Background	Numerical Simulations	Collaboration
We are combining a particle code with dissolution reaction. In the discrete code particles are connected by springs with each other. Particles are dissolved using a linear rate law and calculating the chemical potential using surface energy, fluid pressure and elastic energy.  If the elastic network is stressed we observe surface roughening, propagation of anticracks and mode I fractures.	Movies:	Dr. Anders Malthe-Sörenssen, Department of Physics, University of Oslo Prof. Björn Jamtveit, Department of Geology, University of Oslo
Roughness around hole	Patterns I	Patterns II

Background	Physical Experiments	Collaboration
We developed a new apparatus, the ElaPso-Meter to investigate patterns that form during dissolution-precipitation creep. We use photoelasticity to determine the local differential stress and the direction of the axis of the eigenvalues during insitu experiments of dissolution/precipitation. An example is shown on the right where one can see compressive stress concentrations on the right side of the hole at the tip of a horizontal fracture. Crystal is stressed vertically.		Dr. Dag Dysthe, Department of Physics, University of Oslo
	Pictures of the setup. The picture on the left hand side shows the ElaPso-meter with a small NaCl crystal in the central chamber. A micrometer screw at the top pushes on a set of parallel springs that hold a fricionless piston that pushes on the sample. The apparatus also includes temperature control, a capacitance dilatometer and the possibility to raise the fluid pressure in the cell.  The picture on the right hand side shows the optical setup to measure the photoelasticity or birefringence in the sample.