TY  - JOUR
A1  - Pieper, Martin
A1  - Klein, Peter
T1  - Numerical solution of the heat equation with non-linear, time derivative-dependent source term
JF  - International Journal for Numerical Methods in Engineering
N2  - The mathematical modeling of heat conduction with adsorption effects in coated metal structures yields the heat equation with piecewise smooth coefficients and a new kind of source term. This term is special, because it is non-linear and furthermore depends on a time derivative. In our approach we reformulated this as a new problem for the usual heat equation, without source term but with a new non-linear coefficient. We gave an existence and uniqueness proof for the weak solution of the reformulated problem. To obtain a numerical solution, we developed a semi-implicit and a fully implicit finite volume method. We compared these two methods theoretically as well as numerically. Finally, as practical application, we simulated the heat conduction in coated aluminum fibers with adsorption in the zeolite coating. Copyright © 2010 John Wiley & Sons, Ltd.
Y1  - 2010
U6  - http://dx.doi.org/10.1002/nme.2937
SN  - 0029-5981
VL  - 84
IS  - 10
SP  - 1205
EP  - 1221
PB  - Wiley
CY  - Chichester
ER  - 
TY  - JOUR
A1  - Baumgartner, Werner
A1  - Fidler, Florian
A1  - Weth, Agnes
A1  - Habbecke, Martin
A1  - Jakob, Peter
A1  - Butenweg, Christoph
A1  - Böhme, Wolfgang
T1  - Investigating the locomotion of the sandfish in desert sand using NMR-Imaging
JF  - PLOS ONE
N2  - The sandfish (Scincus scincus) is a lizard having the remarkable ability to move through desert sand for significant distances. It is well adapted to living in loose sand by virtue of a combination of morphological and behavioural specializations. We investigated the bodyform of the sandfish using 3D-laserscanning and explored its locomotion in loose desert sand using fast nuclear magnetic resonance (NMR) imaging. The sandfish exhibits an in-plane meandering motion with a frequency of about 3 Hz and an amplitude of about half its body length accompanied by swimming-like (or trotting) movements of its limbs. No torsion of the body was observed, a movement required for a digging-behaviour. Simple calculations based on the Janssen model for granular material related to our findings on bodyform and locomotor behaviour render a local decompaction of the sand surrounding the moving sandfish very likely. Thus the sand locally behaves as a viscous fluid and not as a solid material. In this fluidised sand the sandfish is able to “swim” using its limbs.
KW  - magnetic resonance imaging
KW  - body limbs
KW  - swimming
KW  - lizards
KW  - deserts
Y1  - 2008
U6  - http://dx.doi.org/10.1371/journal.pone.0003309
SN  - 1932-6203
VL  - 3
IS  - 10
PB  - Plos
CY  - San Francisco, California, US
ER  -