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There are two principal classes of phase-change material: organic (carbon-containing) materials derived either from petroleum, from plants or from animals; and salt hydrates, which generally either use natural salts from the sea or from mineral deposits or are by-products of other processes. A third class is solid to solid phase change.
In physics, chemistry, and other related fields like biology, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic states of matter : solid , liquid , and gas , and in rare cases, plasma .
The classical Stefan problem aims to describe the evolution of the boundary between two phases of a material undergoing a phase change, for example the melting of a solid, such as ice to water. This is accomplished by solving heat equations in both regions, subject to given boundary and initial conditions. At the interface between the phases ...
The glass transition of a liquid to a solid-like state may occur with either cooling or compression. [10] The transition comprises a smooth increase in the viscosity of a material by as much as 17 orders of magnitude within a temperature range of 500 K without any pronounced change in material structure. [11]
GeSbTe (germanium-antimony-tellurium or GST) is a phase-change material from the group of chalcogenide glasses used in rewritable optical discs and phase-change memory applications. Its recrystallization time is 20 nanoseconds, allowing bitrates of up to 35 Mbit /s to be written and direct overwrite capability up to 10 6 cycles.
Download as PDF; Printable version; ... Computational Fluid Dynamics for Phase Change Materials; Condensation; ... This page was last edited on 10 August 2024, ...
Certain materials, such as glass and glycerol, may harden without crystallizing; these are called amorphous solids. Amorphous materials, as well as some polymers, do not have a freezing point, as there is no abrupt phase change at any specific temperature. Instead, there is a gradual change in their viscoelastic properties over a range of ...
This violation is not a defect, rather it is the origin of the observed discontinuity in properties that distinguish liquid from vapor, and defines a first order phase transition. Figure 1: The curve is an isotherm, constant, in the --plane of a fluid that includes a phase change. The various segments of the curve are described in the text.