Temperature excursion: difference between revisions
Diff·revision 27 → 28·05:35, 29 Jul 2025
Difference between revision 27 and revision 28 of Temperature excursion. 5 lines changed; the page grew by 873 bytes.
| Revision 27 — 20:15, 22 Jul 2025 StopperingSteff (talk) add short description 12,436 bytes +227 | Revision 28 — 05:35, 29 Jul 2025 RepackRadek (talk) ce 13,309 bytes +873 | ||
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| 81 | {{math|e^{−10000/295.15} = e^{−33.8811}}} and {{math|e^{−10000/278.15} = e^{−35.9518}}} | 81 | {{math|e^{−10000/295.15} = e^{−33.8811}}} and {{math|e^{−10000/278.15} = e^{−35.9518}}} |
| 82 | 82 | ||
| + | 83 | === Why the two means diverge === | |
| + | 84 | The divergence is a direct consequence of convexity. Degradation rate is a convex function of temperature, so the average of the rates at two temperatures exceeds the rate at their average temperature. Mean kinetic temperature is defined as the temperature whose rate equals the average rate, and therefore always lies at or above the time-weighted arithmetic mean, with equality only for a constant profile. | |
| + | 85 | ||
| + | 86 | The gap widens with the spread of the profile. For the 30-day case above, a spread of 17 °C produced a gap of 2.9 °C. For the extreme cycle worked at [[Cold chain]], a spread of 28 °C produced a gap of 8.1 °C. A record with a narrow spread can be summarised by its arithmetic mean with little error; a record with a wide spread cannot, and it is precisely the wide-spread records that arise from excursions.{{r|haynes1971}} | |
| + | 87 | ||
| 83 | == References == | 88 | == References == |
| 84 | {{reflist}} | 89 | {{reflist}} |