01241nas a2200205   4500008004100000022001400041245013900055210006900194260010600263300001400369490000800383520037800391653002300769653003400792653001900826653001600845100003100861700002000892856012300912       2007                        eng d  a0957-416600aNovel hybrid of clay, cellulose, and thermoplastics. I. preparation and characterization of composites of ethylene-propylene copolymer0 aNovel hybrid of clay cellulose and thermoplastics I preparation   aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcMAY  a2672-26820 v1043 a<p>{The present study is aimed to prepare hybrid materials by incorporating layered silicates and microcrystalline cellulose into thermoplastic polymer. Using ethylene-propylene (EP) copolymer as thermoplastic polymer matrix and maleated EP (MEP) copolymer as compatibilizer, three types of composites were prepared by (i) melt mixing of cellulose with thermoplastics [</p>10aabrupt contraction10aArbitrary Lagrangian Eulerian10afinite element10asimulations1 aKumar, Annamalai, Pratheep1 aSingh, Raj, Pal  uhttps://library.ncl.res.in/content/novel-hybrid-clay-cellulose-and-thermoplastics-i-preparation-and-characterization-002670nas a2200229   4500008004100000022001400041245015400055210006900209260007300278300001200351490000800363520176700371653002302138653003402161653001902195653001602214100001802230700002102248700002102269700002702290856012302317       2007                        eng d  a0377-025700aSimulation of viscoelastic flows of polymer solutions in abrupt contractions using an arbitrary lagrangian eulerian (ALE) based finite element method0 aSimulation of viscoelastic flows of polymer solutions in abrupt   aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY  a157-1690 v1433 a<p>We present a method for simulation of viscoelastic flows using an Arbitrary Lagrangian Eulerian (ALE) technique based finite element formulation. The ALE technique provides advantages of both Lagrangian and Eulerian frameworks by allowing the computational mesh to move in an arbitrary manner, independent of the material motion. In the present method, a fractional step ALE technique is employed in which the Lagrangian phase of material motion and convection arising out of mesh motion are decoupled. In the first step the relevant flow and constitutive equations are solved in Lagrangian framework. The simpler representation of polymer constitutive equations in a Lagrangian framework avoids the difficulties associated with convective terms thereby resulting in a robust numerical formulation. In the second step the mesh is moved in ALE mode and the associated convection of the stress is performed using a Godunov type scheme. This ALE technique is easy to implement and can accurately simulate the complex viscoelastic behaviour of transient polymer flow through complex geometries. In the present study, steady flows through abrupt contractions of planar and axisymmetric geometries are studied by performing transient flow simulations until steady state is achieved. The proposed method is validated with previously published numerical and experimental studies for polymer solutions obeying the Oldroyd B and Phan Thien Tanner (PTT) models. The simulated corner and lip vortex enhancement mechanism and flow behavior are in good agreement with experimentally obtained flow visualization photographs. The strength of the proposed method lies in its ability to simulate free surface flows such as swell. (C) 2007 Elsevier B.V. All rights reserved.</p>10aabrupt contraction10aArbitrary Lagrangian Eulerian10afinite element10asimulations1 aGanvir, Vivek1 aLele, Ashish, K.1 aThaokar, Rochish1 aGautham, Basavarsu, P.  uhttps://library.ncl.res.in/content/simulation-viscoelastic-flows-polymer-solutions-abrupt-contractions-using-arbitrary03175nas a2200217   4500008004100000022001400041245013300055210006900188260007300257300001000330490000800340520230200348653003402650653002602684653002902710100001802739700002102757700002102778700002702799856013102826       2009                        eng d  a0377-025700aPrediction of extrudate swell in polymer melt extrusion using an Arbitrary Lagrangian Eulerian (ALE) based finite element method0 aPrediction of extrudate swell in polymer melt extrusion using an  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJAN  a21-280 v1563 a<p>Accurate prediction of extrudate (die) swell in polymer melt extrusion is important as this helps in appropriate die design for profile extrusion applications. Extrudate swell prediction has shown significant difficulties due to two key reasons. The first is the appropriate representation of the constitutive behavior of the polymer melt. The second is regarding the simulation of the free surface, which requires special techniques in the traditionally used Eulerian framework. In this paper we propose a method for simulation of extrudate swell using an Arbitrary Lagrangian Eulerian (ALE) technique based finite element formulation. The ALE technique provides advantages of both Lagrangian and Eulerian frameworks by allowing the computational mesh to move in an arbitrary manner, independent of the material motion. In the present method, a fractional-step ALE technique is employed in which the Lagrangian phase of material motion and convection arising out of mesh motion are decoupled. In the first step, the relevant flow and constitutive equations are solved in Lagrangian framework. The simpler representation of polymer constitutive equations in a Lagrangian framework avoids the difficulties associated with convective terms thereby resulting in a robust numerical formulation besides allowing for natural evolution of the free surface with the flow. In the second step, mesh is moved in ALE mode and the associated convection of the variables due to relative motion of the mesh is performed using a Godunov type scheme. While the mesh is fixed in space in the die region, the nodal points of the mesh on the extrudate free surface are allowed to move normal to flow direction with special rules to facilitate the simulation of swell. A differential exponential Phan Thien Tanner (PTT) model is used to represent the constitutive behavior of the melt. Using this method we simulate extrudate swell in planar and axisymmetric extrusion with abrupt contraction ahead of the die exit. This geometry allows the extrudate to have significant memory for shorter die lengths and acts as a good test for swell predictions. We demonstrate that our predictions of extrudate swell match well with reported experimental and numerical simulations. (c) 2008 Elsevier BY. All rights reserved.</p>10aArbitrary Lagrangian Eulerian10aExtrudate (die) swell10aFree surface simulations1 aGanvir, Vivek1 aLele, Ashish, K.1 aThaokar, Rochish1 aGautham, Basavarsu, P.  uhttps://library.ncl.res.in/content/prediction-extrudate-swell-polymer-melt-extrusion-using-arbitrary-lagrangian-eulerian-ale-0