Every time I consider LASIK or other procedures that would remove my need for glasses, I recall that in 23 years, my obligate glasses have saved each eye once. Two dead center strikes from disintegrating server cooling fan blades. I'd have lost both eyes.
Readit Newsridgeguy commented on Electromechanical reshaping, an alternative to laser eye surgery medicalxpress.com/news/20... · Posted by u/Gaishan
Cool results and methods, but I'll disagree with one of the article's statements.
In talking about the work done on e. coli, a non spherical cell, it says the methods had to be changed due to "turbulence" attendant to the e. coli's departure from sphericity of the earlier tested yeast cells.
My rough calcs show a Reynolds number in the range of 1e-6. The onset of turbulence happens at Reynolds numbers of ~2300 for pure water. The 1% sugar solution would have a negligibly higher turbulence onset Reynolds number.
I expect the need for different methodology wasn't turbulence, but the difference in drag presented by an elongated e. coli compared to a spherical yeast cell.
ridgeguy commented on US Coast Guard Report on Titan Submersible news.uscg.mil/Press-Relea... · Posted by u/rwmj
Fiber-reinforced composites are basically analogous to spaghetti dispersed in glue. Really strong in tension, when the (in this case, carbon) fibers are taking nearly all of the load. In compression, the fibers have nearly zero resistance to flexure, and the load is mainly being taken up by the glue (the matrix, in composite-speak). When the fiber/matrix interface fails due to fiber flex-induced shear force, you're done.
I just can't imagine why a submersible structural designer would select composites for this application. IMHO, this project was doomed from the moment of that design decision, even setting aside all the other idiocy.
I'm building a CVD system to make arbitrarily large single crystal optical quality diamonds. Not a coder, so I'm using ChatGPT and Claude to show me how to integrate microwave power sources, vacuum & gas supply systems, and other subsystems with LabView. As Gust said in Charlie Wilson's War, "We'll see.".
The difference is instantly apparent under UV - most lab grown diamonds will not fluoresce unless they have a bad growth process that leaves flux and other impurities in the crystal.
Natural diamonds won't always fluoresce but the ones that do will do so in a variety of colors, and sometimes change depending on what wavelength is irradiating them.
Lab-grown diamonds can be tailored to exhibit the same impurities internal stresses, etc. that cause a minority of natural diamonds to fluoresce. This has not been a goal to date for synthetics because the highest price point is for diamonds that are most pure with least internal strain. If the economics of fluorescent diamonds suddenly become more attractive, I guarantee fluorescent synthetics will be on the market immediately thereafter, and will be indistinguishable from naturals without $100K worth of characterization tools.
Two points just FYI in thinking about the sudden shift to synthetic diamonds from natural stones:
• Scale: I'm aware of one company that operates over 700 CVD systems that each make 25 stones/run - there are at least 3 others of similar volume;
• Cost: the variable cost of making a 1ct finished brilliant (D-E,F-VVSI) is <$30US. Obviously, that cost is for ex-US production. See, for example, the recent demise of de Beers' Lightbox growth center in Oregon.
Naturals simply can't compete. They are forming a completely separate market involving a much smaller, extremely wealthy clientele.
The business case for synthetics is deteriorating as production costs bottom out and margins decline in an ongoing race to the bottom.
ridgeguy commented on A technical look at Iran's internet shutdowns zola.ink/blog/posts/a-tec... · Posted by u/znano
Am I right to assume that it's easy to locate the source of ham radio signals?
i.e. if there's a blanket ban, can you use your radio hidden in your house or can the government easily find out that the user they've noticed on the airwaves is located there and knock down your door?
It's very easy, has been for a long time. See the story of Israeli Eli Cohen, an operative in Syria.
I'm working on making diamond single crystal rods as long as you like. For lasers and the like.
ridgeguy commented on Iron nitride permanent magnets made with DIY ball mill [video] youtube.com/watch?v=M6XIg... · Posted by u/xqcgrek2
> ammonium nitrate is by todays standards just one step up from black powder
I thought that was potassium nitrate. Which I bought a bottle of on Amazon when I was curing a ham.
Didn't know about the use for meat curing. I've routinely bought KNO3 for stump removal.
ridgeguy commented on The Polymarket users betting on when Jesus will return ericneyman.wordpress.com/... · Posted by u/surprisetalk
Purpose. That there was a purpose for all of this. If we believe there was no purpose for all of this, then what a hopeless thing. I just look at the erasure of Gaza and have become more and more religious, because my god what a hopeless end if this all isn’t saved at the very end. I feel that way about many of today’s ills.
Purpose and hope, even if the answer is utterly magical.
Opposite to my view. If there's no pre-ordained purpose, we're free to invent our own. I find that very freeing and hopeful. And a lifetime project.