| 1. |
- Kirişli, Hortense, et al.
(författare)
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Standardized evaluation framework for evaluating coronary artery stenosis detection, stenosis quantification and lumen segmentation algorithms in computed tomography angiography
- 2013
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Ingår i: Medical Image Analysis. - : Elsevier. - 1361-8415 .- 1361-8423. ; 17:8, s. 859-876
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Tidskriftsartikel (refereegranskat)abstract
- Though conventional coronary angiography (CCA) has been the standard of reference for diagnosing coronary artery disease in the past decades, computed tomography angiography (CIA) has rapidly emerged, and is nowadays widely used in clinical practice. Here, we introduce a standardized evaluation framework to reliably evaluate and compare the performance of the algorithms devised to detect and quantify the coronary artery stenoses, and to segment the coronary artery lumen in CIA data. The objective of this evaluation framework is to demonstrate the feasibility of dedicated algorithms to: (I) (semi-)automatically detect and quantify stenosis on CIA, in comparison with quantitative coronary angiography (QCA) and CIA consensus reading, and (2) (semi-)automatically segment the coronary lumen on CIA, in comparison with expert's manual annotation. A database consisting of 48 multicenter multivendor cardiac CIA datasets with corresponding reference standards are described and made available. The algorithms from 11 research groups were quantitatively evaluated and compared. The results show that (1) some of the current stenosis detection/quantification algorithms may be used for triage or as a second-reader in clinical practice, and that (2) automatic lumen segmentation is possible with a precision similar to that obtained by experts. The framework is open for new submissions through the website, at http://coronary.bigr.nl/stenoses/.
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| 2. |
- Domitner, J., et al.
(författare)
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Characterization of wear and friction between tool steel and aluminum alloys in sheet forming at room temperature
- 2021
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Ingår i: Journal of Manufacturing Processes. - : Elsevier. - 1526-6125. ; 64, s. 774-784
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Tidskriftsartikel (refereegranskat)abstract
- This work investigates the coefficient of friction (COF) at room temperature between tool steel 1.2343 and aluminum alloys EN AW-5182, EN AW-6016 as-delivered (T4) and EN AW-6016 naturally aged (T4*) using a strip drawing tribometer. In order to simulate the contact conditions of industrial sheet metal forming processes, the surfaces of the steel pins and of the aluminum strips were maintained as-delivered, i.e., the pins were wire-cut from a hardened and ground plate and the strips were cut from electrical discharge textured (EDT) and dry-lubricated sheets. Two sliding velocities, 50 mm/s and 250 mm/s, and two nominal contact pressures, 10 N/mm2 and 20 N/mm2, were considered. The sliding distance on each strip was 0.5 m. Each pair of pins was utilized for testing 10 or 20 strips to study the influence of increasing the sliding distance on the COF. Before and after the tribological experiments, surface topographies of selected pins and strips were analyzed using 3D optical surface profilometry, optical microscopy and scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS). Strain hardening due to plastic surface deformation of the strips was investigated using an automated hardness tester. In general, an increasing trend of the COF was observed with increasing sliding distance. The mean COF obtained for each of the tests was in the range of 0.09−0.17; however, it was considerably higher if aluminum was transferred from the strip to the pins. Moreover, moist pin surfaces were identified to increase the COF, as the originally dry lubricant became pasty and sticky which promoted entrapment of abraded aluminum particles. Slightly higher strain hardening of alloy EN AW-5182 compared to alloy EN AW-6016 caused less flattening of the strip asperities and more severe wear of the pin surface.
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