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Comment: Re:Competing with government-sanctioned monopolies (Score 1) 184

the utility power is a "natural monopoly" and how, therefor, it can not be subject to competition...

I would take a more nuanced approach to it. It's not that it cannot be subject to competition, it's more that it is unreasonable to expect competition to magically appear - as one would expect in other markets - due to the impracticalities (i.e., having two sets of power lines) and the high cost to entry.

Comment: Re:UV sensitivity (Score 2) 95

I take it you've never worked with SLA resins and parts then. Mass-produced plastic parts have varying degradation rates in the sun. Many have UV stabilizers in them that provide them with substantial life (many years) even in direct sunshine. SLA parts, in my experience, have a useful life measured in weeks if allowed to be in the sun. Even sitting around in an office environment, SLA parts will degrade over months.

Comment: Re:projecting UV images from below liquid resin? (Score 1) 95

So I wonder how this UV projector doesn't cause solids to form inside the vat if in fact this projector can cause plastic to solidify as it is being removed from the vat with liquid resin.

Or you could read the article to find out the answers to your questions.

Comment: Re:Wasteful? (Score 1) 95

by necro81 (#49161147) Attached to: Ikea Unveils Furniture That Charges Your Smartphone Wirelessly
Well, to quote the summary: "Ikea's introduction of wireless charging functionality on some of its new furniture heats up the battle for a global wireless charging standard"

Although you can get up into the 80% range (short distance between emitter and receiver, good axial alignment, well-tuned resonance frequencies, and proper shielding), you are more likely to be in the 50-75% efficiency range. That's for the inductive portion; there is also a loss in converting the 120/220V power from the wall. [I speak from professional experience developing a Qi-charged medical device. It was a good solution for the problem, as it allowed the case to be fully sealed, but turned me off the idea of using it for everything that needs charging.] For 5-10 W of actual charge power in the device, your losses from grid to device will be close to that amount This is about as bad as the 50-60 Hz wall wart transformers that we have recently gotten away from.

Comment: Re:is it an engine or a display model? (Score 3, Informative) 58

by necro81 (#49149537) Attached to: Researchers Create World's First 3D-Printed Jet Engines
3D-printed metal has been used for quite a while in some of the lower-performance stages (lower pressure, lower temperature). Examples here. The key benefit is that they are able to integrate convoluted channels within the structure for cooling or mixing. You can also reduce weight by taking away significant internal volume, replacing it with ribs or a sparse matrix. I wouldn't go so far as to say that it's mainstream, but it's close.

Comment: Re:Russian steep price (Score 2) 106

by necro81 (#49103157) Attached to: ISS Crew Install Cables For 2017 Arrival of Commercial Capsules

Russia is doing all the taxi work — for a steep price

How much is it more expensive than private industry?

"Price" in this case may be an imprecise word. The monetary cost may not be all that bad compared to SpaceX or Boeing. (It may even be favorable, for all I know.) However, it does carry serious risk to have only one supplier that can get you to the ISS. Sometimes the public and private sector properly take the (potential) costs of risk into account. This is what the insurance industry does - putting a monetary cost (price) on risk. Other times people get blindsided by something that, in retrospect, they couldn't afford. Sometimes the risk is not quantifiable - can you put a price on the strategic risk of Russia getting one over on NASA (and, by extension, the USA)?

In other words: risk can be very, very expensive, whether it is included in a pricetag or not.

Comment: Re:gloop (Score 4, Informative) 68

by necro81 (#49049979) Attached to: Cosmic Rays To Reveal the Melted Nuclear Fuel In Fukushima's Reactors
The industry term for the mixed, melted contents of a reactor core is "corium". It's a mix of fuel rod assemblies ( fuel and fission products, additives, moderators, salts, and cladding), fuel rods (zirconium), and containment vessel (stainless steel), all compounded with reactor water and whatever additives were in it. In a theoretical worst case, you get to add in some concrete from the floor of the reactor building, too.

In short, about half the periodic table.

Comment: Re:I'm thinking there's a bigger problem... (Score 2) 119

by necro81 (#49029939) Attached to: NASA Releases Details of Titan Submarine Concept
In the article, their plan is have a large dorsal fin (the thing that looks like a vertically-oriented solar array in the artist's concept) which would be a phased array for direct transmission to Earth. To quote:

However, the direct transmission of worthwhile amounts of data over a billion miles to Earth requires a large antenna, implemented as a planar phased - array dorsal fin. (It was decided to simplify the mission to exclude a relay orbiter which would require significant propulsion and radioisotope power.) This antenna structure introduces a modest submerged drag penalty, as well as demanding judicious placement of large tanks for adequate buoyancy margin and surfaced stability.

Comment: Re:steam rocket (Score 1) 119

by necro81 (#49029791) Attached to: NASA Releases Details of Titan Submarine Concept
I wondered about this as well: if you can create a gaseous or mixed-phase layer around the sub, you ought to be able to move through the liquid with reduced drag. You can't do this on Earth with something the size of a manned submersible - the necessary thermal flux would be insane - but I'm sure someone could make a PhD thesis out of modeling, then experimenting, with this in cryogenic liquids.

Comment: Re:I'm thinking there's a bigger problem... (Score 1) 119

by necro81 (#49029687) Attached to: NASA Releases Details of Titan Submarine Concept
Damn, I just knew those NASA engineers were forgetting something!

Probably they would do it in a manner similar to how they do it with conventional submarines: occasionally surfacing and transmitting normally, or else releasing a buoy with communications capabilities.

Comment: Re:Consider the denominator (Score 2) 136

by necro81 (#49020825) Attached to: DEA Hands MuckRock a $1.4 Million Estimate For Responsive Documents

Swagging it, 1.4 million implies at least 14 staff attorneys would have to work 12 months

At the least, I'd like to see a breakout of the labor estimates. It seems double to quadruple what I would expect.

You think the going rate for a staff attorney is $50/hour ($1.4mil, 14 persons, 2000 hrs/12 mo)? You haven't been around many attorneys, have you? The salary may work out to that (about $100k/yr), but with benefits and overhead, it could easily be double that. Just be lucky that an outside firm doesn't need to be involved - considering DC's rates, it could easily work out to $300/hr.

Comment: Re:Why let it crash? (Score 3, Informative) 23

by necro81 (#48930781) Attached to: The Big Bang By Balloon
Another Antarctic balloon experiment, BLAST, was designed for re-usability. On its third flight, the parachute failed to properly detach, and ended up dragging the telescope for more than 100 miles across the ice, mostly destroying it.

This doesn't mean that one shouldn't try to recover and reuse experiments, but it does present new program-level risks.

The answer as to "why don't they?" could be as prosaic as: they didn't get funding for a multi-year, multi-launch program, or couldn't squeeze the reusability and refurbishment into their program budget.

(For those interested, that third mission was the subject of a neat documentary film.)

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