Sn-120 homologous levels via the Sb-123((p)over-right-arrow,alpha)Sn-120 reaction: Experimental evidence and microscopic calculations

The Sb-123(p(->), alpha)Sn-120 reaction has been studied in a high resolution measurement at incident energy of 24 MeV using a polarized proton source and a Q3D spectrometer. The differential cross sections and asymmetries for transitions to levels of Sn-120 homologous to the lowest energy states of In-119 have been measured and interpreted in terms of the experimental differential cross sections and asymmetries of the parent In-119 states, on the basis of the weak-coupling model. Several (17) states of the Sn-120 residual nucleus, not previously reported in the literature, have been detected and spins and parities have been proposed for seven of them, while parities have been proposed for five other previously known levels. In order to analyze the transitions populating the homologous levels, for both differential cross sections and asymmetries, microscopic DWBA calculations have been performed using spectroscopic amplitudes obtained from a shell-model study

Rebound of a confined granular material: combination of a bouncing ball and a granular damper.

A ball dropped over a solid surface bounces several times before a complete stop. The bouncing can be reduced by introducing a liquid into the ball; however, the first rebound remains largely unaffected by the fluid. Granular materials can also work as dampers. We investigated the rebound of a container partially filled with a given mass of grains mi. During the collision, the kinetic energy of the container is partially transferred to the grains, the rebound is damped, and the fast energy dissipation through inter-particle collisions and friction decreases the bouncing time dramatically. For grain-filled cylinders, a completely inelastic collision (zero rebound) is obtained when mi≥1.5εomc, where εo and mc are the coefficient of restitution and mass of the empty container. For grain-filled spheres, the first rebound is almost undamped, but the second collision is completely inelastic if mi>>mc. These findings are potentially useful to design new granular damping systems