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Comment: Structure & microstructure (Score 2) 43 43

I don't think the article is suggesting aircraft carriers have a big fabber below desks that will print you out a new aircraft. I expect it will be used in the first instance to reduce inventory for all the spare bits and pieces, and it will be asked to make a new handle for the coffee jug. But I reckon this could go a long way...

The big drop forges are used to form and work-harden material in one blow. If you have a press that is big enough to whack out a whole aircraft bulkhead in one go, then you end up with a thin, light component without any heat-affected zones from welds. That is pretty good way of making tough microstructures provided you can chose your atoms so they form the right sort of microstructures by themselves. You can, in theory have aluminium alloys with carbon fibres in them, but you cannot get them by conventional techniques. But you might be able to lay down sprayed metal and fibres and design your microstructure from scratch. It will probably be slow because you haven't got the massive parallelism of all the atoms doing the right thing for themselves, but it will get us into places that drop forging has never gone.

The other thing we can do is to make complicated internal structures. Our bones have a lattice of tiny struts that are continuously broken and repaired, which is how they optimise their strength. People have made a similar structure for a car bumper. It took a day to print a bumper but it had millions of little struts that absorbed energy as the bumper hit something and crumpled, in a way that a bulk plastic product never could. I can imagine aircraft wings could be stiffer and yet fail in a controlled slow bending rather than buckling if they were made like this. One day we could even mimic the regeneration process of our bones.

I suspect the actual story is nothing like as exciting as this. But it is a beginning.

Comment: iOS users feel it (Score 1, Insightful) 307 307

I currently have a web radio transceiver front panel application that works on Linux, Windows, MacOS, Android, Amazon Kindle Fire, under Chrome, Firefox, or Opera. No porting, no software installation. See for details of what I'm writing.

The one unsupported popular platform? iOS, because Safari doesn't have the function used to acquire the microphone in the web audio API (and perhaps doesn't have other parts of that API), and Apple insists on handicapping other browsers by forcing them to use Apple's rendering engine.

I don't have any answer other than "don't buy iOS until they fix it".

Comment: Re:plastic is for junk (Score 3, Insightful) 266 266

Have you ever had a LEGO brick turn squishy on you? Because that's what they're made of, ABS plastic.

It's a plenty tough enough material that I used it to manufacture parts for a geodesic dome for outdoor use as a greenhouse, and it held up fine. I also manufactured gears for a friends high end RC car after the manufacturer had gone out of business. Those gears see a lot of stress, and they held up fine.

ABS is a great material, and so is PLA.

Comment: Re:Randomness can't come from a computer program (Score 1) 64 64

Most of us do have a need to transmit messages privately. Do you not make any online purchases?

Yes, but those have to use public-key encryption. I am sure of my one-time-pad encryption because it's just exclusive-OR with the data, and I am sure that my diode noise is really random and there is no way for anyone else to predict or duplicate it. I can not extend the same degree of surety to public-key encryption. The software is complex, the math is hard to understand, and it all depends on the assumption that some algorithms are difficult to reverse - which might not be true.

Comment: (Score 4, Informative) 98 98

The original "Planetary Grand Tour" project would have visited Pluto, but it relied on a planetary alignment that would have to have started in 1976 or 1977. It was originally announced as a single craft, which became four before it was cancelled (I don't remember that, but for a brief history, see This was replaced by the two Voyager satellites launched in 1977. The later launch date made Pluto harder to visit, but it was still possible.

Comment: Re:Bad RNG will make your crypto predictable (Score 2) 64 64

The problem with FM static is that you could start receiving a station, and if you don't happen to realize you are now getting low-entropy data, that's a problem.

There are many well-characterized forms of electronic noise: thermal noise, shot noise, avalanche noise, flicker noise, all of these are easy to produce with parts that cost a few dollars.

Comment: Randomness can't come from a computer program (Score 2, Interesting) 64 64

True randomness comes from quantum mechanical phenomena. Linux /dev/random is chaotic, yes, enough to seed a software "R"NG. But we can do better and devices to do so are cheap these days.

I wouldn't trust anything but diode noise for randomness. If I had a need to transmit messages privately, I'd only trust a one-time pad.

Comment: Re:root problem (Score 2) 136 136

I reckoned you could do the equivalent with a superconducting cable around Mars' equator carrying about 500 amps. This sounds more do-able than it perhaps is, because the magnetic field has an enormous amount of energy so it would take years to establish the magnetic field; and all the energy would all come out if the cable is broken.

Comment: Re:I'm spending 60% of my monthly income on rent (Score 1) 939 939

Communism has been tried on a large scale - see Mao's Great Leap Forward.

Nope. That was a totalitarian socialist program pushing a collectivism that didn't work. Communism is a post-scarcity society and obviously scarcity was the thing Mao produced best.

Comment: Precautions against unknown disease (Score 1) 57 57

The same thing can happen with another new disease that they don't know about, which in turn means they aren't screening for.

That's why most places (at least around here) also screen for behaviours which could end with blood borne disease spreading.

i.e.: You can't immediately donate blood after having a tattoo done.
Even if you are HIV negative, there might be another unknown disease that could have spread from improperly cleaned tools.
Need to way some time (1 year) before starting giving blood again.
By that time you'll have started showing symptoms and/or news of a new blood borne disease will have been heard.

Comment: Re:What's the score now? (Score 1) 77 77

I didn't actually work on GPUs very much at Pixar, the image computer I worked on was the grandfather of the SIMD image processing instructions on modern CPUs. What would become a GPU later on was a very expensive box from Silicon Graphics, I had one that cost at least a quarter Million dollars.

"Even if you're on the right track, you'll get run over if you just sit there." -- Will Rogers