Arne Dehli Halvorsen

Software Architect.
@[email protected]

[Arne Dehli Halvorsen @arne_d_h]

@anineki Like svakt som at siste dagers begivenheter ikke har ført til overskriften "Jukselapp?"

[Papa Woof und Krampus und Bleaken @woofknight]

Busy, cold night at Stonehenge as we move the stones backwards an hour...

[Fake History Hunter @fakehistoryhunt]

😁

[Michael Hartl @mhartl]

I feel like this may prove to be the most prescient cartoon of the 21st century.

[Douglas Cheape @CheapeDouglas]

A wee wummin on the Maxwell Park to Glasgow Central train just sighed and said to her pal that something was ‘all part of life’s rich travesty’, and after the week I’ve had I see no reason to correct her (not that I would anyway).

[Arne Dehli Halvorsen @arne_d_h]

@KriLoseth @eivindtraedal Luksus. Vi loddet kretsene selv og rørte dem borti hverandre i tordenvær. Greide to bits lagring, men hadde paritetsfeil

[Jesse Peltan @JessePeltan]

Photovoltaics are by far the coolest energy tech.

We turn the most abundant elements in Earth's crust into devices that exploit quantum mechanics to harness the power of stellar fusion and convert it into a perfectly ordered form of energy - electricity. Pure exergy under human control.

People know Einstein for E=mc^2 and relativity, but Einstein won the Nobel Prize "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect"

Einstein explained the photoelectric effect using light quanta - photons. The discovery of the quantum nature of light was a pivotal moment in the development of quantum mechanics.

The explanation of the photoelectric effect wasn't Nobel prize winning because of its potential for electricity generation, it was groundbreaking because it showed that the quantum nature of light wasn't just a math trick but an accurate description of physical reality.

Solar cells use the photovoltaic effect (the cousin of the photoelectric effect), exploiting the quantum nature of light to drive an electric current rather than eject electrons from a material. Photovoltaics aren't just quantum tech, they exploit a phenomenon central to our very understanding of quantum mechanics.

The Sun is the source of exergy that drives motion, change, and life on Earth. Everything else (geothermal heat, nuclear decay, tidal forces, etc.) is a rounding error.

Photovoltaics allow us to directly and efficiently harness that exergy to shape and drive change in the world.

We literally could not build a better fusion reactor if we tried. The Sun is 330,000 times the mass of the Earth. It can fuse protium, not just D-T fusion like we do on Earth. Half a million kilometers of shielding convert MeV level neutrons into thermal energy in a spectrum that just touches the limits of the strength of chemical bonds.

Our atmosphere provides additional shielding from high energy UV photons, leaving us with radiation primarily in the 1-3 eV range - perfect for the photoelectric effect.

High energy UV photons can break apart the bonds between atoms. Ultra high energy neutrons and gamma rays can break apart atoms themselves. Nuclear reactors have to first convert the energy in high energy particles into a lower grade of heat that materials can handle before we can harness useful energy with a heat engine. The Sun and our atmosphere do that for us.

The maximum efficiency of a heat engine is limited by its hot and cold side temperatures.

Gravitational confinement and 150 million kilometers of vacuum insulation let us have the hot side of our heat engine (the Sun) at 5800 Kelvin. There is no material that can withstand temperatures anywhere close to that. 5800 K vaporizes tungsten. Hafnium carbide melts at 4200 K.

Single junction solar cells are limited to about 33% efficiency with an ideal band gap of 1.34 eV. Silicon at 1.1 eV could theoretically reach 32%, and the best silicon cells today top out around 27%.

By using multiple junctions, or by using photon upconversion and downconversion, solar cells could reach thermal efficiencies that aren't even theoretically possible with conventional heat engines due to materials limitations. (without some kind of contactless confinement like we get with the Earth/Sun system)

Current multi-junction solar cells are not as efficient as our best heat engines, but there's nothing thermodynamically limiting photovoltaics from surpassing the thermal efficiency of conventional heat engines.

We may not be able to turn lead into gold, but we can exploit quantum mechanics to turn sunlight into electricity. That's more magical than anything any alchemist could have ever dreamed of.

[Arne Dehli Halvorsen @arne_d_h]

@ConspiracyBull1 if raisins come from grapes, how come there are still grapes, huh?

[John Pavlovitz Official @johnpavlovitz]

No one on the Left I know wants Donald Trump injured or dead.

We want him to lose the election and pay legally for his myriad of crimes against this nation and its people.

[Knut Falk Qvigstad @KnutQvigstad]

Nei, slike brutale flatehogster er ikke god naturforvaltning. Det lokale økosystemet avvikles. Man inviterer til erosjon. Jordsmonnet utarmes. Naturlige karbonlagre tømmes. Norge trenger en ny skogbrukspolitikk!

[Arne Dehli Halvorsen @arne_d_h]

@skribente Legge tak over hele USA - tror du han kan få tak amerikanskfødte offisielle taktekkere?

[Arne Dehli Halvorsen @arne_d_h]

@tophepahle "Da uttales det tydeligvis som en type stemmebruk", sa han hést

[Moose Allain Ꙭ @MooseAllain]

The 'Three Little Pigs' story harks back to a time when wolves roamed Britain and pigs drove innovation in the residential construction sector.

[The Onion @TheOnion]

Study: Crows Intelligent Enough To Steal Trinkets, But Foolish Enough To Think Material Goods Will Solve Problems https://t.co/ecWRmOCWS5

[Arne Dehli Halvorsen @arne_d_h]

@KriLoseth 3. Den blir( nesten) helt umulig å avslutte

[Arne Dehli Halvorsen @arne_d_h]

@HyggeligTjommi Vosselukta