Barriers energy absorbing

A nucleus can acquire the necessary excitation energy to overcome this barrier by absorbing either a nuclear particle or electromagnetic... 

Civil engineering uses include large diameter pipe for culverts and air ducts and energy-absorbing highway safety devices such as crash barriers filled with polyurethane foam and barrels filled with sand installed around bridge abutments. On a more down-to-earth level, the components of portable privies are frequently rotationally molded. 

The interfacial barrier theory is illustrated in Fig. 15A. Since transport does not control the dissolution rate, the solute concentration falls precipitously from the surface value, cs, to the bulk value, cb, over an infinitesimal distance. The interfacial barrier model is probably applicable when the dissolution rate is limited by a condensed film absorbed at the solid-liquid interface this gives rise to a high activation energy barrier to the surface reaction, so that kR kj. Reaction-controlled dissolution is somewhat rare for organic compounds. Examples include the dissolution of gallstones, which consist mostly of cholesterol,... 

The CASPT2/6-311G(2d,p) barrier for the process 2b — 3b is only ca. 3 kcal/mol, and this reaction is calculated to be exothermic by about 6 kcal/mol. These computational results are consistent with the failure of Schuster s time-resolved IR experiments to detect 2b.38b,c A barrier of 3 kcal/mol implies rapid conversion of 2b to 3b at room temperature, and a 6 kcal/mol difference in energy between 2b and 3b means that at 25°C the equilibrium would overwhelmingly favor 3b. In addition, azirine 2b probably absorbs less strongly than cyclic ketenimine 3b in the infrared, thus rendering detection of the azirine even more difficult. 

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