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Flow characteristic during injection molding of PC/MWNT nanocomposites Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-11-26 Jai-Won Suh, Yeong-Eun Yoo, Sun Kyoung Kim
This work investigates the flow characteristic during injection molding process of PC/MWNT nanocomposites especially focusing on jetting. The initial flow pattern while filling has been compared with that of neat and other particle-filled PCs. The experimental results show that the flow of PC/MWNT 5% is comparable to that of PC/GF 15% and PC/CF 10%. It has been found that small amount of filled MWNT
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Controlling the emulsion stability of cosmetics through shear mixing process Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-11-26 Kwang-Mo Kim, Hee Muk Oh, Jun Hyup Lee
The manipulation of emulsion stability for kinetically sustainable cosmetic emulsions is an important technology in cosmetic industry, however the relationship between emulsifying process and long-term emulsion stability has not been elucidated. Herein, the effect of shear mixing process on the stability of oil-in-water cosmetic emulsions is investigated by varying the shear mixing rate, emulsification
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Rheological estimation of aggregate size for a colloidal suspension of carbon black particles Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-11-26 Dokyung Kim, Sangkyun Koo
Colloidal aggregation is quantitatively characterized by a rheological analysis of the colloidal suspension at various particle concentrations. The rheological analysis is combined with fractal concept to estimate the compactness, size, and size variation with shear stress on colloidal aggregates. The rheological measurement is carried out for a colloidal suspension of 24 nm carbon black particles
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Flow and mixing characteristics of a groove-embedded partitioned pipe mixer Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-11-26 Hae In Jung, Jo Eun Park, Seon Yeop Jung, Tae Gon Kang, Kyung Hyun Ahn
We propose a groove-embedded partitioned pipe mixer (GPPM) and conduct an in-depth numerical study on the flow and mixing characteristics of the GPPM in the creeping flow regime. The GPPM is a variant of a previously reported mixer, the barrier-embedded partitioned pipe mixer (BPPM), and is designed to achieve better energy-efficient mixing compared to the BPPM. In this paper, we first introduce the
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Study of EDL phenomenon in Peristaltic pumping of a Phan-Thien-Tanner Fluid through asymmetric channel Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-11-26 J. Prakash, Dharmendra Tripathi
This paper is mainly attained to examine the electric double layer (EDL) phenomena and rheological effects on peristaltic pumping through asymmetric microchannel in presence of Lorentz force. To examine the electroosmosis mechanism, Poisson-Boltzmann equation is considered. To describe the rheological behavior of the fluids, a Phan-Thien-Tanner model is taken into account. The governing equations are
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Shear viscosity calculation of water in nanochannel: molecular dynamics simulation Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-11-26 Alireza Shadloo-Jahromi, Masoud Kharati-Koopaee, Rasoul Khaledialidusti
Shear viscosity is one of the important transport properties which affects different phenomena in nanoconfined water. This study aims to investigate the effect of sub-Angstrom variations of nanochannel size on the shear viscosity of water confined in a silicon wall by employing equilibrium molecular dynamics (EMD) simulations. Simulation results demonstrate that water molecules confined in the slits
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Supercritical bifurcation to periodic melt fracture as the 1 st transition to 2D elastic flow instability Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-11-26 Youngdon Kwon
This study, employing a numerical approximation, computationally describes 2D melt fracture as elastic instability in the flow along and outside a straight channel. In the preceding research (Kwon, 2018, Numerical modeling of two-dimensional melt fracture instability in viscoelastic flow, J. Fluid Mech. 855, 595–615) several types of unique instability and corresponding bifurcations such as subcritical
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Mathematical model on magneto-hydrodynamic dispersion in a porous medium under the influence of bulk chemical reaction Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-11-26 Ashis Kumar Roy, Apu Kumar Saha, R. Ponalagusamy, Sudip Debnath
