Photonic Doppler Velocimetry for Study of Rapid Penetration into Sand
Bibliographic record
Abstract
Abstract Quantitative description of the interaction of high-speed projectiles with soils is important for many engineering applications, and provides insights into high strain rate constitutive behavior. In this paper, a novel method known as photonic Doppler velocimetry (PDV), capable of producing time resolved velocity measurements, is adapted for the study of objects penetrating rapidly into sand. Fundamentals of PDV are described, and the applicability of the method is demonstrated by producing time-resolved velocity measurements of spherical projectiles penetrating Ottawa sand models at high velocities in the range of 300 m/s. Penetration tests demonstrate that PDV is capable of producing velocity measurements even after the penetrator has reached a depth well below the soil surface. Results of the tests confirmed that resistance to penetration increases as relative density of the sand deposit increases. Moreover, there appears to be a threshold penetration velocity in dense dry sand, below which resistance to penetration reduces considerably. A quantitative description of deceleration of penetrators in soils can be adequately provided for most of the penetration using a simple drag force model.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 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) | 0.001 | 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".