Internal vapour pressure of plywood during hot pressing process (STSM funded by COST Action FP1006)
Bibliographic record
Abstract
Common wood based panels are produced hot pressed from wood material and adhesive, both containing water. The moisture content of wood might vary but could be on average, for instance, 5% whereas the moisture content of adhesive could be 50% or even more. The adhesive wood-ratio varies according to panel product and could be, for instance, 5%. At the beginning of hot pressing process the water evaporates due to rising temperature. This vapour is termed internal vapour pressure within the board. The increase in internal gas pressure derives mostly from vapour formation but the gas pressure rises somewhat also due to the compressing gas mixture that is in the void spaces of the board as well as the volatile organic compounds (deriving especially from the thermal degradation of hemicelluloses). Regardless of the fraction size of the wood material (e.g. fibre, chip, strand or veneer) the increased gas pressure causes problems, e.g. delamination, unless the hot press regime is controlled in a sufficient manner. The main purpose of this STSM was to determine how the internal gas pressure develops during hot pressing in the core part of self-bonded plywood where no adhesives are used. As a first step suitable methods were needed to determine. Finally, two separate pieces of equipment were applied successfully: PressMAN (by Alberta Innovates - Technology Futures) and EASYLOG (by GreCon). The test results provided also the information how temperature develops during hot pressing. Both pressure and temperature results are somewhat comparable to ordinary plywood production as the proportional water amount is in the same range as in the self-bonded plywood from veneers conditioned at RH 65% and 20°C. However, the lay-ups have great differences in terms of free and bound water. Therefore, it is suggested that the gas pressure develops less rapidly in the case of adhesive free lay-up.
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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".