Evaporation of a small water droplet sessile on inclined surfaces

2022 ◽  
Vol 184 ◽  
pp. 122330
Author(s):  
Zhenhai Pan ◽  
Yu Wang
Keyword(s):  
Water Droplet ◽  
Small Water ◽  
Inclined Surfaces

scholarly journals Cantilever-Droplet-Based Sensing of Magnetic Particle Concentrations in Liquids

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4758 ◽  
Author(s):  
Wilson Ombati Nyang’au ◽  
Andi Setiono ◽  
Maik Bertke ◽  
Harald Bosse ◽  
Erwin Peiner
Keyword(s):  
Water Droplet ◽  
Water Evaporation ◽  
Ambient Conditions ◽  
Evaporation Time ◽  
Particle Count ◽  
Microcantilever Sensors ◽  
Small Water ◽  
Monodispersed Particles ◽  
Sensing Applications ◽  
Cantilever Sensor

Cantilever-based sensors have attracted considerable attention in the recent past due to their enormous and endless potential and possibilities coupled with their dynamic and unprecedented sensitivity in sensing applications. In this paper, we present a technique that involves depositing and vaporizing (at ambient conditions) a particle-laden water droplet onto a defined sensing area on in-house fabricated and commercial-based silicon microcantilever sensors. This process entailed the optimization of dispensing pressure and time to generate and realize a small water droplet volume (Vd = 49.7 ± 1.9 pL). Moreover, we monitored the water evaporation trends on the sensing surface and observed total evaporation time per droplet of 39.0 ± 1.8 s against a theoretically determined value of about 37.14 s. By using monodispersed particles in water, i.e., magnetic polystyrene particles (MPS) and polymethyl methacrylate (PMMA), and adsorbing them on a dynamic cantilever sensor, the mass and number of these particles were measured and determined comparatively using resonant frequency response measurements and SEM particle count analysis, respectively. As a result, we observed and reported monolayer particles assembled on the sensor with the lowest MPS particles count of about 19 ± 2.

scholarly journals A ciliate memorizes the geometry of a swimming arena

2016 ◽  
Vol 13 (118) ◽  
pp. 20160155 ◽  
Author(s):  
Itsuki Kunita ◽  
Tatsuya Yamaguchi ◽  
Atsushi Tero ◽  
Masakazu Akiyama ◽  
Shigeru Kuroda ◽  
...  
Keyword(s):  
Intracellular Calcium ◽  
Water Droplet ◽  
Adaptive Behaviour ◽  
Small Water ◽  
Short Period ◽  
Reversal Frequency ◽  
Slow Rise ◽  
Swimming Trajectories ◽  
Shape And Size

Previous studies on adaptive behaviour in single-celled organisms have given hints to the origin of their memorizing capacity. Here we report evidence that a protozoan ciliate Tetrahymena has the capacity to learn the shape and size of its swimming space. Cells confined in a small water droplet for a short period were found to recapitulate circular swimming trajectories upon release. The diameter of the circular trajectories and their duration reflected the size of the droplet and the period of confinement. We suggest a possible mechanism for this adaptive behaviour based on a Ca 2+ channel. In our model, repeated collisions with the walls of a confining droplet result in a slow rise in intracellular calcium that leads to a long-term increase in the reversal frequency of the ciliary beat.

Laser Beam-Hygroscopic Aerosol Interactions

1977 ◽  
Vol 99 (2) ◽  
pp. 281-286 ◽  
Author(s):  
G. E. Caledonia ◽  
J. D. Teare
Keyword(s):  
Steady State ◽  
Laser Beam ◽  
Water Droplet ◽  
Atmospheric Aerosol ◽  
Phase Shifts ◽  
Time Dependent ◽  
Small Water ◽  
Steady State Solutions

A model for the prediction of the temperature and vapor fields created about a small water droplet undergoing irradiation by a laser beam has been developed. Time-dependent and steady-state solutions of the model are discussed. Estimates of characteristic phase shifts to be expected in propagating through standard atmospheric aerosol distributions are also presented. While the model is quite general, the calculations are limited to DF laser wavelengths.

Microenvironmental Modification by Small Water Droplet Evaporation

1976 ◽  
Vol 15 (8) ◽  
pp. 858-867 ◽  
Author(s):  
Fred V. Nurnberger ◽  
George E. Merva ◽  
James B. Harrington
Keyword(s):  
Water Droplet ◽  
Droplet Evaporation ◽  
Small Water

Dynamic Behavior of a Small Water Droplet Impact Onto a Heated Hydrophilic Surface

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
El-Sayed R. Negeed ◽  
M. Albeirutty ◽  
Sharaf F. AL-Sharif ◽  
S. Hidaka ◽  
Y. Takata
Keyword(s):  
Dynamic Behavior ◽  
Water Droplet ◽  
High Speed ◽  
Heated Surface ◽  
Droplet Diameter ◽  
Video Camera ◽  
Surface Wettability ◽  
Hydrodynamic Characteristics ◽  
Small Water ◽  
Hot Surface

The aim of this study is to investigate the influence of the surface wettability on the dynamic behavior of a water droplet impacting onto a heated surface made of stainless steel grade 304 (Sus304). The surface wettability is controlled by exposing the surfaces to plasma irradiation for different time periods (namely, 0.0, 10, 60, and 120 s). The experimental runs were carried out by spraying water droplets on the heated surface where the droplet diameter and velocity were independently controlled. The droplet behavior during the collision with the hot surface has been recorded with a high-speed video camera. By analyzing the experimental results, the effects of surface wettability, contact angle between impacting droplet and the hot surface, droplet velocity, droplet size, and surface superheat on the dynamic behavior of the water droplet impacting on the hot surface were investigated. Empirical correlations are presented describing the hydrodynamic characteristics of an individual droplet impinging onto the heated hydrophilic surfaces and concealing the affecting parameters in such process.

