Tag Archives: Yoel Fink

Sound-suppressing silk

I keep telling a friend that noise will be the ‘new smoking’; i.e., there will be more rules and people will demand enforcement. She doesn’t agree, vociferously so. With the mounting research into the effects that noise has on health and on longevity, it doesn’t matter if I win the ‘argument’, I’m just happy to see research dedicated to mitigating noise levels. From a May 7, 2024 news item on ScienceDaily,

We are living in a very noisy world. From the hum of traffic outside your window to the next-door neighbor’s blaring TV to sounds from a co-worker’s cubicle, unwanted noise remains a resounding problem. [nice bit of wordplay]

Caption: The fabric can suppress sound by generating sound waves that interfere with an unwanted noise to cancel it out (as seen in figure C) or by being held still to suppress vibrations that are key to the transmission of sound (as seen in figure D). Credit: Courtesy of Yoel Fink and Grace (Noel) Yang and Massachusetts Institute of Technology (MIT)

A May 7, 2024 Massachusetts Institute of Technology (MIT) news release (also on EurekAlert), which originated the news item, describes how a surprising material, silk, can be used for suppressing sound, Note: Links have been removed,

To cut through the din, an interdisciplinary collaboration of researchers from MIT and elsewhere developed a sound-suppressing silk fabric that could be used to create quiet spaces. 

The fabric, which is barely thicker than a human hair, contains a special fiber that vibrates when a voltage is applied to it. The researchers leveraged those vibrations to suppress sound in two different ways.

In one, the vibrating fabric generates sound waves that interfere with an unwanted noise to cancel it out, similar to noise-canceling headphones, which work well in a small space like your ears but do not work in large enclosures like rooms or planes. 

In the other, more surprising technique, the fabric is held still to suppress vibrations that are key to the transmission of sound. This prevents noise from being transmitted through the fabric and quiets the volume beyond. This second approach allows for noise reduction in much larger spaces like rooms or cars.

By using common materials like silk, canvas, and muslin, the researchers created noise-suppressing fabrics which would be practical to implement in real-world spaces. For instance, one could use such a fabric to make dividers in open workspaces or thin fabric walls that prevent sound from getting through. 

“Noise is a lot easier to create than quiet. In fact, to keep noise out we dedicate a lot of space to thick walls. [First author] Grace’s work provides a new mechanism for creating quiet spaces with a thin sheet of fabric,” says Yoel Fink, a professor in the departments of Materials Science and Engineering and Electrical Engineering and Computer Science, a Research Laboratory of Electronics principal investigator, and senior author of a paper on the fabric.

The study’s lead author is Grace (Noel) Yang SM ’21, PhD ’24. Co-authors include MIT graduate students Taigyu Joo, Hyunhee Lee, Henry Cheung, and Yongyi Zhao; Zachary Smith, the Robert N. Noyce Career Development Professor of Chemical Engineering at MIT; graduate student Guanchun Rui and professor Lei Zhu of Case Western [Reserve] University; graduate student Jinuan Lin and Assistant Professor Chu Ma of the University of Wisconsin at Madison; and Latika Balachander, a graduate student at the Rhode Island School of Design. The an open-access paper about the research appeared recently in Advanced Materials.

Silky silence

The sound-suppressing silk builds off the group’s prior work to create fabric microphones.

In that research, they sewed a single strand of piezoelectric fiber into fabric. Piezoelectric materials produce an electrical signal when squeezed or bent. When a nearby noise causes the fabric to vibrate, the piezoelectric fiber converts those vibrations into an electrical signal, which can capture the sound. 

In the new work, the researchers flipped that idea to create a fabric loudspeaker that can be used to cancel out soundwaves. 

“While we can use fabric to create sound, there is already so much noise in our world. We thought creating silence could be even more valuable,” Yang says.

Applying an electrical signal to the piezoelectric fiber causes it to vibrate, which generates sound. The researchers demonstrated this by playing Bach’s “Air” using a 130-micrometer sheet of silk mounted on a circular frame.

To enable direct sound suppression, the researchers use a silk fabric loudspeaker to emit sound waves that destructively interfere with unwanted sound waves. They control the vibrations of the piezoelectric fiber so that sound waves emitted by the fabric are opposite of unwanted sound waves that strike the fabric, which can cancel out the noise.

However, this technique is only effective over a small area. So, the researchers built off this idea to develop a technique that uses fabric vibrations to suppress sound in much larger areas, like a bedroom.

Let’s say your next-door neighbors are playing foosball in the middle of the night. You hear noise in your bedroom because the sound in their apartment causes your shared wall to vibrate, which forms sound waves on your side.

To suppress that sound, the researchers could place the silk fabric onto your side of the shared wall, controlling the vibrations in the fiber to force the fabric to remain still. This vibration-mediated suppression prevents sound from being transmitted through the fabric.

