We investigate the influence of bifurcation geometry, asymmetry of daughter airways, surfactant distribution, and physicochemical properties on the uniformity of airway recruitment of asymmetric bifurcating airways. To do so, we developed microfluidic idealized in vitro models of bifurcating airways, through which we can independently evaluate the impact of carina location and daughter airway width and length. We explore the uniformity of recruitment and its relationship to the dynamic surface tension of the lining fluid and relate this behavior to the hydraulic (P Hyd ) and capillary (P Cap ) pressure drops. These studies demonstrate the extraordinary importance of P Cap in stabilizing reopening, even in highly asymmetric systems. The dynamic surface tension of pulmonary surfactant is integral to this stability because it modulates P Cap in a velocity-dependent manner. Furthermore, the surfactant distribution at the propagating interface can have a very large influence on recruitment stability by focusing surfactant preferentially to specific daughter airways. This implies that modification of the surfactant distribution through novel modes of ventilation could be useful in inducing uniformly recruited lungs, aiding in gas exchange, and reducing ventilator-induced lung injury. NEW & NOTEWORTHY The dynamic surface tension of pulmonary surfactant is integral to the uniformity of asymmetric bifurcation airway recruitments because it modulates capillary pressure drop in a velocity-dependent manner. Also, the surfactant distribution at the propagating interface can have a very large influence on recruitment stability by focusing surfactant preferentially to specific daughter airways. This implies that modification of the surfactant distribution through novel modes of ventilation could be useful in inducing uniformly recruited lungs, reducing ventilator-induced lung injury.
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Parameter Estimation and Line Width Control of Robot Guided Inkjet Deposition
In the field of inkjet deposition, there is a lack of specific knowledge to detect and change drop volume to regulate fluid placement. In this paper, we present a novel control scheme to regulate drop diameter on a surface with unknown properties. We derive a model for line width as a function of nozzle velocity, valve duty cycle, and physical properties of fluid and surface. As many of these variables are generally unknown, we present a nonlinear estimator to estimate their cumulative effects as a single variable. Next, benefiting from our estimation knowledge, a closed-loop control method is designed to track a time-varying line width. Stability of both the estimator and control are established using Lyapunov stability theory, and the control is shown to be robust to errors in the estimator. Simulations and experimental results confirm the stability and performance of the approach.
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- Award ID(s):
- 1563424
- NSF-PAR ID:
- 10161914
- Date Published:
- Journal Name:
- 2018 Annual American Control Conference (ACC)
- Page Range / eLocation ID:
- 918 to 924
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.23919/ACC.2018.8431733
