An analysis of variation in moduli of elasticity and rupture in young Douglas fir
Bibliographic record
Abstract
The results of two hundred and fifty-eight static bending tests on young Douglas fir were obtained from the Vancouver Laboratory of the Forest Products Laboratories of Canada. Twenty-two trees had been sampled; seven of approximately sixty years of age from Port Moody, eight of about seventy years of age from Coombs (on Vancouver Island), and seven of approximately ninety years of age from Stave Lake. Stand site quality in each locality was similar and above average for second-growth fir from the coastal region of British Columbia. The laboratory's results were separated into two classes. Ninety-seven tests represented wood formed within the first five inches of radial growth in the tree. The remaining one hundred and sixty-one tests typified the older wood lying between the inner zone and the bark. Analyses of variance revealed highly significant differences in properties between zones. Wood from the inner zone had a faster growth rate, lower density (though wider bands of summerwood) and less strength and less stiffness in bending than wood from the outer zone. The influence of ring width, summerwood width and specific gravity on the moduli of elasticity and rupture was assessed for each zone by regression analyses. Ring width and summerwood width accounted for a significant amount of variation in modulus of elasticity and modulus of rupture in the two zones. Their influence on both moduli, however, was completely due to their association with specific gravity. Specific gravity, alone, accounted for almost twice as much of the variation in elasticity and bending strength as did ring width and summerwood width combined. The presence of compression wood in a few specimens from the outer growth zone weakened the relationship between modulus of elasticity and specific gravity in this zone but had no effect on the modulus of rupture — specific gravity relationship. In consequence, the influence of growth zone on modulus of elasticity could not be determined. The difference in average values of specific gravity between zones did not fully explain the similar difference between zones for average modulus of rupture values; an indication that radial growth zone in the tree had some influence on the bending strength independent to that exerted by density.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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 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".