Pulsed Field Gradient NMR Study of the Diffusion of H<sub>2</sub>O and Polyethylene Glycol Polymers in the Supramolecular Structure of Wet Cotton
Bibliographic record
Abstract
PFG NMR results are reported on H 2 O, PEG200, PEG1500, PEG8000, and PEG20000 in wet cotton fibers and H 2 O in wet cotton linters. The data are analyzed in terms of a two-site exchange model (water/cotton) and show that the probe molecules in fibers are trapped in cages. The cage size decreases from 10 to 2 μm as the probes' size increases from 0.23 to 9.2 nm, although the overall accessible volume only decreases from 50 to 20−30%. This behavior may be explained by size-exclusion effects on the connectivity and accessibility. Analysis of the diffusion coefficients at short diffusion times indicates that fiber cages are water pools held between the growth rings of the fiber. In linters these cages do not occur, and a freely diffusing signal from H 2 O in the amorphous region is observed with D = (4.5−8.9) × 10 -11 m 2 s -1, which when compared to the predicted value from the microviscosity of the amorphous regions gives a tortuosity of 2−4. Exit of all probes from linters and fibers takes 0.2 s and requires hydrogen bonds to be broken with an activation energy of 50 kJ mol -1 .
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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 | 0.000 |
| 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) | 0.001 | 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".