insane_alien

i'd say its possible. the chemical vapour depostion method should definitely be achievable in the domestic scale. and you'll get high quality and possibly large diamonds out of it. i might try it when i get the time.

because its an interesting reaction pathway and is a pretty common one. what more is needed other than the desire? To jordehwa, you cannot just bubble sulphur dioxide through water to make sulphuric acid, you will make sulphurous acid but not sulphuric acid. To make sulphuric acid you first need to convert the SO2 into SO3. this can be done by reacting SO2 with O2 in the presence of a V2O5 catalyst. There are various ways to get the SO3 to H2SO4, you can either bubble it through already concentrated sulphuric acid to form oleum and then add more water to break it down or you can hydrate it in the vapour phase and then condense it. Alternatively, you could bubble the SO2 through hydrogen peroxide. although i don't think the yeild is as good on that and it will have a sulphurous acid impurity.

cough, Au not AU. big difference.

actually the oceans are pretty calm at the depths proposed for the tunnel. it would be anchored not much different to how floating oil rigs are and they are remarkably stable even in severe weather. any sway woul be on a large enough scale that it would not be noticable and easily handled by the lateral guiding magnets a tunnel on the sea bed would be a terrible idea. for one it would have to withstand MASSIVE pressure differences, about 450 bar. that would make it pretty costly. even some pretty advanced submarines cannot get that deep. The electromagnets would have to go for the full extent of the track, you need magnets to levitate your superconductor(a track of superconductor wouldn't work so well and would be orders of magnitude more expensive to install and maintain). with a vacuum tunnel on land, you biggest problems are where it is running(not so much a problem if it is buried or elevated) through. it'll likely disrupt the local migration patterns of animals. and another one is accidents or even the remote possibility of a deliberate attack. it wouldn't take much to flood the tunnel with atmosphere which could potentially destroy a train if it hits the gas when travelling at high speed. another problem of land based track is that the tunnel should be kept very very straight with only slight curves for corners to enable the trains to go as fast as possible. this is much harder to do on land and would likely increase costs a fair bit.

was it a popular science book? because the people who write those, while they may know their stuff in the real world, dumb it down a bit for general consumption. as is inevitable, many things are lost in the translation and it becomes easy to misinterpret.

this is a good idea, you'll also see how they deal with other problems not mentioned yet. the vacuum itself does not have temperature but objects in it do and they will be giving off thermal radiation which will be the main method of heat transfer between the train and the walls. while there isn't enough information for an exact answer right now, it shouldn't be too bad as long as the supports as sufficiently thermally insulated. liquid nitrogen isn't so expensive and we have superconductors that can operate in that sort of range. permanent magnets of the strength and quantity needed would be very very expensive and likely take decades to manufacture and use up our supplies of neodynium(its not called a rare-earth metal for nothing). electromagnets are cheap and you only have to turn on the sections of track being used at that time. The inductrack will cause magnetic drag slowing the train down if there isn't active propulsion being used. and as it gets slower the drag will increase. so it isn't without its problems.

probably, but everytime i've used it from a hardware store its been pretty obvious that soemthing else was in it. either the solution turning brown and once even a chlorine smell when the other reactants didn't contain anything like chlorine.

because lye bought from the hardware store is rarely purely a sodium hydroxide solution.

