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Arild Saasen, Jan David Ytrehus
Rheological Properties of Drilling Fluids - Use of Dimensionless Shear Rates in Herschel-Bulkley MoDe.S and Power-Law MoDe.S

Appl. Rheol. 28:5 (2018) 54515 (10 pages)

An approach of Nelson and Ewoldt [Soft Matter 13 (2017) 7578] to create a viscosity model of the Herschel-Bulkley type in order to use only parameters with the potential of containing fluid information has been extended to be applied to drilling fluids using current industry standard procedures. The commonly used Herschel-Bulkley consistency parameter k is found inadequate in describing fluid properties properly as it has a unit dependent on n. Hence, the model is not optimum for digitalisation. The Herschel- Bulkley model is re-written and base its parameters directly on the yield stress and the additional or surplus shear stress at a pre-determined shear rate relevant for the flow situation to be considered. This approach is also applicable for Power-Law moDe.S.

Cite this publication as follows:
Saasen A, Ytrehus JD: Rheological Properties of Drilling Fluids - Use of Dimensionless Shear Rates in Herschel-Bulkley Models and Power-Law Models, Appl. Rheol. 28 (2018) 54515.

Fahmida Ashraf, Taqi Ahmad Cheema, Cheol Woo Park
The Impact of Pulsatile Spiral Flow on the Wall Deformation Characteristics and Low-De.Sity Lipoproteins Accumulation in the Aorta

Appl. Rheol. 28:3 (2018) 35702 (10 pages)

Spiral blood flow in the aorta is helpful in maintaining the stability of flow, reduction in lateral forces, turbulence near walls, and shear stress index. Thus, it helps in the prevention of diseases, such as atherosclerosis and atherogenesis, in the aortic arch because of the reduced accumulation of low-De.Sity lipoproteins (LDLs). To investigate the actual physics behind the aforementioned phenomenon, we conducted a fluid-structure interaction (FSI)-based numerical simulation of the threedimensional aortic arch model under the influence of a pulsatile spiral flow. Spiral flow was introduced through the use of a mapping methodology between a spiral graft model and aortic model. The physics of time dependent pulsatile spiral turbulent flow was coupled with the structural mechanics of the aorta by using the FSI method. Results showed that the exterior interface of the aortic arch tends to rupture under the actions of centrifugal forces and secondary flow counter-rotating vortices in addition to applied pressure forces. Under systolic and diastolic conditions, the interior and exterior interfaces of the aortic arch both had small displacement, thus showing the insignificant role of velocity gradients in wall deformation. Moreover, LDL accumulation in the aorta under the influence of pulsatile spiral flow has been investigated using particle tracing methodology. The LDLs were evenly distributed in the aorta because of the influence of spiral flow. This result shows that spiral flow can contribute to the elimination of threats from diseases, such as atherosclerosis and atherogenesis.

Cite this publication as follows:
Ashraf F, Cheema TA, Park CW: The Impact of Pulsatile Spiral Flow on the Wall Deformation Characteristics and Low-Density Lipoproteins Accumulation in the Aorta, Appl. Rheol. 28 (2018) 35702.

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

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

Linear low De.Sity 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.

Burkhard Duenweg, J. Ravi Prakash
Hydrodynamic Fluctuations in Soft-Matter Simulations

Appl. Rheol. 26:5 (2016) 51-52

Cite this publication as follows:
Duenweg B, Prakash JR: Hydrodynamic Fluctuations in Soft-Matter Simulations, Appl. Rheol. 26 (2016) 51.

M. D. Inocente Domingos, A. L. Faxina
High-temperature properties and modeling of asphalt binDe.S modified with SBR copolymer and PPA in the multiple stress creep and recovery (MSCR) test

Appl. Rheol. 26:5 (2016) 53830 (9 pages)

The main objectives of this paper are to (i) study the rutting performance of asphalt binDe.S modified with styrene butadiene rubber (SBR) copolymer, polyphosphoric acid (PPA) and SBR+PPA, (ii) quantify the percent recoveries R and the nonrecoverable compliances Jnr in the multiple stress creep and recovery (MSCR) test, and (iii) indicate the best formulations in terms of rutting performance. All these formulations have the same high-temperature performance grade in the SuperpaveĀ® specification (PG 76-xx). The Burgers model was used to fit the laboratory data and the parameter GVwas obtained from the model. The degrees of improvement in the R and the Jnr values after binder modification are higher for the AC+SBR+PPA and the AC+PPA than for the AC+SBR and the results are slightly better for the AC+SBR+PPA. The use of longer creep and recovery times led to increases in the stress sensitivity of the modified asphalt binDe.S and in their rutting potential (higher Jnr values and lower R values) and these effects are more pronounced for the AC+SBR. The AC+SBR+PPA was identified as the best formulation in terms of elastic response and susceptibility to rutting, followed by the AC+PPA and the AC+SBR.

