Snowpack-stored atmospheric surface-active contaminants traced with snowmelt water surface film rheology

Abstract The aim of the study was to quantify the adsorptive and thermo-elastic properties of snowmelt water surface films and their spatial-temporal evolution with snowpack structure characteristics and the entrapped surface-active organic composition. Surface pressure–area (π-A)T isotherms, surface pressure-temperature (π-T)A isochors, and stress–relaxation (π-t) measurements were performed using a Langmuir trough system on snowmelt water samples collected in a large-scale field studies performed at several industrialized and rural Tricity (Gdansk, Poland) areas at various environmental conditions and subsequent stages of the snowpack melting progress. Since the snow-melted water composition and concentrations of surface active organic matter fractions therein are largely undetermined, the force-area isotherm scaling formalisms (2D virial equation and 2D film scaling theory of polymeric films) were adapted to the complex mixture of surfactants. The surface film parameters and their spatial and temporal evolution turned out to be unequivocally related to principal signatures of the film-forming materials: surfactant concentrations (π, Alim), surface activity (Eisoth, |E|), film material solubility (R), surface material miscibility and 2D architecture complexity (y, βs), molecular thermal mobility (πk), and a timescale of the relaxation processes within the film (τi, |E|). Moreover, the parameters appeared to be correlated with snowpack structure characteristics (snow density ρ, specific snow area SSA, snow cover thickness), sample age time, and anthropogenic atmospheric contamination pressure source locations. In particular, Eisoth was found to be related to ρ and SSA, while R correlated with the solubility of film-forming organics which turned out to be long-chain fatty acids; similarly, spatial profiles of Eisoth revealed the peak values next to the areas being under a severe anthropogenic air pollution pressure. Snowmelt water films stand for a structurally heterogeneous (y > 10) interfacial system where several transition processes of differentiated time-scales (relaxation times from 7 to 63 s) took place leading to the apparent surface viscoelasticity. To sum up, the established surface rheological parameters could serve as novel indicators, based solely on physical attributes, allowing to follow the snowpack evolution, and its melting polymorphism in order to test or improve the existing snow-entrapped organics release models based on chemical analyses. The cross-correlation functional dependences of practical value remain to be established on the larger data set.

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Film forming behaviour of oil soluble polyalkylene glycols

Industrial Lubrication and Tribology ◽

10.1108/ilt-01-2013-0014 ◽

2015 ◽

Vol 67 (2) ◽

pp. 133-138 ◽

Cited By ~ 4

Author(s):

Martin Greaves ◽

Ksenija Topolovec Miklozic

Keyword(s):

Contact Pressure ◽

Film Formation ◽

Surface Film ◽

Electrical Contact ◽

Electrical Contact Resistance ◽

Content Type ◽

Film Forming ◽

Specific Contact ◽

Surface Active ◽

Forming Behaviour

Purpose – The purpose of this paper was to examine the film-forming behaviour of simple compositions of polyalphaolefin (PAO) containing an oil-soluble polyalkylene glycol (OSP) alone, a zinc dialkyl dithiophosphate (ZDDP) alone and then combinations of an OSP and ZDDP. Design/methodology/approach – A Mini-Traction Machine with Spacer Layer Imaging technology was used to evaluate friction and film formation under a specific contact pressure, temperature and slide-to-roll ratio. Electrical contact resistance measurements were used to follow surface film formation. Findings – The inclusion of an OSP to a PAO showed evidence of friction-reducing behaviour with low friction values over the rubbing cycle but no significant tribo-film build up. When a ZDDP (1 per cent) is added to the PAO, a thick tribo-film forms of about 100 nm. Addition of an OSP (10 per cent) shows this film still forms despite the OSP being a polar and surface-active additive. Research limitations/implications – The study was conducted under a narrow range of test conditions (e.g. temperature and contact pressure), and future work will focus on friction and film formation across a broader set of conditions. Practical implications – Despite OSPs being polar and surface-active, they do not interfere with the ZDDP in forming an anti-wear film in a PAO and, therefore, their inherent properties of good deposit control could enhance the performance of modern lubricants. Originality/value – OSPs offer promising benefits as friction reducers in PAOs. The research also suggests that OSPs do not negate the formation of ZDDP anti-wear tribo-films when in combination in a PAO.

