Evaporation is a ubiquitous phenomenon in the natural environment and a dominant form of energy transfer in the Earth’s climate. Engineered systems rarely, if ever, use evaporation as a source of energy, despite myriad examples of such adaptations in the biological world. Evaporation-driven engines can power common tasks like locomotion and electricity generation. These engines start and run autonomously when placed at air–water interfaces. They generate rotary and piston-like linear motion using specially designed, biologically based artificial muscles responsive to moisture fluctuations. Using these engines, an electricity generator that rests on water can harvesting its evaporation to power a miniature car (weighing 0.1 kg) that moves forward as the water in the car evaporates. Evaporation-driven engines may find applications in powering robotic systems, sensors, devices and machinery that function in the natural environment.
Tempescope is a physical weather display that visualizes the weather by actually reconstructing the weather conditions inside a box.
A glimpse of the new disruptive technology introduced by Grabit, ‘Electroadhesion’ for the material handling industry. Electroadhesion can introduce a “stickyness” in just about anything that you can turn on and off whenever you want. It’s sort of like duct tape that comes with a toggle switch. The flexible bits are electrodes that generate alternating positive and negative charges, inducing opposite (i.e. attractive) charges in whatever they’re close to (anything at all, conductive or not), causing them to stick. Like geckotape, electrostatics depend on a lot of surface contact to adhere well, which is a problem if you’re trying to attach to surfaces that aren’t flat. Grabit’s “fingered” gripper is compliant enough to get around that issue.
At SRI International, in Menlo Park, California, researchers have developed a robot that is capable of climbing up almost any kind of wall, smooth, flat, or otherwise. Here, Harsha Prahlad, an SRI research engineer, explains the system, which operates under a principle known as electroadhesion.
A new phase-changing material built from wax and foam developed by researchers at MIT is capable of switching between hard and soft states.
Robots built from this material would be able to operate more like biological systems with applications ranging from difficult search and rescue operations, squeezing through rubble looking for survivors, to deformable surgical robots that could move through the body to reach a particular point without damaging any of the organs or vessels along the way.
Researchers at NC State have developed a new method to control the interfacial energy of a liquid metal via electrochemical deposition (or removal) of an oxide layer on its surface using ~1 volt.
Liquid metals have very large surface tension and therefore typically adopt a spherical shape. Surfactants, like soap, can lower the interfacial tension between two dissimilar liquids (for example, water and oil), but have negligible impact on the large interfacial tensions of liquid metal. Unlike conventional surfactants, the approach here can tune the interfacial tension of a metal significantly (from ~7x that of water to near zero), rapidly, and reversibly using only modest voltages. These properties can be harnessed to induce new electrohydrodynamic phenomena for manipulating liquid metal alloys based on gallium, which may enable shape-reconfigurable metallic components in electronic, electromagnetic, and microfluidic devices without the use of toxic mercury. The results also suggest that oxides—which are ubiquitous on most metals and semiconductors—may be harnessed to lower interfacial energy between dissimilar materials.