Cite this publication as follows:
InocenteDomingos MD, Faxina AL: High-temperature properties and modeling of asphalt binders modified with SBR copolymer and PPA in the multiple stress creep and recovery (MSCR) test, Appl. Rheol. 26 (2016) 53830.

Peter Fischer
Traffic Flow Dynamics - Data, MoDe.S, and Simulation (Martin Treiber and Arne Kesting)

Appl. Rheol. 26:1 (2016) 11-11

Cite this publication as follows:
Fischer P: Traffic Flow Dynamics - Data, Models, and Simulation (Martin Treiber and Arne Kesting), Appl. Rheol. 26 (2016) 11.

M. Bueno, A. Garcia, M.N. Partl
Applications of Strain-Rate Frequency Superposition for Bituminous BinDe.S

Appl. Rheol. 25:6 (2015) 65980 (12 pages)

Nonlinear viscoelastic behavior of bitumen has a determinant effect on the performance of asphalt roads suffering permanent deformation due to traffic loads. Up to know, conventional rheological characterization of bituminous binDe.S, such as the time-temperature superposition (TTS) method, only addresses the linear response of this material without considering the application of high strain amplitudes. The strain-rate frequency superposition (SRFS) is an analogous technique that can experimentally determine the flow behavior from nonlinear oscillatory shear experiments. This method was originally applied to soft materials in order to study the slow relaxation process of particular systems by shifting to higher frequencies the behavior usually found at very low frequencies during conventional measurements. In this work, the feasibility of the SRFS method for assessing the rheological properties of bituminous binDe.S has been evaluated. Oscillatory shear measurements accomplished at different constant shear strain ampliture rates (γ. = ωγ0) and test temperatures allowed analysing the influence of the nonlinear behavior of unmodified and polymer modified bitumen on their viscoelastic responses. The results showed that displacements in the responses due to different strain rates were not so significant as to extend the frequency range further than in conventional measurements. Differences in responses between both techniques were mainly observed for polymer modified binDe.S, especially to high strain amplitudes which usually involve nonlinear behaviour. In addition, master curves obtained with constant strain rates, i.e. taking into account nonlinear response of the material, showed similar results to those constructed by using conventional methods with constant strain amplitude. From these results, a closer comprehension of the large deformations generated in asphalt pavements can be achieved by studying the nonlinear viscoelastic properties of the bituminous binder.

Cite this publication as follows:
Bueno M, Garcia A, Partl M: Applications of Strain-Rate Frequency Superposition for Bituminous Binders, Appl. Rheol. 25 (2015) 65980.

Flavio H. Marchesini, Monica F. Naccache, Aline Abdu, Alexandra A. Alicke, Paulo R. De.Souza Mendes
Rheological characterization of yield-stress materials: Flow pattern and apparent wall slip

Appl. Rheol. 25:5 (2015) 53883 (10 pages)

An experimental and numerical investigation of the rotational rheometry of yield-stress materials is performed, using waterbased Carbopol dispersions. The flow and fluid characterization in different rheometer geometries, namely the smooth Couette, the grooved Couette, and the vane-in-cup are analyzed. The bi-dimensional flow governing equations are solved numerically, using the finite volume method and Fluent software (Ansys Inc.). The viscoplastic behavior of Carbopol dispersions is modeled using the Generalized Newtonian constitutive equation with the regularized viscoplastic viscosity function proposed by De.Souza Mendes and Dutra [1], herein called SMD function. The flow pattern and the presence of apparent wall slip in rheometric measurements of yield-stress materials are investigated and discussed.

Cite this publication as follows:
Marchesini FH, Naccache MF, Abdu A, Alicke AA, deSouzaMendes PR: Rheological characterization of yield-stress materials: Flow pattern and apparent wall slip, Appl. Rheol. 25 (2015) 53883.