The mathematical model of hydrodynamic dispersion through a porous medium is developed in the presence of transversely applied magnetic fields and axial harmonic pressure gradient. The solute introduce into the flow is experienced a first-order chemical reaction with flowing liquid. The dispersion coefficient is numerically determined using Aris’s moment equation of solute concentration. The numerical
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Performance of OMMT/SBS on the rheological properties of asphalt binder Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-11-26 Peerzada Mosir Shah, Mohammad Shafi Mir
Nanoclays have been successfully introduced into the asphalt binder, either separately or into the polymer modified asphalt binder resulting in the improved mechanical and rheological properties of the asphalt binder. The present research study was undertaken to evaluate the influence of organically modified montmorillonite clay (OMMT) in pure asphalt binder and also in styrene butadiene styrene (SBS)
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A study on the boundary of linear viscoelasticity in simple shear flows: model calculations Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-08-27 Taehoon Kim; Junghaeng Lee; Kwang Soo Cho; Hye-Jin Ahn; Ki-Won Song
Linear viscoelastic region is important to investigate material properties. We investigated boundary of linear viscoelasticity for simple shear flows with various time functions of shear strain. We used Phan-Thien and Tanner (PTT) model and Giesekus model in order to extract the linearity criterion. We determined critical strain (γc) as a function of dimensionless number such as De or Wi and the nonlinear
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Study on binary collision of rod-like particles under simple shear flow Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-08-27 Hyun Seop Lee; Chong Youp Kim
In this study a theoretical study is carried out on the collision of two rod-like particles suspended in Newtonian fluid under a shear flow. The length of the particle is fixed at 2 µm while the diameter is varied so that the aspect ratio (length/diameter) varies from 1 to 20. Liquid viscosity is changed from 0.01 to 1 Pa·s. The Brownian motion is considered to be negligible. Both hydrodynamic and
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Simulations for the flow of viscoplastic fluids in a cavity driven by the movement of walls by Lattice Boltzmann Method Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-08-27 Siva Subrahmanyam Mendu; Prasanta Kumar Das
The current paper is focused on analyzing the flow of viscoplastic fluid in a cavity that is driven by the two walls. The Lattice Boltzmann method (LBM) is used to solve the discrete Boltzmann equation. To represent the stress-strain rate relationship of viscoplastic fluids, the Bingham Papanastasiou constitutive model is considered. Cavity flow filled with Bingham fluids is considered for validating
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Coagulation kinetics of round-sided disk particles under simple shear flow Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-08-27 Hyun Seop Lee; Chong Youp Kim
In this study a theoretical study is carried out on the binary collision of round-sided disks (RSD) suspended in a Newtonian fluid under a simple shear flow. RSD is composed of a disk part and a half-torus part which circumscribes the side of the disk. The diameter of the disk is fixed at 2 µm while the thickness and the half-torus size are varied so that the aspect ratio varies from 0.13 to 0.288
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Generation mechanism of gloss defect for high-glossy injection-molded surface Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-08-27 Jinsu Gim; Byungohk Rhee
The gloss defect on a glossy surface is one of the surface defects to be found on injection-molded products. In this paper, the effects of the filling and packing stages on surface gloss are investigated. Based on observations, a generation mechanism of gloss difference is proposed. The difference of the surface gloss can be explained by the replication of the shrinking polymer surface represented
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Localization behavior of multiwalled carbon nanotubes in ternary blends of PC, SAN, and PMMA Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-05-27 Seok Ho Yang; Jeong Woo Lee; Hyungsu Kim
In this study, the localization behavior of multiwalled carbon nanotubes (MWCNTs) was investigated in the ternary blends based on PC/SAN/PMMA (60/30/10). The major interest was focused on the effects of two different SANs having AN contents of 24 and 32 wt.% (SAN24 and SAN32, respectively) and PMMA on the phase structure of the composites. It was found that the spreading of PMMA around SAN32 was pronounced
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A simple method of correcting the parallel plate rim shear stress for non-Newtonian behavior Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-05-27 Pengfei Liu; Yang Wang; Yee-Kwong Leong; Seung Hyuk Kwon; Hyoung Jin Choi
