Overlapping stages

The setting and hardening reactions are first outlined in general terms. They can be considered to take place in a number of overlapping stages. 

The following account is based mainly on the studies of Wilson and coworkers, with some re-interpretation of experimental data. The composition of the cement used is given in Table 6.9. In brief, the reaction takes place in several overlapping stages extraction of ions from the glass, migration of cations into the aqueous phase, precipitation of insoluble salts as pH increases, leading to formation of an aluminium phosphate gel. 

The alteration and mineralization in the amli deposit is result of a series of 3 overlapping stages (Fig. 2) The pre-ore... 

Combining particulate fillers, such as carbon black, into thermoplastics involves the following sequential,but to some extent, overlapping stages [83] ... 

As is the case for most natural phenomena, oxide films often have a rapid initiation, a vigorous youthful growth period, a fruitful middle age, a declining later period and, finally, destruction. In this vein, we can list at least ten overlapping stages which may characterize an oxide film at one time or another during its lifetime. 

In situations where there is overlap between the occurrence domains of two or more polymorphs the moditications may appear simultaneously or in overlapping stages so that a particular procedure or process yields more than one form under identical conditions. This phenomenon is termed concomitant polymorphism and has been treated in considerable detail in a recent review (Bernstein et al. 1999). 

The thermal decompositions of nickel(II)-cobalt(II) oxalate solid solutions were studied using TG and TM [103], A series of the mixed binary Ni(II)-Co(II) oxalate samples was prepared at 25% (atom) intervals across the system. Physical mixtures were also prepared by mixing the pure end members. The DTG and DTM curves showed that the decomposition proceeds to completion in two overlapping stages. The kinetics of the individual steps were not studied. From the DTG curves, the authors stated that the physical mixtures behaved as individual oxalates, while the coprecipitate decomposed as a single entity. The TM curves showed that the products formed from the physical mixture and the coprecipitate were distinctly different. The magnetic behaviour of the product from the coprecipitate was consistent with the behaviour predicted for a Ni-Co alloy, but the products from the physically mixed oxalate do not show the transition temperature predicted for an alloy. The kinetics of decomposition of iron-nickel mixed oxalates have been studied by Doremieux et al. [104]. 

The development of carcinogenesis in a mammalian cell may be represented by three discrete but often overlapping stages, inclusive of the initiation, promotion, and progression phases [65], 12-0-... 

Two overlapping stages were detected in the thermal decomposition of anomerlc glycopyranosides at 200-300°, cleavage of the glycosidic bonds occurs with intramolecular and intermolecular... 

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