bluuebunny/crossref_metadata_2025_split huggingface dataset:
Material’s Volumetric-Flow Rate (MVR) as a Unification Parameter in Asphalt Rheology and Quality Control / Quality Assurance Tool for High Temperature Performance Grading
Authors: Shenoy Aroon 
Published: May 2019

Abstract
Rheological data of unmodified and polymer-modified asphalts are conventionally obtained from dynamic mechanical characterization and expressed in terms of sets of curves showing the variation of viscoelastic properties with frequency. Using the conventional melt flow indexer, the material’s volumetric-flow rate MVR (in cm3 / 10 minutes) through a predefined die under conditions of constant temperature and stress when obtained for the same asphalts, shows a direct relationship with the dynamic data. The MVR value helps in unifying the sets of dynamic data curves of |G*|, G” and |G* |/sin δ versus frequency in the case of unmodified asphalts, polymer-modified asphalts and asphalt mastics. The unification technique has a sound theoretical basis and the unified curves have far-reaching implications. Since MVR is so simple to determine quite accurately on a relatively inexpensive, easy-to-use flow measurement device (FMD), this parameter can be generated on paving sites or at refineries, if needed, rather than in research laboratories as is the case with the fundamental rheological parameters. The MVR can then be used as an excellent indicator of the fundamental rheological parameters through the use of the unified curves. The MVR can be utilized to accurately determine the currently used high temperature performance grade specification of paving asphalt. On account of the simplicity in obtaining this specification value from the MVR, it may be routinely used for quality control / quality assurance purposes. It can also be used as a rapid product development / formulation tool.
Melt Rheology of Tin Phosphate Glasses
Authors: Adalja Sunil B. , Otaigbe Joshua U. 
Published: May 2019

Abstract
The melt rheology of a low T

g
tin phosphate glass [Pglass] has been studied with oscillatory shear flow experiments to accelerate efforts to melt process the glass with different organic polymers. The w dependence of the complex viscosity η* of the Pglass is easily predicted by a modified Rouse model with two relaxation times. The complex viscosity of the glass at different temperatures and frequencies can be superposed and described by the Arrhenius equation. At higher temperatures, the melt viscosity of the Pglass increased monotonically with time. This viscosity rise is thought to be due to sample crystallization. The Pglass was melt-mixed with two different thermoplastic polymers (low-density polyethylene and polystyrene) to produce unique hybrid materials with interesting microstructures.
Milk Fat Composition Affects Mechanical and Rheological Properties of Processed Cheese
Authors: Jaros D. , Petrag J. , Rohm H. , Ulberth F. 
Published: May 2019

Abstract
Laboratory-scale experiments were carried out to explore the influence of the composition of the fat phase on mechanical and rheological properties of processed model cheeses. Cheeses made from caseinates, emulsifying salts and a milk fat fraction liquid at 24°C, which was achieved by thermal separation, showed much lower moduli than processed model cheeses manufactured with a fat fraction solid at 30°C. Processed model cheeses made from caseinates, emulsifying salts and a hard butter with a low amount of unsaturated fatty acids were significantly higher in firmness than cheeses made with soft butter with a higher amount of unsaturated fatty acids. In experiments using mature Gruyère and emulsifying salts, processed cheeses made from summer Gruyère were less firm than processed winter Gruyère. The results indicate that fat composition strongly affects mechanical properties of processed cheese, and a model is provided to explain structural changes during deformation.
Vane Sensor System in Small Strain Oscillatroy Testing
Authors: Junus Silvara , Briggs Jenni L. 
Published: May 2019

Abstract
To overcome difficulties (slip, sample disturbance) associated with traditional sensors, a semi-empirical method was developed to allow the use of a 4-bladed vane sensor in small strain oscillatory testing. It was assumed that the vane sensor acted as a bob with an acting radius, RV, different from the actual radius of the vane (0.02005 m). To solve for RV, the complex modulus obtained using a concentric cylinder sensor from reference viscoelastic fluid, was set equal to the complex modulus equation for vane sensor. RV values were grouped into three phase shift ranges from 5° to less than 16°, from 16° to less than 60°, and from 60° to 90° and they were 0.01883, 0.01869, and 0.01850 m, respectively. These values were used in the calculation of viscoelastic properties of eight commercial food products, which resulted in complex modulus values within 15% of those obtained using a concentric cylinder sensor. Results showed that this particular vane and cup system can be used to directly measure the storage and loss moduli of viscoelastic material and phase shift within the upper frequency value of 6.28 rad/s. Above 6.28 rad/s, there is an inconsistency in phase shift angles measured using vane method. This method is ideal for testing thixotropic food systems because disturbance is minimal during sample loading, giving more accurate viscoelastic measurements.
On-Line Rheometry for Twin-Screw Extrusion (Along the Extruder) and its Applications
Authors: Maia J. M. , Carneiro O. S. , Machado A. V. , Covas J. A. 
Published: May 2019