In the rheological characterization of non-Newtonian fluids in a steady torsional shear flow using a parallel-plate geometry, there is a need to correct the shear stress at the rim for non-Newtonian behavior. Solving the governing torsional flow equation inversely by Tikhonov regularization using experimental torque vs. rim shear rate data is the most scientific method for obtaining the model independent
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A thermal based RBC Aggregation model for two-phase blood flow Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-05-27 Erke Aribas; Mustafa Serdar Celebi
Creating a reliable and accurate Red Blood Cell (RBC) aggregation model for small and midsize arteries and veins is still an active research subject with more in focus with a multi-scale approach including mesoscale effects. Better understanding the RBC aggregation requires a multi-phase and multi-scale approach for simulating blood with Newtonian and non-Newtonian parts. In our proposed work, viscosity
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Rheological Properties and Phase Structure of Polypropylene/Polystyrene/Multiwalled Carbon Nanotube Composites Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-05-27 Jaegun Lee; Hyungsu Kim
In this work, nanocomposites of polypropylene (PP)/polystyrene (PS)/multi-walled carbon nanotube (MWCNT) were prepared by the sonochemical polymerization of styrene in the presence of PP and MWCNT. This procedure offered a composite (PP-g-PS/MWCNT) having a unique phase structure in which MWCNTs are distributed in both phases of PP and PS, which is contrary to the typical observations in the composites
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Numerical investigation of a non-Newtonian fluid squeezed between two parallel disks Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-05-27 Mehdi Shafahi; Nariman Ashrafi
The transient, axisymmetric squeeze flow of the non-Newtonian shear thinning material between finite disks is studied numerically. The fluid between disks is assumed to follow the Carreau-Bird model. Two disks approach each other at a constant velocity while no-slip boundary condition is assumed. The time dependent simulation shows the effect of fluid nonlinearity, flow parameters and geometric aspect
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Comparative numerical and experimental investigation of process viscometry for flows in an agitator with a flat blade turbine impeller Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-05-27 Hae Jin Jo; Young Ju Kim; Wook Ryol Hwang
This paper presents a method for measuring the viscosity of generalized Newtonian fluid directly in flows generated by flat-blade turbine impellers, which are commonly used for moderate mixing and dispersion. A flat-blade turbine with four blades is defined as a model system and analyzed through numerical simulations with experimental verification. Carbopol 940 solution, a high viscosity non-Newtonian
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Determination of velocity profiles of Bird-Carreau fluids in curvilinear microchannels using random sample consensus Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-05-27 Kyu Yoon; Hyun Wook Jung; Myung-Suk Chun
Flow features of rheologically complex fluids inside curved microchannels should be meaningfully scrutinized for effective mixing, sorting, and manipulation of nano- and micro-sized colloids or particles. In this study, a particle streak velocimetry method with coordinate transformation is incorporated to depict experimentally the axial velocity profiles of Newtonian and non-Newtonian (Bird-Carreau
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Hydroelastic instability of viscoelastic fluids in developing flow through a compliant channel Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-05-27 Morteza Safarifard; Zahra Aghaee; Mohammad Pourjafar; Solmaz Bazargan; Kayvan Sadeghy
Linear stability of a viscoelastic fluid obeying the Walters’ B model is analytically and numerically investigated in the entrance region of a plane channel formed between two parallel plates. The plates are compliant and obey the two degree-of-freedom von Karman solid model. Having obtained the base-flow velocity profiles using the boundary-layer theory, their vulnerability to infinitesimally small
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High temperature extensional rheology of commercially available polycarbonate mixed with flame retardant salts Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-02-24 Samrat Sur; Manojkumar Chellamuthu; Jonathan Rothstein