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Confinement And Control Of Oil Pollution On Water With Monomolecular Surface Films

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-1969-1-257 ◽

1969 ◽

Vol 1969 (1) ◽

pp. 257-261 ◽

Cited By ~ 4

Author(s):

William D. Garrett

Keyword(s):

Water Surface ◽

Oil Pollution ◽

Surface Film ◽

Thick Layer ◽

Surface Films ◽

Film Material ◽

Chemical Character ◽

Favorable Conditions ◽

And Control ◽

Reduced Surface

Abstract Under favorable conditions monomolecular surface films can be used to guide, confine and condense petroleum spills on water. Composed of water-insoluable, non-toxic organic material, these films spread rapidly and spontaneously into a one-molecule-thick layer. Consequently, small quantities of piston-film material will clear thin oil layers from large areas of a water surface. The effects of wind, the chemical character of the pollution and its thickness upon the usefulness of the piston film will be discussed. In addition to clearing water surfaces of oil, one of the most useful applications may be the ability of the surface film to confine and condense a small oil spill into layers as thick as one centimeter. Since the petroleum is thickened and compressed into a much reduced surface area, the efficiency of oil retrieval techniques would be enhanced.

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Role of surface films in the germination of rust uredospores

Canadian Journal of Botany ◽

10.1139/b70-071 ◽

1970 ◽

Vol 48 (3) ◽

pp. 499-511 ◽

Cited By ~ 6

Author(s):

William Woodbury ◽

Mark A. Stahmann

Keyword(s):

Surface Area ◽

Water Surface ◽

Surface Film ◽

Storage Conditions ◽

Surface Films ◽

Film Material ◽

Humid Atmosphere ◽

Infection Structures ◽

Film Area

An association of rust uredospores with materials which form films on water surfaces was demonstrated. One milligram of spores of Puccinia graminis tritici and 3.5 mg of Uromyces phaseoli spores released about 100 cm2 of film within 1 min of coming into contact with a large water surface. Oxidative reactions within these films, which were accelerated by light, formed products which inhibited spore germination. When spores were germinated on a large volume of water, germination varied with the surface area, which indicated that inhibitor was formed and retained at the water surface.Hydration of spores resulted in an increased germination, a decreased film area and a delay or prevention of film reactions. Storage of spores at lower humidities resulted in decreased germination, decreased film area, and film reactions which began as soon as the spores came into contact with the water surface. These results suggest that the effects of light and of storage conditions on germination may be mediated by surface film materials.The amount of surface film material released by wheat and bean rust spores may be correlated with the wetability of the host cuticle and also with the ability of rusts to differentiate infection structures in vitro on artificial membranes. On plastics which supported the formation of infection structures, spores acquired spherical infection droplets when exposed to a humid atmosphere. The surface area of these droplets was correlated with the area of surface film. It is suggested that surface film material may interact with the appropriate host cuticle to determine the size and configuration of infection droplets. This would provide a water surface of defined area upon which film reactions occur resulting in a sequence of products which control germination, directed growth of the germ tube and differentiation of infection structures.

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On the Use of Monolayers to Reduce Evaporation From Stationary Water Pools

Journal of Heat Transfer ◽

10.1115/1.2910650 ◽

1993 ◽

Vol 115 (1) ◽

pp. 209-214 ◽

Cited By ~ 9

Author(s):

T. D. Tang ◽

M. T. Pauken ◽

S. M. Jeter ◽

S. I. Abdel-Khalik

Keyword(s):

Experimental Investigation ◽

Relative Humidity ◽

Water Surface ◽

Surface Film ◽

Free Water ◽

Vapor Concentration ◽

Controlled Environment ◽

Stearyl Alcohol ◽

Water Pool ◽

Evaporation Suppression

An experimental investigation has been conducted to quantify the extent by which monolayers of fatty alcohols can reduce evaporation from a deep stationary water pool within a controlled environment. Octadecanol (stearyl alcohol), C17H35–CH2–OH, was chosen as the surface film and ethanol was selected to be the spreading agent. Evaporation suppression of 60 percent was achieved at a water temperature of 25°C with an air temperature of 20°C and a relative humidity of 70 percent. The experimental techniques and data have been validated by comparing the measured evaporation rates for film-free water with earlier data published by other investigators. Data for the evaporation rates of water covered by octadecanol films were correlated as a function of vapor concentration differences between the water surface and air.

