I assume he's referring to Orange Herald, which was a big fission bomb that was meant as a "backup" in case the actual H-bomb didn't work, so they could pretend that they'd developed the technology.
However, since the real H-bomb (Grapple X) was tested successfully less than 6 months later, it was all a bit moot.
Yes, it's been so easy to measure that it took years for anyone to realise what VW were doing... I'm afraid after VW none of these studies are really credible in any way.
People realised the basic problem for ages, they just thought it was due to the tests being unrepresentative of real-world driving - which they are, and is the correct explanation for most car manufacturers as far as we know. The studies are as valid as they ever were in terms of the effects they describe, which is that NOx from diesels in the real world is higher than the official test figures say.
Like diesels, petrols aren't nearly as 'clean' as anyone would like them to be,
No, but they're cleaner than diesel, and they're the most readily available alternative for cars. Heavy vehicles can keep using diesel with AdBlue and DPFs. Better to have a readily available "good enough" technology actually used on a big scale than a perfect one that's too expensive or otherwise problematic for widespread use.
not to mention being less efficient. They are just simply not an answer and the falling oil price scuppers it totally, no matter the propaganda.
How on earth does the falling oil price scupper anything? That will *help* the less fuel-efficient technologies, not hinder them, by reducing the cost of the inefficiency. Your statement doesn't follow.
The simple arithmetic is when you more throughly burn the fuel you get more emissions. That's the way the engine works
You're ignoring aftertreatment. It's OK to produce a pollutant if it's cleaned up before it gets into the atmosphere. Petrol catalytic converters are very efficient at removing NOx and have got ever better in recent years (diesel ones are not as the reduction reaction doesn't go in the oxygen-rich diesel exhaust). More "thoroughly burning" the fuel will, if anything, reduce emissions of hydrocarbons and carbon monoxide, as they're the products of incomplete combustion.
In any case, NOx is produced by high temperatures causing a reaction between the nitrogen and oxygen in the air. More "thorough" burning has nothing to do with it - crappy old carburetted cars produced plenty of NOx, despite having a large amount of incompletely burnt fuel in the exhaust.
and of course they're going to produce less than a diesel without a DPF, which is a downright bizarre thing to qualify that with. Remove the catalytic converter and filters and see what happens in reverse.
Not bizarre at all. DPFs don't block everything. Port-injected engines can produce less particulate matter than a diesel *with* a DPF, as can direct injection with appropriate design. It's just that that wasn't designed for until now because soot wasn't part of the petrol tests until recently (as old petrol engines produced so little of it).
In continental Europe where diesel is the same price or less expensive than petrol, which is what it should be as the fuel is cheaper to produce, the maths are quite easy to work out.
Indeed it is, and I was bored enough to do it once. The untaxed price of fuel at the moment (in the UK) is about 36p/litre vs 40p/litre for diesel (the tax is the same per litre, so the basic price of diesel is higher). For 10,000 miles a year that makes about £70 per year difference in fuel cost (diesel car getting 50mpg and petrol one about 25% less, which is typical. The difference is smaller for more modern petrols.). Nowhere near enough to justify the extra purchase cost. Even double that probably wouldn't be for most people. It's only the tax system that makes it so - why do you think diesels are far less popular outside Europe?
Hybrids are not only hellishly complex but they are incredibly expensive to maintain.
The Prius is one of the most reliable cars you can buy, so I don't know where this "incredibly expensive to maintain" comes fr
I'm afraid it does. There is an awful lot of NOx and soot that has appeared from somewhere, and the uncomfortable truth is that it isn't all down to diesel vehicles.
I'm more familiar with pollution in cities in Europe, but we've got a good idea of where the NOx comes from, as it can be measured easily from different vehicles. And those measurements show that diesels don't perform nearly as well on the road as they do in the lab (not just VW ones either), whereas the petrol ones do much better http://www.theicct.org/blogs/staff/laboratory-versus-real-world-discrepancies-nox-emissions-eu
Modern petrol/gasoline engines have essentially had to run hotter and become more like diesels to keep up with efficiency. More thorough burning of the fuel means more emissions.
