Transparent artificial muscle plays music

first_imgIn a materials science laboratory at Harvard, a transparent disk connected to a laptop fills the room with music — it’s the “Morning” prelude from “Peer Gynt” played on an ionic speaker.No ordinary speaker, it consists of a thin sheet of rubber sandwiched between two layers of a saltwater gel, and it’s as clear as glass. A high-voltage signal that runs across the surfaces and through the layers forces the rubber to rapidly contract and vibrate, producing sounds that span the entire audible spectrum, 20 hertz to 20 kilohertz.But this is not an electronic device, nor has it ever been seen before. As described in a paper published in the Aug. 30 issue of Science, it represents the first demonstration that electrical charges carried by ions, rather than electrons, can be put to meaningful use in fast-moving, high-voltage devices.“Ionic conductors could replace certain electronic systems; they even offer several advantages,” says co-lead author Jeong-Yun Sun, a postdoctoral fellow at the Harvard School of Engineering and Applied Sciences (SEAS).For example, ionic conductors can be stretched to many times their normal area without an increase in resistivity — a problem common in stretchable electronic devices. Secondly, they can be transparent, making them well-suited for optical applications. Thirdly, the gels used as electrolytes are biocompatible, so it would be relatively easy to incorporate ionic devices — such as artificial muscles or skin — into biological systems.Jeong-Yun Sun (left) and Christoph Keplinger show off an ionically conductive material that is very stretchy and completely transparent. Photo by Eliza Grinnell/SEAS CommunicationsAfter all, signals carried by charged ions are the electricity of the human body, allowing neurons to share knowledge and spurring the heart to beat. Bioengineers would love to mesh artificial organs and limbs with that system.“The big vision is soft machines,” said co-lead author Christoph Keplinger, who worked on the project as a postdoctoral fellow at SEAS and in the Department of Chemistry and Chemical Biology. “Engineered ionic systems can achieve a lot of functions that our body has: They can sense, they can conduct a signal, and they can actuate movement. We’re really approaching the type of soft machine that biology has to offer.”The audio speaker represents proof of concept for ionic conductors because producing sounds across the entire audible spectrum requires both high voltage (to squeeze hard on the rubber layer) and high-speed actuation (to vibrate quickly) — two criteria that are important for applications but that would have ruled out the use of ionic conductors in the past.The traditional constraints are well known: High voltages can set off electrochemical reactions in ionic materials, producing gases and burning up the materials. Ions are also much larger and heavier than electrons, so physically moving them through a circuit is typically slow. The system invented at Harvard overcomes both of these problems, opening up a vast number of potential applications including not just biomedical devices, but also fast-moving robotics and adaptive optics.“It must seem counterintuitive to many people, that ionic conductors could be used in a system that requires very fast actuation, like our speaker,” said Sun. “Yet by exploiting the rubber layer as an insulator, we’re able to control the voltage at the interfaces where the gel connects to the electrodes, so we don’t have to worry about unwanted chemical reactions. The input signal is an alternating current, and we use the rubber sheet as a capacitor, which blocks the flow of charge carriers through the circuit. As a result, we don’t have to continuously move the ions in one direction, which would be slow; we simply redistribute them, which we can do thousands of times per second.”Sun works in a research group led by Zhigang Suo, the Allen E. and Marilyn M. Puckett Professor of Mechanics and Materials at SEAS. An expert in the mechanical behaviors of materials, Suo is also a Kavli Scholar at the Kavli Institute for Bionano Science & Technology, which is based at SEAS.Suo teamed up with George M. Whitesides, a prominent chemist who specializes in soft machines, among many other topics. Whitesides is the Woodford L. and Ann A. Flowers University Professor in the Department of Chemistry and Chemical Biology, co-director of the Kavli Institute at Harvard, and a core faculty member at the Wyss Institute for Biologically Inspired Engineering at Harvard.“We’d like to change people’s attitudes about where ionics can be used,” said Keplinger, who now works in Whitesides’ research group. “Our system doesn’t need a lot of power, and you can integrate it anywhere you would need a soft, transparent layer that deforms in response to electrical stimuli — for example, on the screen of a TV, laptop, or smartphone to generate sound or provide localized haptic feedback — and people are even thinking about smart windows. You could potentially place this speaker on a window and achieve active noise cancellation, with complete silence inside.”Sam Liss, director of business development in Harvard’s Office of Technology Development, is working closely with the Suo and Whitesides labs to commercialize the technology. Their plan is to work with companies in a range of product categories, including tablet computing, smartphones, wearable electronics, consumer audio devices, and adaptive optics.“With wearable computing devices becoming a reality, you could imagine eventually having a pair of glasses that toggles between wide-angle, telephoto, or reading modes based on voice commands or gestures,” suggested Liss.For now, there is much more engineering and chemistry work to be done. The Harvard team chose to make its audio speaker out of very simple materials — the electrolyte is a polyacrylamide gel swollen with salt water — but they emphasize that an entire class of ionically conductive materials is available for experimentation. Future work will focus on identifying the best combinations of materials for compatibility, long life, and adhesion between the layers.In addition to Keplinger, Sun, Whitesides, and Suo, coauthors included Keith Choon Chiang Foo, a former postdoctoral fellow at SEAS, now at the Institute of High Performance Computing in Singapore; and Philipp Rothemund, a graduate student at SEAS.This research was supported by the National Science Foundation through a grant to the Materials Research Science and Engineering Center at Harvard University and by the Army Research Office. It was also enabled in part by the Department of Energy and the Agency for Science, Technology, and Research (A*STAR) in Singapore.last_img read more

