Liquids, interactive

Molecular mechanics methods have been used particularly for simulating surface-liquid interactions. Molecular mechanics calculations are called effective potential function calculations in the solid-state literature. Monte Carlo methods are useful for determining what orientation the solvent will take near a surface. Molecular dynamics can be used to model surface reactions and adsorption if the force held is parameterized correctly. 

Good-GLrifalco-Fowkes (GGF) equation Using ysi = ysv + yiv - 20(ysvyiv) in Young s equation leads to 1+COS0 2 Uvj Yggf obtained from a plot COS0 versus 4> is solid-liquid interaction parameter 0 = 1 if the interactions are purely dispersive. Based on Berthelot relation for attractive constants valid only when the solid-liquid interactions are dominantly dispersive. [77-82]... 

In general, most of the methods used to analyze the chemical nature of the ionic liquid itself, as described in Chapter 4, should also be applicable, in some more sophisticated form, to study the nature of a catalyst dissolved in the ionic liquid. For attempts to apply spectroscopic methods to the analysis of active catalysts in ionic liquids, however, it is important to consider three aspects a) as with catalysis in conventional media, the lifetime of the catalytically active species will be very short, making it difficult to observe, b) in a realistic catalytic scenario the concentration of the catalyst in the ionic liquid will be very low, and c) the presence and concentration of the substrate will influence the catalyst/ionic liquid interaction. These three concerns alone clearly show that an ionic liquid/substrate/catalyst system is quite complex and may be not easy to study by spectroscopic methods. 

Substitution of fluoride ions by other suitable ions in the complex acid so as to separate the fluorine ions from tantalum and niobium (liquid-liquid interaction) ... 

Rubber swelling modifies the liquid/solid work of adhesion. Wo, because in addition to the initial liquid/solid interactions, liquid diffusion into the solid produces supplementary liquid/liquid interactions, hquid molecules having passed through the liquid/solid interface. Therefore, to the initial work of adhesion in the absence of swelling, Wq, an additional term corresponding to a fraction of the cohesion energy of the liquid, 2y, should be added. If / is the time of diffusion, the work of adhesion at /, Wo(t), can then be expressed as... 

It has been shown that the kinetics of the spreading of a liquid on a rubber is largely dependent on viscoelastic dissipation in the wetting ridge of the substrate near the triple line. This behavior may, in practice, be slightly altered by moderate swelling that modifies the solid/liquid interactions for long contact times. 

The liquid mean residence time, tm, in counter-current mode was significantly lower than in co-current mode. Statistical analysis (Yates method of ANOVA) indicates that along with the liquid flowrate, the direction of liquid travel is the most significant factor in the liquid mean residence time. This variation in the liquid phase mean residence time, suggests an increase in short-circuiting or channeling in the counter-current mode as a result of the gas-liquid interactions. 

A.F.M. Barton, Handbook of Polymer-Liquid Interaction Parameters and Solubility Parameters, CRC Press, Boca Raton, FL (1990). 

Both adsorptive and capillary forces play an important part in soil-liquid interaction (see Figure 18.3). This is very important for unsaturated soil. The total force (i.e., the sum of capillary force and adsorptive force) is termed the matrix potential, which has a negative gage pressure relative to the external gas pressure on the soil water (more often the gage pressure is referred to as the atmospheric pressure). 

Truong D.N. FRancois J. in Solid-Liquid Interactions in Porous Media. Ed.Technip, Paris, 1982, p.251... 

Ionic liquids interact very efficiently with microwaves through the ionic conduction mechanism (see Section 2.2) and are rapidly heated at rates easily exceeding 10 °C s"1 without any significant pressure build-up [52]. Therefore, safety problems arising from over-pressurization of heated sealed reaction vessels are minimized. 

The starting point for the calculation of g(r) is the Ornstein-Zernike (OZ) equation, which, for a one-component system of liquids interacting via spherically symmetric potentials (e.g. Argon), is [89]... 

The first MC (16) and MD (17) studies were used to simulate the properties of single particle fluids. Although the basic MC (11,12) and MD (12,13) methods have changed little since the earliest simulations, the systems simulated have continually increased in complexity. The ability to simulate complex interfacial systems has resulted partly from improvements in simulation algorithms (15,18) or in the interaction potentials used to model solid surfaces (19). The major reason, however, for this ability has resulted from the increasing sophistication of the interaction potentials used to model liquid-liquid interactions. These advances have involved the use of the following potentials Lennard-Jones 12-6 (20), Rowlinson (21), BNS... 

