Studies of freezing-melting hysteresis in cryoporometry scanning loop experiments using NMR diffusometry and relaxometry
Hitchcock, I., Holt, E. M., Lowe, J. P. and Rigby, S. P., 2011. Studies of freezing-melting hysteresis in cryoporometry scanning loop experiments using NMR diffusometry and relaxometry. Chemical Engineering Science, 66 (4), pp. 582-592.
Related documents:This repository does not currently have the full-text of this item.
You may be able to access a copy if URLs are provided below. (Contact Author)
Theories of freeze-thaw hysteresis in NMR cryoporometry of disordered mesoporous solids have been rigorously tested using scanning loop experiments together with concurrently obtained (PFG) NMR diffusometry and relaxometry data. PFG-NMR and relaxometry have revealed that the spatial disposition of frozen and molten phases, at a particular point in a loop, depends upon the prior thermal history, as expected from previous work. However, these data have also shown the vital importance of incorporating the advanced melting process in order to adequately interpret cryoporometry data, and thence the ability to distinguish between interpretations arising from structural or thermodynamic considerations. The advanced melting process has been shown to greatly impact the accuracy of pore size distributions derived from the melting curve using the conventional approach that neglects it. Further, it has been shown that the freeze/thaw hysteresis can be progressively expunged using 'mini-loop'-type experiments. Hence, the potential reversibility of freeze/thaw processes, even in disordered materials, has been demonstrated. This lack of hysteresis is consistent with the axial freezing and melting expected when both heterogeneous nucleation of freezing, and advanced melting, occur.
|Creators||Hitchcock, I., Holt, E. M., Lowe, J. P. and Rigby, S. P.|
|Departments||Faculty of Engineering & Design > Chemical Engineering|
Faculty of Science > Chemistry
Actions (login required)