Dilation deformation

Studies of the equilibrium and dynamic adsorption behaviour of biopolymers at liquid interfaces in combination with thermodynamic and kinetic models allow us to draw conclusions about the structure of the interfacial layer. Additional information can be obtained from rheological investigations, both under shear and dilational deformations. 

From this figure we learn that pure deformation without any change in size (pure shear) and change in size without any change in shape of the body (dilatation or compression) have to be considered. For the latter case the tensor of strain becomes Uj,j 8 (Landau Lifschitz 1953). Any deformation can be given as the sum of pure shear and dilatation deformations. Therefore, we get... 

The effect of MR on the rheological properties of lysoz5mie adsorption layers at the air/solution (0.05 M phosphate buffer, pH 6.0) interface at 25°C was studied using a d5mamic drop tensiometry and dilatometry methods. The quasi-equilibrium adsorption layers (the formation time of 60,000-70,000 sec) were subjected to compression/dilatation deformation sinusoidally in the field of linear viscoelasticity. 

The adsorption experiments with lysozyme indicate that the trough method may be a way of obtaining the adsorption kinetics of other globular proteins, including )S-lactoglobulin. This is necessary for the complete analysis of the response of an adsorbed film to a dilatational deformation. In order to use the method, however, reliable values of n and A area are required. 

Freer, E. M., Yim, K. S., Fuller, G. G., Radke, C. J. (2004). Interfacial rheology of globular and flexible proteins at the hexadecane/water interface Comparison of shear and dilatation deformation. Journal of Physical Chemistry B, 108, 3835-3844. 

Vorticity The relative motion between two points in a fluid can be decomposed into three components rotation, dilatation, and deformation. The rate of deformation tensor has been defined. Dilatation refers to the volumetric expansion or compression of the fluid, and vanishes for incompressible flow. Rotation is described bv a tensor (Oy = dvj/dxj — dvj/dxi. The vector of vorticity given by one-half the... 

The stress has an isotropic contribution due to fluid pressure and dilatation, and a deviatoric contribution due to viscous deformation effects. The deviatoric contribution for a Newtonian fluid is the three-dimensional generalization of Eq. (6-2) ... 

In order to reproduce the temperature variation of the lattice constants, the anisotropy of the lattice expansion has to be taken into account. For this purpose, the tensor of thermal expansion ot is introduced instead of the scalar a , and the tensor of deformation due to the HS <- LS transition is employed instead of the dilation (Fh — Fl)/Fl. Each lattice vector x T) can now be... 

This has been verified for polydimethylsiloxanes added to crude oils. The effect of the dilatational elasticities and viscosities on crude oil by the addition of polydimethylsiloxanes is shown in Table 21-1. Under nonequilibrium conditions, both a high bulk viscosity and a surface viscosity can delay the film thinning and the stretching deformation, which precedes the destruction of a foam. There is another issue that concerns the formation of ordered structures. The development of ordered structures in the surface film may also stabilize the foams. Liquid crystalline phases in surfaces enhance the stability of the foam. 

No effects in humans have been reported. Intratracheal administration of 50 mg of yttrium oxide in rats caused granulomatous nodules to develop in the lungs by 8 months. Nodules in the peribronchial tissue compressed and deformed several bronchi the surrounding lung areas were emphysematous, the interalveolar walls were thin and sclerotic, and the alveolar cavities dilated. Intraperitoneal injection... 

In displacive transitions only small changes in the arrangement of coordination polyhedra occur. Reconstructive transitions would require the breaking and making of bonds, but the same can be accomplished by a simple dilatational mechanism. Buerger proposed such a mechanism for the transformation from the CsCl structure to the NaCl structure (Fig. 4.10). Such deformational relations are known to exist between... 

Fluids with shear stresses that at any point depend on the shear rates only and are independent of time. These include (a) what are known as Bingham plastics, materials that require a minimum amount of stress known as yield stress before deformation, (b) pseudoplastic (or shear-thinning) fluids, namely, those in which the shear stress decreases with the shear rate (these are usually described by power-law expressions for the shear stress i.e., the rate of strain on the right-hand-side of Equation (1) is raised to a suitable power), and (c) dilatant (or shear-thickening) fluids, in which the stress increases with the shear rate (see Fig. 4.2). 

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