INDEX isothermal compressibility

By an assortment of thermodynamic manipulations, the quantities dn/dp and [N (d G/dp )o] can be eliminated from Eq. (10.48) and replaced by the measurable quantities a, /3, and dn/dT the coefficients of thermal expansion, isothermal compressibility, and the temperature coefficient of refractive index, respectively. With these substitutions, Eq. (10.48) becomes... 

Many of the unusual properties of the perfluorinated inert fluids are the result of the extremely low intermolecular interactions. This is manifested in, for example, the very low surface tensions of the perfluorinated materials (on the order of 9-19 mN jm. = dyn/cm) at 25°C which enables these Hquids to wet any surface including polytetrafluoroethene. Their refractive indexes are lower than those of any other organic Hquids, as are theh acoustic velocities. They have isothermal compressibilities almost twice as high as water. Densities range from 1.7 to 1.9 g/cm (l )-... 

Evaluations of Rd and Y necessitate a knowledge of certain physical properties of the two liquids and the mixtures. The variation of refractive index with concentration is measured readily by refractometry, if I nT, — n21 is large. The coefficient of isothermal compressibility of a mixture t2 requires specialised equipment. Alternatively, it can be determined from the heat capacity and the coefficient of isentropic compressibility87, 88, the latter being yielded from velocity of sound data88. However, provided and 02 for the pure compounds are known, j312 is evaluated most conveniently on the basis of additivity, thus ... 

The thermophysical and thermodynamic properties of liquid water as well as its chemical properties, all depend on the temperature and the pressure. The thermophysical and thermodynamic properties include the density p, the molar volume V = M/p, the isothermal compressibility/ct = P (dp/d P)t = —V (dV/dP)T, the isobaric expansibility ap = —p dp/dT)p = V dV/dT)p, the saturation vapour pressure p, the molar enthalpy of vapourization Ayf7, the isobaric molar heat capacity Cp, the Hildebrand solubility parameter 3h = [(Ay// —RT)/ the surface tension y, the dynamic viscosity rj, the relative permittivity Sr, the refractive index (at the sodium D-line) and the self-diffusion coefficient T>. These are shown... 

NIST/ASME Steam Properties Database versiou 2.21 http //www.nist.gov/srd/nistlO.cfm (accessed November 10, 2010) (purchase required). Thermophysical properties include in the STEAM Database temperature, Helmholtz energy, thermodynamic derivatives, pressure, Gibbs energy, density, fugacity, thermal conductivity, volume, isothermal compressibility, viscosity, dielectric constant, enthalpy, volume expansivity, dielectric derivatives, internal energy, speed of sound, Debye-Hlickel slopes, entropy, Joule-Thomson coefficient, refractive index, heat capacity, surface tension. The STEAM database generates tables and plots of property values. Vapor-liquid-solid saturation calculations with either temperature or pressure specified are available. 

Here, Ag is the wavelength of light in vacuum, n is the refractive index, is the Boltzmann constant, T is the absolute temperature, 0 is the isothermal compressibility, N is the number of scattering units per unit volume, and 5 is the mean square of the anisotropic parameter of polarizabihty per scattering unit. Finally, from the definition of the turbidity t in Equation 2.12, the fight scattering loss (dB/km) is related to the turbidity t (cm ) by... 

Table 2.3 shows the calculated and observed values of the isothermal compressibility, refractive index, and isotropic light scattering of PMMA and PSt. The calculated values for both polymers show good agreement with the measured values. 

The index of refraction of the material in the layer can be estimated to be 1.333. The total intensity of the quasi elastically scattered light is proportional to the isothermal compressibility. From intensity measurements we estimate it to be about a factor 500 higher than the compressibility of water at O C. A diffusion constant, which describes the dynamics of the entropy fluctuations, has been determined to be about 3 10" cm /s. This value has to be compared with the thermal diffusivity in water a 10 cm /s or the constant for self diffusion in water Djj20 lO" cm /s. 

Here io is the wavelength of light in vacuum k, the Boltzmarm constant T, the absolute temperature n, the refraaive index fS, the isothermal compressibility. The fluctuation theory for... 

During the compression isotherms, refractive index data were collected. The refractive index, ( >), is modeled by ... 

Figure 7c reflects that the layers of hydrophobic particles exhibited similar refractive index values that had been characteristic of the hydrophilic ones when the hydrophobic layer was compressed near to point B on the isotherm (Fig. 5b). That could mean that when the layer structure broke up (see also Fig. 7b), the fragments of the broken layer might have sunk deeper in the water phase (Fig. 7a), but these experimental results need further confirmation.

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