Mechanical failure: Imaging cracks in hostile regimes.

Our understanding of the physical world has progressed hand in hand with our ability to observe it. For instance, computer tomography (CT) — which was originally developed for medical imaging — has been instrumental in the non-destructive testing of materials. In CT, a digital three-dimensional replica of the object under observation is reconstructed from hundreds or thousands of twodimensional projections (radiographs) collected at different illumination angles using X-rays, neutrons or other penetrating wave beams. Because the images are collected non-destructively, CT can be applied repeatedly to follow how the structure of a material changes over time. In fact, it is now possible to MECHANICAL FAILURE