Capillary forces are involved in a variety of natural phenomena, ranging from droplet breakup to the physics of clouds. The forces from surface tension can also be exploited in industrial applications provided the length scales involved are small enough. Recent experimental investigations showed how to take advantage of capillarity to fold planar structures into three-dimensional configurations...

When using appropriate surfactants, oil and aqueous foam can be intimately mixed without the foam being destroyed. In this Letter, we show that a foam, initially free of oil, can draw an oil drop under the action of capillary forces and stretch it through the aqueous network. We focus on the suction of oil by a single horizontal foam channel, known as a Plateau border. In such confined channels...

Highly viscous silicone oils within a wide range of volumes were left to spread on smooth horizontal substrates to investigate the effects of capillarity on viscous gravity spreadings under the condition of complete wetting. The study was centered on the intermediate asymptotic behavior, where the details of the initial liquid distribution are irrelevant. We detected small but appreciable depar...

This article addresses the hydrodynamic limit of the Boltzmann equation to the compressible Euler equations of gas dynamics. An exact summation of the Chapman–Enskog expansion originally given by A. Gorban and I. Karlin is the key to the analysis. An appraisal of the role of viscosity and capillarity in the limiting process is then given where the analogy is drawn to the limit of the Korteweg –...

Applications of hemp fibers, as a promising natural material in the textile field, mostly require improved fiber properties. In this paper, oxidation fibers with potassium permanganate was applied to reduce amount non-cellulosic substances and moisture sorption; introduce functional groups increase capillarity; make finer, softer suitable for application sport wears. The changes sorption proper...

The manipulation of microscopic objects is challenging because of high adhesion forces, which render macroscopic gripping strategies unsuitable. Adhesive footpads of climbing insects could reveal principles relevant for micro-grippers, as they are able to attach and detach rapidly during locomotion. However, the underlying mechanisms are still not fully understood. In this work, we characterize...

The numerical technique called upstream differencing, applied to mobility terms in Darcy’s law for steam and liquid flow in the geothermal simulators TOUGH and MULKOM, is shown to lead to numerical boundary layers in the equations for steady vertical steam-liquid counterflow. These boundary layers are found to be very narrow, and to act in the same way as capillary boundary layers, providing re...

Biomolecular folding and function are often coupled. During molecular recognition events, one of the binding partners may transiently or partially unfold, allowing more rapid access to a binding site. We describe a simple model for this fly-casting mechanism based on the capillarity approximation and polymer chain statistics. The model shows that fly casting is most effective when the protein u...