Yes I think we should conserve helium (which is mostly found in natural gas deposits), but not bother quite so much with the natural gas and crude.
My reason: If we run out of helium, we can't make mroe until fusion plants go online, and we can't distribute it until said fusion plants are producing non-radioactive helium. (IANANE-nuclear engineer- so i don't know the reaction that must take place or if the radioactivity of the helium is significant)
Replacements for crude on the other hand are already being produced. (synthetic diesels exist which don't even require engine redesigns) How long will it be before synthetic octane is available? (or we just migrate to already proven diesel engines) It's now a matter of producing those replacements in any mass scale.
Ok so a partial solution would be to populate our own address books with a million fake email addresses. there should be plenty of disk space available for that, (at 20 chars each its only 20 megabytes right?)
Does 2^69 assume working in the dark with only the hash itself? If you have the original file, is it possible to modify it in some way that's "balanced" (produces zero net effect in the hash output) using fewer operations?
what is the source of the spammers lists? I know many people who make up email addresses on the spot, (who is this foo@bar.com that keeps signing up for our lame contest) when confronted with email on forms.
Are you advocating murdering the president by (a) attempting to direct an asteroid into his house (b) shooting at the president's house with tons and tons of rounds (c) lead poisoning, resulting in a new president who will.. also get lead poisoning... or indicating somehow that the president is related to the asteroid?
Orbital mechanics is tricky but it's very well known. In fact, there's only one equation: F=Gm1m2R/r^3 Where R is a vector pointing (from the pov of one mass) towards the other mass. whose magnitude is the distance between the masses, m1 and m2 are the respective masses of the objects in question, G is the gravitational constant, and r is the magnitude of R. (F is a vector also, and in the same direction.)
(ok there are a lot of equations you could use, but all you need is the force equation to numerically calculate any orbit to whatever precision you require - assuming you have good position and velocity data)
Just wash, rinse and repeat for all bodies in the solar system. (or at least all bodies that are close/large enough to have significant interraction)
why so set on Orion? We have already built NERVA engine. The orion concept has only been proved with small conventional explosives afaik.
Looks like the concept is flying 'motorcycle.' the market is probably the same as those who would buy personal watercraft.. except this is not quite up to the level of either. The frame is exposed and not even shiny! This may save weight, but it lacks the aesthetic that sea doo, yamaha and harley davidson have established. Also, the seat: a go-cart seat? It will be ready when it's more like a roller-coaster seat than a homemade dune buggy.
Yes we're really close.. just like they thought before 1989, 1995, 1995-2000. You can't just trot out a list of failures-to-predict as your primary evidence for the the truth of the hypothesis.
Also you have to consider the oil we know is there, but are unwilling to extract... gulf of mexico perhaps...
Not true. the requirements for a roadworthy vehicle are pretty scant (especially for experimental) I think you need a maximum width, turn signals, breaks, and a place to mount the tag.. other than that you could drive around in a hampster powered go-cart.
If things like the moller skycar ever do get produced though, why would we need to drive them any significant distance on roads at all? they can take off vertically from an 8x6 ft square of concrete.
Nuclear will last plenty long. As long as we use thorium breeder reactors. We've got plenty of thorium, but you're right that uranium just won't last much longer than petrol.. (though the reports of the death of either are greatly exaggerated: we should've run out of oil ten years ago according to predictions made in the 70s.)
density helium =.1785 kg/m^3 density air = 1.29 kg/m^3
so the lift of a "pure vacuum" blimp would be about 14% better than that of a helium blimp. So you must make the structural mass of your "vacuum blimp" is smaller than than the extra lift.
Helium should be restricted to uses where there is no practical replacement. Cold temperature research should be the top of the list. Fusion should be next, but this probably won't significantly impact the He market since He-3 is a pretty rare isotope. Gas mixes for deep divers should be somewhere following (commercial before recreational of course). Balloons and Blimps shouldn't even be on the list: Hydrogen is a perfectly accptable replacement, is renewable (can be extracted from water and hydrocarbons) and the danger can be mitigated. hydrogen in childrens balloons would produce a very loud pop if ignited, but you'd have to put a candle to the balloon to do it. Hydrogen in blimps should be safe as long as we don't make the skins out of rocket fuel.
Yes I am aware that divers sometimes replace He with hydrogen, but it has many trade-offs that should not be forced: Under pressure, He/O2 mixes can be explosive, so the mixer must be very careful to limit the partial pressures of each, thermal properties of hydrogen, and the rate of hydrogen take-up in tissues are all factors to consider there.
