Posts by Phil

Gov launches 'Healthy Bees' plan

invest...

Perhaps they might want to invest a bit in actually supporting beekeepers. Last I heard the guy who is bee inspector for virtually the whole of south east England (as far west as Dorset, and north as Oxford...) is retiring, and they are trying to find a replacement willing to work for a pitiful £24K. That's for a full-time job, including running evening classes and training sessions for beekeepers across the entire region, as well as actually inspecting people's hives and trying to stop the spread of bee diseases and parasites.

As for science, well, the UK used to lead that field, but due to years of little to no interest/investment, I doubt there are that many dedicated bee researchers left...

Its interesting how something so important (the fertilisation of plants, thus our entire food chain) is deemed unimportant enough that the only reason it exists at all is due to the dedication of hobbyists and amateurs.

PS: nice to see that at least beekeeping is getting some publicity.

Has your shifty foreign neighbour got 16 mobes?

glad I got out

I was browsing at work (no firefox/adblock) the other day when I spotted the advert about terrorists using masks and gloves, so anyone using such should be reported asap.

I'm pretty sure I was so surprised I exclaimed out loud, my instant reaction was are they serious, can they not see this is pretty much straight out of 1984. Now I see its part of a wider campaign, all of which seems pretty much in the vein of 'is your partner/parent/sibling/child/friend thinking bad things about the state? Report them quick, and we will come round in the middle of the night and take them away for you, and make sure they confess all'.

The more I read about the state of affairs in England, the more glad I am I got out. You seem to be sleepwalking into a police surveillance state, and everyone is too polite/scared to comment or complain...

At this rate, I don't think I will be going back. Next Christmas, my family can come to me (if people can still travel by then without being arrested as potential terrorists - travelling abroad, must be up to something...).

God help you all...

Postmaster kills off 'free for life' webmail

re: no ads?

If you want no ads, just firefox as your browser, and install the Adblock app. Works for me.

140mph YouTube boy racer facing jail

Madness...

The guy is an accident waiting to happen. Not only driving like a prick, at twice the speed limit, all over the road, in busy traffic, but doing it all with one hand while recording his retardedness on his phone for posterity/the police. Frankly, I'm extremely surprised that little stunt didn't end in a serious crash.

Incidentally, anyone else notice the dark green (VW?) near the start of the clip. It must have been going a good 100mph, according to our star's speedo...

Cars could run on aluminium, say US boffins

Title

Quote: "Erm... No big tanks of water required...

new pellets + water = Hydrogen and old pellets

Hydrogen + oxygen = water and vroom.

take the exhaust water and add it back to start again."

Its not quite that simple. There are two separate reactions happening. First you are liberating hydrogen from the water using aluminium.

2Al + 6H2O --> 2Al(OH)3 + 3H2 (subscript is also missing from these boards...)

Notice 6 water molecules give only 3 hydrogen molecules (6 hydrogen atoms). All 6 oxygens and the other 6 hydrogens are locked up in the aluminium hydroxide (and thus are not available for 'recycling').

In the engine an entirely seperate reaction takes place.

3H2 + 1.5O2 --> 3H2O

The oxygen in this reaction comes from the air, and is totally separate from the oxygen that the hydrogen was originally bonded to. That oxygen is now part of the aluminium hydroxide.

We could collect our new water and use that to react with more aluminium pellets. In fact we would produce 175Kg of water this way (19.4kg of hydrogen burns to make 175Kg of water - the extra 155.6Kg coming from the mass of oxygen taken from the air), so we would only need to start out with 175Kg. We would still end up with 525Kg of aluminium hydroxide, so our car would end up carrying more mass than when it started.

edit

also recycling the water would actually increase the mass of the car as you drive. You would be adding the mass of the oxygen from the air used to burn the hydrogen in the engine.

This lack of edit function is really annoying...

Re: Weight of water

You cant just recycle the water. Yes, you could use the water you make to supplement the on-board store, but since out of every water molecule, only one hydrogen atom goes to make hydrogen gas. The oxygen and the other hydrogen react with the aluminium to make aluminium hydroxide. Hence you would need at least half the total mass of water you need. I effectively ignored the combustion side of the reaction in my earlier post, as the oxygen needed and the waste water produced both dont affect the mass of the car (coming from and returning to the atmosphere).

Ishkandar: I dont live in London, but this neednt be a problem. At least no more of a problem than storing hydrogen in the car. The whole point of the hydrogen generator is that you generate hydrogen when you need it, otherwise you might as well use the electricity to electrolyse water in the first place, and not the aluminium ore, and deliver hydrogen gas direct to the customer. Its far more efficient that way.

