Oscillatory velocity profiles and the pressure-flow relationship were measured in a 3:1 scale rigid model of the human central airways. A reciprocating pump provided flows with frequencies of 0.25, 1, 2 and 4 Hz and tidal volumes of 300, 500 and 1500 mL giving tracheal Womersley numbers up to 31 and peak tracheal Reynolds numbers up to 17000. A hot wire anemometer was used to measure velocities along two perpendicular diameters (one in the plane of the model and the other in the plane perpendicular to the model) at 10 stations distributed through the model. Velocities were also measured with and without a model larynx and with tracheal intubation in steady inspiratory flows. The flow distribution to the five lobar bronchi was identical in all experiments. / Oscillatory velocity profiles were compared with the steady velocity profiles at nearly identical Reynolds numbers. The flow in a branch was quasi-steady below a critical Strouhal number in agreement with an order of magnitude analysis. For quasi-steady oscillatory flows the velocity profile developed from an initially flat shape to the profiles characteristic of steady flow in branching tubes. Flows that were not quasi-steady exhibited relatively flat profiles over the entire respiratory cycle. The effects of tidal volume, frequency and the geometry of the airways on the velocity profiles were determined. / While the larynx produced a significant jet within the trachea it had no effect on the velocity profiles beyond the carina. The presence of a concentric endotracheal tube located halfway between the glottis and the carina had little effect on the velocity profiles in the main stem and the lobar bronchi. Inserting the tube further into the trachea altered the velocity profiles in the right upper lobar bronchus. / In oscillating flow the pressure was essentially uniform around the periphery of a branch in strong contrast to the results for steady flow. The pressure drop in oscillating flow was much larger than the pressure drop in steady flow at an equivalent flow rate. The functional form of the relationship between the pressure drop across the different branches of the model and the tracheal Reynolds number was similar to that suggested by earlier researchers, however the coefficients were very sensitive to the geometry of the model.

Thesis (PhDManufacturing,MechanicEng)--University of South Australia, 2002.

Thesis (PhD)--University of South Australia, 2000

Thesis (PhDManufacturing,MechanicEng)--University of South Australia, 2002.

Exposure to traffic pollution has become an increasing concern to public health. A number of studies have demonstrated that the air people breathe in while in transportation is particularly unsafe due to the high concentrations of carbon monoxide (CO), suspended particles (PM10, PM2.5 and PM1) and ultrafine particles (UFPs). Some studies have suggested that peak exposures of approximately one hour- a typical time spent in a transport micro-environment- may have more damaging health effects than the 24- hour sampling times current standards apply to Despite the widespread interest in health effects from exposure to traffic pollutants, there is a distinct lack of research of this kind in New Zealand. The research presented in this thesis was designed to assess the effect of traffic emissions on personal exposure. More specifically, this project intended to examine how exposures differed on different modes of transport and also to investigate the extent to which transport micro-environments such as car parks, bus stops and metro stations contributed to personal exposure levels. This study is the first of its type in New Zealand, which simultaneously monitored CO, PM and UFP concentrations in the transport micro-environment. Vehicular traffic emissions were shown to be a significant source of air pollution in populated urban areas, especially in the transport microenvironment. This results of this study showed that the mode of transport is a significant determinant of personal exposure to pollutants. The information gathered indicated slightly different results for Christchurch and Auckland, possibly due to variations in background levels, traffic counts and meteorological conditions at the time of monitoring. Results from the research also showed that built transport microenvironments could experience extremely high levels of pollutant exposures. Although commuters spend a relatively short time in such environments, such short-term peak exposures could contribute significantly to adverse health effects. The results presented here have relevance for both public health and for policies aimed at reducing human exposures to traffic-related air pollution. It is imperative to incorporate policies which ensure that such built environments are as safe as possible in terms of keeping exposure levels at a minimum.

Thesis (M. Eng. Sc.)--University of Adelaide, Dept. of Electrical and Electronic Engineering, 1986. / Includes bibliographical references (leaves 221-232).

Thesis (M.S.M.E.)--University of Delaware, 2007. / Principal faculty advisor: Xinyan Deng, Dept. of Mechanical Engineering. Includes bibliographical references.

Thesis (Ph.D.)--McMaster University, 2002. / Advisor: Susan Elliott. Includes bibliographical references. Also available on World Wide Web.

Thesis (Ph.D.)--McMaster University, 2002. / Advisor: Susan Elliott. Includes bibliographical references. Also available on World Wide Web.

Thesis (Ph. D.)--University of Tennessee, Knoxville, 2004. / Vita. Includes bibliographical references (p. 93-98). Also available online via the University of Tennessee Electronic Theses and Dissertations website (http://web.utk.edu/~thesis/etd.shtml).