Bibliographic record
Abstract
This paper presents a case study of a Prestressed Concrete Cylinder Pipe (PCCP) system that is experiencing deterioration and a failure resulting from internal corrosion. The corrosion mechanism is Sulfuric Acid attack due to Hydrogen Sulfide gas (H2S) generated from the wastewater. The PCCP pipeline is located in Regina, Saskatchewan, Canada and was constructed in 1979. The nominal inside diameter is 1350 mm (54") and the pipeline was designed as a sewage force main. In 1999, approximately 75 m (246 feet) of the pipe failed and was replaced with HDPE pipe. In 2008, an internal inspection was conducted downstream of the failed section. The inspection was conducted using man entry and by close circuit television (CCTV). The inspection found five (5) pipe sections under severe corrosion attack where the interior concrete surfaces near the crown of the pipe had deteriorated exposing the reinforcing. Another nine (9) sections also showed early signs of H2S attack. A post inspection hydraulic analysis indicated the deteriorating pipe section does not flow full, and the hydraulic regime along this section is supercritical transitioning to subcritical resulting in a hydraulic jump forming within the pipe. The wastewater contains high concentration of sulfides. The turbulent flow conditions at the hydraulic jump exacerbate the release of H2S gas from the aqueous phase to the air phase. The H2S gas collects near the crown of the pipe and initiates corrosion attack on the concrete surface. A rehabilitation strategy was developed to extend the service life of the PCCP force main.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".