High Temperature Airflow and Particle Deposition in Human Upper Lung-airway Models with a Focus on the Mucus-layer Dynamics PDF Download
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Author: Nilay Atul Kulkarni
Publisher:
ISBN:
Category :
Languages : en
Pages : 84
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Author: Nilay Atul Kulkarni
Publisher:
ISBN:
Category :
Languages : en
Pages : 84
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Book Description
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: 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:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
People may inhale 100 millions of particles each day, including toxic particulate matter as well as drug aerosols. Some of those deposited in the respiratory system can be either harmful or therapeutic to humans depending upon the particle material, deposition site, and local concentration. These transport and deposition phenomena as well as the resulting biomedical processes are greatly determined by the airflow field, particle properties, breathing pattern, and geometric airway characteristics. Realistic models of tracheobronchial and nasal⁄oral- tracheobronchial airways were built. Airflow and particle transport and deposition in these airway models were investigated in detail by mainly using the validated, in-house FORTRAN code CFPD (computational fluid-particle dynamics), which is a cell-centered, finite volume multi-block code. Both laminar and transitional-turbulent-laminar flows were considered for different transient and steady inhalation flow rates and inlet velocity profiles. The resulting effects of transients, upstream conditions and geometric characteristics, i.e., spatial angle and/or cartilaginous rings, are fully discussed. A new code based on the lattice-Boltzmann method (LBM) has been developed and validated to investigate airflow patterns and pressure changes in representative alveolar structures of the human respiratory zone. The new idea of targeted drug aerosol delivery technology was numerically tested for a more realistic human airway configuration and thereby addressing the problem of inter-subject variability. Specifically, controlled air-particle streams were studied using the oral and asymmetric tracheobronchial airway models. The results were compared with data obtained for a symmetric Weibel Type A tracheobronchial airway model.
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: James D. Crapo
Publisher:
ISBN:
Category : Medical
Languages : en
Pages : 400
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Book Description
Extrapolation Modeling, Advancements and Research Issues in Lung Dosimetry; Lung Structure, Function Relationships; Species Differences in Airway Cell Distribution and Morphology; Alternative Methods to Evaluate Species Differences in Upper Airway Structure, Function; Preparation of Rat Nasal Airway Casts and Their Application to Studies of Nasal Airflow; Age Related Morphometric Analysis of Human Lung Casts; Anatomical Modeling of Microdosimetry of Inhaled Particles and Gases in the Lung; Experimental Dosimetry; Particle Deposition at the Alveolar Duct Bifurcations; Effects of Airway Branch Angle, Branch Point Number, and Gravity on Particle Deposition and Retention; Regional Deposition of Inhaled Particulates in Conducting Airways and Lung Segments; The Physical Properties of Mainstream Cigarette Smoke and Their Relationship to Deposition in the Respiratory Tract; Localization of 14C Dotriacontane Labeled Cigarette Smoke Particulate in the Dog Lung; Human Lung Clearance Following Bolus Inhalation of Radioaerosols; Effects of Ventilatory Patterns and Pre-existing Disease on Deposition of Inhaled Particles in Animals; Nasopharyngeal Uptake of Ozone in Humans and Animals; New Methods; Regional Dosimetry of Inhaled Particles Using SPECT; Dual Laser Doppler System for Real Time, Simultaneous Characterization of Aerosols by Size and Concentration; Dosimetry of Inhaled Particles by Means of Light Scattering; Modeling Approaches; Issues That Must Be Addressed When Constructing Anatomical Models of the Developing Lung; Significances of the Variability of Tracheobronchial Airway Paths and Their Air Flow Rates to Dosimetry Model Predictions of the Absorption of Gases; Predicting Respiratory Tract Clearance in Man; The Role of Particle Hygroscopicity in Aerosol Therapy and Inhalation Toxicology; Age-Dependent Lung Dosimetry of Radon Progeny; Deposition and Retention Modeling of Inhaled Cadmium in Rat and Human Lung, An Example for Extrapolation of Effects and Risk Estimation.