First off, thanks for the refreshing change. Most newbies around here throw a hissy fit when the realise people aren't bowing down and worshipping at their feet when the present an idea they've had. You realise its got its flaws and that they can be fixed and you are willing to fix them. This is the right attitude, this will lead to interesting discussions that actually move forward and make your ideas better as well as allowing you to learn more. once again, Thank you! Yep, i was trying to limit the problems to showstoppers rather than detail bugs which should be left to the final stages of design. The problem with magnets is that they have two poles whether they are permanent magnets or electromagnets. It is exceedingly difficult to keep an object levitated by them stable as it'll want to flip over and get closer. It's possible, but it would be difficult. with a super conductor, all you need to do is clamp it in place while the magnets are off, turn on the magnets, wait till they reach full strength and then release the clamp and its done. it won't flip it won't fall and its simply done. Well the automated gas release is a step in the right direction. much safer than leaving it up to the traveller who, unless there is some sort of vacuum tube license scheme going around, may never have been in one. as for the slamming into the wall, i meant the end of the tube. motion in a vacuum is counterintuitive to humans as we are familiar with friction and not familiar with no friction. if you leave it too late to start releasing gas in the other direction then you could hit the end of the tube at high speed. with an automated system this is countered is suppose. the trains, while more expensive per unit would require a lot less units than individual suits. plus, there are existing technologies widely used that could work as a train. modifying an airliner hull to make it airtight and fitting a magnet system would do it. And in keeping with the aircraft, there is a reason they don't just give you a private plane when you go to take off. it would require more units, more fuel and less profit. If they can bang you all in the one with limited legroom, PROFIT! with your system, the cost of the things travelling down it is going to depend on the surface area that needs to be vacuum tight. so, we have two situations small one man vessels or multi man trains. for the sake of arguement and simple maths, we will assume that they are cubes(although this applies to any shape. The volume of a cube is l^3 where l is the length of one side. the area of a cube is 6l^2. as volume is what would allow you to carry more people and surface area is what increases your costs, we'll divide the surface area by the volume. 6l^2/l^3 = 6/l this shows us we have a non-linear relationship between cost per person and size. as l gets bigger, the cost per passenger gets smaller. a two person carrier will approximately half your costs, a four person carrier would quarter them etc. this is what i was driving at. it also means congestion. a regular train service would be able to carry more people as they'd be closer together. it also means there is more room for error. one every five seconds is fine for a flume(i am informed that these are called waterslides in the US) but not for a transportaion system. to carry on the flume analogy, there is always the tubby kid that gets stuck. in any major system you WILL have breakdowns and mistakes. It could be a stuck valve, or maybe someone didn't fill up the tanks right but eventually one won't make it up to full velocity and the next person is going to slam into them at quite a high speed. you don't need to expend any energy after you have accelerated with a maglev either. well, appart from the electro magnets to allow levitation which you'll have as well, permanent magnets just aren't strong enough. the reason a maglev needs to keep expending energy is because of air resistance. but remember, we don't have any air resistance here so the maglev only needs to expend energy when it is accelerating just like your system releasing a gas to accelerate. yes, you'll need vacuum pumps to maintain the vacuum(pipes are leaky, you'll never get a vacuum that'll last.) but you won't recapture all the gas in any reasonable amount of time. most of it will expand up the tube with the traveller. you'd maybe get 10% of it back in time for the next guy. but getting all of it would take weeks. Even without releasing gas for propulsion, you would still need pumping stations every few kilometers just to maintain an even and good vacuum. with the propulsion gasses you're going to need a lot more of them to maintain a good enough vacuum. well, ideally your magnetic levitation system would counter that (otherwise you get the pinned to the floor situation). but other than that, use a stabiliserthat sticks out the front and back and is repelled by the magnets like the anti-roll bars you get on dragracers and so on. a train wouldn't need those as it has a long length anyway that would provide stability. once again, thanks for being a rational human being

which will be chock full of impurities

this isn't frame dragging at all. well, it will play a SMALL part but at the velocities and masses involved the effect will be immeasurable, heck, we're struggling to detect it for the earth. we had to build 4 of the smoothest balls ever made and some of the most precise machinery ever made to get a measurement. the answer to both hose questions is centripetal acceleration.