Rudolf Hampl, Otakar Vacin, Martin Jasso, Jiri Stastna, Ludo Zanzotto
Modeling of tensile creep and recovery of polymer modified asphalt binDe.S at low temperatures

Appl. Rheol. 25:3 (2015) 34675 (8 pages)

The creep and recovery of asphalt modified with Elvaloy 4170 and polyphosphoric acid were studied at low temperatures, by inductive phenomenological methods. Two moDe.S of the tensile compliance function were investigated. Both moDe.S were derived from the linear viscoelastic retardation spectra and successfully used for the description of the creep and recovery tests in the studied asphalt binDe.S. Large effects due to oxidative aging in a rolling thin film oven were found from the recovered compliance function recorded in a bending beam rheometer at a temperature of - 20 C. The studied compliance function moDe.S worked well at higher and lower temperatures in creep and recovery experiments on conventional and modified asphalt binDe.S for both shear and tensile creep.

Cite this publication as follows:
Hampl R, Vacin O, Jasso M, Stastna J, Zanzotto L: Modeling of tensile creep and recovery of polymer modified asphalt binders at low temperatures, Appl. Rheol. 25 (2015) 34675.

Paulo R. De.Souza Mendes, Alexandra A. Alicke, Roney L. Thompson
Parallel-plate geometry correction for transient rheometric experiments

Appl. Rheol. 24:5 (2014) 52721 (10 pages)

It is well known that the shear and shear rate are not uniform in the azimuthal flow within the gap between parallel concentric disks - perhaps the most versatile among the geometries used in rheometry. This flow inhomogeneity represents a disadvantage, because the data analysis becomes intricate. Typically the stress is calculated at the rim with the assumption that it varies linearly with the radial coordinate, and then a correction is applied. This correction may be very large, depending on the nature of the sample, type of test, and range of parameters. While for steady-state shear flow different methods for correcting the stress are available, for transient flows they are rather scarce and in some cases unavailable. In this work we analyze in detail the stress correction for the main rheometric experiments, and discuss when it is needed. To this end, we performed different tests with a commercial hair gel and a polyacrylamiDe.Solution. For oscillatory flows, a simple equation to correct the stress amplitude is obtained in terms of the amplitudes of the torque and shear rate.

Cite this publication as follows:
deSouzaMendes PR, Alicke AA, Thompson RL: Parallel-plate geometry correction for transient rheometric experiments, Appl. Rheol. 24 (2014) 52721.

David Cheneler
Mathematical Modelling in Chemical Engineering (A. Rasmuson, B. AnDe.Sson, L. Olsson, R. AnDe.Sson)

Appl. Rheol. 24:4 (2014) 9-9

Cite this publication as follows:
Cheneler D: Mathematical Modelling in Chemical Engineering (A. Rasmuson, B. Andersson, L. Olsson, R. Andersson), Appl. Rheol. 24 (2014) 9.

Magdalena Orczykowska, Marek Dziubinski
Comparison of viscoelastic properties of chestnut and acorn starch by means of mechanical moDe.S with an in-built springpot

Appl. Rheol. 24:2 (2014) 24766 (7 pages)

The effect of concentration on viscoelastic properties of chestnut and acorn starch is discussed in the paper. The starch structure was assessed using a rheological fractional standard linear solid model FSLSM in contrary to very simple power-law model usually used in many published papers concerning determination of rheological properties of starch. Rheological parameters of this model were determined and their changes for different concentrations of the two tested types of starch were discussed. The values of the rheological parameter of FSLSM model give a useful of information concerning the elastic properties of materials such as total elasticity of networks, network oscillations, gel stiffness, structure of cross-linking and relaxation time of the materials. The proposed method for the interpretation of rheological measurements of the two types of starch allows for a comprehensive estimation of the analyzed biomaterial structure. The fractional rheological moDe.S can be very useful to control the biomaterial structure the needs of the final to meet envisaged product which is particularly significant from the point of view of materials engineering.

Cite this publication as follows:
Orczykowska M, Dziubinski M: Comparison of viscoelastic properties of chestnut and acorn starch by means of mechanical models with an in-built springpot, Appl. Rheol. 24 (2014) 24766.

Peter Fischer
UnDe.Standing Viscoelasticity - An Introduction to Rheology (Nhan Phan-Thien)

Appl. Rheol. 23:6 (2013) 329-329

Cite this publication as follows:
Fischer P: Understanding Viscoelasticity - An Introduction to Rheology (Nhan Phan-Thien), Appl. Rheol. 23 (2013) 329.

