In the present study, a molecular tagging technique was developed to achieve simultaneous measurements of droplet size, flying velocity and temperature of “in-flight” droplets in a spray flow. Phosphorescent molecules, which can be turned into long-lasting glowing marks upon excitation by photons of appropriate wavelength, were premixed in the water droplets and served as the tracers for the qu...

Local contact line pinning prevents droplets from rearranging to minimal global energy, and models for droplets without pinning cannot predict their shape. We show that experiments are much better described by a theory, developed herein, that does account for the constrained contact line motion, using as an example droplets on tilted plates. We map out their shapes in suitable phase spaces. For...

For original submission and image(s), see ARM Research Highlights http://www.arm.gov/science/highlights/ Research Highlight Aerosol spectra under marine stratus are often bimodal and attributable to cloud processes. Sizes at the minima between the modes have inferred supersaturations (S) of nearby clouds (Hoppel et al. 1985, 1994). This was based on the principle that the lower critical S (Sc) ...

In this work, a droplet microfluidic device integrated with droplet sorting function was presented for single cancer cell encapsulations and protease activity measurements. Individual cells were encapsulated into aqueous droplets at flow focusing junction under jetting conditions. Droplets with cells encapsulated inside are larger than other empty droplets, enabling effective droplet sorting th...

Liquid eutectic Pt-Si droplets, migrating across a Si(100) surface due to an applied temperature gradient, interact measurably with surface steps. An analysis of the interaction yields a critical size of hundreds of nanometers below which droplets are constrained to move parallel to monolayer steps. Bunches of closely spaced steps are capable of guiding larger, micron-sized droplets. This steer...

We present static and dynamical properties of linear vortices in 4He droplets obtained from density functional calculations. By comparing the adsorption properties of different atomic impurities embedded in pure droplets and in droplets where a quantized vortex has been created, we suggest that Ca atoms should be the dopant of choice to detect vortices by means of spectroscopic experiments.

Droplets emitting surface-active chemicals exhibit chemotaxis toward low-pH regions. Such droplets are self-propelled and navigate through a complex maze to seek a source of acid placed at one of the maze's exits. In doing so, the droplets find the shortest path through the maze. Chemotaxis and maze solving are due to an interplay between acid/base chemistry and surface tension effects.

The butterfly universe photo was made using water sprayed on glass that had been treated with Dupont’s Rain X, which allows the droplets to be much larger than normal. The droplets become wide-angle lenses when you place an object underneath the sprayed glass. The droplets are then photographed with a macro lens. In this picture, I placed an 8 10 photo of a monarch butterfly underneath the glas...

The distribution of droplets in a plane Hagen-Poiseuille flow of dilute suspensions has been measured by a special LDA technique. This method assumes a well defined relation between the velocity of the droplets and their lateral position in the channel. The measurements have shown that the droplet distribution is non-uniform and depends on the viscosity ratio between the droplets and the carrie...

ABSTRACT We demonstrate a droplet-based microfluidic device in which in-droplet magnetic bead separation is performed in continuous-flow. Two droplets containing different solution for the magnetic bead separation are generated in pair-wise manner. Sequential fusion of droplets occurs by a geometrical structure. The magnetic beads are deflected by externally applied magnetic force from one side...