• Title/Summary/Keyword: rheology behavior

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Analysis of Grain Size Controlled Rheology Materials Dynamics for Prediction of Solid Particles Behavior (레오로지 소재의 고상입자 거동 예측을 위한 결정립 동력학 해석)

  • Kim H.I.;Kang C.G.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1337-1340
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    • 2005

  • A rheology casting technology has some advantages compared with conventional forming processes such as die casting, squeeze casting and hot/cold forming. The liquid segregation is important on mechanical properties of materials using rheology casting. In this study, so, molecular dynamics simulations were performed for the control of liquid segregation. Because the dynamics of fluid flow about nano-scaled materials is completely different from continuum, molecular dynamics simulations were used. The behavior of particles was far from the truth according to boundary conditions in simple flow. But various movement of particles appear at two or more molecular simulations.

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Shear-induced microstructure and rheology of cetylpyridinium chloride/sodium salicylate micellar solutions

  • Park, Dae-Geun;Kim, Won-Jong;Yang, Seung-Man
    • Korea-Australia Rheology Journal
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    • v.12 no.3_4
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    • pp.143-149
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    • 2000

  • In this article, we considered shear-induced microstructure and rheological behavior of micellar solutions of cationic surfactant, cetylpyridinium chloride (CPC) in the presence of a structure-forming additive, sodium salicylate (NaSal). Shear viscosity, shear moduli and flow birefringence were measured as functions of the surfactant and additive concentrations. In the presence of NaSal, the micellar solution exhibited the non-linear rheological behavior due to the formation of supramolecular structures when the molar ratio of NaSal to CPC exceeded a certain threshold value. Flow birefringence probed the change in micelle alignment under shear flow. At low shear rates, the flow birefringence increased as the shear rate increased. On the other hand, fluctuation of flow birefringence appeared from the shear rate near the onset of shear thickening, which was caused by shear-induced coagulation or aggregation. These results were confirmed by the SEM images of in situ gelified micelle structure through sol-gel route.

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