Concussion and longer-lasting brain damage caused by the compression waves from explosions are a growing problem for the military. Carbon foam able to absorb a blast could help tackle that.
A team funded by the US Army Space and Missile Defense Command in Huntsville, Alabama, has developed panels of carbon foam with pores varying in size from 50 micrometres to 2 millimetres.
Carbon foam is made by heat-treating particular materials made from carbon fibres. In tests, panels of the foam absorbed up to 83% of the energy of a blast wave from the detonation of 2 kilograms of C4 explosives at a distance of only 20 centimetres.
This is possible because the foam's pores collapse when hit by a compression wave, absorbing its energy.
The team says the material could be used to protect rooms and vehicles and, if used to enclose explosives, could prevent their accidental detonation when caught in a blast.
Read the full explosion-absorbing foam patent application.
Justin Mullins, New Scientist consultant
Archive for the ‘materials’ Category
Explosion-absorbing foam
Thursday, June 12th, 2008Magnetic bone implants
Friday, June 6th, 2008
If the bionic man ever becomes reality, his skeleton may be magnetic.Artificial bone implants can help fix damaged skeletons, but they can also prevent the healthy growth of natural bone around the implant, weakening the bond between them.
Various ways of encouraging growth and preventing infection have been tried – among them impregnating bone implants with growth hormones and using anti-inflammatory drugs and antibiotics. But these methods provide only a single dose of treatment and if the problem recurs there is little that can be done to treat it without surgery.
One possibility is to attach the drug to magnetic particles and steer them through the body to the relevant site using an external magnetic field. But using that field to hold the drug-bearing particles in place for hours or days is impractical.
Making bone implants magnetic, so that the particles simply stick to them, could get around that, says Zachary Forbes, a surgeon at Drexel University College of Medicine in Philadelphia, US.
He adds magnetic powder to the biopolymer used in bone implants so that they can be made magnetic for an extended time, using the same strong magnetic field used to steer drug particles.
Read the full magnetic bone implant patent application.
Justin Mullins, New Scientist consultant
Wallpaper speakers
Tuesday, May 20th, 2008
Microphones and speakers use piezoelectric materials that move in response to voltage, or create voltage from movement. But common piezoelectric materials are expensive, heavy and brittle.
Now materials scientist Michael Yu at Johns Hopkins University in Baltimore and colleagues say they have made a rubbery plastic-based material that could help place piezoelectric devices in previously impractical areas.
The team's invention is based on a polypropylene foam with piezoelectric properties that was discovered in 2004. The plastic is flexible and has entirely different mechanical properties to most other, often crystalline or ceramic, piezoelectric materials.
By adding silicone rubber to that material, Yu and colleagues have made it possible to separately control the material's piezoelectric mechanical properties.
Until now changing the flexibility, say, of a piezoelectric material would always impact its electrical properties. That made it near-impossible to design materials with certain combinations of physical and piezoelectric properties.
Combined with the ease with which polymers can be processed, the new material should open up novel applications: wallpaper that functions as speakers, lightweight devices to scavenge movement energy, and foldable speakers, are just some of their ideas.
Read the full wallpaper speakers patent application.
Justin Mullins, New Scientist consultant
Now materials scientist Michael Yu at Johns Hopkins University in Baltimore and colleagues say they have made a rubbery plastic-based material that could help place piezoelectric devices in previously impractical areas.
The team's invention is based on a polypropylene foam with piezoelectric properties that was discovered in 2004. The plastic is flexible and has entirely different mechanical properties to most other, often crystalline or ceramic, piezoelectric materials.
By adding silicone rubber to that material, Yu and colleagues have made it possible to separately control the material's piezoelectric mechanical properties.
Until now changing the flexibility, say, of a piezoelectric material would always impact its electrical properties. That made it near-impossible to design materials with certain combinations of physical and piezoelectric properties.
Combined with the ease with which polymers can be processed, the new material should open up novel applications: wallpaper that functions as speakers, lightweight devices to scavenge movement energy, and foldable speakers, are just some of their ideas.
Read the full wallpaper speakers patent application.
Justin Mullins, New Scientist consultant
Anti-scar bandage
Friday, May 16th, 2008
Keloid scars are angry red lesions that sometimes form after surgery or injury when the skin "overheals" creating an extra tough region of new skin.
Dermatologists believe that one factor in their formation is stretching during healing caused by the patient moving, or by the tissue beneath swelling.
So Geoff Gurtner and colleagues at the Stanford University Medical Center in California have developed bandages that can prevent this kind of stretching.
Their bandages are made of "shape memory" polymers that set into a rigid shape after being applied to the wound. They are fixed into place using powerful adhesives, or sewn or stapled over the wound during surgery.
