2009-2010 Bulletin – PDF - SEAS Bulletin - Columbia University

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of energy and environmental systems.
The design and testing of components
and systems for micropower generation
is part of the thermofluids effort as well
as part of the MEMS effort. (Modi)
In the area of fluid mechanics, study
of low-Reynolds-number chaotic flows
is being conducted both experimentally
and numerically, and the interactions
with molecular diffusion and inertia are
presently being investigated. Other areas
of investigation include the fluid mechanics
of inkjet printing, drop on demand,
the suppression of satellite droplets,
shock wave propagation, and remediation
in high-frequency printing systems.
(Attinger, Modi)
In the area of microscale transport
phenomena, current research is focused
on understanding the transport through
interfaces, as well as the dynamics of
interfaces. For instance, an oscillating
microbubble creates a microflow pattern
able to attract biological cells. Highspeed
visualization is used together with
innovative laser measurement techniques
to measure the fluid flow and temperature
field with a very high resolution. (Attinger).
In the area of nanoscale thermal
transport, our research efforts center on
the enhancement of thermal radiation
transport across interfaces separated by
a nanoscale gap. The scaling behavior of
nanoscale radiation transport is measured
using a novel heat transfer measurement
technique based on the deflection
of a bi-material atomic force microscope
cantilever. Numerical simulations are also
performed to confirm these measurements.
The measurements are also used
to infer extremely small variations of van
der Waals forces with temperature. This
enhancement of radiative transfer will ultimately
be used to improve the power
density of thermophotovoltaic energy
conversion devices. (Narayanaswamy)
Research in the area of tribology—the
study of friction, lubrication, and wear—
focuses on studying the wear damage
and energy loss that is experienced in
power generation components such as
piston rings, fuel injection systems,
geartrains, and bearings. Next-generation
lubricants, additives, surface coatings,
and surface finishes are being studied in
order to determine their effects on friction
and wear. Additionally, environmentally
friendly lubricants are also being identified
and characterized. (Terrell)
MEMS and Nanotechnology. In these
areas, research activities focus on power
generation systems, nanostructures for
photonics, fuel cells and photovoltaics,
and microfabricated adaptive cooling
skin and sensors for flow, shear, and
wind speed. Basic research in fluid
dynamics and heat/mass transfer phenomena
at small scales also support
these activities. (Attinger, Hone, Lin,
Modi, Narayanaswamy, Wong)
We study the dynamics of microcantilevers
and atomic force microscope
cantilevers to use them as microscale
thermal sensors based on the resonance
frequency shifts of vibration
modes of the cantilever. Bi-material
microcantilever-based sensors are used
to determine the thermophysical properties
of thin films. (Narayanaswamy)
Research in the area of nanotechnology
focuses on nanomaterials such as
nanotubes and nanowires and their
applications, especially in nanoelectromechanical
systems (NEMS). A laboratory
is available for the synthesis of
carbon nanotubes and semiconductor
nanowires using chemical vapor deposition
(CVD) techniques and to build
devices using electron-beam lithography
and various etching techniques. This
effort will seek to optimize the fabrication,
readout, and sensitivity of these
devices for numerous applications, such
as sensitive detection of mass, charge,
and magnetic resonance. (Hone, Wong,
Modi)
In the area of nanoscale imaging in
biology, a super-resolution microscopy
(nanoscopy) system is built to break the
diffraction limit of light. The super-resolution
microscopy system is to be used to
observe molecular dynamics in living
cells. A high-speed scanning system is
designed and implemented to track
molecular dynamics in a video rate.
Control of sample motion in nanometer
resolution is achieved by integrating single
photon detection and nano-positioning
systems. (Liao)
Research in the area of optical nanotechnology
focuses on devices smaller
than the wavelength of light, for example,
in photonic crystal nanomaterials
and NEMS devices. A strong research
group with facilities in optical (including
ultrafast) characterization, device
nanofabrication, and full numerical intensive
simulations is available. Current
efforts include silicon nanophotonics,
quantum dot interactions, negative
refraction, dramatically enhanced nonlinearities,
and integrated optics. This effort
seeks to advance our understanding of
nanoscale optical physics, enabled now
by our ability to manufacture, design,
and engineer precise subwavelength
nanostructures, with derived applications
in high-sensitivity sensors, highbandwidth
data communications, and
biomolecular sciences. Major ongoing
collaborations across national laboratories,
industrial research centers, and
multiuniversities support this research.
(Wong)
In the area of microscale power generation,
efforts are dedicated to build a
micromotor using acoustic energy amplified
by a microbubble. (Attinger)
Research in the area of microtribology—the
study of friction, lubrication, and
wear at the microscale—analyzes the
surface contact and adhesive forces
between translating and rotating surfaces
in MEMS devices. Additionally, the
tribological behavior between sliding
micro- and nano-textured surfaces is
also of interest, due to the prospects of
enhanced lubrication and reduced friction.
(Terrell)
Research in BioMEMS aims to
design and create MEMS and
micro/nanofluidic systems to control
the motion and measure the dynamic
behavior of biomolecules in solution.
Current efforts involve modeling and
understanding the physics of micro/
nanofluidic devices and systems,
exploiting polymer structures to enable
micro/nanofluidic manipulation, and integrating
MEMS sensors with microfluidics
for measuring physical properties of
biomolecules. (Lin)
Biological Engineering and Biotechnology.
Active areas of research in the
musculoskeletal biomechanics laboratory
include theoretical and experimental
analysis of articular cartilage mechanics;
theoretical and experimental analysis
of cartilage lubrication, cartilage tissue
engineering, and bioreactor design;
growth and remodeling of biological tis-
SEAS 2009–2010