Showing papers on "Viscometer published in 1983"

Coaxial-disk flow of an Oldroyd-B fluid: exact solution and stability

Abstract: This paper reports an exact solution for the coaxial disk flow of an Oldroyd-B fluid. The flow is approximately generated by the parallel-plate viscometer. Asymptotic and numerical solutions are reported showing that there is a critical Weissenberg number based on the angular velocity and the Maxwellian relaxation time, above which the flow is unstable. A linearized stability analysis for the basic inertialess flow confirms this numerical instability and yields the critical Weissenberg number.

Viscosity-temperature relationships at 1 atm in the system diopside-anorthite

Abstract: Laboratory measurements of the viscosities of nine compositions on the diopside-anorthite join were made with a concentric-cylinder viscometer at temperatures between approximately 1200 and 1600 degrees C in air. Viscosities were measured both above the liquidus and in the supercooled liquid region. Viscosities were independent of shear rate, indicating Newtonian viscous behavior for the melts. Viscosities decreased with increasing temperature and, at constant temperature, they decreased with increasing amounts of diopside component in the mixtures. The temperature dependence of the viscosity above the liquidus was fitted to an Arrhenius relationship from which activation energies for viscous flow, ranging from 61 kcal/mole for a melt of anorthite composition to 38 kcal/mole for a melt of diopside composition, were derived. Viscosities over the entire range of melt and supercooled liquid temperatures were fitted by the method of least squares to the Fulcher equation. The fit was better than 0.02 in log viscosity.--Modified journal abstract.

Vibrating wire measurements in liquid 3 He. I. The normal state

Abstract: A vibrating wire viscometer has been constructed using superconducting wire of diameter 58 µm in the form of a semicircular loop of radius 1.4 cm fixed at both ends and oscillating in a direction perpendicular to the plane of the loop. The use of the viscometer to measure the viscosity of normal phase3He is described and the corrections that have been applied to the data to allow for the finiteQ of the resonance, a quasiparticle mean free path comparable to the wire diameter, and a viscous penetration depth comparable to the size of the channel containing the wire are discussed. The measured viscosities show small departures from the ηT 2=const law of Fermi liquid theory similar to those observed in some but not all previous measurements. The values of the viscosity at the superfluid transition temperature agree with those obtained in other measurements.

Das Kapillarschlauch-Plasmaviskosimeter Ein neues Meßgerät zur Quantifizierung der Blutplasmaviskosität The Capillary Tube-Plasma Viscometer A New Instrument for the Measurement of the Plasma Viscosity

Abstract: Utilisation d'un tube en polyurethanne comme capillaire de mesure, tube qui est change a chaque mesure evitant ainsi les erreurs

Blood and plasma viscosity of winter flounder: influence of temperature, red cell concentration, and shear rate

Abstract: The effects of temperature, red cell concentration, and shear rate on the viscosity of blood from the winter flounder (Pseudopleuronectes americanus) were evaluated using a cone-plate viscometer. The viscosity of blood and plasma was shear rate dependent at all temperatures studied (−1 to 20 °C) with the highest values occurring at the lowest temperature and shear rate. At normal hematocrits (20%), plasma appeared to account for at least 50% of the total blood viscosity. The effects of hematocrit on viscosity were dependent on temperature. At higher temperatures (10–20 °C), increases in hematocrit resulted in a near-exponential increase in viscosity. At lower temperatures (5 °C) and shear rates (4.5 s−1) no significant increase in viscosity occurred between hematocrits of 11 and 43%. The influence of temperature and shear rate on blood viscosity suggest that winter flounder may have to contend with a fivefold increase in blood viscosity when acclimating from summer to winter water temperatures.

Errata: Vibrating wire measurements in liquid 3 He. II. The superfluid B phase

Abstract: Measurements with a vibrating wire viscometer in superfluid3He-B at temperatures down to 0.6 mK are described. The need to consider compressibility of the superfluid component in any analysis of vibrating wire measurements is clearly demonstrated and a theoretical calculation of the force acting on a vibrating wire in a finite compressible superfluid is given. The experimental data are consistent with this calculation if theoretical values of the second viscosity ξ3 are used in the analysis. The failure of the hydrodynamic theory when the quasiparticle mean free path1 is comparable to the wire radius a was observed, and an expression has been deduced for the force acting on the wire when1 is finite. Experimental and theoretical evidence is presented to show that this expression is valid for arbitrary1/a. Values of the viscosity obtained using this expression agree with those obtained in other experimental work and confirm the large discrepancy with theoretical calculations at low reduced temperatures.

