The shape of liquid Pb inclusions embedded in a solid Al matrix was investigated at temperatures between 300 and 500°C using in-situ electron microscopy. Inclusion shapes in the size range from a few nanometers to about 150 nanometers were found to depend on size, temperature and thermal history. During isothermal annealing after melting, small inclusions rounded off while larger inclusions remained faceted until the temperature was raised to about 500°C. During subsequent cooling, inclusions refaceted, although less strongly than during heating. The shape hysteresis between heating and cooling cycles was found to be due to the barrier of ledge nucleation necessary to advance the faceted interfaces. It is shown that this kinetic barrier can explain the observed dependence on size and temperature, and that the {111} interface undergoes a roughening transition at about 550°C. Even under conditions of kinetic limitation it was possible to measure local equilibrium by modeling kinetically limited inclusions as a droplet in a crevice. For this type of measurement, the hysteresis between heating and cooling cycles disappeared, and the true equilibrium shape could be derived. The anisotropy of interfacial energy was shown to be significantly smaller than previously reported, and at about 2 %, similar to the anisotropy of the surface energy for fcc metals.From the width of facets on the equilibrium shape, the step energy was determined to be at 350°C. ε = 1.9⋅10 -11 J / m 1 9/29/00
Background We aimed to determine the development in the use of video laryngoscopy over a 9‐year period, and its possible impact on airway planning and management. Methods We retrieved 822,259 records of tracheal intubations recorded from 2008 to 2016 in the Danish Anaesthesia Database. The circumstances regarding pre‐operative airway assessment, the scheduled airway management plan and the actual airway management concerning video laryngoscopy were reported for each year of observation. Further, the association between year of observation and various airway management related outcomes was evaluated by multivariate logistic regression. Results There was a significant increase in airway management with ‘advanced technique successfully used within two attempts’ from 2.7% in 2008 to 15.5% in 2016 (p < .0001). This predominantly reflects use of video laryngoscopy. The prevalence of tracheal intubations ‘scheduled for video laryngoscopy’ increased from 3.5% in 2008 to 10.6% in 2016 (p < .0001). We found a significant increase in the prevalence of anticipated difficulties with intubations by direct laryngoscopy from 1.8% in 2008 to 5.2% in 2016 (p < .0001). The prevalence of failed tracheal intubations decreased from 0.14% in 2008 to 0.05% in 2016 (p < .0001). Conclusion From 2008 to 2016, a period of massive implementation of video laryngoscopes, a significant change in airway management behaviour was recorded. Increasingly, video laryngoscopy is becoming a first‐choice device for both acute and routine airway management. Most importantly, the data showed a noticeable reduction in failed intubation over the time of observation.
The shape of liquid Pb inclusions in Al was investigated by in-situ electron microscopy over a temperature interval from 300 to 500°C. The inclusion shape was found to depend on size and temperature. During isothermal annealing after melting, small inclusions rounded off while larger inclusions remained faceted until the temperature was raised to about 500°C. During subsequent cooling, inclusions refaceted, although less strongly than during heating. The shape hysteresis between heating and cooling cycles was found to be due to the barrier of ledge nucleation necessary to advance the faceted interfaces. The observations show that the step energy depends on temperature and its disappearance at about 540-600°C indicates a roughening transition.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.