Modeling the thixotropic behavior of structured fluids

Formulation Optimization, Rheological Characterization and Suitability Studies of Polyglucoside-based Azadirachta indica A. Juss Emollient Cream as a Dermal Base for Sun Protection Application

“…DC (3.33, 6.66, 9.99, 13.33 and 16.66%), ultrasonication time (3, 5, 7, 9 and 11 min), cavitation intensity (75.41, 150.82, 226.24, 301.65, 377.07 W/cm 2 ) and amplitude of sonication (30,40,50, 60, 70%) were standardized serially one after the other in this order by using previously reported standard values for synthesis of such formulations for optimization of the preceding parameters [10] . In each case, the minimum statistically significant particle size was the criterion for selection of the best value.…”

“…PI represents the extent of non-Newtonian fluid behaviour with values ranging from 0 to 1. It is inversely proportional to pseudoplasticity of fluids and is a measure of their thinning property [30] . A unique combination of high k and low PI represent its time independent behaviour and ensures good dermal spreadability.…”

Performance of an elasto-viscoplastic model in some benchmark problems

“…The elastic strain tensor field γ e − γ e,n is measured with respect to the neutral configuration γ e,n , which corresponds to the configuration that the material in its present microstructural state would eventually acquire if the stress were set to zero (de Souza Mendes 2009, 2011. It is obtained dividing τ 1 by the scalar field of the elastic modulus G(λ):…”

“…Ahmadpour and Sadeghy (2013) presented an exact solution for a thixotropic fluid in a laminar flow inside a tube, using the Houska model. The present work presents some numerical results of benchmark geometries using elasto-viscoplastic thixotropic fluids modeled by the constitutive equations developed in de Souza Mendes (2009) andde Souza Mendes (2011). The equation is based on the Jeffreys (or Oldroyd-B) analog model, with variable coefficients, which depend on the structure level of the material, which in turn is a function of the stress level.…”

Evaluation of Measurement Methods of Waxy Crude Oil Thixotropy

“…Macroscopic experiments are usually used to investigate the thixotropy of gelled fluids. Among the numerous studies on the thixotropy of waxy crude oils based on macroscopic experiments, Paulo [5] proposed a novel Maxwell-type viscoelastic model that avoided the drawbacks in the previously published Maxwell-type models. This model can predict the flow behavior accurately when the shear rate or the shear stress undergoes an abrupt change.…”