AC Corrosion at Other Frequencies Part a: Field Investigation and Mitigation
Bibliographic record
Abstract
Abstract A 2018 field investigation on an NPS 6, approximately 4 km long, liquid pipeline, identified a rectifier as the likely source of the elevated DC and AC current densities, which resulted in AC corrosion anomalies detected during in-line inspections (ILI). The findings of this case study, presented in the NACE Corrosion 2019 Paper No. 13188, indicated that the 120 Hz rectifier ripple may have contributed to the accelerated AC corrosion at this location. This follow-up paper is Part A of a two-part further investigation into corrosion rates on cathodically protected structures due to AC frequencies other than the fundamental power frequencies of 50 Hz and 60 Hz. Part A involves additional field testing on the subject pipeline, and commissioning of the recommended AC mitigation and monitoring systems. Part B of this investigation will be presented in a separate paper (NACE Corrosion 2020 Paper No. 14916) and will discuss the results of laboratory testing to determine corrosion rates of cathodically protected steel in simulated soil conditions at various AC frequencies.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 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) | 0.002 | 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".