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Showing 1 to 20 of 20 for “"disjoining pressure"”.
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Pore-scale Interfacial and Transport Phenomena in Hydrocarbon Reservoirs
… width down to 2nm occurs at a critical invasion pressure similar to that predicted by the classical capillary theories if effects of disjoining pressure and diffusiveness of water-gas interfaces are considered. The invasion of oil droplets into water-filled pores can face a free energy barrier if …
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A study of bubble wetting on surfaces
… two key areas for improvement are identified: disjoining pressure effects and gravitationaleffects. Wetting of textured surfaces is also analyzed for bubble application, leading to a prediction that a model based on a Cassie-Baxter analysis with knowledge of bubble wetting on a flat surface …
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Studies of Bitumen Aeration
… information that can be used to determine the disjoining pressures (∏) in the wetting films. The results obtained in the present work show that ∏ < 0 for maltene and bitumen, while ∏ > 0 for asphaltene at temperatures in the range of 22 to 80 °C. The disjoining pressure data have been analyzed …
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Thermal Management Using Liquid-vapor Phase Change in Nanochannels
… part of the dissertation is related to the disjoining pressure driven flow of nanoscale liquid film and liquid-vapor phase change in nano confinement. First, experimental and numerical investigation of droplet wicking in ∼728 nm height cross-connected buried SiO2 nanochannels, with …
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Hydrophobic Forces in Wetting Films
… force for film thinning was the sum of capillary pressure and the disjoining pressure in a thin film. It was found that the kinetics curves obtained with hydrophilic surfaces can be fitted to the theory with the disjoining pressure calculated from the DLVO theory. With hydrophobized surfaces, …
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Surface Forces in Foam Films
… and froths in froth flotation. The thin film pressure balance (TFPB) technique was used to study the surface forces between air bubbles in water from equilibrium film thickness and dynamic film thinning measurements. The results were compared with the disjoining pressure predicted from the …
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Modeling Bubble Coarsening in Froth Phase from First Principles
… the TLFs thin initially due to the capillary pressure created by curvature changes. As the film thicknesses (H) reach approximately 200 nm, the disjoining pressure created by surface forces in the films also begins to control the film drainage rate and affect the waves motions at the air/water …
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Flotation of sulfide minerals with alkyl pyridinium salts
… minimizes the electrostatic component of the disjoining pressure of the wetting film. CpCl has also demonstrated a remarkable selectivity despite the fact that both chalcopyrite and the silicious gangue minerals present in the ore are negatively charged. This may be explained by the premise …
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Hydrophobic Forces in Free Thin Films of Water in the Presence and Absence of Surfactants
… with increasing surfactant concentration.. The disjoining pressure isotherm for both surfactant systems in the presence of inorganic electrolyte (NaCl) were also obtained. The results indicated that the K232 values estimated from the equilibrium film thickness measurements can be used to fit the …
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Applications and Methods for Increased Liberation and Separation in the Deinking of Recycled Paper Fiber
… increases the liberation by increasing the disjoining pressure in the thin liquid film (TLF) of water confined between the pigment and fiber while at the same time preventing re-deposition. After the liberation, the pigments are then hydrophobized by adsorbing a surfactant on the surface to …
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Microfluidic Study of Gravity-Driven Drainage and Coalescence of Aqueous Two Dimensional Foams
… phase, which is caused by the difference in pressures between the bubbles and droplets due to their size differences. This causes the smaller bubbles to disappear and the larger bubbles to grow (Oswald ripening or coarsening). Coalescence can be significantly retarded by the use of …
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Development and Validation of a Simulator based on a First-Principle Flotation Model
… that bubble-particle attachment occurs when the disjoining pressure of the thin liquid in a wetting films formed between particle and bubble is negative, as was first suggested by Laskowski and Kitchener (1969). These provisions allow for the flotation model to incorporate various chemistry …
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Instabilities in newtonian films and nematic liquid crystal droplets
… partially wetting fluids by introducing the disjoining pressure in the thin film equation. It is found that there exists an additional regime where the film breaks up into a series of droplets. For nematic liquid crystal droplets, a model is derived based on the long wave approach available …
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Expansion and shrinkage of early age cementitious materials under saturated conditions : the role of colloidal eigenstresses
… origin under controlled temperature and pressure conditions. To achieve this goal, an original set of macroscopic scale experiments is designed and a multiscale microporomechanics model is employed to rationalize the experimental results. While bulk volume changes have been classically …
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The numerical simulation of thin film flow over heterogeneous substrates
… which occurs there is alleviated by means of a disjoining pressure model. The latter allows prescription of a local equilibrium contact angle and three dimensional numerical simulations reveal how droplets can be forced to either wet or dewet a region containing topography depending on the …
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Instabilities of volatile films and drops
… Marangoni effect, vapor recoil, disjoining pressure, and gravity. The crucial ingredient in this problem is the evaporation model, since it influences both the motion of the drop contact line, and the temperature profiles along the liquid-solid and liquid-gas interfaces. We …
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Modeling Flotation from First Principles Using the Hydrophobic Force as a Kinetic Parameter
… hydrophobic air bubbles. A TLF ruptures when the disjoining pressure (or surface forces per unit area) of the film becomes negative, i.e., Π < 0. Thermodynamically, a wetting film can rupture when the contact angle (θ) of a mineral surface is larger than zero. It would, therefore, be reasonable to …
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Effect of Non-Ionic Surfactants and Nano-Particles on the Stability of Foams
The thin film pressure balance (TFPB) technique were used to study the stability of single foam films produced in the presence of n-alkyl polyoxyethylene (CnEOm) homologues. The results showed that films thin faster than predicted by the classical DLVO theory, which considers contributions from the …
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Experimental and Modelign of Foam Physics in Porous Media
… certain critical thickness at which the maximum disjoining pressure is attained. This mechanism is incorporated in the pore network model to which we add a notional time-dependency of the invasion percolation with memory mechanism. After the onset of foam mobilization, the drag on moving lamellae …
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Thin liquid films with nanoparticles and rod-like ions as models for nanofluidics
… that this is an ion bridging component of the disjoining pressure. The results show that for films prepared in presence of spermidine the transformation of the thicker CF to the thinnest NBF is more probable as films prepared with NaCl at similar conditions of electrostatic interaction. This …