I imagine that the problem with making the oil very hot is that losses to the surrounding air by convection increase rapidly with themperature.
2623 posts • joined 10 Jun 2009
I imagine that the problem with making the oil very hot is that losses to the surrounding air by convection increase rapidly with themperature.
I must have missed something. If you want to heat water from solar PV electricity, don't you just put a 12V or 24V immersion heater in your tank and connect the raw DC solar panel output to the heater?
I would have thought that the rest involves a motorized switch to connect the panels to the inverter or to the water tank as desired. If inverters are allergic to being completely disconnected from their PV panels at short notice, you could switch between all the PV output going to the inverter, and the PV output going to the inverter and the water-heater in parallel.
And if you also want to be able to heat water from mains electricity, just put a second immersion heater in the tank. OK, it may be hard to source a tank with two bastard curcular cut-outs at the top for screwing your immersion heaters into. I find that struggling with one is quite enough!
Back to the original idea, surely there's such enormous thermal inertia in a water tank that you wouldn't have to switch the heater on and off more than once every few minutes. Flicker regulations?
Knock on the door of whoever is paying for the broadband, of course. I'd suggest that would be the "Borchester Village Internet Co-op" or suchlike. Obviously take appropriate software precautions so that only authorized users get access (such as end-to-end as an encrypted pipe, and some logging of who and when).
Not really any different to any other smallish not-for-profit's set-up, apart from the wireless pipe to the broadband connection location.
Same idea as rural networking, but a different application, for brave people living under repressive regimes. Build your own hidden communications network.
This more or less happened in Libya, although the rebels "stole" the existing wireless network infrastructure rather than just installing their own.
It's not a new idea at all. Years ago I read about the installation of a working telephone booth at the Burning Man festival, using a chain of off-the-shelf routers strung across the Nevada desert. It's just that it's getting more affordable, and the RPi lets you integrate things like battery and power management to a greater degree. There are also quite a few routers that one can "jail-break" and convert into small fully programmable Linux boxes. (OpenWRT, etc.)
A related idea would be just to use a pair of solar-powered RPIs (or OpenWRT boxes) to wirelessly bridge a road. This is useful, because while you might persuade a few landowners to let you string a fibre across their land, just try getting permission to take a fibre over or even under a public highway. So, don't try. Just put a solar-powered fibre-to-wireless router on each side. You wouldn't even need directional antennae (which may not be entirely legal).
Victorian terrace should be easy! It has floorboards? You can push your low-voltage low-bandwidth wiring into the cracks between the boards in ine direction, and pull wires through the space between the joists under the floorboards in the other. Modern flat with a solid concrete floor is harder, though if you have carpet you can also easily put wiring under the carpet.
Very thin copper wire or tape attached to a wall, wallpaper-glued down with tissue paper and painted over would probably also work. I once attached a multi-element FM antenna to a ceiling that way (antenna made of aluminium foil, then papered over and painted). Worked a lot better than a dangly wire, and a lot cheaper than getting a man to attach a proper antenna to the chimney. The room needed painting anyway.
Or with RPi at £30 ... go wireless?
Fairly challenging, but a case of open-source development once, fix hundreds of thousands of people's problem.
It ought to be possible to connect an Rpi, a solar panel, a battery, a weatherproof box, a USB hub, some USB wireless thingies and some directional antennae, to make a goes-anywhere wireless access point. Stick that on a pole in a field somewhere, with line of sight to another pole, and another, and another ... chain them together from a location that can get broadband, to a village or hamlet that can't.
Software that auto-assembles a network, so apart from configuring the broadband end the future problem abounts to errecting poles, screwing a box onto the top, and pointing the antennae in appropriate directions.
It's a cheap somewhat limited implementation of something that the military are playing with for battlefield communications, and disaster relief agencies for getting communications up again after a natural disaster.
in particular, the Thorium cycle: breed U233 from Th232, and then fission the U233. Takes a lot more neutrons to get all the way up from U233 to Plutonium, so production of Plutonium will be minimal.
U235 production might be more of a worry, but it involves isotope separation to extract it rather than chemistry. Hard to build a Uranium isotope separation plant without being noticed.
So, don't patronise us and tell us to grow up for lamenting the removal of the option to exercise choice.
