Characterization of the Spray Velocities from a Pressurized Metered-Dose Inhaler
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
BACKGROUND: Pressurized metered dose inhalers (pMDIs) are widely used to deliver aerosolized medications to the lungs, most often to relieve the symptoms of asthma. Over the past decade, pMDIs have been modified in several ways to eliminate the use of chlorofluorocarbons in their manufacture while increasing efficacy. Numerical simulations are being used more frequently to predict the flow and deposition of particles at various locations, both inside the respiratory tract as well as in pMDIs and add-on devices. These simulations require detailed information about the spray generated by a pMDI to ensure the validity of their results. METHODS: This paper presents detailed, spatially resolved velocity measurements of the spray emitted from salbutamol sulfate pMDIs obtained using optically triggered particle image velocimetry (PIV). Instantaneous planar velocity measurements were taken and ensemble-averaged at nine different times during the spray event ranging from 1.3 to 100 msec after a pneumatically controlled actuation. RESULTS AND CONCLUSIONS: The mean spray velocities were shown to be bimodal in time, with two velocity peaks and velocity magnitudes found to be much lower than published data from instantaneous single point measurements. Planar velocity data at each time step were analyzed to produce prescriptive velocity profiles suitable for use in numerical simulations. Spray geometry data are also reported. Statistical comparisons from several thousand individual spray events indicate that there is no significant difference in measured velocity among (1) two brands of pMDI canisters, (2) two pMDIs of the same brand but having different lot numbers, and (3) a full pMDI versus an almost empty pMDI. The addition of a secondary air flow of 30 SLPM (to represent simultaneous inhalation and spray actuation) deflected the spray downward but did not have a significant effect on flow velocity. Further experiments with an added cylindrical spacer revealed that within the spacer, the spray direction and cone angle were altered, although the peak velocities remained similar.
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.
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) | 0.001 | 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 it