High volume, low impact uses should at least try to avoid using He, leaving more for people who can get more use out of it.
Darn you hindenburg for creating a huge negative perception of hydrogen. And your crazy announcer too. Think how much cooler our cities would have looked with derigibles floating all over the place.
To be fair, the church got those ideas from previous scientists.. I think i remember reading somewhere that Gallileo or Copernicus got more of a licking from his contemporaries than the church which was funding his research. (but i forget which one and am shaky on the details so ymmv)
OTOH, population density is the enemy of all things wireless: you can only have so much bandwidth per node, so the denser the population, the more nodes (and at lower power so they don't overlap) you must have. So it's probably a wash between dense cities and medium cities since you can space the nodes further apart and up the power in the smaller ones.
No you don't understand. The act of committing the felony is what excludes them from society. We can only elect to bring them back in. We should do so if they really want to come back in.
to the other point: The constitution is designed to guarantee that government will not take away your rights, but it is not the source of those rights. The founders believed that those rights where given to us by our creator. If you don't believe in a creator, you can still believe in inalienable rights. Felony is just the name we put to acts which by defintion deny the existence of such rights. As i said before: Felons do not believe in your rights. You can choose whether to believe in theirs. In fact, as a society, we must choose.
The question as to what should constitute a legal, codified definition of felony will never be resolved and right now includes sale of controlled substances. I will not comment as to whether or not I believe it should include this as i don't believe it relevant to the discussion. (well maybe relevent to this point: If we continue to grant more and more rights to felons, there will be less inhibition to including ever lesser acts in the written definintion o felony.)
No in many states you lose your right to vote forever. In either case, by commiting a felony, you are essencially excluding yourself from the social contract by which you are afforded any rights at all (by ignoring the rights of others). Felons don't believe in your right to property/life/free express, etc. why should you agree to theirs? Certainly there may be some examples of felons who are reformed, but their restoration of rights is and should be at the largess of society at large.
10 or more views?? it's going to look like those lenticular "3D" playing cards.. you know the ones.. where the wrong angle results in you seeing a combo of more than the recommended number of frames.
Err. the single greatest advance cassette recorder technology (apart from its very existance of course) was the complicated gearing systems that enabled the elimination of belts (which are prone to slipping, stretching and breaking).
Re:Why is heat reclamation not worth it?
on
The Not-So-Cool Future
·
· Score: 3, Informative
The maximum amount of useful work you can extract from a heat engine with two temperature pools has been derived and is known as Carnot Efficiency:
eta = (Thot - Tcold)/Thot.
using absolute temperatures (Kelvin or Rankine) So assuming the limit is Thot = 60C = 333 K and Tcold = 25C (average room temp) = 298 K, The maximum efficiency would be 10%. Assuming further that 100W is lost by the chip alone, only 10W would be potentially recoverable. Unfortunately it gets worse: The Carnot cycle is theoretical and no real carnot engine could ever be produced. There are some very efficient cycles available (stirling and rankine come to mind) however none can exceed the carnot efficiency.
It also gets worse as you make the engine smaller. Consider the tolerance of pistons or turbines. Suppose you must leave 1mm of gap between surfaces. For large engines this is no problem, but as the machines become smaller, the minimum gap becomes a greater percentage of the total area.
Machines to extract energy from such a small source at such a low temperature difference have significant theoretical inefficiencies before you even get to the practical ones. This does not mean that you can't recover any of the "wasted heat" but only that you've pretty much gotten all the useful work out of it that you can and recovering the rest would be very impractical.
Have you ever eaten a lobster? did you suck the meat from the legs?
interesting point, Convection is pretty much a fourth-power process (unless you restrict the air from flowing.. then you've just got conduction)
Don't most materials become less conductive as the temperature increases though? thus requireing greater voltage and generating more heat?
Fusion is just as bad as fission regarding wrt radioactive byproducts. Unfortunatly however, the byproducts are gasses - much more complicated to contain than solids. fission breeder reactors are the best option right now, but nothing approaches the energy we could obtain by running heat engines off the core. (even this might not be environmentally acceptible, depending on how big the holes have to be, how much heat must be rejected into the atmosphere, etc.)
Slashdot Mirror
Hey you calling me inconsistent?
Yes I think we should conserve helium (which is mostly found in natural gas deposits), but not bother quite so much with the natural gas and crude.