Patrick D. AnDe.Son, Peter Van Puyvelde
8th Annual European Rheology Conference (ERC 2013)

Appl. Rheol. 23:4 (2013) 235-236

Cite this publication as follows:
Anderson PD, VanPuyvelde P: 8th Annual European Rheology Conference (ERC 2013), Appl. Rheol. 23 (2013) 235.

Hai Dang Le, Geert De.Schutter, El-Hadj Kadri, Salima Aggoun, Jan Vierendeels, Serge Tichko, Peter Troch
Computational fluid dynamics calibration of Tattersall MK-II type rheometer for concrete

Appl. Rheol. 23:3 (2013) 34741 (12 pages)

Currently more and more researches have been performing concerning the numerical simulation of the behavior of fresh concrete during pumping or formwork filling. Adequate implementation of the rheology properties of fresh concrete is a determinant key to obtain realistic simulations. However, in many cases, the rheological parameters of the fresh concrete as determined by rheometers are not sufficiently accurate. The common principle of all the rheometers is not to measure directly the rheological parameters of concrete but to measure some basic physical parameters (torque, velocity, pressure, ...) that that in some cases allow the calculation of the rheological parameter in terms of fundamental physical quantities. Errors can be caused by undesired flow phenomena which are not taken into the prediction formulas and by the inaccurate prediction formulas themselves. This is directly related to the poor calibration of the rheometer that cannot cover all ranges of materials. This paper investigates the calibration of the Tattersall MK-II rheometer by performing the numerical simulation for a tremendous range of concrete flowing in the rheometer, using computational fluid dynamics (CFD). This allows to quickly and accurately obtain the rheological properties of fresh concrete, which can then be used consistently for further flow simulations. This method can be applied for all types of rheometer.

Cite this publication as follows:
Le HD, DeSchutter G, Kadri E, Aggoun S, Vierendeels J, Tichko S, Troch P: Computational fluid dynamics calibration of Tattersall MK-II type rheometer for concrete, Appl. Rheol. 23 (2013) 34741.

Selvin P. Thomas, S.K. De, I.A. Hussein
Impact of Aspect ratio of Carbon Nanotubes on shear and extensional Rheology of Polyethylene Nanocomposites

Appl. Rheol. 23:2 (2013) 23635 (10 pages)

This paper reports the results of studies on the effect of aspect ratio of multiwall carbon nanotubes (CNT) on the shear and extensional rheological behavior of low De.Sity polyethylene (LDPE) nanocomposites. Up to a CNT loading of 2 wt%, as used in the present study, the shear rheological data suggest no network formation in the nanocomposites, irrespective of the aspect ratio of the nano filler. Dynamic shear viscosity η' increases with increase in loading and aspect ratio of CNT. However, at low CNT loadings (0.1 wt%) and with CNT of high aspect ratio, h. for the nanocomposites is found to be lower than that of neat polymer. Steady shear rheology results show negative values for the normal stress for the high aspect ratio CNT which is believed to be due to the tumbling of CNT with high aspect ratio. Results of extensional viscosity measurements show that extent of strain hardening is dependent on the CNT aspect ratio and follows the order, high aspect ratio > medium aspect ratio > short aspect ratio, while the time of break follows the reverse order. The effect of aspect ratio on critical extensional stress becomes prominent only at the high aspect ratio, but the stress increases with the increase in CNT loading, irrespective of the aspect ratio.

Cite this publication as follows:
Thomas SP, De S, Hussein I: Impact of Aspect ratio of Carbon Nanotubes on shear and extensional Rheology of Polyethylene Nanocomposites, Appl. Rheol. 23 (2013) 23635.

Valerie J. AnDe.Son, Gerald H. Meeten
Interpretation of T-bar tool measurements for yield stress materials

Appl. Rheol. 22:5 (2012) 55370 (9 pages)

The T-bar rheometrical tool (Brookfield Engineering Laboratories, Inc.) is a slender rod which is placed in a material and rotated horizontally about its short axis by a vertical shaft. The torque on the shaft from laminar flow of material around the rod is determined by the material.s rheological properties. T-bar experiments for a Newtonian liquid are shown to agree closely with existing theory. For yield stress materials an approximation is derived for the torque on a rotating T-bar which is supported by experiments on a range of materials. The torque for very slow rotational speed is insensitive to boundaries beyond a few T-bar diameters and is shown to correlate with the material.s yield stress and other non-Newtonian parameters. A stepdecrease in torque for each half-revolution of the T-bar was shown by some materials and possible origins of this effect are discussed.

