lambdatronics

10 ms·

61.
by lambdatronics 4y ago
I loved the grade-school math textbook series by Harold Jacobs: - Mathematics: A Human Endeavor - Elementary Algebra They are peppered with cartoons (especially B.C.) and have lots of real-world motivation. I definitely recommend them for
62.
by lambdatronics 4y ago
Yeah. This blog post [0] has a nice graph showing that at continued exponential growth of energy consumption, we have less than a few hundred years until the planet would become uninhabitable simply due to the amount of additional heat. In
63.
by lambdatronics 4y ago
Fuel cells convert chemical -> electrical directly, batteries go both ways. For nuclear fusion, the only practical reaction releases 80% of the energy as uncharged particles (neutrons), for which the only way to harness their energy is t
64.
by lambdatronics 4y ago
It's been considered, for a variety of heat sources. I'm long-term bullish on a related technology (thermophotovoltaics), although presently the efficiencies are not great & the compatibility with nuclear radiation is probably
65.
by lambdatronics 4y ago
Not the same kind of turbine. Internal combustion turbines are more cost-effective than steam turbines.
66.
by lambdatronics 4y ago
Depends on what kind of contribution you want to make & how much you want to learn, and what skills you already have. If you wanted to be on the cutting edge as a fusion physicist, and let's imagine you are a bit rusty on calculus
67.
by lambdatronics 4y ago
What I liked least about Jira was how it turned a project into a maze full of pages of boilerplate, all alike. I was continually walking the issue/subissue tree via hyperlinks, and the pages were slow to load, and sometimes I went in c
68.
by lambdatronics 4y ago
If we want the intelligence to be recognizably human-like, then yes. As to whether the AGI could be trained in a simulation vs needing to really be physically embodied: I used to believe not, but then I learned about sim2real. (Ex: [0]) Tra
69.
by lambdatronics 4y ago
That's a really profound question that deserves serious research, IMO. Communication is easy enough to define using Shannon's theory of information. I would argue that computation is subset of communication: signals go in one end
70.
Ask HN: What is your failed/cancelled project story?
39 points by lambdatronics 4y ago|12 comments
71.
NuScale Has Gone Public(nuscalepower.com)
20 points by lambdatronics 4y ago|1 comments
72.
by lambdatronics 4y ago
Wait until you find out about enstrophy.
73.
by lambdatronics 4y ago
> Isn't "order" a metaphysical concept Yes. The most scientific way of talking about "order" in that sense is the Kolmogorov complexity, which is still extremely poorly-defined. The best way to put it is that &qu
74.
by lambdatronics 4y ago
Yeah, you also have to transform the "reference" function, and then the entropy stays the same. I prefer to think of it as the "density of states" -- it's necessary to make the argument of the logarithm dimensionles
75.
by lambdatronics 4y ago
>how physicists get around the discrete and finite restriction By turning a sum into an integral. The probability 'density' is p(x), and the 'density of states' is n(x), so then entropy is then integral of p(x)log(p(x
76.
by lambdatronics 4y ago
>It seems to say that "given a system we know everything about, there is no way to go to a system that has some unknown things to us". That's backwards: information is the negative of entropy. The 2nd law says that entropy
77.
by lambdatronics 4y ago
>I don't know what Entropy is supposed to mean on the level of individual states/configurations. The entropy is a property of a probability distribution, not of a state. Entropy is defined as H = -sum(p_i log(p_i)). A 'sta
78.
by lambdatronics 4y ago
Is that just a coincidence for N=2?
79.
by lambdatronics 5y ago
There are a broad range of motivations. In my case: - I wanted to work on nuclear fusion energy, for the future of humanity. - I was told that if I had a PhD in physics, I could do just about anything - it's a way of keeping options op
80.
by lambdatronics 5y ago
Fusion researcher here. Yes, this piece is sensationalized, as are most pieces about fusion, and about science/technology in general, unfortunately. It's depressing that tokamak performance hasn't improved much in all that ti
81.
by lambdatronics 5y ago
CFS claims that it's manageable, although I don't know enough to evaluate that claim. It's also not clear from this quote if the once/twice per year is referring to full replacement of the vacuum vessel, or maybe just to
82.
by lambdatronics 5y ago
Interesting. I wonder if personification is analogous to a "memory palace": it's a way to hijack our innate brain capacity for working on something more abstract. I've always felt like physics derivations were like myste
83.
by lambdatronics 5y ago
I like having static analysis for undefined names in my IDE for exactly this reason: I can write the program in the natural order (high level to low level), and then have a little reminder about what I haven't finished yet.
84.
by lambdatronics 5y ago
Cool idea! I'm pretty busy a.t.m. but just in case, I'll toss my hat out there. About me: -PhD in physics, specialty in optical spectroscopy for fusion reactor plasmas -Familiar with basic optics, analog circuit design & fabri
85.
by lambdatronics 5y ago
The famous Alan Kay appearance: https://news.ycombinator.com/item?id=11939851
86.
by lambdatronics 5y ago
This one? https://news.ycombinator.com/item?id=24537865
87.
by lambdatronics 5y ago
What's your take on the idea of on-orbit propellant gathering?[0] That is, the concept of a solar-electric propulsion sat in low orbit 80-120km, scooping up atmosphere, ejecting the nitrogen to compensate drag while storing the oxygen
88.
by lambdatronics 5y ago
Cool stuff! I'm curious if you considered Julia when choosing the language to work in, & if so, what were the pro's/con's vs Go.
89.
by lambdatronics 5y ago
Great idea, I was wondering if someone had started working on something like this. My thought was to use the identity for distributed social media (blogging platform where you can easily restrict viewership of your posts by granting revocab
90.
by lambdatronics 5y ago
Thanks! What kind of problems outside academia are you interested in?

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