BSR Midwinter Meeting Report
News submitted by: M.R.. Mackley | Date added: 07/01/2006
BSR Midwinter Meeting.
Department of Chemical Engineering
University of Cambridge
8/9th December 2005
Over fifty delegates attended a lively meeting at Cambridge where rheology at all levels of length scales was examined and in addition, more by accident than design, there was a good blend of modelling and experimental papers. Professor Ken Walters, (Aberystwyth University) started proceedings with a interesting lecture on “The demise of Continuum Mechanics?” This was a thought provoking starter and raised questions as to whether we can expect future breakthroughs in this field of rheology. Prof David Hayes (Surrey University) then described suspension rheology as being controlled by the interparticle potential and his modelling explored the effect of different interparticle force fields. Dr Gerry Meeton then brought us into the laboratory framework with a description of his nice squeeze flow experiments on a range of household fluids. His model worked well for most of his yield stress fluids, but when gap length scale reached the 10 of micron scale, strange things happened to the observed experimental results.
Prof Sir Sam Edwards (Cambridge) treated us to one of his great lectures starting by saying “that before you do rheology you need to understand the equilibrium state”! He then went on to describe how he and others are applying statistical mechanics to the interparticle forces between granular materials. Jason Stokes (Unilever, Colworth House) then came racing back to experimental high shear rate rheology, where he too was experiencing unexpected results when rheometer gaps became small. Finally, on the first day of the meeting, Kris Coventry of the home team presented recent Cross Slot experimental results on different molecular architecture polymers including monodisperse and branched polyethylenes.
The second day started with a grand “Tom Mcleish” overview of the current state of art relating to both the linear and non linear behaviour of flexible polymers with different molecular architecture. This was followed by a double act of Salvatore Mascia and Milan Patel (Chem Eng Cambridge) who described experimental paste squeeze flow work and matched some of the data with an analytic model developed some years ago by Petrie and Pearson. Prof Russell Davies (Aberystwyth) then received the BSR Annual award and gave a lecture on Linear Viscoelasticity and how one experimental procedure was capable of obtaining both the relaxation and retardation spectra. He gave a memorable quote in the lecture “that all lectures should include at least one theorem”! This was followed by Prof Malcolm Mackley (Cambridge) where he described recent experimental results on carbon nanotube suspensions. He put forward a “belief” as to what was happening within the material and during questions it was suggested a “conjecture” would be a more appropriate term. Finally Dr Roel van Os, as the BSR recipient of the Vernon Harrison best PhD prize, gave an impressive lecture on his work of applying spectral element methods to viscoelastic flow problems. The meeting was held in a lively and positive spirit with many delegates actively engaging in discussion. Hopefully a future Midwinter meeting will be repeated at another venue in December 2006.
Malcolm Mackley 1 January 2006