Man Dies. Come From Darkness, Into Darkness He Returns, And Is Reabsorbed, Without A Trace Left, Into

Making glass invisible: A nanoscience-based disappearing act

If you have ever watched television in anything but total darkness, used a computer while sitting underneath overhead lighting or near a window, or taken a photo outside on a sunny day with your smartphone, you have experienced a major nuisance of modern display screens: glare. Most of today’s electronics devices are equipped with glass or plastic covers for protection against dust, moisture, and other environmental contaminants, but light reflection from these surfaces can make information displayed on the screens difficult to see.

Now, scientists at the Center for Functional Nanomaterials (CFN) – a U.S. Department of Energy Office of Science User Facility at Brookhaven National Laboratory – have demonstrated a method for reducing the surface reflections from glass surfaces to nearly zero by etching tiny nanoscale features into them.

Whenever light encounters an abrupt change in refractive index (how much a ray of light bends as it crosses from one material to another, such as between air and glass), a portion of the light is reflected. The nanoscale features have the effect of making the refractive index change gradually from that of air to that of glass, thereby avoiding reflections. The ultra-transparent nanotextured glass is antireflective over a broad wavelength range (the entire visible and near-infrared spectrum) and across a wide range of viewing angles. Reflections are reduced so much that the glass essentially becomes invisible.

Read more.

Good vibrations no longer needed for speakers as research encourages graphene to talk

A pioneering new technique that encourages the wonder material graphene to “talk” could revolutionise the global audio and telecommunications industries.

Researchers from the University of Exeter have devised a ground-breaking method to use graphene to generate complex and controllable sound signals. In essence, it combines speaker, amplifier and graphic equaliser into a chip the size of a thumbnail.

Traditional speakers mechanically vibrate to produce sound, with a moving coil or membrane pushing the air around it back and forth. It is a bulky technology that has hardly changed in more than a century.

This innovative new technique involves no moving parts. A layer of the atomically thin material graphene is rapidly heated and cooled by an alternating electric current, and transfer of this thermal variation to the air causes it to expand and contract, thereby generating sound waves.

Read more.

For her performance in Gone with the Wind (1939), Hattie McDaniel won a Best Supporting Actress Oscar on February 29, 1940. She was the first African American to win an Academy Award.

You must stay drunk on writing so reality cannot destroy you.

Ray Bradbury, Zen in the Art of Writing (via books-n-quotes)

“She has autonomy. She has a strong will. But she can’t move. So in many ways her life is my life. It’s bigger than me, it controls me, and it makes me fight like never before. We spend so much time together that she’s a part of me. She knows how important she is to me. She had childhood cancer. Her heart failed three times. And I was by her side the entire time. I never realized that I could love someone as much as this. She could never hurt me. She could never hurt anyone. We always ask her: ‘Are you angry?’, ‘Are you mad?’ And she always says ‘no.’ She laughs when I laugh. And right now I’m trying not to cry. Because she’ll cry if I cry.” (São Paulo, Brazil)

Building microfluidic circuits is generally a multi-day process, requiring a clean room and specialized manufacturing equipment. A new study suggests a quicker alternative using fluid walls to define the circuit instead of solid ones. The authors refer to their technique as “Freestyle Fluidics”. As seen above, the shape of the circuit is printed in the operating fluid, then covered by a layer of immiscible, transparent fluid. This outer layer help prevent evaporation. Underneath, the circuit holds its shape due to interfacial forces pinning it in place. Those same forces can be used to passively drive flow in the circuit, as shown in the lower animation, where fluid is pumped from one droplet to the other by pressure differences due to curvature. Changing the width of connecting channels can also direct flow in the circuits. This technique offers better biocompatibility than conventional microfluidic circuits, and the authors hope that this, along with simplified manufacturing, will help the technique spread. (Image and research credit: E. Walsh et al., source)

Fluid systems can sometimes serve as analogs for other physical phenomena. For example, bouncing droplets can recreate quantum effects and a hydraulic jump can act like a white hole. In this work, a bathtub vortex serves as an analog for a rotating black hole, a system that’s extremely difficult to study under normal circumstances. In theory, the property of superradiance makes it possible for gravitational waves to extract energy from a rotating black hole, but this has not yet been observed. A recent study has, however, observed superradiance for the first time in this fluid analog.

To do this, the researchers set up a vortex draining in the center of a tank. (Water was added back at the edges to keep the depth constant.) This served as their rotating black hole. Then they generated waves from one side of the tank and observed how those waves scattered off the vortex. The pattern you see on the water surface in the top image is part of a technique used to measure the 3D surface of the water in detail, which allowed the researchers to measure incoming and scattered waves around the vortex. For superradiance to occur, scattered waves had to be more energetic after interacting with the vortex than they were before, which is exactly what the researchers found. Now that they’ve observed superradiance in the laboratory, scientists hope to probe the process in greater detail, which will hopefully help them observe it in nature as well. For more on the experimental set-up, see Sixty Symbols, Tech Insider UK, and the original paper. (Image credit: Sixty Symbols, source; research credit: T. Torres et al., pdf; via Tech Insider UK)