In this paper, we present a study of the dripping properties of polycarbonate (PC) modified with combinations of earth metal salts of inorganic sulfur, potassium perfluorobutane sulfonate (Rimar); non-halogenated flame retardant additives, potassium diphenyl sulfone-3-Sulfonate (KSS); and block co-polymers-polytetrafluoroethylene encapsulated with styrene acrylonitrile resin (T-SAN). Measurements of
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Fabrication of PBAT/polyethylene blends mulching film via blown film extrusion process Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-02-24 Jung Gu Han; Seung Joon Park
To extend the period of decomposition and property degradation of polybutylene adipate terephthalate (PBAT) mulching film for long-term use, PBAT was compounded with polyethylene mixture (LDPE: LLDPE = 15:85), calcium carbonate, and illite. PBAT mulching films were prepared using a blown film extrusion process with 80 mm diameter blowing die. To improve mechanical properties and processability of the
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Change of rheological/mechanical properties of poly(caprolactone)/CaCO 3 composite with particle surface modification Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-02-24 Ji Hwan Kim; Jung Hyun Ahn; Joung Sook Hong; Kyung Hyun Ahn
In order to investigate how particle aggregation affects tensile mechanical performance of composite, a ductile biopolymer (poly(caprolactone)) was melt-compounded with CaCO3 particles over a wide concentration range from 10 to 60 wt.%. The aggregation of CaCO3 particles in poly(caprolactone) (PCL) is investigated depending on particle concentration and surface modification (with stearic acid (2.5
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Secondary Dean flow characteristics of inelastic Bird-Carreau fluids in curved microchannels Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-02-24 Kyu Yoon; Hyun Wook Jung; Myung-Suk Chun
To effectively control the mixing of target materials inside microfluidic devices, the Dean flow features of generalized-Newtonian Bird-Carreau (BC) fluids in curved rectangular channels are theoretically investigated, as a passive technique. Governing equations coupled with the Cauchy momentum equation and the BC model are solved using the finite volume scheme with a semi-implicit method for pressure-linked
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Drag reduction characterizations of turbulent channel flow with surfactant additive by proper orthogonal decomposition and wavelet transform Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-02-24 Lu Wang; Zhiying Zheng; Weihua Cai; Fengchen Li
To explore the drag-reducing characteristics of turbulent channel flows with surfactant additive at relatively high Reynolds number from the perspectives of energy spectrum and multi-scale resolution, the two-dimensional fluctuation velocity fields of turbulent channel flows with/without surfactant additive at Reynolds number of Reτ = 590 obtained by large eddy simulation are decomposed by two-dimensional
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Mucoadhesive and pH-responsive behavior of gelatin containing hydrogels for protein drug delivery applications Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-02-24 Jihwan Oh; Bumsang Kim
Novel gelatin-containing polymer hydrogels that can be used as mucoadhesive delivery systems were developed. Poly(acrylic acid) hydrogels were modified by copolymerizing gelatin as adhesion promoter, to improve the adhesion to the mucus layer and the synthesized copolymer of acrylic acid (AA) and methacrylated gelatin (GelMA) were designated as P(AA-co-GelMA). The pH-sensitivity and the mucoadhesive
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The rheological properties and gelation kinetics of corn starch/bovine serum albumin blend Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-02-24 Osita Sunday Nnyigide; Kyu Hyun
The rheological properties and gelation kinetics of corn starch (CS)/bovine serum albumin (BSA) blends were investigated using the mass ratio of [CS]/[BSA] of 0, 0.5, 1, 2, and 3. The results from the temperature ramp and time sweep tests within linear viscoelastic regime showed a decrease in the gelation temperature (Tgel) and gelation time (tgel) of the BSA with increasing the mass ratio of [CS]/[BSA]
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Microfluidic-based effective monitoring of bloods by measuring RBC aggregation and blood viscosity under stepwise varying shear rates Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2020-02-24 Yang Jun Kang
To effectively discriminate changes in blood samples, RBCs aggregation and blood viscosity should be evaluated independently and simultaneously. In this study, by setting two syringe pumps for delivering two fluids (blood sample and reference fluid) at stepwise varying flow rates, RBCs aggregation (AI) and viscosity (µBlood) are sequentially measured by quantifying image intensity of blood flows ()
