THE COUPLE MOTION BETWEEN VESSEL WALL AN DBLOOD IN THE ENTRANCE REGION OF A TAPERED VESSEL

A problem of couple motion between vessel wall and blood in the entrance regionof a tapered vessel is considered in this paper A mathematical model of co-coupleaction is formed for both motion of vessel wall and blood flow in the entrance regance regionof elastic vessel with tapered angle. Under the situation that the relative boundary conditions are satisfied a.set of velocity distribution formula. pressure distributionformula for the blood flow in a tapered elastic vessel are derived. Some importantconclusions are obtained.

THE STRESS ANALYSIS OF VESSEL WALL IN THE ENTRANCE REGIONOF A TAPERED VESSEL

The present paper deals with the flow in an entrance region of a tapered vessel.Pressure distribution formula . axial and radial distribution formulas,shear stressdistribution formula of.flow field and shear stress distribution formula of vessel wallare derived. Relative numerical computations are made and analyzed.Discussion of the effects of tapered angle on the pressure distribution and vessel wall stress distributionare emphasized.

Taper Angle Correction in Cutting of Complex Micro-mechanical Contours with Ultra-Short Pulse Laser

The objective of this work was to investigate the possibility of taper angle correction in cutting of complex micro-mechanical contours using a TruMicro ultra-short pulse laser in combination with the SCANLAB precSYS micro machining sub system. In a first step, the influence of the process parameters on the kerftaper angle of metallic alloys was systematically investigated without beam inclination. A set of base parameters was derived for the subsequent investigations. In a second step, the kerftaper angle was controlled by static beam inclination. In a third step, the same optics was used in its dynamic precession mode to fabricate micro-mechanical components of complex contours with perpendicular 0~ taper angles. It was found that taper angle adjustments of up to 7.5~ are possible with the used setup for cutting applications. Taper angle control is possible both in the static beam inclination mode and in the dynamic precession mode. The static mode could be interesting for contours with sharp inner radii and for achieving faster cutting times similar to results with fixed optics, but would require excellent synchronization of beam inclination and axis motion. The dynamic precession mode would allow an easier integration of the optics into a laser machine but will result in longer cutting times and limitations with respect to achievable inner radii.

ANALYSIS OF OSCILLATORY BLOOD FLOW IN VARYING-AREA ELASTIC VESSEL

In this paper, by solving the fundamental e-qualions of periodicallyoscillatory blood flow, the distributions of pressure gradient and blood velocity in varying-areae-lastic vessel were obtained, and then the wall shear stress and its gradient were calculated. Asan example, the pulsatile blood flow in human carotid was analyzed and the effects of vessel taperangle on the distribution of wall shear stress and its gradient were discussed in detail. Numercialresults show that the wall shear stress will enlarge when the taper angle increases. Meantime, nomatter whether the vessel is converging or diverging, with the increase of the absolute value oftaper angle, the amplitude of wall shear stress gradient will enlarge significantly.