Time-Resolved Micro PIV in the Pivoting Area of the Triflo Mechanical Heart Valve

The Lapeyre-Triflo FURTIVA valve aims at combining the favorable hemodynamics of bioprosthetic heart valves with the durability of mechanical heart valves (MHVs). The pivoting region of MHVs is hemodynamically of special interest as it may be a region of high shear stresses, combined with areas of flow stagnation. Here, platelets can be activated and may form a thrombus which in the most severe case can compromise leaflet mobility. In this study we set up an experiment to replicate the pulsatile flow in the aortic root and to study the flow in the pivoting region under physiological hemodynamic conditions (CO = 4.5 L/min / CO = 3.0 L/min, f = 60 BPM). It was found that the flow velocity in the pivoting region could reach values close to that of the bulk flow during systole. At the onset of diastole the three valve leaflets closed in a very synchronous manner within an average closing time of 55 ms which is much slower than what has been measured for traditional bileaflet MHVs. Hot spots for elevated viscous shear stresses were found at the flanges of the housing and the tips of the leaflet ears. Systolic VSS was maximal during mid-systole and reached levels of up to 40 Pa.

Foreign aid : questions on the Central American regional program need to be resolved : report to the Honorable Patrick Leahy, United States Senate /

"B-221422"--P. [1].

Health effects of exposure to herbicide orange in South Vietnam should be resolved : report /

"B-159451."

Small-angle scattering of neutrons in iron /

Work performed at the Argonne National Laboratory.

Lap belt angle measurement in adjustable rear seats: procedure development and vehicle survey. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Oblique angle crash tests of loaded heavy trucks into an instrumented wall. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Reorganization plan no. 6 of 1950. Hearings before the Committee on Expenditures in the Executive Departments, House of Representatives, Eighty-first Congress, second session on H. Res. 522, resolved, that the House of Representatives does not favor the Reorganization plan numbered 6 of 1950 transmitted to Congress by the President on March 13, 1950. March 30, 31, and April 3, 1950.

William L. Dawson, chairman.

Cases in Parliament resolved and adjudged, upon petitions, and writs of error. [1694-1698]

Mode of access: Internet.

Temple of Minerva, exterior sculpture, Apollo of Veii, front angle view

Veii (deserted settlement). Italy; H: 5 ft. 11 in.; terracotta

Virgin and Child, front left angle view

Metalwork, French, 12C; 1 ft. 2 11/64 in.x 4 27/32 in.x 4 39/64 in.; copper: formed, repoussé, engraved, chased, scraped, and gilt; hands cast; champlevé enamel on wood core

Chasse of Champagnat, principal face, angle view

4 7/8 in.x 7 7/16 in.x 3 11/32 in.; copper, engraved and gilt; champlevé ename on wood core

Roll-yaw control at high angle of attack by forebody tangential blowing /

"October 1995."

The alpha angle adjuster /

A device called the alpha angle adjuster has been developed by the Rocky Flats Plant, Division of the Dow Chemical Company, that enables linear measurements to be made perpendicular to almost any curved surface.