The measurements show the opposite, with NOx for petrol engines going down and down. There is one area in which what you say is true - direct injection engines produce much more soot than traditional port injection ones, but still much less than a diesel without a DPF. This can probably be worked around by tuning the injection system or, worst case, adding a filter to petrol engines too (I think Mercedes has already done this on at least one model), so I don't expect it to be a problem for long.
The emissions card is all there is left to play, and that is bogus, they can never be as efficient as a diesel and trying to flog more life out of them with hybrids just makes them hideously expensive. Beyond the internal combustion engine and diesels it is electric vehicles. It's over.
Electric cars make "hideously expensive" hybrids look cheap. Combustion engines are hardly "over" - electrics account for a tiny fraction of sales. A diesel engine is also more expensive than a petrol one - if it wasn't for favourable tax rates and emissions rules in Europe they wouldn't be economic except for high mileage drivers. Efficiency isn't the be all and end all - total running costs and emissions are.
No matter how many times you post it it won't make it true. In your link, they don't even test petrol cars for soot, just assume that the discrepancy in their models is due to them. Hardly overwhelming evidence.
Presumably because gas power stations are far cleaner than coal, provide output that can be relied on (unlike wind or solar) and can be built quickly (unlike nuclear).
In the past, believing that powerful global forces were watching your every action would have been evidence of paranoia. So I'd like to commend Google for effectively treating that delusional belief by turning it into a rational fear, and thus no longer a mental illness.
Well, my life probably has about 45-50 years left, so possibly. But the current lot of EVs don't seem spectacularly better than the EV1 of the 90s. A bit better, yes, but rather less than I'd hope for nearly 20 years of development. And here's nothing obvious in line to replace the diesel engine there in big trucks or big ships, or the jet engine in aircraft. I think it's more likely than not that I'll die before the combustion engine does.
While it certainly seems unlikely to work, if it did then it would be useful to reduce the battery capacity needed on board the vehicle. Enough batteries for 300 miles of range doesn't come cheap, and is the main reason why EVs are niche vehicles for enthusiasts rather than the standard.
Background exposure is rather different to the type of exposure the workers got at the plant. Most background exposure can't even penetrate the outer layer of the skin.
In which case it's not exposure, and not counted. Background exposure can come from inhaled alpha emitters (e.g. radon), beta emitters in food, external gamma from rocks etc. It's not qualitatively different from what the workers were exposed to in terms of effects.
It's also worth pointing out that where background levels are high, much of it is often due to radiation from the sun, and that is actually quite dangerous if you get too much exposure, especially if you have white skin.
It's dangerous because of UV, which doesn't count as ionizing radiation in this context and isn't included in the "background radiation" measurements.
The exposure that the workers got involved material like caesium, which got inside the bodies and can't easily be removed. When treated for cancer it was possible to examine blood or tumours that were removed and see these particles in them, indicating the source of the DNA damage that lead to cancer.
No, all it shows is that these substances were present, not that it was the cause of the cancer. There's no way to link a specific cancer to a specific cause. You can say it's highly likely if we're talking about a cancer almost entirely caused by one thing (such as mesothelioma), but that's not the case for leukemia.
Now, it's true that there may be cancers caused by the accident in the cleanup group. But nevertheless, most cancers among those people will be unrelated to the accident, just because cancer is sadly common.
Yes, but what's the *point*? So you trick someone into destroying their computer... what does that gain you? It's not as though you can steal data or install malware that way (unless the idea is that they then throw their computer away and you "rescue" it. But that's a stretch.)
The limitation for the LHC energy is the strength of the bending magnets, and for electron synchrotrons the limit is synchrotron radiation (which increases with the fourth power of energy, so more power in won't get you much further). It's not obvious how this can improve circular accelerators.
The US doesn't even use the Imperial system, as it wasn't standardised until after the USA gained independence. So with imperial units, "a pint of water weighs a pound and a quarter", but the US saying is "a pint's a pound the whole world round" (hah!).
And then there's the mess of Troy vs avoirdupois weights. At least everyone agrees on what a kilogram is (well, the definition anyway).
Imperial/US/other traditional measures aren't more convenient for everyday living, they're just more familiar.