Operator accuses Denmark of trying to delay Nord Stream 2 pipeline project

first_img‘Project delays to increase gas price levels’ Nord Stream 2 AG, a subsidiary of Russia’s Gazprom and operator of the Nord Stream 2 offshore gas pipeline, has submitted a third application for a route through Danish waters while accusing Denmark of making deliberate attempts to delay the project by asking for the third route option.The Pioneering Spirit vessel installing Nord Stream 2 in Swedish waters. Source: Nord Stream 2 AGThis third application for the pipeline route through Danish waters was submitted on Monday, April 15 more than two years after submitting the first application.The pipeline operator said on Monday that the third application, together with the Environmental Impact Assessment (EIA), covers a route in the Danish exclusive economic zone (EEZ) in the waters south of Bornholm. This application and the EIA has been submitted in accordance with the decision made by the Danish Energy Agency (DEA) on March 26, 2019.According to the operator, the EEZ border between Poland and Denmark was previously disputed and therefore the area was not available for any project developer. An agreement has been reached between the two countries, which, however, has not yet been ratified by Poland, the pipeline operator explained.Nord Stream 2 already has two pending applications with the DEA.Namely, in January 2018, the amended Danish Continental Shelf Act entered into force with retroactive effect only for the Nord Stream 2 project. The law gives the Danish Minister of Foreign Affairs the right to veto infrastructure projects running through territorial waters on political grounds. Such a judgement from the Ministry of Foreign Affairs has now been pending for 16 months. Nord Stream 2 AG has not received any response at all.In August 2018, after 8 months without any indication of the timing of the Minister of Foreign Affairs recommendation, Nord Stream 2 was therefore forced to apply for a second, alternative route outside Danish territorial waters, north-west of Bornholm through the Danish EEZ.Nord Stream 2 AG claims that both permitting processes, which included consultations with the public and expert authorities, nationally and internationally (the so-called Espoo procedure), have shown that all technical and environmental prerequisites are fulfilled and a construction permit could be granted for either route. ‘Denmark’s actions hinder freedom’ In the statement on Monday, Nord Stream 2 AG said: “For a project developer like Nord Stream 2 AG, it is incomprehensible why there has still been no decision on the route through territorial waters after 16 months since entry into force of the amended Danish Continental Shelf Act, and why there has been no decision on the route north-west of Bornholm even though there have been and are no relevant environmental or safety objections against this route. Asking for a third route option to be developed, despite two fully processed, ready-to-be-permitted applications on the table, can only be seen as a deliberate attempt to delay the project’s completion.“Irrespective of its own starkly different legal assessment, Nord Stream 2 AG is now forced to submit this third application as a mitigation measure. Any project developer and investor on the whole depend on a predictable, stable and transparent regulatory framework and such actions from Denmark not only undermine fundamental Danish constitutional and European law principles of legitimate expectations and legal certainty but also hinder freedom of laying the submarine pipes in exclusive economic zones as set out in UNCLOS 1982 and as such is not compliant with the good faith principle required by UNCLOS 1982.”Gazprom as the shareholder as well as five major European energy companies as financial investors from Austria, France, Germany and the Netherlands back the