The Critical Frequency in Biphasic Media: Beyond Biots Approach
Bibliographic record
Abstract
Biot's theory for wave propagation in biphasic media is still of great influence on current research and its applications in engineering and geosciences. In particular, the characteristic frequency introduced by Biot is used to distinguish a viscosity-dominated low frequency range from an inertia-dominated high frequency range. An understanding of the transition between these ranges of contrasting dominance of mechanisms is of vital importance for the interpretation of experiments and the basis of new theories. Biot derived the characteristic frequency on the microscale and questions remain regarding its correct transformation to the macroscale. Specifically, three aspects are neglected due to simplifying assumptions on the microscale: inertia of the solid, elasticity of the solid, and a frequency-dependent momentum interaction. Corrections accounting for these aspects are particularly significant for systems with a weak solid skeleton and a rather incompressible fluid. Neglection of these corrections appears however often justified for typical systems of rocks or soils. Experiments were conducted in which waves propagate through elastic tubes of different materials (steel, silicone) filled with various fluids (air, water, Na-Polywolframat). These experiments are supposed to represent the micro-scale mechanisms in single pores. The mismatch between experimental records and theoretical predictions suggests that some of the assumptions made in current theoretical treatments of the problem require further consideration before a reliable upscaling can be undertaken.
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 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| 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".