Applied Rheology: Publications

Appl Rheol online available publications for selected issue

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Marianna Kontopoulou, Marie-Claude Heuzey, Frej Mighri
Symposium on Rheology of Complex Fluids and Honorary Symposium for Pierre Carreau during the 66th Canadian Chemical Engineering Conference

Appl. Rheol. 26:6 (2016) 53-54

Cite this publication as follows:
Kontopoulou M, Heuzey M, Mighri F: Symposium on Rheology of Complex Fluids and Honorary Symposium for Pierre Carreau during the 66th Canadian Chemical Engineering Conference, Appl. Rheol. 26 (2016) 53.

Hildegard Lyko
International Workshop Dispersions Analysis and Materials Testing (LUM 2016)

Appl. Rheol. 26:6 (2016) 49-52

Cite this publication as follows:
Lyko H: International Workshop Dispersions Analysis and Materials Testing (LUM 2016), Appl. Rheol. 26 (2016) 49.

Tatsiana Savitskaya, Ivan Reznikov, Dmitry Grinshpan
Rheological Behavior of Lignin Based Dispersions Intended for Composite Fuel Production

Appl. Rheol. 26:6 (2016) 63476 (7 pages)

Dispersions of acid hydrophobized hydrolysis lignin in light crude oil, industrial oil, and diesel fuel were found to demonstrate the transition from Newtonian to non-Newtonian behavior with shear-thinning and thixotropy within the increase in lignin concentration. Lignin-in-diesel fuel dispersions were shown to have the smallest apparent viscosity while lignin-in-industrial oil dispersions have the highest one and the sharpest drop of viscosity with shear rate increasing. At the same time, relative viscosity demonstrates the inverse dependence: It is highest for lignin-in-diesel fuel suspensions. Calculation of parameters based on microrheological model of elastic flocs with generalized Casson equation allowed determining of the parameters k and A that describe hydrodynamic interaction between separated particles and their aggregates under flow, parameter FA, characterizing the force impeding the break of aggregates and numbers of particles in the floc for different systems as the dependence of shear stress. The explanation based on a higher affinity of diesel fuel to lignin unlike industrial oil and light crude oil as dispersing medium has been given.

Cite this publication as follows:
Savitskaya T, Reznikov I, Grinshpan D: Rheological Behavior of Lignin Based Dispersions Intended for Composite Fuel Production, Appl. Rheol. 26 (2016) 63476.

Katja A. Fröhlich, Eleni Mitrentsis, Frank Clemens, Botho Hoffmann, Véronique Michaud, Thomas Graule
Assessment of the Dispersion Quality of refractive index-matched nanodispersions

Appl. Rheol. 26:6 (2016) 65050 (10 pages)

Dispersion quality has a large influence on the resulting properties of filled polymers, hybrids and nanocomposites in general. Reducing the van der Waals forces and therefore, matching the refractive index between the filler and the matrix should improve dispersion in hybrid materials. However, in this case the usual light-based techniques cannot be used to assess dispersion quality. In this work, dispersions containing silica nanoparticles and a solvent mixture of 1-butanol and benzyl alcohol were analysed by rheological methods. The refractive index of the solvent was changed by varying the mixing ratio, and thus the effect of index difference on the filler-matrix interaction was investigated. In agreement with theory, a stronger gel network was observed when the refractive index of filler and solvent were matched. If the difference in refractive index of the two materials became too large, particles and solvent interaction was reduced, and agglomerates were formed. This resulted in a weaker gel network.

Cite this publication as follows:
Frohlich KA, Mitrentsis E, Clemens F, Hoffmann B, Michaud V, Graule T: Assessment of the Dispersion Quality of refractive index-matched nanodispersions, Appl. Rheol. 26 (2016) 65050.