Yep. The B&W laser I got three years ago has been excellent. £20 refurbished from eBay, no problems with ink clogs and only on the second toner cartridge. I haven't missed colour - if I want photos printed I'll take them to the shop.
The xkcd author should stop putting his words in the mouth of a dead scientist in an attempt to give them more weight.
Without rigour, you can easily make experiments that show that homeopathy, water divining, ESP and perpetual motion machines are valid. As is most likely the case in the example of this article. An experiment without rigour is no more scientific than an anecdote.
Things like black-body emission would be very different if photons had mass. There would be a threshold energy needed to produce one, and that's not what we see. Unless you're happy to throw away the conservation of energy, in which case you might as well throw away just about all physics.
I find here in the UK the DAB stations often sound worse than their FM equivalents, thanks to an antiquated codec (MP2!). DAB+ was supposed to fix this by using AAC+, but that doesn't seem to have been deployed here. Backwards compatibility issues I guess.
Maybe according to the strict F95 standard it's not allowed, but I've done it. I think it was officially introduced in F2003 (or some TR that I forget) but compilers supported it even before then. Similarly for allocatable dummy arguments to subroutines.
Not to say there aren't some weird quirks with Fortran arrays, like how if you pass an allocatable array to a subroutine where the dummy argument is not allocatable then it *must* be allocated, even if the subroutine isn't going to touch it.
It's a hardware thing -- the memory bus and memory read/write speeds are still a limiting factors, particularly as CPU cores get faster and more efficient.
Oh yes, I've seen plenty of code that's limited by memory bandwidth. But I don't think that's what's going on here - simply deallocating and reallocating shouldn't actually touch all of the memory in question, should it?
Fortunately for that kind of code, avoiding such reallocations isn't difficult.
Does it still win with dynamic memory allocation? How granular is the dynamic memory allocation? Complete like C?
Fortran's dynamic memory allocation is much easier to work with than C's. You simply declare a variable allocatable, then allocate as needed with the appropriate size. It automatically gets deallocated when it falls out of scope, so no memory leaks (at least since F95).
e.g.
real, allocatable:: myarray(:)
allocate (myarray(1000), stat=ierr) (something to check error code ierr here)
I've written a bit of finite difference code in Fortran. Repeatedly allocating and deallocating can give a huge performance hit, so I tend to do all my allocations before the main loop. Not entirely sure why the penalty is so big, but it seems to be - these are allocations of hundreds of MB or even a few GB, so the cost of operations done on the arrays should dwarf the cost of the allocation. Unless there's some underlying reason why touching newly allocated memory is so slow, but I don't know enough about how virtual memory behaves to say.
If end user hardware doesn't support it or isn't configured properly, then they will be completely unaware of and unaffected by its existence.
End user hardware generally does support it though - any vaguely modern computer, smartphone or tablet should automatically pick up and use an IPv6 address if available. So if the ISPs start supplying v6 it's essential that it works reliably, because the users' devices will try and use it. Broken v6 does affect connectivity, even if v4 still works fine. And even if the fault is with the users own equipment, you can bet they'll be complaining to the ISP.
Second post because I realised my first one doesn't directly address your point above.
That should be true in theory, but the IPv6 hardware & software is nowhere near as well tested as the IPv4 equivalent, both in terms of home equipment and in the ISPs own networks. How often does this kind of thing work perfectly first time? And the staff don't have the same experience with it to fix problems when they do occur. Anything new is a risk, and since hardly any home customers are demanding IPv6 it might seem like it's a risk not worth taking until made absolutely necessary by v4 exhaustion.
That's not what *I* want, but from an ISP's perspective I can see how it would make sense to prepare & test their network for v6 steadily, slowly and thoroughly but not actually deploy it while they still have enough v4 addresses.
I assume that's for the US, which seems ahead of the game despite having plenty of v4 addresses.
Here in the UK, none of the major ISPs have deployed v6 at all, and I don't think any of the mobile companies have either. I suppose they're just risk averse, as dealing with support calls for unexpected problems isn't cheap and their margins aren't huge.
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Not all at once they don't. Variability in a fleet of nuclear plants is far lower than in a fleet of wind turbines of the same capacity.
I assume he's referring to Orange Herald, which was a big fission bomb that was meant as a "backup" in case the actual H-bomb didn't work, so they could pretend that they'd developed the technology.
