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Ultrasonic waves make nimble hands for microscopic tasks
Researchers from the Universities of Bath, Bristol,
and Dundee, all in the UK, discovered that ultrasonic
waves can be used to grab several microparticles at a
time, essentially creating a pair of invisible “ultrasonic
hands” that can move tiny objects, such as cells, under
a microscope. Using plastic spheres the size of biologi-
cal cells, objects could be moved along independent
paths and then carefully brought together. These capa-
bilities provide new tools to study cells that could help
biologists and medical personnel perform a variety of
delicate tasks such as sorting or assembling cells into
patterns for tissue engineering, stem cell work, and regenerative medicine.
“Sophisticated microparticle manipulation is possible using a relatively simple desktop
apparatus that can be used with a standard microscope system. We believe this has the po-
tential to radically improve results in bioscience labs where pinpoint positioning of cells is
a useful research tool,” says Charles Courtney of the University of Bath’s mechanical engi-
neering department. .
Multiscale modeling project targets aerospace costs
The EU CRASHING project, funded by the Clean Sky Joint Technol-
ogy Initiative (JTI-Clean Sky) within the EU’s 7th Framework Program,
aims to develop new methods of testing aerospace materials through
multiscale computer simulation to save time, money, and lives. The two-year project will
address costs by building on recent progress in multiscale modeling. CRASHING focuses
on composite materials used in current aircraft design, as well as innovative materials with
potential future applications.
Computer models will provide accurate simulations of what happens when an aircraft
crash lands, is hit by ice, or is exposed to other extreme impacts. Hopefully CRASHING
will lead to a significant reduction in the number of physical tests required for aircraft cer-
tification and reduce development time for new structural components. The project is
being led and coordinated by the IMDEA Materials Institute in Spain, which is responsi-
ble for development and validation of multiscale models at different levels. The other con-
sortium partner, Carlos III University of Madrid, is in charge of experimental
characterization of materials under impact. .
Rotational x-ray tracking opens up new class of materials
Over the past 20 years, there has been increasing interest and development in
measuring slow dynamics in disordered systems at the nanoscale. Some
techniques developed during recent years to study the dynamic proper-
ties of these materials include x-ray photon correlation spectroscopy
(XPCS) and speckle visibility spectroscopy (SVS). However, both
techniques are limited in that they require specialized x-ray
facilities and nanoscale resolution.
Scientists at the University of Illinois at Urbana-
Champaign, Argonne National Lab, Centre for Free-Electron Laser Sci-
ence, Germany, and University College London, UK, developed a new
technique called rotational x-ray tracking (RXT). The technique was used
to study small crystalline particles that become immobilized when they
form a colloidal gel under certain conditions. Instead of characterizing the gel as an immo-
bile colloidal dispersion, scientists showed how particles in the gel actually undergo angu-
lar motion. The precise nature of the rotational motion uniquely measures the nanoscale
elastic properties of the gel network. These findings open up an entirely new class of dy-
namic systems and materials, according to researchers. .
briefs
The Innovative Technology
Partnerships Office at NASA
Goddard Space Flight Center,
Greenbelt, Md., will
collaborate with Rolls-
Royce, Indianapolis, to
develop braze joint
performance prediction
methods for critical structures
subject to complex loading
conditions. Rolls-Royce will
establish a braze failure
assessment diagram (FAD) that
can be used to define acceptable
stress combinations and margins
of safety for braze joints and braze
repair structures. NASA will receive
verification of its FAD methodology
for failure prediction of structural
brazed joints on actual industrial
applications.
.
Submissions are welcome for the
Buehler Microstructure of
Materials Calendar 2015, with
publication open to anyone who
has achieved a level of excellence
in materials preparation.
Photomicrographs can include
microstructural details or hardness
indents of any metallic,
nonmetallic, geological, or bio-
related materials. Images must be
obtained through a light optical
microscope or hardness tester and
cannot be digitally colored or
enhanced. Selected entries will
receive an honorarium of $200.
Submission deadline is July 31. For
more information: 847.295.6500,
.
WuXi PharmaTech Inc., Shanghai,
expanded its materials
characterization testing facility in
St. Paul, Minn. The new 20,000-
sq-ft laboratory offers expanded
capacity for existing services, such
as particle identification and
extractable/leachable testing, and
adds a new service—dynamic
light scattering for nanoparticle
characterization. These services
are required by the FDA for filings
of medical devices or biologics.
.
ADVANCED MATERIALS & PROCESSES • JULY 2014 8
TESTING CHARACTERIZATION
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Researchers create ultrasonic
hands that can grip
microparticles. Courtesy of
University of Bath.
Bragg scattering
geometry for the
experiment.
Courtesy of
M.Liang, et al.