Borrowing a trick from nature, engineers from the University of California at Berkeley have created an incredibly thin, chameleon-like material that can be made to change color — on demand — by simply applying a minute amount of force.

This new material-of-many-colors offers intriguing possibilities for an entirely new class of display technologies, color-shifting camouflage, and sensors that can detect otherwise imperceptible defects in buildings, bridges, and aircraft.

“This is the first time anybody has made a flexible chameleon-like skin that can change color simply by flexing it,” said Connie J. Chang-Hasnain, a member of the Berkeley team and co-author on a paper published today in Optica, The Optical Society’s (OSA) new high-impact journal.

By precisely etching tiny features — smaller than a wavelength of light — onto a silicon film one thousand times thinner than a human hair, the researchers were able to select the range of colors the material would reflect, depending on how it was flexed and bent.

The colors we typically see in paints, fabrics, and other natural substances occur when white, broad spectrum light strikes their surfaces. The unique chemical composition of each surface then absorbs various bands, or wavelengths of light. Those that aren’t absorbed are reflected back, with shorter wavelengths giving objects a blue hue and longer wavelengths appearing redder and the entire rainbow of possible combinations in between. Changing the color of a surface, such as the leaves on the trees in autumn, requires a change in chemical make-up.


Recently, engineers and scientists have been exploring another approach, one that would create designer colors without the use of chemical dyes and pigments. Rather than controlling the chemical composition of a material, it’s possible to control the surface features on the tiniest of scales so they interact and reflect particular wavelengths of light. This type of “structural color” is much less common in nature, but is used by some butterflies and beetles to create a particularly iridescent display of color.


Controlling light with structures rather than traditional optics is not new. In astronomy, for example, evenly spaced slits known as diffraction gratings are routinely used to direct light and spread it into its component colors. Efforts to control color with this technique, however, have proved impractical because the optical losses are simply too great.


The authors of the Optica paper applied a similar principle, though with a radically different design, to achieve the color control they were looking for. In place of slits cut into a film they instead etched rows of ridges onto a single, thin layer of silicon. Rather than spreading the light into a complete rainbow, however, these ridges — or bars — reflect a very specific wavelength of light. By “tuning” the spaces between the bars, it’s possible to select the specific color to be reflected. Unlike the slits in a diffraction grating, however, the silicon bars were extremely efficient and readily reflected the frequency of light they were tuned to.


Earlier efforts to develop a flexible, color shifting surface fell short on a number of fronts. Metallic surfaces, which are easy to etch, were inefficient, reflecting only a portion of the light they received. Other surfaces were too thick, limiting their applications, or too rigid, preventing them from being flexed with sufficient control.


The Berkeley researchers were able to overcome both these hurdles by forming their grating bars using a semiconductor layer of silicon approximately 120 nanometers thick. Its flexibility was imparted by embedding the silicon bars into a flexible layer of silicone. As the silicone was bent or flexed, the period of the grating spacings responded in kind.


The semiconductor material also allowed the team to create a skin that was incredibly thin, perfectly flat, and easy to manufacture with the desired surface properties. This produces materials that reflect precise and very pure colors and that are highly efficient, reflecting up to 83 percent of the incoming light.


Their initial design, subjected to a change in period of a mere 25 nanometers, created brilliant colors that could be shifted from green to yellow, orange, and red – across a 39-nanometer range of wavelengths. Future designs, the researchers believe, could cover a wider range of colors and reflect light with even greater efficiency.

Source: www.eurekalert.org

See on Scoop.itCommunication design

In 1939, visitors stood in line for hours to see the Futurama exhibit at the New York World’s Fair, a detailed model imagining 1960s America. Complete with half a million tiny buildings and a million handmade miniature trees, it also visualized a network of highways crossing the country. And while the interstate system probably would have been built without it, it’s arguable that the visualization—sponsored by GM—helped the roads happen.

A new exhibit called the Future City, up now at London’s Royal Institute of British Architects, looks at how drawings and models of futuristic cities can shape the cities that actually are built.

“Visualizations of future cities contribute to our collective imagination,” says Nick Dunn from Lancaster University “They provide us with visionary projections of how we might live. Reexamining these from a historical perspective can give us new insights and greater understanding of the developments and patterns that shape the present, and in turn, their implications for our future.”

Source: www.fastcoexist.com

See on Scoop.itCommunication design

LEARNing To LEARN, the PracTICE | With ALL that mass of information which WE get on each day in OUR technology driven Digital World, with the messages from Social Media through OUR  PLN (Personal [Professional] Learning Network), there is a MUST to organize OUR LEARNing! WE MUST unlearn the OLD and learn to learn differently as that was the case twenty years ago!


Learn more:


– https://gustmees.wordpress.com/2015/01/28/practice-learning-to-learn-example-2/


– https://gustmees.wordpress.com/2014/10/11/learning-to-become-a-good-digital-citizen-digital-citizenship/


– https://gustmees.wordpress.com/2014/07/10/education-collaboration-and-coaching-the-future/



Source: gustmees.wordpress.com

See on Scoop.itCommunication design

Social media is often used for personal expression; to show special interests, proud moments, something informative, and personal statements. Social media accounts can be an extension of who were are. We live in a time where we can reach more people than in person. It can be tempting to tell everyone everything…

Source: www.dailyinfographic.com

See on Scoop.itCommunication design

Mexico City-based BuBa Arquitectos proposes a vertical zoo wrapped in lush vegetation that relies on solar power, rainwater and natural ventilation.

Why not take the same theories and technologies used to grow organic produce and raise animals and apply them to build more compact, more sustainable zoos? Proposed by Mexico City-based BuBa Arquitectos, the Vertical Zoo is a balanced and sustainable space where people and animals can coexist in harmony. Wrapped in lush vegetation, the star-shaped building makes use of green building strategies to reduce heat gain, encourage natural ventilation and soak up rainwater. Totally self-sufficient, the tower’s aim is to be a sustainable refuge for all animal kingdom species.

Source: inhabitat.com

See on Scoop.itCommunication design