As the science of using sound

Acoustics, dude, not a guitar, not something coming from the subwoofer, causing the collapse of his «seven» part, and the direction that will pull modern science to another level. Well, on the sound, you can build «a garden city». In the meantime, in the present, read an academic article about how now the tricky scientists use sound in their research.

1. Cooling

A team of researchers from the University of Pennsylvania has made a refrigerator that cools the food sound. The principle of operation are simple for everyone who has an idea about physics: sound waves compress and expand the air around them, consequently the air is cooled or expanded. As a rule, sound waves do not affect the temperature of not more than 1/10000 of a degree, but a greater effect can be achieved by placing the gas inside the fridge under a pressure of about 10 atmospheres. The result is a thermoacoustic freezer, which compresses the gas in the cooling chamber and subjected to more than 173 decibels of sound, generating heat.

Inside the metal plates that occur on the way sound waves that absorb heat and transfer it to the heat exchanger system.

The system was developed as a more environmentally friendly alternative to traditional refrigerators. Unlike traditional models that use refrigerants chemical, crook spoil the atmosphere of a thermoacoustic refrigerator works very well with inert gases such as helium. If helium is somewhere implies, it simply returns to the atmosphere. Nothing easier and more environmentally friendly in the world of refrigerators had not yet been invented. However, in terms of the reliability of thermoacoustic refrigerators is greatly inferior to the good old «bad» refrigerators.

2. Welding

Ultrasonic waves were used for plastics welding in 1960. It works by compressing two thermoplastic materials together on top of the support. Ultrasonic waves then make their molecules move actively, resulting in a very high temperature friction. In the end, two pieces of plastic to melt very evenly and beautifully.

Like many other discoveries, it was made quite by accident. Robert Soloff (well, you understand, in what country are obliged his ancestors) has been working with ultrasonic equipment. Well, as usual, sloppy Robert touched the tip of the dispenser Scotch that stood on the table. As a result, the two halves are stuck together. After the realization that it is evenly heated plastic can bend like a joint, on all sides, Soloff has patented the discovery and began to enjoy his triumph, since ultrasonic welding has found wide application in many industries, from toys to cars. Recently, the US Navy began to experiment with using this technology to make «welds» for their uniforms. If the clothing material is a thermoplastic, such as nylon, ultrasonic welding can be used for joints that are stronger and better insulated than traditional. But there is one problem: made the old fashioned way seams more reliable and cheaper than thermoplastic. So what about the widespread introduction of technology can not even think.

3. Credit cards and banks

Here, they say, there would be no happiness, Yes the misfortune has helped. Researchers have found a way to transfer data from computer to computer using just the sound. However, there is one BUT: it is a very efficient way to transmit viruses. Security consultant Dragos Ruiu came to this idea, noticing something strange about his MacBook Air: after installing OS X computer updated its boot firmware spontaneously. It turned out, it was a very powerful virus that can lead to the deletion of the data and make changes at will. Even after uninstalling, reinstalling and reconfiguring the entire system insidious virus remained seated in the computer. The most plausible theory of the immortality of the virus was said that he lived in the BIOS. Another unlikely theory was that the virus penetrated using high frequency transmission, and when data is transmitted between the speakers and microphones.

It seemed nonsense to until a German Institute has not found a way to reproduce this effect. Based on software developed for underwater communications were made a prototype of malware that was sent through the non-network laptops using only your speakers. In tests laptops can «talk». Well, if you link all of the infected device network, like Wi-Fi, the range can easily expand. The good news is that the acoustic transfer is extremely slow, reaching only 20 bits per second. Although this is not enough to transfer large packages, but enough to send passwords, credit card numbers and encryption keys. However, viruses are not asleep, and there is no guarantee that this method will fall under the blows of the cruel viruses.

4. Scalpel

Physicians have long used acoustic waves for medical procedures such as ultrasound and fragmentation of kidney stones, but researchers at the University of Michigan did an acoustic scalpel, and so accurate that they can be separated one cell. The modern technology of focused ultrasound can only create a beam that has a focal spot approximately a few millimeters, but the new instrument has a accuracy of 75 x 400 micrometers. For comparison you get in the tutorial and find out what the difference between millimeters and microns.

