lambdatronics

6 ms·

1.
by lambdatronics 2y ago
Location: Seattle, WA, USA Remote: Yes Willing to relocate: Yes Technologies: Python, Matplotlib, Scipy, Numpy, sk-learn, Keras, Tensorflow, Julia, Fortran, SQL, git, slurm, Linux, MS Office, analog circuit design, optical systems design, h
2.
Astro Electronic(astro-electronic.de)
1 points by lambdatronics 2y ago|2 comments
3.
Coke can planimeter(durealeyes.com)
72 points by lambdatronics 2y ago|20 comments
4.
by lambdatronics 3y ago
>already a fairly radically super-human speech center >We're asking a speech center to do an awful lot of tasks that a speech center is just not able to do Exactly! >We need more parts. Yeah, imagine what happens once we get t
5.
by lambdatronics 3y ago
>a way to generalize the compute graph as a learnable parameter. Agreed. Seems analogous with how human mental processes are used to solve the kind of problems we'd like LLMs to solve (going beyond "language processing" wh
6.
by lambdatronics 3y ago
>What would it even mean for a particle to have an "action" (whatever that is) that is not minimized? The particle doesn't have an action. The trajectory of a particle is what the action is defined in terms of. One way t
7.
by lambdatronics 3y ago
Cool! I had been meaning to try my hand at a to-do app ever since I read "Getting Things Done" a few years ago, and I finally spent a couple weekends on it this month. The tree structure is 100% the way to go, and it's surpri
8.
by lambdatronics 3y ago
I see what you did there with the Dr. Horrible reference! :D
9.
by lambdatronics 3y ago
IIRC sodium ion batteries have traditionally had trouble with rapid degradation due to the large size of the sodium ion, which disrupts the carbon electrode via swelling during intercalation. So I would be worried about the number of cycles
10.
by lambdatronics 3y ago
Thanks stuart8ol for all the detailed answers in this thread. I learned several new things today (use of compressors for fuel cells to increase power density, logic of airplane sizes). This is the stuff I come to HN for! Also cool to see yo
11.
by lambdatronics 3y ago
> But the trade off should not be "if there is any risk at all, then no" I'm a kitesurfer and I'm with you 100%. I'm glad kiting is not banned in most places. Kiters die every year -- I knew someone who was kill
12.
by lambdatronics 3y ago
The paper says that this is only half of a solution: "Our investigation here has focussed [sic] on the fundamental Li-NRR performance at the cathode. Further developments towards a complete ammonia electrosynthesis system will requir
13.
by lambdatronics 3y ago
First you want to displace natural gas for fertilizer production. But yes, if the energy efficiency is good enough and the electrolyzer costs are very low, it would make more sense than electrolyzing hydrogen and then running that through H
14.
by lambdatronics 3y ago
Probably not just yet. I calculated downthread that the productivity is something like 16x less per unit area than a hydrogen electrolyzer, so that would need to be improved to make it cost-effective probably. Also they don't mention t
15.
by lambdatronics 3y ago
Probably refers to "Coulombic efficiency." Ie, it takes 4 electron transfers to turn 2 H2 + N -> NH4, so that gives you a conversion factor between Coulombs of electrons (1 Amp of current is 1 Coulomb per second) and number of
16.
by lambdatronics 3y ago
For hydrogen electrolysis they typically quote around 1 A/cm^2 current. One Coulomb is ~6e18 charges, whereas one mole is 6e23 molecules, so that makes about 1e-5 H atoms per cm per second. Of course making one molecule of ammonia nee
17.
by lambdatronics 3y ago
Only if there's enough wind shear between the aircraft and kite altitudes... kinda like dynamic soaring [0] but without the need for the aircraft to jump back and forth between the two regions. You'd probably need to use a sailpla
18.
by lambdatronics 3y ago
No-moving-parts is probably not realistic - the core would be much hotter than the radiating surface due to the thermal resistance of the shielding. More likely, you would have a working fluid to transfer the heat. Most nuclear reactors ope
19.
by lambdatronics 3y ago
Yeah, tungsten is far too expensive. Sounds like more realistically you would have molten silicon in graphite plumbing [0]. This article claims the self-discharge rate could be made 1%/day. There's been talk of doing solar concent
20.
by lambdatronics 3y ago
Just to amplify on your point about lithium: the tritium production function is critical. Every fusion neutron needs to produce more than one tritium atom on average, so that the reactor is sustainable (there are inevitable losses & tri
21.
by lambdatronics 3y ago
Not at the moment. IMO the prospects aren't good, due to the low efficiency (high energy cost) and high equipment cost. There are start-ups working on it (ex: Prometheus Fuels [0], Twelve [1], Synhelion [2], honorable mention to Terraf
22.
by lambdatronics 3y ago
"Information theory and statistical mechanics" by E.T. Jaynes [0]. Starting from a Bayesian/information-theoretic perspective, he derived statistical mechanics in just a few pages. This approach finally made stat-mech 'c
23.
by lambdatronics 3y ago
ReBCO still isn't practical for grid transmission AFAIK. It needs to be cooled to something like 20 K to achieve high current. That's ~4x warmer than traditional superconductors (~4.5 K) but it's still not "high temperat
24.
by lambdatronics 3y ago
ReBCO is a huge boon for magnetic-confinement fusion. The comment from their CEO that "In fact, from a physicist’s standpoint, our machines look kind of boring [...] we could get extremely high performance through the brute force of th
25.
by lambdatronics 3y ago
I toured a multi-million-dollar electron microscope at ORNL. They had a piece of tissue paper taped to the side. I asked about it, and they said that it was an airflow monitor. It turned out to be more sensitive than some very expensive sen
26.
by lambdatronics 3y ago
That's a great way to put it. ("properly functioning state of consciousness") Because some folks would argue that the it isn't functioning. That brings us to the question of "What does it mean to be properly functio
27.
by lambdatronics 3y ago
I've worked on two different plasma devices where the engineers used a different coordinate system from the scientists.
28.
by lambdatronics 3y ago
>But points of sail don't have any handedness, correct? I.e. they're mirrored on both sides of the wind. The right-of-way rules in sailboat racing depend on who is on 'port tack' or 'starboard tack' (ie, the
29.
by lambdatronics 4y ago
>To think deeply about meta science in any official capacity as part of PhD training requires you to go out of your way. Yup. Not just life sciences, this applies to physics as well. >I also imagine that even in less expensive/sl
30.
by lambdatronics 4y ago
I wouldn't say it is useless. But, there's an extent to which "I can explain it to you, but I can't understand it to you." There's an interesting school of thought saying that in order to understand an idea,

More ›