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Freezing volume changes

The structure of residual austenite is metastable, during exploitation it may panially transform into bainite, whereas during quenching this transformation may be caused by the freezing out processing. The transformation of residual austenite into bainite is connected with volume change, whereas diminishing the content of austenite in martensite by 1% causes a 0,07% increase of its volume. [Pg.18]

Melting, a major physical event, has small, subtle effects on shock-compression wave profiles. The relatively small volume changes and limited mixed-phase regions result in modest, localized changes in loading wave speed. Consequently, shock-induced melting and freezing remains an area with little data and virtually no information on the influence of solid properties and defects on its kinetics. [Pg.46]

Only a few materials fit into this category they seldom can be categorized into one of the above material classes. Water fits into the category of materials with unusual behavior. Water is one of the few materials that expands upon freezing. It changes volume by approximately 8% transiting from the liquid to the solid state. [Pg.1485]

We could face two limiting situations an inconveniently slow reaction [15] and a process that is too fast to monitor [ 16]. One may choose to run experiments at a higher temperature for reactions that are too slow at around the usual 298 K. In this case, a limitation is imposed by the boiling point and vapour pressure of the solvent which may lead to evaporation and, consequently, volume change (see above). On the other hand, it may be necessary to carry out studies at low temperatures if the reaction is too fast at 298 K. In this case, potential problems include solutions freezing and condensation of atmospheric water vapour on the reaction vessel and optical surfaces, which may affect spectrophotometric measurements. [Pg.61]

Nucleation of a new phase in the solid state is more complicated than that of nucleation in freezing. Volume difference between the new and old phases causes an elastic misfit term that increases AG. Destruction of existing grain boundaries reduces AG. An expression for the free energy change during nucleation of 3 in a matrix of a is... [Pg.104]

An intriguing possibility we raise here for the first time is that there must be particular brine compositions where the net volume change during freezing is zero. That is, the combined effects of ice expansion and contraction effects due to salt precipitation and brine compositional migration toward a more salt-rich residual brine all average out to zero net volume change. [Pg.85]

Since we are dealing with a freezing-point change, we must know the molality of the solution, and we can use any volume of solution for the calculations—using 1 L is convenient. [Pg.290]

Table 1-7 Volume Change of Water and Sucrose Solutions on Freezing... Table 1-7 Volume Change of Water and Sucrose Solutions on Freezing...
Table 1-8 Expansion of Fruit Products During Freezing Volume Increase During Temperature Change from Product 70 °F to OF (%) ... Table 1-8 Expansion of Fruit Products During Freezing Volume Increase During Temperature Change from Product 70 °F to OF (%) ...
Infiltration of the permeable concrete with molten sulfur yields a matrix which is almost impermeable to water. The freeze-thaw durability tests have indicated this is so, and immersion tests showed that fully infiltrated specimens absorbed less than 0.3% water by volume over several months, although methanol immersion and vacuum poro-simeter measurements revealed that a pososity of over 5% was available for filling. A total shrinkage of about 13% (Table I) occurs when liquid sulfur crystallizes to the stable low-temperature S< form, but much of the volume change appears to be accommodated in closed pores and intercrystal inversion fractures which affect the permeability little. [Pg.93]


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See also in sourсe #XX -- [ Pg.13 , Pg.272 , Pg.273 ]




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