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BOREAS TF-11 SSA FEN 1996 WATER SURFACE FILM CAPPING DATA

ORNL Distributed Active Archive Center Datasets ◽

10.3334/ornldaac/455 ◽

1999 ◽

Author(s):

D. P. BILLESBACH ◽

S. B. VERMA

Keyword(s):

Water Surface ◽

Surface Film

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Surfactant convertase action is not essential for surfactant film formation

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1997.273.5.l907 ◽

1997 ◽

Vol 273 (5) ◽

pp. L907-L912 ◽

Cited By ~ 4

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.

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INTERACTION OF NANOSTRUCTURED LIPID CARRIERS WITH HUMAN MEIBUM

International Journal of Applied Pharmaceutics ◽

10.22159/ijap.2019v11i3.29158 ◽

2019 ◽

pp. 35-42

Author(s):

Pattravee Niamprem ◽

Thomas J. Milla ◽

Burkhardt S. Schuett ◽

S. P. Srinivas ◽

Waree Tiyaboonchai

Keyword(s):

Particle Size ◽

Surface Pressure ◽

Tear Film ◽

Nanostructured Lipid Carriers ◽

Langmuir Trough ◽

Surface Activities ◽

Lipid Films ◽

Pressure Area ◽

Surface Active ◽

High Pressure Homogenizer

Objective: This study aimed to determine the possibility of nanostructured lipid carriers (NLCs) as a bionic tear film by determining the surface activities of the developed NLCs and their interaction with human meibomian lipid films. Methods: NLCs with different types of solid lipids and surfactants were prepared by a high-pressure homogenizer. The particle size was determined by dynamic light scattering. The surface activities of the NLCs and NLCs mixed with meibomian lipids were measured using a Langmuir trough and the resulting surface pressure area (Π-A) profiles were compared. These lipid films were further analyzed using fluorescence microscopy and scanning electron microscopy (SEM). Results: The particle size of prepared NLCs varied from 38–280 nm based on types of solid lipid and surfactant. All NLCs were highly surface active as indicated by their maximum surface pressure (Πmax). The Π-A profiles of meibum seeded with NLCs showed higher surface pressure than meibum alone and the shape of profiles were dominated by the meibomian lipids. These findings were in agreement with fluorescence and SEM micrographs, which revealed that the NLCs could adsorb and integrate to the meibomian lipid films as well as diffuse from the subphase to the lipid films. Conclusion: NLCs are surface active and can integrate with meibomian lipid films formed stable films. The type of interaction can be tailored by altering the solid lipids used in the formulation of the NLCs which could provide the means to develop efficient formulations for targeting dry eye disease related to a non-functional tear film lipid layer.

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Study of Electric Field-Induced Evaporation Like Process and Nucleation in Nanoscale

Journal of Heat Transfer ◽

10.1115/1.4043301 ◽

2019 ◽

Vol 141 (6) ◽

Author(s):

M. B. Darshan ◽

Pratyush Agarwal ◽

Dhiraj Indana ◽

Saikat Datta ◽

Ravi Kumar ◽

...

Keyword(s):

Electric Field ◽

Water Surface ◽

Temporal Evolution ◽

Temperature Fluctuations ◽

High Heat ◽

Density Variation ◽

Nonuniform Electric Field ◽

Uniform Electric Field ◽

Water Molecules ◽

Dynamics Simulations

A proposal is made to demonstrate features of thermodynamic evaporation at the nanoscale using only an external electric field. The consequences of exposure to both uniform and nonuniform electric field on the water nanofilms are analyzed through molecular dynamics simulations. The temporal evolution of temperature and molecular nucleation under uniform electric field resembles evaporation at high heat. The temperature fluctuations of the system are analyzed from the density variation of the system, which has received no heat input from outside. Evaporation like process and nucleation from the water surface is described as a systematic polarization of the water molecules in the presence of electric field. The nucleation of the vapor bubble with a nonuniform electric field also shows similarity with heat-induced pool boiling. The reason behind isolated nucleation is analyzed from the temperature map of the system at different time instants. Possible surface instabilities due to the exposure of electric field on water nanolayer are also elaborated for both uniform and nonuniform cases.

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