Modeling the Ultraviolet Photodegradation of Rigid Polyurethane Foams
Bibliographic record
Abstract
Before the Montreal Protocol of 1987 and the subsequent phasing-out of chlorofluorocarbons (CFCs) in industrial applications, rigid polymer foams were made using these compounds as secondary blowing agents. The CFCs remain trapped in the gaseous part of the cellular foam structure, and once discarded these foams constitute a significant reservoir for the environmental release of ozone-depleting chemicals. Environmental degradation of the foam accelerates this process. Of particular interest in this work is the degradative effect of ultraviolet (UV) light on rigid polyurethane foams. Foams were subjected to accelerated weathering conditions and then viewed with a scanning electron microscope. The thin cell membranes near the foam surface degrade when exposed to UV light, leaving only a network of polymer struts that offers negligible resistance to the escape of CFCs or any other gases contained within. This effect has been reproduced qualitatively through simulated weathering of a computer-generated foam structure. If enough is known about the optical properties and photosensitivity of the polymer foam, this simulation technique can be used to estimate the rate of weathering penetration in any situation where photodegradation is the primary concern.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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".