scholarly journals Size-Dependent and Property-Independent Passive Microdroplet Sorting by Droplet Transfer on Dot Rails

Micromachines ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 513 ◽  
Author(s):  
Dong Yoon ◽  
Daiki Tanaka ◽  
Tetsushi Sekiguchi ◽  
Shuichi Shoji
Keyword(s):  
Surface Tension ◽  
Lateral Flow ◽  
High Potential ◽  
Laplace Pressure ◽  
Droplet Transfer ◽  
Sorting Method ◽  
Threshold Size ◽  
Size Dependent

A fully passive microdroplet sorting method is presented in this paper. On the rails with dot patterns, the droplets were sorted in different ways depending on their size. However, the effect of droplet properties on the threshold size of the sorting was eliminated. The droplet positions on two railways and the Laplace pressure of the droplets on the dot patterns allowed selective droplet transfer according to size. Different gaps between the rails altered the threshold size of the transfer. However, the threshold size was independent of the droplet’s surface tension and viscosity because the droplet transfer utilized only the droplet position and Laplace pressure without lateral flow to sort targets. This feature has a high potential for bio/chemical applications requiring categorization of droplet targets consisting of various mixtures as pre- or post-elements.

scholarly journals THRESHOLD SIZE FOR FLOWERING IN DIFFERENT HABITATS: EFFECTS OF SIZE-DEPENDENT GROWTH AND SURVIVAL

Ecology ◽  
1997 ◽  
Vol 78 (7) ◽  
pp. 2118-2132 ◽  
Author(s):  
Renate A. Wesselingh ◽  
Peter G. L. Klinkhamer ◽  
Tom J. de Jong ◽  
Laurence A. Boorman
Keyword(s):  
Growth And Survival ◽  
Threshold Size ◽  
Size Dependent ◽  
Dependent Growth

scholarly journals Size-Dependent Phase Transformation during Gas Atomization Process of Cu–Sn Alloy Powders

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 245 ◽  
Author(s):  
Hao Pan ◽  
Hongjun Ji ◽  
Meng Liang ◽  
Junbo Zhou ◽  
Mingyu Li
Keyword(s):  
Phase Transformation ◽  
Nucleation Theory ◽  
Gas Atomization ◽  
Atomization Process ◽  
Cu6sn5 Phase ◽  
Lotus Leaf ◽  
Threshold Size ◽  
Size Dependent ◽  
Droplet Sizes ◽  
Transient Nucleation

For binary element atomization, it is essential to investigate the phase transformation from liquid to solid as a functions of the droplet sizes, as well as the reaction competitiveness, during gas atomizing solidification of their nuclei. In the present work, a series of phase transformations of undercooled Cu (60.9 wt.%)/Sn droplets were analyzed when atomized by pressure gas. The results indicated that the microstructures of the obtained powders and their morphologies were highly relevant to the droplet size. According to the phase characteristics analyzed by the microstructural observations in combination with the transient nucleation theory, powders with sizes from 10 to 100 μm were divided into three categories, exhibiting lotus-leaf, island, and stripe morphologies. The competitive formation of Cu6Sn5 or Cu3Sn was also controlled by the droplet sizes, and a diameter of approximately 45 μm was identified as the threshold size. After heat treatment at 300 °C for 4 h, the powders consisted of a single η’ Cu6Sn5 phase. The obtained Cu6Sn5 phase powders can be used in the field of high-temperature applications as intermetallic balls for integrated chip interconnects.

Nanoindentation hardness of a Steigmann–Ogden surface bounding an elastic half-space

2018 ◽  
Vol 24 (9) ◽  
pp. 2754-2766 ◽  
Author(s):  
Xiaobao Li ◽  
Changwen Mi
Keyword(s):  
Surface Tension ◽  
Half Space ◽  
Surface Elasticity ◽  
Elastic Half Space ◽  
Indentation Hardness ◽  
Bending Rigidity ◽  
Size Dependent ◽  
Significant Difference ◽  
Nanoindentation Hardness ◽  
Membrane Stiffness

Previous studies demonstrate that, for nanostructures under transverse bending, the effective Young modulus is appreciably greater (in magnitude) than that of the same elements under axial loads. Therefore, in addition to the conventional residual surface tension and membrane stiffness, the curvature dependence of surface energy is desired for inhomogeneously strained nanostructures. In this paper, we aim to reevaluate the size-dependent nanoindentation hardness of an elastic half-space subjected to nanosized frictionless traction, through the use of both the curvature-independent Gurtin–Murdoch and the curvature-dependent Steigmann–Ogden models of surface elasticity. The nanoindentation problem is solved by the integration of Boussinesq’s method of displacement potentials and Hankel integral transforms. As examples, the effects of residual surface tension, membrane stiffness, and bending rigidity of the half-space boundary are parametrically analyzed in detail for a uniform circular pressure and a concentrated normal force. The observations in semianalytical calculations suggest a significant difference in the nanoindentation hardnesses predicted from the two popular models of surface mechanics. In most cases, the inclusion of bending rigidity results in smaller displacements and stresses, and therefore higher indentation hardness. Based on physically interpretable numerical values of surface material properties, we show that a curvature-dependent model of surface elasticity is required in order to characterize the size-dependent feature of nanoindentation problems correctly.

