodisperse polystyrene PS-820k (molar mass of 820 kg/mol) and 90% matrix polystyrenes with a molar mass of 8.8, 23, 34, and 73 kg/mol, respectively, as reported by Shahid et al. Macromolecules 52: 2521–2530, 2019 are analyzed by the extended interchain pressure (EIP) model including the effects of finite chain extensibility and filament rupture. Except for the linear-viscoelastic contribution of the matrix, the elongational viscosity of the blends is mainly determined by the high molar mass component PS-820k at elongation rates when no stretching of the lower molar mass matrix chains is expected. The stretching of the long chains is shown to be widely independent of the molar mass of the matrix reaching from non-entangled oligomeric styrene (8.8 kg/mol) to well-entangled polystyrene (73kg/mol). Quantitative agreement between data and model can be obtained when taking the interaction of the long chains of PS-820k with the shorter matrix chains of PS-23k, PS-34k, and PS-73k into account. The interaction of long and short chains leads to additional entanglements along the long chains of PS-820k, which slow down relaxation of the long chains, as clearly seen in the linear-viscoelastic behavior. According to the EIP model, an increased number of entanglements also lead to enhanced interchain pressure, which limits maximal stretch. The reduced maximal stretch of the long chains due to entanglements of long chains with shorter matrix chains is quantified by introducing an effective polymer fraction of the long chains, which increases with the increasing length of the matrix chains resulting in the excellent agreement of experimental data and model predictions.

Evaluation of viscosity in binary mixtures of dimethyl sulphoxide at 298.15K

The viscosity of binary mixtures of dimethyl sulphoxide with different alcohols such as methanol, ethanol, 1-propanol, iso-propanol, 1-butanol, iso-butanol, tertiary butanol has been determined at 298.15K. The experimental values are compared with theoretical values evaluated by different theories. It is observed that for some theories, values are in agreement with the experimental values. Further, an attempt has been made to study the intermolecular interactions in studied solutions in terms of excess free energy of mixing, strength of interaction parameters and interaction energy. The viscosity data of pure liquids and their mixtures are needed to design various chemical processes where heat and mass transfer are important.

Molecular interaction investigation of some alkaline earth metal salts in aqueous citric acid at various temperatures by physiochemical studies

Densities, ultrasonic velocity, conductance and viscosity of some alkaline earth metal chlorides such as magnesium chloride (MgCl2) and calcium chloride (CaCl2) were calculated in the concentration range (0.01–0.12 mol kg−1) in 0.01 mol kg−1 aqueous solution of citric acid (CA + H2O) at four varying temperatures T 1 = 303.15 K, T 2 = 308.15 K, T 3 = 313.15 K and T 4 = 318.15 K. The parameters like apparent molar volume (ϕ v ), limiting apparent molar volume ( ϕ v o ${\phi }_{v}^{o}$ ) and transfer volume (Δtr ϕ v o ${\phi }_{v}^{o}$ ) were calculated from density data. Viscosity data have been employed to calculate Falkenhagen coefficient (A), Jone–Dole’s coefficient (B), relative viscosity (η r ), and relaxation time (τ) whereas limiting molar conductance ( Λ m o ${{\Lambda}}_{m}^{o}$ ) has been evaluated from conductance studies. Using these parameters, various type of interactions occurred in the molecules have been discussed. Values of Hepler’s constant (d 2 ϕ v o ${\phi }_{v}^{o}$ /dT 2) p , (dB/dT) and d( Λ m o ${{\Lambda}}_{m}^{o}$ η o )/dT suggests that both MgCl2 and CaCl2 behave as structure breaker in (CA + H2O) system. The positive value of transfer volume exclusively tells about solute–solvent interactions which further indicate that both metal chlorides distort the structure of water and act as structure breaker. These studies are helpful in understanding the nature of interactions occurs in biological systems as CA and metal salts are essential for normal functioning of body.

Thermo Acoustic Study of Salicylaldehyde in Carbon Tetra Chloride at 303.15K, 308.15K, 313.15K

Thermo-acoustic study in binary mixture of salicylaldehyde and carbon tetra chloride were reported at 303.15K, 308.15K, 313.15K. The molecular interaction have been carried out by computing various thermo acoustical parameters i.e. Intermolecular free length (Lf), Specific acoustic Impedance (Z), Molar Volume (Vm), Available Volume (Va), Isentropic compressibility (S) and other constant and the excess value of foresaid parameters have been evaluated by using ultrasonic velocity, density, viscosity data, the results of these parameters conclude the strength of molecular interaction. Keywords: Excess values of Salicylaldehyde, Acoustic Parameters, Molecular Interaction.

