No country for old borosilicate triple-point-of-water cells
Bibliographic record
Abstract
Abstract Temperature calibration labs all around the world typically maintain a set of several triple-point-of-water (TPW) cells for regular measurements using the International Temperature Scale of 1990 (ITS-90). This set often includes more-than-10-year-old TPW cells made from a borosilicate glass. In this paper we summarize the problems with old borosilicate TPW cells, using the available literature data, the results of CCT.K7-2021 key comparison and NRC TPW measurements, and highlight the solution to these issues—vitreous-silica TPW cells. The latter have an exceptional long-term stability, as we demonstrate by using: (a) comparative measurements of the same-age, same-manufacturer vitreous-silica and borosilicate TPW cells at NRC in a period from 2007 to 2021, and (b) inductively coupled plasma-mass spectrometry (ICP-MS) analysis of impurities present in the 18 year-old vitreous-silica outlier, cell Q325. Remarkably, not only all NRC vitreous-silica TPW cells remained stable over a 15 years time period, unlike their borosilicate counterparts, but the amount of impurities in the ‘coldest’ cell Q325 (−31 μK from the intercomparison reference value) is comparable to that in the newly purchased vitreous-silica cells. We argue that the most accurate TPW measurements, such as for defining the national TPW references and for the international key comparisons, should rely exclusively on vitreous-silica TPW cells.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| 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 | 0.000 |
| 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 teacher head, 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".