Tag Archives: Afrofuturism

3-D underwater acoustic carpet cloak

Who can resist a ‘Black Panther’ reference (Wikipedia Black Panther film entry)? Certainly not me. Scientists from the Chinese Academy of Sciences made this June 4, 2018 announcement (also on EurekAlert),

Cloaking is one of the most eye-catching technologies in sci-fi movies. In two 2018 Marvel films, Black Panther and Avengers: Infinity War, Black Panther conceals his country Wakanda, a technologically advanced African nation, from the outside world using the metal vibranium.

However, in the real world, if you want to hide something, you need to deceive not only the eyes, but also the ears, especially in the underwater environment.

Recently, a research team led by Prof. YANG Jun from the Institute of Acoustics (IOA) of the Chinese Academy of Sciences designed and fabricated a 3D underwater acoustic carpet cloak (UACC) using transformation acoustics.

The research was published online in Applied Physics Letters on June 1 [2018].

Like a shield, the carpet cloak is a material shell that can reflect waves as if the waves were reflecting off a planar surface. Hence, the cloaked target becomes undetectable to underwater detection instruments like sonar.

Using transformation acoustics, the research team first finished the 2D underwater acoustic carpet cloak with metamaterial last year (Scientific Reports, April 6, 2017). However, this structure works only in two dimensions, and becomes immediately detectable when a third dimension is introduced.

To solve this problem, YANG Jun and his IOA team combined transformation acoustics with a reasonable scaling factor, worked out the parameters, and redesigned the unit cell of the 2D cloak. They designed the 3D underwater acoustic carpet cloak and then proposed a fabrication and assembly method to manufacture it. The 3D cloak can hide an object from top to bottom and deal with complex situations, such as acoustic detection in all directions.

The 3D underwater acoustic carpet cloak is a pyramid comprising eight triangular pyramids; each triangular pyramid is composed of 92 steel strips using a rectangle lattice, similar to a wafer biscuit. More vividly, if we remove the core from a big solid pyramid, we can hide something safely in the hollow space left.

“To make a 3D underwater acoustic carpet cloak, researchers needed to construct the structure with 2D period, survey the influence of the unit cell’s resonance, examine the camouflage effect at the ridge of the sample, and other problems. In addition, the fabrication and assembly of the 3D device required more elaborate design. The extension of the UACC from 2D to 3D represents important progress in applied physics,” said YANG.

In experimental tests, a short Gaussian pulse propagated towards the target covered with the carpet cloak, and the waves backscattered toward their origin. The cloaked object successfully mimicked the reflecting surface and was undetectable by sound detection. Meanwhile, the measured acoustic pressure fields from the vertical view demonstrated the effectiveness of the designed 3D structure in every direction.

“As the next step, we will try to make the 3D underwater acoustic carpet cloak smaller and lighter,” said YANG.

Funding for this research came from the National Natural Science Foundation of China (Grant No.11304351, 1177021304), the Youth Innovation Promotion Association of CAS (Grant No. 2017029), and the IACAS Young Elite Researcher Project (Grant No. QNYC201719).

Prof. YANG Jun and Dr. JIA Han led the research team from the Institute of Acoustics (IOA) of the Chinese Academy of Sciences. Prof. YANG Jun engages in research on sound, vibration and signal processing, and especially sound field control and array signal processing. They also work on other devices based on metamaterial in order to manipulate the propagation of sound waves.

A model of the device,

Caption: This is a model and photograph of the 3D underwater acoustic carpet cloak composed of over 700 steel strips. Credit: IOA

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

Experimental demonstration of three-dimensional broadband underwater acoustic carpet cloak by Yafeng Bi, Han Jia, Zhaoyong Sun, Yuzhen Yang, Han Zhao, and Jun Yang.
Appl. Phys. Lett. 112, 223502 (2018); https://doi.org/10.1063/1.5026199 Published Online: June 2018

This paper is open access.

Afrofuturism in the UK’s Guardian newspaper and as a Future Tense Dec. 2015 event

My introduction to the term, Afrofuturism was in a March 11, 2015 posting by Jessica Bland for the Guardian in the Technology/Political Science section. It was written on the occasion of a then upcoming FutureFest event,

This is unapologetically connected to FutureFest, the festival Nesta (where I work) is holding this weekend in London Bridge. These thoughts represent the ideas that piqued my interest while curating talks and exhibits based on the thought experiment of a future African city-superpower. George Clinton, Spoek Mathambo, Tegan Bristow and Fabian-Carlos Guhl (from Ampion Venture Bus) will be speaking during the weekend. Thomas Aquilina is displaying photographs from his trip and the architects of the Lagos 2060 project will take part in a debate on whether their fiction can lead to a different kind of future.

In anticipation of the March 2015 FutureFest event, Bland had  written a roundup piece about “New sounds from South Africa and Nigeria’s urban science fiction [that] could change the future of technology and the city.” Here are some excerpts from her piece (Note: Links have been removed),

Strong stories or visions of the future stick around. The 1920s sci-fi fantasy of a jetpack commute still pops up in discussions about the future of technology, not to mention as an option on the Citymapper travel app. By co-opting or creating new visions of the future, it seems possible to influence the development of new products and services – from consumer tech to urban infrastructure. A new generation of African artists is taking over the mantle of Afrofuturist arts from a US-centred crowd. They could bring a welcome change to how technology is developed in the region, as well as a challenge to the dominance of imported plans for urban development.

