* Posts by Robert Sneddon

332 posts • joined 14 Dec 2007

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Slower US F-35A purchases piles $27bn onto total fighter jet bill

Robert Sneddon

Acoustic generators

The propulsion system for the QE carriers runs to about 50MW of electrical power. To mask the noise of the propellors with "acoustic generators" would require a similar amount of power (as well as a ginormous bill from Richer Sounds for the speakers). The two main gas turbine generators on these ships put out 70MW at full chat and there's some extra backup diesel units to add another 30MW or so. I don't know where the extra power for these "acoustic generators" is going to come from. Big wind turbines on the flight deck perhaps?

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Robert Sneddon

Satellites don't work with clouds.

That's why the Russians and the Americans operate radar ocean observation satellites, looking down through the clouds and in darkness to find and track big surface ships like carriers.

As for getting an acoustic signature from the QE carrier's propulsion system the Russians are going to get one sooner or later even with watchdog escorts, now or in three months time or when it goes operational in open waters. I expect the Russians to be flying TU-95 Bears as close as they can to give themselves some idea of the radar profile of the newest target for their KH-31 and similar air-launched ship-killer missiles too.

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Robert Sneddon

Re: Sea Gripen

Is there a short-takeoff version of the Gripen that can get off a short strip under its own power (zero to wheels-up in fifty metres or so fully loaded in adverse sea conditions?) If not then it's not gonna fly off the QE carriers since they don't have catapults of any kind.

The QE carriers don't have classic steam catapults because they don't have big steam boilers like the previous generation of carriers, they use gas turbine generating plants and electric motor drive because that's how modern non-nuclear warships work these days. Adding a steam catapult system would necessitate building steam boilers and desalination systems into a hull that's already full of planes, power plant, fuel stores, weapons stores etc. Each steam catapult "shot" takes half a tonne of fresh water or so, to give you an idea of what's needed.

The new Ford-class US nuclear-powered carriers don't have steam plant either, they're electric motor drive too. They're using an electromagnetic catapult system to launch aircraft but they've got a lot of spare electrical generating capacity for just this reason, two 300MWe nuclear reactors (their predecessors got by with two 150MWe reactors). The QE carriers don't have a lot of surplus electrical power, just enough to run the ship and a bit over from their gas turbines (quick check, including some backup diesel generators they have a total electrical power capability of 109MWe). They can't drive an electromagnetic catapult system unless they build a lot of storage (probably spinning flywheels) into some space that's already committed for hangars etc.

The QE-class carriers were based on the F-35B STOVL aircraft as their primary strike fighter. There's nothing else out there with its capabilities (stealthy, Mach 2, large amount of stores etc.) that can fly off the QE decks and come back to land on them again.

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India sets June 5 as the day it will join the heavy-lift rocket club

Robert Sneddon

Labelling

The Indian Space Research Organisation (ISRO) have two launcher families, the Polar Satellite Launch Vehicle (PSLV) and the Geosynchronous Satellite Launch Vehicle (GSLV). Both launcher types can deliver payloads into LEO and GEO. The new Mk3 GSLV will be the most capable of all its launchers assuming it works but it is still well behind the Ariane V and the Falcon 9 in mass-to-orbit.

ISRO have shown they can put satellites into all of the usual orbital slots -- LEO, GEO, polar, sun-synchronous and they have even successfully launched Lunar and interplanetary probes but their existing launchers are unsophisticated designs -- the PSLV has four stages, for example.

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Britain's on the brink of a small-scale nuclear reactor revolution

Robert Sneddon

Any links?

The Chinese first concept is using a pebblebed because that's been done before (germany) and they're working along the lines of verifying each step before moving to the next one. The Pebblebed MSR should be operational in the next 2-3 year and the experimental fuel salt designs are expected to follow about 5 years later.

Can you point me to any links about this MSR pebble-bed reactor you keep on saying the Chinese are working on? Ditto for the fuel-salt MSR some people have been saying they're building right now (and they've been saying this for a long time now...).

I track the Chinese nuclear build efforts with some diligence although I tend to concentrate on actual projects with funding, sites, permissions etc. rather than vague plans and academic exercises. The only pebble-bed designs they are spending serious efforts on are helium-cooled (the experimental HTR-10 and the "production" HTR-PM). As far as I know they're not planning or funding any kind of MSR never mind having a finalised design for one, getting permission to build one, locating a site to build it on etc.

