L-box—A tool for measuring the “yield stress”: A theoretical study
Bibliographic record
Abstract
Yield-stress fluids can form non-flat arrested profiles when they disembogue under the effect of gravity. Relying on this behavior, L-box tests have been used to retrieve fluid properties, specifically yield stress of Self-Consolidating Concrete (SCC) and cement paste. In this study, we aim to find a correlation between the final shape of the sample and the value of yield stress, using theoretical approaches. First, the Cauchy equation for yield-stress fluids is solved asymptotically, and an analytical expression for yield stress is presented. Then, to validate our assumptions in the first approach, the method of characteristics of perfect plasticity is investigated. We show that if the flow is inertialess, the viscosity of the sample does not affect the final shape considerably. We also investigate, in detail, the cases where the sample is not exactly a “simple” yield-stress fluid, i.e., exhibits slightly thixotropic behavior such as SCC and cement paste.
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".