Trigger mechanism, homogeneous

Extensive laboratory-scale studies have been conducted to investigate the triggering mechanism for RPTs when LNG, liquefied petroleum gas (LPG), and liquid refrigerants contact a hot liquid (usually water). These studies are covered in Sections III and VII. The evidence seems overwhelming that RPTs in these cases result from superheating of the cold, volatile liquid to its superheat-limit temperature where prompt homogeneous nucleation occurs in a time period of a few microseconds. (The properties of a superheated liquid and the concept of homogeneous nucleation are reviewed briefly in Section IX.)... 

The mechanical deformation under electrical stimulation is much smaller than under chemical stimulation. Under electrical stimulation, an unsymmetrical distribution of the concentrations and thus of the osmotic pressure difference leads to an unsymmetrical deformation. It can be seen that the chemical stimulation triggers a homogeneous swelling of the gel film, while the electrical stimulation leads to an... 

More complicated reactions that combine competition between first- and second-order reactions with ECE-DISP processes are treated in detail in Section 6.2.8. The results of these theoretical treatments are used to analyze the mechanism of carbon dioxide reduction (Section 2.5.4) and the question of Fl-atom transfer vs. electron + proton transfer (Section 2.5.5). A treatment very similar to the latter case has also been used to treat the preparative-scale results in electrochemically triggered SrnI substitution reactions (Section 2.5.6). From this large range of treated reaction schemes and experimental illustrations, one may address with little adaptation any type of reaction scheme that associates electrode electron transfers and homogeneous reactions. 

The medium subjected to cavitation may be a macroscopically homogeneous liquid (before cavitation occurs),or a heterogeneous medium made of immiscible liquids or a solid and a liquid. Any liquid can be subjected to cavitation, which a priori can be triggered by any kind of pressure wave, from infrasonic frequencies up to several MHz. For example, bromine atoms released in brominated water cavitating at infrasonic frequency (<16 Hz) convert maleic to fumaric acid via a mechanism described in Ch. 2 (p. 65). Sonoluminescence, usually observed between 20 kHz and 2 MHz (Fig. 1), was also studied by... 

Delighted by the unique features of (NHC)platinum(dvtms) complexes 15, it was decided to investigate in detail the mechanism of the hydrosilylation triggered by these catalysts. Prior to these studies, several research groups had already demonstrated the homogeneous nature of the active platinum species in... 

It is important to notice that the five models proposed so far imply different mechanisms for earthquake occurrence. All but Poisson model are applied to mark the occurrence of large earthquakes on faults, while the Poisson model can also be used to model the seismicity into homogeneous seismotectonic zonation, where each single zone includes several faults. Trigger models described in the next section are applied on extended areas, where the interaction among faults plays an important role and the clustering of the seismicity is the main feature in... 

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