Showing papers on "Viscometer published in 1973"
TL;DR: In this article, a coaxial cylinder viscometer was used to evaluate the viscosities of liquid and semi-solid foods by tilting the containers and also by stirring the contents with a spoon.
Abstract: Flow properties of several liquid and semi-solid foods were characterized objectively with a coaxial cylinder viscometer. At the same time, a sensory evaluation panel compared the viscosities of these samples by tilting the containers and also by stirring the contents with a spoon. Correlation of the instrumental and sensory evaluation data established the shear stress-shear rate conditions prevailing during sensory evaluation of viscosity. The stimulus responsible for viscosity evaluation by tilting the container is the shear rate (0.1–40 sec-1) developed at a shear stress (60–600 dyne cm-2) related to the flow properties of the sample, whereas in stirring tests the stimulus is the shear stress (102–104 dyne cm-2) developed at a particular rate of shear (90–100 sec-1). In the latter type of test, the shear rate varies to some degree with the flow characteristics of the sample. Since different stimuli are involved in viscosity assessment by tilting the container or by stirring, it is possible for a series of samples to be given different ranking orders by the two methods of evaluation.
359 citations
TL;DR: The coefficient of shear viscosity of fluid argon has been measured at temperatures from 85 to 298 K and at pressures up to 34 MN/m2 using the torsional crystal viscometer as discussed by the authors.
87 citations
TL;DR: By comparing the experimental data with the hydrodynamic theories of wormlike‐coil of Ullman a value of 1300 Å has been assigned for the persistence length of these tropocollagens.
Abstract: Sedimentation constant and intrinsic viscosity were measured on purified tropocollagens extracted from earthworm-cuticle and lathyritic ratskin A cartesian diver viscometer was used to make viscosity measurements at small shear stress and to avoid the effects of surface forces By comparing the experimental data with the hydrodynamic theories of wormlike-coil of Ullman a value of 1300 A has been assigned for the persistence length of these tropocollagens Other factors which may affect the estimate are discussed
55 citations
TL;DR: In this article, various kinds of capillary viscometers have been used in the past, and the relation between the measured quantities and the viscosity of the fluid has been formulated.
Abstract: The purpose of this work is to analyze the various kinds of capillary viscometers that have been used in the past, and to formulate the relation between the measured quantities and the viscosity of the fluid. Three kinds of capillary viscometers are discussed: the steady-state capillary, two capillaries in tandem and the Rankine viscometer. Improved working formulae are derived for every case. Throughout the work the fluid is assumed to be incompressible. However, a short discussion of the correction for compressibility is also provided.
53 citations
TL;DR: In this paper, the authors reported new measurements of the viscosity of oxygen and air, and of the binary mixtures O2-Ar, O2Kr and N2-O2, together with check values for the pure gases which appear in them.
48 citations
TL;DR: In this article, it is suggested that the different types of flow arises from the fact that the overall viscosity depends not only on the temperature and composition of the residual vitreous phase, but to an even greater extent on the lava s crystal and bubble content.
Abstract: Measurements have been made of viscosity and temperature for the 1971 and older lavas. Viscosities were estimated by two complementary methods: the classical measurements of the flow rate, and a ballistic method, in which the apparent viscosity of the surface layers was deduced from the depth of penetration of a steel spear, perpendicularly injected into the lava flow. Laboratory measurements on lava samples have been made with rotating cylinder viscometers. The principal result of the work indicates that between the bocca and the flow front the flow behaviour, and consequently the viscosity may vary considerably from lava to lava, even though the original magma varies little in composition. It is suggested that the different types of flow arises from the fact that the overall viscosity depends not only on the temperature and composition of the residual vitreous phase, but to an even greater extent on the lava s crystal and bubble content. The devitrification, which is a determinant factor of the rheological properties, is in turn highly influenced by the temperature of eruption and the rate of cooling of the lava.
48 citations
01 Dec 1973
TL;DR: In this paper, the authors established a correlation of wall and inertial corrections to Stokes' law in the range appropriate for falling sphere viscometry, and presented this correlation in a manner convenient for application.
Abstract: The classical expression for determining viscosity from sphere fall velocity is Stokes' law Stokes' law applies in the absence of wall and inertial effects In the usual experimental apparatus there are wall effects and there may be inertial effects The objective of this paper is to establish a correlation of wall and inertial corrections to Stokes' law in the range appropriate for falling sphere viscometry, and to present this correlation in a manner convenient for application The desired correlation is presented in Table II and Figure 5 of the text The new correlation should be useful in determining the viscosity of Newtonian fluids and in determining the zero shear rate viscosity of polymer solutions
45 citations
TL;DR: The viscosity of 99.99% pure selenium has been determined over the available range of temperature where crystallization could be avoided as discussed by the authors, and the critical stress for non-Newtonian flow was found to lie in the range of hundreds of psi, which was appreciably smaller than that for oxide liquids in a similar range of viscosities.
