Theory of a capillary viscometer

Problems in the theory of a capillary viscometer are considered where the test fluid flows through the capillary under a varying pressure drop. The effect of transients on the flow is evaluated.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 36, No. 4, pp. 689–694, April, 1979.     

Filtration of non-Newtonian liquids

An analysis of theoretical and experimental data relating to non-Newtonian filtration is presented. A filtration equation is proposed for suspensions.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 32, No. 6, pp. 1024–1033, June, 1977.     

Microfluidic rheology of non-Newtonian liquids

We investigate the rheological properties of a non-Newtonian glass-former liquid within lithographically defined microchannels in the range of temperatures above the vitrification region. The non-Newtonian behavior of the fluid, as evidenced by rotational rheology, is well described by a power law dependence of the viscosity on the shear rate. Taking into account such non-Newtonian character in the equations for the microfluidic motion, we relate the penetration dynamics into capillaries with the liquid rheological properties. The temperature dependence of the viscosity, determined over 1 order of magnitude in the temperature range 286-333 K and for shear rates between 0.07 and 1 s-1, can be described by a Vogel-Fulcher-Tamman law, consistent with the fragile nature of the investigated compound. Microfluidics is a promising analytical approach for the investigation of the rheology of non-Newtonian fluids within confined microenvironments.     

An absolute vibrating-wire viscometer for liquids at high pressures

The design and operation of a new vibrating-wire viscometer for the measurement of the viscosity of liquids at pressures up to 100 MPa are described. The design of the instrument is based on a complete theory so that it is possible to make absolute measurements with an associated error of only a few parts in one thousand. Absolute measurements of the viscosity of n-hexane are reported at 298.15 K at pressures up to 80 MPa. The overall uncertainty in the reported viscosity data is estimated to be ±0.5%, an estimate confirmed by the comparison of values of viscosity of slightly inferior accuracy.     

Autonomous microfluidic capillary system

The transport of minute amounts of liquids using microfluidic systems has opened avenues for higher throughput and parallelization of miniaturized bio/chemical processes combined with a great economy of reagents. In this report, we present a microfluidic capillary system (CS) that autonomously transports aliquots of different liquids in sequence: liquids pipetted into the service port of the CS flow unidirectionally through the various sections of the CS, which comprises a 15-pL reaction chamber, into the capillary pump. A CS can thus be operated by simply delivering the different samples to its service port. The liquid transport concept presented here is advantageous because the pumping and valving functions are integrated into the device by means of capillary phenomena, and it therefore does not require any external power supply or control device. Thus, arrays of CSs can easily be formed by cloning a functional CS. Alternatively, the flow of liquids in CSs can also be interactively tuned if desired by (i) forcing the evaporating of liquid out of the capillary pumps and (ii) by contacting a secondary, removable capillary pump to the embedded ones. We illustrate the possibilities of CSs by conducting a surface immunoassay for a cardiac marker, within 25 min, on an area of 100 x 100 microm2, using 16 sequential filling steps.     

Torsional piezoelectric crystal viscometer for compressed gases and liquids

A torsional piezoelectric crystal viscometer for compressed gases and liquids at temperatures to 600 K and a pressures to 70 MPa has been developed. Several torsional crystals were prepared from swept (electrolyzed) quartz to obtain a good performance at high temperatures. Measurements of the bandwidth of the crystal resonance curve were automated using an impedance analyzer. The viscometer was tested on compressed gaseous argon and methane at temperatures to 500 K and at pressures to 50 MPa. The measurements differ from accurate wide-range correlating equations by less than 2%.Paper presented at the Tenth Symposium on Thermophysical Properties, June 20–23, 1988, Gaithersburg, Maryland, U.S.A.     

Spreading of non-Newtonian liquids under the gravitational force

A technique is proposed for determining the rheological constants based on the analysis of the spreading of tall cylindrical samples under the gravitational force.     

Theory of the filtration of non-Newtonian liquids through porous media

The flow of a non-Newtonian liquid through soil is analyzed with an account of the channel shape.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 18, No. 6, pp. 1032–1037, June, 1970.     

The characterisation of foamed asphalt cement using a rotational viscometer

Warm mix asphalt using foaming technology is a widely used alternative to traditional Hot Mix Asphalt in the USA. However, there has been relatively limited research exploring the behaviour of the foamed asphalt cement, especially using traditional asphalt cement testing equipment. This research used the rotational viscometer to develop four new metrics that quantify the behaviour of foamed asphalt cement. These four metrics showed that increasing the foaming temperature increased the observed viscosity, but the initial observed viscosity decreased with lower asphalt binder grades. However, the point at which the observed viscosity crossed the actual viscosity increased with lower asphalt binder grades. Overall, the Wirtgen foamer had higher observed viscosity vs. the PTI foamer and provided a more robust foaming material. However, it is recommended that the AccuFoamer also be explored in future research, along with comparing laboratory produced foamed asphalt cement with field produced foamed asphalt cement.     

