Electro-chemical reaction

Figure 56 uses the example of associate formation between the ionic defect O and the electronic defect h to emphasize that the strict treatment requires the solution of coupled diffusion-reaction relationships, describing the general (electro-)chemical reaction scheme with individual diffusion or rate constants as parameters (cf. Section VI. 2). Source terms (q) must be taken into account in the relevant continuity equations, e.g., for defect B that can be created by... 

The ene- pe chlorination, specific with this halogen atom, of alkenes would account for a somewhat different mode of halogen addition, giving usefiil allylic dilorides. Efficient and convenient reagents and methods develtqted are dichlorine monoxide (ChO equation 36), r-butyl hypochlorite, and electro-chemical reactions with chloride ion (equation 37). The ene-type chlorination proceeds smoothly with... 

The galvanic cells produce electric energy via electro-chemical reactions, while electrolytic cells, such as those used in water electrolysis, are electrochemical cells in which a chemical reaction is forced by added electric energy. 

Corrosion Damaging or modifying of (usually) metal materials in the surface area by chemical or electro-chemical reactions. 

The diversity of the (electro)chemical reactions coupled with a main process can be classified as... 

Corrosion of metallic materials takes place via an electro-chemical reaction at a specific corrosion rate. Consequently, the life of a metallic material in a particular corrosive environment can be accurately predicted. This is not the case with polymeric materials. 

The electro-chemical reactions are assumed to take place in the fluid phase. The explicit introduction of the occupation numbers (0,-, S,- 0,- = 1) as variables is a natural description of the possible lack of catalytic sites and methanol cross over effects. Due to the use of expensive catalysts, electrochemical saturation effects may be reached by fuel cells in some... 

The electrochemical gradient is the driving force for the response of the system to re-establish the electrochemical equilibrium that will involve an interplay of mass transport, (electro)chemical reactions and external forces. 

As the chemical constitution of the participants in the equilibrium, the overall electro-chemical reaction and its changes dependent on pH are completely unknown in the majority of cases, the values are either related to pH = 0 (Eqo) or to pH 7 (Eq/) and the stoichiometric factor is set at... 

The effect of liquid surfactants can powerfully accelerate stress crack formation. Nevertheless, stress crack formation in plastics must be distinguished from stress crack corrosion as known in particular in metallic materials. Corrosion is understood as the erosion of atoms from the material by chemical processes and in metals particularly by electro-chemical reactions. Additional influence by stresses leads to crack formation and brittle fracture which often resembles of the failure of stress cracks in plastics. Stress crack formation in thermoplastics is, however, a purely physical process. No chemical changes take place in the material even under the influence of surfactants. The terminology is nevertheless not completely uniform. The accelerating effect of liquids on stress crack formation in plastics is occasionally described as stress crack corrosion although no real corrosion process is connected with it. 

Chemical species present in the fuel cell can further deactivate the catalyst, either through surface poising or by (electro)chemical reactions, which drastically modify the catalyst. Such chemical species are then called contaminants, they can have their source outside as well as inside the system. 

The (electro-)chemical reaction among precursor liquids on immersed substrates. 

Major PEM fuel cell contaminants, their sources, and their chemical/electro-chemical reactions were reviewed in this chapter. The key contaminants and their principal sources are summarized in Table 2.2 [150]. 

In case of the interaction of a solid with active medium, it may lead both to plasticity increase and to its reduction (accompanied by hardening), depending on the results of surface chemical (electrochemical) reactions. E. M. Gutman has discovered in 1967 that (electro)chemical reactions on the surface of a stressed solid cause additional dislocation flux, which changes... 

Corrosion of steel in concrete is probably the most serious durability problem of reinforced concrete in modem times, and therefore, a clear understanding of the phenomenon is of cmcial importance. The phenomenon itself is an electro-chemical reaction. In its simplest form, corrosion may be described as a current flow from anodic to cathodic sites in the presence of oxygen and water. This is represented by the following equations ... 

In the absence of (electro)chemical reactions at the substrate, the solution of a set of equations (Equation 19.4) gives the access to electrical properties of the pipette and the liquid droplet (meniscus) between the probe and the substrate. This is essential for modeling the overall... 

Furthermore, although in this chapter we will mainly deal with photoluminescence (i.e., luminescence arising from an excited state created by the absorption of light), it is important to underline at this point that (electro-)chemiluminescence (luminescence arising from an excited state generated by an (electro-)chemical reaction), has made analytical potentials even stronger. 

Charlot, G., Badoz-Lambling, J., and Tremillon, B., Electro-chemical Reactions, Elsevier, Amsterdam, (1962). 

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