Abstract: The viscosity of 99.99% pure selenium has been determined over the available range of temperature where crystallization could be avoided. A bending beam viscosimeter was used to obtain data in the high viscosity region, and a rotating cylinder instrument was employed for the low viscosity range. Also determined was the stress dependence of the viscosity at temperatures of 31.5 and 29.6°C. The critical stress for non-Newtonian flow was found to lie in the range of hundreds of psi, which is appreciably smaller than that for oxide liquids in a similar range of viscosity.
43 citations
TL;DR: In this paper, the kinematic viscosity of sea water solutions and concentrates up to 11% salt by weight and from 0 to 200°C have been measured in a pressurized glass capillary viscometer.
32 citations
TL;DR: In this article, the viscoelastic properties of elastohydrodynamic lubrication and hydraulics were studied at low rates of shear and high pressures up to viscosities rather higher than had been measured hitherto.
Abstract: IN our study of the viscoelastic properties of lubricating fluids over wide ranges of temperature and pressure, the need arose for measurements of viscosity at low rates of shear and high pressures up to viscosities rather higher than had been measured hitherto. This required the design and construction of a new form of viscometer. But we realized that such measurements could be of more immediate application in the fields of elastohydrodynamic lubrication and hydraulics. Here we report such an application in a short investigation of a rather unexpected result published recently1, that the viscosity of a liquid approaches and may even attain, a constant value as the pressure is raised.
28 citations
TL;DR: In this paper, the primary flow around a sphere rotating in Newtonian and viscoelastic liquids is investigated by using a new "three-dimensional particle technique" and the results justify the use of a rotating sphere viscometer as a useful tool for the measurement of parameters of flow curves of inelastic and viscous liquids.
Abstract: The use of a rotating sphere viscometer for the measurement of parameters in the flow curves of inelastic as well as viscoelastic liquids is examined. An experimental investigation of the primary flow around a sphere rotating in Newtonian and viscoelastic liquids is carried out by using a new "three-dimensional particle technique." Currently available theoretical analyses of rotation of a sphere in viscoelastic liquids are shown to be inadequate to describe the experimental primary velocity distribution data. Theoretical results for the primary distribution derived on the basis of a creeping flow of a power law liquid are found to describe the experimental data well. This distribution is then used to derive torque-angular velocity relationships, which are then confirmed experimentally for both inelastic and viscoelastic liquids. The results of this work justify the use of a rotating sphere viscometer as a useful tool for the measurement of parameters of flow curves of inelastic and viscoelastic liquids.
TL;DR: In this article, a vibrating wire viscometer is described which has been used to measure the viscosity of liquid helium at varying temperatures and pressures, which is usable at elevated pressures and requires only a small volume of fluid.
Abstract: A vibrating wire viscometer is described which has been used to measure the viscosity of liquid helium at varying temperatures and pressures. The viscosity is calculated from measurements of the decay time and frequency of a taut vibrating wire damped by the fluid, of the wire density and diameter, and from knowledge of the density of the fluid being measured. This viscometer is an outgrowth of one previously developed which operated only at the vapour pressure. The new device is usable at elevated pressures and requires only a small volume of fluid.
TL;DR: In this article, a method for calculating the Dean number for an unsteady state viscometer is proposed with which the flow data obtained in a curved-pipe can be satisfactorily correlated.
Abstract: The error in viscosity measurements caused when using coiled tubes has been experimentally assessed. Previous methods for obtaining a correction factor are shown to be unreliable. A method for calculating the Dean number for an unsteady state viscometer is proposed with which the flow data obtained in a curved‐pipe can be satisfactorily correlated. Experimental results obtained using a new coiled viscometer are used to illustrate how such a correction can be applied.
TL;DR: In this paper, an attempt has been made to determine the flow curve of fluids obeying the power law rheological model on a rolling ball viscometer, based on the hydrodynamical model developed byLewis in 1956 for the purpose of rolling ball-vizeter calibration and extended in 1964 byTurian andBird for the two-parametric power law model.
Abstract: An attempt has been made to determine the flow curve of fluids obeying the power law rheological model on a rolling ball viscometer. The theoretical analysis is based on the hydrodynamical model developed byLewis in 1956 for the purpose of rolling ball viscometer calibration and extended in 1964 byTurian andBird for the two-parametric power law model. The shear rate variation has been accomplished on varying the tube angle of inclination. Experiments performed on an adapted, commercialHoeppler viscometer with aqueous solutions of carboxymethylcellulose and polyacrylamide reproduced the flow curves obtained simultaneously on rotational and capillary instruments with reasonable accuracy.