Up until this point, we have been considering only surface-liquid interactions where the solid is purely rigid and is perfectly secured to some lower surface upon which it rests. This is usually a good approximation however, in some... 

Mirabel, P., George, C., Magi, E., and Ponche, J.E. Gas-liquid interactions, in Heterogeneous and Liquid-Phase Processes, Warneck, P., Ed. (Berlin Springer-Verlag, 1996), pp. 175-181. 

Their expression for a liquid interaction parameter (L) follows Mott (1968) and starts with the simple sum of an attractive term, Co, and a repulsive term, Cp,... 

The ultimate aim of scientists has always been to be able to see molecules while active. In order to achieve this goal, the microscope should be able to operate under ambient conditions. Further, all kinds of molecular interactions between a solid and its environment (gas or liquid or solid), initially, can take place only via the surface molecules of the interface. It is obvious that, when a solid or liquid interacts with another phase, knowledge of the molecular structures at these interfaces is of interest. The term surface is generally used in the context of gas-liquid or gas-solid phase boundaries, while the term interface is used for liquid-liquid or liquid-solid phases. Furthermore, many fundamental properties of surfaces are characterized by morphology scales of the order of 1 to 20 nm (1 nm = 10-9 m = 10 A (Angstrom = 10-8 cm). 

Solvent-polymer compatibility problems are often encountered in industry, such as in the selection of gaskets or hoses for the transportation of solvents. A rough guide exists to aid the selection of solvents for a polymer, or to assess the extent of polymer-liquid interactions. A semi empirical approach has been developed by Hildebrand based on the principle of like dissolves like. The treatment involves relating the enthalpy of mixing to a solubility parameter, S, and its related quantity, 8, called the cohesive energy density. 

Some components in a gas or liquid interact with sites, termed adsorption sites, on a solid surface by virtue of van der Waals forces, electrostatic interactions, or chemical binding forces. The interaction may be selective to specific components in the fluids, depending on the characteristics of both the solid and the components, and thus the specific components are concentrated on the solid surface. It is assumed that adsorbates are reversibly adsorbed at adsorption sites with homogeneous adsorption energy, and that adsorption is under equilibrium at the fluid- adsorbent interface. Let (m" ) be the number of adsorption sites and (m 2) the number of molecules of A adsorbed at equilibrium, both per unit surface area of the adsorbent. Then, the rate of adsorption r (kmol m s ) should be proportional to the concentration of adsorbate A in the fluid phase and the number of unoccupied adsorption sites. Moreover, the rate of desorption should be proportional to the number of occupied sites per unit surface area. Here, we need not consider the effects of mass transfer, as we are discussing equilibrium conditions at the interface. At equilibrium, these two rates should balance. Thus,... 

Fowkes, F. M., F. L. Riddle Jr., W. E. Pastore, and A. E. Weber, Interfacial interactions between self-associated polar liquids and squalane used to test equations for solid-liquid interactions , Colloids and Surfaces, 43, 367-387 (1990). 

The spectra of liquids and solids are known to have strong induced components. Liquids and solids are, however, so dense that many-body terms dominate the spectra the binary and ternary spectral components which are the main topic of this work (and which are usually measurable in compressed gases at densities much lower than liquid state) will often resemble the spectra of liquids and solids, but a critical comparison will reveal important qualitative and quantitative differences. Nevertheless, a study of binary spectra will help to illuminate important aspects of the theoretical descriptions of liquid spectra and may be considered a basic input into the theory of liquid interactions with radiation. 

Figure 19.12. Batch parametric processing of solid-liquid interactions such as adsorption or ion exchange. The bottom reservoir and the bed interstices are filled with the initial concentration before pumping is started, (a) Arrangement of adsorbent bed and upper and lower reservoirs for batch separation, (b) Synchronization of temperature levels and directions of flow (positive upward), (c) Experimental separation of a toluene and n-hcptane liquid mixture with silica gel adsorbent using a batch parametric pump. (Reprinted from Wilhelm, 1968, with permission of the American Chemical Society), (d) Effect of cycle time t on reservoir concentrations of a closed system for an NaCl-H20 solution with an ion retardation resin adsorbent. The column is initially at equilibrium with 0.05M NaCl at 25°C and a = 0.8. The system operates at 5° and 55°C. [Sweed and Gregory, AIChE J. 17, 171 (1971)J.

The parachor does not have a readily apparent physicochemical meaning it is useful as a parameter for estimating a range of other properties, especially those related to liquid-liquid interactions. 

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