Cite this publication as follows:
Anderson VJ, Meeten GH: Interpretation of T-bar tool measurements for yield stress materials, Appl. Rheol. 22 (2012) 55370.

Jinjun Zhang, Liping Guo, Houxing Teng
Evaluation of thixotropic moDe.S for waxy crude oils based on shear stress decay at constant shear rates

Appl. Rheol. 20:5 (2010) 53944 (7 pages)

Thixotropy is an important rheological behavior of waxy crude oils. The objective of this paper is to demonstrate existing model's abilities to describe shear stress decay behaviors of waxy crude oils at constant shear rates. Seven moDe.S specially developed for or currently used to waxy crude oils are reviewed as well as two viscoelastic-thixotropic moDe.S for human blood. Stress decay behaviors were measured for four waxy crude oils and at various temperatures. Each of the moDe.S was used to fit the stress decay plots at a single shear rate, and at multiple shear rates, respectively. Globally, Zhao's model, a complex viscoplatic model with two structure parameters and twelve physical & fitting parameters,matched the experimental plots better than other compared moDe.S. While the three moDe.S with viscoelastic backgrounds were not quite successful. For use of moDe.S, one may make choice by comprehensively considering a model's complexity in mathematic form and abilities to describe the rheological behaviors.

Cite this publication as follows:
Zhang J, Guo L, Teng H: Evaluation of thixotropic models for waxy crude oils based on shear stress decay at constant shear rates, Appl. Rheol. 20 (2010) 53944.

Benhamou Mabrouk
2nd International Workshop on Soft ConDe.Sed Matter Physics and Biological Systems (SMPPMM 2010)

Appl. Rheol. 20:3 (2010) 176-176

Cite this publication as follows:
Mabrouk B: 2nd International Workshop on Soft Condensed Matter Physics and Biological Systems (SMPPMM 2010), Appl. Rheol. 20 (2010) 176.

Susana Filipe, Alfons Becker, Vitor C. Barroso, Manfred Wilhelm
Evaluation of melt flow instabilities of high-De.Sity polyethylenes via an optimised method for detection and analysis of the pressure fluctuations in capillary rheometry

Appl. Rheol. 19:2 (2009) 23345 (12 pages)

An optimised method for the detection and analysis of the time dependent pressure associated with the development of melt flow instabilities during extrusion through a capillary die was developed and validated. The magnitude and frequency of the developed quasi-periodic distortions, as well as the pressure profiles along the die length, were found to depend on the MWD, topology, melt elasticity and uniaxial extensional flow properties. Both the onset and magnitude of strain hardening in uniaxial extension appear to be related to the onset for the development of melt flow instabilities under capillary flow. For a better unDe.Standing of the role of the extensional properties (namely that of a purely elastic instability) the Hencky strain to failure was also determined and correlated to the observed flow instabilities. Time resolution of the capillary rheometer was improved by a factor of 1000, pressure resolution by a factor of 100 compared to the original set-up.

Cite this publication as follows:
Filipe S, Becker A, Barroso VC, Wilhelm M: Evaluation of melt flow instabilities of high-density polyethylenes via an optimised method for detection and analysis of the pressure fluctuations in capillary rheometry, Appl. Rheol. 19 (2009) 23345.

Leslie Y. Yeo, Ravi Prakash-JagaDe.Shan, James R. Friend
Complex Fluids and Microfluidics Workshop 2008 (CFMW08)

Appl. Rheol. 19:1 (2009) 44-46

Cite this publication as follows:
Yeo LY, Prakash-Jagadeeshan R, Friend JR: Complex Fluids and Microfluidics Workshop 2008 (CFMW08), Appl. Rheol. 19 (2009) 44.

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.

