scholarly journals Effect of a surface tension gradient on the slip flow along a superhydrophobic air-water interface

2018 ◽  
Vol 3 (3) ◽  
Author(s):  
Dong Song ◽  
Baowei Song ◽  
Haibao Hu ◽  
Xiaosong Du ◽  
Peng Du ◽  
...  
Keyword(s):  
Surface Tension ◽  
Slip Flow ◽  
Surface Tension Gradient ◽  
Water Interface ◽  
Air Water Interface

From Surface Tension to Molecular Distribution: Modeling Surfactant Adsorption at the Air–Water Interface

Langmuir ◽  
2021 ◽  
Vol 37 (7) ◽  
pp. 2237-2255 ◽  
Author(s):  
Mengsu Peng ◽  
Timothy T. Duignan ◽  
Cuong V. Nguyen ◽  
Anh V. Nguyen
Keyword(s):  
Surface Tension ◽  
Surfactant Adsorption ◽  
Water Interface ◽  
Molecular Distribution ◽  
Distribution Modeling ◽  
Air Water Interface

Surface active properties at the air–water interface of β-casein and its fragments derived by plasmin proteolysis

1989 ◽  
Vol 56 (3) ◽  
pp. 487-494 ◽  
Author(s):  
Michael Wilson ◽  
Daniel M. Mulvihill ◽  
William J. Donnelly ◽  
Brian P. Gill
Keyword(s):  
Surface Tension ◽  
Water Interface ◽  
Active Protein ◽  
Drop Volume ◽  
V Protein ◽  
Proteose Peptone ◽  
Rate Determining Step ◽  
Surface Active Properties ◽  
Air Water Interface ◽  
Surface Active

Summaryβ-Casein, was enzymically modified by incubation with plasmin to yield γ-caseins and proteose peptones. Whole γ-, γ1-, γ2/γ3-caseins and whole proteose peptone (pp) were isolated from the hydrolysate mixture. The time dependence of surface tension at the air-water interface of solutions of β-casein and its plasmin derived fragments, at concentrations of 10−1 to 10−4% (w/v) protein, pH 7.0, was determined, at 25 °C, using a drop volume apparatus. The ranking of the proteins with respect to rate of reduction of surface tension, during the first rate determining step, at 10-2% (w/v) protein, was γ2/γ3 ≫ pp > whole γ- > γ1- > β-casein. The ranking of the proteins with respect to surface pressures attained after 40 min (π40) was concentration dependent. γ2/γ3-Caseins were found to be very surface active, decreasing surface tension rapidly and giving a high π40. γ1 Casein decreased surface activity somewhat faster than β-casein, but generally reached a lower π40. Whole γ-casein reflected the properties of both γ1 and γ2/γ3-caseins. Proteose peptone was found to decrease surface tension rapidly during the initial rate determining step; it gave a relatively high π40 at a bulk phase concentration of 10−3% (w/v) protein, but, it was the least surface active protein at 10−1 and 10−2% (w/v) protein.

Observations on the locomotion of post-larval and juvenile flying fish

1990 ◽  
Vol 70 (2) ◽  
pp. 311-320 ◽  
Author(s):  
John Davenport
Keyword(s):  
Surface Tension ◽  
Surface Roughness ◽  
Reynolds Numbers ◽  
Maximum Speed ◽  
Tail Flick ◽  
Horizontal Distance ◽  
Water Interface ◽  
Flying Fish ◽  
Air Water Interface ◽  
Air Penetration

Post-larval specimens of Hirundichthys affinis are capable of jumping out of water, but the pectoral and pelvic fins are not extended when in air. Penetration through the air/ water interface demands a force to overcome surface tension which is similar in magnitude to the force required for the jump itself. However, post-larvae do not produce the single propulsive tail flick which powers the jump until most of the animal has passed through the interface. The post-larva emerges at an angle close to 45°, thus maximising the horizontal distance travelled before re-entry.Whether swimming slowly (4 body lengths s-1), or at maximum speed (36 body lengths s-1), post-larvae swim with the pectoral and pelvic fins extended. Calculations show that fast swimming post-larvae operate at Reynolds’ numbers of about 4×103, where surface roughness and projections decrease rather than increase drag.

