Probability of Failure Analysis due to Internal Corrosion in Cast-Iron Pipes
Bibliographic record
Abstract
In cast-iron pipes, chlorine consumption due to internal corrosion is high compared with consumption caused by other water-quality factors in such systems and may be considered as an approximate indicator of the rate of internal corrosion. Herein, a relationship is developed that determines the rate of internal corrosion as a function of the chlorine concentration, the chlorine decay constant, and the velocity of the water in a pipe segment with a given length and diameter. These factors may be considered uncertain at any given time and the probability of mechanical failure due to the thinness of the pipe wall caused by internal corrosion throughout the pipe life is estimated using Monte Carlo simulation, the first-order reliability method, and the second-order reliability method to account for these uncertainties. The results indicate that the likelihood of failure is nearly 50% by the 80th year for a cast-iron pipe length of 6 m and a diameter of 203 mm, and that the affect of internal corrosion on the pipe wall thickness and thus mechanical failure is lower than, but on the same order of magnitude as, the effect of external corrosion.
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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 | 0.007 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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".