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Multi-chain slip-spring simulations for polyisoprene melts Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-11-25 Yuichi Masubuchi; Takashi Uneyama
The multi-chain slip-spring (MCSS) model is a coarse-grained molecular model developed for efficient simulations of the dynamics of entangled polymers. In this study, we examined the model for the viscoelasticity of polyisoprene (PI) melts, for which the data are available in the literature. We determined the conversion factor for the molecular weight from the fitting of the molecular weight dependence
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Nonlinear material functions under medium amplitude oscillatory shear (MAOS) flow Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-11-25 Hyeong Yong Song; Kyu Hyun
Dynamic oscillatory shear flow has been widely used to investigate viscoelastic material functions. In particular, small amplitude oscillatory shear (SAOS) tests have become the canonical method for characterizing the linear viscoelastic properties of complex fluids based on strong theoretical background and plenty of experimental results. Recently, there has been increasing interest in the use of
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Modelling contraction flows of bi-disperse polymer blends using the Rolie-Poly and Rolie-Double-Poly equations Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-11-25 Adila A. Azahar; Oliver G. Harlen; Mark A. Walkley
The flow of a bi-disperse polymer melt through a hyperbolic contraction is simulated using the recently proposed Rolie-Double-Poly constitutive model (Boudara et al., 2019). This simplified tube model takes account of the nonlinear coupling between the dynamics of the long and short-chains in a bi-disperse blend, in particular it reproduces the enhancement of the stretch relaxation time that arises
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Uniaxial extensional viscosity of semidilute DNA solutions Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-11-25 Sharadwata Pan; Duc At Nguyen; P. Sunthar; T. Sridhar; J. Ravi Prakash
The extensional rheology of polymer melts and dilute polymer solutions has been extensively examined through experiments and theoretical predictions. However, a systematic study of the extensional rheology of polymer solutions in the semidilute regime, in terms of examining the effects of concentration and molecular weight, has not been carried out so far. Previous experimental studies of the shear
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Stability of flows with the BMP model in the yield stress limit Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-11-25 Ian Frigaard; Alondra Renteria
Common features of complex fluids include yield stress, thixotropy and elasticity. A comprehensive constitutive model attempts to effectively predict flow responses dominated by such characteristics. Nevertheless, when constructing a constitutive model that deals with yield stress fluids one must try to preserve the fundamental characteristics of a yield stress. This paper explores the static and energy
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Vortex dynamics at the junction of Y-shaped microchannels in dilute polymer solutions Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-11-25 Yong-Min Park; Sun Ok Hong; Pyung Cheon Lee; Ju Min Kim
Understanding the vortex dynamics in polymer solutions is one of keys for the flow control in a wide range of polymer-related material processing applications. Vortex is generated due to the viscoelasticity of polymer solution, even if no vortex formation is expected under Newtonian flow conditions. In addition, the chaotic vortices generated in viscoelastic fluids have been recently exploited to mix
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Towards unraveling the sintering process of two polystyrene particles by numerical simulations Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-11-25 Caroline Balemans; Prakhyat Hejmady; Ruth Cardinaels; Patrick D. Anderson
In this work, we study different rheological and thermal phenomena present during laser sintering of two polystyrene (PS) particles using fully resolved numerical simulations. In our analysis, we varied the laser power, the initial temperature and the thermal convection coefficient, used different rheological descriptions for the flow behavior and in addition studied the effect of the substrate (used
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Ultrafast imaging of soft materials during shear flow Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-11-25 Gabriele Colombo; Roberta Massaro; Steven Coleman; Jörg Läuger; Peter Van Puyvelde; Jan Vermant
