Investigation of shear-induced physical and chemical transformations of Fe microparticles in hydrocarbon- and fluorocarbon-based magnetorheological fluids
Bibliographic record
Abstract
Abstract Aging of magnetorheological fluids (MRFs) during the operation of mechanical devices is accompanied by degradation of both the particles and the fluid components. This study has shown that collisions among micron-size magnetic iron particles under shear can result in nanoscale changes to surface topography. Moreover, it has shown that shear-induced collisions can lead to redistributions among different oxidation state species in surface and near sub-surface regions of the particles. The redistributions among oxidation states and chemical species is the result of interfacial reactions that can involve adventitious oxygen, catalysis and other energetic processes that can act on either or both, the host fluid medium and additives introduced to stabilize the MRF. The interfacial chemistry is complex, inviting studies that couple macroscale processes (shear events in a clutch mechanism) with nanoscale inquiry into the effects of such processes. This study examined the chemical and morphological states of MRF particles subjected to continual shear loading in a rotary clutch device over well-defined periods of time for both hydrocarbon and fluorocarbon-based host fluids. New insights into chemical transformations, on and beneath, particle surfaces provide reference for better durability assessment, MRF formulation, and device design in the future. X-ray photoelectron spectroscopy iron, fluorine, oxygen and carbon depth profiles provided insight into the evolving oxidation states of the MRF particles. Over time, fluorine and oxygen insinuate themselves into the particle where they give rise to a host of different oxidized iron species. Simultaneously, the iron content of the surface diminishes. Scanning electron microscopy revealed how the particles transform from nascent nearly spherical shape prior to shear to irregular morphology in the clutch mechanisms. Transmission electron microscopy revealed carbon-rich residues with embedded nanoparticle fragments in aged MRF particle samples, suggesting that MRF particle surfaces may have served as reaction interfaces.
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 | 0.000 | 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".