Quasi-steady-state regime

At low frequencies, it approaches the macroelectrode behaviour. Indeed the steady-state solution shows that the microelectrode can be considered as a simple extension of the macroelectrode. In this quasi steady-state regime, the frequency is small enough to allow the concentration wave to propagate over the whole diffusion layer thickness. 

In the first of these equations each of the two terms in parentheses vanishes since, when the quasi-steady-state regime holds, the set relations (A7) must remain independent of the actual values of di and 2- The five algebraic relations obtained from (A7), plus the four kinetic equations for the slow variables in (A6), correspond to the nine degrees of freedom of the initial system (Al). 

From Equation 7.80 it is seen that the vacancy flux always exists at any dependence Ey (r). So, vacancy segregation cannot represent the reason for the stability of a hollow nanoshell. The delay can be connected only with the time of attainment of the quasi-steady state regime. But, evidently, the vacancy segregation in the nanoshell cannot present anything special, since similar segregation must take place in macroscopic samples (for example, at sintering of powder mixtures) and, as far as it is known, it in no way prevents, say, void coalescence. 

Rheology in general addresses the response of materials to stresses applied in various ways. The main principle of rheology is the description of the mechanical properties of systans using simple idealized models containing a relatively small number of parameters. The simplest approach is the so-called quasi-steady-state regime, which involves a restriction on uniform shear and low deformation rates. 

Stage II is the quasi-steady-state nucleation regime. During this period, the distribution of clusters has built up into a quasi-steady state and stable nuclei are being produced at a constant rate. 

The existence of the (quasi) steady-state in the model of particle accumulation (particle creation corresponds to the reaction reversibility) makes its analogy with dense gases or liquids quite convincing. However, it is also useful to treat the possibility of the pattern formation in the A + B —> 0 reaction without particle source. Indeed, the formation of the domain structure here in the diffusion-controlled regime was also clearly demonstrated [17]. Similar patterns of the spatial distributions were observed for the irreversible reactions between immobile particles - Fig. 1.20 [25] and Fig. 1.21 [26] when the long range (tunnelling) recombination takes place (recombination rate a(r) exponentially depends on the relative distance r and could... 

Quasi-steady-state periodic regime (T Tj. The input variable varies rather slowly compared to the dynamics of the system, and the system follows the input variable almost exactly. The time-averaged performance of the reactor is calculated applying the quasi-steady-state approximation to the state of the system and averaging out the resulting performances at any time. 

The explosion limit phenomenology observed in hydrogen-oxygen mixtures has been semi-quantitatively described in section 2.1.2. For an initial pressure below approximately one atmosphere there exists one threshold temperature for explosion, typically between 700 and 900 K, whose magnitude is determined by the appropriate isothermal branched chain kinetics. More specifically, this boundary, separating regimes of slow, quasi-steady state and explosively rapid reaction, is defined by an equality between the rates of chain centre formation by branching steps and destruction by termination steps. 

The example of temporal behavior of a single-route catalytic reaction shows promising results. Apparently, many results obtained for single-route two-step catalytic reactions can be transferred into results for single-route reactions with a linear mechanism under the assumption of a quasi-steady-state kinetic regime regarding the surface intermediates. 

Amatore C, Pebay C, Sella C, Thouin L (2012) Mass transport at microband electrodes transient, quasi-steady-state, and convective regimes. Chem Phys Chem 13 1562-1568... 

It is the occurrence of a fast steady-state branched-chain reaction that enables to realize a noncatalytic gas-phase process and create a stationary technological process on its basis. The quasi-steady-state branched-chain mode provides a high rate of a noncatalytic reaction at relatively low temperatures, whereas the absence of a solid phase (catalyst) minimizes the influence of heterogeneous processes, which lead to the formation of deep oxidation products. In addition to the critical transition between the oxidation modes, other manifestations of the nonlinear nature of the process, such as cool flames, NTC region, reaction rate temperature hysteresis, and oscillatory regimes, have been observed. 

J. Relaxed steady-state or sliding regime (T rj. When the input varies rapidly relative to the characteristic response time, the state oscillates with a very small amplitude. The quasi-steady-stale approximation can be applied to the state using the time-averaged value of the control. The performance of the system can be predicted using the performance in comparable steady-state operation. 

The equations governing the fluid motion and heat transfer in these quasi-steady regimes are (if the property values and boundary conditions are the same) identical to those for steady-state convection in the same geometry with a uniform internal generation of energy [73]. The heat transfer equations from one situation can therefore be readily transferred to the other by replacing the constant pcp dT/dt by the internal generation rate q " (in W/m3 or Btu/h-ft3). 

In an effort to analyze Problem 11-21 in more detail, you focus on the instantaneous rate of interphase mass transfer across a high-shear no-slip interface at axial position z within the column and construct the following quasi-macroscopic steady-state mass balance on mobile component A in the liquid phase. The flow regime is laminar and the size of the liquid-phase control volume, CV, is pJr(/ coiumn) dz. ... 

In the quasi-steady regime, the time derivative of P is lower order, and from the analysis of the full problem we see that Cj = 0(1), which implies that the phase change is a lower-order effect in the two-phase region, away from the boundary layer. It follows that at steady-state the vapor flux carried by the saturated gas is constant and given by the terms within the z derivative, specifieally,... 

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