Generalization of the classical Rayleigh equation to several non-Newtonian liquids

Equations are derived that describe the change in the radius of a spherical gas inclusion in the Bingham, Ellis, Reiner-Rivlin, Shul'man, Kapur-Gupta,and Oswald de Vielle non-Newtonian liquids, as well as in a power-law liquid.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 35, No. 4, pp. 677–680, October, 1978.     

Shear rate dependence of the thermal conductivity in non-Newtonian liquids

The thermal conductivities of solutions of sodium carboxymethyl-cellulose (CMC), DMA, and albumin (myosin) have been measured at rest and at various shear rates.     

Measuring the refractive indices of liquids with a capillary tube interferometer

A theoretical analysis of the fringe pattern produced by a capillary tube interferometer is presented, which is expected to be two-beam interference, and a computer program to simulate the interference fringe pattern is established. By comparing the simulated fringe pattern and the experimental fringe pattern, the refractive index of the liquid can be given when the two fringes coincide best. The results of this method are close to those of the Abbe refractometer.     

The kinetics of capillary absorption of liquids in a constant magnetic field

The method and technique of experimental study is described with respect to the kinetics of capillary absorption of distilled water and a 10% aqueous solution of NaCl by quartz sand in a nonuniform magnetic field. The results of this experimental study are given.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 16, No.2, pp.270–275, February, 1969.     

Determination of cell viability in single or mixed samples using capillary electrophoresis laser-induced fluorescence microfluidic systems

The advent of high-efficiency microbial separations will have a profound effect on both chemistry and microbiology. For the first time, it appears that it may be possible to obtain qualitative and quantitative information on microbial systems with the accuracy, precision, speed, and throughput that currently is found for chemical systems. Recently it was suggested that an analytical separations-based approach for determining the viability of cells would be advantageous. The feasibility of such an approach is demonstrated using CE-LIF of two bacteria and yeast. The analytical procedures and figures of merit are outlined. High-throughput analyses and evaluation of microorganisms now appear to be possible.     

Development of a multichannel microfluidic analysis system employing affinity capillary electrophoresis for immunoassay

A six-channel microfluidic immunoassay device with a scanned fluorescence detection system is described. Six independent mixing, reaction, and separation manifolds are integrated within one microfluidic wafer, along with two optical alignment channels. The manifolds are operated simultaneously and data are acquired using a singlepoint fluorescence detector with a galvano-scanner to step between separation channels. A detection limit of 30 pM was obtained for fluorescein with the scanning detector, using a 7.1-Hz sampling rate for each of the reaction manifolds and alignment channels (57-Hz overall sampling rate). Simultaneous direct immunoassays for ovalbumin and for anti-estradiol were performed within the microfluidic device. Mixing, reaction, and separation could be performed within 60 s in all cases and within 30 s under optimized conditions. Simultaneous calibration and analysis could be performed with calibrant in several manifolds and sample in the other manifolds, allowing a complete immunoassay to be run within 30 s. Careful chip conditioning with methanol, water, and 0.1 M NaOH resulted in peak height RSD values of 3-8% (N = 5 or 6), allowing for cross-channel calibration. The limit of detection (LOD) for an anti-estradial assay obtained in any single channel was 4.3 nM. The LOD for the cross-channel calibration was 6.4 nM. Factors influencing chip and detection system design and performance are discussed in detail.     

The evaluation of non-Newtonian viscosity using a modified parallel-plate plastometer

A modified parallel-plate plastometer has been developed to measure the viscosity of rapid setting dental composite pastes. The theoretical treatment presented enabled the shear rates occurring in the specimen to be determined and, therefore, different materials to be compared. Five pastes were shown to be pseudoplastic power-law fluids each with uniqueK andn values.     

The use of a novel capillary flow viscometer for the study of the argon/carbon dioxide system

A novel capillary flow viscometer has been constructed which is ultimately intended to be used for the measurement of the viscosities of corrosive gases such as hydrogen chloride up to pressures of 0.1 MPa. In the process of checking the accuracy of the instrument, we have measured the viscosities of carbon dioxide and argon/carbon dioxide mixtures relative to standard argon viscosities in the temperature range 301 to 521 K. The carbon dioxide viscosities have previously been used to determine a viscosity average well depth for the gas, which is an essential parameter for the Chapman-Enskog analysis of the argon/carbon dioxide mixture viscosities as described here. The argon/carbon dioxide interaction viscosities which result from this analysis are compared to corresponding values calculated from the mixture viscosities of Kestin and Ro, and to Mason-Monchick calculations performed by Maitland et al., using the potential energy surface of Pack et al. The interaction viscosities are also used to calculate diffusion coefficients, which are compared to Mason-Monchick diffusion coefficients of Maitland et al. and to diffusion coefficients calculated from the mixture viscosities of Kestin and Ro. An inverted isotropic potential is used to calculate second virial coefficients, which are compared with experiment and with calculations based on the potential energy surface of Hough and Howard and of Parker et al.