well, this idea has already been thought of, and to an extent implemented although not for human transport. so to your questions: 1/ An airlock works by having two doors. only one of which can be open at one time. You go in one door in your space suit, close the door and then all the air is sucked out by a vacuum pump, this will take a few minutes. then, when there is a vacuum, the other door will open and you can step through. to exit the vaccuum chamber you just need to do the reverse. 2/ well you could point the gas cylinder in the opposite direction other than that some form of friction brake but really you don't want to be going down this thing in a suit rather a vehicle like a train which is what most ideas propose. 3/ yeah, there are a nuumber of problems with your idea and i'll warn you now, i'm going to go through the major ones and if you don't want to hear it then stop reading now. a) normal magnets are hard to align so you have a stable field where an object can just sit there happily. what'll most likely happen when the guy gets in is that he flips over and gets pinned to the floor. The usual way around this problem is the use of superconductors in a magnetic field as they can remain stable. b) you're leaving this up to the person inside who may be Mr S. Tupid, someone is going to mess it up and SPLAT! much better to have a train arrangement with a designated driver. c) you could only transport one person at a time with the method you propose, a train could carry many people at the same time d) your propulsion system is no good without a vast number of vaccuum pumps along the 'track' as otherwise the vacuum would be filled with spent fuel gas. you are already going to the trouble of building a magnetic track, why not just use magnetic propulsion too. you'll be able to go faster, able to stop quicker, won't have to carry propellant and you won't be destroying the vacuum. it is an interesting idea and most people who think about it go for a more massive scale. some have even drawn up plans (feasible, could be put into action tomorrow plans) for such a train/tunnel system to cross the atlantic ocean. The big barriers for this are cost and that there are no known room temperature superconductors. EDIT: whoops, lopped part of my post off by accident Yeah, so keep thinking about this, it's an awesome idea and i'd love to take a trip on a vacuum train but also think more about safety, reliability, costs and so on. not only will this allow you to come up with better ideas, but it could also net you a bit of cash on the side if you're lucky.

no, you don't have us stumped, it is just that nobody can be bothered arguing with you anymore as you don't seem to understand what is being said.

hunting them down may actually be morally superior to leaving them be. to leave them roaming free increases the risk of secondary outbreaks resulting in more deaths. with the lack of any known or suspected cure or facilities to capture and restrain the infected, elimination may be the best option. of course, by this time it will likely be known whether there is any irreversable component of the disease(ie, brain damage) which should simplify the moral choice a lot.

i'd say it is when containment is lost. and by containment, I mean when the infected are no longer being restrained effectively. this could apply to many situations, 1/ if an infected gets loose in the ambulance, okay for the paramedics to permanently disable the threat. 2/ if one or more infected get loose in a hospital 3/ if the infected are on the streets. particularly if there are uninfected around. 4/ when the emergency services can no longer secure any more of them due to high numbers. its unsavoury, but the other result is in massive spread of infection and ultimately the death of many millions more.

the atoms in a molecule are jiggling about. if you fire photons at it that match this frequency of jiggling then they are more likely to be absorbed. it is important to note that this has nothing at all to do with new agers and crystals and all that rubbish.

probably not. wolfram alpha is a stripped down version of mathematica. and the fact the have to run it on their servers probably means they don't want people doing intensive calculations(which is what happens when you use high precision maths.

supersoaker, plus petrol, plus lighter. not easy to buy premade, but damn easy to cobble together in short order. and lets face it, most weapons will be improvised at some point during the crisis.

it doesn't have to be rabies. just a disease that produces symptoms similar to those seen in zombie flicks. look up 28days later, that sort of thing.

who gives a crap about inflicting pain, it'll still take a zombie down and more, it will cremate the body enough to render it sterile. ofcourse, this weapon should not be used to stand off zombies, but if you're doing that then you're being an idiot. you want to be mobile since mobility tends to be a weakness of most zombies.

what do you mean by 'no temperature' this is a nonsensical phrase as everthing has temperature(well, except perhaps a vacuum). so, do you know what the relative humidity in the CO2 is? if it is 0% then the droplet WILL evapourate quickly at a raised temperature. in the phase diagram, you seem to be confusing system pressure and partial pressure of water vapour in the system. if you want to prevent the droplet from evapourating then you need a partial pressure of water of about 6 bar in the system to get the droplet to remain there.

actually shot guns would be bad in a zombie outbreak. in most if not all zombie literature, you can become infected via contact with bodily fluids, ie blood. a shotgun blast to the undead cranium will splatter blood everywhere, front and back, as well as a fair amount of aerosolized blood that could still potentially carry the virus. this means whoever was near the zombie, and very likely the shooter him/herself would be infected if not properly protected against such an effect. a much better weapon would be a flamethrower, sterilizes any droplets that may come off the zombie.

1 000 000 grams per tonne.

/me sticks his toungue out at capn na na na na na! this is why i always ask engineers about math questions rather than mathematicians. engineers understand the concept of 'close enough' and what 'not close enough' looks like. mathematicians think everything is an ideal case.