Sound sieve lets you choose what to levitate - tech - 20 June 2014 - New Scientist

Sound sieve lets you choose what to levitate - tech - 20 June 2014 - New Scientist: The team etched a thin brass plate with rectangular strips and suspended it in a tank of water. Ultrasound blasted from above sends acoustic waves through the water that cause the plate to resonate with the bottom of the tank. The resulting sound pressure lifts objects placed below the plate according to size and density.

The team sorted small glass beads from larger ones and pulled glass beads away from tin beads of the same size...

Human brain's ultimate barrier to open for first time - health - 18 June 2014 - New Scientist

Human brain's ultimate barrier to open for first time - health - 18 June 2014 - New Scientist: Next is a treatment called high-intensity focused ultrasound. The volunteers will wear a cap that contains an array of transducers that direct ultrasound waves into their brain. Just as the sun's rays can be focused by a magnifying glass, ultrasound waves can be concentrated inside the body to get the microbubbles to vibrate.

The vibrating bubbles will expand and contract about 200,000 times a second, which will force apart the endothelial cells that form the BBB. The idea is that this will allow the chemotherapy drug in the bloodstream to sneak through the gaps in the barrier and into any nearby tumour cells...

Ultrasonic imaging at 1,000 times times higher resolution | KurzweilAI

Ultrasonic imaging at 1,000 times times higher resolution | KurzweilAI: The researchers used a combination of subpicosecond laser pulses and unique nanostructures to produce acoustic phonons... at a frequency of 10 gigahertz (10 billion cycles per second).

By comparison, medical ultrasounds devices today typically reach a frequency of only about 20 megahertz...

“To generate 10 GHz acoustic frequencies in our plasmonic nanostructures we use a technique known as picosecond ultrasonics,” said author are Kevin O’Brien. “Sub-picosecond pulses of laser light excite plasmons which dissipate their energy as heat. The nanostructure rapidly expands and generates coherent acoustic phonons. This process transduces photons from the laser into coherent phonons.”

Unbelievable Display Technology Uses Levitating Particles as Pixels

Unbelievable Display Technology Uses Levitating Particles as Pixels: Researchers actually figured out how to levitate objects using nothing but sound years ago, but to date it's really only been with single particles. This new research, from Yoichi Ochiai, Takayuki Hoshi, and Jun Rekimoto, presented at the annual Siggraph conference, involves hundreds of tiny specks, all strategically arranged in real-time to form images, and even moving animations.

A Startup Plans to Add Feeling to Gesture Control | MIT Technology Review

A Startup Plans to Add Feeling to Gesture Control | MIT Technology Review: For the study, participants placed a hand, palm facing up, on a table below an array of 64 ultrasound transducers set in an eight-by-eight grid...

In one experiment, the ultrasound array focused feedback on 25 different parts of the hand to see if participants could pinpoint differences in where, precisely, they felt the waves. In the second, the array emitted waves in a way meant to feel like a line of continuous motion in a specific direction across the hand...

... research indicated that that the smallest virtual shape people could reliably feel was about two centimeters square.

Scientists twist sound with metamaterials

Scientists twist sound with metamaterials: ...the team reports a simple design for a device, called an acoustic field rotator, which can twist wavefronts inside it so that they appear to be propagating from another direction...

Another surprise the team discovered was that acoustic and electromagnetic rotators can be designed based on the same principles. In this case, the researchers used anisotropic metamaterials, which possess physical properties that differ along different directions.

Whoa: Watch Scientists Use Sound Waves to Make Things Levitate | Wired Design | Wired.com

Whoa: Watch Scientists Use Sound Waves to Make Things Levitate | Wired Design | Wired.com: ...scientists have been experimenting with acoustic levitation for decades, using sound waves to suspend materials in mid-air. What’s new here, though, is the ability to move those materials in three dimensions.

That’s made possible by the unique arrangement of the speakers themselves. Where former setups bounced sound waves off a solid plate, the Tokyo researchers instead use four panels of speakers, all facing each other. These walls combine to create an “ultrasonic focal point,” which can be moved—along with the object trapped in it—by adjusting the output from each speaker array.

Tingly projections make beamed gadgets come alive

Tingly projections make beamed gadgets come alive: Ishikawa's system detects and maps the position of an object 500 times per second and projects an image onto it. It automatically controls a camera's pan and tilt angles to ensure it is locked onto an object no matter how fast it moves...

...The information about the exact location of your hand and the orientation of the projected keypad is fed to a second system, called the Airborne Ultrasound Tactile Display...

The sensation on the hand is generated by sound beamed by 2000 or so ultrasonic wave emitters... The carefully timed and directed sound beams can make any spot vibrate within a given cubic metre.

New metamaterials device focuses sound waves like a camera lens

New metamaterials device focuses sound waves like a camera lens: Artificial structures are created in patterns that bend the acoustic wave onto a single point, and then refocus the acoustic wave into a wider or narrower beam, depending on the direction of travel through the proposed acoustic beam aperture modifier. The acoustic beam aperture modifier is built upon gradient-index phononic crystals, in this case an array of steel pins embedded in epoxy in a particular pattern. The obstacles (steel pins) slow down the acoustic wave speed in order to bend the acoustic waves into curved rays.
According to post-doctoral scholar and the paper's lead author, Sz-Chin Steven Lin, while other types of acoustic metamaterials also could focus and defocus an acoustic beam to achieve beam aperture modification (although prior to this work no such beam modifier has been proposed), their device possesses the advantage of small size and high energy conservation.

