Tech Briefs Magazine - July 2021 - 32

Manufacturing &
Prototyping
washed away when it comes into contact
with water. Metal-based aerogels are also
suitable as fire-retardant boards, thermal
insulation materials in buildings and
piping systems, for absorption of airborne
contaminants for indoor environments,
and oil spill cleaning.
The metal-based aerogels have high thermal and mechanical stability and could potentially be used
as lightweight building materials and for growing cells for biomedical purposes.
stage, translucent aluminum aerogels
can be created that, as building materials,
can improve natural lighting, reduce
energy consumption for lighting, and
illuminate dark or windowless areas.
Translucent concrete can also be used to
construct sidewalks and speed bumps
that light up at night to improve safety
for pedestrians and road traffic.
When coated with a chemical called
methyltriethoxysilane (MTEOS), aluminum
aerogels can repel water and be -
come a self-cleaning construction material
that allows dirt or debris to be easily
Aluminum aerogels also could be
used as microcarriers for cell cultivation.
Microcarriers are micro-sized
beads on which cells anchor and grow.
To be used as microcarriers, aluminum
aerogels are ground into powder and
added to the mixture of cells and
growth media (including nutrients,
antibiotics, and growth supplements).
The cells are cultivated at 37 °C in an
incubator for 12 days. The microcarriers
are then re moved and the cells are
harvested for various uses.
In the next phase of research, the
team is looking at developing metalbased
aerogels for applications that
require extremely high temperature tolerance
such as for military applications.
For more information, contact Carolyn
Fong at carolyn@nus.edu.sg; +65 6516 5399.
System for In-Situ Defect Detection in Composites
During Cure
This system enhances processing via real-time, non-destructive defect tracking.
Langley Research Center, Hampton, Virginia
T
ypically, non-destructive evaluation
of composites - by ultrasound or
other means - is conducted either
before or after the cure process but
many defects vanish and form during
cure. NASA Langley Research Center,
in collaboration with Analytical Me -
chanics Asso ciates, developed an automated
ultrasonic scanning system for
in-situ cure monitoring and defect
detection of composites in an autoclave
or an oven.
The non-destructive system consists of
an ultrasonic, portable, automated Cscan
system with an attached ultrasonic
contact probe. The scanner is placed
inside an insulated vessel that protects
the temperature-sensitive components
of the scanner. A liquid nitrogen cooling
system keeps the interior of the vessel
below 38 °C. A motorized X-Y raster
scanner is mounted inside an unsealed
cooling container made of porous insulation
boards with a cantilever scanning
arm protruding out of the cooling container
through a slot.
32
Cov
Sealant
Tape
Release Film Bleeder Vacuum Bag Caul Plate
Midpoint
(0mm)
Ply-drop Start
(140mm)
Ply-drop End
(279 mm)
Caul Plate
Edge (375
mm)
The system for in-situ defect detection in composites during cure. (Image: NASA)
The cooling container that houses the
X-Y raster scanner is periodically cooled
using a liquid nitrogen (LN2) delivery system.
Flexible bellows in the slot opening
of the box minimize heat transfer
between the box and the external autowww.techbriefs.com
ToC
clave
environment. The box and scanning
arm are located on a precision cast tool
plate. A thin layer of ultrasonic couplant is
placed between the transducer and the
tool plate. The composite parts are vacuum
bagged on the other side of the tool
Tech Briefs, July 2021
Panel Edge
(381mm)
Composite Panel
(Not to scale)
Transducer
Glycerin Couplant
Tool Plate
Zyvax Coating
4 Plies on Tool Side
24 Taper Plies
4 Plies on Caul Side

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Tech Briefs Magazine - July 2021

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