Showing papers on "Viscometer published in 2010"
TL;DR: In this paper, the thermal conductivity and viscosity of deionized water nanofluid is measured and studied for temperatures between 50°C and 90°C using the transient hot-wire apparatus and the Cannon-Fenske viscometer.
Abstract: This article presents an experimental investigation where the thermal conductivity and viscosity of silver-deionized water nanofluid is measured and studied. The mixture consists of silver nanoparticles of 0.3, 0.6, and 0.9% of volume concentrations and studied for temperatures between 50°C and 90°C. The transient hot-wire apparatus and Cannon-Fenske viscometer are used to measure the thermal conductivity and kinematic viscosity of nanofluid, respectively. The thermal conductivity increases with the increase in temperature and particle concentrations. A minimum and maximum enhancement of 27% at 0.3 vol% and 80% at 0.9 vol% are observed at an average temperature of 70°C. The viscosity decreases with the increase in temperature and increases with the increase in particle concentrations. The effect of Brownian motion and thermophoresis on the thermo-physical properties is discussed. Thus, an experimental correlation for thermal conductivity and viscosity, which relates the volume concentration and t...
264 citations
TL;DR: In this article, the effect of molecular weight, storage life, presence of electrolyte, and particle size of chitosan on its viscosity was investigated, and the chelation property of CHITOSAN was also evaluated.
Abstract: Chitosan, a versatile biopolymer, finds numerous applications in textile processing unit operations such as preparation, dyeing, printing, and finishing. However, the accessibility of this biopolymer by the textile material depends on the viscosity of its solution which in turn is a function of its molecular weight. In this work, therefore, the effect of molecular weight, storage life, presence of electrolyte, and particle size of chitosan on its viscosity was investigated. Chitosan of different molecular weights was synthesized by nitrous acid hydrolysis of parent chitosan solution. The synthesized low molecular weight products were analysed by FTIR spectroscopy. Chitosan of nanoconfiguration was prepared by Ionotropic gelation method and characterized by particle size analyzer. The viscosity of different chitosan solutions was determined using Ubbelohde capillary viscometer. As an extension to this study, the chelation property of chitosan was also evaluated.
107 citations
TL;DR: Reduced viscosity, kinetics parameters and molecular characteristics led UDMA-based composites to elevated conversion and relatively lower PS at lower TEGDMA contents, compared to B/T composites.
84 citations
TL;DR: In this article, the zero shear viscosity of two kinds of polysulfone (PSF) casting solutions and the morphology and permeability of their membranes prepared via the phase-inversion process were investigated.
76 citations
TL;DR: It could be concluded that the microfluidic viscometer developed in this study is capable of measuring viscosity of both Newtonian fluid (SDS solution) and non-Newtonian fluids (whole blood) with a relatively high accuracy in a continuous and near real-time fashion.
Abstract: A high-precision microfluidic viscometer with a microfluidic channel array composed of 100 indicating channels is demonstrated in this study. The relative viscosity of the sample fluid could be measured by simply counting the number of the indicating channels occupied by the sample and the reference fluids. Using lumped parameter modeling, an analytical solution of the relative viscosity is derived. In order to evaluate the performance of the developed microfluidic viscometer, the viscosity values obtained by the microfluidic viscometer are compared with the ones obtained by a conventional viscometer. In Newtonian fluid (sodium dodecyl sulfate [SDS] solution) tests, the normalized differences in the viscosities measured by two methods are less than 2.5%. In non-Newtonian fluid (whole blood, 45% hematocrit) tests at various shear rates, the viscosities measured by two methods are evaluated by a regression analysis via power law (). The k values for both the microfluidic viscometer and the conventional viscometer are 12.953 and 13.175, respectively; the n values are 0.797 and 0.807, respectively. The normalized differences in two parameters measured by two methods are less than 2%. Thus, it could be concluded that the microfluidic viscometer developed in this study is capable of measuring viscosity of both Newtonian fluid (SDS solution) and non-Newtonian fluid (whole blood) with a relatively high accuracy in a continuous and near real-time fashion. Furthermore, the viscometer could be potentially employed in cardiopulmonary bypass procedures by continuously monitoring viscosity changes due to blood damages and hemodilution.
