Tag Archives: sound

Evolution of literature as seen by a classicist, a biologist and a computer scientist

Studying intertextuality shows how books are related in various ways and are reorganized and recombined over time. Image courtesy of Elena Poiata.

I find the image more instructive when I read it from the bottom up. For those who prefer to prefer to read from the top down, there’s this April 5, 2017 University of Texas at Austin news release (also on EurekAlert),

A classicist, biologist and computer scientist all walk into a room — what comes next isn’t the punchline but a new method to analyze relationships among ancient Latin and Greek texts, developed in part by researchers from The University of Texas at Austin.

Their work, referred to as quantitative criticism, is highlighted in a study published in the Proceedings of the National Academy of Sciences. The paper identifies subtle literary patterns in order to map relationships between texts and more broadly to trace the cultural evolution of literature.

“As scholars of the humanities well know, literature is a system within which texts bear a multitude of relationships to one another. Understanding what is distinctive about one text entails knowing how it fits within that system,” said Pramit Chaudhuri, associate professor in the Department of Classics at UT Austin. “Our work seeks to harness the power of quantification and computation to describe those relationships at macro and micro levels not easily achieved by conventional reading alone.”

In the study, the researchers create literary profiles based on stylometric features, such as word usage, punctuation and sentence structure, and use techniques from machine learning to understand these complex datasets. Taking a computational approach enables the discovery of small but important characteristics that distinguish one work from another — a process that could require years using manual counting methods.

“One aspect of the technical novelty of our work lies in the unusual types of literary features studied,” Chaudhuri said. “Much computational text analysis focuses on words, but there are many other important hallmarks of style, such as sound, rhythm and syntax.”

Another component of their work builds on Matthew Jockers’ literary “macroanalysis,” which uses machine learning to identify stylistic signatures of particular genres within a large body of English literature. Implementing related approaches, Chaudhuri and his colleagues have begun to trace the evolution of Latin prose style, providing new, quantitative evidence for the sweeping impact of writers such as Caesar and Livy on the subsequent development of Roman prose literature.

“There is a growing appreciation that culture evolves and that language can be studied as a cultural artifact, but there has been less research focused specifically on the cultural evolution of literature,” said the study’s lead author Joseph Dexter, a Ph.D. candidate in systems biology at Harvard University. “Working in the area of classics offers two advantages: the literary tradition is a long and influential one well served by digital resources, and classical scholarship maintains a strong interest in close linguistic study of literature.”

Unusually for a publication in a science journal, the paper contains several examples of the types of more speculative literary reading enabled by the quantitative methods introduced. The authors discuss the poetic use of rhyming sounds for emphasis and of particular vocabulary to evoke mood, among other literary features.

“Computation has long been employed for attribution and dating of literary works, problems that are unambiguous in scope and invite binary or numerical answers,” Dexter said. “The recent explosion of interest in the digital humanities, however, has led to the key insight that similar computational methods can be repurposed to address questions of literary significance and style, which are often more ambiguous and open ended. For our group, this humanist work of criticism is just as important as quantitative methods and data.”

The paper is the work of the Quantitative Criticism Lab (www.qcrit.org), co-directed by Chaudhuri and Dexter in collaboration with researchers from several other institutions. It is funded in part by a 2016 National Endowment for the Humanities grant and the Andrew W. Mellon Foundation New Directions Fellowship, awarded in 2016 to Chaudhuri to further his education in statistics and biology. Chaudhuri was one of 12 scholars selected for the award, which provides humanities researchers the opportunity to train outside of their own area of special interest with a larger goal of bridging the humanities and social sciences.

Here’s another link to the paper along with a citation,

Quantitative criticism of literary relationships by Joseph P. Dexter, Theodore Katz, Nilesh Tripuraneni, Tathagata Dasgupta, Ajay Kannan, James A. Brofos, Jorge A. Bonilla Lopez, Lea A. Schroeder, Adriana Casarez, Maxim Rabinovich, Ayelet Haimson Lushkov, and Pramit Chaudhuri. PNAS Published online before print April 3, 2017, doi: 10.1073/pnas.1611910114

This paper appears to be open access.

