Applied Rheology: Publications

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Heinz Konietzky
1st International PFC-Symposium on Numerical Modeling in Micromechanics via Particle Methods

Appl. Rheol. 12:6 (2002) 314-315

Cite this publication as follows:
Konietzky H: 1st International PFC-Symposium on Numerical Modeling in Micromechanics via Particle Methods, Appl. Rheol. 12 (2002) 314.

Patrick B. Warren
5th Liquid Matter Conference

Appl. Rheol. 12:6 (2002) 312-313

Cite this publication as follows:
Warren PB: 5th Liquid Matter Conference, Appl. Rheol. 12 (2002) 312.

Giovanni De Cesare
Third International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering (3rd ISUD)

Appl. Rheol. 12:6 (2002) 309-311

Cite this publication as follows:
DeCesare G: Third International Symposium on Ultrasonic Doppler Methods for Fluid Mechanics and Fluid Engineering (3rd ISUD), Appl. Rheol. 12 (2002) 309.

I. Eriksson, U. Bolmstedt, A. Axelsson
Evaluation of a helical ribbon impeller as a viscosity measuring device for fluid foods with particles

Appl. Rheol. 12:6 (2002) 303-308

The traditional methods of measuring viscosity with rotational viscometers, i.e. cone-plate and concentric cylinder systems, are often not suitable for suspensions. To be able to measure viscosity on suspensions mixer viscometers have been developed. In this study a new design of a helical ribbon impeller has been evaluated and the Metzner-Otto approach has been used to calibrate the impeller. Different kinds of food products were studied. The Metzner-Otto parameter obtained from tomato products was lower than those obtained from starch products. The study showed that the Metzner-Otto parameter varied but seemed rather to be dependent on the composition of the food material than on the flow behaviour index. The impeller could handle high concentration of quite large particles. This type of helical ribbon impeller viscometer is thus recommended for rheological studies of suspensions with high concentration of particles.

Cite this publication as follows:
Ericksson I, Bolmstedt U, Axelsson A: Evaluation of a helical ribbon impeller as a viscosity measuring device for fluid foods with particles, Appl. Rheol. 12 (2002) 303.

Dimiter Hadjistamov
Viscoelastic Behavior of Disperse Systems with Silicone Oil and Different Fillers

Appl. Rheol. 12:6 (2002) 297-302

The rheological behavior of model suspensions with the silicone oil M20000 and different concentrations of Cab-o-sil TS 720 resp. Durcal 5 are compared. The increase of the Cab-o-sil concentration changes the flow behavior of the suspension from shear-thinning, to pseudoplastic, and to plastic flow behavior. The first normal stress difference rises at the same time at certain shear rate. The disperse systems with Durcal 5 keep the structural viscous behavior of the silicone oil even with a filler concentration of 40.5 wt%. The dependence of the first normal stress difference on shear rate represents for suspensions with Durcal 5 only one straight line with a slope of n = 2. The normal stress has double the amount of the silicone oil M20000 at given shear rate and is independent of the used Durcal 5 concentration. It was established that suspensions with the silicone oil M20000 have a first normal stress difference that can, depending on the filler type, either increase (with Cab-o-sil TS 720) or decrease (with Durcal 5) at certain shear stress with increasing filler concentration. It is to be supposed that the decrease of the normal stress at a given shear stress, with increasing Durcal concentration, is a softening effect, caused by the filler.

Cite this publication as follows:
Hadjistamov D: Viscoelastic Behavior of Disperse Systems with Silicone Oil and Different Fillers, Appl. Rheol. 12 (2002) 297.

Haifa El-Sadi, Nabil Esmail
The Effect of Yellowing Inhibitor Total Charge on The Rheology of Paper Coating

Appl. Rheol. 12:6 (2002) 289-296

New compounds, called inhibitors, provide anti-yellowing effect for mechanical pulps and papers, when added to the coating formulation. The rheology of coating mixtures, which contain clay, ground calcium carbonate, starch, latex, inhibitors and other minor additives, affects to a certain extent the final quality of the coated paper. The purpose of this work is to investigate the effect of the total weight charge of inhibitors, when present between coating color ingredients, on the thixotropy and visco-elasticity of the mixture and other rheological properties. We also study the degree of interaction between inhibitor and coating ingredients using Transmission Electron Microscope (TEM) and water retention measurements. For the industrially preferred inhibitor system of low RS/UVA ratio and high total charge the coating formulation will have a significant increase in the general value of viscosity and a clear and profound shear-thinning behavior. Under the desired conditions of higher total charge the coating formulation acquires significant thixotropic behavior. A higher level of energy is required to coat such formulation. The elastic modulus increases with frequency. This rise in the elastic modulus reveals the increasing interaction between particles in the coating formulation. The total charge does not affect the resistance of a coating color to the applied stress. The coating color with low total charge has the strongest water holding capability decreasing with increasing total charge.

Cite this publication as follows:
El-Sadi H, Esmail N: The Effect of Yellowing Inhibitor Total Charge on The Rheology of Paper Coating, Appl. Rheol. 12 (2002) 289.

Melissa J.Daniels Pearce, Danielle D.Bellmer
Data Variability in Rheological Measurement of Semi-Solid Foods: Effects of Loading Normal Force

Appl. Rheol. 12:6 (2002) 282-288

Previous studies involving rheological measurement of semi-solid foods have reported a large amount of data variability, but have focused little on understanding the cause of such variability. This project examined whether differences in normal force have an effect on the variability of rheological measurements. Experimental methods focused on error introduced during sample loading; specifically whether normal force application during loading influenced the storage (G.) and loss (G.) moduli of semi-solid and liquid foods. Samples were loaded to 5 or 20 N between the parallel plates of a TA-1000N rheometer and tested immediately. For all semi-solid products tested, normal force application during sample loading did significantly affect oscillatory parameters, with G. and G. measurements increasing up to 50 % with greater normal force. However, loading normal force did not significantly influence the parameters measured for the liquid sample. This suggests that differences in normal force during loading could be a significant source of data variability during rheological measurement of semi-solid products.

Cite this publication as follows:
Pearce MAD, Bellmer DD: Data Variability in Rheological Measurement of Semi-Solid Foods: Effects of Loading Normal Force, Appl. Rheol. 12 (2002) 282.

Marco Dressler
Computational Rheology (R.G. Owens, T.N. Phillips)

Appl. Rheol. 12:6 (2002) 280-281

Cite this publication as follows:
Dressler M: Computational Rheology (R.G. Owens, T.N. Phillips), Appl. Rheol. 12 (2002) 280.


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