TL;DR: A viscometer chamber (combination of cone plate and Couette-type) adaptable to the standard Wells-Brookfield-Microviscometer is described, which incorporates a guard ring against surface artefacts.
Abstract: A viscometer chamber (combination of cone plate and Couette-type) adaptable to the standard Wells-Brookfield-Microviscometer is described. The instrument allows measurements at shear rates between 0.23 and 160 sec−1; it incorporates a guard ring against surface artefacts. Measurements with normal human blood, standardized for hematocrit value, give excellent agreement with data obtained previously on the GDM-viscometers.
TL;DR: It was observed that dilution of blood with dextran 40 increases the blood viscosity, which is higher than the viscosities of blood alone ordextran alone, which suggests that the viscolysis of the suspending medium is relatively about as important as the hematocrit in determining the visCosity of the whole suspension.
TL;DR: In this paper, a systematic study of the excitation of different vibrational modes of the viscometer by varying the magnetic field orientation and the nature of the driving current was made.
Abstract: Measurements between 35 and 110 mK along the melting curve indicate that in the normal Fermi liquid region the viscosity of
3
He is given by (ηT
2
)−1
=a−bT
n
withn=1.0. The measured constants area=0.816 andb=4.43 for η in micropoise andT in Kelvin. Very little solid could be formed in this particular apparatus without immobilizing the vibrating wire viscometer. Patterns were observed in the solidification, however, which suggest that such a device could be operated at much lower temperatures in a compressional cooling cell of appropriate design. A systematic study was made of the excitation of different vibrational modes of the viscometer by varying the magnetic field orientation and the nature of the driving current. The use of tone burst and dc, as well as CW, excitation currents allows the same viscometer to be used over a wide range of viscosities.
TL;DR: The authors measured the viscosities of the binary gas mixtures argon-methane and argonammonia using an oscillating disc viscometer as functions of composition in the temperature range from −35 to 35°C.
Abstract: Viscosities of the binary gas mixtures argon‐methane and argon‐ammonia have been measured by an oscillating‐disc viscometer as functions of composition in the temperature range from −35 to 35°C. For the nonpolar‐nonpolar system argon‐methane, the agreement between the experimental and calculated values of mixture viscosity is fairly satisfactory. For the nonpolar‐polar system argon‐ammonia, the calculated values from the combination rules are lower than the experimental data. Attempts have been made to derive information on the unlike interactions from mixture viscosity data.
TL;DR: In this article, Fourier transform spectroscopy was used to obtain polarized infrared spectra of polyethylene, which revealed an extreme degree of orientation consistent with previous x-ray studies.
Abstract: Polarized infrared absorption spectra have been obtained by Fourier-transform spectroscopy for several crystalline and noncrystalline absorption bands of polyethylene crystallized by orientation and pressure in capillary viscometer. An analysis of data obtained at room temperature yielded degrees of crystallinity which are in good accord with values obtained from calorimetry and density measurements. The dichroism of the infrared absorption bands for the crystalline region revealed an extreme degree of orientation consistent with previous x-ray studies and also demonstrated that the degree of orientation is a good or better than that obtained from drawn polyethylene films with extension ratios of 20. Dichroism of bands from the amorphous phases revealed that the noncrystalline chain segments are in a comparatively relaxed state compared with results for drawn films having extension ratios of about 2 to 7. This is 1/10 to 1/3 the extension ratio of drawn polyethylene which shows maximum crystalline orientation. The results also indicated that the ratio of the GTG′ to GG segment conformations in the amorphous regions is larger than that of amorphous portions in unoriented polyethylene. The vinyl endgroups were shown to be highly oriented, while the main bulk of the amorphous polymer was fairly relaxed, i.e., of low orientation. It is concluded that the amorphous polyethylene state is strongly dependent on the nature of the crystalline–amorphous interface.
TL;DR: In this paper, the main design considerations for a high-shear concentric cylinder viscometer are reviewed and discussed, and the results obtained were compared to the molecular entanglement theory, and excellent agreement was observed.
Abstract: This manuscript reports on the development of a high-shear Couette viscometer. The main design considerations for a high-shear concentric cylinder viscometer are reviewed and discussed. In principle, the instrument is identical to those used by other investigators. However, some modifications were found necessary. Attention is drawn to the importance of the concentricity problem. The instrument was first tested and calibrated using Newtonian standard oils. Then non-Newtonian runs were performed using narrow polystyrene standards of molecular weights 97,200, 411,000, and 860,000. Solutions of the polymer in n-butylbenzene ranged in concentration from 0.08 g/cc up to 0.5 g/cc. The shear rates applied ranged from 103 sec−1 up to 105 sec−1. The results obtained were compared to the molecular entanglement theory, and excellent agreement was observed.
01 Jan 1973
TL;DR: In this paper, the authors evaluated the shear susceptibility parameter in relation to the performance of in-service pavements, six test pavements constructed of graded asphalt from different sources were evaluated in a closely controlled research project.
