Electrical conductivity data

As described in the introduction, certain cosurfactants appear able to drive percolation transitions. Variations in the cosurfactant chemical potential, RT n (where is cosurfactant concentration or activity), holding other compositional features constant, provide the driving force for these percolation transitions. A water, toluene, and AOT microemulsion system using acrylamide as cosurfactant exhibited percolation type behavior for a variety of redox electron-transfer processes. The corresponding low-frequency electrical conductivity data for such a system is illustrated in Fig. 8, where the water, toluene, and AOT mole ratio (11.2 19.2 1.00) is held approximately constant, and the acrylamide concentration, is varied from 0 to 6% (w/w). At about = 1.2%, the arrow labeled in Fig. 8 indicates the onset of percolation in electrical conductivity. 

In a typical survey carried out in an estuary, the analyst may be presented with several hundred samples with a wide range of chloride contents. Before starting any analysis, it is good practice to obtain the electrical conductivity data for such samples so that they can be grouped into increasing ranges of conductivity and each group analysed under the most appropriate conditions. 

D. The electrical conductivity data support the rationale just provided The greater the number of particles, which in this case are ions, the higher the B.P. 

CASE 4 - Determination of areas characterized by salt water intrusion (integrated evaluation of geophysical data and electrical conductivity data from direct investigations in monitoring wells)... 

The synthesis of [RuL] where H2L = 2,3-naphthalocyanine has been reported. Reactions with suitable bridging ligands lead to oligomers, electrical conductivity data for which have been compared with those of related compounds. The tetrakis(tert-butyl) derivative [Ru ( BU4L)] has been prepared by the thermal decomposition of the [Ru( Bu4L)(Lax)2] (Lax = NH3, 3-Clpy). ... 

A metallic band structure is realized when the CT solids have a partial CT state and molecules form uniform segregated columns or layers. Figure 1 shows electrical conductivity data for 1 1 low-dimensional TTF TCNQ system, as a function of redox potentials [82]. The two lines a and b are related to the equation expressing the relationship between 7d, Ea, and the Madelung energy M 5) (5 = degree of CT) between partially charged component molecules (eq. 2) [83], where and Ea are... 

Figure 6.29 Diffusion coefficient measured directly (open circles) and calculated from electrical conductivity data (closed circles) for Na+ in sodium chloride. From W. D. Kingery, H. K. Bowen, and D. R. Uhhnann, Introduction to Ceramics. Copyright 1976 by John Wiley Sons, Inc. This material is used by permission of John Wiley Sons, Inc.

Polyvinyl Chloride. Biswas and Moitra [102] observed substantial increase in conductivity for metal modified PVC (Fig. 29). Table 1 presents the electrical conductivity data of the PVC-DMG-M(II) complexes. Interestingly, conductivities appreciably increase relative to PVC in the order PVC < PVC-DMG-Cu(II) < PVC-DMG-Ni(II) < PVC-DMG-Co(II). The enhancement in the conductivity is readily ascribable to the varying extents of charge transfer between the 3d metal ion centers and the electron-rich heteroatoms in DMG. Apparently, ease of such charge transfer will depend upon the availability of M vacant orbitals which follows the order Co2 + (3d1) > Ni2+(3d8) > Cu2 + (3d9). 

Equations (1.194) and (1.195) can be accepted, within reason, because both the chemical equilibrium constants and the hole mobility for semiconductors have an Arrhenius-type temperature dependence. It has been shown, by a least-square fitting of the electrical conductivity data of Maruenda et al. to eqn (1.193), that 85 per cent of the data points are within 1.5 per cent of the calculated values, as shown in Fig. 1.58. This indicates that the model proposed here gives an accurate description of the data. The fitting parameters are listed in Table 1.5. 

The triple ion formation can be checked by the electric conductivity data. In Fig. 12, the equivalent conductance (A) is given as a function... 

Another subtle case, where specific interactions may obscure the effects of Coulombic criticality, is ethylammonium nitrate (EtNH3N03) +l-octanol (Tcs315K) [85], In contrast to all other known examples, the critical point is located in the salt-rich regime at a critical mole fraction of Xc = 0.77. Electrical conductance data indicate strong ion pairing, presumably caused by a hydrogen bond between the cation and anion which stabilizes the pairs in excess to what is expected from the Coulombic interactions [85]. This warns that, beyond the Coulombic/solvophobic dichotomy widely discussed in the literature, additional mechanisms may affect the phase separation [5]. 

In concluding this section on liquid-liquid phase transitions, we briefly consider the available experimental information on the ion distribution near criticality. In the absence of scattering experiments, most experimental data come from electrical conductance data [72, 137, 138]. Moreover, there are some data on the concentration dependence of the dielectric constant in low-s solutions [139] and near criticality [138]. 

The basicity of phosphoric acid appears different when it is neutralized with sodium hydroxide according to the indicator employed—vide supra—and the electrical conductivity data explain how the acid was once considered by M. Berthe-lot and W. Louguinine, A. Joly, D. Berthelot, P. Walden, and J. B. Senderens to... 

