| 1. |
- Rezazadeh, M. R., et al.
(författare)
-
A quasi-realistic computational model development and flow field study of the human upper and central airways
- 2024
-
Ingår i: Medical and Biological Engineering and Computing. - : Springer Science and Business Media Deutschland GmbH. - 0140-0118 .- 1741-0444.
-
Tidskriftsartikel (refereegranskat)abstract
- The impact of drug delivery and particulate matter exposure on the human respiratory tract is influenced by various anatomical and physiological factors, particularly the structure of the respiratory tract and its fluid dynamics. This study employs computational fluid dynamics (CFD) to investigate airflow in two 3D models of the human air conducting zone. The first model uses a combination of CT-scan images and geometrical data from human cadaver to extract the upper and central airways down to the ninth generation, while the second model develops the lung airways from the first Carina to the end of the ninth generation using Kitaoka’s deterministic algorithm. The study examines the differences in geometrical characteristics, airflow rates, velocity, Reynolds number, and pressure drops of both models in the inhalation and exhalation phases for different lobes and generations of the airways. From trachea to the ninth generation, the average air flowrates and Reynolds numbers exponentially decay in both models during inhalation and exhalation. The steady drop is the case for the average air velocity in Kitaoka’s model, while that experiences a maximum in the 3rd or 4th generation in the quasi-realistic model. Besides, it is shown that the flow field remains laminar in the upper and central airways up to the total flow rate of 15 l/min. The results of this work can contribute to the understanding of flow behavior in upper respiratory tract. Graphical Abstract: (Figure presented.)
|
|
| 2. |
- Sadiq, Sakar, et al.
(författare)
-
Mechanism of Haibat Sultan Mountain Landslide in Koya, North Iraq
- 2016
-
Ingår i: Engineering. - : Scientific Research Publishing, Inc.. - 1947-3931 .- 1947-394X. ; 8:8, s. 535-544
-
Tidskriftsartikel (refereegranskat)abstract
- Haibat Sultan Mountain is a long range with elevation of about 860 m (a.s.l.); the PilaSpi Formation forms its carapace in Koya vicinity, with relief difference of about 300 m from Koisanjaq plain. The PilaSpi Formation consists of well thickly to massively bedded dolostone and dolomitic limestone with thickness of about 120 m in Koya vicinity. The main trend is NW - SE being a limb of Bustana anticline representing part of the southwestern limb, with dip amount that ranges from (15 - 30). On 11th of November 2015 a landslide had occurred after a heavy rainfall along Koya - Dukan main road. The type of the slide was plane sliding due to daylight slope, which was formed afterthe road cut. The length of the slide area: along the road is 90 m with height of 40 m forming almost a parallelogram shape; the thickness of the slid beds is about 2.5 m. The estimated volume of the slid mass is 9000 m3. The main cause of the landslide is the presence of daylight slope, high slope angle; more than the dip angle, presence of old crack surfaces which are filled by reddish brown clayey residual soil. After the he heavy rain fall, which lasted for 20 hours, the infiltrated rain water in the bedding planes in the well bedded, cracked, and jointed beds has increased the pore pressure and decreased the internal friction angle; therefore, the sliding has occurred. The root of the slid mass is below the base of the paved road; therefore, that part which is above the paved road has slid. The remaining part is highly cracked and partly accumulated in the base of the slid mass. Fortunately, the height of the slid mass is only 40 m and the relief difference between the crown area and the toe area is about 50 m; otherwise the slid mass would be larger than the present slid mass. From the field inspection, it is very clear that the involved area is very unstable and in critical equilibrium. The presence of daylight bedding above the crown area, clayey soil in the fractures and open joints and steep slope all are very favorable conditions for triggering the unstable slope, consequently developing of another landslide with larger mass.
|
|