Abstract: In order to study the shear susceptibility parameter in relation to the performance of in-service pavements, six test pavements (6 experimental sections of ID-2 wearing course surfaces) constructed of graded asphalt from different sources were evaluated in a closely controlled research project. Periodic core samples were used to determine air voids in the pavements and the rheological properties of the aged asphalts. Details of the rating method for evaluation of the effect of asphalt aging on pavement condition are detailed in a reference. Viscosities were determined at 39.2 G, 77 F and 115 F over a range of shear rates, using the sliding plate microviscometer and viscosity at 140 F was determined using the Cannon-Manning Vacuum Viscometer. The aging indices were determined (considering the changes in viscosity at 77 F and viscosity at 140 F), as follows: aging index = viscosity after aging/viscosity before aging. The shear susceptibility (shear index) value as employed in this-study is the tangent of the angle of log shear rate (x-axis) versus log viscosity (y-axis) determined during performance of the viscosity test. The effects of temperature and asphalt composition on shear susceptibility are discussed. Very good correlation was observed between aging indices and shear susceptibility values of the aged asphalts. Aging index-shear susceptibility of relationship appears to determine pavement performance. Control of grain in shear susceptibility and aging index seems to be a necessary specification requirement for paving asphalts. The studies indicate that the ratio of asphaltenes to Nitrogen Bases affects the shear susceptibility of asphalts.
TL;DR: In this paper, a viscometer is described in which the capillary wall temperature is controlled by an adjustable low voltage current directly flowing through the thin tube wall, where the current can be adjusted by a voltage controller.
Abstract: A viscometer is described in which the capillary wall temperature is controlled by an adjustable low voltage current directly flowing through the thin tube wall
TL;DR: In this paper, a viscometer is described that allows the viscosity changes of poly(2-vinylpyridine 1-oxide copolymers to be followed with greater accuracy.
TL;DR: In this article, the slip correction in capillary viscometers can cause significant errors, and some of the factors which affect slip are described and suggestions are made so that inaccuracies may be avoided in future accurate viscosity determinations.
Abstract: The slip correction in capillary viscometers can cause significant errors. Some of the factors which affect slip are described and suggestions are made so that inaccuracies may be avoided in future accurate viscosity determinations.
TL;DR: In this paper, a high precision, easy to build, digital recording system has been adapted on a commerical Zimm•Crothers rotating viscometer, which allows intrinsic viscosity measurements on very diluted nucleic acid solutions.
Abstract: A high precision, easy to build, digital recording system has been adapted on a commerical Zimm‐Crothers rotating viscometer. It allows intrinsic viscosity measurements on very diluted nucleic acid solutions.
TL;DR: The absolute viscosity of gaseous air was determined experimentally for the general pressure and temperature range 100-15 000 kPa and 90-400 K respectively, using a series capillary transpiration-type viscometer which has been developed by the authors as discussed by the authors.
Abstract: The absolute viscosity of gaseous air was determined experimentally for the general pressure and temperature range 100–15 000 kPa and 90–400 K respectively, using a series capillary transpiration-type viscometer which has been developed by the authors. The accuracy of the experimental data is believed to be better than ± 1 per cent.Two general correlating equations, one for atmospheric pressure and the other for medium high pressure (i.e., densities up to 400 kg/m3), have been obtained.
TL;DR: In this article, a new type of viscometer consisting of a steel tuning fork measures viscosity over a large range in a simple and convenient way, which requires only small quantity of specimen and offers hope to determine the anisotropic viscosities of ordered fluids such as liquid crystal.
Abstract: A new type of viscometer consisting of a steel tuning fork measures viscosity over a large range in a simple and convenient way. It requires only small quantity of specimen and offers hope to determine the anisotropic viscosities of ordered fluids such as liquid crystal.
TL;DR: In this article, a method was developed for measuring the time of flow in an Ubellohde viscometer to an accuracy of 3 ppm using a thermostat with a long time thermal stability of ±2×10−4°C.
Abstract: A method was developed for measuring the time of flow in an Ubellohde viscometer to an accuracy of 3 ppm. For this purpose the following points were shown to be crucial: (a) use of a thermostat with a long time thermal stability of ±2×10−4°C; (b) closing the viscometer off to the outside during all stages of the experiment; (c) adoption of a standard procedure for cleaning and preparing the glass surface; (d) maintenance of the viscometer bulb and capillary always in contact with the fluid by raising level immediately after each experiment; (e) adjustment of the position of the viscometer reproducibly; (f) measurement of the time of flow to within 1 msec. A full description of all parts of the system except the thermostat is given. The thermostat has been described separately. Examples are given illustrating both the accuracy of the technique and the importance of each and all of the above points.