Temperature dependence Ohmic model

Bv employing a soluble cationic polymer as the solution electrolyte polymer films can be sterical ly blocked from reducing beyond the formal zero valent form. In the zero-valent form the polymer is an ohmic conductor both in solution and dry. A model has been proposed which describes the conductivity of the polymer and in part accounts for its ohmic nature and semi conductor-1 ike temperature dependence. 

Two essential features of the sliding CDW mode seem to be rather well established for the SDW mode, too. Non-ohmic electrical transport sets in above a finite threshold field, and a collective mode contribution is evident at finite frequencies in the spin-density wave ground state. These features are also in qualitative agreement with theoretical models. However, important differences are observed, like the temperature dependence of the threshold field and the relaxation time and effective mass of the collective mode. Further experiments are required to establish details of this behaviour, as well as to search for other nonlinear effects,like broad and narrow-band noise, hysteresis and memory effects etc. 

Partial pressures (normalized to atmospheric pressure) depend on anode/cathode gas pressure and composition while standard potential and ohmic impedance are both temperature dependent. Fuel cell polarization losses are generally dependent on partial pressures, temperature, and current density, and are spatially distributed in an actual cell. In this paper the dynamic model is lumped parameter, where outlet properties are equal to average properties (Ding et al, 1997 Lukas et al, 1999 Lukas et al, 2001). 

The macroscopic modeling described for the PEMFCs can also be apphed to the case of an SOFC fed with hydrogen if we have tests which enable us to identify the different parameters. The activation overvoltage term is far smaller in the case of an SOFC. In fact, the open circuit voltage of a cell is nearest to the reversible potential of the cell. Because of the high temperature, all the species are in gaseous form, and their activity is equal to their partial pressure. The Ohmic resistance of the MEA (the electrodes and the membrane) is highly dependent on the temperature. 

---