A variational problem for three fluids in which gravitational and surface tension forces are in equilibrium is studied using sets of finite perimeter and functions of bounded variation. Existence theorems are proven which imply the existence of an axisymmetric floating drop. This problem has been studied previously as a free boundary problem for axisymmetric capillary surfaces by Elcrat, Neel a...

Evaporation of a liquid drop surrounded by either vapor the same fluid, or and air, is usually attributed to diffusion -- which, however, does not apply former setting, as pure fluids do diffuse. The present paper puts forward an additional mechanism, one that applies both settings. It shown disparities between in terms their pressure chemical potential give rise flow. Its direction depends on ...

In this work, biphenyl and biphenyl oxide were extracted by direct single drop microextraction (direct-SDME) and analyzed by gas chromatography flame ionization detection. The extraction occurred by suspending a 7 μL drop of toluene (as extracting solvent) containing acetonaphton (as internal standard) from the tip of a microsyringe in direct-SDME, respectively. The effect of different paramete...

A novel approach based on ionic liquid-single-drop microextraction (IL-SDME) online coupling with capillary electrophoresis (CE) was used to determine a toxic alkaloid--colchicine. The IL-SDME procedure was optimized by extraction solvent, drop volume controlling, sample volume and pH, extraction time, and ionic strength. Under optimum conditions, enrichment factor was as much as 41-fold with a...

A novel and low solvent consumption method for the sensitive determination of fungicide residues in wine samples is proposed. Analytes were extracted by dispersive liquid-liquid microextraction (DLLME) and further determined by gas chromatography-mass spectrometry (GC-MS). Under optimized conditions, a binary mixture of acetone and 1-undecanol (0.5 and 0.05 mL, respectively) was used to extract...

A new finite element level set method is developed to simulate the interface motion. The normal velocity of the moving interface can depend on both the local geometry, such as the curvature, and the external force such as that due to the flux from both sides of the interface of a material whose concentration is governed by a diffusion equation. The key idea of the method is to use an interface-...