But your freedom to choose to block adverts has not been removed. It's just that the Google store has stopped stocking that app, so you have to get it from somewhere else and learn an extra trick or two to install it. To me, it's a bit like your default supermarket deciding not to stock one of your favourite products. Annoying.
If they'd made it impossible to block adverts without voiding your phone's warranty, THAT would be interfering with your freedom of choice. If they'd used cryptographic techniques so it was impossible to install anything they didn't want you to, and so they could retroactively take away something that they didn't want you to have , that would qualify as evil. Nobody could be that nasty, could they?... Oh.
We can't even work out how to communicate with cetaceans. What chance have we got with something with which we share no common ancestry at all?
(They sometimes save our lives by swimming us back to dry land. That shows a remarkable capacity for abstract reasoning by dolphins and orcas, and inter-species empathy in advance of our own. )
Which has just made me think, why haven't I ever seen use of kK or MK? (temperatures appropriate for describing stars).
(Unlike the Yg, which isn't NEARLY big enough).
Even if they happen to be within a few tens of light-years, even if they are currently watching Lucille Ball on Earth-TV and trying to work out what those strange techno-primitives are up to, they may still be thwarted by real-world physics. In other words, they've come to the same conclusion that our scientists have, that interstellar travel isn't ever going to happen outside of the movies. No wormholes, warp drives, ZPE drives, reactionless drives, or any of the other devices that SF authors use to get an interstellar plot going. Just rocketry and relativity and radiobiology, saying "can't be done".
My riposte to the (strong) Anthropic principle is that the universe is NOT optimised for Homo Sapiens. It's optimised for our silicon successors, who'll be able to slow their clock rates down so that a thousand light-years becomes a few years subjective. They'll prefer just about anywhere in the universe to those hot balls with moist oxidizing atmospheres, where some (mostly ridiculed) few amongst them think their ancestors must have developed, back before the Archives and the Memories.
In the worst-case scenario, they're here in our Oort clouds already, we're making far too much noise, and they're getting ready to drop a comet on us. (It worked last time, 65 Myears ago).
Premise is utterly bonkers. A bad fantasy. No science at all. Newton would have discovering relativity as a consequemnce of how fast he'd be spinning in his grave. Even "The day after Tomorrow" made more sense.
It's a brilliant movie and has an SFnal framing device, but does it really count as an SF movie? If it does, what about the even more brilliant "Brazil"?
At last. I was thinking I was the only person who thought it a worthy contender to replace Zardoz.
They could move away, just as AMD managed a transparent shift from i686 to x86.
The easiest route might be something like a bigLITTLE architecture with ARM cores and x86 cores on the same die, sharing cache, memory controller and maybe other internals. Gradually shift the balance of core provision towards more ARM cores and less x86 ones, as software takes advantage of the new feature.
The ARM architecture is intrinsically more efficient than x86. If one could compare an ARM CPU against an x86 CPU implemented using the exact same fab process, ARM would win. (OK, for flat-out number-crunching the design of the FPU also becomes a very significant factor and Intel may have a sufficient edge to win here - thought Nvidia does it even better if you can run on a GPGPU instead of a CPU).
At present you can get an intrinsically inefficient x86 CPU implemented on Intel's proprietary process, or an ARM CPU handicapped by an inferior process, and the result is something close to a tie.
it was a coding error from someone who thought "hey, she will only fly for a few hours however, so why bother".
Someone thought that way in safety-critical code? Please reassure me it was just the in-flight entertainment system.
Where's the scream icon?
Out of interest - how much weight does the Lithium battery save, compared to an NiMH stack of the same capacity?
Would lead-acid be allowed in an aircraft? Spilled acid in an airframe would be very undesirable, even if gelled. Even more so, the hydrogen gas that the things emit under failure / overcharge conditions or when spilled acid finds something metal to react with.
Indeed. What we have here is an very unsurprising demonstration that the ruling party in a post-communist but still centralist, controlling and repressive state doesn't understand open-source. It's a bit like expecting a mole to understand flying.
Walled garden versus open source is an old discussion. Evidence so far is that given enough time, open-source always wins. Recently Apple, with its massive first-mover advantage, is losing ground to Android. But that's just a recent skirmish in a war that's been going on since bacteria developed plasmids, and higher organisms developed sex - both means for spreading their source codes as far and as wide as possible, and for maximising the amount of development thereof. (Mutually synergistic, of course).
