Interfacial tension between water and pentane saturated with methane
Bibliographic record
Abstract
The plugging of natural gas pipelines caused by hydrate formation has been recognized as a problem in the oil and gas industry for approximately 90 years. Interfacial tension is an important physical property to understand the dynamics of multiphase flow, namely, natural gas, condensate, and water, inside the pipelines. This paper describes our measurements of the interfacial tension between water and pentane saturated with methane as a model for the fluids in the pipelines transporting gas and condensate. The measurements were conducted by the pendant drop method in the temperature range between 278.2 K and 293.2 K, and the methane pressure range between 1.1 MPa and 13.7 MPa. The uncertainty of the measurements is typically below 1.5 mN ∙ m −1 . The interfacial tension decreased with increasing temperature at 2 MPa. As for the pressure dependence at 288.2 K, with increasing pressure, the interfacial tension decreased from 49.12 mN ∙ m −1 at 1.1 MPa to 47.64 mN ∙ m −1 at 4.0 MPa. The interfacial tension remained roughly constant until 8.7 MPa with the value being 48.02 mN ∙ m −1 and then increased to 59.81 mN ∙ m −1 at 12.9 MPa. The decrease of the interfacial tension between 1.1 MPa and 4.0 MPa could be attributed to the increase of the methane molecule adsorption at the interface. In the pressure range between 4.0 MPa and 8.7 MPa, it is likely that the methane adsorption at the water – pentane interface became saturated. The increase of the interfacial tension above 8.7 MPa is a novel phenomenon which requires further investigation. Interfacial tensions of water and pentane saturated with methane at 293.2 K and 288.2 K (this work), water and decanesaturated with methane at the same temperatures (Kodera et al., 2020), and water and pentane without methane.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 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".