Любопытно, что авторы запатентовали (http://www.sfu.ca/physics/ugrad/courses/teaching_resources/demoindex/thermal/th4c/patentheatpack.html) в 1978 году устройство таких грелок, сами не полностью понимая процесс, происходящий в щелях металлического диска. Вот цитата:
It is not presently fully understood how the activator strip 16 initiates crystallization of the supercooled sodium acetate solution; however, it is believed that flexing produces minute continuances or extensions of fracturing at the blind ends 24 of the fissures 20 and that these new fractures are instrumental in initiating crystallization. If this belief is correct, these extensions are extremely small since an activator strip can be used hundreds of times without breaking.
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Date: 2005-12-09 10:27 pm (UTC)It is not presently fully understood how the activator strip 16 initiates crystallization of the supercooled sodium acetate solution; however, it is believed that flexing produces minute continuances or extensions of fracturing at the blind ends 24 of the fissures 20 and that these new fractures are instrumental in initiating crystallization. If this belief is correct, these extensions are extremely small since an activator strip can be used hundreds of times without breaking.