Acoustic tweezers capture tiny creatures with ultrasound (w/ Video)

Acoustic tweezers capture tiny creatures with ultrasound (w/ Video): Acoustic tweezers use ultrasound, the same noninvasive technology doctors use to capture images of the fetus in the womb. The device is based on piezoelectric material that moves when under an electrical current. The vibrations pass through transducers attached to the piezoelectric substrate, where they are converted into standing surface acoustic waves (SAWs). The SAWs create pressure fields in the liquid medium that hold the specimen...
"We believe the device can be easily manufactured at a cost far lower than say, optical tweezers, which use lasers to manipulate single particles," said Tony Jun Huang, associate professor of bioengineering, whose group pioneered acoustic tweezers. "Optical tweezers require power densities 10,000,000 times greater than our acoustic tweezers, and the lasers can heat up and damage the cells, unlike ultrasound."

colloidaldisplay

colloidaldisplay: We developed an ultra thin and flexible BRDF screen using the mixture of two colloidal liquids. There have been several researches on dynamic BRDF display in the past. However, our work is different in several points. Our membrane screen can be controlled using ultrasonic vibrations. Membrane can change its transparency and surface states depending on the scales of ultrasonic waves. Based on these facts, we developed several ap- plications of the membranes such as 3D volume screen.
The combination of the ultrasonic waves and ultra thin membranes makes more realistic, distinctive, and vivid imageries on screen. This system contributes to open up a new path for display engineering with sharp imageries, transparency, BRDF and flexibility.

Sound-cloaking acoustic metamaterials are on the way

Sound-cloaking acoustic metamaterials are on the way: In the latest development, researchers have shown how creating materials that have meandering paths for sound waves can result in a negative acoustic index of refraction.

More importantly, these materials may actually be manufacturable and work for sound waves in air — the stuff we might consider noise.

BBC News - Dr Who's sonic screwdriver 'invented' at Dundee University

BBC News - Dr Who's sonic screwdriver 'invented' at Dundee University: The Dundee University researchers have created a machine which uses ultrasound to lift and rotate a rubber disc floating in a cylinder of water.

It is said to be the first time ultrasound waves have been used to turn objects rather than simply push them...


They used energy from an ultrasound array to form a beam that can both carry momentum to push away an object in its path and, by using a beam shaped like a helix or vortex, cause the object to rotate.

Engineers use short ultrasound pulses to reach neurons through blood-brain barrier

Engineers use short ultrasound pulses to reach neurons through blood-brain barrier: Up until now, scientists have thought that long ultrasound pulses, which can inflict collateral damage, were required. But in this new study, the Columbia Engineering team show that extremely short pulses of ultrasound waves can open the blood-brain barrier -- with the added advantages of safety and uniform molecular delivery -- and that the molecule injected systemically could reach and highlight the targeted neurons non invasively...
Konofagou and her team have designed a focused ultrasound method that can target only the area of the hippocampus that is affected in early Alzheimer's. In this study, they administered microbubbles to enhance the intended mechanical effect, and a high-field MRI to detect and map the area of BBB opening as well as quantify the permeability of the opened BBB...
The blood-brain barrier has been shown to recover within the range of three hours to three days depending on the aforementioned parameters used...

One Per Cent: Programmable friction makes touchscreens sticky

One Per Cent: Programmable friction makes touchscreens sticky: The friction adjustment is actually something of a trick. The surface of the screen itself is made of glass and does not become rougher or smoother. Instead, the glass is made to vibrate at around 26,000 Hz by a series of small mechanical discs that sit at the edge of the screen. This creates a thin film of moving air on top of the glass, which has the effect of making the screen feel slippier. By adjusting the vibrations in response to finger movements across the glass, the system can create a convincing illusion in which objects appear to bump into each other or stick to things.

Opening Up the Brain with Ultrasound - Technology Review

Opening Up the Brain with Ultrasound - Technology Review: Ultrasound has been investigated for a decade as a tool for opening the blood-brain barrier. Most techniques, however, rely on specialized equipment to focus the ultrasound waves to a tiny point. They also require an injection with microbubbles to amplify the effect, and an MRI machine to guide the treatment. Al Kyle, president and CEO of Perfusion Technology, which is based in Andover, Massachusetts, says that the company's method is simpler and cheaper. Rather than opening the blood-brain barrier briefly at a single point, Perfusion uses a specially designed headset to expose the entire brain to low-intensity ultrasound waves for an hour-long treatment session.

Mind controls: Good vibrations reach deep in the brain - health - 14 April 2011 - New Scientist

Mind controls: Good vibrations reach deep in the brain: The sound waves could be focused on an area of 1 to 3 cubic millimetres, similar to electrical deep brain stimulation. And the team targeted an area deep in the brain without affecting overlying tissue, by using several beams to converge on the right spot.

Neurons don't communicate using sound waves, so how does it work? Tyler's best guess is that the force of the sound waves knocks open the neurons' ion channels, which normally trigger electrical firing.

Ultrasound beam lets scientists see deep into human tissue | KurzweilAI

Ultrasound beam lets scientists see deep into human tissue | KurzweilAI: Wang’s guide star is an ultrasound beam that “tags” light that passes through it. When it emerges from the tissue, the tagged light, together with a reference beam, creates a hologram.

When a “reading beam” is then shown back through the hologram, it acts as a time-reversal mirror, creating light waves that follow their own paths backward through the tissue, coming to a focus at their virtual source, the spot where the ultrasound is focused.