Last Thursday’s London gig from Fantasma was sweaty and boisterous. It was also very different from the remix of Joy Division’s She’s Lost Control that brought front man Spoek Mathambo to the attention of a global audience a couple of years ago. Fantasma is a group of South African musicians with different backgrounds. Guitarist Bhekisenzo Cele started the gig with three of his own songs, introducing the traditional Zulu maskandi music that they went on to mix with shangaan electro, hiphop, punk, electronica and everything in between.

The gig had a buzz about it. But the performance was from a new collective trying things out; it wasn’t as genre-smashing as expected. And expectations ride high for Spoek. In 2011, he titled a collection from his back catalogue ‘Beyond Afrofuturism’. He took on, at least in name, a whole Afro-American cultural movement: embodied by musicians like Sun Ra, George Clinton and Drexciya. A previous post on this blog by Chardine Taylor-Stone describes the roots of Afrofuturism in science fiction that centres on space travel and human enhancement. But she goes on to say: “Afrofuturism also goes beyond spaceships, androids and aliens, and encompasses African mythology and cosmology with an aim to connect those from across the Black Diaspora to their forgotten African ancestry.” Spoek shares what he calls a cultural lineage with this movement. But he is not Afro-American. He also shares a cultural lineage with the sounds of South African musicians he grew up listening to.

Other forms of art are taking an increasingly activist role in the future of technology. Lydia Nicholas’s description of the relationship between Douglas Adam’s fictional Hitchhiker’s Guide and the real life development of the iPad shows how science fiction can effortlessly influence the development of new technology.

The science fiction collection Lagos 2060 is a more purposeful intervention. Published in 2013, it speculates about what it will be like to live in Lagos 100 years after Nigeria gained independence from the UK. It was born out of a creative writing workshop initiated by DADA books in Lagos. Foundation director of DADA, Ayodele Arigbabu, described the collection and other similar video and visual art work (in an email): “Far more than aesthetic indulgence, these renditions are a calibration of the changes deemed necessary in today’s political, technical and cultural infrastructure.”

Bland also explores a history of this movement,

Gaston Berger was the Senegalese founder of the academic journal Prospectiv in 1957. To many, he was the first futurist, or at least one of the first people to describe themselves as one. He founded promotes the practice of playing out the human consequences of today’s action. This is about avoiding a fatalistic approach to the future: about being proactive and provoking change, as much as anticipating it.

Berger’s early work spawned a generation, and then another and another, of professional futurists. They work in different ways and different places. Some are in government, enticing and frightening politicians with the prospect of a different transport system, healthcare sector or national security regime. Some are consultants to large companies, offering advice on the way that trends like 3D printing or flying robots will change their sector. An article from 1996 does a good job of summarising the principles of this movement: don’t act like an ostrich and ignore the future by putting your head in the sand; don’t act like a fireman and just respond to threats to your future; and don’t focus just on insurance against for the future.

Bland has written an interesting and sprawling piece, which in some way reflects the subject. Africa is a huge and sprawling continent.

Slate, a US online magazine, is hosting along with New America and Arizona State University a Future Tense event on Afrofuturism but this seems to be quite US-centric. From the Future Tense Afrofuturism event webpage on the Slate website (Note: Links have been removed),

Future Tense is hosting a conversation about Afrofuturism in New York City on December 3rd, 2015 from 6:30-8:30 p.m.

Afrofuturism emphasizes the intersection of black cultures with questions of imagination, liberation, and technology. Rooted in works like those of science fiction author Octavia Butler, avant-garde jazz legend Sun Ra, and George Clinton, Afrofuturism explores concepts of race, space and time in order to ask the existential question posed by critic Mark Dery: “Can a community whose past has been deliberately erased imagine possible futures?”

Will the alternative futures and realities Afrofuturism describes transform and reshape the concept of black identity? Join Future Tense for a discussion on Afrofuturism and its unique vantage on the challenges faced by black Americans and others throughout the African diaspora.

During the event, enjoy an Afrofuturist inspired drink from 67 Orange Street. Follow the discussion online using #Afrofuturism and by following @NewAmericaNYC and @FutureTenseNow.

Click here to RSVP. Space is limited so register now!

PARTICIPANTS

Michael Bennett
Principal Investigator, School for the Future of Innovation in Society, Arizona State University
@MGBennett

Ytasha Womack
Author, Afrofuturism: The World of Black Sci-Fi and Fantasy Culture and Post Black: How A New Generation is Redefining African American Identity
@ytashawomack

Juliana Huxtable
DJ and Artist
@HUXTABLEJULIANA

Walé Oyéjidé
Designer and Creative Director, Ikire Jones
@IkireJones

Aisha Harris
Staff writer, Slate
@craftingmystyle

It seems we have one word, Afrofuturism, and two definitions. One where Africa is referenced and one where African-American experience is referenced.

For anyone curious about Nesta, where Jessica Bland works and the Future Fest host (from its Wikipedia entry),

Nesta (formerly NESTA, National Endowment for Science, Technology and the Arts) is an independent charity that works to increase the innovation capacity of the UK.

The organisation acts through a combination of practical programmes, investment, policy and research, and the formation of partnerships to promote innovation across a broad range of sectors.

That’s it for now.