The various shapes are in contrast with the liquid drops which can splash, spread or bounce upon hitting a surface. Successive drops freeze rapidly upon impact due to the drainage of a small fraction of liquid, literally stacking on top of each other into surprisingly slender structures know as granular towers.
Dripping a mixture of sand and water onto an absorbent surface can lead to striking structures of a wide variety of striking forms. Credit: Image courtesy of Julien Chopin and Arshad Kudrolli
In addition, twisted pagoda dome-like structures result upon increasing the flow rate of the damp granular mixture. Experiments show that the towers are held together because of capillary and friction forces, and the shape of the towers depends on a subtle balance between dripping frequency, density of grains, and impact speed. Besides applications in surface patterning, this tower building technique may be a new and easy way to probe the flow properties of dense granular suspensions by observing the shapes of the towers they produce.Peering Out from Under an Invisibility Cloak
Most invisibility cloak designs have one serious drawback - they make it impossible for anyone hiding under the cloak to see what's going on in the outside world. Researchers have now come up with an approach that, in theory, should allow us to make cloaks that allow you to peek out while remaining entirely hidden. In effect, they propose making a tiny tear in the cloak, and then stitching the hole with a two types of materials chosen to effectively cancel each other out when seen from the outside, while still allowing light to enter. Although the cloak design currently exists only on paper, it theoretically ensures that aspiring Harry Potters remain entirely undetectable while keeping an eye on the Voldemorts and Snapes all around them.
James Riordon | EurekAlert!
Water without windows: Capturing water vapor inside an electron microscope
13.12.2017 | Okinawa Institute of Science and Technology (OIST) Graduate University
Columbia engineers create artificial graphene in a nanofabricated semiconductor structure
13.12.2017 | Columbia University School of Engineering and Applied Science
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
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