61 citations
TL;DR: In this paper, a three-dimensional simulation and experimental investigation of polymer rheology in a miniature injection molding process is presented, where the simulation results are in good conformity and the strength of FLUENT 6.3 in handling injection mold filling problems is proved to be excellent.
58 citations
TL;DR: In this article, the conformations of poly(allylamine hydrochloride) (PAH) molecules in electrolyte solutions were determined experimentally for various pH and ionic strength by dynamic light scattering (DLS), microelectrophoresis and dynamic viscosity measurements.
58 citations
TL;DR: In this article, the effects of rare earth elements on the behavior of soda-lime-silicate glass were investigated by the rotating crucible viscometer and dilatometry, the melting temperature and activation energy for viscous flow of the studied melt were derived on the basis of Arrhenius equation.
55 citations
TL;DR: Results show reduced viscosity with dose over the range 0-4 Gy, the latter covering the dose regime of interest in fractionated radiotherapy, and shows agreement with previous Raman microspectrometry findings by others.
53 citations
TL;DR: In this paper, a transient hot-wire apparatus is used for measuring the thermal conductivity of nanofluids and a Cannon-Fenske viscometer is used to measure the kinematic viscosity of nanophotonics.
Abstract: This article presents the measurement of thermal conductivity and viscosity of nanofluids experimentally. Silver nanoparticles dispersed in water with volume concentrations of 0.3, 0.4, 0.6, 0.8, 0.9, and 1.2 vol% are used in the present study. A transient hot-wire apparatus is used for measuring the thermal conductivity of nanofluids and a Cannon-Fenske viscometer is used to measure the kinematic viscosity of nanofluids. The data are collected for temperatures ranging from 50 to 90°C. The results have shown an increase in the measured thermal conductivity and viscosity of nanofluids as the particle concentrations increase, and the values are higher than the values of the base liquids. The minimum enhancement of 27% for 0.3 vol% and a maximum enhancement of 115% for 1.2 vol% are observed at an average temperature of 70°C when compared with pure water for the same temperature. Further, the thermal conductivity of nanofluids increases with the increase in nanofluid temperatures and, conversely, the viscosit...
44 citations
TL;DR: Viscosity trends in pretreated corn stover slurries undergoing enzymatic saccharification were characterized for a range of initial insoluble solids concentrations from 10% to 25% and correlated with total glucose released and changes in insolublesolids concentration throughout a 7day period.
TL;DR: In this article, a smoothed particle hydrodynamics approach was used to model a non-Newtonian fluid with a spatially varying viscosity, which was compared with numerical solutions of the general Navier-Strokes equation using the regularized Bingham model of Papanastasiou.
Abstract: A smoothed particle hydrodynamics ap- proach is utilized to model a non-Newtonian fluid with a spatially varying viscosity. In the limit of constant viscosity, this approach recovers an earlier model for Newtonian fluids of Espanol and Revenga (Phys Rev E 67:026705, 2003). Results are compared with numerical solutions of the general Navier-Strokes equation using the "regularized" Bingham model of Papanastasiou (J Rheol 31:385-404, 1987) that has a shear-rate- dependent viscosity. As an application of this model, the effect of having a non-Newtonian fluid matrix, with a shear-rate-dependent viscosity in a moderately dense suspension, is examined. Simulation results are then compared with experiments on mono-size silica spheres in a shear-thinning fluid and for sand in a calcium carbonate paste. Excellent agreement is found between simulation and experiment. These results indicate that measurements of the shear viscosity of simple shear- rate-dependent non-Newtonian fluids may be used in simulation to predict the viscosity of concentrated sus- pensions having the same matrix fluid.
05 Mar 2010
TL;DR: In this article, the surface tension and viscosity of Al2O3•H2O nanofluids were investigated using the maximum bubble pressure method and a capillary viscometer, respectively.
Abstract: Nanofluid is a kind of new engineering material consisting of solid nanoparticles with sizes typically of 1–100 nm suspended in base fluids. Due to the importance of thermophysical property on the heat transfer behavior of fluids, the surface tension and viscosity of Al2O3‐H2O nanofluids were investigated. The tests of nanoparticle concentrations ranged from 0 g/l to 1 g/l. The measurements of surface tension and viscosity were equipments based on the maximum bubble pressure method and a capillary viscometer, respectively. The results showed that the surface tension and the viscosity of nanofluids are both highly dependent on the temperature, which is the same to those of water. Because the nanoparticle concentration studied in this work is very low, so there is no obvious change for the viscosity and a maximum enhancement only about 5% for surface tension is obtained at a concentration of 1 g/l.
