Blakut

Blakut t1_jec05ho wrote

what's in renewable? Does it include gas? nvm, found:

Overall generation from conventional energy sources totalled 272.9 TWh in 2022 (-5.7% compared to 2021). However, generation from natural gas was 1.7% higher than in 2021, generation from lignite increased by 5.4% and generation from hard coal increased by 21.4%. This is due to the fact that Germany allowed coal-fired power plants to return to the electricity market to be less dependent on natural gas amid strained relations with Russia. Nuclear generation declined by 49.8% in 2022.

−3

Blakut t1_jdpy8xc wrote

> Convolutional networks are simply fully connected a

uhm no.

https://en.wikipedia.org/wiki/Convolutional_neural_network

Convolutional networks were inspired by biological processes[10][11][12][13] in that the connectivity pattern between neurons resembles the organization of the animal visual cortex. Individual cortical neurons respond to stimuli only in a restricted region of the visual field known as the receptive field. The receptive fields of different neurons partially overlap such that they cover the entire visual field.

2

Blakut t1_jdo76jp wrote

yes, but it's not the right or left eye, it's the left or right side of each eye. So if you cover the left side of both eyes or the right side of both eyes, you isolate one hemisphere or the other.

3

Blakut t1_jbdz7yj wrote

I expect a human to stop when I flinch and I'm in pain. I don't expect a robot to do that. At least not until I see thousands of operations done automatically with no victims.

1

Blakut t1_jars76x wrote

no they are not, i was thinking of something completely different. The stuff i work with, astrohysical sources, usually have two kinds of spectra: continuum which can come from a few things, such as free free emission, synchrotron emission, thermal emission from dust, and spectral line emission. The thermal part of the spectrum is usually very close to the ideal black body and deviations happen moslty because of geometry of particles (such as dust) and other stuff along the way, so i can separate the continuum from the spectral part. This of course gave me the wrong impression that most objects (also on earth) must have a spectrum close to a black body, and deviate from that only slightly because of things "around" the emitting body, such as gases absorbing/emitting, without considering that of course, Kirchoffs law applies to solids and everyday objects too (i only studied this in relation to gasses and some line emission scenarios).

1

Blakut t1_jarouro wrote

But the planck spectrum uses quantum physics... It cannot be explained classically.

edit: idk why i considered gases (which i thought i know) and solids (which i know i don't know) as so different. Kirchoffs law applies to solids too, so if a solid is a poor absorber at a wavelength, it must be a good emitter.

1

Blakut t1_jarmjpp wrote

>Electron gets excited, likely through atom/atom collision, either through literal collision in a gas or vibrations in a solid.
>
>Electron comes back down and emits a photon

You can have thermal emission only from point charged particle, you don't need electron levels, no? I don't have experience with solids, but this was my understanding, that it is proportional to the distirbution of velocities of atoms in the object, much like the free-free emission is a continuous spectrum too. I understand that different objects have different emissivities, and that emission at different wavelengths is different, but why would that be the case outside electron transitions? Could a possible crystalline lattice play an effect in this, restricting movements of individual atoms?

1

Blakut t1_jarimk4 wrote

The problem is the wiki article alludes that this line emission from atoms breaking off from the material and having chemical reactions in the flames around it is not entirely responsible for enhancing its glow.

edit: idk why i considered gases (which i thought i know) and solids (which i know i don't know) as so different. Kirchoffs law applies to solids too, so if a solid is a poor absorber at a wavelength, it must be a good emitter.

1

Blakut t1_jarhvo7 wrote

>A true perfect blackbody emits EVERY energy of photon along the curve, real matter in our universe can only do it at discrete energy levels on the curve

The energy levels of individual atoms have little to do with black body emission, no? You mean to tell me that the black body spectrum of real objects is choppy? Isn't the planck spectrum the result of taking into consideration the quantum nature of light, i.e. as discrete oscillators? Can you please give me a link where these steps arising from thermal velocities are observed and their mathematical description please? Also, keep in mind we are talking about solids here, not gases or plasmas.

The problem is the wiki article alludes that line emission from atoms breaking off from the material and having chemical reactions in the flames around it is not entirely responsible for enhancing its glow.

1

Blakut t1_jargfol wrote

Nevermind, found the correct answer: glow is due to oxides and chemical reactions AROUND the solid block of metal. However, the wiki article lists this effect as distinct from the black body spectrum of the object, and leaves the impression that even without it, the solid metal would glow more than a black body at those temperatures.

"Candoluminescence is the light given off by certain materials at elevated temperatures (usually when exposed to a flame) that has an intensity at some wavelengths which can, through chemical action in flames, be higher than the blackbody emission expected from incandescence at the same temperature.[1] The phenomenon is notable in certain transition-metal and rare-earth oxide materials (ceramics) such as zinc oxide, cerium(IV) oxide and thorium dioxide."

Whereas the wiki article for thorium says:

"A mantle glows brightly in the visible spectrum while emitting little infrared radiation. The rare-earth oxides (cerium) and actinide (thorium) in the mantle have a low emissivity in the infrared (in comparison with an ideal black body) but have high emissivity in the visible spectrum. **There is also some evidence** that the emission is enhanced by candoluminescence, the emission of light from the combustion products before they reach thermal equilibrium."

6

Blakut t1_jarffae wrote

No it's not combustion without oxygen. Spectral line emission usually originates from diffuse gases and plasmas, which exist also in flames, i.e. combustion, but not from solids. It is in the gas form that an atom can be excited, and then deexcite by emission of a photon, with little collisions happening while in the excited state. A solid block of metal (or other material) has a continuous spectrum, resulting from the velocity distribution of atoms in its composition, which usually resembles the Planck profile. Gases (plasmas!) also have a continuous spectrum, but that's a different story. If it was like the other poster said, a hot rod made of copper would glow blue when heated, while in reality the glow color depends on temperature of the rod.

Why does a solid block of thorium, when heated, emit more in the visible spectrum than in the infrared when compared to a black body of the same temperature? Is this claim even accurate?

Nevermind, found the correct answer: glow is due to oxides and chemical reactions AROUND the solid block of metal. However, the wiki article lists this effect as distinct from the black body spectrum of the object, and leaves the impression that even without it, the solid metal would glow more than a black body at those temperatures.
"Candoluminescence is the light given off by certain materials at elevated temperatures (usually when exposed to a flame) that has an intensity at some wavelengths which can, through chemical action in flames, be higher than the blackbody emission expected from incandescence at the same temperature.[1] The phenomenon is notable in certain transition-metal and rare-earth oxide materials (ceramics) such as zinc oxide, cerium(IV) oxide and thorium dioxide."

4

Blakut t1_jaraqch wrote

I don't think so, there is no burning involved. I don't think this is line emission, this is a solid incandescent piece of metal.
edit: why i said i don't think so is because the wiki mentions this effect as separate and distinct from the thermal emission of the solid.

−7