Experimental investigation of electro-rheological properties of modeled vegetable oils

Abstract

Vegetable oil becomes polarized on oxidation and polymerization resulting in the formation of peroxide, triglycerides, etc. The quality and reusable state were investigated for sunflower, sesame, rice bran oil and model oil with the addition of oleic acid (2, 4 and 6 %) and antioxidants (citric and tert-Butyl hydroquinone-TBHQ). Excessive reclaims of cooking oil produce toxic by-products due to chemical breakdown that induce the production of polar compounds in oil. To determine the consumable fitness, variations of dielectric constant are observed at different temperatures (29 to 70°C) and frequencies (1 to 10 7 Hz) for the cooking oil. Physical parameters, such as viscosity and density associated with the saturated and unsaturated fatty acid, are also measured at different temperatures to determine the quality of oil. Dielectric constant and viscosity are correlated and analyzed using a newly developed equation with high correlation constant (R 2 =0.998) for oil added with citric acid. Oil added with 2-4 % of oleic acid is observed to have high determination coefficient (R 2 > 0.92). A lowest correlation (R 2 =0.6-0.7) was observed for the oil added with TBHQ. The present study also states that addition of TBHQ to oil does not impede oxidation reaction. Besides, even the shelf life of the oil could not be enhanced and may produce adverse effects in human health.

Empirical models to correlate the basic physical and chemical indices of modified rice bran and mustard oil

“…[14] Kinematic viscosities (η) of oil were measured using the ASTM D446 method. [13] Chemical parameters…”

“…When oil starts degrading, the chemicals present in it break down, which increases the polar compounds in the oil. [14] The ratio of the capacitance of a liquid to that of air gives the dielectric constant (ε r ) of the liquid, which is a measure of polar compounds. [7,15] Figure 1 illustrates the variation in the dielectric constant of the oil measured from 30°C to 75°C with steps of 5°C.…”

“…[14] Both dielectric constant and viscosity decrease non-linearly with temperature. Viscosity of oil represents the flow property, which can be related to the activation energies of movement and the orientation of dipoles with respect to temperature.…”

“…thermal energy, there is an increase in the dielectric constant value. [14] The quantification of PV is a direct index to estimate the quality of oil. Figure 3(c) illustrates the variation of PV with dielectric constant.…”

A new mathematical model for the viscosity of vegetable oils based on freely sliding molecules

“…here, K and n are constants, T ref is a reference temperature. Other expanded exponential forms of functions were reported as (Stanciu, 2012;Simion et al, 2014;Valantina et al, 2016):…”