Comparision of Density Measurement Methods for Unidirectional Flax-Epoxy Polymer Composites
Bibliographic record
Abstract
Density is a decisive factor in determining one of the most important advantages of flax fiber-reinforced polymer (FFRP) composites, i.e. their relatively low weight leading to high specific properties. As a fundamental physical property of composites, density enters in many engineering design and quality control calculations and its value is a determining factor for several applications. Especially, we need precise material properties including density so as to develop efficient numerical models to these materials. In this work, three density measurement methods were evaluated and compared: Helium-gas pycnometry and Archimedes with two different immersing liquids, water and ethanol. The results show that Helium-gas pycnometry and Archimedes with ethanol gave similar and repeatable results, whereas using water resulted in much lower values. The density values were all in the range of reported values. However, Helium-gas pycnometry or Archimedes using ethanol are recommended for more precision in measuring the density of FFRP composites.
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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 | 0.005 | 0.010 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 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".