TL;DR: In this paper, the degradation of a series of semi-dilute aqueous solutions of PEO of varying molecular weights and concentrations is studied in a single set-up, a micro-fabricated constriction and an on-chip viscosimeter.
Abstract: A complex fluid submitted to strong flows can endure irreversible changes in its structure. This is the case for long chain polymer additives that are commonly used as viscosity enhancers in industry, notably for oil recovery. These polymers break in solution when submitted to high deformation rates, eventually causing a serious viscosity loss. This problem of practical importance is though difficult to handle from a fundamental point of view given its complexity. We introduce here a new tool, based on microfluidic technology, for the screening of the degradation of solutions in the model situation of the flow through a constriction. We integrate two functions in a single set-up, a micro-fabricated constriction and an on-chip viscosimeter. This tool enables us to probe rapidly the viscosity loss imparted by flowing through the constriction at a given flow rate. Thanks to microfluidics, the sample preparation and measurement time are significantly lower than those implied by classical measurement protocols (reduction by up to two orders of magnitude). In addition, confinement provides control of the flow in terms of inertia. To illustrate the potential of this approach in a screening perspective, we use this tool to study the degradation of a series of semi-dilute aqueous solutions of PEO of varying molecular weights and concentrations. For each solution we identify a threshold flow rate for polymer degradation. The corresponding critical deformation rate decreases with molecular weight and concentration, as expected (the mass dependence is in line with previous reports and theories for dilute solutions). In addition we characterize the viscosity loss for larger deformation rates and find that, despite the polydispersity of our solutions, the observations for the various solutions can be roughly recast on a master curve by renormalization of the imposed deformation rates according to a law M w − 1.7 ± 03 c − 0.7 ± 03 .
TL;DR: An all-quartz oscillating-disk viscometer of very high precision was used to measure the temperature dependence of the viscosity of argon in the limit of zero density.
Abstract: An all-quartz oscillating-disk viscometer of very high precision was used to measure the temperature dependence of the viscosity of argon in the limit of zero density. The measurements were based on a single calibration value at 298.15 K, which was calculated theoretically using an accurate ab initio pair potential for argon and the kinetic theory of dilute gases. The uncertainty of the experimental data is conservatively estimated to be 0.15 % temperature increasing to 0.2 % 680 K. The new data, as well as viscosities determined in 2007 at the National Institute of Standards and Technology in the range from 200 K to 400 K, agree excellently within ±0.1 % theoretically calculated viscosity of argon at zero density. On the contrary, the widely accepted viscosity data recommended by Kestin et al. (J Chem Phys 56:4119, 1972) deviate by as much as 0.9 %
TL;DR: In this paper, the authors measured the partial molar volumes and viscosity B-coefficient for sulphanilamide, sulphanilic acid, and sulphosalicylic acid dihydrate in water and in aqueous solutions of (0.05, 0.3, and 0.5) mol·kg−1 sodium chloride at temperatures from (288.15 to 318.15) K.
Abstract: The partial molar volumes V2° and viscosity B-coefficient have been measured from density and flow time measurements for sulphanilamide, sulphanilic acid, and sulphosalicylic acid dihydrate in water and in aqueous solutions of (0.05, 0.1, 0.3, and 0.5) mol·kg−1 sodium chloride at temperatures from (288.15 to 318.15) K, by the use of a vibrating tube digital densimeter and Micro-Ubbelohde type capillary viscometer, respectively. The transfer volumes at infinite dilution calculated from partial molar volumes have both positive and negative values. The overall positive values at higher concentrations of sodium chloride are in the following order: sulphosalicylic acid dihydrate > sulphanilic acid > sulphanilamide, which is also the order of hydrophilicity of these drugs. The interaction coefficients, partial molar expansibilities VE°, and second-order derivative have also been calculated. The transfer B-coefficient values, ΔtrB, are calculated from viscosity B-coefficient data. Transition state theory has bee...
TL;DR: In this article, a stable liquid/liquid annular co-laminar flow in a co-axial microfluidic device has been realized, which can be described by Navier-Stokes equations.
