Surface attractive

Recreational surfaces must provide certain performance characteristics with acceptable costs, lifetimes, and appearance. Arbitrary but useful distinctions may be made for classification purposes, depending on the principal function a covering intended primarily to provide an attractive surface for private leisure activities, eg, patio surfaces a surface designed for service in a specific sport, eg, track surfaces or a grass-like surface designed for a broad range of heavy-duty recreational activities, including professional athletics, eg, artificial turf for outdoor sports. 

Light-Duty Recreational Surfaces. Artificial surfaces intended for incidental recreational use, eg, swimming pool decks, patios, and landscaping, are designed primarily to provide a practical, durable, and attractive surface. Minimum cost is a prime consideration and has driven the quaUty of some such products to a low level. Most surfaces in this category utilize polypropylene ribbon and a tufted fabric constmction (see Olefin polymers, polypropylene). ... 

Equilibrium is established when the attractive surface forces are balanced by elastic repulsion forces between the materials. The DMT model states that the elastic repulsion force is related to the attractive force within the contact region Fs by... 

Since the prewetting transition may occur only for weakly attractive surfaces [146], we must choose an appropriate value for the parameter This value has been set as follows e = 3 /3/2 j = 6. This corresponds to a relative strength of the fluid-fluid and fluid-surface potential minima close to that for Ar in contact with sohd carbon dioxide [147]. The second parameter in Eq. (144), zq, was set to 0.8[Pg.219]

Molecular attraction (surface tension, adsorptive, diffusive, and osmotic forces)... 

The sole purpose of the filter support and any applied extracellular matrix is simply to provide a surface for cell attachment and thus to provide mechanical support to the monolayer. However, the filter and matrix also can act as serial barriers to solute movement after diffusion through the cell monolayer. The important variables are the chemical composition of the filter, porosity, pore size, and overall thickness. In some cases, pore tortuosity also can be important. It is desired that the filter, with or without an added matrix, provide a favorable surface to which the cells can attach. However, in some cases these properties can also result in an attractive surface for nonspecific adsorption of the transported solute. In these instances, the appearance of the solute in the receiver compartment of the diffusion cell will not be a true reflection of its movement across the mono-layer. Such problems must be examined on a case-by-case basis. 

In the absence of a load (F = 0) the indentation is zero and the contact radius is also zero. Since no attractive surface forces were considered there is also no adhesion in the Hertz model. 

The adhesion force increases linearly with the particle radius. Surprisingly, it is independent of the elasticity of the materials. This is because of two opposing effects. In a hard material the deformation of the solid is small. As a result the contact area and the total attractive surface energy are small. On the other hand, the repulsive elastic component is small. Both effects compensate each other. Soft materials are strongly deformed. Thus both the attractive surface energy term and the repulsive elastic term are high. 

Polymers. Molecular SIMS is an especially attractive surface analytical technique for the characterization of polymer surfaces because of its high surface sensitivity, molecular specificity over an extended mass range, and versatility in ionization. However, only a few polymer SIMS studies have been reported [104-113] due to the serious sample charging problems that occur with thick insulating films. 

On attractive surfaces (Figure 5.7), the unit (A-—B—C) reaches the barrier or col before the bond B-C has altered much, and starts to move into the exit valley with A... 

Reactions on attractive surfaces with early barriers are promoted by high translational energy in the reactants, with vibrational energy playing a minor role. Selective enhancement by translational energy is easiest when there is a straight run up the entrance valley to the critical configuration. 

Attractive surfaces are normally associated with the forward scattering of stripping reactions, where A approaches BC and from a distance attaches itself to B, and continues on undeflected. 

An endothermic reaction is the exact reverse of the corresponding exothermic reaction. An attractive surface for the exothermic reaction becomes a repulsive... 

The two helical arms become uncoiled in unfolded state a, which is the result of turning off the attractive nonbonding B-B interactions (Cf. Fig. 3). However, the helical structure of the two arms is retained in this unfolded state. The corresponding R distributions are clearly influenced by immobilization, as well as by the type of surface (Cf. Fig. 4). In comparison to the freely diffusing polypeptide, the R distribution in unfolded state a on the attractive surface is seen to be more asymmetrical and shifted to longer values of R. The opposite trend is observed in the case of the repulsive surface, where the distribution becomes more symmetrical and shifts to lower values... 

Fig. 4 Distributions of end-to-end distance, R, under different conditions. Black, red and green correspond to the cases of free diffusion, repulsive surface-immobilization and attractive surface-immobilization, respectively. The results were converged to within an error bar of 5%.

It should also be noted that, for the same value of 7V, T)(TV) in the folded state is smaller than that in the unfolded state. This observation is consistent with the fact that the dynamics in the folded state is in fact faster than that in the unfolded state. It should also be noted that the values of D(Tw) in the folded and unfolded states are rather similar in the case of the attractive surface. This is due to the above mentioned rapid dynamics of the unfolded polypeptide relative to the attractive surface. 

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