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Comment Re:Err, petrol is currently cheaper that diesel (Score 1) 182

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 from. Hellishly complicated? You're just replacing a starter, alternator, and complicated conventional transmission with two motor-generators, a NiMh or Li-ion battery and a simpler transmission (look it up, it's really quite elegant). More expensive, certainly, as the motors have to be much more powerful, but not really more complicated.

They're certainly more expensive than a diesel engine. Electric vehicles have far fewer moving parts and simply don't need the oils and lubricants a modern combustion engine does.

True, but the capital cost of the batteries is vastly greater than the cost of a few litres of lubricant oil every year. And all the non-engine parts will need maintenance just the same.

It's a question of where the future is if people really care about emissions and want something that is efficient whilst being cheap enough to buy

But they're not cheap enough to buy yet, that's the point. Maybe they will be one day, maybe not.

and especially maintain and there really isn't any more efficiency to be hammered out of the internal combustion engine. The best you can ever hope for in terms of efficiency for a combustion engine is 40% (being very optimistic) - and that's with a turbo, energy recovery systems and every piece of expensive technology you can throw at it. It really is over.

Diesel engines can already do better than 40% - and old diesels too, without all the complicated stuff. The pretty standard engine in the Prius can do high 30s. But again, why does a modest efficiency mean "it's over"? 25% is good enough if the fuel's cheap enough that the total cost of ownership is lower than the more efficient alternatives. And so far that's still the case - despite the huge taxes on fuel in Europe.

If it's complexity you're bothered about then I don't know how you can support the diesel engine. Modern diesels are hellishly complicated - turbochargers, DPFs, urea systems (in some cases), ultra high pressure injectors machined to insane tolerances. The old ones may have been simple, but not the ones you can buy today.

Once you start using heaters and air conditioning systems in a car the comparisons get even more unfavourable when it comes to petrols

That doesn't make sense, heaters use free waste heat (of which there's more with a petrol engine due to the lower thermal efficiency) and aircon is just an extra load on the engine, and will affect petrol and diesel similarly.

Comment Re:Err, petrol is currently cheaper that diesel (Score 1) 182

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

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.

Comment Re:What an incredibly stupid idea... (Score 1) 77

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.

Comment Re:What an incredibly stupid idea... (Score 1) 77

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.

Comment Re:Criteria from TFA (Score 1) 138

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.

Comment Re:Home depot sells similar devices (Score 1) 229

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.)

Comment Re:My ever shrinking HADRON (Score 3, Insightful) 52

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.

Comment Re:The kilogram is based on a chunk of metal? (Score 1) 278

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.

Comment Re:Ooh Oopsie (Score 1) 518

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.

Pound for pound, the amoeba is the most vicious animal on earth.