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Deformation of the dog aortic valve ring during the cardiac cycle (1988)

Renterghem, B. J. ; Steenhoven, A. A. ; Arts, T. ; [et al.]

Springer

Pflügers Archiv 412 (1988), S. 647-653

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ISSN: 1432-2013

Keywords: Aortic valve ; Commissure strain ; Base strain ; Commissure-base strain ; Inductive coils

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine

Notes: Abstract Changes in strain in the line of aortic valve leaflet attachment (aortic ring) were measured during the cardiac cycle by means of an inductive technique. To that purpose coils were sutured to each commissure and base point of the aortic ring, when the animals were on a cardiopulmonary bypass. After bypass and stabilization of the hemodynamic variables changes in the aortic strain were measured at aortic pressures ranging from 4 to 20 kPa. Aortic pressure at the level of the commissure points and left ventricular pressure were measured to assess transvalvular pressure. Commissure strain appeared to depend on aortic and transvalvular pressure throughout the cardiac cycle. At an aortic pressure of 10 kPa (75 mm Hg), the derivative of commissure strain to aortic pressure was found to be 1.9×10−5±1.2×10−5 Pa−1 (mean ±SD). During the ventricular ejection phase commissure strain was 0.04±0.03 higher than during ventricular filling. Maximum variations in basal strain during the cardiac cycle ranged from 0.03 to 0.15. During the ejection phase the basal segments adjoining the myocardium shortened whereas the segment close to the non-contracting anterior mitral valve leaflet lengthened. Strain between a base and a commissure point of the aortic ring were synchronous with the cardiac cycle, but no specific pattern could be found.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00583767

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On the consistency of four different control surfaces used for finite area blade-to-blade flow calculations (1984)

Arts, T.

Chichester : Wiley-Blackwell

International Journal for Numerical Methods in Fluids 4 (1984), S. 1083-1095

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ISSN: 0271-2091

Keywords: Turbomachines ; Finite Volume ; Consistency ; Engineering ; Engineering General

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: The aim of this contribution is to investigate the consistency and order of accuracy of different control surfaces used for finite area blade-to-blade flow calculations. The following cases will be treated: a hexagonal element, a trapezoidal element, a bitrapezoidal element and a quadrilateral element. Finally, the consistency conditions will be discussed and compared with respect to a cascade flow application.

Additional Material: 6 Ill.