However, since the real H-bomb (Grapple X) was tested successfully less than 6 months later, it was all a bit moot.
Yes, it's been so easy to measure that it took years for anyone to realise what VW were doing... I'm afraid after VW none of these studies are really credible in any way.
People realised the basic problem for ages, they just thought it was due to the tests being unrepresentative of real-world driving - which they are, and is the correct explanation for most car manufacturers as far as we know. The studies are as valid as they ever were in terms of the effects they describe, which is that NOx from diesels in the real world is higher than the official test figures say.
Like diesels, petrols aren't nearly as 'clean' as anyone would like them to be,
No, but they're cleaner than diesel, and they're the most readily available alternative for cars. Heavy vehicles can keep using diesel with AdBlue and DPFs. Better to have a readily available "good enough" technology actually used on a big scale than a perfect one that's too expensive or otherwise problematic for widespread use.
not to mention being less efficient. They are just simply not an answer and the falling oil price scuppers it totally, no matter the propaganda.
How on earth does the falling oil price scupper anything? That will *help* the less fuel-efficient technologies, not hinder them, by reducing the cost of the inefficiency. Your statement doesn't follow.
The simple arithmetic is when you more throughly burn the fuel you get more emissions. That's the way the engine works
You're ignoring aftertreatment. It's OK to produce a pollutant if it's cleaned up before it gets into the atmosphere. Petrol catalytic converters are very efficient at removing NOx and have got ever better in recent years (diesel ones are not as the reduction reaction doesn't go in the oxygen-rich diesel exhaust). More "thoroughly burning" the fuel will, if anything, reduce emissions of hydrocarbons and carbon monoxide, as they're the products of incomplete combustion.
In any case, NOx is produced by high temperatures causing a reaction between the nitrogen and oxygen in the air. More "thorough" burning has nothing to do with it - crappy old carburetted cars produced plenty of NOx, despite having a large amount of incompletely burnt fuel in the exhaust.
and of course they're going to produce less than a diesel without a DPF, which is a downright bizarre thing to qualify that with. Remove the catalytic converter and filters and see what happens in reverse.
Not bizarre at all. DPFs don't block everything. Port-injected engines can produce less particulate matter than a diesel *with* a DPF, as can direct injection with appropriate design. It's just that that wasn't designed for until now because soot wasn't part of the petrol tests until recently (as old petrol engines produced so little of it).
In continental Europe where diesel is the same price or less expensive than petrol, which is what it should be as the fuel is cheaper to produce, the maths are quite easy to work out.
Indeed it is, and I was bored enough to do it once. The untaxed price of fuel at the moment (in the UK) is about 36p/litre vs 40p/litre for diesel (the tax is the same per litre, so the basic price of diesel is higher). For 10,000 miles a year that makes about £70 per year difference in fuel cost (diesel car getting 50mpg and petrol one about 25% less, which is typical. The difference is smaller for more modern petrols.). Nowhere near enough to justify the extra purchase cost. Even double that probably wouldn't be for most people. It's only the tax system that makes it so - why do you think diesels are far less popular outside Europe?
Hybrids are not only hellishly complex but they are incredibly expensive to maintain.
The Prius is one of the most reliable cars you can buy, so I don't know where this "incredibly expensive to maintain" comes fr
I'm afraid it does. There is an awful lot of NOx and soot that has appeared from somewhere, and the uncomfortable truth is that it isn't all down to diesel vehicles.
I'm more familiar with pollution in cities in Europe, but we've got a good idea of where the NOx comes from, as it can be measured easily from different vehicles. And those measurements show that diesels don't perform nearly as well on the road as they do in the lab (not just VW ones either), whereas the petrol ones do much better http://www.theicct.org/blogs/staff/laboratory-versus-real-world-discrepancies-nox-emissions-eu
Modern petrol/gasoline engines have essentially had to run hotter and become more like diesels to keep up with efficiency. More thorough burning of the fuel means more emissions.
