Resonant Column Testing: The Inherent Counter EMF Effect
Bibliographic record
Abstract
Abstract The standard magnet-coil driving system in resonant column devices provides the required cyclic excitation; however, it inherently produces a counter electromotive force that opposes the motion. In this study, the resonant column is modeled as an electro-mechanical system to quantitatively examine the counter electromotive effect and to explore its effect on resonant frequency and damping ratio computed from voltage-based measurements. The model is verified with two independent sets of experiments. Experimental and analytical results show that the measurement bias is more pronounced on the damping ratio than on the resonant frequency, the damping bias is not a device constant but varies with frequency, and the error is particularly relevant in low-loss and low-stiffness specimens (such as dry sands at low confinement). The electro-mechanical model permits developing device-specific correction charts that can be used to reexamine previously published damping ratio data gathered with voltage-based resonant column procedures.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".