When a liquid droplet impacts hot solid surface, enough vapor may be generated under it to prevent its contact with the solid. The minimum temperature for this so-called Leidenfrost effect occur is termed temperature, or dynamic when velocity non-negligible. We observe wetting drying and levitation dynamics of impacting on an (isothermal) smooth sapphire surface using high-speed total internal reflection imaging, which enables us base up about 100 nm above substrate surface. By method we are...

A drop impacting a smooth solid surface heated above the saturation temperature can either touch it (contact boiling) or not (film boiling), depending on temperature. The heat transfer is greatly reduced in latter case by insulating vapour layer under drop. In contrast to previous studies, here we use relatively poor thermally conducting glass surface. Using total internal reflection method, visualise wetting dynamics of We discover new touch-down process, which liquid–solid contact occurs...

Significance From critically affecting the performance of an aircraft to droplet-based additive manufacturing, solidification impacting droplets influences a wide range industrial applications; thus, deeper fundamental understanding droplet is necessary. In this work, we reveal and rationalize peculiar freezing morphology originating from complex interplay between droplet-scale hydrodynamics phase-transition effects at sufficiently high substrate undercooling. The direct visualization...

We experimentally investigate the nucleation of surface nanobubbles on PFDTS-coated silicon as a function specific gas dissolved in water. In each case, we restrict ourselves to equilibrium conditions (c = 100%, Tliquid Tsubstrate). Not only is nanobubble strong type, but there also exists an optimal system temperature ∼35 −40 °C where maximized, which weakly dependent type. find that contact angle radius curvature for all types investigated. Fitting this data allows us describe line tension...

When a liquid drop is placed on highly superheated surface, it can be levitated by its own vapour. This remarkable phenomenon referred to as the Leidenfrost effect. The thermally insulating vapour film results in severe reduction of heat transfer rate compared experiments at lower surface temperatures, where direct contact with solid surface. A commonly made assumption that this isothermal, which least questionable for materials low thermal conductivity, resulting an overestimation...

We study how ambient conditions change the Leidenfrost temperature (<italic>T</italic>_L) and metastability range below <italic>T</italic>_L.

Reduction of the ambient pressure changes boiling behavior impacting ethanol drops on a heated substrate as observed by contact area measurements (insets). With decreasing pressure, we find widening transition regime, while T${}_{L\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}d\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}f\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}s\phantom{\rule{0}{0ex}}t}$ stays roughly constant.

The compression of soft elastic matter and biological tissue can lead to creasing, an instability where a surface folds sharply into periodic self-contacts. Intriguingly, the unfolding upon releasing strain is usually not perfect: small scars remain that serve as nuclei for creases during repeated compressions. Here we present creasing experiments with sticky polymer surfaces, using confocal microscopy, which resolve contact line region folding occurs. It found tension induces second fold,...

An experimental study is performed to investigate the influence of crystal growth on contact line behavior a droplet an undercooled surface. We show effect that growing nucleus has arrest and underlying dependence nucleation rate. Finally, based classical theory scaling relations for spreading, we calculate temporal evolution solidifying area.

To develop and validate a tool for automatic selection of the slice minimal hiatal dimensions (SMHD) segmentation urogenital hiatus (UH) in transperineal ultrasound (TPUS) volumes.Manual SMHD UH was performed TPUS volumes 116 women with symptomatic pelvic organ prolapse (POP). These data were used to train two deep-learning algorithms. The first algorithm trained provide an estimation position SMHD. Based on this estimation, selected fed into second algorithm, which UH. From segmentation,...

Drops close to a hot solid surface can be prevented from making contact by the vapour generation in between them. This so-called Leidenfrost effect occurs at minimal plate temperature which is referred as temperature. In spray cooling, were one uses impacting drops cool down solid, this very undesirable: layer forms an isolating and prevents effective heat transfer drop solid. We study phenomenon single liquid nitrogen on smooth sapphire prism using high-speed frustrated total internal...

In many applications, it is crucial to control the heat transfer rate of impacting drops on a heated plate. When solid exceeds so-called Leidenfrost temperature, an drop prevented from contacting plate by its own evaporation. But decrease in resulting cooling efficiency yet not quantitatively understood. Here, we experimentally study impact such water smooth surfaces various substances. We demonstrate that, contrast previous results for other liquids, exhibits spray vertical direction when...

Droplets can be levitated by their own vapour when placed onto a superheated plate (the Leidenfrost effect). It is less known that the effect likewise observed over liquid pool (superheated with respect to drop), which study case here. Emphasis on an asymptotic analysis in limit of small evaporation numbers, indeed proves realistic one for millimetric-sized drops (i.e. where radius drop order capillary length). The global shapes are found resemble ‘superhydrophobic drops’ follow from...

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Abstract A fresh and frozen high-quality patient bio-sample is required in molecular medicine for the identification of disease-associated mechanism at levels. common cooling procedure immersing tissue enclosed a vial coolant such as liquid nitrogen. This not user friendly laborious reducing lag time from excision to freezing depends on logistic organizational structure within hospital. Moreover snapfreezing must be done soon possible after preserve quality tests. Herein, we report an...

An elastic material that experiences strong compression can exhibit sharp surface folds, often seen in growing tissues or swelling gels. We resolve how self-adhesion affects both morphology and bifurcation behavior of the adhesive crease.

Interleaving fins can significantly increase the heat transfer by increasing effective area per unit base area. The are separated uniformly a gap, which is filled with flow medium to control flux. flux between plates depends strongly on thermal conductivity of fin material and them as well dimensions. In earlier studies empirical fitting method used determine total effectiveness fins. However, it required complete characterization for each new set operating conditions. this paper, simplified...

Injecting an insoluble gas into a liquid results in subcooling of the liquid, due to forced evaporation bubble. While this ``bubble cooling'' effect causes losses energy and mass fluidized-bed reactors, it also can be exploited as alternative, simple strategy for removing heat from liquid. Previous studies have assumed rate bubbles independent degree subcooling, but study authors quantify bubble growth directly by high-speed imaging, disprove hypothesis. The expansion ratio is strong...