Curiosity Collider (Vancouver, Canada) presents Neural Constellations: Exploring Connectivity

I think of Curiosity Collider as an informal art/science  presenter but I gather the organizers’ ambitions are more grand. From the Curiosity Collider’s About Us page,

Curiosity Collider provides an inclusive community [emphasis mine] hub for curious innovators from any discipline. Our non-profit foundation, based in Vancouver, Canada, fosters participatory partnerships between science & technology, art & culture, business communities, and educational foundations to inspire new ways to experience science. The Collider’s growing community supports and promotes the daily relevance of science with our events and projects. Curiosity Collider is a catalyst for collaborations that seed and grow engaging science communication projects.

Be inspired by the curiosity of others. Our Curiosity Collider events cross disciplinary lines to promote creative inspiration. Meet scientists, visual and performing artists, culinary perfectionists, passionate educators, and entrepreneurs who share a curiosity for science.

Help us create curiosity for science. Spark curiosity in others with your own ideas and projects. Get in touch with us and use our curiosity events to showcase how your work creates innovative new ways to experience science.

I wish they hadn’t described themselves as an “inclusive community.” This often means exactly the opposite.

Take for example the website. The background is in black, the heads are white, and the text is grey. This is a website for people under the age of 40. If you want to be inclusive, you make your website legible for everyone.

That said, there’s an upcoming Curiosity Collider event which looks promising (from a July 20, 2016 email notice),

Neural Constellations: Exploring Connectivity

An Evening of Art, Science and Performance under the Dome

“We are made of star stuff,” Carl Sagan once said. From constellations to our nervous system, from stars to our neurons. We’re colliding neuroscience and astronomy with performance art, sound, dance, and animation for one amazing evening under the planetarium dome. Together, let’s explore similar patterns at the macro (astronomy) and micro (neurobiology) scale by taking a tour through both outer and inner space.

This show is curated by Curiosity Collider’s Creative Director Char Hoyt, along with Special Guest Curator Naila Kuhlmann, and developed in collaboration with the MacMillan Space Centre. There will also be an Art-Science silent auction to raise funding for future Curiosity Collider activities.

Participating performers include:

The July 20, 2016 notice also provides information about date, time, location, and cost,

7:30pm on Thursday, August 18th 2016. Join us for drinks and snacks when doors open at 6:30pm.

H. R. MacMillan Space Centre (1100 Chestnut Street, Vancouver, BC)

$20.00 sliding scale. Proceeds will be used to cover the cost of running this event, and to fund future Curiosity Collider events. Curiosity Collider is a registered BC non-profit organization. Purchase tickets on our Eventbrite page.

Head to the Facebook event page: Let us know you are coming and share this event with others! We will also share event updates and performer profiles on the Facebook page.

There is a pretty poster,


[downloaded from http://www.curiositycollider.org/events/]


Café Scientifique (Vancouver, Canada) and noise on Oct. 27, 2015

On Tuesday, October 27, 2015  Café Scientifique, in the back room of The Railway Club (2nd floor of 579 Dunsmuir St. [at Seymour St.]), will be hosting a talk on the history of noise (from the Oct. 13, 2015 announcement),

Our speaker for the evening will be Dr. Shawn Bullock.  The title of his talk is:

The History of Noise: Perspectives from Physics and Engineering

The word “noise” is often synonymous with “nuisance,” which implies something to be avoided as much as possible. We label blaring sirens, the space between stations on the radio dial and the din of a busy street as “noise.” Is noise simply a sound we don’t like? We will consider the evolution of how scientists and engineers have thought about noise, beginning in the 19th-century and continuing to the present day. We will explore the idea of noise both as a social construction and as a technological necessity. We’ll also touch on critical developments in the study of sound, the history of physics and engineering, and the development of communications technology.

This description is almost identical to the description Bullock gave for a November 2014 talk he titled: Snap, Crackle, Pop!: A Short History of Noise which he summarizes this way after delivering the talk,

I used ideas from the history of physics, the history of music, the discipline of sound studies, and the history of electrical engineering to make the point that understanding “noise” is essential to understanding advancements in physics and engineering in the last century. We began with a discussion of 19th-century attitudes toward noise (and its association with “progress” and industry) before moving on to examine the early history of recorded sound and music, early attempts to measure noise, and the noise abatement movement. I concluded with a brief overview of my recent work on the role of noise in the development of the modem during the early Cold War.

You can find out more about Dr. Bullock who is an assistant professor of science education at Simon Fraser University here at his website.