Sven Pieper, Hans-Joachim Schmid
Guard ring induced distortion of the steady velocity profile in a parallel plate rheometer

Appl. Rheol. 26:6 (2016) 64533 (7 pages)

The shape and fracture of the free surface frequently limits the measuring range and impedes the use of optical velocimetric techniques in parallel plate and cone plate setups. To prevent this, various kinds of edge guards are often employed. In the present study, we elucidate how an edge guard distorts the steady velocity profile in a parallel plate setup. To this end, we analyzed the velocity field of a strongly shear-thinning fluid, a Newtonian fluid and a set of suspensions via particle image velocimetry in a parallel plate device. Several guard ring sizes were studied. The distortion is described by a simple three parameter model. These parameters are mostly constant for different fluids and suspensions with particle volume fractions below 45%. With increasing radius, the guard ring.s influence approaches a limiting value that we attribute to the influence of the fluid surrounding the gap. Our results indicate a limiting ratio of the difference between plate radius and guard to gap size that should always be exceeded. In the presence of a guard ring, even Newtonian fluids do not exhibit a constant shear rate for most radial distances within the gap. This distortion of the velocity field challenges the simple superposition approach of unguarded device and guard influence that is prevalent in the literature.

Cite this publication as follows:
Pieper S, Schmid H: Guard ring induced distortion of the steady velocity profile in a parallel plate rheometer , Appl. Rheol. 26 (2016) 64533.

Hoseini Maryam, Haghtalab Ali, Family Navid
Influence on compounding methods on rheology and morphology of linear low density polyethylene/poly(lactic acid)

Appl. Rheol. 26:6 (2016) 64746 (8 pages)

Linear low density polyethylene (LLDPE)/poly lactic acid (PLA) blends were prepared via different melt mixing methods. The effects of various blend compositions and two mixing methods on morphological and rheological behavior of the blends were studied. Scanning electron microscope (SEM) was used to investigate morphology behavior of the blends. The rheological studies illustrated that all samples presented shear thinning behavior and the PLA-rich blends exhibited a Newtonian region. It was found from the rheological measurements that the LLDPE/PLA (75/25 w/w) prepared by batch mixer exhibited higher values of storage modulus and complex viscosity, which is in agreement with the morphology results. In addition, using the different mixing methods, significant differences in the morphological results for the LLDPE/PLA (50/50 w/w) blend were observed. Finally, the results showed that the blends prepared by batch mixer exhibited better morphology, higher storage modulus, and complex viscosity.

Cite this publication as follows:
Maryam H, Ali H, Navid F: Influence on compounding methods on rheology and morphology of linear low density polyethylene/poly(lactic acid), Appl. Rheol. 26 (2016) 64746.

Adam S Burbidge, Julie A. Y. Cichero, Jan Engmann, Catirona M. Steele
''A day in the life of the fluid bolus'': An introduction to fluid mechanics of the oropharyngeal phase of swallowing with particular focus on dysphagia.

Appl. Rheol. 26:6 (2016) 64525 (10 pages)

By following the path of a liquid bolus, from the oral preparatory phase to the esophagus, we show that a few fundamental concepts of fluid mechanics can be used to better understand and assess the importance of bolus viscosity during human swallowing, especially when considering dysfunctional swallowing (dysphagia) and how it can be mitigated. In particular, we highlight the important distinction between different flow regimes (i.e. viscosity controlled versus. inertia controlled flow). We also illustrate the difference between understanding bolus movements controlled by a constant force (or pressure) and those controlled by a constant displacement (or velocity). We limit our discussion to simple, Newtonian liquids where the viscosity does not depend on the speed of flow. Consideration of non-Newtonian effects (such as shear thinning or viscoelasticity), which we believe play an important part in human swallowing, requires a sound grasp of the fundamentals discussed here and warrants further consideration in its own right.

Cite this publication as follows:
Burbidge AS, Cichero JAY, Engmann J, Steele CM: ''A day in the life of the fluid bolus'': An introduction to fluid mechanics of the oropharyngeal phase of swallowing with particular focus on dysphagia., Appl. Rheol. 26 (2016) 64525.


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