btrettel

77 ms·

871.
by btrettel 8y ago
I think slower flight might be best for long distance travel. Something like an airship. I don't know much about the technology, but my naive view is that the technology is undervalued. An airship has VTOL, is quieter, is more spacious
872.
by btrettel 8y ago
Fluid dynamicist here. I wasn't aware of the machine learning work you've mentioned. They're addressing an important problem, but I'm disappointed in the paper based on a brief look. I see no comparison against experimen
873.
by btrettel 8y ago
> I'm kind of curious about those models. Are there any major differences aside from the assumption of incompresssibility? I suppose they probably don't do equation splitting either? Other folks have already discussed differenc
874.
by btrettel 8y ago
Yes, "being careful" refers to a variety of different techniques, not just better software engineering. What has ended up being publishable in my case wasn't related to better software engineering, rather, being more careful
875.
by btrettel 8y ago
I think I misunderstood your position earlier. My experience with academic codes seems to differ significantly from yours. It is not uncommon at all for scientific software to have no documentation at all in my experience, and very little i
876.
by btrettel 8y ago
> you kind DO need that extra funding. because if you don't get funding for that you get out-competed [...] This seems to be a common view, but I don't think it's always true. In my own work, I've found that being car
877.
by btrettel 8y ago
I appreciate your thoughts. > I have actually written papers that try do to a bit of that and it was annoyingly hard to publish them. I don't know what field you work in, but in my field (fluid dynamics) these papers are not uncommo
878.
by btrettel 8y ago
The second link was fascinating and would make a good submission to HN. > Given my experience with those who write them, I tend not to trust most conjugational results coming from science. In computational fluid dynamics, there's a
879.
by btrettel 8y ago
These incentives exist but are not a good excuse in my view. I'd recommend reading this blog post about how "incentives" are used to justify all sorts of bad behavior in academia: http://www.talyarkoni.org/blo
880.
by btrettel 8y ago
Fluid dynamicist here. The $\beta$ notation appears to be a convenient way to write the Laplacian assuming that the temperature is homogeneous in the angular direction. The values are exact for certain coordinate systems. https:/&#x2F
881.
by btrettel 8y ago
Large smoldering fires contribute roughly 15% of total greenhouse gas emissions according to Dr. Guillermo Rein. http://guillermo-rein.blogspot.com/2016/06/erc-haze-reducing...
882.
by btrettel 8y ago
I'd push back if a public library refused to do ILL. (Though I can be fairly stubborn.) If cost is a concern, offer to pay. If a librarian says that they don't offer that service due to low demand, ask if they could make an except
883.
by btrettel 8y ago
Have you tried requesting a thesis or dissertation via a public library's interlibrary loan service? I am fairly confident that most universities would lend a thesis or dissertation to a public library. I don't see any clear reaso
884.
by btrettel 8y ago
I've used my (US) university's interlibrary loan (ILL) service many times. In my experience theses and dissertations are treated like any other book in interlibrary loan. Local public libraries also often have interlibrary loan, p
885.
by btrettel 8y ago
I live in Austin and I've made the exact same point to people before. Q: Which BBQ place should I go to in Austin? A: Most are good. I've even enjoyed the brisket served at the UT dining halls. (This is blasphemy to some.) You pro
886.
by btrettel 8y ago
Another pet peeve of mine is the absence of a discussion of why turbulence is a hard problem to solve. The reason is actually quite simple: the computational cost for directly solving the Navier-Stokes equations is far too high. They could
887.
by btrettel 8y ago
Fluid dynamicist here. This is a fairly nice video, though there are a few flaws. I was waiting for a derivation of the 5/3rds law, but it's not in the video. This is a shame as it can be derived very simply: http://mic
888.
by btrettel 8y ago
> Governments worldwide need to rush to figure out how to pay for roads when there is no gas tax revenue. Gas taxes pay for a fraction of new roads and road maintenance in the US. A large part comes from general taxation. I think it shou
889.
by btrettel 8y ago
You might be thinking of numerical error, which rarely dominates the full uncertainty if one is doing the computation right. You can quantify the full uncertainty in both scale/analogue models and numerical models. In my experience the
890.
by btrettel 8y ago
Fluid dynamicist here. If I were teaching this I would add the vorticity-streamfunction formulation before "primitive variable" incompressible Navier-Stokes in 2D. ("Primitive variables" include velocity and pressure, an
891.
by btrettel 8y ago
Looks like you can buy a variety of different styles here: https://equisafety.com/collections/polite
892.
by btrettel 8y ago
> Presumably this is in the hope of getting away with riding on the pavement or jumping red lights. Let's not jump to conclusions. Have you seen these folks break the law? The cyclists who wear hi-vis are much less likely break the
893.
by btrettel 8y ago
As a cyclist, I've worn a hi-vis vest while walking around after riding, and it's been weird how many people assume that I am a repair guy or even a police officer. The thesis of the article matches my experience. If you wear the
894.
by btrettel 8y ago
The Buckingham pi theorem typically doesn't tell you which scaling laws are valid, just how many of them there are consistent with the variables you believe are involved with the problem.
895.
by btrettel 8y ago
There's a great recent blog post on the basic point you're making: http://www.talyarkoni.org/blog/2018/10/02/no-its-not-the-inc...
896.
by btrettel 8y ago
I would cite the wiki with a note in the citation that the wiki was a copy of the 4chan thread. And I'd put a copy on an web archive service. WebCite was mentioned in the Twitter thread: http://www.webcitation.org/ If
897.
by btrettel 8y ago
I have filed both US and UK FIO requests. (But I am not a lawyer.) I think you are right in the UK. The US law is different and seems to allow this sort of broad request. I have been told before when filing in the US that others may request
898.
by btrettel 8y ago
I agree, but in this case stupidity can not explain their actions. The agency processing the FOIA request would get the export control status from the third party I contacted. The third party's software highlights export controlled doc
899.
by btrettel 8y ago
Also has a good example of hostile FOIA officers. I have filed about two dozen FOIA requests, and the vast majority were fine, though usually slow. Earlier this year one longstanding request of mine was rejected because they claimed the doc
900.
by btrettel 8y ago
Thanks, this was very informative and will change how I handle medical bills. Unrelated comment: I recognized your handle from some of your earlier posts where you said you're an independent researcher. I'd be interested in learni

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