Operating cyclic, alternating

Although the Sulfreen process is cyclic, alternating between sulfur adsorption and desorption, the use of several converters in adsorbing, desorbing, and cooling service permits continuous operation. 

Multiple desiccant beds are used in cyclic operation to dry the gas on a continuous basis. The number and arrangement of the desiccant beds may vary from two towers, adsorbing alternately, to many towers. Three separate functions or cycles must alternately be performed in each dehydrator. They are an adsorbing or gas drying cycle, a heating or regeneration cycle, and a cooling cycle. 

Tests were carried out at 25°C and at initial pH 6.9. Cultures in the liquid medium were incubated in 50 mL Falcon tubes, continuously shaked at 220 rpm. Each culture contained a fresh Pseudomonas sp. 0X1 colony in 10 mL of medium. The airlift with 10 g of pumice was sterilized at 121°C for 30 min and then housed in a sterile room. One-day culture was transferred to the reactor and, after a batch phase, liquid medium with phenol as the only carbon source was continuously fed. The reactor volume V was fixed at 0.13 L. Aerobic conditions were established sparging technical air. Under these conditions microorganism started to grow immobilized on the solid s support. When immobilized biomass approached steady state, cyclic operation of the airlift was started by alternating aerobic/anaerobic conditions. 

In the NSR process, NO are stored under lean conditions in the form of nitrites and nitrates and are reduced to nitrogen and water under rich conditions by UHCs, CO and H2 present in the exhausts or by HCs injected into the exhaust gases. Accordingly, the engine operates under cyclic conditions, by alternating long lean periods with short rich excursions. 

The hypothesis of a bifunctional mechanism involving allyl radical formation and oxygen incorporation on distinct sites is advocated by Haber et al. [147,152], This hypothesis is particularly based on experiments with Mo03, Bi203 and mechanical mixtures of these oxides, which are compared with bismuth molybdate catalysts. The reaction was carried out in cyclic operation (alternating feeds of oxygen and of propene diluted with nitrogen). The results are collected in Table 5. The authors con-... 

The general mode of operation of a cyclic batch adsorption process is illustrated in Fig. 8. In its simplest form such a process employs two adsorbent beds, each of which is alternately saturated and regenerated. During the saturation or adsorption cycle, adsorption is continued until the mass transfer zone has almost reached the bed outlet. At this point the beds are switched so that the spent bed is replaced by a freshly regenerated bed, while the more strongly absorbed species is removed from the spent bed in... 

Equatorial=e. Apical = a. 6 The identity operation causes no isomerization and does not represent a mechanism. c M=Muetterties see Ref. 78. d Alternating cyclic permutations of four elements with one fixed point. Mg=BPR (see Ref. 53). 1 Turnstile rotation (see Ref. 65) p=pair t=trio. 

As demonstrated above, the most efficient reactions in the construction of cyclic structures are those that lead to the formation of several bonds as the result of a single chemical operation. This consideration stimulated the development of an alternative version of the LHASA programs aimed at finding ways of dismantling target structures with the help of especially effective disconnec-... 

If the reactions in THF and the inclusion of dead material in block copolymers are taken into account, the balance of the evidence at present seems to support the back-biting mechanism. However, the mechanisms are not really mutually exclusive, because they both suggest an alternation between a chlorine-ended chain and a sodium-ended chain. The sodium ended-chain reacts first with the initial dichloride in the rate-determining step, and then the chlorine-ended chain reacts with the sodium surface. The difference lies in the mode of formation of the cyclic materials and the importance of any condensation reactions. Both mechanisms might be operative, although one may dominate, depending on the conditions or substituents. 

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