Dielectric relaxation time of bulk water at 136–140K, background loss and crystallization effects
Bibliographic record
Abstract
Dielectric relaxation time, tau, of ultraviscous bulk water has been determined by analyzing its loss tangent, tan delta, data, which had been measured on heating the vapor-deposited amorphous solid water and hyperquenched glassy water in our earlier studies. [Johari, Hallbrucker, and Mayer, J. Chem. Phys. 95, 2955 (1991); 97, 5851 (1992)]. As for glasses and liquids generally, the measured tan delta of water is the sum of a frequency-independent background loss and a frequency-dependent relaxational loss. A two-frequency method is provided for determining the background loss and used for obtaining the relaxational part of tan delta. After considering the structural relaxation and crystal-nuclei growth effects, tau for water has been determined. At 136+/-1 K, it is 2.5+/-0.6 s when a single relaxation time is (untenably) assumed, and 42+/-14 s when a distribution of relaxation times, a characteristic of viscous liquids, is assumed, with Davidson-Cole distribution parameter of 0.75. Structural relaxation time of approximately 70 s for water at 136 K, which was originally estimated from the DSC endotherm [Johari, Hallbrucker, and Mayer, Nature (London) 330, 552 (1987)], has been revised to approximately 33 s. Temperature dependence of tau could not be determined because ultraviscous water crystallizes too rapidly to cubic ice containing stacking faults and intergranular water. The study demonstrates that water is a liquid over the 136-155 K range, thus removing the basis for a recent contention on its state.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".