Percolation stage

From the theoretical point of view, the post percolation stage shows a good agreement between the experimental and theoretical values of log cr versus for... 

Because the percolation stage is unnecessary this galenical would be expected to give inter-laboratory results that are in closer agreement than those obtained with belladonna itself. Evaporation of the tincture should not be taken so far as 10 ml, however it should only proceed at a temperature below 70° until it cannot be continued without deposition of chlorophyll and resinous matter. 

When concentrated acids are used, the carbohydrates are recovered in high yields, but the problem of economically recovering the large quantities of acid used has not been solved. At the present state of development, the dilute acid processes, especially percolating and two-stage, appear more promising. 

Alternatively, Leung and Eichinger [51] proposed a computer simulation approach which does not assume any lattice as the classical and percolation theory. Their simulations are more realistic than lattice percolation, since spatially closer groups form bonds first and more distant groups at later stages of network formation. However, the implicitly introduced diffusion control is somewhat obscure. The effects of intramolecular reactions were more realistically quantified, and the results agree quite well with experimental observations [52,53],... 

A radically new stage of development of lateral models is related to the application of PT methodology. The term percolation was introduced by Broadbent and Hammersley [225] to describe the new class of mathematical problems connected to the analysis of infiltration of liquids or the path of an electrical current through a labyrinth of bonded and nonbonded elements. This theory has become very fashionable in various fields of physics, chemistry, and technical applications (e.g., a problem of displacement of oil from a porous medium [8,223,226,227]). The basics of this theory has been comprehensively discussed in several reviews [121,228-232] and monographs [8,233,234],... 

This one-stage scrubber worked on the principle of the percolating filter technique. 

Pseudoakuammicine is the first racemic base to be discovered in the strychnine-yohimbine series of alkaloids, and the question of its origin naturally arises. The only stage in the extraction of Picralima seeds during which racemization of akuammicine might have occurred involved prolonged percolation with hot methanol however, as already discussed, akuammicine is not racemized under these conditions but suffers a more extensive decomposition. In any event, such a racemization would necessarily involve fission of the 3,7 and 15,16 bonds, followed by a nonspecific resynthesis, which is considered to be a very unlikely possibility. It was therefore suggested that, in the plant, pseudoakuammicine is produced by a nonspecific biosynthesis this would accord with its formation from a tryptophan-phenylalanine precursor, but not from an optically pure prephenic acid derivative (40). 

At the beginning of the desorption process, some condensate is removed from the wider pores (i.e. unoccupied bonds) near the surface. As the pressure is reduced, the vapour-filled pores (occupied bonds) form clusters, which eventually extend across the particle. The stage at which a spanning cluster is formed across the particle corresponds to the percolation threshold, when the pore emptying becomes rapid. This stage corresponds to the knee of an H2 hysteresis loop. 

Borkovec et al. [59] also reported on a two-stage percolation process for the ME AOT (Aerosol OT, bis(2-ethylhexyl)sodium sulfosuccinate) system AOT-decane-water. The structural inversions were investigated using viscosity, conductivity, and electro-optical effect measurements. The viscosity results showed a characteristic profile with two maxima, which was interpreted as evidence for two symmetrical percolation processes an oil percolation on the water-rich side of the phase diagram and a water percolation process on the oil-rich side. 

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