The measurements show the opposite, with NOx for petrol engines going down and down. There is one area in which what you say is true - direct injection engines produce much more soot than traditional port injection ones, but still much less than a diesel without a DPF. This can probably be worked around by tuning the injection system or, worst case, adding a filter to petrol engines too (I think Mercedes has already done this on at least one model), so I don't expect it to be a problem for long.
The emissions card is all there is left to play, and that is bogus, they can never be as efficient as a diesel and trying to flog more life out of them with hybrids just makes them hideously expensive. Beyond the internal combustion engine and diesels it is electric vehicles. It's over.
Electric cars make "hideously expensive" hybrids look cheap. Combustion engines are hardly "over" - electrics account for a tiny fraction of sales. A diesel engine is also more expensive than a petrol one - if it wasn't for favourable tax rates and emissions rules in Europe they wouldn't be economic except for high mileage drivers. Efficiency isn't the be all and end all - total running costs and emissions are.
No matter how many times you post it it won't make it true. In your link, they don't even test petrol cars for soot, just assume that the discrepancy in their models is due to them. Hardly overwhelming evidence.
I'm left wondering why the fuck they want gas.
Presumably because gas power stations are far cleaner than coal, provide output that can be relied on (unlike wind or solar) and can be built quickly (unlike nuclear).
They do - at least the ones I see around here.
And occasionally I see black smoke from diesel cars that should be new enough to have a DPF. Not sure what's going on there.
In the past, believing that powerful global forces were watching your every action would have been evidence of paranoia. So I'd like to commend Google for effectively treating that delusional belief by turning it into a rational fear, and thus no longer a mental illness.
Well, my life probably has about 45-50 years left, so possibly. But the current lot of EVs don't seem spectacularly better than the EV1 of the 90s. A bit better, yes, but rather less than I'd hope for nearly 20 years of development. And here's nothing obvious in line to replace the diesel engine there in big trucks or big ships, or the jet engine in aircraft. I think it's more likely than not that I'll die before the combustion engine does.
While it certainly seems unlikely to work, if it did then it would be useful to reduce the battery capacity needed on board the vehicle. Enough batteries for 300 miles of range doesn't come cheap, and is the main reason why EVs are niche vehicles for enthusiasts rather than the standard.
Background exposure is rather different to the type of exposure the workers got at the plant. Most background exposure can't even penetrate the outer layer of the skin.
In which case it's not exposure, and not counted. Background exposure can come from inhaled alpha emitters (e.g. radon), beta emitters in food, external gamma from rocks etc. It's not qualitatively different from what the workers were exposed to in terms of effects.
It's also worth pointing out that where background levels are high, much of it is often due to radiation from the sun, and that is actually quite dangerous if you get too much exposure, especially if you have white skin.
It's dangerous because of UV, which doesn't count as ionizing radiation in this context and isn't included in the "background radiation" measurements.
The exposure that the workers got involved material like caesium, which got inside the bodies and can't easily be removed. When treated for cancer it was possible to examine blood or tumours that were removed and see these particles in them, indicating the source of the DNA damage that lead to cancer.
No, all it shows is that these substances were present, not that it was the cause of the cancer. There's no way to link a specific cancer to a specific cause. You can say it's highly likely if we're talking about a cancer almost entirely caused by one thing (such as mesothelioma), but that's not the case for leukemia.
Now, it's true that there may be cancers caused by the accident in the cleanup group. But nevertheless, most cancers among those people will be unrelated to the accident, just because cancer is sadly common.
Yes, but what's the *point*? So you trick someone into destroying their computer... what does that gain you? It's not as though you can steal data or install malware that way (unless the idea is that they then throw their computer away and you "rescue" it. But that's a stretch.)
The limitation for the LHC energy is the strength of the bending magnets, and for electron synchrotrons the limit is synchrotron radiation (which increases with the fourth power of energy, so more power in won't get you much further). It's not obvious how this can improve circular accelerators.
The US doesn't even use the Imperial system, as it wasn't standardised until after the USA gained independence. So with imperial units, "a pint of water weighs a pound and a quarter", but the US saying is "a pint's a pound the whole world round" (hah!).
And then there's the mess of Troy vs avoirdupois weights. At least everyone agrees on what a kilogram is (well, the definition anyway).
Imperial/US/other traditional measures aren't more convenient for everyday living, they're just more familiar.
