When a liquid drop impacts a solid surface, air is generally entrapped underneath. Using ultrafast x-ray phase-contrast imaging, we directly visualized the profile of an entrapped air film and its evolution into a bubble during drop impact. We identified a complicated evolution process that consists of three stages: inertial retraction of the air film, contraction of the top air surface into a ...

This study examined how user characteristics affect drop-off detection with the long cane. A mixed-measures design with block randomization was used for the study, in which 32 visually impaired adults attempted to detect the drop-offs using different cane techniques. Younger cane users detected drop-offs significantly more reliably (mean +/- standard deviation = 74.2% +/- 11.2% of the time) tha...

Observations are presented of several novel phenomena involved in the dynamics of a pendant drop of viscoelastic micellar fluid falling through air. Generally, when a drop falls a filament forms connecting it to the orifice; the filament eventually breaks due to an instability. The filament dynamics and instabilities reported here are very different from the standard Newtonian and non-Newtonian...

We address the dynamics of a drop with viscosity lh breaking up inside another fluid of viscosity h. We track the time evolution of the drop near snap-off in the experiments and then compare with a scaling theory developed for l 1. The theory is in excellent agreement with both the experiments and the previous simulations of Lister and Stone. Finally, we also investigate the l dependence of the...

In this paper, we propose a scheme to combine trajectory-based detection and body-based estimation to analyze human behavior in video scene. Our scheme is applied for a fast and automatic detection of pick-up/drop-off events within surveillance videos in indoor areas. A moving person is tracked globally using the mean-shift algorithm and modeled locally using an axis skeleton in a monocular vid...

Almost all dial-a-ride problems (DARP) described in the literature consist of designing optimal routes and schedules for n customers who specify pick-up and drop-off times. In this article we assume that the customer is mainly concerned with the drop-off time since it is the most important to the customer. Then based on the drop-off time specified by the customer and the customer’s location, a ...