Influence of laser beam size on measurement sensitivity of thermophysical property gradients in layered structures using thermal-wave techniques
Bibliographic record
Abstract
The influence of the photothermal laser source beam size on the measurement sensitivity of layered systems using photothermal radiometry (PTR) is presented. Based on an appropriate theoretical model, widely different behaviors of the photothermal amplitude and phase in terms of combinations of thermophysical properties (i.e., thermal conductivity and thermal diffusivity) between a thin coating and the substrate are observed. The beam size effect on PTR measurement sensitivity is theoretically examined and experimentally demonstrated using a carbonitrided C1018 steel sample. The experimental results of using a variable size laser beam for the carbonitrided C1018 sample validate the theoretical prediction, in which an expanded beam exhibits a much larger magnitude change in both amplitude and phase as a function of frequency than measurements with a focused beam. The fitted thermal conductivity and thermal diffusivity based on the assumed industrially relevant range of effective hardness case depth gives the approximate range of the change in thermal conductivity and thermal diffusivity of C1018 steels after the carbonitriding process.
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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 | 0.002 | 0.008 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 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".