Conductivity dependent

The glass-transition temperature, T, of dry polyester is approximately 70°C and is slightly reduced ia water. The glass-transitioa temperatures of copolyesters are affected by both the amouat and chemical nature of the comonomer (32,47). Other thermal properties, including heat capacity and thermal conductivity, depend on the state of the polymer and are summarized ia Table 2. 

Other methods attempt to probe the stmcture of the foam indirectly, without directly imaging it. Eor example, since the Hquid portion of the foam typically contains electrolytes, it conducts electrical current, and much work has been done on relating the electrical conductivity of a foam to its Hquid content, both experimentally (15) and theoretically (16). The value of the conductivity depends in a very complex fashion on not only the Hquid content and its distribution between films and borders, but the geometrical stmcture of the bubble packing arrangement. Thus electrical measurements offer only a rather cmde probe of the gas Hquid ratio, a quantity that can be accurately estimated from the foam s mass density. 

Polypyrroles. Highly stable, flexible films of polypyrrole ate obtained by electrolytic oxidation of the appropriate pyrrole monomers (46). The films are not affected by air and can be heated to 250°C with Htde effect. It is beheved that the pyrrole units remain intact and that linking is by the a-carbons. Copolymerization of pyrrole with /V-methy1pyrro1e yields compositions of varying electrical conductivity, depending on the monomer ratio. Conductivities as high as 10 /(n-m) have been reported (47) (see Electrically conductive polymers). 

Thermal Conductivity. The refractory thermal conductivity depends on the chemical and mineral composition of the material and increases with decreasing porosity. The thermal conductivities of some common refractories are shown in Figure 2. 

The commercially important anatase and mtile both have tetragonal stmctures consequentiy, the values of physical properties such as refractive index and electrical conductivity depend on whether these are being measured parallel or perpendicular to the principal, ie, axis. However, in most appHcations, this distinction is lost because of random orientation of a large number of small crystals. It is thus the mean value that is significant. Representative physical properties are coUected in. Table 6. 

Both anatase and mtile are broad band gap semiconductors iu which a fiUed valence band, derived from the O 2p orbitals, is separated from an empty conduction band, derived from the Ti >d orbitals, by a band gap of ca 3 eV. Consequendy the electrical conductivity depends critically on the presence of impurities and defects such as oxygen vacancies (7). For very pure thin films, prepared by vacuum evaporation of titanium metal and then oxidation, conductivities of 10 S/cm have been reported. For both siugle-crystal and ceramic samples, the electrical conductivity depends on both the state of reduction of the and on dopant levels. At 300 K, a maximum conductivity of 1 S/cm has been reported at an oxygen deficiency of... 

Specific Conductance. The specific conductance depends on the total concentration of the dissolved ioni2ed substances, ie, the ionic strength of a water sample. It is an expression of the abiUty of the water to conduct an electric current. Freshly distilled water has a conductance of 0.5—2 ]lS/cm, whereas that of potable water generally is 50—1500 ]lS/cm. The conductivity of a water sample is measured by means of an a-c Wheatstone-bridge circuit with a null indicator and a conductance cell. Each cell has an associated constant which, when multiphed by the conductance, yields the specific conductance. 

Copper and its alloys also have relatively good thermal conductivity, which accounts for thek appHcation where heat removal is important, such as for heat sinks, condensers, and heat exchanger tubes (see Heatexchangetechnology). Thermal conductivity and electrical conductivity depend similarly on composition primarily because the conduction electrons carry some of the thermal energy. 

Frequently, the transport coefficients, such as diffusion coefficient orthermal conductivity, depend on the dependent variable, concentration, or temperature, respectively. Then the differential equation might look Bke... 

Permeability is normally determined using linear flow in the incompressible or compressible form, depending on whether a liquid or gas is used as the flowing fluid. The volumetric flowrate Q (or Q ,) is determined at several pressure drops. Q (or Q ,) is plotted versus the average pressure p . The slope of this line will yield the fluid conductivity K or, if the fluid density and viscosity are known, it provides the intrinsic permeability k. For gases, the fluid conductivity depends on pressure, so that... 

For highly ordered 3D systems, Terril et al. showed that the electron-hopping conductivity depends on the activation energy of the electron transfer and the electronic coupling term [3 [71]. They took the latter as a... 

For molybdenite concentrates hydroxy ions must be added to maintain a near neutral pH value. The pH value at which the electroleaching of other metal sulfides is conducted depends upon the amount of hydroxy ions added. For example, when a low grade cinnabar ore is treated, the pH remains almost neutral because of the calcite content of the ore. This is also true of carbonaceous gold ores. 

