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Jens H. Walther, a Danish citizen, was born in Aalborg Denmark in 1966. He studied at Aalborg University (1986 - 1991) and received a Master's degree in Mechanical Engineering. He continued his graduate studies at the Danish Technical University where he received a PhD in Mechanical Engineering (1994). During 1994 to 1997 we has employed as a research scientist at the Danish Meteorological Institute in Copenhagen and as a project manager in computational fluid dynamics at the Danish Maritime Institute. In 1995 he founded a consulting company (DVM Research) to work in the field of bluff body aerodynamics. From 1997 to 2000 we was a postdoctoral fellow at the Institute of Fluid Dynamics at ETH Zurich and since 2000 a research associate at the Institute of Computational Science at ETH Zurich. From 2005 he is also associate professor at the Danish Technical University at the Department of Mechanical Engineering. His research activities are in the areas of particle methods with applications in computational nanotechnology and fluid mechanics.
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Thermophoresis Between Solids: A Molecular Dynamics Study of Gold Nanoparticles Confined and Thermally Driven Through Carbon Nanotubes
J. H. Walther (1), P. A. E. Schoen (2), S. Arciadiacono (3), and D. Poulikakos (2)
(1) Institute of Computational Science, Department of Computer Science, ETH Zurich, 8092 Zurich, Switzerland
(2) Laboratory of Thermodynamics in Emerging Technologies, Department of Mechanical Engineering, ETH Zurich, 8092 Zurich, Switzerland
(3) Combustion Fundamentals Group, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
We perform molecular dynamics simulations of gold nanoparticles confined inside a carbon nanotube subject to an axial temperature gradient. The gold nanoparticle is thermally driven through the carbon nanotube by thermophoretic forces acting between the two solid materials, and in the direction opposite the thermal gradient. For single walled carbon nanotubes with a diameter of 2.35 nm and gold nanoparticles of length 4 nm we find terminal velocities of 24 to 101 ms-1 for thermal gradients ranging from 2.4 to 24 K nm-1 respectively. Using steered molecular dynamics simulations we quantify the magnitude of the thermophoretic force which is found to be proportional to the normalized thermal gradient (K.deltaT/T), and with a constant of proportionality (K) of ca. 3 kJmol-1nm-2 (0.5N/m).
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