Influence of pH on the surface and foaming properties of aqueous silk fibroin solutions

Soft Matter ◽  
2020 ◽  
Vol 16 (15) ◽  
pp. 3695-3704 ◽  
Author(s):  
Xiuying Qiao ◽  
Reinhard Miller ◽  
Emanuel Schneck ◽  
Kang Sun
Keyword(s):  
Surface Tension ◽  
Silk Fibroin ◽  
Bubble Coalescence ◽  
Foaming Properties ◽  
Water Interface ◽  
Interfacial Layers ◽  
Air Water Interface ◽  
Influence Of Ph

Silk fibroin (SF) adsorbs at the air/water interface, reduces the surface tension, and forms interfacial layers suppressing bubble coalescence and stabilizing foam.

Preparation of a new lignin-based anionic/cationic surfactant and its solution behaviour

RSC Advances ◽  
2015 ◽  
Vol 5 (4) ◽  
pp. 2441-2448 ◽  
Author(s):  
Mingsong Zhou ◽  
Wenli Wang ◽  
Dongjie Yang ◽  
Xueqing Qiu
Keyword(s):  
Surface Tension ◽  
Cationic Surfactant ◽  
Anionic Surfactant ◽  
Water Interface ◽  
Air Water Interface ◽  
Solution Behaviour

The lignin-based cationic/anionic surfactant CA-SLs have a stronger ability to lower the surface tension at the air/water interface compared with SL–PEG, but a weaker one than CTAB.

Adsorption of Hydrophobically Modified Poly(acrylic acid) Sodium Salt at the Air/Water Interface by Combined Surface Tension and X-ray Reflectivity Measurements

Langmuir ◽  
1999 ◽  
Vol 15 (6) ◽  
pp. 2112-2119 ◽  
Author(s):  
Frédéric Millet ◽  
Michael Nedyalkov ◽  
Benjamin Renard ◽  
Patrick Perrin ◽  
Françoise Lafuma ◽  
...  
Keyword(s):  
Surface Tension ◽  
Acrylic Acid ◽  
Sodium Salt ◽  
Water Interface ◽  
X Ray ◽  
Hydrophobically Modified ◽  
Acid Sodium Salt ◽  
Air Water Interface ◽  
Poly Acrylic Acid

Numerical Simulation of Two-Phase Slug Flows in Microchannels

2009 ◽  
Author(s):  
A. Mehdizadeh ◽  
S. A. Sherif ◽  
W. E. Lear
Keyword(s):  
Surface Tension ◽  
Slug Flow ◽  
Stokes Equations ◽  
Pressure Fluctuations ◽  
Water Interface ◽  
Liquid Slug ◽  
Complex Flow ◽  
Two Phase ◽  
Air Water Interface ◽  
Slug Flows

In this paper the Navier-stokes equations for a single liquid slug have been solved in order to predict the circulation patterns within the slug. Surface tension effects on the air-water interface have been investigated by solving the Young–Laplace equation. The calculated interface shape has been utilized to define the liquid slug geometry at the front and tail interfaces of the slug. Then the effects of the surface tension on the hydrodynamics of the two-phase slug flow have been compared to those where no surface tension forces exist. The importance of the complex flow field features in the vicinity of the two interfaces has been investigated by defining a non-dimensional form of the wall shear stress. The latter quantity has been formulated based on non-dimensional parameters in order to define a general Moody friction factor for typical two-phase slug flows in microchannels. Moreover, the hydrodynamics of slug flow formation has been examined using computational fluid dynamics (CFD). The volume-of-fluid (VOF) method has been applied to monitor the growth of the instability at the air-water interface. The lengths of the slugs have been correlated to the pressure fluctuations in the mixing region of the air and water streams at an axisymmetric T-junction. The main frequencies of the pressure fluctuations have been investigated using the Fast Fourier Transform (FFT) method.

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