The discussion becomes different when restricted to dilute solutions. In this case one must arrive at the conclusion which essentially helps to simplify the phenomena In a dilute solution the conductivity depends (besides on the number of dissolved molecules) only on the transported components being independent of their mutual associations. Thus, the more the number of water molecules prevails over those of the electrolyte the more pronounced is the influence exerted by the water molecules on the ions and the less their mutual friction. 

The prevalent receptor model for the excitatory amino acid is a tetrameric complex. As mentioned in the text, there is evidence that the channel conductance depends on the number of subunits that bind a ligand. Estimate the EC50 value and Hill coefficient for a dose-response curve assuming that the occupation at each subunit has a Kd value of 1 pi I, an % of 1, and that activation induces a transition to an active state independent of the state of the other subunits ... 

A classic case is an EC of a faradic type in which an electrode is comprised of Ni(OH)2, MnOOH, etc. active materials. Since in these chemistries the conductivity depends on electrode state-of-charge charge level, they require presence of additional stable conductive skeletons in their structure. Noteworthy mentioning that besides traditional forms of carbon or other conductors that may form such a skeleton, the latest progressive investigations demonstrate the possibility of application of different nanostructured forms of carbon, such as single-wall and multi-wall carbon nanotubes [4, 5], Yet, for the industrial application, highly conductive carbon powders, fibers and metal powders dominate at present. 

However, it has recently been shown that the conductivity depends on the presence of oxygen, indicating ionization of the peroxide rather than the ethane.29 The reader will perhaps be surprised that it has also... 

Numerical experiments have shown that in many one dimensional systems with total momentum conservation, the heat conduction does not obey the Fourier law and the heat conductivity depends on the system size. For example, in the so-called FPU model, k IP, with (3 = 2/5, and if the transverse motion is introduced, / = 1/3. Moreover, in the billiard gas channels (with conserved total momentum), the value of P differs from model to model(Li and Wang, 2003). The question is whether one can relate / to the dynamical and statistical properties of the system. 

Pure stoichiometric ceria is not a good oxygen ion conductor. The oxygen ion conductivity can be introduced dramatically by low valance doping. Thus the conductivity depends on the characteristics of the dopant elements and their concentrations. 

The electronic conductivity depends significantly on the preparation and crystalline structure of the LSM specimen. Li et al. [7] prepared LSM samples by conventional sintering and plasma spraying. Depending on the composition, the electronic conductivity of the sintered sample is between 40 and 485 Scm 1 at 1,000°C and that of plasma-sprayed coatings between 50 and 201 Scm . The electronic conductivity of the plasma-sprayed samples is 50% lower than that of the sintered sample. On an... 

Our experiments, such as those shown in Figures 9 and 10, showed that the conductivity is concentration- and temperature-reversible, i.e., that the systems are in equilibrium. Since for both the tert-butyl and the polymer solutions the conductivity depends rectilinearly on the concentration, the electrolyte must be involved in an equilibrium in which n molecules generate n ions [26, 37], in these systems most probably n = 2, and the equilibrium is, therefore, of the type... 

Carbon nanotubes can have one, two, or many sidewalls and are referred to as single-, double-, or multi-walled nanotubes (SWNT, DWNT, or MWNT). Nanotubes can be metallic, or semi-conducting depending on the chirality of the tube. Single-walled nanotubes (SWNT) are about 1 nm in diameter, and hundreds of nanometers long, whereas multi-walled nanotubes (MWNT) are like nested... 

In this section, we describe the role of fhe specific membrane environment on proton transport. As we have already seen in previous sections, it is insufficient to consider the membrane as an inert container for water pathways. The membrane conductivity depends on the distribution of water and the coupled dynamics of wafer molecules and protons af multiple scales. In order to rationalize structural effects on proton conductivity, one needs to take into account explicit polymer-water interactions at molecular scale and phenomena at polymer-water interfaces and in wafer-filled pores at mesoscopic scale, as well as the statistical geometry and percolation effects of the phase-segregated random domains of polymer and wafer at the macroscopic scale. 

The parameter c Eqn (2.1), is capable of variation by many orders of magnitude in ionic solids. In good solid electrolytes such as Na "-alumina and RbAg4l5, all of the Na /Ag ions are potentially mobile and hence c is optimised. At the other extreme, in pure, stoichiometric salts such as NaCl, ionic conduction depends on the presence of crystal defects, whether... 

Electrical conductivity is a measure of a solution s ability to conduct electricity. The conductivity depends on the concentration of the ions present and the temperature of the solution. A standard conductivity flow cell is integrated into the instrument design. 

Conductivity depends on a number of factors including the number of density of charge carriers (number of electrons, n) and how rapidly they can move in the sample called mobility /a. 

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