Conduction plane molar

Many practical mass transfer problems involve the diffusion of a species through a plane-parallel medium that does not involve any homogeneous chemical reactions under one-dimensional steady conditions. Such mass transfer problems are analogous to the steady one-dimensioiial heat conduction problems in a plane wall with no heal generation and can be analyzed similarly. In fact, many of the relations developed in Chapter 3 can be used for mass transfer by replacing temperature by mass (or molar) fraction, thermal conductivity by pD g (or CD ), and heat flux by mass (or molar) flux (Table 14-8). 

What is the stmcture of neat ionic liquids. Even though the stmcture of liquids, such as water, has been studied for many years, the study of room-temperature ionic liquids is still in its infancy [58]. Purified [BMIM][PFj], probably the most studied IL, has been shown to be purely monophasic, with no aggregates, but to have a local stmcture [47]. Imidazolium groups are positioned in pairs with a plane-to-plane separation of 4.5 A. The stmcture of ILs is also characterized by a degree of anion-cation association. Thus, in [EMIM][NTf2] and [BP][NTf2], the self diffusion coefficients of the anions and the cations measured by pulsed-gradient spin-echo N M R are superior to the diffusion coefficients deduced from the molar conductivity, which demonstrates the existence of ion pairs which cannot contribute to the ionic conduction [53]. 

The membrane water and hydronium content, M and P, are nondimensio-nalized by the acid molar density a = 1200 moles/m. The anode and cathode vapor molar densities, and C, are nondimensionalized by the vapor saturation molar density, Csat T) this is the principal dependence of the model upon the temperature. The cathode oxygen concentration Co is nondimensionalized by the inlet oxygen concentration The external voltage, F, is nondimensionalized by the open circuit voltage Eo while the local through-plane current density I y) is nondimensionalized by h = where ao is a reference value for the membrane conductance and is the thickness of the membrane. 

Convection current Conduction current Total current Maximum a.c. current Inner Helmholtz plane Membrane partition coefficient Water molar mass... 

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