New Thermodynamics for Evaluating the Surface-phase Enrichment in the Lower Surface Tension Component

ChemPhysChem ◽  
2014 ◽  
Vol 15 (13) ◽  
pp. 2834-2843 ◽  
Author(s):  
M. Soledade C. S. Santos ◽  
João Carlos R. Reis
Keyword(s):  
Surface Tension ◽  
Lower Surface ◽  
Surface Phase ◽  
Lower Surface Tension

scholarly journals Investigation about wetting ability (surface tension) of water used for preparation of pesticide solutions

2021 ◽  
Vol 117 (3) ◽  
pp. 1
Author(s):  
Donyo Hristov GANCHEV
Keyword(s):  
Surface Tension ◽  
Water Source ◽  
Lower Surface ◽  
Flow Rates ◽  
Wetting Ability ◽  
Lower Resistance ◽  
Wax Content ◽  
Lower Surface Tension ◽  
Plant Surfaces

<p class="042abstractstekst">The investigation about surface tension of water used for preparation of pesticide solutions reveals it is quite diverse and changeable without any logical correlation towards location, time, and type of water source. Moreover, spraying with solutions with lower surface tension give bigger flow rates due to the lower resistance of fluid to the nozzles. The conducted trials show that plant surfaces with more rough texture require to be sprayed with pesticide solutions with lower surface tension. The wax content of the surfaces has no significant impact on surface tension requirement.</p><p> </p>

Experiments on the breakup of drop-impact crowns by Marangoni holes

2018 ◽  
Vol 844 ◽  
pp. 162-186 ◽  
Author(s):  
Abdulrahman B. Aljedaani ◽  
Chunliang Wang ◽  
Aditya Jetly ◽  
S. T. Thoroddsen
Keyword(s):  
Surface Tension ◽  
Lower Surface ◽  
High Viscosity ◽  
Solid Substrate ◽  
Immiscible Liquid ◽  
Hole Formation ◽  
Low Viscosity ◽  
Stress Changes ◽  
Lower Surface Tension ◽  
The Impact

We investigate experimentally the breakup of the Edgerton crown due to Marangoni instability when a highly viscous drop impacts on a thin film of lower-viscosity liquid, which also has different surface tension than the drop liquid. The presence of this low-viscosity film modifies the boundary condition, giving effective slip to the drop along the solid substrate. This allows the high-viscosity drop to form a regular bowl-shaped crown, which rises vertically away from the solid and subsequently breaks up through the formation of a multitude of Marangoni holes. Previous experiments have proposed that the breakup of the crown results from a spray of fine droplets ejected from the thin low-viscosity film on the solid, e.g. Thoroddsen et al. (J. Fluid Mech., vol. 557, 2006, pp. 63–72). These droplets can hit the inner side of the crown forming spots with lower surface tension, which drives a thinning patch leading to the hole formation. We test the validity of this assumption with close-up imaging to identify individual spray droplets, to show how they hit the crown and their lower surface tension drive the hole formation. The experiments indicate that every Marangoni-driven patch/hole is promoted by the impact of such a microdroplet. Surprisingly, in experiments with pools of higher surface tension, we also see hole formation. Here the Marangoni stress changes direction and the hole formation looks qualitatively different, with holes and ruptures forming in a repeatable fashion at the centre of each spray droplet impact. Impacts onto films of the same liquid, or onto an immiscible liquid, do not in general form holes. We furthermore characterize the effects of drop viscosity and substrate-film thickness on the overall evolution of the crown. We also measure the three characteristic velocities associated with the hole formation: i.e. the Marangoni-driven growth of the thinning patches, the rupture speed of the resulting thin films inside these patches and finally the growth rate of the fully formed holes in the crown wall.

Surfactant convertase action is not essential for surfactant film formation

1997 ◽  
Vol 273 (5) ◽  
pp. L907-L912 ◽  
Author(s):  
N. J. Gross ◽  
R. Veldhuizen ◽  
F. Possmayer ◽  
R. Dhand
Keyword(s):  
Surface Tension ◽  
Film Formation ◽  
Surface Film ◽  
Lower Surface ◽  
Diisopropyl Fluorophosphate ◽  
Surfactant Film ◽  
Surface Active ◽  
Lower Surface Tension ◽  
Surface Balance