Abstract
Due to a number of practical difficulties, both in- and on-line measurements of the rheological properties of complex systems during extrusion are usually performed at the end of the extruder, under very specific experimental conditions. This makes this type of instruments more useful for quality control than for process optimisation, since information about the influence of the geometry and/or processing conditions on the evolution of the material characteristics inside the extruder is not easily gathered. Recently, however, the authors have developed an on-line capillary rheometry system that overcomes most of the existing problems and allows small amounts of sample to be tested in very near real time, along the extruder. The present work aims at illustrating the usefulness of this concept for the study of physical compounding processes and some reactive systems. Two very different systems will be used for that purpose: a reactive extrusion process (the peroxide-induced thermal degradation of polypropylene) and the dispersive mixing involved in the preparation of thermoplastic/carbon fibre composites.
Magneto Sweep – A New Method for Characterizing the Viscoelastic Properties of Magneto-Rheological Fluids
Authors: Wollny Klaus , Läuger Jörg , Huck Siegfried 
Published: May 2019

AbstractThe viscoelastic properties of a magneto-rheological fluid can be variably controlled using a magnetic field. A new measuring method is introduced which is based on oscillatory tests. In contrast to flow curves from experiments at steady shear rate, the new method allows an exact determination of a magneto-rheological fluid’s viscoelastic properties as a function of the preset magnetic field strength. The “Magneto Sweep” is an oscillatory test method, each with constant amplitude and constant frequency while logarithmically increasing the magnetic field strength (Magneto Sweep). For typical magneto-rheological fluids (MRF) three characteristic regions and two significant transition points can be determined. These transitions mark the corresponding change in material behavior resulting from an increasing magnetic field strength.
On numerical Simulations of Polymer Extrusion Instabilities
Authors: Achilleos Evdokia , Georgiou Georgios C. , Hatzikiriakos Savvas G. 
Published: May 2019

Abstract
The objective of this study is mainly to review recent work concerning the numerical modeling of the stick-slip and gross melt fracture polymer extrusion instabilities. Three different mechanisms of instability are discussed: (a) combination of nonlinear slip with compressibility; (b) combination of nonlinear slip with elasticity; and (c) constitutive instabilities. Furthermore, preliminary numerical simulations of the time-dependent, compressible extrudate-swell flow of a Carreau fluid with slip at the wall, using a realistic macroscopic slip equation that is based on experimental data for a high-density polyethylene, are presented.
Evaluation of a helical ribbon impeller as a viscosity measuring device for fluid foods with particles
Authors: Eriksson I. , Bolmstedt U. , Axelsson A. 
Published: May 2019

Abstract
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.
Flow Patterns of Polymer Solutions Injected into Dispersions of Bentonite
Authors: Beckmann Sabine , Niemeyer Jürgen 
Published: May 2019

Abstract
The flow behaviour of colloidal dispersions is largely influenced by the interactions between the dispersed particles. We studied the influence of either natural or synthetic polyelectrolytes solutions on flow patterns within colloidal clay dispersion. For this purpose, highly diluted aqueous polymer solutions were intruded into a radial Hele-Shaw cell filled with montmorillonite dispersions. The developing flow patterns were recorded with a high resolution digital camera. The morphological parameters: fractal dimension, total number of branching, branching density of the patterns, compactness and form were obtained by digital image analysis. The results show that the patterns are largely affected by the different polymers.
Numerical Simulation of Sharkskin Phenomena in Polymer Melts
Authors: Nithi-Uthai Nattapong , Manas-Zloczower Ica 
Published: May 2019

AbstractA fluid dynamic analysis package, PolyFlow, based on the finite element method is used to study the sharkskin phenomenon. A stick-slip mechanism is used as the basis for the simulations. This study is aimed at illustrating how fluctuations in the stress at the exit from the die cause similar fluctuations in the extrudate swell ratio, resembling the sharkskin phenomenon. Such fluctuations in the stress at the exit from the die are produced by implementing a stick-slip boundary condition at the die wall, mimicking a mechanism of molecular entanglement/disentanglement at the wall. We use a superposition of stress relaxation/stress growth and a periodic change in extrudate swell governed by the die exit stress level to depict sharkskin. Three relatively monodisperse polybutadienes were used in this study. The simulated sharkskin time period was found to be in good agreement with experimental findings. We found that the simulated pictures of sharkskin are similar for all three molecular weight samples. A comparison between the simulated sharkskin and experimental results show qualitative resemblance. The main problems preventing us from generating more quantitative sharkskin results mainly reside in the model limitations in depicting stress singularity, limitations in mesh design refinement and the constitutive model employed. In spite of these limitations, the qualitative agreement between simulation results and experimental data is good.
The Influence of Thickener Addition on Filter Cake Formation During Dewatering of Mineral Suspensions
Authors: Jäder Jerker , Järnström Lars 
Published: May 2019

