Mayfly-Mimicking Sensor to Replace Proverbial Canary in the Coal Mine

Bio-inspired engineering research may improve sensors in stagnant environments

COLLEGE PARK, Md., June 19 /PRNewswire-USNewswire/ -- Security, health and
safety sensors in coal mines, buildings or underground public transit areas
where air or water does not readily flow may one day be improved by research
on young mayflies at the University of Maryland's A. James Clark School of
Engineering.

Mechanical engineers Ken Kiger and Elias Balaras and entomologist Jeffrey
Shultz at the University of Maryland have identified a biological mechanism in
the young mayflies that could enable sensors in stagnant environments to make
air or water flow past them so they can detect harmful substances.

Young aquatic mayflies, or "nymphs," enhance their respiration using gills.
They do this by creating a flow of fresh water with the help of seven pairs of
nearby gill plates that flap like a Venetian blind. The flow of fresh water is
generated by the plate's motion, directing water to the mayfly's gills as
efficiently as possible.

"By duplicating the action of the mayfly gill plates in a tiny robotic device,
we hope to create a flow of air or water to sensors in stagnant environments,
so they can operate more effectively," Kiger said.

Working with the University's Department of Entomology, Kiger, an associate
professor of mechanical engineering, is exploring how the mayfly's gill plates
work, and how to make a robotic version. The researchers are currently
duplicating and measuring the gill plate movement in a virtual computer model.

The researchers are also taking a closer look into something that scientists
have known for a long time: at a sufficiently small size, an object is less
affected by inertia than it is by the thickness (viscosity) of the water it is
travelling through.

For example, consider a canoe in comparison to a mayfly. As it travels
through the water, the canoe produces a current, which will continue to ripple
through the water for some time after the canoe moves on. This is an effect of
the water's inertia.

The opposite is true for the tiny mayfly nymph, which is so small that the
thickness (viscosity) of the water stops such a current almost as soon as the
gill plates stop. Once the mayfly grows to a certain size though, it is
capable of creating an inertial effect, or ripples, of its own. Its gills
respond accordingly, which is a trait the researchers hope to replicate in
their sensors.

"Mayfly sizes are right at the point where issues of viscosity and inertia
switch in importance," Kiger said. "Depending on whether the weight or the
thickness of the water is influencing its movement, the mayfly switches the
way it pumps water to its gills."

The current trend in sensor technology is to strive for smaller and more
compact devices to enhance their portability and reduce power consumption. As
a result of this trend, traditional technology sensors will run into the same
difficulty as experienced by the mayfly as the sensors reach smaller and
smaller sizes: eventually a transition will occur where inertial flow
mechanisms will become ineffective. Studying how the mayfly deals with this
transition can give us insight into how to better develop equivalent
engineered sensors.

The next step will be to construct a tiny artificial micro-robot that can
reproduce the switchable gill action of the mayfly nymph. Such a mechanism
could be installed in sensors intended to detect unhealthy air in otherwise
stagnant areas, such as in subway stations or mines. If a miniature set of
robotic mayfly gill plates can move air over a sensor, potentially harmful
substances can be detected faster - and no canaries would be harmed in the
process.

This work is been supported by the National Science Foundation. Entomology
graduate student Andrew Sensenig also contributed to this research.

NOTE TO EDITORS: Images are available with the online version of this release:
http://www.eng.umd.edu/media/pressreleases/pr061908_mayfly.html
Related Links:
Associate Professor Ken Kiger faculty profile:
http://www.enme.umd.edu/facstaff/fac-profiles/kiger.html

About the A. James Clark School of Engineering

The Clark School of Engineering, situated on the rolling, 1,500-acre
University of Maryland campus in College Park, Md., is one of the premier
engineering schools in the U.S.

The Clark School's graduate programs are collectively the fastest rising in
the nation. In U.S. News & World Report's annual rating of graduate programs,
the school is 17th among public and private programs nationally, 11th among
public programs nationally and first among public programs in the mid-Atlantic
region. The School offers 13 graduate programs and 12 undergraduate programs,
including degree and certification programs tailored for working
professionals.

The school is home to one of the most vibrant research programs in the
country. With major emphasis in key areas such as communications and
networking, nanotechnology, bioengineering, reliability engineering, project
management, intelligent transportation systems and space robotics, as well as
electronic packaging and smart small systems and materials, the Clark School
is leading the way toward the next generations of engineering advances.

Visit the Clark School homepage at www.eng.umd.edu.

SOURCE A. James Clark School of Engineering

Missy Corley, +1-301-405-6501, +1-804-398-8652 (cell), mcorley@umd.edu