My reason: If we run out of helium, we can't make mroe until fusion plants go online, and we can't distribute it until said fusion plants are producing non-radioactive helium. (IANANE-nuclear engineer- so i don't know the reaction that must take place or if the radioactivity of the helium is significant)
Replacements for crude on the other hand are already being produced. (synthetic diesels exist which don't even require engine redesigns) How long will it be before synthetic octane is available? (or we just migrate to already proven diesel engines) It's now a matter of producing those replacements in any mass scale.
Ok so a partial solution would be to populate our own address books with a million fake email addresses. there should be plenty of disk space available for that, (at 20 chars each its only 20 megabytes right?)
The US does this sort of thing too. In order to punish one country, we raise prices for goods for our own citizens.
Does 2^69 assume working in the dark with only the hash itself? If you have the original file, is it possible to modify it in some way that's "balanced" (produces zero net effect in the hash output) using fewer operations?
what is the source of the spammers lists? I know many people who make up email addresses on the spot, (who is this foo@bar.com that keeps signing up for our lame contest) when confronted with email on forms.
Are you advocating murdering the president by
(a) attempting to direct an asteroid into his house
(b) shooting at the president's house with tons and tons of rounds
(c) lead poisoning, resulting in a new president who will.. also get lead poisoning...
or indicating somehow that the president is related to the asteroid?
Mr. hun, you have issues.
Orbital mechanics is tricky but it's very well known. In fact, there's only one equation: F=Gm1m2R/r^3
Where R is a vector pointing (from the pov of one mass) towards the other mass. whose magnitude is the distance between the masses, m1 and m2 are the respective masses of the objects in question, G is the gravitational constant, and r is the magnitude of R. (F is a vector also, and in the same direction.)
(ok there are a lot of equations you could use, but all you need is the force equation to numerically calculate any orbit to whatever precision you require - assuming you have good position and velocity data)
Just wash, rinse and repeat for all bodies in the solar system. (or at least all bodies that are close/large enough to have significant interraction)
why so set on Orion? We have already built NERVA engine. The orion concept has only been proved with small conventional explosives afaik.
arg seems i did my math wrong,
1.29/(1.29-.1785) = 1.16
or 16% improvement.
Looks like the concept is flying 'motorcycle.' the market is probably the same as those who would buy personal watercraft.. except this is not quite up to the level of either. The frame is exposed and not even shiny! This may save weight, but it lacks the aesthetic that sea doo, yamaha and harley davidson have established. Also, the seat: a go-cart seat? It will be ready when it's more like a roller-coaster seat than a homemade dune buggy.
Yes we're really close.. just like they thought before 1989, 1995, 1995-2000. You can't just trot out a list of failures-to-predict as your primary evidence for the the truth of the hypothesis.
Also you have to consider the oil we know is there, but are unwilling to extract... gulf of mexico perhaps...
Not true. the requirements for a roadworthy vehicle are pretty scant (especially for experimental) I think you need a maximum width, turn signals, breaks, and a place to mount the tag.. other than that you could drive around in a hampster powered go-cart.
If things like the moller skycar ever do get produced though, why would we need to drive them any significant distance on roads at all? they can take off vertically from an 8x6 ft square of concrete.
Nuclear will last plenty long. As long as we use thorium breeder reactors. We've got plenty of thorium, but you're right that uranium just won't last much longer than petrol.. (though the reports of the death of either are greatly exaggerated: we should've run out of oil ten years ago according to predictions made in the 70s.)
density helium = .1785 kg/m^3
density air = 1.29 kg/m^3
so the lift of a "pure vacuum" blimp would be about 14% better than that of a helium blimp. So you must make the structural mass of your "vacuum blimp" is smaller than than the extra lift.
I really wish they wouldn't fill these things with helium, what with the upcoming helium shortage.i um.html
http://www.energybulletin.net/3135.html and http://wired-vig.wired.com/wired/archive/8.08/hel
detail the problem.
Helium should be restricted to uses where there is no practical replacement. Cold temperature research should be the top of the list. Fusion should be next, but this probably won't significantly impact the He market since He-3 is a pretty rare isotope. Gas mixes for deep divers should be somewhere following (commercial before recreational of course). Balloons and Blimps shouldn't even be on the list: Hydrogen is a perfectly accptable replacement, is renewable (can be extracted from water and hydrocarbons) and the danger can be mitigated. hydrogen in childrens balloons would produce a very loud pop if ignited, but you'd have to put a candle to the balloon to do it. Hydrogen in blimps should be safe as long as we don't make the skins out of rocket fuel.