On the subject of noise, although not directly related to Bullock’s work, there’s some research suggesting that noise may be having a serious impact on marine life. From an Oct. 8, 2015 Elsevier press release on EurekAlert,

Quiet areas should be sectioned off in the oceans to give us a better picture of the impact human generated noise is having on marine animals, according to a new study published in Marine Pollution Bulletin. By assigning zones through which ships cannot travel, researchers will be able to compare the behavior of animals in these quiet zones to those living in noisier areas, helping decide the best way to protect marine life from harmful noise.

The authors of the study, from the University of St Andrews, UK, the Oceans Initiative, Cornell University, USA, and Curtin University, Australia, say focusing on protecting areas that are still quiet will give researchers a better insight into the true impact we are having on the oceans.

Almost all marine organisms, including mammals like whales and dolphins, fish and even invertebrates, use sound to find food, avoid predators, choose mates and navigate. Chronic noise from human activities such as shipping can have a big impact on these animals, since it interferes with their acoustic signaling – increased background noise can mean animals are unable to hear important signals, and they tend to swim away from sources of noise, disrupting their normal behavior.

The number of ships in the oceans has increased fourfold since 1992, increasing marine noise dramatically. Ships are also getting bigger, and therefore noisier: in 2000 the biggest cargo ships could carry 8,000 containers; today’s biggest carry 18,000.

“Marine animals, especially whales, depend on a naturally quiet ocean for survival, but humans are polluting major portions of the ocean with noise,” said Dr. Christopher Clark from the Bioacoustics Research Program, Cornell University. “We must make every effort to protect quiet ocean regions now, before they grow too noisy from the din of our activities.”

For the new study, lead author Dr. Rob Williams and the team mapped out areas of high and low noise pollution in the oceans around Canada. Using shipping route and speed data from Environment Canada, the researchers put together a model of noise based on ships’ location, size and speed, calculating the cumulative sound they produce over the course of a year. They used the maps to predict how noisy they thought a particular area ought to be.

To test their predictions, in partnership with Cornell University, they deployed 12 autonomous hydrophones – devices that can measure noise in water – and found a correlation in terms of how the areas ranked from quietest to noisiest. The quiet areas are potential noise conservation zones.

“We tend to focus on problems in conservation biology. This was a fun study to work on, because we looked for opportunities to protect species by working with existing patterns in noise and animal distribution, and found that British Colombia offers many important habitat for whales that are still quiet,” said Dr. Rob Williams, lead author of the study. “If we think of quiet, wild oceans as a natural resource, we are lucky that Canada is blessed with globally rare pockets of acoustic wilderness. It makes sense to talk about protecting acoustic sanctuaries before we lose them.”

Although it is clear that noise has an impact on marine organisms, the exact effect is still not well understood. By changing their acoustic environment, we could be inadvertently choosing winners and losers in terms of survival; researchers are still at an early stage of predicting who will win or lose under different circumstances. The quiet areas the team identified could serve as experimental control sites for research like the International Quiet Ocean Experiment to see what effects ocean noise is having on marine life.

“Sound is perceived differently by different species, and some are more affected by noise than others,” said Christine Erbe, co-author of the study and Director of the Marine Science Center, Curtin University, Australia.

So far, the researchers have focused on marine mammals – whales, dolphins, porpoises, seals and sea lions. With a Pew Fellowship in Marine Conservation, Dr. Williams now plans to look at the effects of noise on fish, which are less well understood. By starting to quantify that and let people know what the likely economic effect on fisheries or on fish that are culturally important, Dr. Williams hopes to get the attention of the people who make decisions that affect ocean noise.

“When protecting highly mobile and migratory species that are poorly studied, it may make sense to focus on threats rather than the animals themselves. Shipping patterns decided by humans are often more predictable than the movements of whales and dolphins,” said Erin Ashe, co-author of the study and co-founder of the Oceans Initiative from the University of St Andrews.

Keeping areas of the ocean quiet is easier than reducing noise in already busy zones, say the authors of the study. However, if future research that stems from noise protected zones indicates that overall marine noise should be reduced, there are several possible approaches to reducing noise. The first is speed reduction: the faster a ship goes, the noisier it gets, so slowing down would reduce overall noise. The noisiest ships could also be targeted for replacement: by reducing the noise produced by the noisiest 10% of ships in use today, overall marine noise could be reduced by more than half. The third, more long-term, option would be to build quieter ships from the outset.