In my experience hydrogen liberation by adding metal to acid (or water, if the metal is reactive enough) is a pretty quick affair. You wouldnt need to limit the rate, so could just chuck a load of pellets into the generator shortly before you go, and bingo, you're tank will soon be full... (the reaction is very fast at the start as there are lots of unreacted particles of metal and water mixed together, so the chance of them meeting and reacting is initially very high).

To the diesel car owner: The reason you cant run your car on diesel is because you would not be paying fuel tax, and our dear (soon to be leader) chancellor takes a dim view of people sidestepping his money harvesting schemes... Theres no reason why you cant do it on the sly, except that your car smells like a chippy when you are driving along...

RE: Other elements that might work?

Tom:

Sodium cannot easily be extracted from sea water. Simply evapourating the water will leave you with salt, which is useless for this purpose.

Electrolysis of seawater will produce sodium hydroxide, which is not much use here either.

Electrolysis of molten NaCl (salt) will produce pure sodium, but what then. The stuff is very reactive, oxidises damn fast, and is generally pretty unpleasant.

Anyway, as electrolysis is the same process that is used to extract aluminium, it makes no sense to use sodium, as the cost increases to get the more reactive metal.

Aluminium is a good choice, as it is so abundant. It is unfortunately very hard to extract, hence why it isnt cheap.

Zinc is anther option, and is certainly easier to get, as you can extract it by a displacement reaction using carbon. This eliminates the need for costly electricity, but does mean you start producing nasty polluting gases like carbon dioxide and sulphur dioxide (depending on the zinc ore used). The resulting slower rate of reaction in the hydrogen generator could be improved by acidifying the water (perhaps using the nasty polluting gases. Now theres an idea...)

Edit: Rate of Reation

Of course the most effective solution would be to use your 525Kg to install a decent hydrogen containment system. You would be able to carry much more than 19.4Kg, thus giving you a far greater fuel economy than petrol. Perhaps the hydrogen generator could be a stationary device, in refueling (petrol) stations, or even in people's garages. You just use them to fill up your car at home, and the mass of other products doesnt matter much, as you simply get it collected and recycled when you get another load of fuel pellets delivered...

PS: Why isnt there an edit function on these boards?

Rate of reaction?

How do they get the stuff to react fast enough to produce the neccessary volume of hydrogen? Even dropping bits of aluminium in acid doesnt do much more than bubble gently, due to aluminium's inconvenient oxide layer. You would need to optimise the surface area of the fuel pellets, which would mean costly machining of a resource which is going to be ultimately destroyed. You then need to manage the rate to ensure it continues to produce hydrogen fast enough to supply demand, but not so fast that an excess builds up, while having potential to supply more when needed, like when you need to climb a hill. Thats going to be some fiddly mechanics quite seperate from the engine, adding to the mass of the car.

Its also not that efficient in terms of mass of fuel to energy output. You carry 175kg of Al, and 350Kg of water to react with it, and produce 505.6Kg of Al(OH)3 and a measly 19.4kg of Hydrogen...

Whereas every gram of petrol carried is burned, at once releasing its stored energy, and reducing the mass of the car as the waste products are both gases, the hydrogen generator only release energy from the hydrogen produced. The Aluminium hydroxide is just additional, useless mass.

19.4kg of Hydrogen will release 7.8 x10^6 kJ of energy.

525Kg of Octane will release 2.5 x 10^7 kJ of energy, and you wont be carting round 95% of the original mass... Not really a contest.

Dont get me wrong, I think the idea has potential, but a portable hydrogen generator is not as convenient as it sounds, otherwise it would have already been adopted. The chemistry behind it is nothing new.

The Pirate Bay launches music sharing site

Survival of the fittest?

"P2P networks have succumbed one by one since the US Supreme Court ruled in June 2005 that file sharing services are illegal. "

Bittorrent, which I have to say is my P2P medium of choice, appears to be surviving pretty well...

All that is achieved by bringing down one network is shifting its users to another. And as the easy targets are taken down, the harder ones will remain. The music lobby is fighting a losing battle, somewhat akin to the prohibitionists. People will find ways of getting what they want, the way they want it.

As much as they may spend time and resources trying to destroy it, there are more people, and probably more talented people willing to advance P2P technology. One day, 'untraceable' P2P may be a reality, and then the music industry is really up the creek...