Power Wheelchair Navigation Assistance Using Wearable Vibrotactile Haptics.

People with severe disabilities often rely on power wheelchairs for moving around. However, if their driving abilities are affected by their condition, driving a power wheelchair can become very dangerous, both for themselves and the surrounding environment. This article proposes the use of wearable vibrotactile haptics for wheelchair navigation assistance.

Breaking of rotational symmetry in cylindrically bounded 2D electron plasmas and 2D fluids.

Off-axis final states of cylindrically bounded 2D fluids can develop from initially unstable, but cylindrically symmetric, 2D vorticity distributions. Experiments with electrons in a Malmberg-Penning trap, as well as 2D fluid simulations, demonstrated that such states result when the initial vorticity distribution is close to the boundary, while less extended distributions lead to on-axis states. A simple thermodynamic model, maximizing the entropy of a state consisting of a diffuse background surrounding a strong coherent vortex, is shown to quantitatively predict this bifurcation, while conserving circulation, angular momentum, and energy.