“If we can control those vibrations and stop them from happening, we can stop the noise that is generated, as well,” Yang says.

A mirror for sound

Surprisingly, the researchers found that holding the fabric still causes sound to be reflected by the fabric, resulting in a thin piece of silk that reflects sound like a mirror does with light. 

Their experiments also revealed that both the mechanical properties of a fabric and the size of its pores affect the efficiency of sound generation. While silk and muslin have similar mechanical properties, the smaller pore sizes of silk make it a better fabric loudspeaker. 

But the effective pore size also depends on the frequency of sound waves. If the frequency is low enough, even a fabric with relatively large pores could function effectively, Yang says.

When they tested the silk fabric in direct suppression mode, the researchers found that it could significantly reduce the volume of sounds up to 65 decibels (about as loud as enthusiastic human conversation). In vibration-mediated suppression mode, the fabric could reduce sound transmission up to 75 percent.

These results were only possible due to a robust group of collaborators, Fink says. Graduate students at the Rhode Island School of Design helped the researchers understand the details of constructing fabrics; scientists at the University of Wisconsin at Madison conducted simulations; researchers at Case Western Reserve University characterized materials; and chemical engineers in the Smith Group at MIT used their expertise in gas membrane separation to measure airflow through the fabric.

Moving forward, the researchers want to explore the use of their fabric to block sound of multiple frequencies. This would likely require complex signal processing and additional electronics. 

In addition, they want to further study the architecture of the fabric to see how changing things like the number of piezoelectric fibers, the direction in which they are sewn, or the applied voltages could improve performance.

“There are a lot of knobs we can turn to make this sound-suppressing fabric really effective. We want to get people thinking about controlling structural vibrations to suppress sound. This is just the beginning,” says Yang.

This work is funded, in part, by the National Science Foundation (NSF), the Army Research Office (ARO), the Defense Threat Reduction Agency (DTRA), and the Wisconsin Alumni Research Foundation.

Here’s a link to and a citation for the paper,

Single Layer Silk and Cotton Woven Fabrics for Acoustic Emission and Active Sound Suppression by Grace H. Yang, Jinuan Lin, Henry Cheung, Guanchun Rui, Yongyi Zhao, Latika Balachander, Taigyu Joo, Hyunhee Lee, Zachary P. Smith, Lei Zhu, Chu Ma, Yoel Fink. Advanced Materials DOI: https://doi.org/10.1002/adma.202313328 First published: 01 April 2024

This paper is open access.

“Breaking Me Softly” at the nanoscale

“Breaking Me Softly” sounds like a song title but in this case the phrase as been coined to describe a new technique for controlling materials at the nanoscale according to a June 6, 2016 news item on ScienceDaily,

A finding by a University of Central Florida researcher that unlocks a means of controlling materials at the nanoscale and opens the door to a new generation of manufacturing is featured online in the journal Nature.

Using a pair of pliers in each hand and gradually pulling taut a piece of glass fiber coated in plastic, associate professor Ayman Abouraddy found that something unexpected and never before documented occurred — the inner fiber fragmented in an orderly fashion.

“What we expected to see happen is NOT what happened,” he said. “While we thought the core material would snap into two large pieces, instead it broke into many equal-sized pieces.”

He referred to the technique in the Nature article title as “Breaking Me Softly.”

A June 6, 2016 University of Central Florida (UCF) news release (also on EurekAlert) by Barbara Abney, which originated the news item, expands on the theme,

The process of pulling fibers to force the realignment of the molecules that hold them together, known as cold drawing, has been the standard for mass production of flexible fibers like plastic and nylon for most of the last century.

Abouraddy and his team have shown that the process may also be applicable to multi-layered materials, a finding that could lead to the manufacturing of a new generation of materials with futuristic attributes.

“Advanced fibers are going to be pursuing the limits of anything a single material can endure today,” Abouraddy said.

For example, packaging together materials with optical and mechanical properties along with sensors that could monitor such vital sign as blood pressure and heart rate would make it possible to make clothing capable of transmitting vital data to a doctor’s office via the Internet.

The ability to control breakage in a material is critical to developing computerized processes for potential manufacturing, said Yuanli Bai, a fracture mechanics specialist in UCF’s College of Engineering and Computer Science.

Abouraddy contacted Bai, who is a co-author on the paper, about three years ago and asked him to analyze the test results on a wide variety of materials, including silicon, silk, gold and even ice.

He also contacted Robert S. Hoy, a University of South Florida physicist who specializes in the properties of materials like glass and plastic, for a better understanding of what he found.

Hoy said he had never seen the phenomena Abouraddy was describing, but that it made great sense in retrospect.

The research takes what has traditionally been a problem in materials manufacturing and turned it into an asset, Hoy said.

“Dr. Abouraddy has found a new application of necking” –  a process that occurs when cold drawing causes non-uniform strain in a material, Hoy said.  “Usually you try to prevent necking, but he exploited it to do something potentially groundbreaking.”