Nonlinear interfacial stress-deformation behavior measured with several interfacial viscometers

Abstract: Two techniques for measuring nonlinear interfacial stress-deformation behavior using rotational interfacial viscometers are proposed. Either a single bob can be used or two bobs of slightly different radii can be employed. A series of experiments with the interface between air and an aqueous solution of 0.1 wt% dodecyl sodium sulfate have been carried out using the disk, knife-edge, and thin biconical bob interfacial viscometers. Four sets of data have been analyzed using the single-bob technique. Data for two disks also have been analyzed by the double-bob technique. Agreement among the results supports the validity of the proposed methods. The same system has been studied in a deep-channel interfacial viscometer. For the first time, consistent measurements of interfacial stress-deformation behavior have been obtained from two different interfacial viscometers.

An automated viscometer based on high-precision flow injection analysis. Part II. Measurement of viscosity and diffusion coefficients

Abstract: It is shown that viscosities in the range of 02–190 cP can be determined on 60-µl samples, in an analysis time of about 1 min with reasonable accuracy and a precision of 02–03% The method is based on timing a sample injected into a flowing carrier stream over a fixed distance The factors affecting the dispersion of the sample within the carrier stream have been critically investigated It is shown that chemical interactions, especially hydrogen bonding, between the sample slug and the carrier stream can crucially affect the dispersion pattern, so that correct choice of carrier is essential for the success of the method It can also be used for the determination of molecular diffusion coefficients and it is possible that it could be adapted to cover a wider range of viscositiesThe implications of the study to flow injection analysis are discussed

A High Precision Capillary Viscometer and Further Relative Results for the Viscosity of Water

Abstract: A suspended-level capillary viscometer with some unusual features has been developed for use with pure liquids and liquid mixtures whose viscosities are affected by evaporation or exposure to the atmosphere. The timing system requires that the test liquid be at least weakly conducting. Excellent reproducibility of the flow time of water has been obtained with this instrument. Results for the viscosity of water in the temperature range 1 °C to 70 °C compare favourably with published values in terms of self-consistency. Estimates of the kinetic energy correction for capillaries with flared entries and exits have been made, and accord best with a t-2 dependence.

Measuring the Effect of Oil Viscosity on Oil Film Thickness in Engine Journal Bearings

Abstract: The minimum oil-film thickness in the front main bearing of a 3.8 L, V-6 engine was measured at 3,000 r/min, and 140 N.m using an electrical resistance technique. For a series of seven Newtonian, single-grade oils, film thickness correlated with oil viscosity measured either in a kinematic or in a high-shear-rate viscometer. For a series of fifteen polymer-containing, non-Newtonian, multigrade oils, however, no single measure of viscosity adequately correlated with film thickness for all of the oils. By eliminating four multigrade oils from the combined single and multigrade data sets, it was possible to correlate film thickness to the viscosity (of the remaining multigrade and Newtonian oils) measured at 150 deg C and 500,000/s, conditions which are believed to be representative of temperatures and shear rates in bearing oil films. Possible explanations for the lack of correlation with the entire set of twenty-two oils are discussed.

Effects of isotropic pressure on the high temperature high shear viscosity of motor oils

Abstract: The viscosity of 10W/40 motor oils formulated with different viscosity index (VI) improvers has been measured at pressures up to 200 MPa (2000 bar) over a wide temperature and shear rate range. The response of viscosity to pressure was found to depend on the chemical nature of the VI improver at both low and high shear rates. As a consequence, the ranking of the 150 degree C viscosities of polymer-thickened oils can be different at high pressures to that observed in conventional atmospheric pressure viscometers. These effects of VI improver type on high pressure viscosity appear to be relevant to wear in journal bearings of fired engines; thus in experiments carried out in the ALI Bearing Distress Test, bearing weight loss of multigrade oils containing different VI improvers correlated better with high pressure, high shear viscosities than with high shear viscosities measured at atmospheric pressure.