Recommended Values of the Viscosity in the Limit of Zero Density for R134a and Six Vapors of Aromatic Hydrocarbons as Well as of the Initial Density Dependence of Viscosity for R134a. Revisited from Experiment Between 297 K and 631 K

Previously published experimental viscosity data at low density, originally obtained using all-quartz oscillating-disk viscometers for R134a and six vapors of aromatic hydrocarbons in the temperature range between 297 K and 631 K at most, were re-evaluated after an improved re-calibration. The relative combined expanded ($$k=2$$ k = 2 ) uncertainty of the re-evaluated data are 0.2 % near room temperature and increases to 0.3 % at higher temperatures. The re-evaluated data for R134a as well as for the vapors of mesitylene, durene, diphenyl, fluorobenzene, chlorobenzene, and p-dichlorobenzene were arranged in approximately isothermal groups and converted into quasi-isothermal viscosity data using a first-order Taylor series in temperature. Then, the data for R134a were evaluated by means of a series expansion truncated at first order to obtain the zero density and initial density viscosity coefficients, $$\eta ^{(0)}$$ η ( 0 ) and $$\eta ^{(1)}$$ η ( 1 ) . For the six aromatic vapors, the Rainwater–Friend theory for the initial density dependence of the viscosity was used to derive $$\eta ^{(0)}$$ η ( 0 ) values. Finally, reliable $$\eta ^{(0)}$$ η ( 0 ) and also $$\eta ^{(1)}$$ η ( 1 ) values for R134a were selected as reference values in the measured temperature range to be applied when generating a new viscosity formulation.

Prediction of High-Pressure/High-Temperature Rheological Properties of Drilling Fluids from the Viscosity Data Measured on a Coaxial Cylinder Viscometer

Summary Determining the rheology of drilling fluid under subsurface conditions—that is, pressure > 103.4 MPa (15,000 psi) and temperature > 450 K (350°F)—is very important for safe and trouble-free drilling operations of high-pressure/high-temperature (HP/HT) wells. As the severity of HP/HT wells increases, it is challenging to measure downhole rheology accurately. In the absence of rheology measurement tools under HP/HT conditions, it is essential to develop an accurate rheological model under extreme conditions. In this study, temperature- and pressure-dependence rheology of drilling fluids [i.e., shear viscosity, apparent viscosity (AV), and plastic viscosity (PV)] are predicted at HP/HT conditions using the fundamental momentum transport mechanism (i.e., kinetic theory) of liquids. Drilling fluid properties (e.g., density, thermal decomposition temperature, and isothermal compressibility), and Fann® 35 Viscometer (Fann Instrument Corporation, Houston, USA) readings at surface conditions, are the only input parameters for the proposed HP/HT shear viscosity model. The proposed model has been tested using 26 different types of HP/HT drilling fluids, including water, formate, oil, and synthetic oil as base fluids. The detailed error and the sensitivity analysis have been performed to demonstrate the accuracy of the proposed model and yield comparative results. The proposed model is quite simple and may be applied to accurately predict the rheology of numerous drilling fluids. In the absence of subsurface rheology under HP/HT conditions, the proposed viscosity model may be used as a reliable soft-sensor tool for the online monitoring and control of rheology under downhole conditions while drilling HP/HT wells.

Modelling the Diffusion Coefficients of Dilute Gaseous Solutes in Hydrocarbon Liquids

In this work, we present a model, based on rough hard-sphere theory, for the tracer diffusion coefficients of gaseous solutes in non-polar liquids. This work extends an earlier model developed specifically for carbon dioxide in hydrocarbon liquids and establishes a general correlation for gaseous solutes in non-polar liquids. The solutes considered were light hydrocarbons, carbon dioxide, nitrogen and argon, while the solvents were all hydrocarbon liquids. Application of the model requires knowledge of the temperature-dependent molar core volumes of the solute and solvent, which can be determined from pure-component viscosity data, and a temperature-independent roughness factor which can be determined from a single diffusion coefficient measurement in the system of interest. The new model was found to correlate the experimental data with an average absolute relative deviation of 2.7 %. The model also successfully represents computer-simulation data for tracer diffusion coefficients of hard-sphere mixtures and reduces to the expected form for self-diffusion when the solute and solvent become identical.

Viscometric Study of n-Hexylammonium and n-Octylammonium perchlorates in Binary Non-Aqueous Solvents Probed by a Physicochemical Approach in the Temperature Ranging 298 - 328K at Atmospheric Pressure

Viscosity data were measured for n-hexyl ammonium perchlorate (C6H13NH3ClO4)(HAP) and n-octylammonium perchlorate (C8H17NH3ClO4) (OAP) in acetonitrile (AN), dimethylsulfoxide (DMSO) and their binary mixtures containing 0, 20, 40, 60, 80 and 100 mol%DMSO at 298, 308, 318 and 328 K in the concentration range 60-350×10-4 mol.dm-3. The data was further examined to evaluate ion-ion and ion-solvent interactions in terms of the Aand B coefficients of the Jones-Dole equation respectively. A and B coefficients for the studied electrolytes came out be to be positive throughout the whole composition range. However, smaller values of A as compare to B reveal the dominance of ion-solvent interaction over ion-ion interactions especially at 60 mol% DMSO in AN-DMSO mixtures. Thermodynamic parameters like free energy, enthalpy and entropy change of activation of the viscous flow have also been evaluated by using Erying transition state theory.