Abstract: This article presents a simple microfluidic method to measure the Newtonian fluid viscosity. This method is carried out in a co-axial microfluidic device. A stable liquid/liquid annular co-laminar flow in the co-axial microfluidic device has been realized, which can be described by Navier–Stokes equations. The viscosity of either fluid can be measured based on the equations when the viscosities of another fluid is known. Proper conditions to form stable annular co-laminar flow for the viscosity measurement were investigated. Several fluids were tested with viscosity ranging from 0.6 to 40 mPa s. The measured results fit very well with those measured by a commercial spinning digital viscometer. The novel method is highly controllable and reliable, and has the advantage of less time and material consumption, as well as easy fabrication of the device.
TL;DR: In this paper, a rotor-containing fluorescent dye was prepared, which can reveal a typical viscosity-sensitive behavior due to the environment-induced nonradiative decay.
TL;DR: In this paper, a new and reliable correlation for methane gas viscosity is presented, and a comparison is presented for that data common to the experimental range reported in this paper, with predicted values for temperatures up to 400 K and pressures up to 140000 kPa with Average Absolute Percent Relative Error (E ABS ) of 0.794.
TL;DR: In this article, the falling ball viscometer is used to measure viscosity under high pressure in a high-pressure autoclave fitted with visualisation windows, where balls fall through a tube open at both ends with a diameter slightly greater than that of the balls, allowing a simplified modelling and numerical simulation.
Abstract: This study presents the development of an improved technique for viscosity measurements under high pressure. The apparatus is based on the principle of the falling ball viscometer, implemented in a high-pressure autoclave fitted with visualisation windows. The originality here is that the balls fall through a tube open at both ends with a diameter slightly greater than that of the balls, allowing a simplified modelling and numerical simulation. A numerical approach has been used for viscosity determination. Calculations have been made with COMSOL Multiphysics® with the laminar Navier–Stokes model for Newtonian mixtures. It includes the specific hydrodynamic effects without the need for a calibration fluid. However, validation experiments were carried out at atmospheric pressure with dimethylsulfoxide (DMSO) at 298, 308 and 318 K and with cocoa butter at 313 and 353 K, with values of viscosity in the range from 1.4 to 45.4 mPa s. Comparative measurements with literature data have been conducted with cocoa butter saturated with carbon dioxide at 313 and 353 K and for pressures ranging from 0.1 to 25 MPa. At 313 K, viscosity varies from 45.4 mPa s to 3.1 mPa s while at 353 K it varies from 12.4 to 1.9 mPa s. For both isotherms tested, within the range 0–15 MPa, the higher the CO2 dissolution in the cocoa butter, the lower the viscosity. However, this decrease in viscosity is more pronounced at the lowest temperature. Above 15 MPa the CO2 dissolution effect on viscosity becomes insignificant, i.e. within the experimental error, due to a counter effect linked with the high hydrostatic pressure. Furthermore, the limits of use of this method have been determined. This technique is revealed as reliable and can therefore be used with other binary systems.
01 Jan 2010
TL;DR: In this paper, the dynamic viscosities of the ionic liquids were determined using an AMVn automated microviscometer Anton Paar, based on the rolling ball principle.
Abstract: Experimental part Choline chloride (ChCl) (Aldrich, >98%) was recrystallised from absolute ethanol, filtered and dried under vacuum for ten hours. Urea, malonic acid (Merck, >99%) and ethylene glycol (Merck, >99.5%) were used as received. The eutectic mixtures were formed by stirring the two components at 100°C until a homogeneous colourless liquid was formed. Samples were prepared and stored into a dry-nitrogen glove-box prior to measurements. Precautions were made to avoid the contact of the samples with atmospheric humidity. Densities, ρ, were measured at atmospheric pressure with a DMA 4500 Anton Paar oscillating U-tube densitometer with a precision of ± 0.00005 g cm -3 which includes an automatic correction for the viscosity of the sample. The sample thermostatting was controlled to ±0.01 K. The dynamic viscosities, η, of the ionic liquids were determined using an AMVn automated microviscometer Anton Paar. The automated micro viscometer is based on the rolling ball principle. The sample to be measured was introduced into a glass capillary in which a steel ball rolls. The viscosity of the test fluid can be determined by measuring the rolling time of the steel ball. A built-in Pt100 thermometer measures and controls the exact temperature. The capillary was calibrated and credited by the manufacturer company. The experimental uncertainty was lower than ±2 mPa s for the viscosity range of (300 to 700) mPa s and ±0.3 mPa s for the viscosities less than 300 mPa s. Results and discussions
TL;DR: In this article, an aluminum sphere is rotated in a sample cell under a rotating external magnetic field, and the rotational speed of the sphere gives the sample viscosity, since the viscous torque applied to the sphere overcomes the frictional force at a sufficiently small radius.