An automated viscometer based on high-precision flow injection analysis. Part I. Apparatus for high-precision flow injection analysis

Abstract: The development of an automated viscometer is described. It is a modified Ostwald viscometer in which the sample to be determined is injected into a suitable carrier stream flowing along a narrow-bore tube. The time taken for the sample to traverse a fixed distance is directly proportional to the viscosity. The sample size is typically 50 µl and the time of determination 30 s, with a precision of 0.2–0.3%, for samples of viscosity 0.2–190 cP (a greater range is attainable in principle by minor alteration of the tube parameters). It may be operated in the reverse mode by using a carrier stream of unknown viscosity and injecting a sample of known viscosity. In this way it way it may be used for continuous monitoring. A number of detectors have been devised and evaluated and several microcomputer systems have been employed in the development and these are described and discussed.In order to obtain high precision, numerous theoretical and practical factors that affect the dispersion of the sample have been investigated. It is shown that it is critically dependent on chemical factors, such as hydrogen bonding between the sample and carrier, which is discussed in Part II. The instrumental factors that most critically affect the precision are shown to be as follows: the use of two detectors to measure the timing of flow-rate and the sample profile, thereby circumventing the role of the inlet valve as a timing device; the rate of data collection, about 100 points per peak being the optimum, together with a good data processing algorithm and control of the temperature to within ±0.1 °C.

Polyelectrolyte adsorption from saline solutions

Abstract: Publisher Summary This chapter presents an overview of the study of the adsorption of polyelectrolytes from saline solutions. In the method described in the chapter, the intrinsic viscosity of polystyrene sulfonate samples in saline solutions was measured in a Viscometer, equipped with a capillary that had a flow time of ca. 230 s for water. For uncharged polymers, it is possible to define a polymer–solvent interaction parameter from the molecular weight dependency of using a Flory–Fox–Schaefgen or a Burchard–Stockmayer–Fixman plot. For lower potentials or at higher cs, the screening by the salt suppresses the minimum and increases the adsorbed amount, while the profile becomes gradually similar to that of uncharged polymer. Purely electrostatic effects greatly influence the adsorption at very high salt concentration. This is related to the interpenetration of small ions between the individual polyion charges, which is not analogous to the two-dimensional screening effect of salt between two impenetrable colloid particle surfaces. One of the most salient features of this polyelectrolyte adsorption is that the effect of electrolytes can be well represented by the Poisson–Boltzmann picture up to concentrations of order 1-3 M, which is far beyond the usually accepted limit of applicability.

Viscous flow behavior of four iron‐containing silicates with alumina, effects of composition and oxidation condition

Abstract: The viscosity of four iron-containing silicates with alumina has been measured under oxidizing and reducing conditions over the temperature range 450° to 700°C. Initially, the compositions contain approximately 2, 5, 10, and 20 mol.% of trivalent metal oxide. The viscosities of compositions with approximately equimolar Fe3+ and Al3+ are compared to those determined for compositions with trivalent cation all Fe or all Al. Then the batch composition calculated to replace one half of the Fe3+ by Al3+ under oxidizing conditions is corrected for the divalent iron present under mildly reducing conditions in forming gas (95% N2-5% H2) and strongly reducing conditions with carbon. In general, the viscosity measured in air was higher than the viscosity measured in forming gas with or without carbon for a given temperature and composition. The glasses prepared under oxidizing conditions had Fe2+/Fe total ratios less than 0.25 and the glasses prepared under reducing conditions had Fe2+/Fe total ratios between 0.27 and 0.91. The viscosities for these glasses can be represented by a Vogel-Fulcher relation for each of the three oxidation conditions.

Cold-slurry viscosity of processed rice flour.

Abstract: Viscosities of dispersions of raw and various processed rice flours in water were examined with a coaxial cylinder viscometer. Viscosity increased with increasing degree of processing and with a reduced level of apparent starch reassociation in processed rice. Measurement of apparent viscosity of cold slurries could thus be a simple practical test of processed, including parboiled, rice and of the degree of processing. The system showed time-dependent thinning and a typical loop in the shear rate-viscosity curve, showing that it was thixotropic in nature. Viscosities were proportional to hydration power and slurry-sedimentation behaviour of the samples.

Studies of blood viscosity with a newly constructed rotational viscometer which operates via a desk top computer.

Abstract: Increasing interest is being shown in blood viscosity and the whole field of haemorheology. This study presents a newly constructed rotational Couette type viscometer which operates via a commercially available desk top computer and a digital plotter. The influence of haematocrit on blood viscosity is shown and the study also presents blood viscosity values of six to eight healthy men at 24°C and 37°C. At 37°C values are shown both at natural haematocrit and at haematocrit 45%.