Dimitri Feys, Ronny Verhoeven, Geert De.Schutter
Evaluation of time independent rheological moDe.S applicable to fresh Self-Compacting Concrete

Appl. Rheol. 17:5 (2007) 56244 (10 pages)

Self-Compacting Concrete is a new type of concrete which is more liquid compared to traditional concrete and which does not need any form of external compaction. As a result this type of concrete is suitable for a new placing technique: pumping SCC from the bottom in the formwork and letting it rise in the formwork due to the applied pressure. In order to unDe.Stand the phenomena occurring during pumping operations, the rheological properties of SCC must be investigated and controlled. Tests have been performed with two different rheometers, which are described in this paper. For the Tattersall Mk-II rheometer, a calibration procedure has been worked out to eliminate secondary flows in the rheometer.Test results indicate that SCC is a thixotropic liquid, having a yield stress, showing shear thickening and having varying properties in time due to the occurring chemical reactions. In this paper, the time dependent effects will not be described. When trying to apply a rheological model to the obtained results, only the modified Bingham model seems appropriate. Applying the Bingham model results in the generation of negative yield stresses while the Herschel-Bulkley model has a parameter with a variable dimension and has a major mathematical restriction. The rheological properties of fresh SCC can be described with the modified Bingham model. A suitable parameter to describe shear thickening is defined as the ratio of the second order term in the shear rate of the modified Bingham model to the linear term (= c/μ).

Cite this publication as follows:
Feys D, Verhoeven R, DeSchutter G: Evaluation of time independent rheological models applicable to fresh Self-Compacting Concrete, Appl. Rheol. 17 (2007) 56244.

B. Mokdad, E. Pruliere, A. Ammar, F. Chinesta
On the simulation of kinetic theory moDe.S of complex fluids using the Fokker-Planck approach

Appl. Rheol. 17:2 (2007) 26494 (14 pages)

MoDe.S of kinetic theory provide a coarse-grained description of molecular configurations wherein atomistic processes are ignored. The Fokker-Planck equation related to the kinetic theory descriptions must be solved for the distribution function in both physical and configuration spaces. When the model involves high dimensional spaces (including physical and conformation spaces and time) standard discretization techniques fail due to excessive computation requirements. In this paper, we revisit some model reduction techniques recently proposed to circumvent those difficulties, exploring other new application areas related to entangled polymer moDe.S as well as the use of such reduced moDe.S for treating complex flows in which the distribution function involves both the physical and the conformation coordinates.

Cite this publication as follows:
Mokdad B, Pruliere, re E, Ammar A, Chinesta F: On the simulation of kinetic theory models of complex fluids using the Fokker-Planck approach, Appl. Rheol. 17 (2007) 26494.

Frank de Hoog, Robert AnDe.Ssen
Simple and Accurate Formulas for Flow-Curve Recovery from Couette Rheometer Data

Appl. Rheol. 16:6 (2006) 321-328

In Couette rheometry, most of the current flow-curve recovery algorithms require the explicit numerical differentiation of the measured angular velocity data. The exceptions and popular choices, because it avoids the need for a numerical differentiation, are the parallel plate approximation (cf. Bird et al. [1], Table 10.2-1) and the simplest of the formulas given in Krieger and Elrod [2]. However, their applicability is limited to narrow gap rheometer data. In this paper, equally simple formulas are presented which are exact for Newtonian fluids, do not involve a numerical differentiation and are consistently more accurate than the simple formulas mentioned above. They are based on a generalization of the Euler-Maclaurin sum formula solution of the Couette viscometry equation given in Krieger and Elrod. As well as illustrating the improved accuracy for the recovery of flow-curves for fluids with and without a yield-stress, details about more general and accurate formulas for flow-curve recovery from Couette rheometry data are given. The situation for the recovery of flow-curves from wide gap rheometery measurements is also discussed.

Cite this publication as follows:
deHoog F, Anderssen R: Simple and Accurate Formulas for Flow-Curve Recovery from Couette Rheometer Data, Appl. Rheol. 16 (2006) 321.

Patrick D. AnDe.Son, Joseph Dooley, Han E.H. Meijer
Viscoelastic effects in multilayer polymer extrusion

Appl. Rheol. 16:4 (2006) 198-205

The effect of viscoelasticity on multilayer polymer extrusion is discussed. In these coextrusion processes predetermined patterns are created with a remarkable breadth of complexity even in geometrically simple dies via elastic rearrangements caused by the second-normal stress differences. A computational method is offered, based on the mapping method, which quantitatively describes the flow-induced patterns. Besides that the results are esthetically beautiful, they are also relevant for practice, since process and die design optimization is now possible. Not only to minimize interface distortion, but potentially also to deliberately create new processes and products based on this flow-induced patterning of polymers.

Cite this publication as follows:
Anderson PD, Dooley J, Meijer HEH: Viscoelastic effects in multilayer polymer extrusion, Appl. Rheol. 16 (2006) 198.