Abstract
A novel method to continuously measure the rate of build-up of an immobilised layer (apparent filter cake) was demonstrated for three mineral suspensions containing carboxymethyl cellulose and polymer latex. These suspensions were designed to be similar to those normally used as coating colours within the paper industry. The instrumentation was based on a rheometer equipped with units for controlling (and measuring) the normal forces acting on the rotating upper plate and precise measurements of the gap height in parallel–plate geometry. The bottom plate in the measurement cell was perforated and connected to vacuum, giving the driving pressure for flow through the filter. The technique should so far be taken as a qualitative, but is an attractive method for measuring filtration in thin films under controlled shear rate. The technique enables the apparent filter cake height to be calculated at any time during dewatering of the coating colours.
Plastic Fluid Flow Parameters Identification Using a Simple Squeezing Test
Authors: Roussel Nicolas , Lanos Christophe 
Published: May 2019

Abstract
In this paper after a presentation of the compression test and its classical references in the rheological literature a behaviour parameter identification method is introduced using simple compression tests on concentrated geo-suspensions with a plastic fluid behaviour. The obtained theoretical test response is validated for several materials (natural soils, Kaolin clay …). It is also compared with previous solutions obtained by other authors to show that most existing solutions miss one or more terms. Elements are also given on two types of test response perturbations: the induced heterogeneity in the case of slow tests (consolidation phenomena) and the fragmentation of the outer part of sample (granular paste breakings). Finally, compression test results for a nano silica paste are presented as a example and treated as an application of the test exploitation method.
Viscoelastic Characterization of Polymer-Modified Asphalt Binders of Pavement Applications
Authors: Uddin Waheed 
Published: May 2019

AbstractRutting 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 binders 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 binders 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.
Talc Filled Thermoplastic Composites: Melt Rheological Properties
Authors: Mederic P. , Moan M. , Klopffer M.-H. , Saint-Gerard Y. 
Published: May 2019

Abstract
The effects of composition and resulting morphology on the rheology of thermoplastics filled with different talc platelets were studied in the 0-22% range of volume fraction, Φ. The sufficiently filled polymer composites exhibit a rheological behavior which significantly differs from the pure polymers used in this work, a linear low density polyethylene, a low density polyethylene and a polyamide 12. The changes in the rheological behavior are influenced by the size, the concentration and the surface treatment of plate-like talc particles. They also depend on the chemical nature and viscous and elastic characteristics of the polymer matrix. In particular, the effect of platelet orientation on the viscoelastic properties of reinforced composites was pointed out. For sufficiently filled systems, a low frequency response indicative of a pseudo solid-like behavior is obtained only during the first frequency sweep. In fact, the low frequency storage modulus, G’, is constant. With repeated frequency sweeps, more platelets were aligned in the flow direction, thus the low frequency storage modulus gradually decreases and becomes dependent on frequency, ω. The low frequency complex viscosity η* also progressively decreases with repeated frequency sweeps. In addition, for these systems, the low shear viscosity η build up in an unbounded manner because of the existence of particle-particle interactions. There are stresses below which there is no flow indicating the existence of yield values. Steady shear elastic properties are also studied, especially in the case of systems showing an apparent yield stress.
Is the Choice of Flow Curve Fitting Equation Crucial for the Estimation of Pumping Characteristics?
Authors: Malkin A.Ya. , Masalova I. , Pavlovski D. , Slatter P. 
Published: May 2019

Abstract
The answer to this provocative question is “no”! This is demonstrated by experiment and analysis for two very different materials – a highly concentrated emulsion and an 8%v/v Kaolin clay suspension. The flow curves of both materials clearly showed a low shear Newtonian asymptote and a pseudoplastic domain. The difference in the accuracy of the fitting equations relates mainly to the low shear rate domain. While the Cross equation is adequate over the full flow curve, the power law and the Herschel-Bulkley equations are clearly inadequate for the low shear rate range. These equations as well as the direct numerical method (using the Rabinowitsch-Weissenberg integral) were used for the calculation of the laminar pipe flow transport characteristics and the results were compared with experimental pipe flow data. It was shown that in all cases the maximum error did not exceed 5%, which is quite acceptable for engineering design, indicating that the choice of the flow curve fitting equation was unimportant.
Evaluating Viscosity of Surimi Paste at Different Moisture Contents
Authors: Yoon Won B. , Gunasekaran Sundaram , Park Jae W. 
Published: May 2019

