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Comment: Re:Perhaps it wouldn’t pass today’s .. (Score 3, Informative) 280

by nojayuk (#49076917) Attached to: 1950s Toy That Included Actual Uranium Ore Goes On Display At Museum

Raw uranium ores are a lot more radioactive than pure uranium oxides like yellowcake (U3O8) because of all the shorter-lived isotopes that have built up in the ore bodies from a billion years or so of decays of U-235 (700 million years) and U-238 (over 4 billion years). The other thing is that solid lumps of uranium are a good shield against radiation and the alpha particles resulting from decay events a millimetre or two under the surface are unlikely to escape the lump of metal and be dangerous.

Comment: Re:Great Job! (Score 1) 56

by nojayuk (#49042959) Attached to: ESA Complete Spaceplane Test Flight; IXV Safely Returns To Earth

Don't forget Japan which has delivered cargoes to the ISS using their home-grown launcher. They also launched a spacecraft, Hayabusa deep into the Solar system to rendezvous with a comet and return particle samples back to earth. The Hayabusa-II followup mission launched in December 2014 and it plans to return samples of an asteroid as well as landing three small hopping "rovers" on it for close-up study of the surface.

Comment: Re:Lasers are easy to stop (Score 1) 517

by nojayuk (#49006999) Attached to: The US Navy Wants More Railguns and Lasers, Less Gunpowder

How are they going to be guided? They're solid slugs of metal, they've just had ten million amps pumped through them and the equivalent of a short-range EMP imposed on any instrument package on-board and they're red hot from resistive losses. Just how do you intend to guide them to target 200 km away after all that? A large Acme-brand magnet from the Roadrunner cartoons perhaps?

Comment: Re:Lasers are easy to stop (Score 1) 517

by nojayuk (#48998755) Attached to: The US Navy Wants More Railguns and Lasers, Less Gunpowder

Unpowered unguided shellfire at extreme range is piss-awful inaccurate. Here's an image of the shot pattern from the Iowa BB's 15" guns; 25000 yards is only 14 miles, 36000 yards is about 20 miles.

http://www.fas.org/man/dod-101...

For this test the ship was sitting still, it wasn't travelling at 25 knots rolling in a heavy sea. In contrast a Tomahawk missile fired from a smaller cruiser or even a submarine from hundreds of miles away could hit an individual window in the Pentagon.

Unless railgun projectiles can be terminally guided like, say, aircraft-launched missiles then you can expect their fall of shot patterns to look like the Iowa's, only ten times wider since they'll have ten times as as long to deviate in flight over the extended range.

Comment: Radio coverage (Score 2) 248

by nojayuk (#48835341) Attached to: SpaceX Landing Attempt Video Released

The problem with blackout during a hot re-entry from orbit is plasma from the heatshield or tiles (in the case of the Shuttle) blocking radio signals at Mach 20 or so (about 6 km/second or thereabouts). This wasn't the case of the Falcon first stages as they were never going fast enough in the atmosphere to produce any plasma. If any of them had then the bottom of the stage would have melted since it's mostly lightweight low-melting-point alloys. Those sorts of temps would also have damaged a lot of the motors, the actuators, the guide fins etc.

As for the accuracy thing, again it was not a re-entry from orbit and the stage had guidance systems to bring it down to the barge, much as the Shuttle never had a problem finding the runway and painting the centreline during its landings. What puzzled me more was the speed at which the stage hit the barge. It should have been a lot slower, even with the failure of the guidance fins.

Comment: Re:Special non destructive test? (Score 5, Informative) 85

by nojayuk (#48782375) Attached to: The Mystery of Glenn Seaborg's Missing Plutonium: Solved

It's the other way around. Extra neutron captures in plutonium created in a nuclear power reactor produces Pu-241 and by decay, Am-241. The bombardment of U-238 with deuterons doesn't produce Pu-241. No Am-241 in the sample hence it was not produced in a reactor. That's the theory.

It's more complicated than that, there are ways of producing very pure Pu-239 in a reactor but the extreme purity of the sample in question seems to mitigate against it being produced by the capture of fission neutrons in a reactor.

Comment: Re:moot with 4k monitors (Score 1) 567

by nojayuk (#48577801) Attached to: The Case For Flipping Your Monitor From Landscape to Portrait

That's weird, I just read your "but 4k monitors aren't ready yet.." assertion on a 4k monitor...

I've got my old 1440p resolution display in portrait mode as a sidekick to my 4k monitor (a Dell PQ3214 bought in a Black Friday sale). I can throw edited page proofs etc. onto the portrait display while I work on the rest of the editing project and have browser windows, notes, a spreadsheet or two, image galleries etc. on my main screen.

I'm not sure I'd be happy running on just a portrait monitor and nothing else but as an adjunct to a decent-sized landscape display it works fine.

Comment: Re:Lots here... (Score 2) 67

by nojayuk (#48387955) Attached to: Boeing Readies For First Ever Conjoined Satellite Launch

The Ariane V has been launching two geosync large satellites simultaneously for quite some time but the upper satellite is carried on a frame/shield called SYLDA that fits around the lower satellite. Usually the two satellites being launched are different sizes and shapes. In this case it appears the Boeing satellites are roughly identical and docked together in their launch fairing saving on the weight and volume of the carrier. However the lower satellite has to cope with the mass of the upper satellite during launch. There is probably a strongback frame of some sort running through the lower satellite to handle that increased load.