A serine-active enzyme, “surfactant convertase,” is required for the conversion of surfactant from the tubular myelin (TM) form to the small vesicular (SV) form. This transformation involves at least two steps, the conversion of TM to a surface-active film at the air-fluid interface and the reorientation of the film into the surface-inactive SV form; we asked if convertase was required for the first of these steps. Rat and mouse TMs were pretreated with diisopropyl fluorophosphate (DFP) to inactivate endogenous convertase activity or with vehicle and then were analyzed for their ability to lower surface tension in vitro as an index of the conversion of TM to a surface film. DFP pretreatment did not alter the ability of TM preparations to lower surface tension, as assessed by pulsating bubble, and it did not affect the behavior of TM in a surface balance. In an experiment designed to test the ability of TM to feed a surface film to exhaustion, TMs that had been pretreated with DFP or vehicle performed similarly. These experiments show that convertase activity is not required for the conversion of TM to a monolayer and suggest, instead, that convertase acts at a post surface film stage.

Cosurfactants Lower Surface Tension of the Diglyceride/Water Interface:  A Molecular Dynamics Study

Langmuir ◽  
1996 ◽  
Vol 12 (10) ◽  
pp. 2570-2579 ◽  
Author(s):  
Aldert R. van Buuren ◽  
D. Peter Tieleman ◽  
Jacob de Vlieg ◽  
Herman J. C. Berendsen
Keyword(s):  
Molecular Dynamics ◽  
Surface Tension ◽  
Lower Surface ◽  
Water Interface ◽  
Lower Surface Tension

On the Wettability, Encapsulation and Surface Phase Transition in Monotectic Liquid Metallic Systems

2007 ◽  
Vol 537-538 ◽  
pp. 527-532 ◽  
Author(s):  
György Kaptay
Keyword(s):  
Phase Transition ◽  
Surface Tension ◽  
Liquid Metal ◽  
Lower Surface ◽  
Surface Phase ◽  
Surface Phase Transition ◽  
First Order ◽  
Interfacial Energies ◽  
Order Surface ◽  
Metallic Systems

In the present paper the wettability of a liquid metal by another liquid metal is studied theoretically, based on a recent model on interfacial energies in metallic systems. It appears that in all practical cases the liquid metal with a lower surface tension will perfectly wet (with a zero contact angle) the liquid metal with a higher surface tension practically at any temperature, and therefore will encapsulate it. As a result, the first order surface phase transition will start in monotectic metallic systems at 0 K. The phenomenon of the surface phase transition is considered in some details, based on a recent paper.

scholarly journals SPONTANEOUS DECREASE OF THE SURFACE TENSION OF SERUM. I

1922 ◽  
Vol 35 (4) ◽  
pp. 575-597 ◽  
Author(s):  
P. Lecomte du Noüy
Keyword(s):  
Surface Tension ◽  
Surface Layer ◽  
Lower Surface ◽  
Rapid Decrease ◽  
A Value ◽  
Characteristic Constant ◽  
Before And After ◽  
Ring Method ◽  
Lower Surface Tension ◽  
Prolonged Heat

1. Over 3,000 measurements of surface tension of sera have been made with the ring method, and they have yielded a new phenomenon, the spontaneous and rapid decrease of the surface tension of a serum in function of the time. 2. Generally, after 10 minutes the surface tension reaches a value which is practically constant. At least, the decrease is very much slower. After stirring, a rise occurs and a similar phenomenon takes place; but stability is not obtained as rapidly, requiring about 25 minutes. By stirring again, the same thing happens repeatedly, the slope of the curve being less marked each time, the rise in surface tension being slightly below each previous value, and the phenomenon undergoing a sort of damping. 3. An equation was established which expresses the experimental facts with an accuracy of about 0.2 per cent. It applies to the whole phenomenon, before and after stirring. It has only one characteristic constant, See PDF for Equation This formula, by simply changing t to c (concentration), expresses satisfactorily in general the phenomenon of adsorption in the surface layer; that is, the decrease in surface tension in function of the concentration. 4. Prolonged heat, at 55°C., and time seem to inhibit this phenomenon. 5. When precipitation occurs in a serum, the bottom of the liquid, which contains the precipitate, has the highest surface tension. When stirred, the surface tension rises a little every time. The upper part, clear, with lower surface tension, shows the reverse phenomenon; after every stirring, the surface tension becomes a little lower.

