Conductivity of mixtures

In general, the thermal conductivities of liquid mixtures, and gas mixtures, are not simple functions of composition and the thermal conductivity of the components. Bretsznajder (1971) discusses the methods that are available for estimating the thermal conductivities of mixtures from a knowledge of the thermal conductivity of the components. 

Figure 7 The change of conductivity when isobutylene is added very slowly to solutions of aluminium halide in alkyl halide at ca. -78 °C. No polymerisation occurred in any of these experiments. The experimental conditions are specified in Table 3. The point marks the conductivity of mixture C7 when it was warmed to 0 °C...

Figure 15.6 is a plot of the thermal conductivity of mixtures of helium and nitrogen obtained on an apparatus similar to that described in the next section. Characteristically, the thermal conductivity of most mixtures does not vary linearly with concentration. The slope of the curve at any point determines the value of A/c and, therefore, the detector response. Figure 15.6 also illustrates that the greater the difference between thermal conductivities of the adsorbate and carrier gas, the higher will be the slope and therefore the detector response. 

E. Bouty found that nitrates dissolved in cone, nitric acid raise the conductivity in proportion to the amount dissolved. A. Klemenc and R. Scholler measured the conductivity of mixtures of nitrous and nitric acids, but obtained no definite evidence of the existence of H2N308. Observations on the temp, coeff. were made by P. Kohlrausch and O. Grotrian, C. Deguisne, and J. and G. E. Gibson. According to S. Arrhenius, the temp, coeff. between 18° and 52°, is ... 

Room-Temperature Conductivities of Mixtures of Various Ammonium ... 

I. The dielectric constants and conductivities of mixtures composed of isotropic substances. Ann. Phys. (Leipzig) 24, 636-664 (1935) 665-679 (1935)... 

For heterogeneous materials, the effect of geometry must be considered using structural models. Utilizing Maxwell s and Eucken s work in the field of electricity, Luikov et al. [105] initially used the idea of an elementary cell, as representative of the model structure of materials, to calculate the effective thermal conductivity of powdered systems and solid porous materials. In the same paper, a method is proposed for the estimation of the effective thermal conductivity of mixtures of powdered and solid porous materials. 

COEFFICIENTS OF THERMAL CONDUCTIVITY OF MIXTURES OF COPOLYMERS OF BUTADIENE AND ACRYLONITRILE AS FUNCTIONS OF ADMIXTURE CONTENT AND TEMPERATURE. 

THERMAL CONDUCTIVITY OF MIXTURES IN THE DENSE GASEOUS STATE. THE METHANE-CARBON TETRAFLUORIDE SYSTEM. 

We calculate from the above equation for the thermal conductivity of mixture ... 

Still being debated [33], the high conductivity of the mixtures containing >25% RuOa has been attributed [34—36] to the formation of an infinite chain of RUO2 clusters in the Ti02 matrix. The breakdown of this chain has resulted in the poor conductivity of mixtures with <25% Ru02. 

Fig. 3. Apparent thermal conductivity of mixtures of ground Santocel A and aluminum powcfer.

Bruggeman DAG (1935) Dielectric constant and conductivity of mixtures of isotropic materials. Ann Phys 24 636-679... 

Many models have been proposed (117) to explain the electrical conductivity of mixtures composed of conductive and insulating materials. Percolation concentration is the most interesting of all of these models. Several parameters, such as filler distribution, filler shape, filler/matrix interactions, and processing technique, can infiuence the percolation concentration. Among these models, the statistical percolation model (118) uses finite regular arrays of points and bonds (between the points) to estimate percolation concentration. The thermodynamic model (119) emphasizes the importance of interfacial interactions at the boimdary between individual filler particles and the polymeric host in the network formation. The most promising ones are the structure-oriented models, which explain condnctivity on the basis of factors determined from the microlevel stmctin-e of the as-produced mixtures (120). 

Carbon or metallic filaments had limited life because of poor sealing technique of the glass bulb. A filament stable in air seemed indeed an elegant solution. Nernst having realised the adequate conductivity of mixtures of oxides at high temperature and amongst them probably stabilised zirconia, demonstrated also that the conductivities were ionic. 

Electrolytes for Rechargeable Batteries, Table 3 Conductivity of mixture of salts and solvents ... 

The electrical conductivity of mixtures of electrolytes and non-electrolytes are scarce. The only systems studied above 200 °C are KCl - Ar (Hartmann and Franck, 1969), NaCl-dioxane (Yeatts and Marshall, 1972) and Nal - methanol (Korobkov and Mikhilev, 1970). In these cases the system can be considered as a binary electrolyte solution in a mixed solvent. Therefore, the specific and molar conductivity decreases with the increase of the non-electrolyte in water due to the reduction of the dielectric constant of the mixed solvent. 

Bianchi, H. (1990) Conductivity of mixtures of symmetrialc and unsymmetrical electrolytes in aqueous solutions. Thesis, University of Buenos Aires. 

Heat conductivity of mixture gas Heat conductivity of mixture gas at high pressure Am[kJ/(m h °), total pressure p (MPa) and temperature t (°) can be estimated by following equations ... 

In order to discuss the evaluation of the thermal conductivity of mixtures containing polyatomic components it is useful to treat the results of the Wang Chang and Uhlenbeck expansion method and that of Thijsse separately. The former is well established but, in its full form, is sufficiently complicated that it has seldom been used for calculations (see. 

Here, Xhe is the Hirschfelder-Eucken result for the thermal conductivity of the mixture and AX is a relatively small term (of the order of a few percent of the total thermal conductivity) that contains all of the explicit effects of inelastic collisions. The complete expression for AX has been given by Monchick et al. (1965) and Maitland et al. (1987) in a form that contains largely experimentally accessible quantities. However, because there are in fact very few measurements of these quantities it is difficult, if not impossible, to evaluate this term for most systems. Thus, most evaluations of the thermal conductivity of mixtures have been performed with AX = 0 and so with the Hirschfelder-Eucken expression (4.127). 

Recent work (Vesovic Wakeham 1993) has concentrated on the use of the Thijsse formulation of the thermal conductivity of mixtures because of its relative simplicity and the hope that the accuracy of even simpler approximate forms of it may approach that found for pure gases (Section 4.2.4.3). At present the available results are confined to the special case of a binary mixture of an atomic species, B, and a rigid-rotor species. 

Early calculations with this formulation (Vesovic Wakeham 1993) suggest that the explicit terms connected with the inelasticity of the pair potential are small, so that it may provide a simpler route to the prediction of the thermal conductivity of mixtures if the result for atom-rigid-rotor systems is more general. The development of this alternative formulation and of methods for the evaluation of effective cross sections for realistic non-spherically symmetric potentials are active lines of research. 

Kestin, J., Nagasaka, Y. Wakeham, W.A. (1982). The thermal conductivity of mixtures of carbon dioxide with three noble gases. Physica, 113A, 1-18. 

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