نتایج جستجو برای: tortuosity

تعداد نتایج: 2064  

2014
Michael Helmberger Michael Pienn Martin Urschler Peter Kullnig Rudolf Stollberger Gabor Kovacs Andrea Olschewski Horst Olschewski Zoltán Bálint

UNLABELLED Pulmonary hypertension (PH) can result in vascular pruning and increased tortuosity of the blood vessels. In this study we examined whether automatic extraction of lung vessels from contrast-enhanced thoracic computed tomography (CT) scans and calculation of tortuosity as well as 3D fractal dimension of the segmented lung vessels results in measures associated with PH. In this pilot ...

2003
L. A. García

Average mass transfer coefficients of an inert compound (LiCl) within denitrifying biofilms were monitored during biofilm growth in a membrane flow cell under different flow conditions, until the biofilm reached (pseudo-) steady state. Average effective diffusivities were found to increase with the decrease in tortuosity factors of the biofilm matrix. The lowest tortuosity factor corresponded t...

Journal: :energy equipment and systems 2015
mohammad riazat majid baniasadi mohsen mazrouie mehdi tafazoli mahdi moghimi zand

in the present study, the effect of porosity on the cathode microstructure (50:50 wt. % lsm: ysz) of a solid oxide fuel cell (sofc) has been examined. a 3-d finite element method for mixed ionic and electronic conducting cathodes (miec) is presented to study the effects of porosity on cell performance. each microstructure was realized using the monte carlo approach with the isotropic type of gr...

Journal: :Interactive cardiovascular and thoracic surgery 2008
Mariano Vicchio Giuseppe Santoro Marianna Carrozza Giuseppe Caianiello

Arterial tortuosity syndrome is a rare connective tissue disorder characterised by elongation, tortuosity, stenosis and aneurysms of the large and middle-sized arteries. The symptomatology is correlated to the artery affected by the pathology with correlated stenosis. We describe our hybrid surgical procedure in the treatment of a case of kinking of the pulmonary branches with significant gradi...

Journal: :Biocybernetics and Biomedical Engineering 2021

Tortuosity in coronary artery has been found to be greatly related the potential sites of stenosis these last years. Many investigations have carried out based on tool Computational Fluid Dynamics (CFD) mainly focusing influences curved blood flow. Within limited coupling between and tortuosity, considered located at tortuous segment. However, with recent clinical studies, case occurred non-tor...

Journal: :Medical image analysis 2002
Conor Heneghan John Flynn Michael O'Keefe Mark Cahill

Many retinal diseases are characterised by changes to retinal vessels. For example, a common condition associated with retinopathy of prematurity (ROP) is so-called plus disease, characterised by increased vascular dilation and tortuosity. This paper presents a general technique for segmenting out vascular structures in retinal images, and characterising the segmented blood vessels. The segment...

2016
B Tjaden

Porous support layers in electrochemical devices ensure mechanical stability of membrane assemblies such as solid oxide fuel cells and oxygen transport membranes (OTMs). At the same time, porous layers affect diffusive mass transport of gaseous reactants and contribute to performance losses at high fuel utilisation and conversion ratios. Microstructural characteristics are vital to calculate ma...

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