Aerogel from fruit biowaste produces ultracapacitors(sciencedirect.com)
sciencedirect.com
Aerogel from fruit biowaste produces ultracapacitors
https://www.sciencedirect.com/science/article/pii/S2352152X19309077
7 comments
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!
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!
Hemp textiles are rough, but antimicrobial/antibacterial: hemp textiles resist growth of pneumonia and staph.
AFAIU, when they blend hemp with e.g. rayon it's good enough for underwear, sheets, scrubs.
The government is getting the heck out of the way of hemp, a great rotation crop that can be used for soul remediation.
AFAIU, when they blend hemp with e.g. rayon it's good enough for underwear, sheets, scrubs.
The government is getting the heck out of the way of hemp, a great rotation crop that can be used for soul remediation.
> soul remediation.
That's the best pun - or typo - that I've seen in a while.
That's the best pun - or typo - that I've seen in a while.
Maybe a freudian slip
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.
damn if hemp doesn't make a come back.. from cbd to ultracaps..
Hopefully but it’s only been legal to grow hemp in the US since 2018. https://www.vox.com/the-goods/2018/12/13/18139678/cbd-indust...
Technically, the 2013 farm bill (signed into law in 2014) authorized growing hemp for state-registered research purposes. https://www.votehemp.com/laws-and-legislation/federal-legisl...
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.
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.
An article that sums up the idea:
https://www.popularmechanics.com/technology/design/a31114696...
How does the storage capacity of these biowaste supercapicitors compare to that of a synthesized or inorganic material?
Is the Jackfruit and Durian selected because its spongy properties after being autoclaved?
Is the Jackfruit and Durian selected because its spongy properties after being autoclaved?
Title sounds like it was created by an HN article generator.
HN Mad Titles, now you can play at home!
___tech_thing___ FROM ___mundane_trash___ PRODUCES ___space_magic_thing___!
___tech_thing___ FROM ___mundane_trash___ PRODUCES ___space_magic_thing___!
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.
General capacitor question
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.
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)
If you hold the charge constant and capacitance goes down, voltage will go up (U = QC). The energy is (E = U^2C/2), so yes the energy will increase.
That extra energy is coming from your mechanic effort of separating two plates that attract each other.
That extra energy is coming from your mechanic effort of separating two plates that attract each other.
Ok wow that makes sense. So I’d actually have a hard time pulling them apart?
What’s the limit? What happens 1 meter apart? 20 meters?
What’s the limit? What happens 1 meter apart? 20 meters?
Much shorter distances can be useful: https://en.wikipedia.org/wiki/Microphone#Condenser_microphon...
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).
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).
The practical limit is not having electrons flying off due to the photoelectric effect or discharging due to conductive material in the environment.
So do it in a vacuum, in complete darkness.
So do it in a vacuum, in complete darkness.
I'd like to see aerogel batteries one day.
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?