Rigid substrate

PVDF film is readily commercially available in thicknesses up to 110 pm. If film of this thickness is bonded to a rigid substrate, the peak response is at a frequency of about 3.7 MHz which corresponds to the thickness of the layer being a quarter wavelength. This frequency is rather high for most Lamb wave testing since Fig 1 shows that even on a I mm thick... 

Typically specimens for reflectivity measurements are prepared on flat, smooth, rigid substrates. For example, these substrates can be polished fused silica, quartz, or silicon. It is important, however, that the substrates be thick to avoid distonions of the specimen when mounted in the reflectometer. Any curvature or bowing will increase the divergence of the incident beam and result in a deterioration of the resolution. 

For the compliant sphere against a rigid substrate, the contact area is a flat circle of radius a so that... 

As previously discussed, the JKR theory predicts that the detachment force is independent of the Young s modulus. Yet despite that, when Gady et al. [117] measured the detachment force of polystyrene particles from two elastomeric substrates having Young s moduli of 3.8 and 320 MPa, respectively, they found that the detachment force from only the more compliant substrate agreed with the predicted value. The force needed to separate the particle from the more rigid substrate was about a factor of 20 lower. Estimates of the penetration depth revealed that the particles would penetrate into the more compliant substrate more deeply than the heights of the asperities. Thus, in that case, the spherical particle approximation would be reasonable. On the other hand, the penetration depth... 

The applications of rubber as an engineering material almost invariably involve bonding to a rigid substrate or reinforcement. In some instances these bonds need to be established to a fully cured thermoset rubber or a molded thermoplastic rubber, and a wide variety of adhesives suitable for this purpose are available. In... 

The process of viscoelastic braking just described has certain parallels with the dynamic adhesion of elastomers. When, for example, a rubber strip is peeled from a rigid substrate, the effective, or apparent, work of adhesion, W, is usually much greater than the intrinsic, or reversible, energy of adhesion, Wq, given by the Dupre equation [15] ... 

However, on rigid substrates, the growth of dry zones is accompanied by a rim of excess liquid with width X (Fig. 10). As the dewetting proceeds, X increases. For short times and < K, the growth of dry patches is controlled only by surface tension forces and the dewetting speed is constant. A constant dewetting speed of 8 mm-s has been measured when a liquid film of tricresyl phosphate (TCP) dewets on Teflon PFA, a hard fluoropoly-mer of low surface free energy (p. = 250 MPa, 7 = 20 mJ-m ). 

FIG. 10 Formation of a dry patch (zone) in an unstable liquid film on a rigid substrate. 

Some comparative dewetting experiments were conducted on a fluoropolymer. Teflon PFA (du Pont de Nemours and Co.) representing a relatively rigid substrate (p, = 250 MPa) with similar surface characteristics (surface free energy ys = 20 mJ m ). 

Fig. 16 Structures of xestospongin A (116) and of a less rigid substrate employed for an alternative synthesis of both 116 and xestospongin C (128)...

L. K. P. Lam, J. B. Jones, Enzymes in Organic Synthesis. 43. Investigation of the Preferred Orientation of Ester Groups in Pig Liver Esterase Catalyzed Hydrolyses Using Conformationally Rigid Substrates , J. Org. Chem. 1988, 53, 2637 - 2639. 

ISO 11003-1 2001 Adhesives - Determination of shear behaviour of structural adhesives -Part 1 Torsion test method using butt-bonded hollow cylinders ISO 11003-2 2001 Adhesives - Determination of shear behaviour of structural adhesives -Part 2 Tensile test method using thick adherents ISO 13445 2003 Adhesives - Determination of shear strength of adhesive bonds between rigid substrates by the block-shear method... 

ISO 813 1997 Rubber, vulcanized or thermoplastic - Determination of adhesion to a rigid substrate - 90 degree peel method... 

It is a well known fact that the vibration frequency of the internal stretch mode of CO decreases from its gas phase value of 2143 cm on chemisorption onto a metal surface. In general terms, depending on the adsorption site it takes values between 2000-2100 cm Mn the ontop position, 1900-2000 cm" when bridgebonded and 1800-1900 cm for molecules in the hollow site. The vibration frequency of a particular system is of course the total effect of the different kinds of interactions sketched in Fig. 2. For example, simply the fact that the oscillator is attached to a more or less rigid substrate so that the... 

To study the effect of conformationally more rigid substrates, some cyclic allylic esters (23 and 24) were employed as substrates. Reaction of these with n-BuMgl, employing 19b as catalyst, produced very low ees, however (Scheme 8.19) [35]. 

UV curable coatings are applied to a variety of flat, rigid substrates, such as particle board, medium- and high-density fiberboard, wood veneers, polycarbonate, poly(methylmethacrylate), paper, and metal sheets and foils. An example of a formulation for UV curable coatings is in Table 7.1. 

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