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Robert Sneddon

Pebble bed reactors

The German pebble-bed reactors (AVR, THTR-300) built in the 1970s both broke and leaked radioactive crud into the environment. The Chinese have been running their HTR-10, a small prototype helium-cooled pebble-bed reactor for about ten years on and off and they've finished building the first HTR-PM, a small (105MWe) "modular" pebble-bed reactor which is, in theory, capable of being built in quantity to generate useful amounts of electricity. As of April this year they were starting to load the HTR-PM with moderator pellets, with fuel pellets to follow later. I believe it's supposed to be operational by the end of this year but it will be going through a test and experimental operation process before they decide to build more.

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Robert Sneddon

Re: LFTR time

Yes you need uranium or other fissiles to start a thorium reactor but think of it as a starter motor and once the thorium reactor is running you can syphon out enough fissiles to start a new one relatively easily.

Thorium (Th-232) is not fissile. It needs to be bred up into U-233 in a very hot dense breeder reactor to produce lots of neutrons in a small volume to breed more U-233 and to fission that U-233 to release energy and breed and fission more U-233. Molten-salt reactor designs complicate an already difficult engineering challenge for breeding fuel by moving the incredibly radioactive fuel stream around the reactor in pipes that corrode and leak very easily.

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Robert Sneddon

Still not LFTR time

Yes, they plan to have a proof of concept reactor up and running with the next 2 years.

Where in China? Who's building it, who's funding it? What's the design, power output, fuel mix etc.?

I follow news about nuclear power projects with a great deal of interest and there's nothing about any actual funded and approved construction projects for a LFTR in China or anywhere else for that matter. There's some funding for academic studies on how an LFTR might be built, operated and eventually decommissioned but they are usually on the grad student and Ph. D. study level based on computer models and simulations with no hardware involved. There's certainly a lot of press reports and popular-magazine articles about LFTR but nothing concrete, so to speak in the real world.

The one experimental reactor actually being built in China at the moment is a 105MWe "modular" pebble-bed design (Google for "Shidaowan HTR-PM"). It will use some thorium in the pebbles eventually but it will be fuelled purely by enriched uranium to start with. It's definitely not a molten-salt design.

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Robert Sneddon

Not LFTR time

China is going all out on LFTR research and with that will emerge a whole sheaf of patents.

Really? Just how are they going "all out" on LFTR research? Do they have a reactor under construction? Do they have a firm finalised design for such a reactor? Do they have planning permission to build such a reactor, or funding to build it or a site to construct it on or anything in fact?

No, they don't. They are not going "all out" any more than the LFTR TED Talkers and the Powerpoint Rangers in the US and elsewhere are actually anywhere near realising their dream in terms of working hardware and operational experience. Sorry to disappoint.

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Robert Sneddon

AGRs, the nuclear Betamax

The Advanced Gas-cooled Reactor (AGR) was an evolutionary upgrade from the semi-militarised Magnox design and had a lot going for it such as efficiency since it runs hotter than a PWR. Unfortunately that benefit would only make it a commercial success if the fuel was rare and expensive, which it turned out not to be (the spot price for yellowcake, the product of uranium mines on May 5 2017 was about $50 a kilo).

The bad news is that our existing fleet of AGRs is life-limited because of growing flaws in the carbon moderator blocks in the core, caused by neutron fracturing of the graphite crystal structures. The cracks are not a problem now but they will get worse meaning there's no chance of extending the operation of these reactors past 40 to 45 years. In contrast many PWRs built in the 1970s and 1980s are getting their operating licences extended to 60 years and more, subject to some relatively cheap upgrades and parts replacements since they were seriously overbuilt in the first place.

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Robert Sneddon

Weird

Ummm, so much wrong, a Gish Gallop of wrong repeatedly wronged. I congratulate you, I've not seen so much sequential nuclear tech wrong since I accidentally listened to a couple of minutes of Helen Caldicott on a Youtube video.

