scholarly journals Holes and cracks in rigid foam films

2015 ◽  
Vol 774 ◽  
Author(s):  
P. C. Petit ◽  
M. Le Merrer ◽  
A.-L. Biance
Keyword(s):  
Active Material ◽  
Surface Elasticity ◽  
Classical Problem ◽  
Film Rupture ◽  
Rigid Foam ◽  
Foam Films ◽  
Rupture Dynamics ◽  
Foam Film ◽  
Surface Active Material

The classical problem of foam film rupture dynamics has been investigated when the film interfaces exhibit very high rigidity due to the presence of specific surfactants. Two new features are reported. First, a strong deviation from the well-known Taylor–Culick law is observed. Second, crack-like patterns can be visualized in the film; these patterns are shown to appear at a well-defined film shrinkage. The key role of surface-active material on these features is quantitatively investigated, pointing to the importance of surface elasticity to describe these fast dynamical processes and thus providing an alternative tool to characterize surface elasticity in conditions extremely far from equilibrium. The origin of the cracks and their consequences on film rupturing dynamics are also discussed.

336. Surface activity and proteins of milk

1946 ◽  
Vol 14 (3) ◽  
pp. 316-329 ◽  
Author(s):  
R. Aschaffenburg
Keyword(s):  
Milk Fat ◽  
Chemical Nature ◽  
Active Material ◽  
Milk Proteins ◽  
Residual Fraction ◽  
Total Milk ◽  
Surface Active ◽  
Surface Active Material ◽  
Dilution Curves

As moderate dilution causes little change in the surface tension of milk, it is shown to be advantageous to use σ-dilution curves in place of the σ-values of the undiluted fluid as a characteristic of the surface properties of milk. The complications arising from the presence of the milk fat are described, and it is suggested that the influence of the fat is of a physical rather than of a chemical nature. A study of the role of the various milk proteins shows the casein to be of great importance, whilst the heat-coagulable proteins have little influence. The serum obtained after removal of the casein and heat-coagulable proteins contains a residual fraction of protein-like material which is markedly surface active though constituting only about 3% of the total milk proteins. The surface-active material (σ-proteose) has been concentrated and isolated, and its properties are described in some detail.

The Role of Surface Transport in the Stability and Breakdown of Foams

1952 ◽  
Vol 5 (4) ◽  
pp. 697 ◽  
Author(s):  
WE Ewers ◽  
KL Sutherland
Keyword(s):  
Surface Tension ◽  
Foam Stability ◽  
Surface Film ◽  
High Surface ◽  
Active Material ◽  
Dominant Factor ◽  
Surface Transport ◽  
The Stability ◽  
Surface Active Material

A new theory of foam stability is proposed which demonstrates that the transport of substrate. accompanying a movement of the surface of the bubble film, is a dominant factor in the stability of foams and in the action of foam breakers. The surface moves from a region of low surface tension (high surface pressure) to a region of high surface tension. The surface tension gradients arise from disturbances which may be caused by mechanical or thermal shocks, or by the addition to the surface of particles, droplets, or vapour of a surface-active material. When the surface tension is highest at the centre of disturbance the film mill be stable ; when the surface tension is lowest at this point the surface film and hence the substrate will be moved away from this point and the film will rupture.

Role of Pristine and Acid-Functionalized Fullerene on Breaking Dye Aggregates and its Impact on the Efficiency of Solar Cells

2014 ◽  
Vol 67 (5) ◽  
pp. 819
Author(s):  
Syed Mujtaba Shah ◽  
Zafar Iqbal ◽  
Muzaffar Iqbal ◽  
Naila Shahzad ◽  
Amina Hana ◽  
...  
Keyword(s):  
Solar Cells ◽  
Zno Nanoparticles ◽  
Self Assembly ◽  
Zno Nanorods ◽  
Active Material ◽  
Dye Sensitized Solar Cells ◽  
Dye Sensitized ◽  
Transmission Electron ◽  
Sensitized Solar Cells

Porphyrin dyes have an inherent tendency to aggregate. This leads to a self-quenching phenomenon that hinders electron transfer to the conduction band of semiconductors in dye-sensitized solar cells. Self-quenching adversely affects the efficiency of solar cells. Here, we report the interaction of porphyrin with pristine and acid-functionalized fullerene molecules on the surface of ZnO nanoparticles under chemisorbed conditions. Chemisorption of porphyrin only on ZnO nanoparticles instigates aggregation of the porphyrin molecules. These aggregates can be effectively broken by chemisorbing fullerene molecules on the surface of the ZnO nanoparticles. This is due to self-assembly formation processes because of porphyrin–fullerene interactions. The nanohybrid material, consisting of ZnO nanorods, acid-functionalized porphyrin, and fullerene derivatives, was characterized by UV–visible spectroscopy, fourier transform infrared spectroscopy, fluorescence spectroscopy, and transmission electron microscopy. The material generates better performing dye-sensitized solar cells when compared with those fabricated from porphyrin-based photo-active material.

