Argon critical isotherm

The results for nitrogen, argon and krypton adsorption on pristine MCM-48 materials can be summarized as follows (i) Argon sorption isotherms at 87 K (T/Tc = 0.58, where Tc is the critical temperature of the bulk fluid) reveal for all MCM-48 silica phases used in this study pore condensation but no hysteresis at relative pressures p/po < 0.4. With increasing pore size... 

A few of the features and limitations of the cubic equation can be illustrated neatly by considering the critical isotherm. Since T is fixed, we need not concern ourselves with the temperature dependence of the parameters moreover, since T = Tc, we can use the critical constraints treated in the preceding section. The example which follows is inspired by a study reported by J. J. Martin (2), and I shall use the same data used by Martin values of Pr and Vr for argon at Tr = 1, read to within about dt 1% from graphs prepared by Costolnick and Thodos (4). 

Table II. Results of Parametric Studies of the Critical Isotherm of Argon...

Table III. The Critical Isotherm of Argon, as Calculated from the Redlich—Kwong, Berthelot, and van der Waals Equations...

The dependence of a on the density has been introduced as a semi-empirical function [37]. The parameters of this function have been obtained by fitting to experimental and theoretically obtained data of the critical isotherm of argon. Argon has been chosen as the reference fluid because of its simple molecular interaction. With scaling parameters this function obtained for argon can be applied to other substances. 

Figure 3 was constructed as mentioned previously from Fig. 2 by cross-plotting isotherms of reduced conductivity vs. A. The thermal conductivity data for carbon monoxide were not used. Then from Fig. 3 the values of k for tritium (A = 1.00) were obtained to predict the temperature dependence of the thermal conductivity of tritium along the vapor pressure curve as shown in Fig, 2. Lastly, it may be pointed out that an extension of the Ne data of Ldchtermann P ] to the critical-temperature locus would appear to give some values of the thermal conductivity which would be very near to those predicted for tritium, and would also require an S-shaped curve, which seems improbable in view of the value of T for neon, i.e, 1.247. A curve for the thermal conductivity of Ne predicated upon behavior similar to argon and tritium is also shown. Derivation of the thermal conductivities of the unsymmetrical isotopic species of hydrogen—HT, HD, and DT— is a triviality and can easily be obtained from Fig. 3. Note that de Boer s theory does not distinguish between the behavior of HT and D2 P ]. For the unsymmetric isotope HT the value of A should be computed after Friedmann [ ] as...

Levelt Sengers has examined the antisymmetry character of argon isotherms with respect to the critical isochore (p = p or and has found that... 

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