I'm reminded of the USA experts laughing at the USSR's avionics in a defector's jet, that still used thermionic valves (tiny peanut-sized ones).
Until someone pointed out that valves are EMP-proof, and transistors aren't.
Seagate website says "no price or purchase options available". Sigh.
I'm surprised no-one has mentioned this possibility (or impossibility, depending on quantum gravity and other physics we don't know much of). Wonder if there's any hope of learning more by studying this beast from the very great distance we're at.
For a long time it's offended me that most datacentres are busy throwing away heat to the air outside, while the same building is burning fuel to keep its inside warm for the people that work there.
In fact one can source airconditioning plant that pumps heat from the air in the server farm "uphill" into the building's central heating system. However such plant has a higher capital cost, and the IT people and the estates people and the finance people don't properly talk to each other and argue over "whose budget" rather than seeing the "interest" on the capital invested (arriving by way of a reduced fuel bill). So it's rare to find such a system. Personally I'd say legislation or tax breaks should make such airconditioning either compulsory or highly tax-advantaged.
CPUs are happy running at 80C so they could be "cooled" by water from a central heating system. Trouble is that water and electricity don't mix. The tiniest leak from the CPU cooling circuit can trash the motherboard. Cue a nonconductive inert liquid which could be pumped through heatsinks above the CPUs and then through a heat-exchanger plumbed into the central heating system, with no aircon (pumping of heat uphill) required.
Looking further ahead our CPUs could be happily running at 100C or even 120C if they were designed and tested to do so. Nothing in the physics says it can't be done. They'd slow down in proportion to the increase in absolute temperature: 60C to 120C is 333K to 393K, so that's about 20% slower. In most environments a couple of extra cores on the chip would be adequate compensation for the lost MHz.
In all seriousness, shouldn't the Mormons buy this site and run it forever free and advert-free? All they have to do is convert one of the still-living, and all those ancestors are instantly saved.
Does anyone know for sure whether the Firefox Flashblock plug-in (which I use) is a generic fix for these problems in respect of any flash stuff that you don't actually choose to display? In other words does flashblock keep the flash data strictly away from the flash code until you click on the logo?
Short of scrapping patents or drastically modifying what is patentable, how about this?
The plaintiff should be obliged to pay for the defense as well, on a dollar-for-dollar basis. If he won, he would be awarded costs that cover all the money he paid for the defense as well.
This would mean that small companies would no longer fear being sued by a bigger outfit with deep pockets. They could never be forced to concede, because the cost of defending their patent would be even greater than the cost of paying for a license from a troll.
I've found myself wondering about submillimeter (Terahertz) directional antennas, and moth antennae. Do moths get completely confused by artificial lights not because they emit light, but because they're a strong source of THz emission? Just a thought. Has anyone tested moths' response to a completely cold light source (ie one that's not also strongly emitting at THz? )
Combustion of a "body" has been demonstrated, using a pig carcass dressed in clothes in place of a human body. No mystery.
Better still to buy some hybrid rechargeable AAs and a charger, so you use the same batteries over and over again. (Hybrid NiMH are the ones that will stay charged for many months - ordinary NiMH go flat in about two).
My DAB radio needs new batteries every week. Progress? I think not , but it does let me listen to BBC World service in my bathroom. Thank heaven for rechargeables. Must be approaching their 200th recharge by now.
Clockwork and dynamos are very old ideas. Putting them together to power a radio shouldn't be patentable. By all means register your design so that others can't copy it exactly. By all means patent any mechanical widget that makes the clockwork dynamo work better than it ever could without that widget - if there is such a widget involved.
But patenting a concept that amounts to connecting a radio to a power source ought to have been thrown out by the patent examiners! Even if there wasn't any prior art for clockwork radios, it STILL shouldn't be possible to patent the concept.
Whatever next - a patent on kiddies' play bricks with rounded corners? Oh, wait a moment ....
It's literally boiling the water in the atmosphere as it comes in.
A masterly understatement. It's literally boiling the iron or whatever that it's made of. It's probably going past that, all the way to plasma. Afterwards, the iron, silicon, whatever condenses (as oxide, mostly) and hence the thick trail.
If you watch the car footage you can actually see the trail appearing to burn for a few seconds. I expect that's a Nitrogen - Oxygen fire, or possibly or additionally an Oxygen - Iron fire if the meteor was iron.