Abstract
The steady and dynamic shear viscosity of fish muscle protein paste obtained from Alaska pollock surimi at 95%, 90%, 85%, 80%, and 75% of moisture contents were measured in the temperature range of 5°C to 20°C. To estimate the steady shear viscosity at high shear rate from dynamic shear viscosity, the modified Cox-Merz rule was applied by introducing a frequency shift factor. The concentration dependence of zero-shear viscosity showed power-law dependence with an exponent of 3.5, and the universal behavior of viscosity at different protein concentrations was observed by a introducing reduced variables. The Carreau model was applied to describe the shear- thinning behavior of the surimi paste, and the model parameters estimated empirically showed moisture content dependence. The viscous flow behavior was independent of temperature (5°C to 20°C), and addition of starch decreased the flow index and viscosity of the paste, compared to the pure surimi paste.
Viscosity Function for Yield-Stress Liquids
Authors: Souza Mendes Paulo R. , Dutra Eduardo S. S. 
Published: May 2019

Abstract
A viscosity function for highly-shear-thinning or yield-stress liquids such as pastes and slurries is proposed. This function is continuous and presents a low shear-rate viscosity plateau, followed by a sharp viscosity drop at a threshold shear stress value (yield stress), and a subsequent power-law region. The equation was fitted to data for Carbopol aqueous solutions at two different concentrations, a drilling fluid, an water/oil emulsion, a commercial mayonnaise, and a paper coating formulation. The quality of the fittings was generally good.
A Comprehensive Treatise of the High Temperature Specification Parameter |G*|/(1-(1/tanδsinδ)) for Performance Grading of Asphalts
Authors: Shenoy Aroon 
Published: May 2019

Abstract
The term |G*|/(1-(1/tanδ sinδ)) has been suggested as one of the best candidates for the replacement of the Super-pave specification parameter |G*|/sinδ, which has been found to be inadequate in rating polymer-modified binders for high temperature performance grading. This refinement of the Superpave specification parameter evolved through a theoretical derivation based on fundamental concepts. It was shown to be more sensitive to the variations in the phase angle δ than the original Superpave specification parameter. It thus described the unrecovered strain in the asphalt binders more accurately, and hence related to actual field performance data. This article provides a comprehensive treatise of the parameter |G*|/(1-(1/tanδ sinδ)) giving details of its derivation, salient features that are attributed to its success, comparison with actual field performance data for validation and a one-on-one comparison with the existing parameter |G*|/sinδ. It is shown that for all available field data, the parameter |G*|/(1-(1/tanδ sinδ)) does a better job in correlating with the rutting behavior than the parameter |G*|/sinδ for unmodified as well as modified asphalts. Since it is obtained in the same manner as the parameter |G*|/sinδ through the determination of |G*| and δ from a stress-controlled or strain-controlled dynamic shear rheometer, it means that no retraining of technicians and staff is required and implementation for the use of this parameter is immediate, thereby saving enormous amount of time and money. This parameter has the further advantage of being in a form easily adaptable to modeling, and thereby directly applicable for pavement design purposes.
Characteristic Times of Microsturcture Formation in Electrorheological Fluids, Determined by Viscosity and Speckle Activity Measurements
Authors: Alanis Elvio , Romero Graciela , Martinez Carlos , Alvarez Liliana , Mechetti Magdalena 
Published: May 2019

Abstract
Viscosity measurements of a suspension of cornstarch in silicone oil, at several concentrations and subject to different electrical field strengths, were conducted. An increase in the apparent viscosity, in correlation with the field strength, which is characteristic of the so-called electrorheological fluids (ERF), was observed. For a given field intensity, the value of the viscosity increases rapidly in the first seconds after the application of the electric field, and then it increases slowly until it finally approaches a saturation value. This behaviour of the apparent viscosity has been related to the microstructure formation due to interactions between dipoles induced by the electric field. Characteristic times, related to structure formation after application of an electric field, are investigated by means of diffuse light transmission and speckle-pattern activity measurements. Two characteristic times were found that should be related to the state of aggregation of the suspended particles: orientation of the non-isotropic particles and later chain formation. These results agree reasonably with that obtained from electrorheological measurements. Microscopic observations of structure formation are also reported.