scholarly journals Enhancement of Sensitivity and Accuracy of Micro/Nano Water Droplets Detection Using Galvanic-Coupled Arrays

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4500 ◽  
Author(s):  
Rekha Goswami Shrestha ◽  
Tatsuya Ando ◽  
Yukihiro Sakamoto ◽  
Jin Kawakita
Keyword(s):  
Contact Angle ◽  
Water Droplet ◽  
High Speed ◽  
Current Response ◽  
Water Droplets ◽  
Galvanic Current ◽  
Moisture Sensor ◽  
Average Value ◽  
Small Water ◽  
Working Principle

A moisture sensor has been reported that detects invisibly small water droplets and distinguishes their particle size with high accuracy and high speed. This sensor uses narrow lines of dissimilar metals as electrodes, arranged with gaps of 0.5 to 10 μm. The working principle for this sensor is that it measures the galvanic current generated when a water droplet forms a bridge-like structure between the electrodes. In addition, the surface of the sensor was controlled by using hydrophilic polymer, GL, and hydrophobic polymer, PMMA. The study of the relationship between the contact angle, projected area of water droplets and current response from the sensor with a modified surface showed that in the case of GL, the contact angle was small (wettability increased) and the average value and distribution of the projected water droplet area and the sensor’s response increased. This enhanced the sensor’s sensitivity. On the other hand, in the case of PMMA, the contact angle was large (wettability decreased), the area of the water droplet and its distribution became small and the accuracy of discriminating the water droplet’s diameter by the sensor enhanced. Therefore, by rendering sensor’s surface hydrophilic and hydrophobic, the sensitivity and accuracy of the sensor could be enhanced.

Why Can Water Droplets Move Smoothly Even on Statically Hydrophilic Surfaces?

2020 ◽  
Vol 20 (8) ◽  
pp. 5211-5216
Author(s):  
Satoshi Nakamura ◽  
Brandon Becher-Nienhaus ◽  
Takayuki Miyamae ◽  
Atsushi Hozumi
Keyword(s):  
Water Droplet ◽  
Contact Angle Hysteresis ◽  
Sol Gel ◽  
Hybrid Films ◽  
Conformational States ◽  
Droplet Motion ◽  
Small Water ◽  
Hydrophilic Surfaces ◽  
Dry Conditions ◽  
The Impact

Studies on hydrophilic surfaces showing excellent water sliding properties are very rare, despite the numerous practical advantages they offer. One of the authors has recently developed a smooth, transparent and sufficiently-thick hydrophilic film with low contact angle hysteresis (5°) and small water tilt angles (6 ± 2°) through a simple sol–gel reaction of 2-[methoxy (ethyleneoxy)10propyl]trimethoxysilane (PEG-M) and tetraethoxysilane (TEOS). However, the origins of these unusual water sliding properties have not been clearly identified. As such, the impact of the addition of TEOS acting as a “nanospacer” or the identity of PEG terminal functional groups on the final static/dynamic wetting properties needs to be explored. In this study, we investigated the orientational/conformational states of PEG chains in PEG-M/TEOS and [hydroxy(ethyleneoxy)8–12propyl]triethoxysilane (PEG-OH)/TEOS hybrid films under wet and dry conditions using sum-frequency generation (SFG) spectroscopy. We found that PEG-M/TEOS hybrid film surfaces had no marked differences in the conformational states of PEG chains under wet or dry conditions, resulting in excellent water sliding properties as there was no energy barrier for water droplet motion. In contrast, PEG chains were completely disordered after contact with water in the PEG-OH/TEOS hybrid films due to hydration effects. This large conformational change between the liquid/solid and gas/solid interface at the three-phase contact line resulted in an unfavorable energetic barrier for water droplet motion, leading to the poor water sliding properties. TEOS did not physically work as a “nanospacer,” but chemically worked as a binder to endow practically useful properties, such as good adhesion and versatility in substrates used, to our hybrid films.

Quantitative energy-filtered electron diffraction

1994 ◽  
Vol 52 ◽  
pp. 992-993
Author(s):  
R. Vincent
Keyword(s):  
Electron Diffraction ◽  
Inelastic Scattering ◽  
Dynamic Range ◽  
Electron Optics ◽  
Surface Layers ◽  
High Brightness ◽  
Inclined Surfaces ◽  
Perfect Symmetry ◽  
Amorphous Surface ◽  
The Ideal

Microanalysis and diffraction on a sub-nanometre scale have become practical in modern TEMs due to the high brightness of field emission sources combined with the short mean free paths associated with both elastic and inelastic scattering of incident electrons by the specimen. However, development of electron diffraction as a quantitative discipline has been limited by the absence of any generalised theory for dynamical inelastic scattering. These problems have been simplified by recent innovations, principally the introduction of spectrometers such as the Gatan imaging filter (GIF) and the Zeiss omega filter, which remove the inelastic electrons, combined with annual improvements in the speed of computer workstations and the availability of solid-state detectors with high resolution, sensitivity and dynamic range.Comparison of experimental data with dynamical calculations imposes stringent requirements on the specimen and the electron optics, even when the inelastic component has been removed. For example, no experimental CBED pattern ever has perfect symmetry, departures from the ideal being attributable to residual strain, thickness averaging, inclined surfaces, incomplete cells and amorphous surface layers.

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