Annular Extrudate Swell of a Fluoropolymer Melt
Bibliographic record
Abstract
Abstract Annular extrudate swell is studied for a fluoropolymer (FEP) melt using a tubular die. The rheological data of the melt have been fitted using (i) a viscous model (Cross) and (ii) a viscoelastic one (the Kaye – Bernstein, Kearsley, Zapas/Papanastasiou, Scriven, Macosko or K-BKZ/PSM model). Numerical simulations have been undertaken to study the extrudate swell of the FEP melt in an annular die. Compressibility, thermal and pressure effects on viscosity, and slip at the wall were taken into account. In all cases, slip at the wall is the dominant contribution reducing the swelling when compared with corresponding no-slip simulations. The viscous (Cross) simulations show that the swell decreases with increasing apparent shear rate, which is opposite to what happens in the extrusion of viscoelastic melts. On the other hand, the viscoelastic (K-BKZ) simulations correctly obtain increasing swelling with increasing shear (flow) rates. It was found that due to the mild viscoelasticity of FEP and its severe slip at the wall the swelling of this melt is relatively small, reaching values of about 20% for a wide range of apparent shear rates, exceeding 5000 s−1. This is corroborated by experimental observations.
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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".