project. Committed investments currently equal almost all of the project’s CAPEX. Globally, more than 670 companies from 25 countries are involved in the project.Nord Stream 2 gas project map; Source: Nord Stream 2 AG Nord Stream 2 AG emphasized that studies had shown that in the case of a delay of the project, lack of access to competitive gas supplies would increase price levels throughout Europe. European families and industries will foot the bill of at least 20 million euros – for every day of delay, the operator said.In accordance with the permits in four countries, work on the Nord Stream 2 pipeline is ongoing in Russia, Finland, Sweden and Germany. More than 1,000 kilometers, approximately the distance from Copenhagen to Paris, of the two lines have been laid.Nord Stream 2 was designed as two parallel 48 inch lines, roughly 1,200 kilometers long, each starting from south-west of St Petersburg and ending at German coast, Greifswald. Nord Stream 2’s natural gas pipelines will have the capacity to transport 55 billion cubic meters (bcm) of Russian gas a year to the EU, for at least 50 years.Denmark is not the only country where the giant pipeline project has faced obstacles. Namely, the Nord Stream 2 gas pipeline project has been under fire from the European Parliament as well as a number of U.S. senators last December who called for its cancellation due to security reason.The project has been seen by some as a threat to the EU energy security, making the union vulnerable to reliance on Russian gas, and it also bypasses Ukraine in moving Russian gas to Europe.In addition to opposition from the EP, over 40 U.S. senators have also called for the cancellation of the Nord Stream 2 pipeline.In more recent news, the U.S. political journal Politico reported last Thursday that the U.S. Ambassador to the EU, Gordon Sondland, had criticized the European Commission for not putting more effort into killing the Nord Stream 2 pipeline.Furthermore, Reuters reported on Thursday that the construction of the pipeline was bound to face more delays, forcing Moscow to come to an agreement with Ukraine on future gas transits.Offshore Energy Today StaffSpotted a typo? Have something more to add to the story? Maybe a nice photo? Contact our editorial team via email. Offshore Energy Today, established in 2010, is read by over 10,000 industry professionals daily. We had nearly 9 million page views in 2018, with 2.4 million new users. This makes us one of the world’s most attractive online platforms in the space of offshore oil and gas and allows our partners to get maximum exposure for their online campaigns. If you’re interested in showcasing your company, product or technology on Offshore Energy Today contact our marketing manager Mirza Duran for advertising options.last_img read more

Real Reject Tottenham Attempt To Offload Adebayor In Bale Deal

first_imgAccording to the Daily Mail Tottenham chairman Daniel Levey was hoping to sell Adebayor to the Spanish club as part of the deal that is being negotiated for Bale.The article reveals that Adebayor was offered by Levy to Perez when the two men met earlier this week to discuss a possible transfer of the Welsh forward.It appears that Spurs want to get rid of Adebayor and were therefore prepared to throw him into a deal for another player.The same article reveals that Adebayor is currently on leave from Tottenham as he is attending the funeral of his brother.However, it is reported that Togo international may not return to White Hart Lane due to his relationship with manager Villas-Boas having deteriorated significantly since the end of last season.However, despite rumours that Adebayor will quit Tottenham this summer he has featured in Tottenham’s pre-season matches. The striker played in the 0-0 draw at Colchester and was also present in Hong Kong when Tottenham lost 3-1 to Sunderland.last_img read more