Applied Rheology: Publications

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Horst Henning Winter
Bringing Eureka into Rheology at ARC08

Appl. Rheol. 18:6 (2008) 380-381

Cite this publication as follows:
Winter HH: Bringing Eureka into Rheology at ARC08, Appl. Rheol. 18 (2008) 380.

Helen J. Wilson, M. Paul Lettinga
Euromech Colloquium no. 492: Shear-banding Phenomena in Entangled Systems

Appl. Rheol. 18:6 (2008) 378-379

Cite this publication as follows:
Wilson HJ, Lettinga MP: Euromech Colloquium no. 492: Shear-banding Phenomena in Entangled Systems, Appl. Rheol. 18 (2008) 378.

Markus Greim
Rheology of Building Materials, 17th Conference, Univ. of Appl. Science, Regensburg, Mar 2008

Appl. Rheol. 18:6 (2008) 375-377

Cite this publication as follows:
Greim M: Rheology of Building Materials, 17th Conference, Univ. of Appl. Science, Regensburg, Mar 2008, Appl. Rheol. 18 (2008) 375.

Nick Triantafillopoulos, Bruce Schreiner, James Vaughn
Latex Carpet Compound Rheology

Appl. Rheol. 18:6 (2008) 64250 (9 pages)

This is a study of three-phase foam rheology to qualify penetration in to backing webs during frothed carpet compounds applications.Transient viscosity as a function of shear rate under a short time period is proposed to characterize flow of these compounds in response to a rapidly changing shear field during their application.We developed a fluid dynamic model that predicts the shear and pressure distributions in the compound during its processing in a metering nip based on process parameters and rheological results.We tested frothed compound formulations that are empirically known to be "penetrating" and "non-penetrating" based on the choice of soap (frothing surfactant). Formulated at the same froth density, penetrating to carpet backing compounds had large froth bubbles, relatively low transient shear viscosity and showed increasing foam breakdown due to shear when compared to non-penetrating compounds. Such frothed compounds readily collapse under shear and have relatively low dynamic stability, so the transition from a three-phased (air/aqueous/solid) to a twophased (water/solid) system occurs much easier and faster during application. The model predicts the shear rate development and a small difference in the pressure distributions in the applicator nip between these formulations, but reduction in drainage for the non-penetrating formulation.

Cite this publication as follows:
Triantafillopoulos N, Schreiner B, Vaughn J: Latex Carpet Compound Rheology, Appl. Rheol. 18 (2008) 64250.

Johanna Aho, Seppo Syrjala
Evaluation of different methods for determining the entrance pressure drop in capillary rheometry

Appl. Rheol. 18:6 (2008) 63258 (5 pages)

Two approaches for determining the entrance pressure drop in capillary rheometry were compared with low-density polyethylene and polystyrene melts as test fluids. Direct measurements with the orifice die were found to yield higher values for the entrance pressure drop, and hence lower values for the wall shear stress, than the Bagley correction method. This was postulated to be caused by the sticking of the melt to the wall of the outlet region of the orifice die. The additional pressure drop created in the outlet region of the orifice die, when the flowing material fills it completely, was also evaluated by means of numerical flow simulation.

Cite this publication as follows:
Aho J, Syrjala S: Evaluation of different methods for determining the entrance pressure drop in capillary rheometry, Appl. Rheol. 18 (2008) 63258.

Dimitri Feys, Ronny Verhoeven, Geert De Schutter
Extension of the Poiseuille formula for shear-thickening materials and application to Self-Compacting Concrete

Appl. Rheol. 18:6 (2008) 62705 (11 pages)

In practice, while placing concrete in a formwork by pumping, the pressure generated by the pump is not controlled. In order to enhance the safety on the worksite, and in view of the current economic and ecologic arguments, it would be useful to dispose of an equation able to predict pressure losses based on the rheological properties of the concrete and the pipe configuration. This paper describes the derivation of an extended version of the Poiseuille formula, for shear-thickening materials with a yields stress, described by the modified Bingham equation. This formula is applied to flow-tests with self-compacting concrete. The results prove the applicability of this extended Poiseuille formula, showing that the flow is occurring in laminar regime, with no significant wall slip.

Cite this publication as follows:
Feys D, Verhoeven R, DeSchutter G: Extension of the Poiseuille formula for shear-thickening materials and application to Self-Compacting Concrete, Appl. Rheol. 18 (2008) 62705.

Reinhardt Kotze, Rainer Haldenwang, Paul Slatter
Rheological characterisation of highly concentrated mineral suspensions using an Ultrasonic Velocity Profiling with combined Pressure Difference method

Appl. Rheol. 18:6 (2008) 62114 (10 pages)

The rheological behaviour of non-Newtonian, highly concentrated and non-transparent fluids used in industry have so far been analysed using commercially available instruments, such as conventional rotational rheometers and tube viscometers. When dealing with the prediction of non-Newtonian flows in pipes, pipe fittings and open channels, most of the models used are empirical in nature. The fact that the fluids or slurries that are used normally are opaque, effectively narrows down the variety of applicable in-line rheometers even further, as these instruments are normally based on laser or visible light techniques, such as Laser Doppler Anemometry. In this research, an Ultrasonic Velocity Profiling technique (UVP), in combination with a pressure difference (PD) measurement, was tested to provide in-line measurement of rheological parameters. The main objective of this research was to evaluate the capabilities of the UVP-PD technique for rheological characterisation of different concentrations of non-transparent non-Newtonian slurries. Kaolin, bentonite, Carboxymethyl Cellulose (CMC) and water solutions were used as model non-Newtonian mining slurries. Results determined by the UVP-PD method were compared with results obtained by off-line rheometry and in-line tube viscometry. The agreement between the UVP-PD method, tube viscometry and conventional rheometry was found to be within 15 % for all of the highly concentrated mineral suspensions investigated over a given range of shear rates.This method, if used in combination with a pressure difference technique (PD), has been found to have a significant potential in the development process of new in-line rheometers for process control within the mining industry.

Cite this publication as follows:
Kotze R, Haldenwang R, Slatter P: Rheological characterisation of highly concentrated mineral suspensions using an Ultrasonic Velocity Profiling with combined Pressure Difference method, Appl. Rheol. 18 (2008) 62114.


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