Effects of surfactants or fat solvent on static pressure-volume hysteresis of excised dog lung

1962 ◽  
Vol 203 (4) ◽  
pp. 725-730 ◽  
Author(s):  
Seiichi Yoshida
Keyword(s):  
Surface Tension ◽  
Static Pressure ◽  
Pressure Level ◽  
Tween 20 ◽  
Trapped Air ◽  
Surface Active Agents ◽  
Surface Active ◽  
Volume Characteristics ◽  
Relationship Of ◽  
Intrabronchial Pressure

The static pressure-volume diagram of the lung was studied after the application of surface active agents to the airways of excised lobes of dog lungs. After rinsing of excised air-free lobes with saline or plasma, hysteresis obtained on air inflation and deflation was marked, but it was remarkably reduced after rinsing air-free lobes with surface active agents, 0.5% Tween-20 in saline, 0.5% octyl alcohol in plasma, or with petroleum ether. The reduced hysteresis was accompanied by a diminution in the amount of air remaining in the lobe on return to zero intrabronchial pressure level. The results of the surface tension-area relationship of lung extracts are consistent with those of the pressure-volume characteristics of lungs. These data indicate that the change in slope and position of the deflation curve resulting from fixing surface tension at about 25 dynes/cm, reduces hysteresis, in correspondence with the reduction of the volume of trapped air at zero intrabronchial pressure level.

Influence of Surfactants on the Dynamics of Fluid-Liquid Interfaces

2006 ◽  
Author(s):  
Dieter Bothe ◽  
Andreas Alke
Keyword(s):  
Surface Tension ◽  
Bubble Column ◽  
Dynamical Behavior ◽  
Jump Condition ◽  
Spatial Inhomogeneity ◽  
Two Phase ◽  
Surface Active Agents ◽  
Liquid Systems ◽  
Surface Active ◽  
Phase Fluid

In many two-phase fluid-liquid systems at least one phase contains surface active agents (surfactants for short) which are adsorbed preferentially at the interface Γ(t) due to minimization of free surface energy. Important examples are emulsification processes and bubbles rising in a bubble column through water containing a surfactant - unmeant as a contamination or by determined addition in order to increase the efficiency of the column. The adsorption of a surfactant at a fluid-liquid interface causes a decrease of the surface tension, depending on the area specific concentration cΓ of the adsorbed surfactant, i.e. σ=f(cΓ)(1) with a decreasing function f. The adsorbed surfactant is distributed on the interface due to convective and diffusive interfacial fluxes. The resulting spatial inhomogeneity leads to surface gradients of the surface tension, ∇Γσ(cΓ), which effect the hydrodynamics via the interfacial momentum jump condition [pI−S]nΓ=σκnΓ+∇Γσ(cΓ).(2) These additional so-called Marangoni stresses often result in a pronounced change of the dynamical behavior.

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.

Modifying of etching anisotropy of silicon substrates by surface active agents

Open Physics ◽  
2011 ◽  
Vol 9 (2) ◽  
Author(s):  
Krzysztof Rola ◽  
Irena Zubel
Keyword(s):  
Surface Tension ◽  
Aqueous Solutions ◽  
Alkaline Solution ◽  
Etch Rate ◽  
Butyl Alcohol ◽  
Silicon Substrates ◽  
Etching Solution ◽  
Surface Active Agents ◽  
Tert Butyl Alcohol ◽  
Surface Active

AbstractThe influence of alcohol additives on etch rate anisotropy of Si(hkl) planes has been studied. The etching processes were carried out in 3 and 5 M KOH aqueous solutions saturated and non-saturated with alcohols. Isopropanol, 1-propanol and tert-butanol were examined. It has been showed that the etching process cannot be controlled only by the surface tension of the solution. Saturation of the etching solution with alcohols modifies etch rate anisotropy, lowering the ratio of the etch rate of (110) and vicinal planes to the etch rate of (100) plane. The morphology of Si(hkl) planes etched in 3 M KOH solution saturated with tert-butyl alcohol has been studied in detail. Smooth (331) and (221) planes have been achieved in this solution. The (100) plane turned out to be densely covered by hillocks, opposite to the (100) plane etched in weak-alkaline solution saturated with isopropanol. To explain this phenomenon, the mechanism of hillocks formation on Si(100) surface has been proposed.

scholarly journals Density and surface tension of aqueous solutions of adjuvants used for tank-mixes with pesticides

2012 ◽  
Vol 58 (No. 12) ◽  
pp. 568-572 ◽  
Author(s):  
J. Janků ◽  
L. Bartovská ◽  
J. Soukup ◽  
M. Jursík ◽  
K. Hamouzová
Keyword(s):  
Surface Tension ◽  
Aqueous Solutions ◽  
Chemical Properties ◽  
Calculated Density ◽  
Surface Active Agents ◽  
Physico Chemical ◽  
Pesticide Formulations ◽  
Density Values ◽  
Surface Active

Adjuvants are surface active agents that are added to pesticide formulations or tank-mix to facilitate the mixing, application, or efficacy of these products. Addition of adjuvants changes the physico-chemical properties of spray liquid. In this work, we have focused in particular on surface tension and density of aqueous solutions of different adjuvants registered for mixing with herbicides. Eleven different adjuvants were subject of this study under laboratory conditions. An equation which enables determination of density of aqueous solutions in concentration range of 0–15 g/kg was designed. Average difference between the experimental and calculated density values amounts to ± 0.006%. The concentration dependence of surface tension was utilized to determine the critical micelle concentration (cmc). Evidently, the cmc of most tested adjuvants was lower than the amount recommended by manufacturer, especially in case of adjuvants Dedal 90 EC and Mero 33528. For adjuvant Trend 90 EC the recommended rate is even lower than that obtained for the cmc. Maximum reduction of the surface tension of water was achieved with adjuvants Silwet L-77 and Break Superb.    

scholarly journals THE INFLUENCE OF INTRAVENOUSLY ADMINISTERED SURFACE-ACTIVE AGENTS ON THE DEVELOPMENT OF EXPERIMENTAL ATHEROSCLEROSIS IN RABBITS

1951 ◽  
Vol 93 (4) ◽  
pp. 385-398 ◽  
Author(s):  
Aaron Kellner ◽  
James W. Correll ◽  
Anthony T. Ladd
Keyword(s):  
Blood Lipids ◽  
Great Increase ◽  
Tween 80 ◽  
Experimental Atherosclerosis ◽  
Blood Cholesterol ◽  
Intravenous Injections ◽  
Surface Active Agents ◽  
Surface Active ◽  
Relationship Of ◽  
The Relationship

A study was made of the relationship of blood lipids to the development of experimental atherosclerosis. Rabbits fed a diet containing cholesterol were found to develop hyperlipemia characterized by a great increase in blood cholesterol and a much lesser increase in blood phospholipids; after several weeks they manifested conspicuous atherosclerosis of the aorta, as has often been observed by others. Comparable rabbits fed the same diets containing added cholesterol were given in addition repeated intravenous injections of the surface-active agents Tween 80 and Triton A20; these animals developed hyperlipemia which was characterized by a great increase in blood cholesterol and an equivalent or even greater increase in phospholipids, and they had much less atherosclerosis than did the control rabbits fed cholesterol alone. In further experiments it was observed that repeated intravenous injections of Tween 80 did not result in resorption of previously induced atherosclerosis in rabbits. The findings are discussed in relation to the pathogenesis of natural and experimental atherosclerosis.

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