No-one has built a LFTR ever so saying definitively what they can do is a bit of a stretch. There's a lot of Youtube videos, Powerpoint presentations and grad student TED Talks about them but no actual operational experience. The molten-salt reactor at Oak Ridge National Laboratories failed in many ways and it never ran with thorium (it used uranium). "Thorium" fuelled reactors actually burn uranium, the thorium is bred up into U-233 before being fissioned to produce energy and radioactive waste. Thorium by itself is not fissionable.

Uranium is commonplace, not rare. It's simple to refine. Sources are not limited. It is incredibly cheap to buy on the open world market and a number of large mineable deposits are not being exploited because the market is effectively saturated. Uranium as a metal is not particularly toxic, in part because the common forms are very insoluble and can't enter the bloodstream or digestive system easily. The damage, if it does cause any, is limited to some effects on the renal system. It's not evil poisonous stuff like beryllium or cadmium or arsenic or lead or a dozen other elemental toxins with low LD50 and bad neurochemical effects.

No nation extracts plutonium from civil nuclear reactor fuel[1] -- it's hopelessly contaminated with Pu-240. All of the nations with nuclear weapons made their stocks of nearly-pure Pu-239 is specialised reactors in places like Windscale and Hanford. All of those nations have more weapons-grade Pu than they will ever need, indeed it costs them to securely store the surplus after the number of weapons held was vastly reduced in the 1960s (Britain had over five hundred nukes at one time, today it has about 140 or so). Any power reactor built after the early 1970s had nothing to do with making extra nuclear material for weapons. There were a couple of designs that could be co-opted to make weapons-grade material, the British Magnox and the Russian RMBK-4 but I don't think they ever actually did since there were proper weapons-grade breeder reactors available to both nations.

[1] It's possible North Korea tried reprocessing spent commercial reactor fuel in the early days of its nuclear weapons development. The first few tests did not work out for them, you may recall.

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Robert Sneddon

Neutrons?

If fuel rods in a spent fuel storage pool are emitting neutrons then you've got problems (and Star Trek physics going on to boot).

Spent fuel rods outside a reactor are "hot" because of the radioactive decay of fission products (Cs134 and Cs137, Sr90 etc.) producing alpha and beta particles and gamma radiation. Fission has stopped since there is no chain reaction going on so no large amount of neutrons should be present.

Yes, water is a very good absorber of particles and radiation and it also acts to cool the fuel rods, preventing them from overheating and breaking apart.

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Robert Sneddon

Re: Wasn't Fukushima a "fail-safe" design?

Fission ceased at the Fukushima reactors pretty much as soon as the earthquake was detected onshore. The problem was residual heat from the decay of short-lived radioactive fission products in the fuel rods -- when running at full power reactors 2 and 3 generated about 2500MW of heat (reactor 1 was a bit smaller and produced less heat and electricity). After fission ceased the heat output from radioactive decay was about 50MW. When the cooling systems shut down due to loss of external power the cores overheated from that decay energy, not from fission.

A good rule of thumb in the metal foundry business is that 1MW will melt 1 tonne of steel if it is well-insulated so 50MW is a considerable amount of heat energy.

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Robert Sneddon

Re: "It's only a matter of time before an accident occurs involving an errant aircraft."

Someone fired a number of RPG-7 anti-tank grenades at a reactor under construction once. Nothing happened to the reactor, the fellow who said he did it get elected to the Swiss Parliament IIRC.

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Robert Sneddon

Re: Russia

Russia has built a series of fast metal-cooled reactors, the BN-family over the past fifty years or so. The current new kid on the block is the sodium-cooled BN-800 which started up a couple of years ago. It is capable of burning spent fuel, destroying waste isotopes from reprocessing, using up weapons-grade plutonium etc. but it's still experimental with new kinds of solid-metal fuel structures needing developing and testing before it can do all the things it's supposed to be able to do. It's very much experimental, they're not going to be building lots of them in a hurry. Instead they're churning out VVER-1200 pressurised-water reactors very similar to the ones that failed at Fukushima. They claim the new pressure vessels for the VVER-series reactors can be licenced to operate for a century in service due to new manufacturing and testing techniques, and pretty much everything else in a reactor can be replaced during scheduled servicing and upgrade operations.

