Threshold Geometrical Dimensions of Stage II Cracks Versus Required Resolution of Crack-Detection Techniques
Bibliographic record
Abstract
Environmental-assisted cracks in pipeline steels usually undergo the following three sequential stages prior to the failure: • Stage 1 – crack initiation and early stage crack growth, in which cracks initiate at imperfections but grow slowly depth-wise with time. Crack length may be seen to increase either because of merging with new small cracks in the vicinity of an existing crack or faster crack growth at the crack tip. Some cracks pose little threat to pipeline steel integrity if they remain dormant. • Stage 2 – Increased crack growth rate where crack growth can be dictated by mechanical driving forces and crack growth rate increases with time. • Stage 3 – The final stage of crack growth where crack growth rate is very high. Typical crack management programs mitigate cracks prior to entering Stage III. It is of great importance that pipeline steels with Stage II cracks are detected, monitored, and managed to ensure operational pipeline integrity. Although a range of crack in-line inspection and detection techniques with varied detection limits are available, it is not clear how their detection limits match the threshold geometrical dimensions of Stage 2-cracks. This investigation is aimed to define critical geometrical dimensions of cracks that are considered to be Stage 2 cracks. The determination of critical geometrical dimensions of Stage 2 cracks was made with a consideration of a wide range of situations including pipeline operating conditions, susceptible environments for crack growth, metallurgical, fabrication and construction conditions of pipeline steels. A comparison of the threshold geometrical dimensions of Stage 2 cracks with the crack detection limits of modern crack inspection and detection techniques are made at the end of the paper.
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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 | 0.002 | 0.009 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 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".