Dynamic viscosities of milk and cream from 70 to 135 °C

Abstract: The dynamic viscosities of non-homogenized and homogenized (2-stage) whole and half skim-milk and cream, of unhomogenized skim-milk and of water-diluted milks were measured at temperatures between 70 and 135 °C; this range includes those temperatures used in ultra-high-temperature (UHT) treatments. A tube viscometer was used at the outlet of a continuous flow indirect heater. Above 85 °C the mean residence time of a milk or cream at the test temperature was 3–6 s.An equation relating viscosity μ and temperature θ of the form In μ = aθ2+bθ+c was derived for each product.It proved possible to relate μ, θ and fat content (0·03–15·5%) in a single equation which was appropriate for all the homogenized milks and creams as well as the non-homogenized skim-, half skim- and whole milk; the equation is considered valid for these products under conditions of indirect UHT sterilization. Viscosity values calculated with the equation, even those relating to temperatures as low as 50 °C, were comparable with those reported in the literature.

Theoretical and experimental studies on the formation of an air core in a swirl spray pressure nozzle using a power law non-Newtonian liquid

Abstract: An extension of the recent work [15] has been made to evaluate the air core diameter both theoretically and experimentally in the case of a swirl nozzle using a time independent pure viscous power law non-Newtonian fluid. The theoretical predictions have been made through an approximated analytical solution of the hydrodynamics of flow inside the nozzle. A series of experiments has been carried out with solutions of CMC (carboxymethyl cellulose sodium salt) powder in water with different concentrations as the working fluids. The rheological properties of the working fluids were measured by a capillary tube viscometer. Finally it has been recognised from both the theory and experiment that, regarding the injection condition and the fluid properties, the generalised Reynolds number \(\operatorname{Re} _{G_i } \) at the inlet to the nozzle and the flow behaviour index n of the fluid become the pertinent independent input parameters in non-dimensional forms. The air core diameter increased with \(\operatorname{Re} _{G_i } \) and decreases with n. The effect of nozzle geometry on the air core diameter is similar to that in the case of Newtonian fluids [15].

Variable volume dual action rheometer

Abstract: The invention comprises a device which performs the functions of both a Mooney Viscometer and an Oscillating Disk Rheometer to measure the visco-elastic properties of rubber and rubber-like materials Rotational and oscillating motion are transmitted to a shaft by means of a sprocket and a hub connected to an eccentric Rubber samples having a wide range of stiffnesses can be accommodated by a provision for changing the thickness of the sample

Flow birefringence and viscosity of chitosan solutions in acetic acid of various ionic strengths

Abstract: Chitosan solutions of different ionic strength I were studied, using viscometry and double flow birefringence. The MWs of the samples used were in the range 1 × 104–5 × 105. A linear dependence of intrinsic viscosity on chitosan concentration in a 100 fold range of I was observed in iso-ionic solutions. The characteristic viscosity is a linear function of I−0.5. Folding of the molecular chain during polyelectrolyte swelling causes 2–3 fold increase in the optical anisotropy of the segment, which is explained by an increase in the length of the Kuhn segment. In the solutions studied, the chitosan macromolecules have a swollen coil conformation, the dimensions and rigidity of which are determined by the magnitude of I.

Couette Viscometry of Casson Fluids

Abstract: The solution of the equations of motion for a Casson model non‐Newtonian fluid in a rotational Couette viscometer is presented. Proper equations for determination of rheological parameters from data obtained from commercial viscometers are derived and presented. Sample curves illustrating the influence of viscometer geometry on the rheogram are presented.

Flow Properties of Alicyclic Compounds as Traction Fluids

Abstract: Several alicyclic compounds, model compounds of traction fluids, were synthesized and the high-pressure viscosity was measured with a rolling viscometer The relation between the molecular structure of the synthetic alicyclic compounds and their activation quantities for viscous flow is discussed A useful structure-property guideline for the design of better traction fluids is presented The relation between these flow activation quantities is also discussed It was found that his relation could be used to estimate the pressure dependence of the viscosity from the temperature dependence of the viscosity

The Viscosity of Carbon‐Monoxide Mixtures with Four Gases in the Temperature Range 25–200°C. Supplement

Abstract: The paper reports new, absolute measurements of the viscosity of carbon monoxide (CO) with krypton (Kr), carbon dioxide (CO2), methane (CH4) and carbon tetra-fluoride (CF4). The measurements have been carried out in an oscillating-disk viscometer at a pressure of 0.1 MPa in the temperature range 25–200 °C. The accuracy is estimated to lie between ± 0.1 % and ± 0.2%. The data have been correlated by means of the two-parameter extended law of corresponding states. They have been utilized to derive binary diffusion coefficients. This paper is a supplement to an earlier publication on mixtures with He, Ne, Ar, and N2. The great similarity between the viscosity of binary mixtures with N2 and CO, respectively, is confirmed to a high degree of accuracy.

