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The unsteady flow of blood through stenosed artery, driven by an oscillatory pressure gradient, is studied. An appropriate shape of the time-dependent stenoses which are overlapped in the realm of the formation of arterial narrowing is constructed mathematically. A msathematical model is developed by treating blood as a non-Newtonian fluid characterized by the Oldroyd-B and Cross models. A numerical scheme has been used to solve the unsteady nonlinear Navier-stokes equations in cylindrical coordinate system governing flow, assuming axial symmetry under laminar flow condition so that the problem effectively becomes two-dimensional. Finite difference technique was used to investigate the effects of parameters such as pulsatility, non-Newtonian properties and the flow time on the velocity components, the rate of flow, and the wall shear stress through their graphical representations quantitatively at the end of the paper in order to validate the applicability of the present improved mathematical model under consideration.

Blood plasma separation from undiluted blood is an essential step in many diagnostic procedures. This study focuses on the numerical optimization of the microfluidic blood plasma separator (BPS) and experimental validation of the results to achieve portable blood plasma separation with high purity and reasonable yield. The proposed design has two parts: a microchannel for blood processing and a tank, below the aforementioned main channel, for plasma collection. The study uses 3D computational fluid dynamic analysis to investigate the optimal ratio of heights between the top microchannel and the tank and their geometry at various flow rates. Thereafter, the results are compared with the experimental findings of the fabricated devices. These results are put in contrast with some recent reported works to verify the proposed device's contribution to the improvement of quality and quantity of the extracted plasma. The optimized design is capable to achieve a 19% yield with a purity of 77.1% and depending on the requirement of the point-of-care (POC) application. These amounts could be tuned for instance to 100% pure plasma, but the yield would decrease to 9%. In this study the candidate application is hemostasis, therefore, the BPS is integrated to a biomimetic surface for hemostasis evaluation near the patients.Received: ((will be filled in by the editorial staff)) Revised: ((will be filled in by the editorial staff))

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