The online Popular Mechanics magazine has an interesting article on The Rise of the Fake Engine Roar. Those that have followed the history of active noise control will remember that Lotus created an acoustic system to create fake engine noise inside the cabin of automobiles to enhance the psychoacoustics perception of engine noise for passengers.
Acoustic Cloaking Device
Researchers at Duke University have shown both theoretically and experimentally a device that is capable of providing acoustic ‘cloaking’ at frequencies between 1kHz-4kHz. The demonstration works for very directional sound waves.
More information can be found on the BBC News web site.
Better MRIs using Low Frequency Noise
Researchers at Minnesota’s Mayo Clinic have developed a technique that uses low frequency sound to vibrate internal organs and when used with a Magnetic Resonance Imaging scanner (MRI) can be used to determine the elasticity or stiffness of internal organs, which is an indicator that something is wrong.
This new technique, called magnetic resonance elastography (MRE), was commercialised by GE Healthcare. They released their new device called MR-Touch, which is the first commercial application of MRE technology, which the company has licensed from the Mayo Clinic.
To read more about this story visit the Scientific American web site.
Ultrasonic
Researchers at Cornell University have developed a portable high intensity ultrasound system. They have built a small battery powered demonstration device.
For more information, read their journal article, “Development of a portable therapeutic and high intensity ultrasound system for military, medical, and research use“
Automotive acoustic liners made from recycled materials
Federal Mogul have developed an acoustic liner that is made from recycled materials including cardboard, carpet fibres, and other fabrics. The first application will be the 2010 Buick LaCrosse luxury sedan.
For more information, read the press release on the Federal Mogul web site.
Conference on Energy Harversting
A conference is currently underway on the topic of Energy Harvesting from sources such as vibration, wind, sun and others.
The Energy Harvesting Journal has a good commentary on the conference with extracts from experts in the field.
Land mine detection using laser vibrometer
Raytheon has won a $US19m contract from the US Defense Advanced Research Projects Agency to develop a vehicle mounted land mine detection system that uses a laser radar vibration sensor.
For more information read the news release on the Raytheon web site.
Brain function alterations from hand-vibration
Researchers have found using Functional MRI scans that the brain function is altered in patients with Hand-Vibration syndrome compared with a control group. The results were presented at the 63rd Annual Meeting of the American Society for Surgery of the Hand. 18-20 September 18-20, 2008. Chicago, USA.
Read the full article on the Orthosupersite.
US federal court blocks active sonar testing
A federal appeals court in the USA (9th Circuit Court of Appeals) has rejected the Bush administration request to exempt the US Navy training activities using active sonar from environmental laws. This decision follows from a lower court that set conditions in an effort to protect whales and dolphins from the active sonar.
Read more on the LA times web site.
New Sony Headphones
Sony have released a new type of headphone that has a separate bass ‘duct’, a tube that is inserted into the ear canal, and external speakers for the mid- and high- frequencies. The PFR-V1 headphones will be available for retail sale in the US in April. The reason for doing this is to provide a more natural sound rather than the ‘in the head’ sound from most headphones. Images of the headphones can be viewed on Sony’s Japan web site.