Yes I am aware that divers sometimes replace He with hydrogen, but it has many trade-offs that should not be forced: Under pressure, He/O2 mixes can be explosive, so the mixer must be very careful to limit the partial pressures of each, thermal properties of hydrogen, and the rate of hydrogen take-up in tissues are all factors to consider there.
High volume, low impact uses should at least try to avoid using He, leaving more for people who can get more use out of it.
Darn you hindenburg for creating a huge negative perception of hydrogen. And your crazy announcer too. Think how much cooler our cities would have looked with derigibles floating all over the place.
To be fair, the church got those ideas from previous scientists.. I think i remember reading somewhere that Gallileo or Copernicus got more of a licking from his contemporaries than the church which was funding his research. (but i forget which one and am shaky on the details so ymmv)
So there's a list of things people never said but got attributed to them anyway..
Re: the goldwyn quote, now that we've heard what actors have to say, it turns out he's right.
OTOH, population density is the enemy of all things wireless: you can only have so much bandwidth per node, so the denser the population, the more nodes (and at lower power so they don't overlap) you must have. So it's probably a wash between dense cities and medium cities since you can space the nodes further apart and up the power in the smaller ones.
No you don't understand. The act of committing the felony is what excludes them from society. We can only elect to bring them back in. We should do so if they really want to come back in.
to the other point: The constitution is designed to guarantee that government will not take away your rights, but it is not the source of those rights. The founders believed that those rights where given to us by our creator. If you don't believe in a creator, you can still believe in inalienable rights. Felony is just the name we put to acts which by defintion deny the existence of such rights. As i said before: Felons do not believe in your rights. You can choose whether to believe in theirs. In fact, as a society, we must choose.
The question as to what should constitute a legal, codified definition of felony will never be resolved and right now includes sale of controlled substances. I will not comment as to whether or not I believe it should include this as i don't believe it relevant to the discussion. (well maybe relevent to this point: If we continue to grant more and more rights to felons, there will be less inhibition to including ever lesser acts in the written definintion o felony.)
No in many states you lose your right to vote forever. In either case, by commiting a felony, you are essencially excluding yourself from the social contract by which you are afforded any rights at all (by ignoring the rights of others). Felons don't believe in your right to property/life/free express, etc. why should you agree to theirs? Certainly there may be some examples of felons who are reformed, but their restoration of rights is and should be at the largess of society at large.
Students are not focused on powerpoint slides. they are sleeping. you just can't tell because the room is dark for the powerpoint.
10 or more views?? it's going to look like those lenticular "3D" playing cards.. you know the ones.. where the wrong angle results in you seeing a combo of more than the recommended number of frames.
Err. the single greatest advance cassette recorder technology (apart from its very existance of course) was the complicated gearing systems that enabled the elimination of belts (which are prone to slipping, stretching and breaking).
The maximum amount of useful work you can extract from a heat engine with two temperature pools has been derived and is known as Carnot Efficiency:
eta = (Thot - Tcold)/Thot.
using absolute temperatures (Kelvin or Rankine)
So assuming the limit is Thot = 60C = 333 K and Tcold = 25C (average room temp) = 298 K, The maximum efficiency would be 10%. Assuming further that 100W is lost by the chip alone, only 10W would be potentially recoverable. Unfortunately it gets worse: The Carnot cycle is theoretical and no real carnot engine could ever be produced. There are some very efficient cycles available (stirling and rankine come to mind) however none can exceed the carnot efficiency.
It also gets worse as you make the engine smaller. Consider the tolerance of pistons or turbines. Suppose you must leave 1mm of gap between surfaces. For large engines this is no problem, but as the machines become smaller, the minimum gap becomes a greater percentage of the total area.
Machines to extract energy from such a small source at such a low temperature difference have significant theoretical inefficiencies before you even get to the practical ones. This does not mean that you can't recover any of the "wasted heat" but only that you've pretty much gotten all the useful work out of it that you can and recovering the rest would be very impractical.
Have you ever eaten a lobster? did you suck the meat from the legs?
interesting point, Convection is pretty much a fourth-power process (unless you restrict the air from flowing.. then you've just got conduction)
Don't most materials become less conductive as the temperature increases though? thus requireing greater voltage and generating more heat?
Fusion is just as bad as fission regarding wrt radioactive byproducts. Unfortunatly however, the byproducts are gasses - much more complicated to contain than solids. fission breeder reactors are the best option right now, but nothing approaches the energy we could obtain by running heat engines off the core. (even this might not be environmentally acceptible, depending on how big the holes have to be, how much heat must be rejected into the atmosphere, etc.)