Bibliographic record
Abstract
Formation of thin, black, well adhering weathering layers on pure sandstones used as building stone is a well known phenomenon, described in several countries and on several types of sandstones.In the Netherlands, sandstones from the Lower Saxony basin in Germany, notably the Bentheim and Obernkirchen sandstones, have been used for many prominent monuments from the 11th century onwards, and especially in the 14th till 17th century.Both sandstones show the formation of thin black weathering layers.In the present case, after characterization of the black weathering layer on a late 18th century façade cladded with Obernkirchen sandstone, a pilot test was performed to investigate the possibility of cleaning, and, especially, of any harmful effects to the original stone resulting from cleaning.Commercial firms have been invited to clean test panels on the façade.Two firms using a Nd-YAG laser have been invited, a third one using EDTA pastes.The latter proved not successful.In both cases, laser visually succeeded to remove the black layer.Possible deleterious effects of stone cleaning are twofold, viz.direct damage, such as removal of grains or patina from the original stone and damage to working of the stone, or indirect damage, that may arise from a different hygric behaviour of the stone (and façade as a whole) after cleaning.The latter have not been evaluated.Direct damage was evaluated by combination of polarization-and-fluorescence (PFM) and scanning electron microscopy (SEM).Cleaning using a Nd-YAG laser under commercially realistic conditions did not result in any direct damage to the Obernkirchen sandstone.
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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 | 0.001 | 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) | 0.003 | 0.001 |
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".