The influence of frequency, volume, and viscosity on the ultrasonic atomization threshold of sessile droplets.

In this research, we present a study on the atomization threshold (ATh) of sessile droplets, analyzing its relationship with the excitation frequency fexc (55-48 kHz), droplet volume Vdrop (1-100 μl), and droplet viscosity μ (1-6 mPa⋅s). The investigation focused on the atomization thresholds using ultrasonic excitation of distilled water droplets and water- polyethylene glycol (PEG)-8000 mixtures deposited on vibrating surfaces. The obtained results are compared with previously reported theoretical models.

On the dynamics of a big drop in acoustic levitation.

The acoustic levitation of a drop is a complex process that needs a high-intensity non-linear acoustic field; the sound pressure level has to be sufficient to raise the drop but not too large to avoid its atomization, limiting the maximum size of a levitated drop. In this paper, we present an experimental study of big drops levitation with a volume up to 166±2μl and with an effective diameter 6.82±0.

Boom-bust population dynamics increase diversity in evolving competitive communities.

The processes and mechanisms underlying the origin and maintenance of biological diversity have long been of central importance in ecology and evolution. The competitive exclusion principle states that the number of coexisting species is limited by the number of resources, or by the species' similarity in resource use. Natural systems such as the extreme diversity of unicellular life in the oceans provide counter examples.