The characteristics of particle charging and deposition during powder coating processes with ultrafine powder
Bibliographic record
Abstract
In a preceding work, the mechanisms of particle charging and deposition during powder coating processes were explored with coarse polyurethane powder. In this paper, the developed mechanisms were further examined with ultrafine polyurethane powder in order to meet the growing needs for ultrafine powder in finishing industries. This study first verified the previous findings in particle deposition, which account for a cone-shaped pattern formed by deposited particles on the substrate and a rise in particle accumulation in the fringe region. It was further demonstrated with ultrafine powder that, as disclosed by using coarse powder, the primary charging of in-flight particles competes with back corona in particle deposition processes, and the highest deposition efficiency is a compromise by balancing their effects. In comparison with coarse powder, ultrafine powder presents a faster reduction in the deposition rate with extended spraying duration, but shows some superiority in the uniformity of the deposited layer. In the case of charging characteristics of the deposited particles, it was further substantiated with ultrafine powder that the secondary charging mechanism takes predominance in determining the distribution of local charge-to-mass ratios. It was also disclosed that ultrafine powder shows a decreasing charge-to-mass ratio with increased charging voltage in the deposited layer, opposite to the increasing tendency of coarse powder. However, it was commonly demonstrated by both coarse and ultrafine powders that the charge-to-mass ratio of the deposited particles decreases with the extended spraying durations. In comparison, ultrafine powder is more likely to produce uniform charge-to-mass ratio distributions in the deposited layer, which contrast sharply with the ones associated with the coarse powder. In conclusion, it is believed that this study supplements the preceding study and is of great help in providing a comprehensive understanding of the mechanisms of corona charging processes of different powders.
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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) | 0.000 | 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".