The necking phenomenon was discovered decades ago at DuPont and ushered in the age of textiles and garments made of synthetic fibers.

Abouraddy said that cold-drawing is what makes synthetic fibers like nylon and polyester useful. While those fibers are initially brittle, once cold-drawn, the fibers toughen up and become useful in everyday commodities. This discovery at DuPont at the end of the 1920s ushered in the age of textiles and garments made of synthetic fibers.

Only recently have fibers made of multiple materials become possible, he said.  That research will be the centerpiece of a $317 Million U.S. Department of Defense program focused on smart fibers that Abouraddy and UCF will assist with.   The Revolutionary Fibers and Textiles Manufacturing Innovation Institute (RFT-MII), led by the Massachusetts Institute of Technology, will incorporate research findings published in the Nature paper, Abouraddy said.

The implications for manufacturing of the smart materials of the future are vast.

By controlling the mechanical force used to pull the fiber and therefore controlling the breakage patterns, materials can be developed with customized properties allowing them to interact with each other and eternal forces such as the sun (for harvesting energy) and the internet in customizable ways.

A co-author on the paper, Ali P. Gordon, an associate professor in the Department of Mechanical & Aerospace Engineering and director of UCF’s Mechanics of Materials Research Group said that the finding is significant because it shows that by carefully controlling the loading condition imparted to the fiber, materials can be developed with tailored performance attributes.

“Processing-structure-property relationships need to be strategically characterized for complex material systems. By combining experiments, microscopy, and computational mechanics, the physical mechanisms of the fragmentation process were more deeply understood,” Gordon said.

Abouraddy teamed up with seven UCF scientists from the College of Optics & Photonics and the College of Engineering & Computer Science (CECS) to write the paper.   Additional authors include one researcher each from the Massachusetts Institute of Technology, Nanyang Technological University in Singapore and the University of South Florida.

Here’s a link to and a citation for the paper,

Controlled fragmentation of multimaterial fibres and films via polymer cold-drawing by Soroush Shabahang, Guangming Tao, Joshua J. Kaufman, Yangyang Qiao, Lei Wei, Thomas Bouchenot, Ali P. Gordon, Yoel Fink, Yuanli Bai, Robert S. Hoy & Ayman F. Abouraddy. Nature (2016) doi:10.1038/nature17980 Published online  06 June 2016

This paper is behind a paywall.

Noisy new world with clothing that sings and records and varnishes that ring alarms

They’re called functional fibres and a team at MIT (Massachusetts Institute of Technology) has taken another step forward in achieving fibres that can produce and detect sound. From the news item on physorg.com,

For centuries, “man-made fibers” meant the raw stuff of clothes and ropes; in the information age, it’s come to mean the filaments of glass that carry data in communications networks. But to Yoel Fink, an Associate professor of Materials Science and principal investigator at MIT’s Research Lab of Electronics, the threads used in textiles and even optical fibers are much too passive. For the past decade, his lab has been working to develop fibers with ever more sophisticated properties, to enable fabrics that can interact with their environment.

… Applications could include clothes that are themselves sensitive microphones, for capturing speech or monitoring bodily functions, and tiny filaments that could measure blood flow in capillaries or pressure in the brain. The paper, whose authors also include Shunji Egusa, a former postdoc in Fink’s lab, and current lab members Noémie Chocat and Zheng Wang, appeared on Nature Materials‘ website on July 11, and the work it describes was supported by MIT’s Institute for Soldier Nanotechnologies, the National Science Foundation and the U.S. Defense Department’s Defense Advanced Research Projects Agency. [emphases mine]

Interesting to note all of the military interest.

The heart of the new acoustic fibers is a plastic commonly used in microphones. By playing with the plastic’s fluorine content, the researchers were able to ensure that its molecules remain lopsided — with fluorine atoms lined up on one side and hydrogen atoms on the other — even during heating and drawing. The asymmetry of the molecules is what makes the plastic “piezoelectric,” meaning that it changes shape when an electric field is applied to it.

I’m not sure how this fits with Professor Zhong Lin Wang’s work in the field of piezotronics  (July 12, 2010 posting) and I’m not looking at the technical aspect so much as the social impact of clothing made of fibres that can harvest biomechanical energy and/or record sound and/or produce sound. In other words, what’s the social impact? In all the talk about developing new products and getting them to market,  I haven’t found that much discussion about whether people are going to adopt products that are constantly monitoring their health or given to making a sound for one reason or another. When you add in the other work on such things as varnishes that emit sounds as they cool or heat (Feb. 3, 2010, 2nd excerpt, last paragraph), you have to come to the conclusion that at the very least it’s going to be a very noisy world in the future. Questions that come to mind include: will these fibres that can monitor our health or record sounds or the varnishes that sound alarms have an off button? What happens if they malfunction?