As for the barge-mounted reactor concept they're building a couple of these to be used in northern waters to provide power to remote communities. They're using existing KLT-40S ship reactors, the sort that power their big nuclear icebreakers. They're small conventional PWR designs, not thorium or travelling-wave or anything the PowerPoint Cowboys have a hard on for. The main use for these barge-mounted reactors will be to make oil and gas exploration in the Arctic a bit easier by powering the onshore facilities, ports etc. The Chinese are also investigating this idea, in part to power the offshore islands/unsinkable aircraft carriers they're building in the Spratlys.

Lead-bismuth cooled reactors were a design used in some Soviet nuclear subs. I understand they were not a technical success with some problems in controlling the reaction in various operating modes -- ship and sub reactor output levels get swung from low-power to high-power a lot and that makes for tricky nuclear chemistry in some situations (Xe-135 poisoning of the fission process, for example).

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Robert Sneddon

Pebble Bed reactors

The two German pebble-bed reactors both broke and one released noticeable amounts of radioactive material into the atmosphere. They still don't know exactly how to safely decommission them (Google THTR-300 and AVR for details) so they're mothballed until the radioactivity dies down a bit more.

The Chinese have been operating a small high-temperature pebble-bed reactor for a while now, the HTR-10 (it generates 10MW of electricity). They're building a bigger version which is sort-of modular, a 105MW reactor that will work in pairs to drive a 210MW turbine. The vague plan is to site a dozen or so of these together to make one complete generating plant but they want to see how the scaled-up version works before they start mass production.

As for submarine and other propulstion reactors, the modern cost-no-object designs used in the US Ford class carriers and British Astute subs run on bomb-grade uranium enriched to 90%. Having this sort of stuff sitting around in civilian hands in regular power reactors is a bit of a proliferation risk. The US and other nations have been working to replace existing highly-enriched (but still nowhere near bomb-grade) cores in some research reactors with low-enrichment fuel cores.

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DeX Station: Samsung's Windows-killer is ready for prime time

Robert Sneddon

What happens...

"Docking stations are supposed to be stationary. You come into the office, place your phone into the docking cradle..."

What happens if you arrive at the office and discover your phone is still at home/broken/riddled with viruses thanks to little Tarquin/ANother? Go home for the day?

I suppose the office could have a few loaner phones for the careless or unlucky, or they could just have a cheap desktop PC attached to the peripherals the phone dock is connected to, with secure Ethernet connections to the company systems etc. and your phone is relegated to Facebook and Angry Birds duty during your break times. There's also less chance of someone walking out of the building with the customer contacts DB on their personal phone's internal storage...

I can certainly see a use case for a phone dock like this at home but for businesses? Not really.

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Tesla: Revenues up, losses deepen, in start to 'exciting' 2017

Robert Sneddon

Optional extras

So buy your car, then your solar panels/tiles and a battery array, which adds to the TCO for the car

Don't forget the freestanding or semi-detached home to put those solar cells on and a garage or other facility to house the charging station and storage battery. That adds a chunk to the TCO.

Lots of people in the UK and elsewhere don't have a roof or a garden to put solar cells and a kickass battery pack or an off-road location to park their car. They rent their property and/or live in a block of flats in a city centre with a roof covering several properties and restricted public parking. This will make plug-in-only electric vehicles a high-end option for quite some time to come.

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Yeah, keep buying those SSDs, grins Seagate: Your data will be on our disks eventually, muaha

Robert Sneddon

Backups, backups, backups

One backup is no backup. Two backups is a start. Three backups is getting somewhere, with at least one of them offsite and I'm not talking about that cloudy-woudy thing.

RAID or similar is not a backup, it is only a method of improving uptime locally.

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Drunk user blow-dried laptop after dog lifted its leg over the keyboard

Robert Sneddon

Doggy piddle

My flatmate had a visit from a friend with a yap-dog. I unwisely left the door of my room open and said yap-dog came in while my back was turned and proceeded to "lay claim" to the HP LJ4 sitting on my floor, right in the ventilation slots.

I powered it down, got out the big rubber gloves and cleaned it out and it worked fine ever after. The carpet was another matter...