Comment: Re:Not subject to Carnot efficiency limit (Score 1) 78

by nojayuk (#48327691) Attached to: Enzymes Make Electricity From Jet Fuel Without Ignition

Get back to us when they can make bombs, missiles, ammunition, spare parts and all the other things aircraft carriers consume on a day-to-day basis. Ditto for all the other fuel-burning ships in a carrier group. Until then you can expect a bunch of logistics ships and tankers to accompany the Big Boys wherever they go.

Where is this supermagical seawater-algae-avgas plant going to fit into the crowded spaces of an aircraft carrier anyway? Eating into the avgas tankage spaces might suffice but the US Navy really needs that volume filled with as much avgas as they can carry for an extended operational cycle. Carriers may be big but every cubic metre is already allocated to something, pretty much.

Comment: Re:This doesn't add up (Score 5, Insightful) 83

by nojayuk (#48087549) Attached to: Infected ATMs Give Away Millions of Dollars Without Credit Cards

Going back repeatedly isn't going to work -- the bank or financial company maintaining the ATMs does actually count the money going into the machines and the amounts legally withdrawn and if they don't balance then investigations are carried out. Put in 10000 quatloos, 7000 quatloos withdrawn by customers over a few days, 1000 quatloos left when the next refill is carried out = something fishy. Cookie jar accountancy rules apply, eventually Mom will notice the distinct lack of cookies and eventually catch you cookie-crumb-handed.

Comment: Re:Not going to be as rosy as the YES! campaign sa (Score 1) 494

by nojayuk (#47931187) Attached to: Scotland's Independence Vote Could Shake Up Industry

Both Hunterston and Torness, the two Scottish nuclear power stations will still be operational in 2020, producing about 2GW with an uptime of about 90%. The SNP, if they're in charge in an independent Scotland (and they're a one-note political party in the main, independence being their focus) want these reactors decommissioned and replaced with... they're not sure but no nukes! Gas-burning CCGTs, probably although the North Sea gas fields are not what they used to be so fuel will probably have to be imported after a decade or two. There are still a few coal-fired plants around and several wind farms, a couple of GW dataplate output but some days they only produce a few dozen MW in total. Solar is a non-starter in a country where the sun is in the sky for six hours in the winter and it's usually cloudy then anyway. Hydro, about a GW of capacity but it can't run 100% of the time, just when there's been enough rain recently. Sea-floor turbines are being trialled at the moment, no track record on costs per MWh generated, maintenance overheads etc.

Fossil fuel will provide a lot of Scotland's electricity for the forseeable future especially if the nuclear plants are not replaced when they are either shut down by government fiat or they reach the end of their licence periods and can't be relicenced.

A major English offshore wind project recently didn't go ahead even with a price guarantee of about UKP 145 per MWh, or in US consumer terms about 24c per kWh wholesale to the grid suppliers -- that would be about 30c/kWh to consumers after grid supply costs and profit figures were added, about what the Green Germans are paying and double the price of French nuclear-generated electricity at the wall-socket. I can't see Scottish wind power being any cheaper especially with the extra backstop gas generation and storage needed to keep the lights on when the wind stops blowing.

Comment: Re:Take the long view (Score 1) 494

by nojayuk (#47930175) Attached to: Scotland's Independence Vote Could Shake Up Industry

"if the referendum passes, what country will Sockatume be a citizen of? England or Scotland?"

No idea. It's one of the many things to be decided after the referendum and, presumably, independence in a years time or so if the vote is 50% + 1 for "yes".

"What passport will he have?"

No idea. See my previous response.

Independence means change, a lot of change over quite a short period of time. I expect a lot of handwaving and making shit up in a hurry about nationality, passports, currency, military affairs, border controls, representation in various supranational groups, embassies, tax offices, laws and judiciary, health and welfare, schooling, funding for assorted aspects of government, the whole nine yards. Usually independence is accomplished after a lot of bloodshed and burning when anything seems better than heads on pikes and clashing bands of armed marauders looting the countryside. Look at the mess the slaveholder's revolt in America in 1776 left in its wake after all.

Comment: Re:Take the long view (Score 1) 494

by nojayuk (#47928237) Attached to: Scotland's Independence Vote Could Shake Up Industry

As you say you had just accepted a job in England before the referendum was announced. I assume you moved to England and now live there, not in Scotland. It's your homeland but not your home any more.

Like you I'm born Scottish but I live in Scotland and I'll be voting in the referendum tomorrow. I rent my property from someone born and raised in Yorkshire, who went to Cambridge University but who moved to Scotland to live and work thirty years ago and they'll be voting tomorrow as well. Other people I know who have moved to Scotland from England will also be voting. I also know other folks like yourself that decided the high road to England and better-paid employment was for them and they're not getting to vote either because they don't live in Scotland any more.

Comment: Re:Why just guns? (Score 1) 264

by nojayuk (#47873241) Attached to: Using Wearable Tech To Track Gun Use

The open availability of firearms is a key factor in the US murder rate that is missing from other advanced Western nations which are not in a civil war or otherwise in turmoil. Murder rates for Sweden: 0.3, Australia: 1.1, Germany: 0.8, Switzerland: 0.6, Finland: 1.6, the US: 5.7. From Wikipedia, data from the past few years.

There's also the glorification of violence in US culture, TV and movies, the militarisation of the civilian population programmed to bend the knee to their uniformed overlords, a large ex-military segment of the population with mental problems, the War on Drugs and a lot of other things but firearms are up there as a major factor in the sore-thumb stakes.

I have hardly ever known a mathematician who was capable of reasoning. -- Plato

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