scholarly journals ПОВЕРХНОСТНОЕ НАТЯЖЕНИЕ СМЕСЕЙ ПОЛИАКРИЛАМИДА С НЕИОННЫМИ ПОВЕРХНОСТНО-АКТИВНЫМИ ВЕЩЕСТВАМИ (SURFACE TENSION OF MIXTURES OF POLYACRYLAMIDE WITH NON-IONIC SURFACE-ACTIVE SUBSTANCES)

2020 ◽  
Author(s):  
Zhanar Ospanova ◽  
Nurgeldy Abeu ◽  
Bekzada Tasenova
Keyword(s):  
Surface Tension ◽  
Surface Activity ◽  
Lower Surface ◽  
Polymer Mixtures ◽  
Foaming Agents ◽  
Low Concentrations ◽  
Order Of Magnitude ◽  
Surface Active ◽  
Active Substances ◽  
Surface Tension Isotherms

The aim of this work is to study the surface properties of mixtures of polyacrylamide (PAA) with nonionic surfactants. In this work, kinetic curves of a decrease in the surface tension of PAA were obtained in the concentration range of 1 * 10-5 ÷ 1 * 10-3 base mol/l, and on the basis of the equilibrium values of surface tension, isotherms of the surface tension of aqueous solutions of composite mixtures based on polyacrylamide (PAA) were obtained with surfactants - nonionic amphoteric N, N – dimethyldodecylamine N-oxide (DMDAO) and nonionic cocoamidopropyl betaine (CAPB). It has been shown that compositions of surfactant with a polymer in the region of low concentrations have a lower surface tension, which is associated with an increase in the surface activity of surfactant - PAA composites in comparison with individual surfactants. The surface tension isotherms were used to determine the critical micelle concentration (CMC) of the surfactant and surfactant-PAA compositions. It was found that the addition of a polymer to a surfactant lowers the CMC by an order of magnitude for the DMDAO - PAA mixture and by more than two orders of magnitude for the CAPB - PAA mixture, which also indicates an increase in the surface activity of the surfactant - polymer mixtures. The use of PAA compositions with surfactants as stabilizers for foams and emulsions opens up prospects for the development of effective emulsifiers and foaming agents.

Surface-Active Substances of the Guinea Pig Tubotympanum: A Chemical and Physical Analysis

1981 ◽  
Vol 89 (2) ◽  
pp. 307-316 ◽  
Author(s):  
Michael D. Maves ◽  
Gajanan S. Patil ◽  
David J. Lim
Keyword(s):  
Surface Tension ◽  
Guinea Pig ◽  
Surface Activity ◽  
Eustachian Tube ◽  
Lipid Fraction ◽  
Pooled Analysis ◽  
Current Evidence ◽  
Physical Analysis ◽  
Surface Active ◽  
Active Substances

An attempt to describe the nature of the surface-active substances of the eustachian tube lining layer that influence normal tubal function was undertaken. Under sterile conditions, guinea pig tubotympanic washings were collected, centrifuged, and pooled. Analysis of the pooled lavages using standard surface chemistry techniques confirmed the presence of significant surface-tension-lowering activity in the mucous lining layer of the eustachian tube, but the surface pressure obtained is neither as great nor displays the same degree of hysteresis as pulmonary surfactant. Following separation into aqueous and lipid fractions, measurable amounts of surface activity can be found in both isolates. The chemical composition and concentration of the lipid fraction, and its relative contribution to the surface activity of the tubotympanic washings, however, is smaller and radically different from the phospholipids found in surfactant. A significantly higher concentration of protein was recovered in comparison with the lipid portion, and it was observed that the surface activity of the total washings and the aqueous phase bore remarkable similarities. Although the surface-tension-lowering properties of the tubal lining layer may be the consequence of a combined synergistic action of the lipid and protein moieties, we believe that the current evidence points toward the proteins as being the primary tubal surface-tension-lowering substances.

The effect of the variation of surface tension with temperature on the motion of bubbles and drops

1967 ◽  
Vol 27 (2) ◽  
pp. 361-366 ◽  
Author(s):  
J. F. Harper ◽  
D. W. Moore ◽  
J. R. A. Pearson
Keyword(s):  
Surface Tension ◽  
Boundary Conditions ◽  
Small Bubble ◽  
Detailed Calculation ◽  
Order Of Magnitude ◽  
Surface Active ◽  
Bubble Rising ◽  
Special Case ◽  
Active Substances

The boundary conditions at the surface of a small bubble rising in a liquid are examined theoretically, and it is shown by order-of-magnitude arguments, which are confirmed by detailed calculation in a special case, that although surfacetension gradients must always exist around the bubble, they are too small to affect the motion appreciably unless surface-active substances are present. This is because gradients of surface tension imply gradients of temperature in a pure liquid, and these turn out to be always small near the bubble if they tend to zero at large distances from it. The same is true for drops of one fluid in another.

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.

