Special Section on the Fluid Mechanics and Rheology of Nonlinear Materials at the Macro, Micro, and Nano Scale

This collection of selected papers are drawn from those presented at the IMECE 2004 in Anaheim, California at the Symposia “Rheology & Fluid Mechanics of Non-linear Materials,” “Advances in Processing Science,” and “Electric and Magnetic Phenomena in Micro and Nano-Scale Systems” sponsored by the Fluids Engineering Division and the Materials Division, as well as the Symposium on “Flows in Manufacturing Processes” held at the 4th JSME-FED Japanese Society of Mechanical Engineers– Fluids Engineering Division of the ASME joint meeting in Hawaii in July 2003. They represent excellent examples of cuttingedge multidisciplinary research. This editorial is accompanied by an addendum, “Current Unanswered Questions and Future Directions.” I asked the authors in this special section to contribute their thoughts on yet unexplored issues they view as important in their respective areas, and they kindly obliged. I am grateful to those who decided to contribute. I learned the usefulness of the platform from my friend, the late Professor Lloyd Trefethen, who put together several very well received unanswered questions sessions during the meetings of the FED. The symposia series centered on the theme of complex fluids developed as an interdivisional effort in the early nineties, and has been sustained primarily by the FED, the Materials Division and, in the early years, the Applied Mechanics Division, with organizing committees led by Dennis Siginer. Symposia focused on Electroheological Fluids, non-Newtonian and viscoelastic fluids, and industrial applications were held at every annual winter meeting of the ASME. A wider scope and a more encompassing recurring theme were embraced in the mid-nineties, and symposia on the “Rheology & Fluid Mechanics of Non-linear Materials” have been held every year since then without interruption. A second symposia series sponsored by the FED and the Materials Division addressing issues on “Electric and Magnetic Phenomena in Micro and Nano-Scale Systems,” of great interest to emerging technologies and to homeland security, was initiated early in this decade by Dennis Siginer and Boris Khusid. Two complementary symposia of interest to industry in materials processing and manufacturing, “Advances in Materials Processing Science” and “Flows in Manufacturing Processes,” have also been organized regularly for several years, the former held during IMECE and the latter during Summer Meetings of the FED. This collection of papers opens with three contributions related to micro and nano scale problems. The first two are concerned with micro fabrication for the manipulation of nanoparticles using dielectrophoresis, and the third looks into optical finishing using magnetorheological jet polishing technology for a peak-to-valley surface accuracy of the order of 30 nm. Riegelman et al. describe their research on the positioning of carbon nanotubes at predetermined locations with the use of dielectric forces and a fabrication technique to construct carbon nanotube based multiwalled fluidic devices. The technique combines dielectrophoretic trapping with photolithography. James et al. present a novel separation device based on “dielectrophoretic gating” to discriminate between biological and non-