scholarly journals Physical Theory of Fluid Interfaces Near the Critical Point

1972 ◽  
Vol 25 (4) ◽  
pp. 367 ◽  
Author(s):  
KW Sarkies ◽  
P Richmond ◽  
BW Ninham
Keyword(s):  
Free Energy ◽  
Critical Point ◽  
Physical Theory ◽  
Scaling Laws ◽  
Continuum Theory ◽  
The Self ◽  
Fluid Interfaces ◽  
Fluid Interface ◽  
Simple Fluids ◽  
Energy Of Interaction

A continuum theory of surfaces is developed for fluids near their critical points. The free energy of the fluid interface is considered to consist of two terms: the self free energy of inhomogeneity and an energy of interaction across the interface due to van der Waals forces. This second term is computed via the principles of Lifshitz theory and gives a physical basis to Widom's modification of the Cahn?Hilliard theory of surfaces. The scaling laws as derived by Widom are recalculated, and several differences from the original laws emerge. The theory permits calculation of absolute values of surface tensions and interface widths near the critical point from experimental dielectric and free energy data. Furthermore, the fluids considered are not necessarily simple fluids where only pairwise forces are important.

scholarly journals Self-diffusiophoresis induced by fluid interfaces

Soft Matter ◽  
2018 ◽  
Vol 14 (8) ◽  
pp. 1375-1388 ◽  
Author(s):  
P. Malgaretti ◽  
M. N. Popescu ◽  
S. Dietrich
Keyword(s):  
Physical Properties ◽  
The Self ◽  
Fluid Interfaces ◽  
Axially Symmetric ◽  
Fluid Interface ◽  
Two Fluid ◽  
Fluid Phases

The influence of a fluid–fluid interface on the self-phoresis of chemically active spherical colloids is analyzed for axially symmetric configurations. Distinct from the case of hard walls, motion of the particle either towards or away from the interface can be induced by tuning the physical properties of one of the two fluid phases.

scholarly journals Use of scaled-particle theory in the assessment of the Ph4As+/Ph4B− assumption for single ions

1979 ◽  
Vol 57 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Michael H. Abraham ◽  
Asadollah Nasehzadeh
Keyword(s):  
Free Energy ◽  
Recent Work ◽  
Scaled Particle Theory ◽  
Cavity Formation ◽  
Energy Term ◽  
Free Energies ◽  
Particle Theory ◽  
Novel Method ◽  
Energy Of Interaction ◽  
Solvent Molecules

A novel method for the assessment of the Ph4As+/Ph4B− assumption for free energies of transfer of single ions has recently been suggested by Treiner, and used by him to deduce that the assumption is not valid for transfers between water, propylene carbonate, sulpholane, dimethylsulphoxide, N-methyl-2-pyrrolidone, and perhaps also dimethylformamide. The basis of the method is the estimation of the free energy of cavity formation by scaled-particle theory, together with the hypothesis that the free energy of interaction of Ph4As+ (or Ph4B−) with solvent molecules is the same in all solvents, ΔGt0(int) = 0. It is shown in the present paper that (a) whether or not the Ph4As+/Ph4B− assumption applies to transfer to a given solvent depends on which other solvent is taken as the reference solvent in Treiner's method, (b) the calculation of the cavity free energy term by scaled-particle theory and by the theory of Sinanoglu – Reisse – Moura Ramos (SRMR) yields values so different that the method cannot be considered reliable, (c) the calculation of cavity enthalpies and entropies for Ph4As+ or Ph4B− by scaled-particle theory yields results that are chemically not reasonable, (d) the hypothesis that ΔGt0(int) = 0 conflicts with SRMR theory, and (e) the conclusions reached by Treiner are not in accord with recent work that in general supports the Ph4As+/Ph4B− assumption for solvents that are rejected by Treiner.

scholarly journals THE CRITICAL POINT OF UNORIENTED RANDOM SURFACES WITH A NONEVEN POTENTIAL

1993 ◽  
Vol 08 (06) ◽  
pp. 1139-1152
Author(s):  
M.A. MARTÍN-DELGADO
Keyword(s):  
Free Energy ◽  
Partition Function ◽  
Critical Point ◽  
Discrete Model ◽  
Recursion Relation ◽  
Scaling Limit ◽  
Random Surfaces ◽  
Matrix Ensemble ◽  
Quartic Interaction ◽  
Double Scaling Limit

