Years ago, I remember reading about supercapacitor electrodes made from what would be waste hemp bast fiber. They used graphene as a control. And IIRC, the natural branching structure in hemp (the strongest natural fiber) was considered ideal for an electrode.
How do the costs and performance compare? Graphene, hemp, durian, jackfruit
While graphene production costs have fallen due to lots of recent research, IIUC all graphene production is hazardous due to graphene's ability to cross the lungs and the blood-brain barrier?
All my life, I've heard people go on and on about the magical properties of hemp.
It's hilarious.
They have these material science level arguments about hemp, yet the same people would be hard pressed to find an alternative use for cotton aside from clothes, or wood pulp aside from ikea furniture.
It's a desert topping, it's a driveway sealant. And the government won't let us have it!
I was recently reading a book about Thomas Edison and it mentioned how he sent people all around the world searching for plant fibers that they could use as the filament in light bulbs. IIRC, they settled on a type of bamboo because the structure of the fibers were particularly conducive to their purposes.
Turns out UC Berkeley's got an approach for brewing cannabinoids (and I think terpenes) from yeast, and a company in Germany has a provisional patent application to brew cannabinoids from bacteria. We could be absorbing carbon ("sequestering" carbon) and coal ash acid rain with mostly fields of industrial hemp for which there are indeed thousands of uses.
The article seems like it was written for a high school news paper. It's a shame because it seems like there is real research going on that doesn't depend on the smell of durian or what Anthony Bourdain thought of it.
If you take a charged parallel plate capacitor and pull the plates farther apart does the energy in the system go up or down?
The equations seem to be geared to how distance affects how much you can charge a capacitor. But if it’s already holding a given charge, I don’t think the basic equation applies.
Stored energy goes up. That energy comes from the work done to pull the plates apart (since there is a static electric force attracting them to each other)
As long the capacitors have a width much larger than the distance between them, the energy stored is (if I recall correctly) linear. this is because the electric field is a constant vector field between the plates.
Once that is not true, you will transition to just separating two charged objects. Use Coulombs law to figure out the force. (Work energy is integral of force over distance).
Years ago, I remember reading about supercapacitor electrodes made from what would be waste hemp bast fiber. They used graphene as a control. And IIRC, the natural branching structure in hemp (the strongest natural fiber) was considered ideal for an electrode.
"Hemp Carbon Makes Supercapacitors Superfast" https://www.asme.org/topics-resources/content/hemp-carbon-ma...
How do the costs and performance compare? Graphene, hemp, durian, jackfruit
While graphene production costs have fallen due to lots of recent research, IIUC all graphene production is hazardous due to graphene's ability to cross the lungs and the blood-brain barrier?