The interplay of crack hopping, delamination and interface failure in drying nanoparticle films

Films formed through the drying of nanoparticle suspensions release the build-up of strain through a variety of different mechanisms including shear banding, crack formation and delamination. Here we show that important connections exist between these different phenomena: delamination depends on the dynamics of crack hopping, which in turn is influenced by the presence of shear bands. We also show that delamination does not occur uniformly across the film. As cracks hop they locally initiate the delamination of the film which warps with a timescale much longer than that associated with the hopping of cracks. The motion of a small region of the delamination front, where the shear component of interfacial crack propagation is believed to be enhanced, results in the deposition of a complex zig-zag pattern on the supporting substrate

How soft substrates affect the buckling delamination of thin films through crack front sink-in

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Response functions of the 4 pi detector ORION to 10-70 MeV neutrons

The neutron detection performances of the 4 pi ORION counter were investigated with monoenergetic neutron beams delivered by the Louvain-la-Neuve facility. Two responses are supplied by such a counter: a prompt response, arising from the slowing down of neutrons within the liquid scintillator contained in the detector, and a delayed response corresponding to the subsequent capture of the neutrons by Gd nuclei: with which the detector is loaded. Two experimental methods were used, allowing one to probe the responses for different neutron energies. Despite the large size of the detector, the prompt response is observed to be very similar to that exhibited by small cells. For both responses, a reasonable overall agreement is found between the data and the predictions of Monte-Carlo simulations. The timing resolution. of the order of 3 ns, makes this detector suitable for time-of-flight methods in applications requiring a high detection efficiency while accepting a moderate energy resolution. (C) 1998 Elsevier Science B.V. All rights reserved