Linear dilatation coefficient

In the interferometric dilatometer, the change in length of the sample causes the movement of interference fringes. Knowing the laser wavelength and counting the moved fringes, it is possible to deduce the dilatation of the sample. Hereafter, we shall briefly describe a very simple interferometric dilatometer used for the measurement of the linear contraction coefficient of Torlon. For a more detailed description of this dilatometer, see ref. [53],... 

Figure 3. Generalized thermodynamic quantities calculated for a Lennard-Jones KrAr binary mixture (left) and molten LiF alloy (right) the generalized dilatation 6(k) the generalized linear thermal expansion coefficient ckt (fc) the generalized specific heat at constant volume Cy (fc) (the filled boxes at k = 0 correspond to the values obtained directly in MD simulations) and the generalized ratio of specific heats 7(k).

The test method covers determination of the coefficient of linear thermal expansion for plastic materials, using a vitreous silica push-rod dilatometer. Vitreous silica is also known as fused silica quartz. Dilatometer is an expansion-meter, as dilation is expansion of materials when they are heated. The test method recommends that ASTM E 228 shall be used for temperature range other than -30 to 30°C, because ASTM E 228 operates in the temperature range of -30 to 140°F (-34°C to +60°C). 

Increases in system temperature give rise to volume dilation, resulting in increased amounts of free volume. This explains the strong tendency for the diffusion coefficient to increase with temperature. The free-volume fraction in Eq (20.4-4) may be represented as a linear addition of the several variables that affect its value ... 

A review of the theoretical basis, finite-element model, and sample applications of the program NOVA are presented. The updated incremental Lagrangian formulation is used to account for geometric nonlinearity (i.e., small strains and moderately large rotations), the nonlinear viscoelastic model of Schapery is used to account for the nonlinear constitutive behavior of the adhesive, and the nonlinear Fickean diffusion model in which the diffusion coefficient is assumed to depend on the temperature, penetrant concentration, and dilational strain is used. Several geometrically nonlinear, linear and nonlinear viscoelastic and moisture... 

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