Patrick Ilg
MoDe.S for polymeric and anisotropic liquids (M. Kröger)

Appl. Rheol. 16:1 (2006) 12-13

Cite this publication as follows:
Ilg P: Models for polymeric and anisotropic liquids (M. Kröger), Appl. Rheol. 16 (2006) 12.

Martin Kroger
UnDe.Standing the Properties of Matter (Michael Podesta)

Appl. Rheol. 15:5 (2005) 311-312

Cite this publication as follows:
Kroger M: Understanding the Properties of Matter (Michael Podesta), Appl. Rheol. 15 (2005) 311.

Nicolas Roussel, Christophe Lanos
Particle Fluid Separation in Shear Flow of De.Se Suspensions: Experimental Measurements on Squeezed Clay Pastes

Appl. Rheol. 14:5 (2004) 256-265

Particle fluid separation is studied in the case of slow squeezing flow of De.Se clay suspensions. The fluid pressure gradient generated by the test induces heterogeneity in the sample. Experimental water content measurements at different time points through the test allow the quantification of this separation phenomenon. The problem equations are written in the case of purely extensional flow. Based on Terzaghi principle, Darcy.s law and a Cam Clay type constitutive equation, the influence of the permeability function on the predicted void ratio evolution is studied. It is then shown that a certain water amount is strongly linked to the grains and cannot be extracted from the sample using simple compression. This critical water amount is then taken in account in the permeability function in order to predict the compression load through the test.

Cite this publication as follows:
Roussel N, Lanos C: Particle Fluid Separation in Shear Flow of Dense Suspensions: Experimental Measurements on Squeezed Clay Pastes, Appl. Rheol. 14 (2004) 256.

Walter Richtering
ConDe.Sed Matter Physics (Gert Strobl)

Appl. Rheol. 14:2 (2004) 81

Cite this publication as follows:
Richtering W: Condensed Matter Physics (Gert Strobl), Appl. Rheol. 14 (2004) 81.

Christian Friedrich
UnDe.Standing Viscoelasticity (N. Phan-Thien)

Appl. Rheol. 13:5 (2003) 240-241

Cite this publication as follows:
Friedrich C: Understanding Viscoelasticity (N. Phan-Thien), Appl. Rheol. 13 (2003) 240.

Waheed Uddin
Viscoelastic Characterization of Polymer-Modified Asphalt BinDe.S of Pavement Applications

Appl. Rheol. 13:4 (2003) 191-199

Rutting is a primary reason of premature deterioration of asphalt highway pavements. Pavements constructed with polymer and other modifiers are showing improved performance. The virgin asphalt and modified asphalt binDe.S and mixes used on several test sections of the I-55 highway rehabilitation project in northern Mississippi are compared. The laboratory creep compliance data for these binDe.S were measured at low temperatures using a modified test procedure adapted for the Bending Beam Rheometer device. Dynamic Shear Rheometer was used at high service temperatures. The creep compliance data of the binder was used as an input to simulate creep compliance behavior of the mix using a micromechanical model. The field evaluation confirms the relatively poor performance of the virgin asphalt section with respect to rutting, compared to modified binder sections.

Cite this publication as follows:
Uddin W: Viscoelastic Characterization of Polymer-Modified Asphalt Binders of Pavement Applications, Appl. Rheol. 13 (2003) 191.

Walter Richtering
UnDe.Standing rheology (F.A. Morrison)

Appl. Rheol. 12:5 (2002) 233

Cite this publication as follows:
Richtering W: Understanding rheology (F.A. Morrison), Appl. Rheol. 12 (2002) 233.

M. Lewandowski, M. Rochery, S. Bellayer,S. Fourdrin
Rheology of the Curing Process of Acrylic Latexes Used as Chemical BinDe.S

Appl. Rheol. 12:4 (2002) 174-181

The structural development undergoing during the cure of a latex polymer is accompanied by viscoelastic changes, so that this process can be investigated using a rheological approach. We present in this paper the results of a study carried out on one of the most widely used chemical binDe.S in the field of textile nonwovens: acrylic latexes. The rheological measurements have been performed on the latex films in a rectangular torsion and dynamic oscillatory mode, and the observations are discussed in terms of crosslinking. The results obtained show that the zone where crosslinking occurs in the polymer can be clearly identified by the investigation method used.

Cite this publication as follows:
Lewandowski M, Rochery M, Bellayer S, Fourdrin S: Rheology of the Curing Process of Acrylic Latexes Used as Chemical Binders, Appl. Rheol. 12 (2002) 174.

