Coefficient of elasticity

It is therefore important to determine how the volume of the mixture varies with pressure and temperature if the system exists in the gel state. Because of the low Young s modulus in rubber gels, no strongly anisotropic tension distribution can exist. The volume dependence can therefore be determined by one-sided loading and deformation, as can be applied in a hydraulic press. The compressibility can be obtained from one-sided deformation without determining the other coefficients of elasticity. 

Instead of measuring the force-temperature dependence at constant volume and length, one can measure this dependence at constant pressure and length but in this case it is necessary to introduce the corresponding corrections. The corrections include such thermomechanical coefficients as iso-baric volumetric expansion coefficient, the thermal pressure coefficient or the pressure coefficient of elastic force at constant length 22,23,42). 

Elinvar, 34% Ni, 57% Fe, 4% Cr, 2% W, has a very low temperature coefficient of elasticity which makes it useful for springs in watches and precision instruments. 

To say nothing about atoms, valence angles and so on, one can notice that the length of a macromolecule is much larger than its breadth, so one can consider the macromolecule as a flexible, uniform, elastic thread with coefficient of elasticity a, which reflects the individual properties of the macromolecule... 

In the simplest case, at N = 1, the considered subchain model of a macromolecule reduces to the dumbbell model consisting of two Brownian particles connected with an elastic force. It can be called relaxator as well. The re-laxator is the simplest model of a macromolecule. Moreover, the dynamics of a macromolecule in normal co-ordinates is equivalent to the dynamics of a set of independent relaxators with various coefficients of elasticity and internal viscosity. In this way, one can consider a dilute solution of polymer as a suspension of independent relaxators which can be considered here to be identical for simplicity. The latter model is especially convenient for the qualitative analysis of the effects in polymer solutions under motion. 

Keywords multiwall carbon nanotubes (MWNT), polytetrafluoroethylene (PTFE), surface groups, conventional yield strength, coefficient of elasticity... 

In Fig. 4 there are shown compression plots for composite materials obtained by mixing of PTFE (F-4PN20) and MWNT powders with following hot pressing. The curves 1-3 corresponds to composites containing MWNT with different surface state, 4 - pure PTFE. In Table 3 there are listed conventional yield strength and coefficients of elasticity calculated from compression plots. 

The Gibbs coefficient of elasticity, e, was introduced as a variable resistance to surface deformation during thinning ... 

According to all molecular theories of solids hitherto propounded, and to all experimental evidence, the coefficient of elasticity does not change much more at low temperatures, and has therefore a finite value even at the absolute zero. Consequently the coefficient of thermal expansion must also converge towards zero at low temperatures, i.e. we must have... 

The hydrocarbon molecules undergo a stress from the pore in the diffusion. When the diffusing molecule is assumed to be a sphere, this stress is represented by /l A, where (i is the coefficient of elasticity, and J Is the strain [18]. However, the shape of a hydrocarbon molecule is markedly different from a sphere, since the molecule within the pore touches the pore surface at some points. Therefore, the following assumptions has been made the shape of the hydrocarbon molecule is regarded as a series of spheres linked together, and the diameter of each sphere is equ.al to the minimum size (d ) of the hydrocarbon molecule. The number of the spheres is represented by (L,yd ), where is the length of the hydrocarbon molecule. Under these assumptions, the hydrocarbon molecule undergoes the... 

The first partial derivative on the right represents the coefficient of elasticity of the gas, the second is nothing but the so-called coefficient of increase of pressure with temperature at constant volume. If the change takes place at constant pressure, dp = 0, and (3) may be written in the forms... 

The coefficients of elasticity describe strains caused by stress. The two moduli of linear elasticity for isotropic solids are well known ... 

The properties of a nanocomposite are determined by the stmcture and properties of the nanoelements, which form it. One of the main tasks in making nanocomposites is building the dependence of the stmcture and shape of the nanoelements forming the basis of the composite on their sizes. This is because with an increase or a decrease in the specific size of nanoelements (nanofibers, nanotubes, nanoparticles, and so on), their physical— mechanical properties such as coefficient of elasticity, strength, deformation parameter, and so on, are varying over one order [1-5]. 

Combining the Eqs. (83) and (84) for determination of the coefficient of elastic component of viscosity in Eq. (77) we finally find accurate within a multiplier neared to the one ... 

Ektar Performance Plastic s trade name for its family of copolyester thermoplastic elastomer, elastic constant See modulus of elasticity, elastic deformation See deformation, elastic en-ergy, plastic work rheology, elastic fracture See melt fracture, elastic hysteresis See hysteresis, elastic, elasticity A property that causes plastic to return to its original size and shape after removal of a force causing deformation. See coefficient of elasticity deformation and toughness extruder-web stretching and... 

Table 3.3 Temperature coefficients of elastic stiffness (TCij) for a-quartz (After Newnham, 1975.) ...

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