We investigate the photoinduced relaxation dynamics of Cr atoms embedded into superfluid helium nanodroplets. One- and two-color resonant two-photon ionization (1CR2PI and 2CR2PI, respectively) are applied to study the two strong ground state transitions z(7)P(2,3,4)° ← a(7)S3 and y(7)P(2,3,4)° ← a(7)S3. Upon photoexcitation, Cr* atoms are ejected from the droplet in various excited states, as ...

This paper addresses the generation and control of oil droplets in rolling piston type refrigerant compressors at speeds greater than 5000 RPM. This work is part of the development of a variable speed compressor which addresses the problem of critically low oil sump levels that can occur at these extreme speeds. This paper identifies the dominant mechanism of oil droplet generation based on exp...

In this contribution further development of our in-house FEM based parallel 3D simulation tool FeatFlow will be presented. In particular, we give an insight into the recent developments of the Level Set based multiphase module, which has been extended with high order (Q2) discretization to increase the robustness and accuracy of the arising prediction tool for the simulation of monodisperse dro...

Electrowetting-on-dielectric (EWOD) actuation enables digital (or droplet) microfluidics where small packets of liquids are manipulated on a two-dimensional surface. Due to its mechanical simplicity and low energy consumption, EWOD holds particular promise for portable systems. To improve volume precision of the droplets, which is desired for quantitative applications such as biochemical assays...

In droplet microfluidics, aqueous droplets are typically separated by an oil phase to ensure containment of molecules in individual droplets of nano-to-picoliter volume. An interesting variation of this method involves bringing two phospholipid-coated droplets into contact to form a lipid bilayer in-between the droplets. These interdroplet bilayers, created by manual pipetting of microliter dro...

In this paper, we present a novel method to generate ultra-small droplets via volatile component evaporation. By regulating the composition of the binary solvent, the volume ratio of the high saturated vapor pressure component, and the flow rate ratio of the two phases, monodisperse ultra-small water or nonvolatile organic droplets can be formed. This method is flexible, versatile, and compatib...

In this research, the results of comparative analysis of a single fuel droplet evaporation models are presented. Three well-known evaporation models including Spalding, Borman-Johnson and Abramzon-Sirignano models are analyzed using Computational Fluid Dynamic (CFD). The original Spalding model is extended to consider the effects of the Stefan flow, unsteady vaporization, and variable propertie...

Background: Based on previous chemical analyses of insect tarsal adhesives, we prepared 12 heterogeneous synthetic emulsions mimicking the polar/non-polar principle, analysed their microscopical structure and tested their adhesive, frictional, and rheological properties. Results: The prepared emulsions varied in their consistency from solid rubber-like, over soft elastic, to fluid (watery or oi...

We describe a method for creating discrete femtolitre-scale water-in-oil droplets on demand, based solely on a geometrically induced reduction in oil/water interfacial area at microfabricated junction orifices. This on-demand generation method is driven by self-shear of droplets due to interfacial tension induced forces resulting from a localized transition in microchannel height. The magnitude...