THE observation that small pressure disturbances could be induced in the brachial artery and readily detected on radial arterial pressure records prompted the study of induced waves of two general types, impact transients' and forced sinusoidal waves. This report describes the method we have used to study "impact" waves and indicates the general nature of our findings. The interpretation of pul...

Mechanical properties of as-printed 316L stainless steel thin-walled structures obtained by directed energy deposition are investigated. In-situ tensile and fracture tests performed on small samples from a additively manufactured square section tube extracted with three different orientations respect to the part build direction. Despite strongly oriented microstructure resulting process, specim...

The origin and rapid diversification of flowering plants has puzzled evolutionary biologists, dating back to Charles Darwin. Since that time a number of key life history and morphological traits have been proposed as developmental correlates of the extraordinary diversity and ecological success of angiosperms. Here, I identify several innovations that were fundamental to the evolutionary labili...

We experimentally studied the propagation of coupled fluid stress waves and tube flexural waves generated through projectile impact along the axis of a water-filled tube. We tested mild steel tubes, 38–40 mm inner diameter and wall thicknesses of 0.8 mm, 6.4 mm, and 12.7 mm. A steel impactor was accelerated using an air cannon and struck a polycarbonate buffer placed on top of the water surface...

Polarization of low-lying excitonic bands in finite-size semiconducting single-walled carbon nanotubes (SWNTs) is studied by using quantum-chemical methodologies. Our calculations elucidate properties of cross-polarized excitons, which lead to the transverse optical absorption of nanotubes and presumably couple to intermediate-frequency modes recently observed in resonance Raman excitation spec...