I can’t help wondering why Canadian scientists aren’t involved in this research taking place off our shores. Regardless, here’s a link to and a citation for the paper,

Quiet(er) marine protected areas by Rob Williams, Christine Erbe, Erin Ashe, & Christopher W. Clark. Marine Pollution Bulletin Available online 16 September 2015 In Press, Corrected Proof doi:10.1016/j.marpolbul.2015.09.012

This is an open access paper.

“Ears like a bat” could come true for humans?

That old saying which describes people with exceptional hearing as having “ears like a bat” may come true if University of California at Berkeley (UC Berkeley) researchers have their way. From a July 7, 2015 news item on Nanowerk,

University of California, Berkeley, physicists have used graphene to build lightweight ultrasonic loudspeakers and microphones, enabling people to mimic bats or dolphins’ ability to use sound to communicate and gauge the distance and speed of objects around them.

A July 6, 2015 UC Berkeley news release by Robert Sanders (also on EurekAlert), which originated the news item, describes the problem addressed by the research and the new approach taken,

More practically, the wireless ultrasound devices complement standard radio transmission using electromagnetic waves in areas where radio is impractical, such as underwater, but with far more fidelity than current ultrasound or sonar devices. They can also be used to communicate through objects, such as steel, that electromagnetic waves can’t penetrate.

“Sea mammals and bats use high-frequency sound for echolocation and communication, but humans just haven’t fully exploited that before, in my opinion, because the technology has not been there,” said UC Berkeley physicist Alex Zettl. “Until now, we have not had good wideband ultrasound transmitters or receivers. These new devices are a technology opportunity.”

Speakers and microphones both use diaphragms, typically made of paper or plastic, that vibrate to produce or detect sound, respectively. The diaphragms in the new devices are graphene sheets a mere one atom thick that have the right combination of stiffness, strength and light weight to respond to frequencies ranging from subsonic (below 20 hertz) to ultrasonic (above 20 kilohertz). Humans can hear from 20 hertz up to 20,000 hertz, whereas bats hear only in the kilohertz range, from 9 to 200 kilohertz. The grapheme loudspeakers and microphones operate from well below 20 hertz to over 500 kilohertz.

Graphene consists of carbon atoms laid out in a hexagonal, chicken-wire arrangement, which creates a tough, lightweight sheet with unique electronic properties that have excited the physics world for the past 20 or more years.

“There’s a lot of talk about using graphene in electronics and small nanoscale devices, but they’re all a ways away,” said Zettl, who is a senior scientist at Lawrence Berkeley National Laboratory and a member of the Kavli Energy NanoSciences Institute, operated jointly by UC Berkeley and Berkeley Lab. “The microphone and loudspeaker are some of the closest devices to commercial viability, because we’ve worked out how to make the graphene and mount it, and it’s easy to scale up.”

Zettl, UC Berkeley postdoctoral fellow Qin Zhou and colleagues describe their graphene microphone and ultrasonic radio in a paper appearing online this week in the Proceedings of the National Academy of Sciences.

Radios and rangefinders

Two years ago, Zhou built loudspeakers using a sheet of graphene for the diaphragm, and since then has been developing the electronic circuitry to build a microphone with a similar graphene diaphragm.

One big advantage of graphene is that the atom-thick sheet is so lightweight that it responds well to the different frequencies of an electronic pulse, unlike today’s piezoelectric microphones and speakers. This comes in handy when using ultrasonic transmitters and receivers to transmit large amounts of information through many different frequency channels simultaneously, or to measure distance, as in sonar applications.

“Because our membrane is so light, it has an extremely wide frequency response and is able to generate sharp pulses and measure distance much more accurately than traditional methods,” Zhou said.

Graphene membranes are also more efficient, converting over 99 percent of the energy driving the device into sound, whereas today’s conventional loudspeakers and headphones convert only 8 percent into sound. Zettl anticipates that in the future, communications devices like cellphones will utilize not only electromagnetic waves – radio – but also acoustic or ultrasonic sound, which can be highly directional and long-range.

“Graphene is a magical material; it hits all the sweet spots for a communications device,” he said.

You never know who can give you a new idea for your research, from the news release,

When Zhou told his wife, Jinglin Zheng [also a physicist], about the ultrasound microphone, she suggested he try to capture the sound of bats chirping at frequencies too high for humans to hear. So they hauled the microphone to a park in Livermore and turned it on. When they slowed down the recording to one-tenth normal speed, converting the high frequencies to an audio range humans can hear, they were amazed at the quality and fidelity of the bat vocalizations.