Yep. The B&W laser I got three years ago has been excellent. £20 refurbished from eBay, no problems with ink clogs and only on the second toner cartridge. I haven't missed colour - if I want photos printed I'll take them to the shop.
Actually, Sky aren't offering any IPv6 yet, except to a small trial.
But for the trial customers, they're handing out /56s.
The xkcd author should stop putting his words in the mouth of a dead scientist in an attempt to give them more weight.
Without rigour, you can easily make experiments that show that homeopathy, water divining, ESP and perpetual motion machines are valid. As is most likely the case in the example of this article. An experiment without rigour is no more scientific than an anecdote.
Things like black-body emission would be very different if photons had mass. There would be a threshold energy needed to produce one, and that's not what we see. Unless you're happy to throw away the conservation of energy, in which case you might as well throw away just about all physics.
I find here in the UK the DAB stations often sound worse than their FM equivalents, thanks to an antiquated codec (MP2!). DAB+ was supposed to fix this by using AAC+, but that doesn't seem to have been deployed here. Backwards compatibility issues I guess.
Maybe according to the strict F95 standard it's not allowed, but I've done it. I think it was officially introduced in F2003 (or some TR that I forget) but compilers supported it even before then. Similarly for allocatable dummy arguments to subroutines.
Not to say there aren't some weird quirks with Fortran arrays, like how if you pass an allocatable array to a subroutine where the dummy argument is not allocatable then it *must* be allocated, even if the subroutine isn't going to touch it.
It's a hardware thing -- the memory bus and memory read/write speeds are still a limiting factors, particularly as CPU cores get faster and more efficient.
Oh yes, I've seen plenty of code that's limited by memory bandwidth. But I don't think that's what's going on here - simply deallocating and reallocating shouldn't actually touch all of the memory in question, should it?
Fortunately for that kind of code, avoiding such reallocations isn't difficult.
Does it still win with dynamic memory allocation? How granular is the dynamic memory allocation? Complete like C?
Fortran's dynamic memory allocation is much easier to work with than C's. You simply declare a variable allocatable, then allocate as needed with the appropriate size. It automatically gets deallocated when it falls out of scope, so no memory leaks (at least since F95).
e.g.
real, allocatable :: myarray(:)
allocate (myarray(1000), stat=ierr)
(something to check error code ierr here)
I've written a bit of finite difference code in Fortran. Repeatedly allocating and deallocating can give a huge performance hit, so I tend to do all my allocations before the main loop. Not entirely sure why the penalty is so big, but it seems to be - these are allocations of hundreds of MB or even a few GB, so the cost of operations done on the arrays should dwarf the cost of the allocation. Unless there's some underlying reason why touching newly allocated memory is so slow, but I don't know enough about how virtual memory behaves to say.
If end user hardware doesn't support it or isn't configured properly, then they will be completely unaware of and unaffected by its existence.
End user hardware generally does support it though - any vaguely modern computer, smartphone or tablet should automatically pick up and use an IPv6 address if available. So if the ISPs start supplying v6 it's essential that it works reliably, because the users' devices will try and use it. Broken v6 does affect connectivity, even if v4 still works fine. And even if the fault is with the users own equipment, you can bet they'll be complaining to the ISP.
Second post because I realised my first one doesn't directly address your point above.
That should be true in theory, but the IPv6 hardware & software is nowhere near as well tested as the IPv4 equivalent, both in terms of home equipment and in the ISPs own networks. How often does this kind of thing work perfectly first time? And the staff don't have the same experience with it to fix problems when they do occur. Anything new is a risk, and since hardly any home customers are demanding IPv6 it might seem like it's a risk not worth taking until made absolutely necessary by v4 exhaustion.
That's not what *I* want, but from an ISP's perspective I can see how it would make sense to prepare & test their network for v6 steadily, slowly and thoroughly but not actually deploy it while they still have enough v4 addresses.
I assume that's for the US, which seems ahead of the game despite having plenty of v4 addresses.
Here in the UK, none of the major ISPs have deployed v6 at all, and I don't think any of the mobile companies have either. I suppose they're just risk averse, as dealing with support calls for unexpected problems isn't cheap and their margins aren't huge.