Viscosity Measurements of Liquid Toluene at Low Temperatures Using a Dual Vibrating-Wire Technique

Abstract

A recently developed dual vibrating-wire technique has been used to perform viscosity measurements of liquid toluene in the temperature range 213 K [ T [ 298 K, and at pressures up to approximately 20 MPa. The results were obtained by operating the vibrating-wire sensor in both forced and free decay modes. The estimated precision of the viscosity measurements, in either mode of operation, is ± 0.5%, for temperatures above or equal to 273 K, increasing with decreasing temperature up to ± 1% at 213 K. The corresponding overall uncertainty is estimated to be within ± 1% and ± 1.5%, respectively.

Effect of temperature, concentration, and pressure on the viscosity of pomegranate and pear juice concentrates

“…As shown in Table 4, good agreement (AAD = 0.63% for pure water and 0.44% for toluene) was obtained between the present measurements and the values calculated with IAPWS standard equation and reference data (Assael et al (1991); Assael et al, 1992 andCaetano et al, 2004). This excellent agreement between the present data and IAPWS standard for pure water and reference data for toluene confirms the reliability and high accuracy of the measurements for pomegranate and pear juices and gives us an assurance that our instrument is functioning correctly.…”

Validation of a Vibrating-Wire Viscometer: Measurements in the Range of 0.5 to 135 mPa·s

“…Therefore, an analysis of the electrical impedance of the wire, measured along a range of frequencies containing its resonance frequency, enables the determination of the velocity resonance curve for the transverse oscillations of the wire. 10 It should be noted, however, that the electronic setup and circuitry used for the present measurements differ from those previously described, which were utilized in our first measurements of the viscosity of diisodecylphthalate. 4 These incorporated a resistance, including a variable resistor, connected in series with the sensor, aimed at enabling a continuous change of the current.…”

“…Parameters C, L p , L s , G, and R s in eq 7, which are directly related 10 to the hydrodynamic model equations, are determined by fitting the experimental resonance curve. The velocity resonance frequency, ω r , and the half-width of the resonance curve, ∆ω ) ω + -ω -, are calculated from the parallel circuit elements; therefore, the viscosity of the fluid surrounding the wire can be calculated by resorting to the hydrodynamic model equations (eqs 1 and 2) once the cell parameters and the fluid density are known.…”

DSPIC-Based Impedance Measuring Instrument

“…They can also be used to measure sensor's outputs that translate physical quantities into electrical impedance [1].…”