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China successfully launches its first robot space truck

Robert Sneddon

Dragon capsule capacity and capability

The SpaceX Dragon capsule used for cargo launches to the ISS usually carries about three tonnes or so of supplies on each flight, not six. It can't transfer fuel and other liquids to the station via the docking port adapter and it can't dock automatically, it's captured by a robotic arm under manual control. It can return scientific samples, equipment and other materiel to Earth which no other unmanned capsule can.

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Nerd Klaxon: Barbican to host Science Fiction exhibition this summer

Robert Sneddon

Gilgamesh

One of the earliest stories known, Gilgamesh is putatively SF with supernatural elements and wild impossibilities -- one of the key requirements of a good SF story is engaging the reader's Willing Suspension Of Disbelief (WSOD) and anything that noticeably distorts reality needs some serious WSOD for the reader to stay engaged with the story.

As for adventures, the definition "Bad things happening to people I don't personally know a long way from where I'm sitting comfortably reading about them" springs to mind.

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Customer satisfaction is our highest priority… OK, maybe second-highest… or third...

Robert Sneddon

Re: Card - no

Which kind of claymore, the long pointy stick kind or the gently-curved plastic slab with "this side towards enemy" stencilled on it?

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Robert Sneddon

Re: "coffee please"

"Captain Vimes will have it boiled orange in a builder's boot with two sugars and yesterday's milk."

Proper copper tea.

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Linus Torvalds lashes devs who 'screw all the rules and processes' and send him 'crap'

Robert Sneddon

Testing Testing Testing

"How can anyone working towards something as important as the Linux kernel not do at least at much?"

Nobody has created comprehensive code testing processes for Linux. Nobody is continuously improving those testing processes. Nobody is working to ensure all code submitted gets tested to a high standard. Nobody is paying them to test their own code. Nobody is standing over them ordering to test their code. Nobody gets their code and tests it independently. Nobody reviews their code. Nobody provides the sort of expensive hardware systems to run exhaustive tests on their code to ensure a high level of hardware compatibility over multiple platforms (not just two or three).

Linux is Open Source written in the main by folks who are doing it as a hobby. I have a vision of Mr. Torvalds standing up on a stage screaming "Testers! Testers! Testers!" while throwing chairs.

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LOST IN SPAAAAAACE! SpaceX aborts Space Station podule berthing

Robert Sneddon

Busy car park

The Dragon capsule is hooked by a robotic arm once it approaches close enough and is then coupled to an airlock in the middle of the ISS. The Soyuz Progress capsules dock automatically at the far end of the station where they can transfer liquids and fuel as well as boost the ISS and raise its orbit by firing the service module's main engines. This means there's no need for one cargo capsule to get out of the way of the other to find a parking space. Usually though the mission controllers don't like two ships manoeuvering around the ISS at the same time so they'll probably prioritise one docking operation over the other.

I think the record for number of cargo and passenger ships at the ISS at one time was six, including a Space Shuttle as well as an ATV launched by ESA but none of them docked while the others were still in free flight near the station itself.

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Clone it? Sure. Beat it? Maybe. Why not build your own AWS?

Robert Sneddon

Down as well as up

Renting services from AWS or other providers makes sense if you carry out projects that might fail (such as the CEO's pet buzzword du jour concept) or have a fixed lifespan (such as migrating to new services) -- a year down the line you can simply trash the data and tell the provider the monthly contact is at an end. The alternative is to be paying for hardware and premises that you built out for a project but have little use for now (until the CEO hears a new buzzword...)

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In colossal shock, Uber alleged to be wretched hive of sexism, craven managerial ass-covering

Robert Sneddon

Part-timers

There was a case about a year ago of an American Uber driver working the late shift who was shooting people in drive-bys between picking up passengers.

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Installing disks is basically LEGO, right? This admin failed LEGO

Robert Sneddon

Large rubber mallet job

I got a defunct 2U server cheap off a site clearance, planning to break it for parts. It had apparently stopped working in the rack and been taken out to be fixed but no-one could get it to power up so the HDDs were pulled and it was left on the workshop shelf until the annual turf-out of old and broken kit came round.

A couple of minutes under the hood revealed both hot-swap power supplies had been inserted upside down in their docks with sufficient force (quite a lot, really) to bend the PSU mating connector structure inside the server out of the way far enough for the retaining latches at the back of the PSUs to snap into place. For some reason the designers hadn't polarised the PSUs and the docks to prevent this happening in the first place. A minute or so with a rubber mallet bent the mating connector frame back into alignment, I put the PSUs back in the correct way round this time and the server powered up perfectly.

