Specific Heat and Transformations of Water in 1.4 and 1.8 nm Pore-MCMs
Bibliographic record
Abstract
Thermodynamic changes on transformations of water in MCMs of 1.4 and 1.8 nm diameter cylindrical pores were investigated by measuring the specific heat, C p,app, during cooling and during heating at 12 K/h rate in the 160–280 K range. The nature of the slow transformation was further investigated by measuring the dynamic specific heat by using temperature-modulated calorimetry. It led us to establish whether or not contributions to C p,app are thermally reversible. We found that a thermally reversible, monotonic change in C p,app of water occurs in 1.4 nm pore-MCM and a sigmoid-shape change occurs in 1.8 nm pore-MCM. C p,app measured during cooling and during heating is found to be the same at T < 227 K for 1.4 nm pore-MCM, and at T < 232 K for 1.8 nm pore-MCM, as is the real component of the complex specific heat, C p ′. This shows that the sigmoid-shape change in C p,app is not due to glass–liquid transition of water in the pores. This is further confirmed by showing that the C p,app features observed for water differ characteristically from the C p,app features of glycerol measured at the same 12 K/h rate. The continuous change in C p,app of water in the MCMs with change in T is reversible, and this indicates that water gradually converts to distorted ice-like structures on cooling, a process that is reversed on heating, until their fractional amounts reach a reversible equilibrium. The large sigmoid shape increase in C p,app on heating is attributed to the latent heat, similar to that seen on premelting of fine grain crystals. The findings put into question a conclusion from neutron scattering and NMR studies that water in 1.8 nm pores undergoes a structural and kinetic transition at ∼225 K, while remaining a liquid. Thermodynamic indication for a reversible low-density to high-density transition in water is not found.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot 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.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".