Category Physics

Acoustic levitation of a polystyrene sphere, the first spherical object to be acoustically levitated that is larger than the acoustic wavelength. Credit: Andrade et al. ©2016 AIP Publishing

In a new study, researchers have demonstrated the acoustic levitation of a 50-mm (2″) solid polystyrene sphere using ultrasound—acoustic waves that are above the frequency of human hearing. It is one of the first times that an object larger than the wavelength of the acoustic wave has been acoustically levitated. Previously, this has been achieved only for a few specific cases, such as wire-like and planar objects. In the new study, the levitated sphere is 3.6 times larger than the 14-mm acoustic wavelength used here.

“Acoustic levitation of small particles at the acoustic pressure nodes of a standin...

This photograph shows high throughput bioprinting of cells into microwells. Credit: Ozbolat Lab at Penn State

Now that 3D printing has made it easier to generate custom-made prosthetics, bioengineers are looking ahead at manufacturing actual cellular material. Such technology could be the basis for personalized biomedical devices; tissue-engineered skin, cartilage, and bone; or even working bladders. In a Trends in Biotechnology special issue on biofabrication, publishing August 17, researchers review and consider the progress made in 3D bioprinting and what might be possible in the decades — or years — ahead.

1. Made-to-Order Organs-on-a-Chip: inexpensive and efficient personalized medicine...

Circularly polarized light passed through silicon nanorods creates a multilayer image. Lower right inset: SEM image of the material. Credit: WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Silicon holograms harness the full visible spectrum to bring holographic projections one step closer. We can’t yet send holographic videos to Obi-Wan Kenobi on our droid, but researchers at A*STAR, Singapore, have got us a little bit closer by creating holograms from an array of silicon structures that work throughout the visible spectrum.

Many recent advances in hologram technology use reflected light to form an image; however the hologram made by Dong Zhaogang and Joel Yang from the A*STAR Institute of Materials Research and Engineering uses transmitted light...

Atmospheric-pressure (left) and high-pressure (right) 2D layered Lawrencite-type crystal structures of magnesium chloride. Blue and green spheres indicate magnesium cations and chlorine anions respectively. Credit: Image courtesy of Lawrence Livermore National Laboratory

High-pressure structural behavior of magnesium chloride could work to neutralize biological weapons. Lawrence Livermore National Laboratory scientists have combined X-ray diffraction and vibrational spectroscopy measurements together with first-principle calculations to examine the high-pressure structural behavior of magnesium chloride.

Magnesium chloride (MgCl2) is well known to be an effective de-icing agent, for example, in the aviation industry...