Author: Jonathan Steffens
Publisher:
ISBN:
Category : Atmospheric deposition
Languages : en
Pages : 230
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Book Description
"Particle deposition in the respiratory tract is studied in order to better understand the negative health effects due to cigarette smoke inhalation. Until recently, idealized models of the respiratory airways based on the original Weibel model have been used to calculate deposition. These models consist of symmetric bifurcating airways and do not take into account variations of airway diameter, and asymmetry in the human respiratory tract. Until recently, little work has been done to accurately recreate the entire upper respiratory tract including the oral cavity, pharynx, and larynx. Technological improvement has changed the way in which researchers approach this problem. With the advent of high resolution scans of the respiratory tract, accurate replica models can be created to better predict cigarette smoke particle (CSP) deposition. These models recreate actual lung geometries found in patients. For this thesis, two realistic geometric models are created. One is based on an adult male and the other on an adolescent male. CSP deposition is determined for both models in order to compare the difference cased by age in smoking. In addition, an unsteady breathing curve, indicative of realistic smoking behavior is utilized to more accurately represent the breathing conditions. Both models consist of the oral cavity, throat, larynx, trachea, and first five to seven generations of the lungs. The adult model is based on a dental cast of the mouth, a CT scan of the throat and larynx, and images based on the National Institute of Health's Visible Human Project for the tracheobronchial tree. The adolescent model is based upon a scaled oral cavity and CT scans of the rest of the reparatory tract. The program 3D Doctor is used to reconstruct the two dimensional CT scan images into a three dimensional model. VPSculpt and SolidWorks are used to combine the different parts of the models and clean up the geometry. The geometry is meshed in Gambit and exported to the Computational Fluid Dynamics (CFD) software package Fluent to perform the fluid flow and particle deposition analysis. The Fluent Discrete Phase Model (DPM) is used to determine particle trajectories and deposition. It is found that deposition increases with the size of the inhaled particles. Particles tend to deposit towards the back of the throat, the area of the trachea just below the glottis, and at bifurcations in the airways. However, when compared to other studies in literature, deposition tended to be higher with smaller particle sizes, but more comparable with larger particle sizes. Adolescent deposition was found to be lower than adult deposition for all particle sizes."--Abstract.
Author: Goutham Mylavarapu
Publisher:
ISBN:
Category :
Languages : en
Pages : 225
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Book Description
Computational modeling of biological systems have gained a lot of interest in biomedical research, in the recent past. This thesis focuses on the application of computational simulations to study airflow dynamics in human upper respiratory tract. With advancements in medical imaging, patient specific geometries of anatomically accurate respiratory tracts can now be reconstructed from Magnetic Resonance Images (MRI) or Computed Tomography (CT) scans, with better and accurate details than traditional cadaver cast models. Computational studies using these individualized geometrical models have advantages of non-invasiveness, ease, minimum patient interaction, improved accuracy over experimental and clinical studies. Numerical simulations can provide detailed flow fields including velocities, flow rates, airway wall pressure, shear stresses, turbulence in an airway. Interpretation of these physical quantities will enable to develop efficient treatment procedures, medical devices, targeted drug delivery etc. The hypothesis for this research is that computational modeling can predict the outcomes of a surgical intervention or a treatment plan prior to its application and will guide the physician in providing better treatment to the patients. In the current work, three different computational approaches Computational Fluid Dynamics (CFD), Flow-Structure Interaction (FSI) and Particle Flow simulations were used to investigate flow in airway geometries. CFD approach assumes airway wall as rigid, and relatively easy to simulate, compared to the more challenging FSI approach, where interactions of airway wall deformations with flow are also accounted. The CFD methodology using different turbulence models is validated against experimental measurements in an airway phantom. Two case-studies using CFD, to quantify a pre and post-operative airway and another, to perform virtual surgery to determine the best possible surgery in a constricted airway is demonstrated. The unsteady Large Eddy simulations (LES) and a steady Reynolds Averaged Navier Stokes (RANS) approaches in CFD modeling are discussed. The more challenging FSI approach is modeled first in simple two-dimensional anatomical geometry and then extended to simplified three dimensional geometry and finally in three dimensionally accurate geometries. The concepts of virtual surgery and the differences to CFD are discussed. Finally, the influence of various drug delivery parameters on particle deposition efficiency in airway anatomy are investigated through particle-flow simulations in a nasal airway model.
Author: Sponsored by The Health Effects Institute
Publisher: National Academies Press
ISBN: 0309037263
Category : Science
Languages : en
Pages : 703
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Book Description
"The combination of scientific and institutional integrity represented by this book is unusual. It should be a model for future endeavors to help quantify environmental risk as a basis for good decisionmaking." â€"William D. Ruckelshaus, from the foreword. This volume, prepared under the auspices of the Health Effects Institute, an independent research organization created and funded jointly by the Environmental Protection Agency and the automobile industry, brings together experts on atmospheric exposure and on the biological effects of toxic substances to examine what is knownâ€"and not knownâ€"about the human health risks of automotive emissions.
Author: National Research Council (U.S.). Subcommittee on Airborne Particles
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 376
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Book Description