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All of Blighty's attack submarines are out of action – report

Robert Sneddon

Battleship inflation

The Royal Navy had a lot more subs thirty years ago but about half of them were diesel boats built in the 1960s and 1970s. The first nuclear submarines were in the 3000-4000 tonne displacement range, effectively large diesel-style hulls with a nuclear power plant providing steam to conventional turbines or (later) pumpjets for propulsion. They had operational problems including requiring refuelling every ten to fifteen years which necessitated the hull being cut in half to get at the reactor spaces which took them out of action for years at a time.

The new Astute class boats are 7000 tonnes plus, use electric drive resulting in extraordinarily low levels of noise, carry cruise missiles as well as a massive towed sonar suite, cruise underwater at thirty knots plus, never need refuelling due to improvements in reactor design and they can do all sorts of things the older subs can't. The downside is they're much larger and more expensive to build than their predecessors so we get fewer of them. It's like the old battleships which got bigger and more expensive as time went on but fewer and fewer got built for the same reasons.

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USMC: We want more F-35s per year than you Limeys will get in half a decade

Robert Sneddon

The Bad Guys shoot back

"An A-10/Harrier can get in close on a strafing run within a couple hundred feet, "

The Bad Guys, even irregular guerilla forces usually have heavy machine guns that can shoot back if a ground attack aircraft gets within "a couple hundred feet". Pilots that want to go home after work shoot up the Bad Guys from a few kilometres away using Hellfire and Brimstone missiles from well out of range of heavy MGs and shoulder-fired missiles. As a bonus they don't accidentally walk cannonfire through friendly forces when the nose of the aircraft drops in a rough air pocket.

A sniper wouldn't charge his target to bayonet them, why would it be necessary for ground attack aircraft to knife-fight when they can stand off beyond visual range and turn the opposition into mince without allowing them a glimpse of the weapons platform that is destroying them?

As for the Harrier, a triumph of 1970s engineering, it is slow and short-ranged with a limited payload compared to regular catapult-launched aircraft such as the F/A-18. Its big advantage for the USMC is its ability to operate from rough airfields and short decks on the Tarawa-class and new America-class Marine assault ships, America's other aircraft carriers. The F35-B can also fly off those short decks as well as being faster, longer-ranged, smarter, stealthier and generally isn't falling apart due to the age of the airframe hence the USMC's keen interest in getting more of them as soon as possible to replace their forty-year-old Harriers.

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Would you like to know why I get a lot of action at night?

Robert Sneddon

Shinkansens

No WiFi, free or paid-for in shinkansens but there are power sockets. They're at every seat row in some trains down near the floor or just at the front and back of the carriage in other trains.

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BOFH: Password HELL. For you, mate, not for me

Robert Sneddon

Reverse engineering

Doing contract support at $Large Financial Organisation I temporarily needed a better login than the one I had to do something dangerous and irreversible without leaving (my) fingerprints in the logs if shit went wrong, so I asked my manager for his login and password which he gave me quite happily... The password ended in 22. Knowing the AD enforced password changes for security purposes every two weeks I speculated he had been there for about 10 months or so.

"How did you guess?"

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Modular dud drags LG to first loss in six years

Robert Sneddon

Panasonic

sells a ruggedised phone with add-on modules. It's a tech tool though, not consumer oriented -- if you want a laser barcode scanner or a real serial port on your phone you pay serious money for it.

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IT team sent dirt file to Police as they all bailed from abusive workplace

Robert Sneddon

Hired Guns

The Union representative will probably be one of your co-workers. The Union lawyer at your side during the Interview with HR and senior management is your employee and she faces down bigger bastards than them five days a week.

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Robert Sneddon

Fruit of the Poisoned Tree

"UK courts do not have that doctrine. Nor do most commonwealth ones."

A long time back I was a witness in a Scottish court giving evidence and heard the defending counsel say those words to the justice. The case was about property theft from a company I had worked for and the "fruit" assertion was, as I understood it, that the chain of custody of the physical evidence was broken in some way.