The structure and function of the spiracular gill of the fly Taphrophila vitripennis

1957 ◽  
Vol 147 (926) ◽  
pp. 90-120 ◽  
Keyword(s):  
Surface Tension ◽  
Moisture Content ◽  
Internal Pressure ◽  
Normal Pressure ◽  
Structure And Function ◽  
Respiratory Organ ◽  
Surface Active ◽  
And Function ◽  
Pupal Cuticle ◽  
Active Substances

The spiracular gill is a pupal structure, but it is the chief respiratory organ of the adult of Taphrophila before the pupal cuticle is shed. At the pupa-adult moult, the epidermis and blood in the spiracular gill are completely isolated from the living insect by two cuticles between which is the moulting fluid. A few hours after the isolation of the tissue, the epidermis of most parts of the gill begins to dissociate, the cells become rounded, separate away from the cuticle and from one another, and in due course form loose clumps usually far from the gill walls. The tissue isolated in the gill repairs cuts and tears in the gill walls with a tanned cuticle. At 16 to 18° C the competence of the isolated tissue to repair damage to the gill walls lasts about 14 days. The tissue is isolated 8 to 9 days before the emergence of the adult, and it repairs the gill up to 5 days after the insect has shed it and flown away. The isolated tissue tolerates complete dehydration and high temperatures. In water the isolated tissue of gills previously dried for 70 days over phosphorus pentoxide and heated when dry to 103° C for 2 h, or to 130° C for 30 min, successfully repaired wounds. The epidermis of the adult and larva of Taphrophila also repairs wounds after complete dehydration. The epidermis of other insects is shown to exhibit a similar tolerance to dehydration even when no such tolerance is shown by the insect: the epidermis of some insects that are killed when they lose about 20% of their moisture content will repair wounds after complete dehydration if dried rapidly. The gill of Taphrophila has a plastron that is not wetted at pressures below about 0⋅3 atm above normal pressure, and it is only wetted by surface active substances that reduce the surface tension to about 25 dyn/cm. Apart from its plastron, the gill is not an effective respiratory organ. The gill walls are not rigid. In water, the internal pressure maintains turgidity and maximum surface area necessary for the efficient functioning of the plastron. The internal pressure of intact and unscarred gills is 4⋅3 atm. When the gill is torn or cut open, blood and cells spurt out and there is an immediate equilization of internal and hydrostatic pressures. A clot is rapidly formed at the site of the injury. The increase in the mechanical strength of the clot outpaces the increase in the internal pressure brought about by water that diffuses into the gill. In a number of other Tipulidae beside Taphrophila blood and epiderm is are isolated in the respiratory horn or the spiracular gill at the pupa-adult moult. In some of these, such as the species of Lipsothrix , the epidermis does not dissociate nor separate from the cuticle but becomes syncytial and remains closely attached to the cuticle.

PHOSPHATASE OF RABBIT POLYMORPHONUCLEAR LEUCOCYTES

1949 ◽  
Vol 27e (5) ◽  
pp. 290-307 ◽  
Author(s):  
D. M. Cram ◽  
R. J. Rossiter
Keyword(s):  
Alkaline Phosphatase ◽  
Enzyme Activity ◽  
Acid Phosphatase ◽  
Bile Salts ◽  
Polymorphonuclear Leucocytes ◽  
Alkyl Sulphate ◽  
Low Concentrations ◽  
Activity Curve ◽  
Surface Active ◽  
Active Substances

Rabbit polymorphonuclear leucocytes contain an active phosphatase that readily hydrolyzes disodium phenyl phosphate. The pH activity curve of the enzyme was found to have two maxima, one in the region of pH 10 and the other in the region of pH 5. The alkaline phosphatase was much more active than the acid phosphatase. The concentration of alkaline phosphatase in rabbit white cells was approximately one thousand times that of the enzyme in the serum. Under the conditions of study, the alkaline phosphatase activity was proportional to the concentration of the enzyme. The effect of substrate concentration on the enzyme activity was studied and the Michaelis constant (Ks) determined. An excess of substrate inhibited the enzyme. The course of the reaction was linear with time for the first 60 min.; after 90 min. the activity fell off faster than would be expected if the reaction were of the first order.Magnesium and glycine, in low concentrations, caused an increase in the enzyme activity, whereas zinc, cyanide, borate, phosphate, bile salts, and glycine, in higher concentrations, were inhibitory. Fluoride had no demonstrable effect. Surface-active substances, such as saponin, bile salts, or alkyl sulphate, liberated the enzyme from the cells. Similar results were obtained when α-glycerophosphate or β-glycerophosphate was used as the substrate.The alkaline phosphatase can be considered to belong to Class AI of Folley and Kay (22) and the acid phosphatase to Class AII. The alkaline phosphatase can also be considered to be a Phosphatase II of Cloetens (9).

scholarly journals THE RELATION OF THE THYROID GLAND TO THE SURFACE TENSION OF THE BLOOD PLASMA