Abstract: We have developed a simple system for viscosity measurement in the range of 10-3 to 101 Pas. An aluminum sphere revolves in a sample cell under a rotating external magnetic field, and the rotational speed of the sphere gives the sample viscosity. Low viscosities can be measured by using a micro-probe sphere, since the viscous torque applied to the sphere overcomes the frictional force at a sufficiently small sphere radius. The system is free from contamination and can be easily applied to medical and biological studies.
TL;DR: In this article, the authors used a rotational viscometer to characterize RBC sludge at different solid contents (TSS = 32.2 g/L-50.2g/L) and temperatures (5-40 °C).
Abstract: The rheological characterization of sewage sludge at different steps of wastewater treatment is important since it allows predicting and estimating sludge behavior when submitted to almost all treatment and disposal operations. Rotating biological contactor (RBC) is being widely used for wastewater treatment, which is a biological treatment process following primary treatment. The rheological characterization of RBC sludge at different solid contents (TSS = 32.2 g/L–50.2 g/L) and temperatures (5–40 °C) was carried out using a rotational viscometer. The RBC sludge showed a shear-thinning behavior, where the apparent viscosity decreased rapidly with the shear rate reaching the limiting viscosity (n) at the infinite shear rate. An exponential relationship described the evolution of the limiting viscosity with the sludge TSS content. In addition, a dramatic increase in the limiting viscosity beyond a TSS concentration of 42.4 g/L has been observed. On the other hand, Bingham model described well the non-Newtonian behavior of sludge suspensions. It was clear that the yield stress is more sensitive than the Bingham viscosity for the variation in temperature and solid content. However, the rheological results revealed that both the limiting and Bingham viscosities have the same behavior with the TSS content and with the temperature.
TL;DR: In this article, the effect of different compounds on mixture thermophysical properties and the validity of available predictive models was analyzed using an electromagnetic piston viscometer with a comparison to available reference data for pure methane.
Abstract: Viscosity is among the most relevant properties required for the reliable and economic design of natural gas processing and transport units. However, the available viscosity data covering wide pressure and temperature ranges are scarce. This worldwide research project has a goal of producing accurate thermophysical properties for synthetic natural gas mixtures in a systematic manner using state-of-the-art techniques. The main purpose of the work is to analyze the effect of different compounds on mixture thermophysical properties and the validity of available predictive models. In this work, the viscosity measurements for the first two studied samples, QNG-S1 and QNG-S2, cover the temperature range (250 to 450) K and pressure range (10 to 65) MPa. Experimental measurements utilized an electromagnetic piston viscometer with a comparison to available reference data for pure methane. Using the reported results to probe the predictive ability of several theoretical models leads to unsatisfactory results. This ...
01 Jan 2010
TL;DR: In this paper, the rheological properties of self-consolidating concrete (SCC) incorporating various percentages of metakaolin (MK) and silica fume (SF) as a partial replacement of cement were evaluated at different slump flow values using a concrete viscometer.
Abstract: This study deals with the rheological properties of self-consolidating concrete (SCC) incorporating various percentages of metakaolin (MK) and silica fume (SF) as a partial replacement of cement Plastic viscosity and yield stress were evaluated at different slump flow values using a concrete viscometer The effect of high range water reducing admixture (HRWRA) dosage and the total time for flow, the time to reach 500 mm diameter (T50), and the final diameter of the slump flow test were also investigated and studied in this research program The results showed that the plastic viscosity and the yield stress increase with the increase of the percentage of MK The results also demonstrated a correlation between the final slump flow diameter and the yield stress similar to that presented in the literature
TL;DR: Results for measurement of the shear-rate-dependent viscosity of carbon-black pigmented water-based inkjet inks at shear rates up to 2 x 10(5) s(-1) are discussed and the Cross model was found to closely fit the experimental data.