The direct imaging of flow induced microstructural changes in complex fluids can have advantages over the use of scattering methods, since localized phenomena can be observed directly and more mechanistic insights can be obtained. This is useful in particular for materials with hierarchical or multiscale structures such as aggregated dispersions. Rheoconfocal instruments are ideally suited for this
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Rheological characterization of BCC and FCC structures in aqueous diblock copolymer liquid crystals Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-11-25 Connor S. Valentine; Lynn M. Walker
Low molecular weight, amphiphilic diblock copolymers in selective solvent exhibit complex phase behavior and macroscopic properties that affect the processing and application of these materials. The mechanical properties of the crystalline phases seen in concentrated solutions are dependent on nanoscale structure and sample history. The goal of this study is to characterize macroscopic properties and
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What controls filament thinning in uniaxial extension? Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-11-25 Walter Oswald; Steffen M. Recktenwald; Norbert Willenbacher
Breakup of fluid threads is omnipresent in nature and highly relevant for technical processes such as atomization, printing, coating, or spinning. We discuss how to control the filament lifetime of shear-thinning, viscoelastic fluids during uniaxial extension without affecting their shear viscosity. Two commercial acrylic thickeners differing with respect to the co-polymerized hydrophobic monomers
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Scaling analysis on the linear viscoelasticity of cellulose 1-ethyl-3-methyl imidazolium acetate solutions Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-08-23 Mi Kyung Kwon; Junghaeng Lee; Kwang Soo Cho; Sung Jun Lee; Hyun Chul Kim; Sang Won Jeong; Se Geun Lee
Many researches have studied the viscoelasticity of cellulose/ionic liquid solutions through the conventional scaling rules which assume the monodisperse polymer. However, they are not suitable for cellulose since natural polymers such as cellulose have molecular weight distribution. In this paper, dynamic rheological behaviors of 1-ethyl-3-methyl imidazolium acetate solutions dissolving three kinds
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Predicting the excess pressure drop incurred by LPTT fluids in flow through a planar constricted channel Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-08-23 Taha Rezaee; Mostafa Esmaeili; Solmaz Bazargan; Kayvan Sadeghy
Laminar flow of a viscoelastic fluid obeying the linear simplified Phan-Thien/Tanner model (LPTT) is numerically studied in a planar channel partially obstructed by a cosinusoidal constriction. Based on published data (Tammadon-Jahromi et al., 2011) there is no excess pressure drop for this particular fluid when flowing through an orifice-plate. Numerical results obtained using OpenFoam software at
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Three-dimensional numerical simulation for resin transfer molding of automotive wheel Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-08-23 Zheng Min Huang; So Yun Lee; Hyung Min Kim; Jae Ryoun Youn; Young Seok Song
Resin transfer molding (RTM) is a manufacturing process that uses liquid resin to saturate a fiber preform placed in a closed mold cavity. For robust fabrication of the composite, fiber preform needs to be completely impregnated with polymer resin during mold filling. Hence, the understanding of resin flow and void formation in RTM is very important to design the mold and processing conditions for
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Effects of dispersion state on rheological and electrical characteristics of concentrated multiwalled carbon nanotube suspensions Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-08-23 Min Hwan Kim; Seung Hyuk Kwon; Hyoung Jin Choi
We report a dispersion state of concentrated multiwalled carbon nanotube (MWCNT) suspensions depending on their iterative milling process. The rheological properties of concentrated suspensions prepared with different milling times were measured using a Couette-typed rotation rheometer, and their electrical characteristics were investigated via an LCR meter. The relationships of the rheological and
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Spreading behaviors of high-viscous nanofluid droplets impact on solid surfaces Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-08-23 Hai Long Liu; Xuefeng Shen; Rui Wang; Yuanping Huo; Changfeng Li; Junfeng Wang
In this work, the impact dynamics of high-viscous nanofluid droplets onto a solid surface has been investigated experimentally by means of high-speed camera visualization technique. We dispersed various nanoparticles (multiwall carbon nanotube (MWCNT), nano-graphene, and nano-graphite powder) into high-viscous base fluid (epoxy resin) to obtain the stable and homogenous nanofluids without surfactant
