Simulation of Respiratory System for Identifying Airway Occlusion

2000 ◽  
Author(s):  
A. M. Al-Jumaily ◽  
P. Mithraratne
Keyword(s):  
Theoretical Model ◽  
Acoustic Wave ◽  
Dynamic Response ◽  
Respiratory System ◽  
Input Impedance ◽  
Symmetric Model ◽  
Airway Occlusion ◽  
Wave Approach ◽  
Model Based ◽  
Compliant Walls

Abstract A theoretical model is developed to study the dynamic response of the respiratory system using Weibel symmetric model based on the acoustic wave approach. Both rigid and compliant walls with rigid and compliant termination are investigated separately. For each case the response (normalised input impedance against prorogation frequency) is examined for occlusion at each generation from alveolar sacs up to the distal end of the trachea systematically.

Asymmetrically Respiratory System Simulation for Identifying Airway Occlusion

2001 ◽  
Author(s):  
A. M. Al-Jumaily ◽  
Y. Al-Fakhri
Keyword(s):  
Theoretical Model ◽  
Dynamic Characteristic ◽  
Respiratory System ◽  
Input Impedance ◽  
System Simulation ◽  
Acoustic Response ◽  
Frequency Spectra ◽  
Airway Occlusion ◽  
Airway Walls ◽  
The Impact

Abstract A theoretical model is developed to investigate the dynamic characteristic of a healthy and an occluded asymmetric respiratory system. The model takes the elastance and inertance of the airway walls into consideration. Frequency spectra of the input impedance determined at the throat are generated and examined for two regimes of airway terminations and for occlusion at each generation from the end terminal (alveolar sacs) up to the proximal end of the trachea. In the asymmetric arrangement the impact of merging dissimilar flows due to different airways geometry from the adjacent regions is considered. Further, the effect of the nature of the terminal impedance (ie. rigid termination or compliant termination) on the acoustic response is also investigated.

Significance of Elastance Variation on Respiratory System Dynamics

2002 ◽  
Author(s):  
A. M. Al-Jumaily ◽  
Y. Al-Fakhri
Keyword(s):  
Dynamic Response ◽  
System Dynamics ◽  
Frequency Spectrum ◽  
Respiratory System ◽  
Input Impedance ◽  
Airway Wall ◽  
Asymmetric Structures ◽  
Asthma Attack ◽  
Lung Structure ◽  
Recursion Formulas

The sensitivity of the respiratory system dynamic response to variations in the wall elastance is investigated. The acoustical approach is used to determine the impedance at the throat using impedance recursion formulas. Both symmetric and asymmetric structures are considered. The response of the lung structure indicates that when the airway wall elastance varies, as the case during an asthma attack, the overall normalized input impedance frequency spectrum could be used to give a reasonable signature for identifying such abnormality.

Nodule count in ductile iron: theoretical model based on Weibull statistics

2005 ◽  
Vol 18 (3) ◽  
pp. 156-162 ◽  
Author(s):  
E. Fraś ◽  
K. Wiencek ◽  
M. Górny ◽  
H. F. López
Keyword(s):  
Theoretical Model ◽  
Ductile Iron ◽  
Weibull Statistics ◽  
Nodule Count ◽  
Model Based

Vibration isolation performance of nonobstructive particle damping in a machine rack

2018 ◽  
Vol 25 (5) ◽  
pp. 1122-1130 ◽  
Author(s):  
Zhanpeng Zheng ◽  
Chengjun Wu ◽  
Hengliang Wu ◽  
Jianyong Wang ◽  
Xiaofei Lei
Keyword(s):  
Theoretical Model ◽  
Dynamic Response ◽  
Vibration Isolation ◽  
Passive Control ◽  
Vibration Energy ◽  
Damping Force ◽  
Damping Effect ◽  
Particle Damping ◽  
Vibration Isolation Performance ◽  
Isolation Performance

Nonobstructive particle damping (NOPD) is a novel passive control technology with strong nonlinear-damping. Many scholars put effort into the research on the internal mechanism of NOPD. In contrast, the application of NOPD to engineering has not received much research effort. A theoretical model based on the principle of gas–solid flows, which is employed to evaluate damping effect of NOPD and to predict dynamic response of a machine rack by a co-simulation approach, is established in this paper. In view of the difference between damping effect acting on the lateral and bottom of NOPD holes directly, total damping force is divided into lateral damping force and bottom damping force according to the Janssen theory of stress changed direction. Moreover, NOPD technology is applied to a machine rack for discussing its vibration isolation performance. The results indicate that NOPD technology can suppress the intense vibration, especially between 4000 Hz and 8000 Hz. It is noted that the theoretical model of NOPD can accurately predict the dynamic response of the machine rack with NOPD. The 1/3 Octave vibration energy spectrum indicates that NOPD technics can dissipate the vibration energy of the machine rack at full frequency, especially in 31.5 Hz, and attenuation up to 39.75 dB.

Chest wall and respiratory system mechanics in cats: effects of flow and volume

1988 ◽  
Vol 64 (6) ◽  
pp. 2636-2646 ◽  
Author(s):  
T. Kochi ◽  
S. Okubo ◽  
W. A. Zin ◽  
J. Milic-Emili
Keyword(s):  
Chest Wall ◽  
Time Constant ◽  
Flow Rate ◽  
Respiratory System ◽  
Flow Resistance ◽  
Stress Adaptation ◽  
Inspiratory Flow Rate ◽  
Intrinsic Resistance ◽  
Pressure Losses ◽  
Airway Occlusion

The effects of inspiratory flow rate and inflation volume on the resistive properties of the chest wall were investigated in six anesthetized paralyzed cats by use of the technique of rapid airway occlusion during constant flow inflation. This allowed measurement of the intrinsic resistance (Rw,min) and overall dynamic inspiratory impedance (Rw,max), which includes the additional pressure losses due to time constant inequalities within the chest wall tissues and/or stress adaptation. These results, together with our previous data pertaining to the lung (Kochi et al., J. Appl. Physiol. 64: 441–450, 1988), allowed us to determine Rmin and Rmax of the total respiratory system (rs). We observed that 1) Rw,max and Rrs,max exhibited marked frequency dependence; 2) Rw,min was independent of flow (V) and inspired volume (delta V), whereas Rrs,min increased linearly with V and decreased with increasing delta V; 3) Rw,max decreased with increasing V, whereas Rrs,max exhibited a minimum value at a flow rate substantially higher than the resting range of V; 4) both Rw,max and Rrs,max increased with increasing delta V. We conclude that during resting breathing, flow resistance of the chest wall and total respiratory system, as conventionally measured, includes a significant component reflecting time constant inequalities and/or stress adaptation phenomena.

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