“This is lightweight enough to mount on a bat and record what the bat can hear,” Zhou said.

Bat expert Michael Yartsev, a newly hired UC Berkeley assistant professor of bioengineering and member of the Helen Wills Neuroscience Institute, said, “These new microphones will be incredibly valuable for studying auditory signals at high frequencies, such as the ones used by bats. The use of graphene allows the authors to obtain very flat frequency responses in a wide range of frequencies, including ultrasound, and will permit a detailed study of the auditory pulses that are used by bats.”

Zettl noted that audiophiles would also appreciate the graphene loudspeakers and headphones, which have a flat response across the entire audible frequency range.

“A number of years ago, this device would have been darn near impossible to build because of the difficulty of making free-standing graphene sheets,” Zettl said. “But over the past decade the graphene community has come together to develop techniques to grow, transport and mount graphene, so building a device like this is now very straightforward; the design is simple.”

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

Graphene electrostatic microphone and ultrasonic radio by Qin Zhou, Jinglin Zheng, Seita Onishi, M. F. Crommie, Alex K. Zettl. Proceedings of the National Academy of Sciences, 2015; 201505800 DOI: 10.1073/pnas.1505800112

This paper is behind a paywall.

Twinkle, Twinkle Little Star (song) could lead to better data storage

A March 16, 2015 news item on Nanowerk features research from the University of Illinois and the song ‘Twinkle, Twinkle Little Star’,

Researchers from the University of Illinois at Urbana-Champaign have demonstrated the first-ever recording of optically encoded audio onto a non-magnetic plasmonic nanostructure, opening the door to multiple uses in informational processing and archival storage.

“The chip’s dimensions are roughly equivalent to the thickness of human hair,” explained Kimani Toussaint, an associate professor of mechanical science and engineering, who led the research.

Specifically, the photographic film property exhibited by an array of novel gold, pillar-supported bowtie nanoantennas (pBNAs)–previously discovered by Toussaint’s group–was exploited to store sound and audio files. Compared with the conventional magnetic film for analog data storage, the storage capacity of pBNAs is around 5,600 times larger, indicating a vast array of potential storage uses.

The researchers have provide a visual image illustrating their work,

Nano piano concept: Arrays of gold, pillar-supported bowtie nanoantennas (bottom left) can be used to record distinct musical notes, as shown in the experimentally obtained dark-field microscopy images (bottom right). These particular notes were used to compose 'Twinkle, Twinkle, Little Star.'  Courtesy of University of Illinois at Urbana-Champaign

Nano piano concept: Arrays of gold, pillar-supported bowtie nanoantennas (bottom left) can be used to record distinct musical notes, as shown in the experimentally obtained dark-field microscopy images (bottom right). These particular notes were used to compose ‘Twinkle, Twinkle, Little Star.’ Courtesy of University of Illinois at Urbana-Champaign

A March 16, 2015 University of Illinois at Urbana-Champaign news release (also on EurekAlert), which originated the news item, describes the research in more detail (Note: Links have been removed),

To demonstrate its abilities to store sound and audio files, the researchers created a musical keyboard or “nano piano,” using the available notes to play the short song, “Twinkle, Twinkle, Little Star.”

“Data storage is one interesting area to think about,” Toussaint said. “For example, one can consider applying this type of nanotechnology to enhancing the niche, but still important, analog technology used in the area of archival storage such as using microfiche. In addition, our work holds potential for on-chip, plasmonic-based information processing.”

The researchers demonstrated that the pBNAs could be used to store sound information either as a temporally varying intensity waveform or a frequency varying intensity waveform. Eight basic musical notes, including middle C, D, and E, were stored on a pBNA chip and then retrieved and played back in a desired order to make a tune.

“A characteristic property of plasmonics is the spectrum,” said Hao Chen, a former postdoctoral researcher in Toussaint’s PROBE laboratory and the first author of the paper, “Plasmon-Assisted Audio Recording,” appearing in the Nature Publishing Group’s Scientific Reports. “Originating from a plasmon-induced thermal effect, well-controlled nanoscale morphological changes allow as much as a 100-nm spectral shift from the nanoantennas. By employing this spectral degree-of-freedom as an amplitude coordinate, the storage capacity can be improved. Moreover, although our audio recording focused on analog data storage, in principle it is still possible to transform to digital data storage by having each bowtie serve as a unit bit 1 or 0. By modifying the size of the bowtie, it’s feasible to further improve the storage capacity.”