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Erratum to: Pairwise interaction of drops in shear-thinning inelastic fluids Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-05-27 Sadegh Mohammadi Masiri,Morteza Bayareh,Afshin Ahmadi Nadooshan
Due to an error at the publisher, Eq. (1) for authors Sadegh Mohammadi Masiri et al . was listed incorrectly. The original Eq. (1) is as follows:
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Peristaltic transport of thixotropic fluids: A numerical simulation Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-05-27 S. M. J. Sobhani; N. P. Khabazi; S. Bazargan; P. Sadeghi; K. Sadeghy
Peristaltic flow of a thixotropic fluid obeying the Moore model is numerically studied using the multiple-relaxation-time lattice Boltzmann method (MRT-LBM). Converged results could be obtained in a planar two-dimensional channel at large Reynolds numbers for arbitrary wavelengths and amplitude ratios for nonzero Reynolds numbers. It is shown that depending on the Reynolds number and the parameters
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Rheological and electrical properties of polystyrene nanocomposites via incorporation of polymer-wrapped carbon nanotubes Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-05-27 Jae Sang Park; Ji Hun An; Keon-Soo Jang; Seong Jae Lee
Carbon nanotubes (CNTs) are used as nanofillers in polymer nanocomposites to improve the properties of a matrix polymer because of their excellent properties. However, CNTs tend to aggregate due to the strong van der Waals force between CNTs. To solve the problem, surface-modified CNTs with hydrophilic polymers, such as polyvinyl pyrrolidone (PVP) and polystyrene sulfonate (PSS), were employed. Polystyrene
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Precise and quantitative assessment of automotive coating adhesion using new microgap pull-off test Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-05-27 Chi Hyeong Cho; Intae Son; Ji Yong Yoo; Gitae Moon; Eunbi Lee; Sung Ho Yoon; Jae Sik Seo; Choon Soo Lee; Jun Hyup Lee
The quantification of coating adhesion on substrates is an important technology that has recently received much attention in automotive industry because the adhesion characteristics of automotive paints have a great influence on color and appearance of automobiles. Here, we present a robust and precise method for quantifying the coating adhesion of automotive paints on flat substrates using new microgap
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A rheological model to predict viscosity of dispersions as a function of the modified Peclet number Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-05-27 Jerzy P. Sęk; Mariola M. Błaszczyk; Łukasz Przybysz
The suspensions and emulsions are important products and raw materials for various industrial production and processing branches. The knowledge concerning the rheological properties of such substances is of key importance for many manufacturing processes. Many dependences can be found within the literature but there is lack of model that takes into account the influence of inner phase concentration
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Investigation of rheological behaviors of polyolefin blend type thermoplastic elastomers for quantifying microstructure-property relationships Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-05-27 Ali Durmus; Mine Begum Alanalp; Ismail Aydin
Polyolefin blend type thermoplastic elastomers (TPEs) were prepared via melt blending method in a twin screw extruder by using isotactic polypropylene (i-PP), three different styrene-olefin triblock copolymers (SEBS-1 and SEBS-2 having a styrene content of 30 wt.% and 60 wt.%, respectively and SEEPS having a styrene content of 30 wt.%) and paraffinic oil. Composition-dependent and time-dependent viscoelastic
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A finite-element technique for flows in the single screw extruder using a partial periodic unit Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-02-26 Kyung Hoon Lim; Wook Ryol Hwang; See Jo Kim
It is of great importance to understand and predict screw characteristics (SC) during the single screw extrusion process for the extruder design and the operation optimization. In order to simulate SC effectively, we introduce the concept of a partial rotational fraction for a partial periodic unit of helical geometry in the metering section of the single screw extruder. In this work, the partial rotational
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Magnetorheological characteristics of carbonyl iron microparticles with different shapes Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-02-26 Jae Yun Lee; Seung Hyuk Kwon; Hyoung Jin Choi
