Applied Rheology: Publications

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Martin Zatloukal
Novel Trends in Rheology V

Appl. Rheol. 23:5 (2013) 312-313

Cite this publication as follows:
Zatloukal M: Novel Trends in Rheology V, Appl. Rheol. 23 (2013) 312.

Ulrich Alexander Handge
Joint Symposium of the German Rheological Society and the Polymer Processing Society (PPS-29) Fundamental and Applied Rheology

Appl. Rheol. 23:5 (2013) 310-311

Cite this publication as follows:
Handge UA: Joint Symposium of the German Rheological Society and the Polymer Processing Society (PPS-29) Fundamental and Applied Rheology, Appl. Rheol. 23 (2013) 310.

Claus Greve Madsen, Johanna Aho, David Wray Featherston, Stefania Baldursdottir
Rheology: A cross-disciplinary technology evolving to take on new challenges (22nd Nordic Rheology Conference 2013)

Appl. Rheol. 23:5 (2013) 309-310

Cite this publication as follows:
Madsen CG, Abo J, Featherston DW, Baldursdottir S: Rheology: A cross-disciplinary technology evolving to take on new challenges (22nd Nordic Rheology Conference 2013), Appl. Rheol. 23 (2013) 309.

T. Schweizer
Introduction to Polymer Rheology (M.T. Shaw)

Appl. Rheol. 23:5 (2013) 266-267

Cite this publication as follows:
Schweizer S: Introduction to Polymer Rheology (M.T. Shaw), Appl. Rheol. 23 (2013) 266.

Wolfram Schmidt, H. J. H. Brouwers, Hans-Carsten Kuhne, Birgit Meng
The working mechanism of starch and diutan gum in cementitious and limestone dispersions in presence of polycarboxylate ether superplasticizers

Appl. Rheol. 23:5 (2013) 52903 (12 pages)

Polysaccharides provide high potential to be used as rheology modifying admixtures in mineral binder systems for the construction industry such as concrete or mortar. Since superplasticizers have become state of technology, today, concrete is more and more adjusted to flowable consistencies. This often goes along with the risk of segregation, which can be effectively avoided by adding stabilising agents supplementary to superplasticizers. Stabilising agents are typically based on polysaccharides such as cellulose, sphingan gum, or starch. Starch clearly distinguishes in its effect on rheology from other polysaccharides, mainly due to the strong influence of amylopectin on the dispersion and stabilisation of particles. Based on rheometric investigations on cementitious and limestone based dispersions with different volumetric water to solid ratios, the mode of operation of modified potato starch is explained in comparison to a sphingan gum. It is shown that the stabilising effect of starch in a coarsely dispersed system is mainly depending upon the water to solid ratio and that above a certain particle volume threshold starch mainly affects the dynamic yield stress of dispersions, while plastic viscosity is affected only to a minor degree. Sphingans operate more independent of the particle volume in a coarsely dispersed system and show significantly higher effect on the plastic viscosity than on the yield stress. In systems incorporating superplasticizers, influences of both stabilising agents on yield stress retreat into the background, while both observed polysaccharides maintain their effect on the plastic viscosity.

Cite this publication as follows:
Schmidt W, Brouwers HJH, Kuhne H-C, Meng B: The working mechanism of starch and diutan gum in cementitious and limestone dispersions in presence of polycarboxylate ether superplasticizers, Appl. Rheol. 23 (2013) 52903.

M. Soutrenon, V. Michaud, J-A.E. Manson
Influence of processing and storage on the shear thickening properties of highly concentrated monodisperse silica particles in polyethylene glycol

Appl. Rheol. 23:5 (2013) 54865 (9 pages)

The shear thickening behavior of concentrated suspensions can be exploited to dissipate energy during impact or shear loading. To preserve the consistency of the thickening behavior in practical applications, particle concentration, and dispersion should be kept within very close bounds over time. In this article, we analyze the influence of the processing methods and storage conditions on the rheological properties of shear thickening fluids (STF) based on monodisperse suspensions of silica particles in polyethylene glycol. Particle dispersion linked to processing method and time strongly influences the value of the critical shear rate and storage in contact with air and humidity is responsible for a change in particle concentration. Encapsulating the suspensions in silicone is proposed as a solution to preserve their rheological properties over time.

Cite this publication as follows:
Soutrenon M, Michaud V, Manson JAE: Influence of processing and storage on the shear thickening properties of highly concentrated monodisperse silica particles in polyethylene glycol, Appl. Rheol. 23 (2013) 54865.

S. Noroozi, S. Tavangar, S.H. Hashemabadi
CFD Simulation of Wall Impingement of Tear Shape Viscoplastic Drops Utilizing OpenFOAM

Appl. Rheol. 23:5 (2013) 55519 (13 pages)

The main objective of this study is to get insight into the dynamic behavior of viscoplastic drop in impingement process in which the Capillary number is greater than one. In numerical analysis, Volume Of Fluid (VOF) approach was used for capturing the liquid-gas interface. Two different drop shapes (spherical and tear shapes) were used to investigate the drop morphology in an impingement process. According to the results, the numerical results concerning the tear shape drop showed proper agreement with experimental reports (mean deviation of 16 %) in different impact velocities. The flow field was discussed during the impact process in terms of its effect on apparent viscosity and spreading length. Influence of contact angle, consistency, power law index, and surface tension variations on spreading parameter (ratio of contact diameter on the substrate to equivalent initial drop diameter) were investigated. Furthermore, three different rheological models (consisting of Herschel-Bulkley, Casson, and Robertson-Stiff) were employed to study the effects of rheological models on simulation outcomes.

Cite this publication as follows:
Noroozi S, Tavangar S, Hashemabadi S: CFD Simulation of Wall Impingement of Tear Shape Viscoplastic Drops Utilizing OpenFOAM, Appl. Rheol. 23 (2013) 55519.

Shuyun Wu
Shear and Elongational Rheology of Partially Hydrolyzed Polyacrylamide Used for EOR

Appl. Rheol. 23:5 (2013) 53800 (7 pages)

Rheological properties are one of the primary considerations in selecting a fluid for using in chemical flooding enhanced oil recovery (EOR) operations. In this work, the rheological behavior of partially hydrolyzed polyacrylamide (HPAM) used for EOR was characterized by different techniques like steady shear flow and uniaxial elongation in capillary breakup experiments. Particular attention was focused on the main parameters affecting flow behavior of solutions, such as polymer concentration, molecular weight and molecular weight distribution. The shear rate dependence of viscosity for HPAM solutions could be described by the Carreau model. Elastic model was used to fit the rheological results obtained by transient uniaxial extensional technique, which enabled to evaluate relaxation time. The results indicated that the elasticity of HPAM solutions was dominated by molecular weight. Shear viscosity at higher shear rates was mainly influenced by polymer concentration, which was not an important factor determining relaxation time. For HPAM solutions, increasing of molecular weight distribution led to a decrease in shear viscosity, and vice versa for elongational viscosity and relaxation time. In addition, it was found that there was direct proportional relationship between first normal stress difference and elongational viscosity.

Cite this publication as follows:
Wu S: Shear and Elongational Rheology of Partially Hydrolyzed Polyacrylamide Used for EOR, Appl. Rheol. 23 (2013) 53800.


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