Weibel symmetric model

The estimated number of tubes in each airway generation depends on the bifurcation model used in describing the tracheobronchial tree. Though bronchial bifurcations are asymmetric, symmetric models, exemplified by Weibel, or asymmetric models, such as one suggested by Horsfield, can... 

Fig. 2 The Weibel symmetrical branching model of the lung. (From Ref. 12.)... 

Bakd et al. theoretically analyzed simultaneous gas flow and diffusion in Weibel s symmetric model. Th applied a time-varying flow with simultaneous longitudinal diffusion and concluded that convective mixing is much less important than mixing induced by molecular diffusion. 

The Henry s law constant in water was used in the McJilton et al. uptake model to determine the equilibrium concentration of ozone and sulfur dioxide at the surface of a simulated mucus film along the airways in Weibel s symmetric model.It is also used to determine the concentration of absorbed gas at the surface of the mucus when the pollutant gas undergoes a homogeneous or heterogeneous chemical reaction within the mucus layer. 

This trumpet model was originally introduced by Scherer et al. (141) for simulations of intrapulmonary gas transport and is based on a morphometric data set proposed by Weibel (5). In Weibel s model, the structural parameters of each airway generation are described by average values, so that all airways of a given generation are identical, as are all pathways leading to a specific airway generation. The model is, therefore, termed symmetrical or deterministic. ... 

Dosimetry. Dosimetry for inhaled Rn-d particles has made significant advances over the past twenty years. Lung modelling, based initially to a large extent on the WEIBEL A -symmetrical lung model, has been... 

Weibel and Raabe et al. have shown that the structure of human bronchial airways can be approximated as a network of repeatedly bifurcating tubes. The bifurcations are generally asymmetric. In most computer models, however, symmetric conditions are assumed. 

Figure 14 Modeled local deposition in the tracheobronchial and alveolar region Deposition estimates were earried out for the symmetrical morphometric model of Weibel (5) at a tidal volume of700 cm an inspiratory flow rate of500 em s , and an end-inspiratory pause of 0.5 s. The percentage deposition per airway generation is given for partieles with aerodynamie diameters ranging between 1.6 and 15.8 pm. The percentage quoted is the fraction of all aerosol particles that pass through the glottis. (From Ref. 129.)...

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