Selective Laser Sintering of Passive Dynamic Ankle-Foot Orthoses

Passive dynamic ankle-foot orthoses (AFO’s) are used to improve gait performance in those with various neuromuscular disorders. An important design characteristic of passive dynamic AFOs is the storage and release of elastic energy within its structure to help satisfy the energetic demands of walking. Thus, minimizing energy dissipation through internal friction is a fundamental criterion for selecting the appropriate AFO material. This study compared the mechanical damping of a carbon-fiber AFO to three geometrically identical AFO’s fabricated using selective laser sintering with different materials. Mechanical damping characteristics ranked the materials as Nylon 11 (best), followed by DuraformTM PA and DuraformTM GF (worst).Mechanical Engineerin

Dissipative vortex solitons in 2D-lattices

We report the existence of stable symmetric vortex-type solutions for two-dimensional nonlinear discrete dissipative systems governed by a cubic-quintic complex Ginzburg-Landau equation. We construct a whole family of vortex solitons with a topological charge S = 1. Surprisingly, the dynamical evolution of unstable solutions of this family does not alter significantly their profile, instead their phase distribution completely changes. They transform into two-charges swirl-vortex solitons. We dynamically excite this novel structure showing its experimental feasibility.Comment: 4 pages, 20 figure

Modeling of droplet breakup in a microfluidic T--shaped junction with a phase--field model

A phase--field method is applied to the modeling of flow and breakup of droplets in a T--shaped junction in the hydrodynamic regime where capillary and viscous stresses dominate over inertial forces, which is characteristic of microfluidic devices. The transport equations are solved numerically in the three--dimensional geometry, and the dependence of the droplet breakup on the flow rates, surface tension and viscosities of the two components is investigated in detail. The model reproduces quite accurately the phase diagram observed in experiments performed with immiscible fluids. The critical capillary number for droplet breakup depends on the viscosity contrast, with a trend which is analogous to that observed for free isolated droplets in hyperbolic flow