The discrete model of the real symmetric one-matrix ensemble is analyzed with a cubic interaction. The partition function is found to satisfy a recursion relation that solves the model. The double scaling-limit of the recursion relation leads to a Miura transformation relating the contributions to the free energy coming from oriented and unoriented random surfaces. This transformation is the same kind as found with a quartic interaction.

scholarly journals In situ assessment of the contact angles of nanoparticles adsorbed at fluid interfaces by multiple angle of incidence ellipsometry

Soft Matter ◽  
2014 ◽  
Vol 10 (36) ◽  
pp. 6999-7007 ◽  
Author(s):  
Antonio Stocco ◽  
Ge Su ◽  
Maurizio Nobili ◽  
Martin In ◽  
Dayang Wang
Keyword(s):  
Surface Coverage ◽  
Contact Angles ◽  
Fluid Interfaces ◽  
Angle Of Incidence ◽  
Fluid Interface ◽  
Colloidal Interactions ◽  
In Situ Assessment

Contact angles and surface coverage of nanoparticles adsorbing at the fluid interface are assessed by ellipsometry. Results reveal the competition between wetting and colloidal interactions.

scholarly journals Thermodynamics, maximum power, and the dynamics of preferential river flow structures on continents

2012 ◽  
Vol 9 (6) ◽  
pp. 7317-7378 ◽  
Author(s):  
A. Kleidon ◽  
E. Zehe ◽  
U. Ehret ◽  
U. Scherer
Keyword(s):  
Free Energy ◽  
Large Scale ◽  
Scaling Laws ◽  
Preferential Flow ◽  
River Flow ◽  
Thermodynamic Description ◽  
Minimum Energy ◽  
Flow Structures ◽  
Drainage Basins ◽  
Drainage Systems

Abstract. The organization of drainage basins shows some reproducible phenomena, as exemplified by self-similar fractal river network structures and typical scaling laws, and these have been related to energetic optimization principles, such as minimization of stream power, minimum energy expenditure or maximum "access". Here we describe the organization and dynamics of drainage systems using thermodynamics, focusing on the generation, dissipation and transfer of free energy associated with river flow and sediment transport. We argue that the organization of drainage basins reflects the fundamental tendency of natural systems to deplete driving gradients as fast as possible through the maximization of free energy generation, thereby accelerating the dynamics of the system. This effectively results in the maximization of sediment export to deplete topographic gradients as fast as possible and potentially involves large-scale feedbacks to continental uplift. We illustrate this thermodynamic description with a set of three highly simplified models related to water and sediment flow and describe the mechanisms and feedbacks involved in the evolution and dynamics of the associated structures. We close by discussing how this thermodynamic perspective is consistent with previous approaches and the implications that such a thermodynamic description has for the understanding and prediction of sub-grid scale organization of drainage systems and preferential flow structures in general.

Note on magneto-hydrodynamic gravitational stability of a double fluids interface

2008 ◽  
Vol 86 (3) ◽  
pp. 477-485
Author(s):  
Ahmed E Radwan ◽  
Mourad F Dimian
Keyword(s):  
Dispersion Relation ◽  
Present Model ◽  
The Self ◽  
Wave Number ◽  
Symmetric Mode ◽  
Fluid Interface ◽  
Unperturbed State ◽  
Gravitational Stability ◽  
The Stability ◽  
Range Force

The magneto–gravitational stability of double-fluid interface is discussed. The pressure in the unperturbed state is not constant because the self-gravitating force is a long-range force. The dispersion relation is derived and discussed. The self-gravitating model is unstable in the symmetric mode m = 0 (m is the transverse wave number), while it is stable in all other states. The effects of the densities, the liquid-fluid radii ratios, and the electromagnetic force on the stability of the present model are identified for all wavelengths.PACS Nos.: 47.35.Tv, 47.65.–d, 04.40.–b

Free Energy of Granular Materials in Static Equilibrium

1979 ◽  
Vol 46 (4) ◽  
pp. 944-945 ◽  
Author(s):  
M. Shahinpoor ◽  
G. Ahmadi
Keyword(s):  
Free Energy ◽  
Granular Materials ◽  
Continuum Theory ◽  
Gravitational Effect ◽  
Experimental Results ◽  
Static Equilibrium ◽  
The Continuum

We employ the continuum theory of granular materials due to Goodman and Cowin and some experimental results due to P. G. Nutting to arrive at a functional from for the free energy of granular materials in static equilibrium. The results obtained indicate the dominance of gravitational effect, modify and enlarge the results previously obtained by J. T. Jenkins.

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