Two different shapes of spherical- and flake-like soft-magnetic carbonyl iron (CI) microparticles were dispersed in silicone oil to prepare magnetorheological (MR) fluids. The magnetic-field dependent rheological behaviors of the MR fluids were scrutinized focusing on their shape effect. Saturation magnetization of the flake-shaped CI was obtained to be slightly lower than that of spherical-shaped
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First-harmonic intrinsic nonlinearity of model polymer solutions in medium amplitude oscillatory shear (MAOS) Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-02-26 Hyeong Yong Song; Kyu Hyun
First-harmonic MAOS moduli were demonstrated experimentally using monodisperse linear polystyrene (PS) solutions at different concentrations. Two first-harmonic intrinsic nonlinearities are asymptotic deviations from two linear viscoelastic moduli and obtained in medium amplitude oscillatory shear (MAOS) regime. Master curves of first-harmonic MAOS moduli for PS solutions provided novel information
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Enhanced impact strength of injection-compression molded parts by controlling residual stress distribution Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-02-26 Hwa Jin Oh; Young Seok Song
The objective of this study is to elucidate the relation between the results of ball drop tests and the residual stress distribution of an injection-compression molded part. To improve the ball drop property, a high impact material and a robust manufacturing process were employed. For the application to the transparent plastic window, it is of great importance to increase the impact strength of plastic
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Pairwise interaction of drops in shear-thinning inelastic fluids Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-02-26 Sadegh Mohammadi Masiri; Morteza Bayareh; Afshin Ahmadi Nadooshan
Inelasticity effects on the migration of a drop and pairwise interaction of drops in a simple shear flow are studied using a finite-difference front-tracking method. The Carreau-Yasuda model is used to adjust the shear-thinning behavior of fluids. Results showed that drop deformation and migration rate of drops in an inelastic system are smaller than those in a Newtonian one. It was revealed that inelasticity
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A numerical study of the influence of operating conditions of a blade free planetary mixer on blending of cohesive powders Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-02-26 Kwon Joong Son
A blade-free planetary mixer provides an effective and rapid mixing of cohesive powders due to its powerful centrifugal agitation capability to produce a swirling flow pattern in a mixing vessel. Despite its popular use in the powder processing industry, the dynamics and characteristics of blade-free planetary mixing are still not well understood because of a lack of experimental and numerical studies
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Enhanced coalescence of two oil droplets with clay particles Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2019-02-26 Joung Sook Hong
In order to investigate the effects of clay particles on the coalescence of oil droplets, a typical head-on experiment was carried out. The coalescence of two oil drops containing clay was observed depending on the clay types. The influence of clay on the coalescence of oil droplets is successfully distinguished from the coalescence of pure oil droplets. When two oil droplets make direct contact, pure
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Effect of sulfur on the rheological properties and phase structure of polycarbonate/ poly(styrene-co-acrylonitrile)/multiwalled carbon nanotube composites Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2018-11-23 Kyungmin Chung; Hyungsu Kim
Elemental sulfur has been introduced to the suspensions of polycarbonate (PC), poly(styrene-co-acrylonitrile) (SAN) and multi-walled carbon nanotubes (MWCNT). A particular interest was focused on the effect of sulfur diradicals on the rheological properties and phase structure of the sonicated composites. The melt viscosities, elasticities, and relaxation moduli of the PC/SAN/MWCNT composites were
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Characterization of the viscoelastic model of in vivo human posterior thigh skin using ramp-relaxation indentation test Korea Aust. Rheol. J. (IF 1.39) Pub Date : 2018-11-23 Seyed Jamaleddin Mostafavi Yazdi; Kwang Soo Cho; Namcheol Kang
Characterization of viscoelastic properties of the human thigh skin can be utilized in many medical or engineering applications such as a surgical extension of the thigh skin, a tissue engineering, and a finite element modeling of thigh skin in a sitting posture. This study aims to determine the effective short- and long-term shear moduli of posterior thigh skin using ramp-relaxation test in a sitting
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