One of the worries prior to testing the first nuclear bomb was that it would ignite an (exothermic) Oxygen - Nitrogen combustion, that some thought might propagate to consume the Earth's entire atmosphere and everything living therein. I wonder if someone else pointed out that were that possible, a meteor strike would have done it long ago? Or did they just chance it?
My thought too. Are Russians completely unflappable, or is it a language where excitement is conveyed through choice of words rather than tone of voice?
It's even more noticeable in the other video, of people when the shockwave arrives and smashes loads of windows.
"Should have been vertical". You must be a troll. No-one can be that thick around here, surely?
Almost horizontal means that its intersect with the Earth just clipped our atmosphere. Dumped most of its energy at a decent altitude. Bloody good thing too. If that had come in much closer to vertical it would have been far more destructive of whatever was underneath.
Much better if society can be persuaded to mount an "immune response" BEFORE the next outbreak of ethnic cleansing, rather than after.
A lesson from history. In the late 19th century the unified state of Germany was formed to great public acclaim. Its new citizens queued up to obtain their papers. The form they filled in was quite simple. One of the questions was "Religion" to which many happily replied "Jewish". After all, this new state had for the first time granted them constitutional protection against harassment and discrimination.
Scroll forwards to the late 1930s and their parents' replies stored in dusty filing cabinets doomed not just the parents, but children and grandchildren not even born at the time.
For far too long councils and other quasi-governmental bodies have been recording our racial details for no good reason. What business is it of theirs whether someone applying for planning permission or a parking permit is black, white or green?
Anyway, perhaps now we can request all the data that they hold about us and the reason keeping it, point out that it was obtained coercively and that we do not consent to them storing or processing it.
Personally, I always tick the "Other" box and write "Human". It's only been rejected once.
people like me will get sick of trying to retrain them and just go with linux instead.
There's also Linux-lite, aka OpenOffice / LibreOffice running on a Windows PC. It's probably easier to re-train someone off Office 2003 onto OpenOffice, than it is to re-train them onto Office 2007. And the OO folks seem mercifully free of the desire to inflict new interfaces on their users in order to look cool.
And of course the price of OO / LO is very competitive indeed.
I'm surprised that the obvious seems to have been missed. Busses spend a lot of time stopped at predefined locations - bus stops. Put the induction chargers at the stops (only). Give the busses some sort of secure-ID so that the charging turns on only when there's a bus at the stop. Installation cost greatly reduced, freeloader problem greatly recuced. Add yellow lines and discharge monitoring and cameras for further defense against freeloaders.
Blow? Hole? Continu??!!!!!!!!
No, the day after they turn it up to full, they should announce that they accidentally destroyed the universe last night, but nobody apart from a few particle physicists actually noticed.
Many scholars have tried and failed to crack Etruscan. There's no Rosetta stone. If this program can crack it, then it's a major advance. If not ....
Have they tested it on Basque, absent any help from a speaker of that language? Again that would be an acid-test. Banque is one of the world's anomalous languages, not related to any other in any known way.
I'd really have liked to see that review also compare a hybrid drive such as Seagate Momentus. Yes, it's a slow sleepy 2.5 inch laptop drive, but how much difference does that built-in flash cache make? And being out past the drive end of the SATA connector, it'll work with Linux or anything else you care to boot.
With Linux it is trivially easy to put the operating system and your own small / heavily accessed files onto a small SSD. One can configure a completely useful Linux system in 30Gb (about 15Gb of system files, 15Gb /home). Unfortunately 30Gb SSDs are slower than 256Gb ones, but they share the same near-zero seek time. Again it would be nice to see that benchmarked.
For some criminals, especially the violent ones, you are right. Some aren't deterred. Their crime doesn't make any economic sense in the first place. But I'm fairly sure that most of those who steal for a living consider their personal risk-reward ratio. Upside: ££££. Downside: self-assessed cost of punishment times chance of being caught. Commit crime if upside > downside. Especially so for those whose crime is planned rather than impulsive.
Crimes against infrastructure cost society a large multiple of the gain to the criminal, and the sentence should therefore be disproportionately heavy. The criminals won't suddenly go straight. But they will go back to the sort of crime where the gain to the criminal approximately equals the loss to the victim or his insurer. In other words they'd stop nicking cable, and go back to nicking cars or breaking into banks, and society at large would be better-off.
