Combined with digital simulation

The convolution-deconvolution voltammetry, combined with digital simulation techniques, was applied [36] to determine the electrochemical and chemical parameters for the Cd(II)/Cd(Hg) system in aqueous NaNOs solution. The agreement between experimental and theoretical data indicated that the reduction mechanism at the mercury electrode proceeds via consisting in chemical step (C) followed by charge transfer step (E)-so-called CE mechanism [37]. 

In Fig. 6 is shown a series of cyclic voltammograms which demonstrate that the catalytic properties of the the complex are due to chemistry that originates from the second bpy-based reduction wave. Using bulk electrolysis and cyclic voltammetry techniques combined with digital simulation methods, the following mechanism can be proposed for electrocatalytic CO production in CH CN... 

The waste minimisation reaction related examples in this text are represented mainly by combinations of consecutive and parallel type reactions. Although the major details of such problems are dealt with in conventional textbooks, it may be useful to consider the main aspects of such problems from the viewpoint of solution by digital simulation. 

Understanding the development of SPICE is useful in making a worthwhile comparison of vendor-offered simulation software. The foundation of many vender-offered simulators is Berkeley SPICE 3F.5 combined with XSPICE from the Georgia Institute of Technology. XSPICE is an add-on to SPICE 3, enhancing it with several key features, including a mixed-mode simulation capability (true digital simulator) and over 40 new primitive functional blocks such as Laplace and state machine elements. 

Any discussion of the digital simulation of problems involving diffusion begins with a consideration of the combined form of Fick s laws [5],... 

The real power of digital simulation techniques lies in their ability to predict current-potential-time relationships when the reactants or products of an electrode reaction participate in some intervening chemical reaction. These kinetic complications often result in a fairly difficult differential equation (when combined with the conditions for diffusion or convection encountered in electrochemical problems) that resists solution by ordinary means. Through simulation, however, the effect of any number of chemical steps may be predicted. In practice, it is best to limit these predictions to cases where the reactants and products participate in one or two rate-determining steps each independent step adds another dimensionless kinetics parameter that must be varied over the range of... 

For consecutive or parallel electrode reactions it is logical to construct circuits based on the Randles circuit, but with more components. Figure 11.16 shows a simulation of a two-step electrode reaction, with strongly adsorbed intermediate, in the absence of mass transport control. When the combinations are more complex it is indispensable to resort to digital simulation so that the values of the components in the simulation can be optimized, generally using a non-linear least squares method (complex non-linear least squares fitting). 

Already in the mid-1960s, there was rich potential of applying such experiments to the determination of concentrations but even more to the elucidation of reaction mechanisms and kinetics coupled to electron transfer at an electrode was recognized. Today the resulting Knear sweep or cyclic voltammetries are employed as simple, flexible routine techniques in particular as sophisticated means to solve chemical and mechanistic problems. The combination with computer control, ultramicroelectrodes, and digital simulation has further contributed to their success. 

Britz D, Stmtwolf J (2000) Higher-order spatial discretisations in electrochemical digital simulation. 1. Combination with the BDF algorithm. Comput Chem 24 673-684... 

Stmtwolf J, Britz D (2001) Use of high-order discretisations in digital simulation. 2. Combination with the extrapolation algorithm. Comput Chem 25 511-520... 

Britz D, 0sterby O, Stmtwolf J, Svennesen TK (2002) High-order spatial discretisations in electrochemical digital simulations. 3. Combination with the explicit Runge-Kutta algorithm. Comput Chem 26 97-103... 

The mechanism of the oxidation of 2-mercapto-5-methyl-l,3,4-thiadiazole (McMT) to its disulfide dimer and its subsequent reduction was examined with a combined approach employing experimental data and digital simulation. To elucidate the influence of proton transfers on these redox processes, special attention was paid to the influence of various bases and proton donors on both the oxidation and reduction reactions. In particular, McMT oxidation is facilitated by a rapid bimolecular proton transfer from McMT to weak bases such as pyridine that produces McMT , the thiol-ate form, which is then oxidized. There is no such facilitation in the presence of the sterically hindered base 2,6-di-r-butylpyridine, suggesting that the facilitation occurs through the formation of a discrete hydrogen-bonded complex/ ... 

Using advances in computer reconstruction methods (see e.g. Kikkinides and Burganos, 2000 Torquato, 2001) and past experience with discrete particle deposit simulations (Konstandopoulos, 2000), we have developed algorithmic as well as process-based reconstruction techniques to generate three-dimensional (3D) digital materials that are faithful representations of DPF microstructures. We refer to this approach as DPF microflow simulation (MicroFlowS). MicroFlowS is thus a short name for a computational approach, which combines... 

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