Abstract: A capillary viscometer developed to measure the apparent shear viscosity of inkjet inks at high apparent shear rates encountered during inkjet printing is described. By using the Weissenberg–Rabinowitsch equation, true shear viscosity versus true shear rate is obtained. The device is comprised of a constant-flow generator, a static pressure monitoring device, a high precision submillimeter capillary die, and a high stiffness flow path. The system, which is calibrated using standard Newtonian low-viscosity silicone oil, can be easily operated and maintained. Results for measurement of the shear-rate-dependent viscosity of carbon-black pigmented water-based inkjet inks at shear rates up to 2×105 s−1 are discussed. The Cross model was found to closely fit the experimental data. Inkjet ink samples with similar low-shear-rate viscosities exhibited significantly different shear viscosities at high shear rates depending on particle loading.
TL;DR: In this article, the intrinsic viscosity and gel strength of pectin gels at different temperatures (4 °C, 25 °C and 40 °C) were investigated using a rolling ball viscometer and a texture analyser respectively.
TL;DR: In this article, the effects of rare earth oxides on the behavior of soda-lime-silicate glass were investigated by the rotating crucible viscometer, the melting temperature and activation energy for viscous flow of the studied melt were derived on the basis of the Arrhenius Equation, the coefficient of thermal expansion, glass transition temperature and dilatometric softening temperature were also determined with dilatometry, in order to reveal the effects the rare earth elements on the behaviour of soda.
TL;DR: In this article, the properties of CO2-cocoa butter (CB) saturated mixture were measured using vibrating tube technology at pressures ranging from 0.1 to 25 MPa.
Abstract: The use of supercritical carbon dioxide technology for lipid processing has recently developed at the expense of traditional processes. For designing new processes the knowledge of thermophysical properties is a prerequisite. This work is focused on the characterization of physical and thermodynamic properties of CO2-cocoa butter (CB) saturated mixture. Measurements of density, volumetric expansion, viscosity and CO2 solubility were carried out on CB-rich phase at 313 and 353 K and pressures up to 40 MPa. The experimental techniques have previously been compared and validated. Density measurements of CB and CB saturated with CO2, were performed using the vibrating tube technology at pressures ranging from 0.1 to 25 MPa. Experimental values correlated well with the modified Tait equation. CO2 solubility measurements were coupled to those of density in the same pressures ranges. At 25 MPa, the solubility of CO2 is 31.4 % and 28.7 % at 313 and 353 K. Phase behaviour was investigated using a view cell in order to follow the expansion of the CB-rich phase with the rise in pressure. Volumetric expansion up to 47 % was measured and correlated to the CO2 solubility. Phase inversion was observed at 313 K and 40 MPa. Lastly, we developed an innovative falling ball viscometer for high pressure measurements. Viscosity measurements were carried out up to 25 MPa showing a viscosity reduction up to 90 % upon CO2 dissolution. These results were correlated with two empirical models. A new model here presented, was favourably compared with the Grunberg and Nissan model. All the experimental results are consistent with the available literature data for the CB-CO2 mixture and other fat systems. This work is a new contribution to the characterization of physical and thermodynamic behaviour of fats in contact with CO2 which is necessary to design supercritical fluid processes for fats processing.
TL;DR: In this article, the authors used the falling sphere technique to determine the viscosity of high-pressure melts at the European Synchrotron Radiation Facility (ESRF) in Paris-Edinburgh cell with in situ X-ray radiography.
Abstract: Knowledge of the viscosity of high-pressure melts is important in various domains of research, such as geosciences or materials science. Experimentally, the viscosity of liquids can be determined using the falling sphere technique. This method has been developed at high pressures and high temperatures at Beamline ID27 of the European Synchrotron Radiation Facility (ESRF), combining a Paris–Edinburgh cell with in situ X-ray radiography. The press is interfaced to Soller slits and imaging systems to measure high-quality diffraction patterns and high-resolution X-ray images of the sample. The viscosity of the liquid is derived from the velocity of a dense sphere falling through the pressurized melt and the Stokes law. An optimized two-circle diffractometer allows for moving the press upside down in order to perform a series of measurements on a single sample. The simultaneous collection of X-ray diffraction data on liquids offers the unique opportunity of investigating the relations between viscosity and the...