Letter to the Editor

PEDIATRICS ◽  
1974 ◽  
Vol 54 (4) ◽  
pp. 519-519
Keyword(s):  
Amniotic Fluid ◽  
Active Material ◽  
Hyaline Membrane Disease ◽  
Clinical Entity ◽  
Letter To The Editor ◽  
Hyaline Membrane ◽  
Surface Active ◽  
Surface Active Material

Dr. Stevenson's observations concerning the association of amniotic fluid aspiration and hyaline membrane disease is quite interesting. Very little work, that we are aware of, has been done since these articles were published (1955 to 1958) to follow tip this theory. However, much work has been done to clarify the etiology of hyaline membrane disease. It is now well accepted that this clinical entity is directly related to the degree of immaturity of the lungs and the presence or absence of surface active material.

Isolation and assay of dipalmityl lecithin in lung extracts

1964 ◽  
Vol 207 (2) ◽  
pp. 402-406 ◽  
Author(s):  
Elwyn S. Brown
Keyword(s):  
Phosphatidyl Choline ◽  
Trichloroacetic Acid ◽  
Cadmium Chloride ◽  
Active Material ◽  
Weight Basis ◽  
Alcohol Extract ◽  
Wet Weight ◽  
Surface Active ◽  
Surface Active Material ◽  
Surface Balance

Lung extracts were obtained by either mincing the lungs in saline or by washing the lung with saline through the trachea. The surface tensions of the extracts on compression to 10% of the original area in a surface balance decreased to 7.5 ± 2.1 dynes/cm for rabbits, 10.0 ± 1.8 dynes/cm for dogs, and 6.8 ± 3.8 dynes/cm for man. The surface-active material in the extracts was completely precipitated with trichloroacetic acid. Ethyl or methyl alcohol extracted the activity from the precipitate. By concentrating and chilling the alcohol extract, a very surface-active white precipitate was obtained which was identified as dipalmityl phosphatidyl choline by melting point, chemical analysis, and paper chromatography. Cadmium chloride also precipitated a surface-active complex from the alcohol extract which was identified chemically as dipalmityl phosphatidyl choline. The quantity of hydrolecithin extracted from the lungs was 0.09–0.18% on a wet weight basis. No evidence of the presence of sphingomyelin or other surface-active phospholipid was obtained.

Beta-receptors and surface active material flux in fetal lamb lung: female advantage

1987 ◽  
Vol 63 (2) ◽  
pp. 828-833 ◽  
Author(s):  
D. Warburton ◽  
L. Parton ◽  
S. Buckley ◽  
L. Cosico ◽  
T. Saluna
Keyword(s):  
Pulmonary Surfactant ◽  
Binding Capacity ◽  
Active Material ◽  
Degree Polynomial ◽  
Beta Adrenergic ◽  
Female Advantage ◽  
Beta Agonists ◽  
Beta Receptors ◽  
Surface Active ◽  
Surface Active Material

We correlated the ontogeny of pulmonary beta-adrenergic receptors with the onset of surface active material (SAM) flux into tracheal fluid of male and female chronically catheterized fetal lambs. SAM flux began between 0.82 and 0.85 gestation in the females and between 0.85 and 0.89 gestation in the males and matured more rapidly thereafter in the females than in the males (P less than 0.01). beta-Adrenergic receptor binding, using [3H]dihydroalprenolol as the ligand, was saturable, linear, and stereospecific. The order of potency of competitive beta-agonists was isoproterenol greater than norepinephrine greater than epinephrine. The maximal binding capacity (Bmax) of pulmonary beta-receptors approximately doubled between 0.84 and 0.89 gestation, coinciding with the onset of SAM flux. Bmax matured as a third degree polynomial function of gestational age in females (r = 0.9, P less than 0.001) but as a linear function in males (r = 0.8, P less than 0.005). Between 0.86 and 0.93 gestation, Bmax was 1.45-fold greater in females than males (P less than 0.001). The dissociation constant of beta-receptors was not influenced significantly by gender or gestation. We conclude that maturation of pulmonary beta-receptors coincides with the onset of SAM flux in fetal lambs and that both mature more rapidly in females. We speculate that pulmonary beta-receptor maturation and SAM flux are coregulated by hormonal factors. More rapid maturation of pulmonary beta-receptors and SAM flux in females may be a factor in the female advantage with regard to pulmonary surfactant maturation and the survival of premature neonates.

Isolation and chemical composition of surface-active material from human lung lavage

Lipids ◽  
1988 ◽  
Vol 23 (6) ◽  
pp. 551-558 ◽  
Author(s):  
T. Sadana ◽  
K. Dhall ◽  
S. N. Sanyal ◽  
A. Wali ◽  
R. Minocha ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Human Lung ◽  
Active Material ◽  
Lung Lavage ◽  
Surface Active ◽  
Surface Active Material

Paper 33: Hydrodynamics of Surface Films: Modelling Laws for Two-Phase Flows Containing Dilute Surfactant

1967 ◽  
Vol 182 (8) ◽  
pp. 320-329
Author(s):  
D. B. R. Kenning
Keyword(s):  
Open Channel ◽  
Adsorption Process ◽  
Active Material ◽  
Surface Adsorption ◽  
Open Channel Flow ◽  
Surface Films ◽  
Two Phase Flows ◽  
Two Phase ◽  
Surface Active ◽  
Surface Active Material

The presence of surface-active material may modify appreciably the flow patterns in two-phase flows. A frequently employed model for the surface adsorption process is used to derive similarity conditions for such flows. The limitations of this model are discussed in relation to the formation of surface films on open channel flow of water containing dilute surfactant.

Sign in / Sign up

Export Citation Format

Share Document