Peristaltic Transport of a Herschel-Bulkley Fluid in a Non-Uniform Channel with Wall Effects
669 Abstract—The present study considers the peristaltic transport of a Herschel-Bulkley fluid in a two-dimensional channel of non-uniform cross section with wall properties. Using long wavelength approximation with low Reynolds number and dynamic boundary conditions, analytical expressions have been obtained stream function and time average velocity. The effects of pertinent parameters on these flow variables have been studied in both converging and diverging channel. It is observed that time average velocity increases with rigidity and stiffness in the wall.
Magneto hydrodynamic (MHD) peristaltic blood flow of Ree-Eyring fluid in a compliant channel with influence of heat and mass transfer
In the present article, combined effects of magneto hydrodynamics, partial slip, heat and mass transfer in blood flow of Ree-Eyring fluid have been examined. The medium is considered to be porous and the walls of this non uniform porous channel are supposed to be compliant. The governing equations of the obtained mathematical model are simplified by using long wavelength and low Reynolds number approximation. The expressions for axial velocity, temperature distribution, concentration distribution and heat transfer coefficient are examined and discussed through graphs.
Diversity of Electrospinning Approach for Vascular Implants: Multilayered Tubular Scaffolds
Abstract The biomimetics of biological structures found in nature remains one of the most promising approaches to engineer functional tissues from natural or synthetic biocompatible materials for the replacement of damaged or injured parts of the human body. Recently, medical therapeutic regimes have advanced into a new era, overcoming the known mechanical and biological variances that occur when using autologous or synthetic grafts. Basically, the core concept of tissue biofabrication, commonly referred to as tissue engineering, is to find out the favorable cellular microenvironments to grow a living tissue prior to clinical uses. In fact, the ability of stem cells to regenerate is controlled via signaling pathways (growth factors) and supporting materials (scaffolds) that guide the cellular activities. After the first successful experiments to fabricate polymer fibers from their solutions, Cooley proposed the use of an electric field a century ago (Cooley (US 692:631, 1902 ). The electrospinning technique has been continually developed as a fruitful polymer processing technique to draw ultrafine nonwoven fibers. Electrospun polymer fibers have been used for a wide range of technical and biotechnical applications such as filtration, organic solar cells, tissue engineering, and drug releasing implants. In this regard, this review begins with an overview about the various spinning approaches for the fabrication of polymer fibers as well as the basic principles of electrospinning process. In addition, this review will highlight vascular bypass surgery and, in particular, the needs for vascular tissue engineering. Finally, the review includes some of the latest attempts to improve the mechanical and biological properties of electrospun polymeric fibers and summarizes the challenges and prospects for the future. Lay Summary However, vascular defects are treated successfully via bypass surgical bypass grafting using autologous or synthetic vessels. The small-diameter vessels (less than 6) are often associated with high failure rate. This review reports some of the recent features that should be highlighted to fabricate an ideal graft for small-diameter vascular grafts. The review introduces multilayered conduits as an alternative approach to overcome the known mechanical and biological mismatches of single layered vascular grafts of electrospun polymers.