Blood flow rheology

Hartman A, Dettmers C, Schott H, Beyenburg S. Cerebral blood flow and rheologic alterations by hyperosmolar therapy in patients with brain oedema. Acta Neurochir Suppl (Wein) 1990 51 168-169. 

There are three chapters in this volume, two of which address the microscale. Ploehn and Russel address the Interactions Between Colloidal Particles and Soluble Polymers, which is motivated by advances in statistical mechanics and scaling theories, as well as by the importance of numerous polymeric flocculants, dispersants, surfactants, and thickeners. How do polymers thicken ketchup Adler, Nadim, and Brenner address Rheological Models of Suspensions, a closely related subject through fluid mechanics, statistical physics, and continuum theory. Their work is also inspired by industrial processes such as paint, pulp and paper, and concrete and by natural systems such as blood flow and the transportation of sediment in oceans and rivers. Why did doctors in the Middle Ages induce bleeding in their patients in order to thin their blood ... 

We believe that the development of a successful synthetic graft to replace the smaller arteries of the body will be achieved only when there is a fuller understanding of the rheology of natural arteries and of the haemodynamics of blood flow within them. With this information it should be possible truly to design a successful synthetic replacement with matching rheological and haemodynamic charcteristics. 

The review deals with applications of magnetic resonance imaging (MRI) techniques to study flow. The principles of flow measurement by MRI are first briefly discussed and give examples of some applications, such as multiphase flows, the MRI rheology of complex fluid flows, and blood flows in the human body. 

S.S. Shibeshi and W. E. Colhns, The rheology of blood flow in a branched arterial system, Appl Rheol. 15,398-405 (2005). 

The rheology of blood flow is complex. The specific gravity of plasma and red cells is 1.03 and 1.10, respectively. Blood plasma is a Newtonian fluid with a viscosity equal to 0.00012 Pa s. Whole blood is a non-Newtonian fluid with a viscosity that depends on the shear rate, hematocrit, and temperature. Experimental data on the variation of the viscosity of blood as a function of shear rate for different hematocrits... 

Detailed treatments of the rheology of various dispersed systems are available (71—73), as are reviews of the viscous and elastic behavior of dispersions (74,75), of the flow properties of concentrated suspensions (75—82), and of viscoelastic properties (83—85). References are also available that deal with blood red ceU suspensions (69,70,86). 

Sometimes, cellular analysis was performed with cells in a flow stream, which is also termed flow cytometry or FACS in the field of cell biology. For instance, human blood cell (WBC, RBC) rheology was studied in channels fabricated on the Si-Pyrex substrates. The channels were either uncoated or coated with albumin [825]. 

Suspensions or dispersions of particles in a liquid medium are ubiquitous. Blood, paint, ink, and cement are examples that hint at the diversity and technological importance of suspensions. Suspensions include drilling muds, foodstuffs, pharmaceuticals, ointments and cremes, and abrasive cleansers and are precursors of many manufactured goods, such as composites and ceramics. Control of the structure and flow properties of such suspensions is often vital to the commercial success of the product or of its manufacture. For example, in consumer products, such as toothpaste, the rheology of the suspension can often determine consumer satisfaction. In ceramic processing, dense suspensions are sometimes molded (Lange 1989) and then dried and sintered or fired into optical components, porcelin insulators, turbine blades, fuel cells, and bricks (Rice 1990 Simon 1993). Crucial to the success of the processing is the ability to transform a liquid, moldable suspension into a solid-like one that retains its shape when removed from the mold. These examples could be multiplied many times over. 

---