Posted: 23 Mar 2012 05:01 PM PDT
Harvesting energy from the environment
Robojelly is still in the initial stages of development so it still has a ways to go, but the finished concept is for a device that can supply its own energy through a reaction between oxygen and hydrogen in seawater, using platinum as a catalyst. The reaction creates enough energy in the form of heat to operate the robot’s propulsion system, without the need for batteries or any external fuel source.
Biomimicry and undersea propulsion
Robojelly's movements have little of the stiffness usually associated with robotic movement. As described somewhat poetically by Alaska Dispatch reporter Doug O'Harra, "It oozes. It glides. It pulses to a waltz-like beat."
Somewhat less poetically, the secret behind Robojelly's natural-looking movement is the result of a type of actuator (an actuator is a motor that operates robotic systems) made from a "smart material" developed at Virginia Tech.
Smart materials are beginning to emerge as players in the world of energy efficient movement. They are capable of changing shape and springing back to their original form, typically when stimulated by a chemical reaction that creates heat.
Virginia Tech’s material is called Bio-Inspired Shape Memory Alloy Composite (BISMAC). According to the project’s research abstract published in the Institute of Physics' Smart Materials and Structures journal, it consists of:
"…nano-platinum catalyst-coated multi-wall carbon nanotube sheets, wrapped on the surface of nickel–titanium shape memory alloy (SMA). As a mixture of oxygen and hydrogen gases makes contact with the platinum, the resulting exothermic reaction activates the nickel–titanium-based SMA. The sheets serve as a support for the platinum particles and enhance the heat transfer due to the high thermal conductivity between the composite and the SMA."
This complicated set-up enables Robojelly to mimic the muscular contractions of a real jellyfish, which jet-propels itself by enclosing water within its bell-shaped body, then expelling it with force.
Given the Navy's history of using dolphins for mine detection, the deployment of robotic jellyfish for military purposes is not all that far fetched. As for peacetime work, Robojelly could find itself detailed for environmental surveillance, monitoring and reporting on the condition of underwater equipment, and search-and-rescue operations.
Posted: 23 Mar 2012 03:49 PM PDT
First thing to note: “German power consumption peaks twice a day, roughly between 12 noon and 1 PM and then later in the evening at around 8 PM,” Craig Norris of Renewables International writes, in a story translated from a Photon (German) article.
Now, while demand dips in between those peaks, it doesn’t go so low as in the dead of night. As such, this is was an electricity spot market price graph from March 2008:
While electricity prices rise in the early morning (4am to 8am) as demand rises, from about 8am to 9pm, the price is pretty level.
Now, fast forward to March 2012:
We again see prices rise from the early morning to about 8 or 9am, but then look at what happens when the sun (and its 25 GW of power capacity from solar panels) kick in — the price drops off a cliff, diving even deeper than the price of electricity in the dead of night!
Basically, simple supply and demand tells you that supply kicks in at around the same time demand kicks in, making electricity prices lower than they would be if supply didn’t grow like that.
Now, something else to note is that nighttime prices are quite a bit higher in 2012 than in 2008, nearly twice as high! Craig notes: “Given that baseload demand has hardly changed, it must be assumed that power companies are charging more in times of lower demand now that they cannot make their old profits during daylight hours.” Hmm…
One last thought: we, humans, generally wake with the sun and sleep when the sun goes down (OK, very generally these days, but it’s still the general pattern). Doesn’t it make sense to match our electricity source with that sun a bit more? Of course it does, as the graph above helps to show. Thomas Edison would have been proud (and making good money off of his forethought):
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