The team has tested the idea on mice and says it can significantly reduce the amount of scarring by holding the healing tissue firm.
Read the full anti-scar bandage patent application.
Justin Mullins, New Scientist consultant
Dermatologists believe that one factor in their formation is stretching during healing caused by the patient moving, or by the tissue beneath swelling.
So Geoff Gurtner and colleagues at the Stanford University Medical Center in California have developed bandages that can prevent this kind of stretching.
Their bandages are made of "shape memory" polymers that set into a rigid shape after being applied to the wound. They are fixed into place using powerful adhesives, or sewn or stapled over the wound during surgery.
The team has tested the idea on mice and says it can significantly reduce the amount of scarring by holding the healing tissue firm.
Read the full anti-scar bandage patent application.
Justin Mullins, New Scientist consultant
Nanotube filter
Thursday, May 8th, 2008
Carbon nanotubes are tiny tubes of carbon atoms. When properly formed and lined up, they can be superb conductors or semiconductors, have high thermal conductivity and huge mechanical strength. The versatile structures are touted as being invaluable for everything from space elevators to anti-HIV treatments.
But nanotubes are tricky to control. So far it has only been possible to lay them down at random, which makes exploiting their amazing properties much more difficult.
Now Mary Chan, a chemical engineer at Nanyang Technological University in Singapore has come up with a simple solution.
She suggests suspending the nanotubes in water and passing the fluid through narrow channels. The nanotubes would only be able to pass through the channels if they are aligned with the direction of flow.
When the liquid is drained, the aligned nantotubes settle into place creating a material in which the extraordinary properties of carbon nanotubes can be exploited to the full.
Read the full nanotube filter patent application.
Justin Mullins, New Scientist consultant
But nanotubes are tricky to control. So far it has only been possible to lay them down at random, which makes exploiting their amazing properties much more difficult.
Now Mary Chan, a chemical engineer at Nanyang Technological University in Singapore has come up with a simple solution.
She suggests suspending the nanotubes in water and passing the fluid through narrow channels. The nanotubes would only be able to pass through the channels if they are aligned with the direction of flow.
When the liquid is drained, the aligned nantotubes settle into place creating a material in which the extraordinary properties of carbon nanotubes can be exploited to the full.
Read the full nanotube filter patent application.
Justin Mullins, New Scientist consultant
Plastic red blood cells
Friday, May 2nd, 2008
Red blood cells travel through the bloodstream delivering vital oxygen to body tissues and taking away unwanted carbon dioxide – and they have to squeeze through blood vessels as thin as 3 micrometres across to do it. But in some diseases, such as malaria and sickle cell disease, red blood cells lose this ability to deform.
Because of the small size of red blood cells and the demanding work they do, nobody has succeeded in making artificial versions to help people with such conditions.
Now though Joseph DeSimone, a chemical engineer at the University of North Carolina at Chapel Hill, US, thinks he knows how.
He has created tiny sacks of the polymer polyethylene glycol just 8 micrometres across – in the range of human red blood cells – that are capable of deforming in a way that allows them to pass through the tiniest capillaries.
Polyethylene glycol is biologically benign, but binds easily with other substances, which makes it ideal for carrying cargo through the blood, says DeSimone.
For example, a haemoglobin-type molecule carried inside the bag could deliver oxygen to the body and carry away carbon dioxide. The bags could also deliver drugs instead, or help as contrast agents for scans such as magnetic resonance imaging, PET or ultrasound.
DeSimone has injected the particles into mice with "no adverse side effects", but there is no news yet of more extensive tests.
Read the full plastic red blood cells patent application.
Justin Mullins, New Scientist consultant
Because of the small size of red blood cells and the demanding work they do, nobody has succeeded in making artificial versions to help people with such conditions.
Now though Joseph DeSimone, a chemical engineer at the University of North Carolina at Chapel Hill, US, thinks he knows how.
He has created tiny sacks of the polymer polyethylene glycol just 8 micrometres across – in the range of human red blood cells – that are capable of deforming in a way that allows them to pass through the tiniest capillaries.
Polyethylene glycol is biologically benign, but binds easily with other substances, which makes it ideal for carrying cargo through the blood, says DeSimone.
For example, a haemoglobin-type molecule carried inside the bag could deliver oxygen to the body and carry away carbon dioxide. The bags could also deliver drugs instead, or help as contrast agents for scans such as magnetic resonance imaging, PET or ultrasound.
DeSimone has injected the particles into mice with "no adverse side effects", but there is no news yet of more extensive tests.
Read the full plastic red blood cells patent application.
Justin Mullins, New Scientist consultant