The team previously demonstrated that pBNAs experience reduced thermal conduction in comparison to standard bowtie nanoantennas and can easily get hot when irradiated by low-powered laser light. Each bowtie antenna is approximately 250 nm across in dimensions, with each supported on 500-nm tall silicon dioxide posts. A consequence of this is that optical illumination results in subtle melting of the gold, and thus a change in the overall optical response. This shows up as a difference in contrast under white-light illumination.

“Our approach is analogous to the method of ‘optical sound,’ which was developed circa 1920s as part of the effort to make ‘talking’ motion pictures,” the team said in its paper. “Although there were variations of this process, they all shared the same basic principle. An audio pickup, e.g., a microphone, electrically modulates a lamp source. Variations in the intensity of the light source is encoded on semi-transparent photographic film (e.g., as variation in area) as the film is spatially translated. Decoding this information is achieved by illuminating the film with the same light source and picking up the changes in the light transmission on an optical detector, which in turn may be connected to speakers. In the work that we present here, the pBNAs serve the role of the photographic film which we can encode with audio information via direct laser writing in an optical microscope.”

In their approach, the researchers record audio signals by using a microscope to scan a sound-modulated laser beam directly on their nanostructures. Retrieval and subsequent playback is achieved by using the same microscope to image the recorded waveform onto a digital camera, whereby simple signal processing can be performed.

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

Plasmon-Assisted Audio Recording by Hao Chen, Abdul M. Bhuiya, Qing Ding, & Kimani C. Toussaint, Jr. Scientific Reports 5, Article number: 9125 doi:10.1038/srep09125 Published 16 March 2015

This is an open access paper and here is a sample recording courtesy of the researchers and the University of Illinois at Urbana-Champaign,

Acoustics and carbon nanotubes

Mikhail Koslov from the University of Texas at Dallas has written a Dec. 18, 2014 Nanowerk Spotlight article about his research into carbon nanotubes and their acoustic properties,

Carbon nanotube assemblies enabled design of a hybrid thermo-electromagnetic sound transducer with unique sound generation features that are not available from conventional diaphragm and thermo-acoustic speakers.

EM image of multi-walled carbon nanotube sheet used for thermo-electromagnetic sound transducer. (Image: Mikhail Kozlov, University of Texas at Dallas)

EM image of multi-walled carbon nanotube sheet used for thermo-electromagnetic sound transducer. (Image: Mikhail Kozlov, University of Texas at Dallas)

Kozlov goes on to explain his work in more detail,

… a hybrid thermo-electromagnetic sound transducer (TEMST) [was] fabricated using highly porous multi-walled carbon nanotube sheet that was placed in the proximity of a permanent magnet. Upon electrical AC excitation, thermal response of the material is combined with diaphragm-like sheet oscillations induced by the electromagnetic action of the Lorentz force.

Unlike conventional diaphragm loudspeaker, acoustic spectrum of the TEMST device consists of a superposition of TA and EM responses that can be altered by applied bias voltage. Variation of bias voltage changes spectral intensity and spatial distribution of generated sound.

In particular, propagation direction of the sound can be reversed by switching bias polarity that somewhat resembles voltage-controlled acoustic reflection. Such uncommon behavior was explained by interference of the two contributions being beneficial for diverse sound management applications.

It was found also that amplitude of first TEMST harmonic changes a lot with applied magnetic field, while the second one remains almost field independent. This unusual feature is convenient for magnetic sensing similar to that enabled by Lorentz force magnetometers. The magnetic field detection in the TEMST device is facilitated by the audio sensing system.

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

Thermo-electromagnetic sound transducer based on carbon nanotube sheet by Mikhail Kozlov and Jiyoung Oh. J. Appl. Phys. 116, 094301 (2014); http://dx.doi.org/10.1063/1.4894143 Published online Sept. 2, 2014

This paper is behind a paywall.

Shouting, booming, humming sands

There are sand dunes that make sounds that have been variously described as shouting, humming, singing, moaning, roaring, drumming, thunder, and more. The most poetic description of the phenomenon comes from Marco Polo (from a 2008 article by Bradley Hope in the New York Moon [http://www.nymoon.com/pubs/desert/singingsand/]),

Marco Polo wrote during his journey through the Desert of Lop that “it is asserted as well-known fact that this desert is the abode of many evil spirits, which amuse travellers to their destruction with most extraordinary illusions.” These spirits, or djinn, “at times fill the air with the sounds of all kinds of musical instruments, and also of drums and the clash of arms.”

