Education

• Ph.D., Stanford University, 1993
• M.S., Stanford University, 1987
• B.S., California Institute of Technology, 1985

Background

Dr. Yoda began at Tech in 1995 as an Assistant Professor. Prior she was a Postdoctoral Fellow in the Hermann Foettinger Institute at the Technical University of Berlin, Germany.

Research

• Fluid Mechanics: Experimental fluid mechanics, suspension flows, nano- and microfluids, and optical diagnostics

Dr. Yoda's research is in experimental fluid mechanics and optical diagnostic techniques down to the nanoscale. Recent developments in chemistry and biology have opened up several exciting new opportunities for fluid mechanics to make significant contributions to areas beyond traditional aeronautical and mechanical engineering.

The goal of Dr. Yoda's work in nanofluidic diagnostic techniques is to optimize liquid transport at the submicron scale, a critical technology for the next generation of biochemical microsensors. Electromagnetic forces are the leading method for transporting DNA (for example) to these sensors. Understanding these electrophoretic flows, which are typically 30-400 nm in extent, is required to improve micropump designs. Yet the best resolution of state of the art fluid diagnostic techniques is a few microns. Dr. Yoda's group is therefore developing total internal reflection fluorescence (TIRF) techniques to study flows with an unprecedented spatial resolution of 50-300 nm. The results from this work will be used to fabricate new micropumps with Prof. P.J. Hesketh.

She is also working with Prof. P.H. Rogers on studying flows due to sound in fish ears. Such flows may be the key to how fish determine the direction of oncoming sound. Flows in model fish ear geometries are currently being studied using flow visualization and particle-image velocimetry.

Dr. Yoda's projects in particle-liquid suspension flows investigate how particles interact with solid surfaces. The results will be used to improve polishing processes (such as those used to polish silicon wafers in chip manufacturing) and develop new filtration devices (for reclaiming water and air in space habitats). TIRF is being used to study abrasive particles in water next to a model silicon wafer. This research will lead to better abrasives in chip manufacture by determining how particle properties affect wafer polishing.

Dr. Yoda is working with Prof. S.I. Abdel-Khalik on different protective liquid blanket configurations for inertial fusion energy power plants. With the National Ignition Facility at Livermore National Laboratories scheduled for completion by the end of this decade, the first inertial fusion event will be achieved in the next ten years. Current commercial fusion power plant designs depend upon protective liquid blankets to serve as coolant and shield the reactor chamber walls from the fusion event. Her group is therefore studying both high-speed turbulent sheets and flowing films of water.

Dr. Yoda and Prof. C.K. Aidun are collaborating on flow control schemes to improve paper quality. Paper starts out as a jet of wood pulp fibers suspended in water. The flow properties of this forming jet determine the orientation of these fibers, and hence the mechanical properties of the final paper product. Dr. Yoda is developing adjustable mechanisms that can be retrofitted to existing paper mills to control fiber orientation online.

In the next few years, Dr. Yoda plans to extend her experimental techniques to biomedical and tribological problems. Studying interfaces with submicron resolution would be useful in studying wear and how lubrication failure leads to wear. Current lifetimes of hip prostheses, for example, are limited to a decade because of immunological reactions to the wear debris from the artificial joint. These new techniques could potentially lead to on-line or in vivo fiber-optic sensors for monitoring wear and abrasion in a wide variety of mechanical components, including prostheses, precision bearings, and various types of seals.

Advances in photonics have led to an "explosion" in the use of optical techniques over the last decade in science and engineering. Dr. Yoda's research focuses on continuing to develop these exciting diagnostic techniques and using them to solve fluid mechanics problems for key American industries. Because such problems are inherently multidisciplinary, the graduate students in her group develop a wide variety of skills valuable for their future careers.