That's more than you'd get for rape or manslaughter.
And arguably it should be. With those crimes there is one victim, seriously affected. With cable theft there are hundreds, thousands, even millions of victims.
At present they are getting away with it. In wartime it would be called "sabotage" and would be seen as a capital crime, punished much the same as treason. An appointment with the hangman would be quite likely.
Personally I'd say work out the economic damage caused by crimes that wilfully damage infrastructures, and sentence them to what they'd get for stealing the same amount of money from a bank's safe. What would yet get for breaking into a safe and emptying it of a million quid? Five to ten years sounds about right.
And the best thing is that with this sort of crime, one heavy sentence would convince just about all criminals to go back to the sort of theft where there is only one victim, where the gain to the criminal is not a tiny fraction of the cost to society.
For warrantied quality, buy enterprise-grade drives. They do cost about twice as much as bog-standard desktop ones, though. Personally I'd much prefer two drives mirrored - one made by WD and the other by Seagate, so as to minimize the chance of both coming from the same defective batch. But that's not an option in a laptop.
Other folks aren't having the same problem. It would be the number one story in the tech press if they were.
Did you buy all your drives in one batch? (Or all the PCs containing the drives in one batch? ) If so, the likely explanation is that all the drives are the same production batch, which contained a defective component. If PCs were cars, there would have been a recall.
Talk hard with the supplier. You need all the non-failed drives in the batch replaced a.s.a.p. and it should not be at your expense. (Although you're probably better biting that bullet anyway, if the drives are out of warranty and the PC vendor has gone out of business).
At my workplace we buy a couple of hundred PCs every year, and the reliability we've seen hasn't changed noticeably over the last five years.
Yes, SMR plus a big flash cache managed by the drive firmware sounds very plausible. I can't help observing that Seagate is the company that springs to mind in connection with flash-cache drives.
Also yes, one will need to be very careful that if one is doing server-style things with desktop rather than enterprise drives, one doesn't accidentally buy an SMR drive. (I have visions of someone replacing a 2Tb drive in a RAID-5 array with a newer one that uses SMR. Ooops! ).
Most of the fluff and dust in a PC is doing no harm. The exception is the fluff that gets blown down between the heatsink fins, which makes it run hotter and ultimately throttles its performance.
It got blown in so you have to suck it out. Make sure that you immobilize the fan blade with a finger, otherwise the reverse airstream from the hoover may rev your heatsink fan to destruction.
The usual hoover crevice tool is too large. I use a length of PCV oval electrical duct pushed into the crevice tool, that's narrow enough to get down between the fan blades.
I found a dead mouse once. A mammal. Inside a PC. Poor little beastie had inserted its head between an Opteron's cooling fan and the heatsink. I really hope that this broke the beastie's neck, because otherwise its death was horrible in the extreme.
I then spent ages studying the case trying to convince myself that it had any hole that a mouse could squeeze through. I couldn't. But it must have managed it somehow.
Another time I took the side off a PC and bits of dust started hopping around ... the cat had had a flea problem.
I don't know the details of AES etc, but it's a much greater class of problems than just asymmetric crypto-breaking that could in theory be tackled by a quantum computer.
Basically, N qubits can represent all numbers from 0 to 2^N-1 at once!. You then perform a series of operations on those qubits that if performed on a single number, would tell you (yes or no) that it was a member of the set of solutions smaller than 2^N-1 of your problem. For asymmetric cryptography, that search is for one of two large prime factors. You then observe your system in the quantum sense. It must collapse into one of the possible solutions of your problem - one of the two prime factors, which is all you need to break a code. For other problems there might be a known or unknown number of solutions larger than two, but provided the number of solutions is smallish, repeated runs of your quantum computer would statistically guarantee you'd find all of them ... even if knowing just one isn't all you need to get the rest conventionally.
As the number N of coupled qubits becomes large, quantum computing becomes exponentially closer to magic. That, or we discover a reason why it stops working when N is bigger than some new-physics-determined number.
The observable universe contains something of the order of (only!) 2^84 hadrons. This is why I find it inconcievable that a quantum computer could work with N qubits in the hundreds or thousands, let alone all the way up to millions, trillions and beyond. (Avogadro's number is ~10^26! )
Greg Egan writes the hardest of hard SF. For one possible implication of a working quantum computer for large N, read "Luminous"!