Stripping computer simulations

Apte, S.C., Gardner, M.J., Ravenscroft, J.E. and Turrell, JA. (1990) Examination of the range of copper complexing ligands in natural waters using a combination of cathodic stripping voltammetry and computer simulation. Anal. Chim. Acta, 235, 287-297. 

Thus this feature is extremely useful with electrolyte systems, reducing the number of computer simulations necessary to find the correct control strategy. With this design to specifications feature, FRACHEM/ECES has been used to determine a proper caustic injection rate to reduce the ammonia and hydrogen sulfide concentrations to meet EPA specifications without inordinate amounts ot stripping steam. 

The value of v, for d = 2 has also been determined by computer simulation on lattices18,19 and, by using the strip method (see Chapter 12, Section 2.4), Derrida and Saleur19 found... 

Chapter 12 Appendix. Computer Simulations for Absorption and Stripping... 

When a computer simulation is used for a distillation column, the number of liquid transfer units can be calculated for each theoretical stage in the stripping section with Equation 6.6 using the stripping factor for the light key impurity in each stage, where NTS = 1 ... 

A computer simulation for the distillation of ethanol and water shows that the second theoretical stage from the bottom would operate with a stripping factor of 3.0. How many liquid phase mass transfer units are equivalent to that theoretical stage ... 

Visual inspection is difficult to handle since the 1681 chromatograms were simulated. To overcome this problem, another use of computer simulation is the construction of contour diagrams of the two-dimensional solvent domain [44]. An example of such a diagram for the separation of a mixture of steroids was described. Good agreement was obtained between the simulated and the experimental results on a dual plate consisting of a strip of C g layer adjacent to silica gel. 

Strutwolf J, Arrigan WM (2010) Optimisation of the conditions for stripping voltammetric analysis at liquid-liquid interfaces supported at mictopote arrays a computational simulation. Anal Bioanal Chem 398 1625-1631... 

Fig. 4A-H Comparison of two different variants of FRAP strip-FRAP and FLIP-FRAP (see also Fig. 3B, C). The combined use of the two protocols may allow to discriminate between transient binding and slow diffusion. The curves are based on computer simulated FRAP experiments (see the text) A, B schematic drawings of the strip-FRAP (see also Fig. 1C) and FLIP-FRAP methods. The FLIP-FRAP method differs from the strip-FRAP in that two areas are monitored after bleaching. Briefly, a strip at one pole of the nucleus is bleached for a relatively long period at a moderate excitation intensity. Subsequently the fluorescence is monitored in that region (FRAP), but also in the area at the other side of the nucleus (FLIP). Subsequently the difference between the two (normalised) fluorescence levels is plotted against time C schematic drawing of two scenarios where molecules are either free, but relatively slow (D=4 pmVs, top panel), or relatively fast (D=7 pm /s), but transiently immobilised such that 30% is immobile in steady state and individual molecules are immobilised for 45 s (bottom panel) D, E strip-FRAP and FLIP-FRAP curves of the scenarios depicted in C. In this case strip-FRAP can discriminate between the two cases, whereas the FLIP-FRAP curves are nearly identical F schematic drawing of a situation where freely mobile molecules are slower (D=l pmVs, top panel) than in C G,H strip-FRAP curves are identical whereas the FLIP-FRAP method can now discriminate between the two scenarios...

Fig. 5A-C The effect of correction for monitor bleaching in FRAP experiments. The curves are based on computer simulated FRAP experiments (see text) A strip-FRAP curves of freely mobile (D=7 pm /s) molecules and the same of which 30% is permanently immobihsed B strip-FRAP of the same situations as in A with the difference that now a considerable monitor bleaching is simulated. This may in practice often occur when molecules are investigated at low concentration C to correct for monitor bleaching the experiments were repeated without the bleach pulse. The corrected curve fits well in a situation where the molecules are aU freely mobile. However, when an immobile fraction is present, the correction overcompensates the monitor bleaching that actually occurred. This is due to the fact that during the control experiment the immobile fraction bleaches with different kinetics than the free fraction. In the FRAP experiment, after the bleach pulse the immobile fraction is bleached and the signal will have different bleaching characteristics...

The computer simulation indicates that the maximum loading in this column occurs at the top of the stripping section. The vapor rate here is 0.975 times the overhead vapor flow, while the liquid rate is 1.675 times the reflux flow rate. The flow parameter at the top of the stripping section is ... 

The Absorption factor or Stripping factor chart, as it is sometimes known, is shown in Fig. 50.5. It provides simple calculation methods for hydrocarbons when considering either an Absorber tower or a Stripper tower in hydrocarbon service, but for combination Absorber-Stripper towers the calculation procedures become iterative and a lot more complex. So for a combination Absorber-Stripper tower it is best not to attempt to use this chart. It is actually better to resort to a computer simulation. In fact, as a point of historical interest, Norman tells me that it was when the idea of combined Absorber-Stripper towers was first invented that brought about the use of computer simulations so as to handle all the intricate and cumbersome calculations needed to design them. 

Transcrystallinity in thin strips of polymer films can be reproduced by 2D or three-dimensional (3D) computer simulations (e.g., [47, 50, 51]). Additional nuclei with a given density are simply added on the borders and the program calculates the actual shapes of semicrystalline entities (Fig. 15.10). This demonstrates the geometrical origin of pure transcrystallinity. Computer simulation was also employed to study crystallization at fiber surfaces [52-56]. 

In order to eliminate the reflection of waves from the outflow boundary, the buffer domain technique developed by Liu Liu (1994) was used in these simulations. The buffer domain, as indicated in Fig. 2.30, is a narrow strip of the computational domain adjacent to the outflow boundary. A continuous buffer function b ) was introduced (in Eqns. (2.7.15) and (2.7.16)) which has a value of one in the main computational domain that decreased monotonically in the buffer domain to zero at the outflow boundary. To treat growing or unstable modes, a second buffer function bReiO was used (in Eqn. (2.7.16)) to gradually reduce the Reynolds number in the buffer domain to a value below the critical Reynolds number. The used buffer functions b ) and bfi iO re as given in Liu Liu (1994). 

First of all, let us discuss the case of equal concentrations nA(t) = nB(t) = n t) when two kinds of similar correlation functions coincide Xjj r,t) = X r,t), u = A,B. In Fig. 5.2 the concentration development in the one-dimensional case is presented [26]. The curve (a) gives averaged (over 10 simulations) computer-calculated density. Stripped lines demonstrate dispersion of results they correspond to the curves n t)) s t), where ( (0) is standard deviation. Curve (b) shows the numerical solution of a set (4.1.19), (4.1.28), and (5.1.14) to (5.1.16) derived in the framework of the superposition approximation. Curve (c) gives results of the linear approximation (4.1.41) and (4.1.42). At last, the additional curve (d) is drawn Just to illustrate concentration behaviour at short times. In the linear approximation we neglect similar reactant correlation, X r,t) — 1, whereas in curve (d) dissimilar (AB) reactant correlations (4.1.40) are also... 

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