▾ Colfosceril palmitate (exosurf) – artificial surfactant for immature lungs

1991 ◽  
Vol 29 (12) ◽  
pp. 46.1-46
Keyword(s):  
Surface Tension ◽  
Respiratory Function ◽  
Distress Syndrome ◽  
Hyaline Membrane Disease ◽  
Lower Surface ◽  
Premature Babies ◽  
Hyaline Membrane ◽  
Lower Surface Tension ◽  
Reducing Substances ◽  
Artificial Surfactant

It has been known for about 30 years that lack of surface tension reducing substances (‘surfactant’) in the lungs of premature infants is largely responsible for the development of hyaline membrane disease or respiratory distress syndrome (RDS). About 50% of premature babies develop RDS, characteristically showing tachypnoea, chest retractions and worsening cyanosis. Many babies die of it or suffer complications. Mechanical ventilation is the main treatment, supporting respiratory function until maturing alveolar lining cells synthesise adequate surfactant. Despite its inherent risks it has proved very successful, but drugs which can lower surface tension in the lungs may improve outcome further.

Gas Exchange during Gas and Liquid Ventilation

1996 ◽  
Vol 11 (6) ◽  
pp. 313-325 ◽  
Author(s):  
Elisabeth A. Mates ◽  
Jacob Hildebrandt ◽  
Jacob Hildebrandt
Keyword(s):  
Surface Tension ◽  
Gas Exchange ◽  
Respiratory Distress ◽  
Distress Syndrome ◽  
Disease Process ◽  
Lower Surface ◽  
Liquid Ventilation ◽  
Pulmonary Physiology ◽  
Lung Functions ◽  
Lower Surface Tension

Liquid Ventilation with perfluorochemicals (PFC) violates many of our long-held assumptions about how the lung functions. However, the technique has been so successful in animal models of lung disease that it is currently being tested in clinical trials for the treatment of infant and acute (“adult”) respiratory distress syndrome in newborns, children, and adults. A common feature of both infant and acute respiratory distress syndromes is an inability of the lung's surfactant system to adequately lower surface tension, leading to regions of atelectasis. Liquid ventilation with PFC appears to ameliorate the disease process by lowering interfacial tension in the lung, opening regions of atelectasis, and improving gas exchange. To understand how gas exchange is successful during liquid ventilation requires careful re-evaluation of the assumptions underlying our current models of gas exchange physiology during normal gas ventilation. These assumptions must then be examined in light of the alterations in pulmonary physiology during liquid ventilation.

The Effect of Interfacial Waves on the Transition to Slug Flow

1994 ◽  
Vol 116 (3) ◽  
pp. 583-591 ◽  
Author(s):  
Eugene Kordyban ◽  
Abdul Hakim Okleh
Keyword(s):  
Surface Tension ◽  
Slug Flow ◽  
Lower Surface ◽  
Phase Flow ◽  
Closed Channel ◽  
Two Phase ◽  
Wave Growth ◽  
Surface Active Agents ◽  
Surface Active ◽  
Lower Surface Tension

It has been proposed by the authors that the transition to slug flow depends on the growth of waves in the two-phase flow and thus may predict if the laws of wave growth in closed channel are known. In this work, this proposition is tested by examining the highest waves and the transition to slug flow for air and water, air and water with surface tension reduced by addition of surface-active agents, air and water with increased viscosity by addition of corn syrup and air and ethanol. In each case it is found that the predicted transition to slug flow agrees well with experimental data. Neither a lower surface tension nor a higher viscosity has any effect on the transition to slug flow, but the use of surface active agents reduces the wave growth rate and causes the transition to slug flow to shift to higher gas velocities.

scholarly journals Surface tension of two weakly interacting liquid alloys

BIBECHANA ◽  
2012 ◽  
Vol 9 ◽  
pp. 103-112 ◽  
Author(s):  
RP Koirala ◽  
D Adhikari ◽  
BP Singh
Keyword(s):  
Surface Tension ◽  
Liquid Alloy ◽  
Lower Surface ◽  
Molten Alloy ◽  
Liquid Alloys ◽  
Molten State ◽  
Bulk Concentration ◽  
Weakly Interacting ◽  
Lower Surface Tension ◽  
The Ideal

We report surface tension of two weakly segregating alloys Al-Ga and Cd-In in molten state at temperatures of 1023 K and 800 K respectively using different approaches. Our analysis based on different assumptions reveal that the metal with lower surface tension tends to segregate on the surface of molten alloy and the metal with higher surface tension tends to segregate in the bulk. Different approaches predict consistency in the values of the surface tension of Al-Ga liquid alloy that increases with increase in bulk concentration of aluminium in the alloy with all values smaller than the ideal values. In Cd-In alloy the models reveal no such regularity in the surface tension; it varies slightly from the ideality. DOI: http://dx.doi.org/10.3126/bibechana.v9i0.7183 BIBECHANA 9 (2013) 103-112

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