1926 ◽  
Vol 43 (2) ◽  
pp. 179-193 ◽  
Author(s):  
C. M. Wilhelmj ◽  
Moyer S. Fleisher
Keyword(s):  
Surface Tension ◽  
Thyroid Gland ◽  
Blood Plasma ◽  
Thyroid Tissue ◽  
Normal Limits ◽  
Minute Period ◽  
Surface Active ◽  
The Difference ◽  
Active Substances ◽  
Accessory Thyroid

1. Following thyroidectomy in guinea pigs, there is a gradual elevation of the surface tension of the blood plasma which reaches its height in from 19 to 22 days after operation. This elevation is probably permanent, since we have found it to persist for as long as 120 days. 2. In our experiments, we found a few thyroidectomized animals in which the surface tension of the plasma was still within normal limits 24 and 120 days after operation. We suggest that these exceptions are due to three possible factors: (1) incomplete thyroidectomy; (2) presence of accessory thyroid tissue; (3) compensatory activity on the part of other organs. 3. The surface tension of the plasma from operated animals is higher than that from controls in both the initial and 20 minute determinations, but the difference is greater at the 20 minute period. 4. The time-drop (difference between the initial and 20 minute determinations) is somewhat greater in the plasma from normal than in that from operated animals. 5. It is suggested that these changes are due to a decrease in the amount of certain normally occurring surface-active substances, the production of which is directly or indirectly dependent upon the thyroid gland.

scholarly journals Droplet activation of moderately surface active organic aerosol predicted with six approaches to surface activity

2021 ◽  
Author(s):  
Sampo Vepsäläinen ◽  
Silvia M. Calderón ◽  
Jussi Malila ◽  
Nønne L. Prisle
Keyword(s):  
Experimental Data ◽  
Surface Tension ◽  
Surface Activity ◽  
Atmospheric Aerosols ◽  
Cloud Microphysics ◽  
Organic Mass ◽  
Surface Partitioning ◽  
Mass Fractions ◽  
Surface Active ◽  
Droplet Activation

Abstract. Surface active compounds (surfactants) found in atmospheric aerosols can decrease droplet surface tension as they adsorb to the droplet surfaces simultaneously depleting the droplet bulk. These processes may influence the activation properties of aerosols into cloud droplets and investigation of their role in cloud microphysics has been ongoing for decades. In this study, we have used six different approaches documented in the literature to represent surface activity in Köhler calculations predicting cloud droplet activation properties for particles consisting of one of three different moderately surface active organics mixed with ammonium sulphate in different ratios. We find that the different models predict comparable activation properties at small organic mass fractions in the dry particles for all three moderately surface active organics tested, even with large differences in the predicted degree of bulk-to-surface partitioning of the surface active component. However, differences between the models regarding both the predicted critical diameter and supersaturation for the same dry particle size increase with the organic fraction in the particles. Comparison with available experimental data shows that assuming complete bulk-to-surface partitioning of the organic component (total depletion of the bulk) along the full droplet growth curve does not adequately represent the activation properties of particles with high moderate surfactant mass fractions. Accounting for the surface tension depression mitigates some of the effect. Models that include the possibility for partial bulk-to-surface partitioning yield comparable results to the experimental data, even at high organic mass fractions in the particles. The study highlights the need for using thermodynamically consistent model frameworks to treat surface activity of atmospheric aerosols and for firm experimental validation of model predictions across a wide range of states relevant to the atmosphere.

scholarly journals Preparation of foaming agents for dust suppression of coal particles

2019 ◽  
pp. 12-18
Author(s):  
Zh.B. Ospanova ◽  
S. Toktagul ◽  
A. Tasmagambetova ◽  
M. Asadov
Keyword(s):  
Surface Tension ◽  
Anionic Surfactants ◽  
Foam Stability ◽  
Sodium Dodecyl ◽  
Solid Particles ◽  
Foaming Agents ◽  
Coal Particles ◽  
Foaming Capacity ◽  
The Stability ◽  
Surface Tension Isotherms

The results of the study of foams stabilized by solid coal particles are given. The method of sedimentation analysis determined the most likely radius of coal particles equal to 20.28 microns. Foaming ability was determined by the height of the foam column obtained by the method of bubbling within 1 min. Foam stability was determined by the time of complete destruction of the foam column. Foams stabilized by the compositions of anionic surfactants – sodium dodecyl sulfate (DDSNa) and sulfonol (SF) with polyvinyl alcohol (PVA) in the presence of hydrophobic solid particles of coal showed greater foaming capacity and stability compared to foams from individual surfactants. The surface tension isotherms of aqueous solutions of surfactants, PVA, and their mixtures were obtained. An increase in the stability of foams in the presence of coal particles corresponds to a decrease in the surface tension at the liquid-gas interface. The stability of foams obtained from surfactant-PVA compositions is explained by the combined influence of thermodynamic (reduction of surface tension) and structural-mechanical (increase in viscosity of inter-membrane fluid) of stability factors. These properties of foams can be used to suppress dust in coal mining.

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.

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