Theoretically, the technology has been known since the end of 1800 years, and just did not have the technical ability to create a «sound». It turned out only recently, with the help of a lens coated with carbon nanotubes and material called polydimethylsiloxane to convert the light into sound waves of high pressure. Tightly focused acoustic waves create shock waves and microbubbles that exert pressure on the microscopic level. But we really do not care about all these terms, we are important to use. And she kind of is, because the scalpel was already tested and was able to detach a single ovarian cancer cell and drilling a hole the size of 150 micrometers into an artificial kidney stone. The developers hope that it can be later used for administration of drugs or to eliminate small cancer tumors or plaques. It is possible that the scalpel can perform these operations painlessly, since the beam is so precise that it can avoid contact with nerve cells. So we will watch with bated breath and hope that this way as soon as possible will introduce dentists, and going to them will not be so painful.

5. Disney microphone

Researchers from Disney have created a device that turns the human body into the microphone. This device, called «Ishin-Den-Shin», which translated c language «land of the Rising Sun» means «communication through unspoken mutual understanding» that allows a person to silently transmit a recorded message by simply touching the ear of another person.

The device they made, includes a microphone connected to the computer. When someone speaks into the microphone, the computer saves the sound as a double record, which is then transformed into an inaudible signal. This signal is transmitted via wires connected to the microphone. The signal is transmitted from the microphone to the body of any person who holds it. This creates a modulated electrostatic field, which causes tiny fluctuations, if the person touches something. The vibration can be heard if to touch the ear of another person. It can even be transmitted through the chain from person to person, if the group is in physical contact. And this way of communication is very common.

6. Reading voice

Researchers from mit, Microsoft and Adobe have developed an algorithm that can read passive sounds of inanimate objects in the video. Their algorithm analyzes imperceptible vibrations, acoustic waves create on the surfaces and make them audible. In one experiment with a pack of chips was recovered expressive speech recorded at a distance of 4.5 meters through the soundproof glass.

For best results, the algorithm, the number of frames per second the video stream should be less than the frequency of the signal, which requires high-speed cameras. So there need not some soapbox, and at least a digital camera, in order to determine the number of people talking in the room, their gender and possibly even their personality. New technology has obvious applications for forensic examination, law enforcement and spy war. With it, all you need to do is to send high-speed digital camera in the window to record what is happening inside. In short, James bond and Inspector Gadget would approve of.

7. Disguise

Researchers have created a device that can hide objects from sound. It looks like a bizarre pyramid, with many holes, however, this form changes the trajectory of the sound waves so that it matches how it would look if they were reflected from a flat surface. If you put acoustic masking of the object on a flat surface, it will be beyond the reach of the sound no matter what angle you look at him.

This technology is able to combine objects in places where acoustics has great value. For example, concert halls. In case you need to some spectacular shows. But there is one thing: subsidies for the study were obtained from the American military, therefore, most likely, it will be used in a purely democratic order: the struggle against injustice and lack of all oil greedy American legs. The device does not retain sound inside, but it can hide objects from detection systems that are based on sound, such as sonar. Since underwater sound is in the same way as in air, sound masking may end up to help submarines to remain invisible to detection systems.

8. Charging for phone

Nanotechnologies are used to collect energy from various sources to generate electricity. One of their purposes is to create devices that do not need to be recharged. In particular, the company «Nokia» has even patented a device that receives energy from the movement of the user.

In essence, sound is a potential source of energy. Researchers are experimenting with methods by which you can charge your mobile phone while talking on it. In 2011, researchers from Seoul used nano-rods of zinc oxide sandwiched between two electrodes to generate electricity sound waves. The technology can generate 50 millivolts due to the volume of noisy traffic. It’s not enough to charge most electrical devices, however in the past year, colleagues from London took up the idea and were able to create a device that can produce 5 volts, which is enough to charge the phone.

Of course, this is great news for Android lovers. Who-who, «androids» know a lot about how to discharge at the most inopportune moment.