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Britain collects new naval tanker a mere 18 months late

Robert Sneddon
Pirate

Cabling and paperwork

The South Koreans have a track record of covering up bad cabling installs with fake paperwork. Several of their nuclear reactors were taken offline a few years back when it was discovered cable suppliers had faked up certification of the control and power wiring in the reactor buildings. The operators had to rip out and rewire the reactors to spec before they were permitted to restart them. This delay to the RN's acceptance of the Tidewater may have been something along the same lines.

The South Koreans produce some decent bits of kit but they have major institutional corruption problems in government and industry.

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Japan's terrifying techno-toilets will be made foreigner friendly, vow makers

Robert Sneddon

Re: Aliens

There was the Twin Choron bar on a space station visited by Earthlings -- it had three doors marked "Oozers", "Squirters" and "Emitters". They decided they could hold it until they got back to their own ship.

("Illegal Aliens" by Phil Foglio and Nick Pollotta).

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Google nukes ad-blocker AdNauseam, sweeps remains out of Chrome Web Store

Robert Sneddon

Firefox is blocking extensions too

The latest builds of Firefox block the use of unsigned and unapproved extensions. I switched some of my browsing to Pale Moon so I could run a couple of old "Jet Pack" extensions that no-one is maintaining since the Pale Moon developers said they would continue to allow unsigned extensions to run. The next release of Pale Moon kicked Jet Pack to the curb...

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Meet the Internet of big, lethal Things

Robert Sneddon

Farming is not a hobby

"I've heard EFF argue that "who knows their land and equipment more than the farmer who owns it?"

Actually, for most farmers the land and equipment belongs to the bank that provides the overdrafts and loans to buy said land and equipment.

Someone I knew was the last of a farming family which worked land in Lincolnshire for about 150 years. He said that at no time in the family history as recorded in the account books he knew of did they ever own the land outright, it was always mortgaged up to the hilt. In a good year they didn't have to give most of their earnings to the bank at the end of the year to service the loans, in a bad year they had to extend their borrowings to buy seed for the next year's plantings.

He fixed the heavy machinery on the farm himself when he could but he knew the older models of tractors, seed drills and combines were less efficient, more work for the "owners" and more likely to break down at the wrong time because they didn't have the sensors and monitoring software that would give him a heads-up and book a visit from an engineer to carry out preventative maintenance, leaving him more time to actually farm the land the bank owned.

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NASA – get this – just launched 8 satellites from a rocket dropped from a plane at 40,000ft

Robert Sneddon

Efficiency and convenience but not that much of a boost

There are a couple of benefits of air launch such as flexibility in where the launch takes place from (basically anywhere a couple of hours flying time from a suitably large runway) and fewer problems with weather on the ground or range safety which can abort or hold a launch at the last minute.

Rockets work better in vacuum or close to it since there's less back pressure so an air launch at altitude is more efficient, but only by about 10% or so.

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DDoS script kiddies are also... actual kiddies, Europol arrests reveal

Robert Sneddon

Criminals, not the sharpest SSD in the SAN.

The one thing that stops people committing crimes is the fear of being caught. Tough sentences etc. have no real effect. The bad news is that habitual criminals don't think they'll be caught, even after they have been caught many times before. This time it's going to be different, they think. They're usually pretty stupid and have little impulse control. Drink and drugs don't help.

https://www.youtube.com/watch?v=nvmYfcQB5HY

There are a lot of court cases where someone does get caught early on, first-time offenders and they learn their lesson, grow out of it or give up and live a mostly crime-free life as upstanding members of the community, only evading taxes, speeding, drinking and driving, working off the books, taking backhanders etc. It's the 19-year-old with sixty-odd convictions for burglary and aggravated assault that makes the headlines but they are very much outliers.

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NASA spunks $127m on SSL-powered robot to refuel satellites in space

Robert Sneddon

It doesn't work that way

Delta V is the total change in velocity of an object, its vector as well as its speed. A low delta V means the robot wouldn't get to its required position in space travelling at the correct speed in the correct direction (vector).

A rocket motor produces a given amount of thrust per unit of fuel and oxidiser burned, the so-called specific impulse (Isp). Using it up slowly or quickly doesn't make a difference to the total amount of fuel needed to rendezvous with a target, at least in free flight in space where air friction etc. is not a factor.

