Rheometer

About: Rheometer is a research topic. Over the lifetime, 5759 publications have been published within this topic receiving 125849 citations.

Influence of temperature on the rheological behavior of whole araçá pulp (Psidium cattleianum sabine)

Abstract: The temperature effect on rheological behavior of whole araca pulp was investigated in this work. The pulp was processed in a depulper with a 1.5 mm screen to obtain a uniform consistency. The rheological measurements were carried out in a concentric cylinder Brookfield rheometer, with a small sample adapter and spindle SC4-27, in a shear rate range of 2.80–70 s−1. The whole pulp was properly described by the power law model and exhibited a shear thinning behavior. The viscosity decreased with an increase in temperature; however, the viscosity showed a tendency to increase at 60 °C. The Arrhenius model gave a good description of temperature effect on apparent viscosity of the pulp, where the activation energy (Ea) determined at a shear rate of 50 s−1 was 11.03 kJ mol−1.

Analysis of the rheological behavior and stability of 316L stainless steel–TiC powder injection molding feedstock

Abstract: An experimental rheological study has been performed to evaluate the influence of TiC addition on the rheological behavior and stability of 316L stainless steel powder injection molding (PIM) feedstock. The effects of TiC concentration, solid loading, shear rate and temperature were investigated via capillary rheometer method. The stability of feedstocks was evaluated quantitatively using “instability index”, which describes the threshold beyond which the variation of viscosity becomes unacceptable for PIM purposes. The results show that the rheological behavior of PIM feedstocks highly depends on the blend composition. The addition of TiC particles to the stainless steel powder increases the viscosity of feedstock at relatively low shear rates, i.e. 2000 s−1, the viscosity of composite feedstocks was lower than that of the mono-component SS feedstock due to the better particle packing efficiency. This article presents the rheological behavior of bimodal powder mixture of stainless steel and TiC powders prepared for PIM application. The influences of blend composition, i.e. the TiC concentration and solid loading, and the processing parameters, i.e. temperature and shear rate, are addressed.

Feasibility of optical coherence elastography measurements of shear wave propagation in homogeneous tissue equivalent phantoms

Abstract: In this work, we explored the potential of measuring shear wave propagation using optical coherence elastography (OCE) based on a swept-source optical coherence tomography (OCT) system. Shear waves were generated using a 20 MHz piezoelectric transducer (circular element 8.5 mm diameter) transmitting sine-wave bursts of 400 μs, synchronized with the OCT swept source wavelength sweep. The acoustic radiation force (ARF) was applied to two gelatin phantoms (differing in gelatin concentration by weight, 8% vs. 14%). Differential OCT phase maps, measured with and without the ARF, demonstrate microscopic displacement generated by shear wave propagation in these phantoms of different stiffness. We present preliminary results of OCT derived shear wave propagation velocity and modulus, and compare these results to rheometer measurements. The results demonstrate the feasibility of shear wave OCE (SW-OCE) for high-resolution microscopic homogeneous tissue mechanical property characterization.

Yield stress and viscoelastic properties of high internal phase ratio emulsions

Abstract: The rheology of high internal phase ratio oil-in-water emulsions was investigated using a controlled-stress rheometer. The dispersed-phase (oil) concentration was varied from 71.24 to 89.61% by volume. Three different types of rheological experiments were conducted for each emulsion, namely: steady shear, oscillatory shear, and creep/recovery experiments. All the emulsions investigated in this study possess a yield stress. The yield-stress values obtained from different rheological experiments for the same emulsion show good agreement with each other. The yield-stress value increases exponentially with an increase in the dispersed-phase concentration. The yield-stress data of this study can be described quite well with the Princen and Kiss equation for high internal phase ratio emulsions provided that the thickness of the interdroplet films is taken into account. For any given emulsion, the storage modulus, measured in the linear viscoelastic region, is found to be constant, independent of the frequency, indicating a solid-like behaviour. The value of the storage modulus increases with an increase in the dispersed-phase concentration. The storage modulus data are interpreted in terms of the Princen and Kiss equation.