The products of primary magma fragmentation finally revealed by pumice agglomerates

Following rapid decompression in the conduit of a volcano, magma breaks into ash- to block-sized fragments, powering explosive sub-Plinian and Plinian eruptions that may generate destructive pyroclastic falls and flows. It is thus crucial to assess how magma breaks up into fragments. This task is difficult, however, because of the subterranean nature of the entire process and because the original size of pristine fragments is modified by secondary fragmentation and expansion. New textural observations of sub-Plinian and Plinian pumice lapilli reveal that some primary products of magma fragmentation survive by sintering together within seconds of magma break-up. Their size distributions reflect the energetics of fragmentation, consistent with products of rapid decompression experiments. Pumice aggregates thus offer a unique window into the previously inaccessible primary fragmentation process and could be used to determine the potential energy of fragmentation.

Proximal Scaphoid Pole Reconstruction Utilizing Ipsilateral Proximal Hamate Autograft

Background: Fractures of the proximal pole of the scaphoid can be difficult to heal because of its limited vascular supply. Furthermore, nonunion with avascular necrosis and secondary fragmentation makes surgical reconstruction a challenging procedure. Method: We describe a technique and report the outcome of a proximal hamate autograft to treat a proximal pole scaphoid nonunion with avascular necrosis. Results: At 3.5 years post reconstruction, the patient remains asymptomatic with union of his scaphoid reconstruction without any evidence of scapholunate instability. Conclusion: Proximal hamate autograft is a useful technique for addressing proximal pole scaphoid nonunions with avascular necrosis.

Release from nanomaterials during their use phase: combined mechanical and chemical stresses applied to simple and multi-filler nanocomposites mimicking wear of nano-reinforced tires

We explore synergistic degradation, such as the mechanical/chemical/mechanical secondary fragmentation of rubber with multiple simultaneously embedded nanomaterials.