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Record W1511834497 · doi:10.1063/1.1466469

Does water need a new Tg?

2002· article· en· W1511834497 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueThe Journal of Chemical Physics · 2002
Typearticle
Languageen
FieldMaterials Science
TopicMaterial Dynamics and Properties
Canadian institutionsMcMaster University
Fundersnot available
KeywordsEnthalpyThermodynamicsDifferential scanning calorimetryGlass transitionEndothermHeat capacitySofteningMaterials scienceAtmospheric temperature rangeChemistryPolymerOrganic chemistryPhysics

Abstract

fetched live from OpenAlex

The basis for the conjecture that water’s Tg may be 165±5 K [Velikov, Borick, and Angell, Science 294, 2335 (2001)] has been examined. It is shown that (i) differential scanning calorimetry (DSC) scans provided by Hallbrucker and Mayer [J. Phys. Chem. 91, 503 (1987)], and used as a basis for the conjecture, do not represent the heat capacity of the assumed, slow-cooled glassy water or of hyperquenched glassy water, and (ii) there is no fundamental requirement that the excess heat capacity show a peak at T<Tg—instead the peak may appear at T<Tg, at Tg, or at T>Tg. On heating, the enthalpy of glasses produced by hyperquenching or rapid cooling begins to decrease at a much lower T than that of the glasses obtained by slow cooling. Annealing increases this temperature toward Tg, and the enthalpy decrease continues at T above Tg. In the enthalpy relaxation region, the diffusion coefficient of the hyperquenched glassy state is higher than that of a slow-cooled glassy state at a given T, and a local minimum in the DSC scan does not appear at T<Tg in several glasses. These findings remove the basis for the conjecture that water’s Tg may be ∼165 K. Several analyses confirm that the known sigmoid-shape endotherm of glassy water represents the glass-softening range with onset temperature of 136 K. The DSC scans of a glassy state similar to that of water have been simulated by using a nonlinear, nonexponential enthalpy relaxation formalism. These show that a peak in the difference scan of the simulated glass appears above its Tg of 136 K.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesInsufficient payload (model declined to judge)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.021
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0010.000

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.

Opus teacher head0.016
GPT teacher head0.204
Teacher spread0.187 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it