There are 30 such spots in the world that feature the ‘singing sands’ and scientists are trying to figure out why. From the article by Hope,

Singing sand tends to be found in amphitheatre-shaped dunes on the steeper side that faces away from the wind. In Arabic, it is called za’eeq al raml, or “the shouting sand.” It starts as you walk over the edge of the crest, a swelling hum that picks up with each step. Before long the face of the dune is a single, vast musical instrument made up of millions of tumbling granules. The sand even quakes near your footsteps like the rapids on a river.

“It’s this wonderful symphony of sands,” said Farouk El-Baz, a scientist who helped design the Apollo missions in the 1960s. “It’s one layer of sand slipping over another. The grains touch each other in motion.”

There’s a little more detail and a 6 minute video at the March 30, 2011 posting by GrrlScientist on the Punctuated Equilibrium blog (http://www.guardian.co.uk/science/punctuated-equilibrium/2011/mar/31/1),

To “boom”, a sand dune must be at least 150 feet high, it must have loose, dry sand with a uniform particle size on its surface with a harder, moist layer of sand underneath that acts as a resonating chamber, and of course, it must produce a note that is within the range of human hearing — which makes me suspect that if humans had better hearing, we’d hear even more singing sand dunes. If this is the case, I’d guess that animals can hear more singing sand dunes than humans can.

Here’s a 30 second video snippet that features the sound the sands make,

The video at Punctuated Equilibrium features the scientist doing the research by the seat of their pants. Yes, they slide down the dunes so they can hear the singing and take measurements.

Happy Canada Day!

This will be a short one. My recent paper, ‘Nanotechnology, storytelling, sensing, and materiality‘, gave me a chance to explore the impact that various sensing technologies used for the nanoscale might have on storytelling. In one of those happy coincidences that can occur, I came across a new sensing technique (although strictly speaking it’s not applied at the nanoscale) that incorporates light and sound on Nanowerk News here. The new technique has allowed researchers to create three-dimensional whole body visualizations of zebra fish. From Nanowerk News,

The real power of the technique, however, lies in specially developed mathematical formulas used to analyze the resulting acoustic patterns. An attached computer uses these formulas to evaluate and interpret the specific distortions caused by scales, muscles, bones and internal organs to generate a three-dimensional image. The result of this “multi-spectral opto-acoustic tomography”, or MSOT, is an image with a striking spatial resolution better than 40 micrometers (four hundredths of a millimeter). And best of all, the sedated fish wakes up and recovers without harm following the procedure.

This new technique, MSOT, has applications for medical research.

In tangentially related news, Rob Annan’s posting on the ‘Don’t leave Canada behind‘ blog (June 30, 2009) features a few comments about a recent article in the New York Times that suggests current funding structures inhibit innovative cancer research. The report was written about US funding but Annan offers some thoughts on the matter and points the way to more Canadian commentary as well as the New York Times article.

That’s it. Happy Canada Day.

Nano motors in your ears, artificial tendons and public consultation in Europe

Researchers in Utah and Texas have learned that tiny tubes located on the hair cells inside our ears flex and change size to amplify sound. The researchers have coined a phrase for this, ‘flexoelectric motor’. They also compare the process to dancing and using a steering wheel in a car. The metaphors are a little mixed but I think I get the general idea. (From a writing perspective, there’s a tendency to throw a bunch of metaphors together to describe something either because no single metaphor is adequate or the writer got carried away.) For more about the ear discovery, go here.

If your tendons have ever been injured, you know that recovery is difficult and not assured so this news will be welcome. A student at the University of Manchester (UK) has developed an artificial tendon made of nanofibres, which can be grafted into the injured area. As the tendons repair themselves the artificial tendon degrades. Apparently it degrades safely as it’s made of a bio-polymer. I gather this type of polymer is used for other medical devices inserted in the body.  There’s more information here.

The European Commission has scheduled a one-day public nanotechnology consultation for Sept. 10, 2009, focusing on risk issues. The last day to submit comments prior to the meeting is June 19, 2009. They have have gathered information about nanotechnology and its risks in the past and this meeting builds on previous work. For more information, go here.