tailieunhanh - Ebook Fundamentals and applications of microfluidics (2nd edition): Part 2

(BQ) Part 2 book "Fundamentals and applications of microfluidics" has contents: Microfluidics for life sciences and chemistry - Microneedles; microfluidics for life sciences and chemistry - Micromixers; microfluidics for life sciences and chemistry - Microdispensers; microfluidics for life sciences and chemistry - Microfilters and microseparators; microfluidics for life sciences and chemistry - Microreactors. | Chapter 7 Microfluidics for Internal Flow Control: Micropumps The next active components of a microfluidic system are micropumps. With the growing importance of genomics, proteomics, and the discovery of new drugs, controlled transport of fluids in microscale becomes an important and crucial task. New transport effects, such as electrokinetic effects, interfacial effects, acoustic streaming, magnetohydrodynamic effects, and electrochemical effects, which previously were neglected in macroscopic applications, now gain in importance on the microscale. Overviews on micropumps were reported in several excellent review papers. Gravesen et al. gave a general overview on fluidic problems in the microscale [1]. Shoji and Esashi discussed microfluidics from the device point of view, and considered micropumps, microvalves, and flow sensors [2]. This chapter only deals with micropumps, and discusses their design considerations as well as the published design examples. In contrast to other MEMS devices, micropumps are one of the components with the largest variety of operating principles. The most important actuation principles are discussed in Chapter 6. Thus, in this chapter micropumps are categorized according to their pumping principles. Similar to other MEMS applications, the first approach in designing a micropump is the miniaturization of well-known mechanical principles from the macroscale. The next approaches were to apply new pumping effects, which are more effective on the microscale than the macroscale. Most of the micropumps developed with the latter approach are nonmechanical pumps. Therefore, micropumps are categorized in this chapter as either mechanical pumps or nonmechanical pumps. Mechanical pumps can be further categorized according to the principles by which mechanical energy is applied to the fluid. Under this system, mechanical pumps are divided into two major categories: displacement pumps and dynamic pumps [3]. In displacement pumps, energy is .