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SUMMARY:Random geometric graphs for modelling the pore system in fibre-bas
 ed materials - Schmidt\, V (Ulm)
DTSTART:20100331T150000Z
DTEND:20100331T160000Z
UID:TALK23993@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:A stochastic network model is developed which describes the 3D
  morphology\nof the pore system in fibre-based materials. Such materials a
 re used e.g.\nfor the so-called gas diffusion layer (GDL) in polymeric fue
 l cells. In \nthe pore space of GDL essential transport processes take pla
 ce\, like the\ndiffusion of oxygen and hydrogen\, respectively\, towards t
 he electrochemically\nactive sites\,or the drainage of produced water.\n\n
 Recently\, various models for the solid phase of GDL\, in particular for\n
 the fibre system itself\, have been developed where the pore space is \nco
 nsidered as complementary set. However\, this indirect description of \npo
 re space often leads to very complex geometric structures\, i.e.\, it is \
 ndescribed by huge sets of voxels\, which make numerical simulations of \n
 transport processes quite complicated and computer time consuming\, \nespe
 cially for large domains.\n\nIn the present talk\, a mathematical model fo
 r random geometric graphs\nis developed\, representing the pore space dire
 ctly. It can be applied e.g. \nto investigate transport processes in GDL o
 n a large scale. We first model\nthe vertex set of the graph by a stack of
  2D point processes\, which can\nphysically be interpreted as pore centres
 . Each pore centre is then marked \nby its pore size. In the second step\,
  the edge set of the graph is constructed\,\nwhere the vertices are connec
 ted using tools from graph theory and MCMC simulation. \n\nThe model param
 eters are statistically fitted to real 3D data gained by means \nof synchr
 otron tomography. Finally\, the stochastic network model is validated by\n
 considering physical characteristics of GDL like their tortuosity\, i.e.\,
  the\ndistribution of shortest path lengths through the material relative 
 to its thickness.\n\nThe talk is based on joint research with W. Lehnert\,
  I. Manke and R. Thiedmann.\n
LOCATION:Seminar Room 2\, Newton Institute Gatehouse
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