J. Marn, M. Delic, Z. Zunic
Non-Newtonian Fluid Flow Analysis with Finite Difference and Finite Volume Numerical MoDe.S

Appl. Rheol. 11:6 (2001) 325-335

Suitability of finite difference method and finite volume method for computation of incompressible non newtonian flow is analyzed. In addition, accuracy of numerical results depending of mesh size is assessed. Both methods are tested for driven cavity and compared to each other, to results from available literature and to results obtained using commercial code CFX 4.3.

Cite this publication as follows:
Marn J, Delic M, Zunic Z: Non-Newtonian Fluid Flow Analysis with Finite Difference and Finite Volume Numerical Models, Appl. Rheol. 11 (2001) 325.

Bob AnDe.Ssen
Inverse problems and emerging techniques in materials characterization

Appl. Rheol. 10:4 (2000) 194-195

Cite this publication as follows:
Anderssen B: Inverse problems and emerging techniques in materials characterization, Appl. Rheol. 10 (2000) 194.

P.D. AnDe.Son, H.E.H. Meijer
Chaotic mixing analyses by distribution matrices

Appl. Rheol. 10:3 (2000) 119-133

Distributive fluid mixing in laminar flows is studied using the concept of concentration distribution mapping matrices, which is based on the original iDe.S of Spencer & Wiley [1], describing the evolution of the composition of two fluids of identical viscosity with no interfacial tension. The flow domain is divided into cells, and large-scale variations in composition are tracked by following the cell-average concentrations of one fluid using the mapping method of Kruijt et al. [2]. An overview of recent results is presented here where prototype two- and three-dimensional timeperiodic mixing flows are considered. Efficiency of different mixing protocols are compared and for a particular example the (possible) influence of fluid rheology on mixing is studied. Moreover, an extension of the current method including the microstructure of the mixture is illustrated. Although here the method is illustrated making use of these simple flows, more practical, industrial mixers like twin screw extruDe.S can be studied using the same approach.

Cite this publication as follows:
Anderson PD, Meijer HEH: Chaotic mixing analyses by distribution matrices, Appl. Rheol. 10 (2000) 119.

Judith Weigand
Viscosity Measurements on PowDe.S with a new Viscometer

Appl. Rheol. 9:5 (1999) 204-211

Cite this publication as follows:
Weigand J: Viscosity Measurements on Powders with a new Viscometer, Appl. Rheol. 9 (1999) 204.

J. Vermant, A.B.D. Brown, M. Kroger
Time resolved evolution of soft conDe.Sed matter under flow

Appl. Rheol. 9:1 (1999) 38-39

Cite this publication as follows:
Vermant J, Brown ADB, Kroger M: Time resolved evolution of soft condensed matter under flow, Appl. Rheol. 9 (1999) 38.

R Dongré, J Youtchef, D AnDe.Son
Better Roads Through Rheology

Appl. Rheol. 6:2 (1996) 75

Cite this publication as follows:
Dongré, R, Youtchef J, Anderson D: Better Roads Through Rheology, Appl. Rheol. 6 (1996) 75.

M. Kroger
The rheology of tensiDe.Systems

Appl. Rheol. 6:2 (1996) 83-85

Cite this publication as follows:
Kroger M: The rheology of tenside systems, Appl. Rheol. 6 (1996) 83.

KD Klie
ExtruDe.S Compared

Appl. Rheol. 2:3 (1992) 187

Cite this publication as follows:
Klie KD: Extruders Compared, Appl. Rheol. 2 (1992) 187.

J Schurz
Empirical Flow Curve Interpretation of Polyethylene OxiDe.Solutions

Appl. Rheol. 2:3 (1992) 166

Cite this publication as follows:
Schurz J: Empirical Flow Curve Interpretation of Polyethylene Oxide Solutions, Appl. Rheol. 2 (1992) 166.

KD Klie
ExtruDe.S Compared

Appl. Rheol. 2:2 (1992) 118

Cite this publication as follows:
Klie KD: Extruders Compared, Appl. Rheol. 2 (1992) 118.

HJ Adler
Rheological Investigations into Water-Thinnable Paints BinDe.S

Appl. Rheol. 2:2 (1992) 96

Cite this publication as follows:
Adler HJ: Rheological Investigations into Water-Thinnable Paints Binders, Appl. Rheol. 2 (1992) 96.


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