Viscosities of aqueous solutions of alkanoic acids.

Abstract: Viscosities of aqueous solutions of alkanoic acids including formic acid were measured by an Ostwald type viscometer at 15, 25, and 35 °C, and the viscosity B-coefficient and the temperature dependence of B-coefficient, dB⁄dT, were calculated. From the signs and the magnitudes of Bst, increment of B-coefficient arising from the change of water structure, and dB⁄dT, it was concluded that formic acid was a hydrophilic structure breaker, while acetic acid was neither a structure maker nor a structure breaker. Both propionic acid and butyric acid were the hydrophobic structure makers. The mechanism of structure breaking effect of carboxyl group was briefly discussed.

Physical theory of some interface phenomena in hemorheology.

Abstract: The following four subjects are discussed theoretically from a physical standpoint: (1) the effect of the wall of a capillary viscometer on the apparent viscosity of blood; (2) the effect of electric charge on capillary flow; (3) the electric aspect of platelet adhesion and aggregation; and (4) multiphase polymeric materials as antithrombogenic materials. Copley and Scott Blair found a remarkable decrease in the apparent viscosities of blood, plasma, and serum in a fibrin-coated glass tube as compared with those in a glass tube without fibrin-coating. It is shown that the phenomenon cannot be explained by the existence of an electric double layer unless the zeta potential is positive. It is suggested that a reduction of the apparent viscosity of blood may be explained by a slight increase in the thickness of a plasma layer. It is shown that the existence of a slight gap between red cells and the capillary wall due to an electrostatic repulsion will remarkably lower the capillary flow resistance. An electric aspect of endothelial injury is discussed in relation to the adhesion of platelets to the injured endothelium. Platelet aggregation is discussed in accordance with the theory of Verwey and Overbeek , and a possible mechanism of thrombus formation due to a turbulent motion of blood is suggested. The significance of a multiphase polymeric material for an antithrombogenic surface is emphasized. It is suggested that sufficiently large conformational change of macromolecules will be favorable to antithrombogenicity of a polymeric material.

Rheology of coal suspensions

Abstract: Proper design of operations encountered in preparation, transport and employment of suspensions like coal slurries and coal-oil mixtures require an accurate knowledge of their rheological behaviour. Such concentrated suspensions generally exhibit non-Newtonian behaviour (shearthinning) which is more pronounced at higher coal concentrations. The nature of the dispersing medium influences the aggregation state of the disperse phase and, consequently, affects the stability and the rheology of the systems. In the present paper coal suspensions prepared with different dispersing media and covering a wide range in solid phase concentration are studied, by using a rotational coaxial cylinders viscometer. Different models have been taken into consideration for correlating experimental data. In particular, in order to describe the dependence of viscosity on shear rate and solid phase concentration, the suitability of the model suggested by Smith and Bruce is evaluated. Accordingly, the aggregation state of the disperse phase as well as its dependence on shear rate and dispersing medium can be estimated.

Solvent effects on the rheology of aqueous polyacrylamide solutions

Abstract: The influence of solvent chemistry on steady shear viscosity and first normal stress difference for aqueous polyacrylamide solutions (Separan AP-273) was investigated in the Weissenberg rheogoniometer and capillary tube viscometer. It was found that these rheological properties are particularly sensitive to the chemistry of the solvent. For example, the zero shear rate viscosity of a 1000 wppm Separan solution with distilled water as the solvent was greater than that with Chicago tap water as the solvent by a factor of 25, while the first normal force difference varied by a factor of two. The addition of an acid or a base to the Chicago tap water-Separan solution also influenced the zero shear rate viscosity and first normal force difference. It was found that there is an optimum pH of approximately 10 which yields a maximum value of the zero shear rate viscosity for the Separan-tap water solution. Limited data on the influence of solvent chemistry were obtained for 5000 wppm aqueous solutions of...