Electric thrusters like ion engines are very efficient in terms of Isp but they have very low thrust -- the engine that propelled the SMART 1 probe to the Moon had an Isp of about 1600, more than four times the best chemical rocket engines but it could only generate 68 milliNewtons of force using xenon as fuel.

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Robert Sneddon

Re: Yikes

ESA and the Russians have flown refuelling robots several dozen times quite successfully. The International Space Station has thrusters to provide attitude control and some repositioning capability, to dodge space debris mostly. The Soyuz Progress capsules and the ESA ATV modules both have the capability to transfer fuel to the ISS as well as liquids such as water, ammonia etc.

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Chernobyl cover-up: Giant shield rolled over nuclear reactor remains

Robert Sneddon

Hot and fast or cold and slow

Effects on biological tissue from radioactive materials are not simple to evaluate for a lot of reasons. The rules and guidelines on exposure and intake currently in place are the result of a lot of empirical data and lab testing plus a fudge factor on top i.e. the maximum exposure permitted might be 10% or less of a dosage that produces any noticeable effect at all in trials. There's also the As Low As Reasonably Achievable (ALARA) limits which presuppose people shouldn't be exposed to any amounts of man-made radioactive materials at all. Radiation from natural (organic, free-range, cruelty-free, vegan-friendly) isotopes such as potassium-40, carbon-14 and others are tacitly ignored in these limit settings since there's nothing anyone can do to avoid them.

Radioactive isotopes with a short half-life are very "hot" so a small amount will do a lot of damage but it stops being a problem after a few hours, days or weeks. I-131 is one example of a problematic isotope in an accident, with a half-life of 8.5 days so it's "hot" plus it concentrates in the human thyroid gland like regular iodine. That fast decay rate means that a few weeks after any release it stops being a problem.

Very-long lived radioactive materials like U-235 (half-life 700 million years) and U-238 (4 billion years) aren't particularly dangerous in terms of the radiation they produce. They'll be around for a long time but they're not "hot" even in large quantities. It's the medium-life isotopes that escape an accident site that are really a problem -- Cs-137 and Sr-90 are the usual suspects here with half-lives of about 30 years.

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Robert Sneddon

The other major radiation release that week...

Even funnier, a couple of days after Chernobyl 4 burned to atmosphere a German pebble-bed reactor, the THTR-300 released some radioactive particles into the air after a fuel pebble broke up in its feed channel. The operators tried to cover it up, hoping nobody would notice the release because of the Chernobyl contamination but some isotopic analysis showed it couldn't have come from the Ukraine-based reactor and they got caught.

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Airbus flies new plane for the first time

Robert Sneddon
Angel

Knock in Ireland

has an international airport, the fourth largest in Eire. It's there to handle the half-million or so Catholic pilgrims who visit the nearby shrine every year. Religion is big business in the travel industry.

Oh, and Lourdes? From the Wiki article on the airport at Knock:

"On 1 June 2003, hundreds of people gathered to view an Air Atlanta Icelandic Boeing 747 land with 500 returning pilgrims from Lourdes."

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New state of matter discovered by superconductivity gurus

Robert Sneddon

Re: Yttrium Barium Copper Oxide

I was working in Cambridge when the first LN2-temp superconductors were discovered -- the pub convos were *interesting*. People were frantically trying to get hold of quantities of yttrium and other odd elements. I suggested they try contacting Brock's Fireworks.

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Robert Sneddon

Re: using liquid helium or liquid nitrogen, which is expensive.

There's more helium in the atmosphere than xenon. If the cheap helium (sourced from some natural gas wells) runs out it can be scavenged from the atmosphere like xenon. The price tag just goes up, that's all.

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ESA lofts one astronaut and four Galileo satellites into orbit

Robert Sneddon

Orbits and energy budgets

Geosync satellites are placed in an equatorial orbit but the Galileo satellites, although in a lower orbit are flying in a ball-of-string pattern at different angles to the equator. This single ES-variant Ariane V flight had to deliver the four satellites into different orbits hence the use of a new upper stage "dispenser" with a restartable engine that carried out multiple burns to do the job.

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