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Author: Taylor Steven Geisler
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Prolonged exposure to inhaled micron-sized airborne particles is a known public health concern. These particles impact the health of staggering numbers of residents of polluted urban areas, as well as significant portions of the third world where it is still common to burn wood or charcoal indoors for cooking or heating. An understanding of the fate of inhaled particles in the lungs is useful for assessing their associated health risks, as well as improving the effectiveness of respiratory drug delivery techniques. The transport of microparticles is inseparable from behavior of the suspending airflow and this is studied using computational fluid dynamics techniques. The anatomy of the airways seems to have evolved to encourage turbulent airflow for functions such as mixing of flow to promote the warming and humidification of inhaled air, as well as for filtration. Large eddy simulation models are employed to capture turbulent flow in extremely complex patient-specific airway geometries. These collectively comprise the oral and nasal cavities, larynx, trachea, and the bronchial tree. The flow in anatomically-accurate rhesus macaque airways is also studied. Simulations are carried out for inspiratory flow rates corresponding to nominal Reynolds numbers in the hundreds to low-thousands yet somewhat surprisingly yield unsteady flows due to local geometric factors. A computed mean flow field is compared extensively with magnetic resonance velocimetry measurements carried out in the same computed-tomography--based lung geometry, showing good agreement. Microparticle deposition predictions are also verified. Focus is placed on the dynamics of the flow in the nasal airway, trachea, and bronchial tree. After becoming unsteady at constrictions in the upper airways, the flow is found to be chaotic, exhibiting fluctuations with broad-band spectra even at the most distal simulated airways in which the Reynolds numbers are as low as 300. The unsteadiness is attributed to the convection of turbulent structures produced in the upper airways as well as to local kinetic energy production throughout the bronchial tree.
Author: Taylor Steven Geisler
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Prolonged exposure to inhaled micron-sized airborne particles is a known public health concern. These particles impact the health of staggering numbers of residents of polluted urban areas, as well as significant portions of the third world where it is still common to burn wood or charcoal indoors for cooking or heating. An understanding of the fate of inhaled particles in the lungs is useful for assessing their associated health risks, as well as improving the effectiveness of respiratory drug delivery techniques. The transport of microparticles is inseparable from behavior of the suspending airflow and this is studied using computational fluid dynamics techniques. The anatomy of the airways seems to have evolved to encourage turbulent airflow for functions such as mixing of flow to promote the warming and humidification of inhaled air, as well as for filtration. Large eddy simulation models are employed to capture turbulent flow in extremely complex patient-specific airway geometries. These collectively comprise the oral and nasal cavities, larynx, trachea, and the bronchial tree. The flow in anatomically-accurate rhesus macaque airways is also studied. Simulations are carried out for inspiratory flow rates corresponding to nominal Reynolds numbers in the hundreds to low-thousands yet somewhat surprisingly yield unsteady flows due to local geometric factors. A computed mean flow field is compared extensively with magnetic resonance velocimetry measurements carried out in the same computed-tomography--based lung geometry, showing good agreement. Microparticle deposition predictions are also verified. Focus is placed on the dynamics of the flow in the nasal airway, trachea, and bronchial tree. After becoming unsteady at constrictions in the upper airways, the flow is found to be chaotic, exhibiting fluctuations with broad-band spectra even at the most distal simulated airways in which the Reynolds numbers are as low as 300. The unsteadiness is attributed to the convection of turbulent structures produced in the upper airways as well as to local kinetic energy production throughout the bronchial tree.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The human nasal cavities, each with an effective length of only 10cm, feature a wide array of basic flow phenomena due to their complex geometries. Dependent on such airflow fields are the transport and deposition of micro- and nano- particles in the human nasal cavities, of interest to engineers, scientists, air-pollution regulators, and healthcare officials. By utilizing advanced CAD and reverse engineering skills, a realistic model of the human nasal cavity was constructed from MRI image data for 3-D computer simulations. Assuming laminar quasi-steady airflow, dilute micro- and nano-particle suspension flows and local deposition efficiencies were analyzed for 7.5
Author: Chiu-sen Wang
Publisher: Elsevier