scholarly journals Anisotropic Spreading of Bubbles on Superaerophilic Straight Trajectories beneath a Slide in Water

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 798
Author(s):  
Chengxu Tu ◽  
Qincan Yang ◽  
Yeyu Chen ◽  
Yuhang Ye ◽  
Yukun Wang ◽  
...  
Keyword(s):  
Surface Tension ◽  
High Speed ◽  
Laplace Pressure ◽  
Anisotropic Behavior ◽  
Surface Tension Effect ◽  
Mineral Flotation ◽  
Nice Agreement ◽  
Application Potential ◽  
Novel Model ◽  
Contact Size

Although the bubble contacting a uniformly superaerophilic surface has caused concern due to its application potential in various engineering equipment, such as mineral flotation, very little is known about the mechanism of how the bubble spreads on a surface with anisotropic superaerophilicity. To unveil this mystery, we experimentally studied the anisotropic behavior of a bubble (2 mm in diameter) spreading on the superaerophilic straight trajectories (SALTs) of different widths (0.5 mm–5 mm) in water using a high-speed shadowgraphy system. The 1–3 bounces mostly happened as the bubble approached the SALTs before its spreading. It is first observed that the bubble would be split into two highly symmetrical sub-bubbles with similar migration velocity in opposite directions during the anisotropic spreading. Two essential mechanisms are found to be responsible for the anisotropic spreading on the narrow SALTs (W ≤ 2 mm with two subregimes) and the wide SALTs (W ≥ 3 mm with four subregimes). Considering the combined effect of the surface tension effect of SALT and Laplace pressure, a novel model has been developed to predict the contact size r(t) as a function of time. The nice agreement between this model and our experiments reconfirms that the surface tension effect and Laplace pressure prevail over the hydrostatic pressure.

scholarly journals The surface tension of surfactant-containing, finite volume droplets

2020 ◽  
Vol 117 (15) ◽  
pp. 8335-8343 ◽  
Author(s):  
Bryan R. Bzdek ◽  
Jonathan P. Reid ◽  
Jussi Malila ◽  
Nønne L. Prisle
Keyword(s):  
Surface Tension ◽  
Finite Volume ◽  
Climate Models ◽  
High Surface ◽  
Finite Size ◽  
Volume Ratio ◽  
Cloud Droplet ◽  
Reaction Rates ◽  
Hygroscopic Growth ◽  
Size Dependent

Surface tension influences the fraction of atmospheric particles that become cloud droplets. Although surfactants are an important component of aerosol mass, the surface tension of activating aerosol particles is still unresolved, with most climate models assuming activating particles have a surface tension equal to that of water. By studying picoliter droplet coalescence, we demonstrate that surfactants can significantly reduce the surface tension of finite-sized droplets below the value for water, consistent with recent field measurements. Significantly, this surface tension reduction is droplet size-dependent and does not correspond exactly to the macroscopic solution value. A fully independent monolayer partitioning model confirms the observed finite-size-dependent surface tension arises from the high surface-to-volume ratio in finite-sized droplets and enables predictions of aerosol hygroscopic growth. This model, constrained by the laboratory measurements, is consistent with a reduction in critical supersaturation for activation, potentially substantially increasing cloud droplet number concentration and modifying radiative cooling relative to current estimates assuming a water surface tension. The results highlight the need for improved constraints on the identities, properties, and concentrations of atmospheric aerosol surfactants in multiple environments and are broadly applicable to any discipline where finite volume effects are operative, such as studies of the competition between reaction rates within the bulk and at the surface of confined volumes and explorations of the influence of surfactants on dried particle morphology from spray driers.

Threshold Size for Flowering in Different Habitats: Effects of Size- Dependent Growth and Survival

Ecology ◽  
1997 ◽  
Vol 78 (7) ◽  
pp. 2118 ◽  
Author(s):  
Renate A. Wesselingh ◽  
Peter G. L. Klinkhamer ◽  
Tom J. de Jong ◽  
Laurence A. Boorman
Keyword(s):  
Growth And Survival ◽  
Threshold Size ◽  
Size Dependent ◽  
Dependent Growth
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