Linear isobaric expansivity

Because fhe molar volumes and densities of ILs are usually linear functions of femperature, fhe isobaric expansivities are easy to obtain from linear fifs of fhe densify dafa. The values of ILs are in the range of 4 6 X... 

There are only two papers describing the physical properties of discotic LCEs [35, 36]. X-ray diffraction showed that a narrower azimuthal intensity distribution can be obtained when a second crosslinking step is done under an external load reflecting a macroscopic alignment parallel to the direction of the external stress [35]. X-ray diffraction experiments on monodomains (LSCE) show the occurrence of sharp maxima in the azimuthal distribution. Thermal expansion has also been studied for polydomain LCEs and for LSCEs in [36]. It is found that well inside the discotic phase, that is sufficiently far below the discotic-isotrop-ic transiton, the length parallel to the stress axis of both, poly- and monodomain samples, increases approximately linearly with increasing temperature as expected from the isobaric expansion of the network. 

The expansibilities, compressibilities, and surface tensions of the mixtures are intensive properties, so they should be expressed not in terms of excess quantities but just as deviations from the linear dependence on the (mole fraction) composition. Data for the isobaric expansibilities and the adiabatic compressibilities of binary mixtures of water with many cosolvents on the list are available in [56]. The isobaric compressibilities can then be calculated from such data by Equation 3.3, using also the molar volumes of the mixtures, V = x V- + XcK -i- V. ... 

Microscopic ionic volumes of RTILs, the sums of the constituent 20 cations and 20 anions Vj = v+ + v, were calculated by several theoretical methods according to Preiss et al. [49] and compared with the crystal volumes obtained from x-ray diffraction (Table 2.4). It was then shown that several physical properties were linear with these microscopic volumes the molar volume V, the isobaric expansibility ap, the molar heat capacity Cp, the (logarithm of) the viscosity In , and the (logarithm of) the molar conductivity InA all these obey the relation a + bv. ... 

In Isothermal conditions a constant inlet gas pressure would automatically maintain a constant volumetric and linear flow rate. When the temperature of the column is programmed while the inlet gas pressure is kept constant, the flow rate will change considerably, becoming lower because of the modifications of the column geometry, expansion of the gas, and modifications of the gas viscosity, which increases with (T) . Besides isobaric operation, which is common, constant flow at programmed temperature capability is also available for certain instruments. 

Figure 3 Transitiometric investigation of the pressure effect on the isobaric thermal expansivities a. of gaseous, liquid, and solid substances (a) comparison between calculated ana experimental data of methane at 333 K (bl) quinoline as a simple fluid (b2) water as the associated liquid (cl) effect of temperature on medium-density polyethylene (MDPE) (c2) evolution of with the crystallinity (points represent the experimental data and the lines were obtained by the least squares fitting of data) (c3) comparison between the experimental a for three polyethylenes with different degrees of crystallinity and the predicted values for crystal and amorphous phases obtained by extrapolation from linear fitting of the experimental data...

In the last decade, accurate microcalorimetric and atomic force microscopy experiments have provided detailed information on the lipid melting processes [113-118]. Interestingly, a linear relationship between the isobaric heat capacity and the volume expansion with temperature has been observed for a variety of lipids [115-118] leading to the interpretation that proportional enthalpy and volume changes at the melting transition would be driven by intrinsic structural changes within the lipid molecules, whereas the changes of free volumes and intermolecular interactions could be considered as perturbations [116]. 

---