ISBN: 0080455018
Category : Technology & Engineering
Languages : en
Pages : 214
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Book Description
Inhaled Particles integrates all that is known about inhaled particles in a unified treatment. It aims to provide a scientific framework essential to a reasonable understanding of inhaled particles. The emphasis is placed on demonstrating the key roles of lung morphology on airflow and particle transport as well as identifying physical and biological factors that influence deposition. Special attention is paid to maintaining consistency of treatment and a balance between theoretical modeling and experimental measurements. The book covers all important aspects of inhaled particles including inhalability, aerosol dispersion, particle deposition, and clearance. It reviews concisely the basic background of lung morphology, respiratory physiology, aerodynamics, and aerosol science pertinent to the subject. Essential aspects of health effects and applications are also included. An easy-to-read, self contained introduction to the field An excellent source of updated research information Useful for students and professionals in aerosol science, environmental health science, occupational hygiene, health physics and biomedical engineering
Author: Jiyuan Tu
Publisher: Springer Science & Business Media
ISBN: 9400744870
Category : Technology & Engineering
Languages : en
Pages : 383
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Book Description
Traditional research methodologies in the human respiratory system have always been challenging due to their invasive nature. Recent advances in medical imaging and computational fluid dynamics (CFD) have accelerated this research. This book compiles and details recent advances in the modelling of the respiratory system for researchers, engineers, scientists, and health practitioners. It breaks down the complexities of this field and provides both students and scientists with an introduction and starting point to the physiology of the respiratory system, fluid dynamics and advanced CFD modeling tools. In addition to a brief introduction to the physics of the respiratory system and an overview of computational methods, the book contains best-practice guidelines for establishing high-quality computational models and simulations. Inspiration for new simulations can be gained through innovative case studies as well as hands-on practice using pre-made computational code. Last but not least, students and researchers are presented the latest biomedical research activities, and the computational visualizations will enhance their understanding of physiological functions of the respiratory system.
Author: Huawei Shi
Publisher:
ISBN:
Category :
Languages : en
Pages : 187
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Book Description
Keywords: CFD, drug delivery, airflow, particle deposition, nasal airway.
Author: Thomas Heistracher
Publisher:
ISBN:
Category : Air flow
Languages : en
Pages : 236
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Book Description
Author: René Pomeau
Publisher:
ISBN: 9780729404938
Category :
Languages : en
Pages : 876
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Book Description
Author: Mark L. Witten
Publisher: CRC Press
ISBN: 1439857725
Category : Medical
Languages : en
Pages : 361
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Book Description
Currently serving as a resource for the National Center for Toxological Research in their work with the Gulf Coast oil spill, this book presents current research conducted primarily by the airforce on the toxic effects of JP-8 jet fuel on the pulmonary, immune, dermal, and nervous systems. In all, the book considers 13 toxicology studies
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 11
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Book Description
The aim of this work is to measure deposition patterns and efficiencies of aerosol particles within realistic, single-pathway physical models of the tracheobronchial airways of humans and experimental animals over a range of particle sizes for a variety of respiratory modes and rates. This will provide data needed to assess the dose to the bronchial epithelium from inhaled radon progeny. In prior grant years an empirical expression for diffusional deposition efficiency of particles in the upper airways was obtained based on experimental data collected in central airway casts. The work also provided new quantitative data of airflow distribution in a realistic central airway cast for two species for both steady and pulsatile inspiratory flow and for expiratory flow. Theoretical studies were then extended based on a developing flow model. We concluded that although the developing flow model is a better predictor of the data than assumption of parabolic flow, the predicted deposition is significantly lower than that predicted by our best fit equation. In the current year the experimental results were evaluated in terms of the parametric solution of the convective diffusion equation.
Author: Xiaobo Zhu
Publisher:
ISBN:
Category : Aerosol therapy
Languages : en
Pages : 104
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Book Description