In summary, the effect of porosity on electrical conductivity and ion diffusivity in agarose gels is studied. Both electrical conductivity and ion diffusivity increase with porosity. The model obtained from the electrical conductivity data, i.e., Equation (7), can predict the diffusivity of macromolecules in 2% agarose gel for solutes with hydrodynamic radius less than the pore size of the gel. This study suggests that electrical conductivity method used in this study can be applied to investigating diffusion behavior of macromolecules in uncharged porous media. 

Bloom et al. [62] showed that the composition of complex ions in melts can differ from that of minimum conductivity, because the complex ions are in equilibrium with the simple ions, so that the maximum negative deviation from the additive conductivity would not correspond to the stoichiometry of the complex ions. Other researchers [63,64] found that the stoichiometry of complex ions is influenced by the maximum value of the activation energy. In any case, the electrical conductivity data must be correlated with other physicochemical data, such as phase diagrams, Raman spectra, minimum thermodynamic activities, to obtain the composition of complex ions. 

It is a useful way, in practice, to look for phase transitions in organic conductors by means of the electrical conductivity data. Thus when a peak is detected at some temperature in the derivative of the slope function 5(7), it is a reasonable indication of the existence of a transition at this temperature. The width of this peak in temperature is also an indication of the width of the transition. 

Qn(TCNQ)2, (DMDCNQI)2Ag, and (TMTTF)2PF6 The metal-like semiconductor model of Epstein et al. (see Section II.C) has been found to fit rather nicely the electrical conductivity data a(T) of the quinolinium salt Qn(TCNQ)2, for instance [16]. In this case, the experimental values of the fitting parameters were A0 = 600 K, a = 2.7, and Tm = Aq/u = 240 K. 

In the middle of cells and in faces that are perpendicular to the flowing direction, the borders are branched, which means that the effective number of borders, equivalent to that in a real system, is different from five. The number of independent borders with constant by height radius and length L can be determined by the electro-hydrodynamic analogy between current intensity and liquid flow rate through borders, both being directly proportional to the cross-sectional areas [6,35]. This analogy indicates that the proportionality coefficients (structural coefficients B = 3) in the dependences border hydroconductivity vs. foam expansion ratio and foam electrical conductivity vs. foam expansion ratio, are identical [10]. From the electrical conductivity data about foam expansion ratio it follows... 

Composition and electrical conductivity data for HOPG/MF0 and HOPG/ASF5/F2 intercalates... 

Electrical conductivity data on Brp3 have been interpreted in terms of partial dissociation into BrFj and BrF ions, and this is supported by the preparation and reactions of the fluorobromonium salts (b) ... 

Table 2 shows electrical conductivity data of the catalysts and the support. A is the electrical conductivity of alumina. B is the electrical conductivity of Sn and alkali metals promoted alumina. C is the electrical conductivity of Pt catalyst while D is the electrical conductivity of Pt-Sn catalyst. E is the electrical conductivity of Pt-Sn-Alkali metals catalyst. The data shows that the addition of metal to alumina increases electrical conductivity. The addition of Sn to Pt catalyst augments electrical conductivity approximately three times. Further incorporation of the alkali metals results in an order of magnitude further increases. 

Pt-Sn alloy formation. The synergistic mechanism model for Sn and the alkali metal are shown in Figure 5. Table 2 Electrical conductivity data of catalysts and support ... 

In this contribution, we present a first-principles study of the structure and energetics of Bjerrum defects in ice h using a large supercell subject to periodic boundary conditions. The results are interpreted in the context of experimental electrical conductivity data for doped ice Ih, using the framework of Jaccard s defect-based microscopic electrical theory of ice ... 

The excess electron in the metal could not be quantified from electrical conductivity data. On electrostatic grounds, it does not seem possible to transfer a great number of electrons sufficient to reach unity for e/M, This is confirmed by simple considerations on the reduction level of titania and the relative molar ratio n /n. It seems more reasonable to think in terms of "long" dIstance2influence. For instance, since and CO chemisorb on the metal surface as dipoles with a donor character, even a small excess of electrons in the metal or at its interface with the support will counteract this chemisorption. 

Tanase, S. Miyazaki, Y. Yanagida, M. Tanimoto, K. Kodama, T. Numerical formulation of electrical conductance data of molten alkali carbonates. Prog. Batteries Solar Cells 1988, 7, 396-402. 

In general the charge carriers in mixed proton-electron conducting materials could be protons, oxygen ions (or oxygen vacancies), hydroxyl ions, electronic-holes and electrons. To determine the nature of the charge carriers and their transport numbers, various defect structure models have been presented [36-38]. These defect models were fitted to the total electrical conductivity data measured... 

TABLE 5-1. Electrical Conductivity Data of Rare Earth Sesquioxides R2O3). Reprinted with permission fix)mref. 1. Copyright 1970 Academic Press)... 

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